78 results on '"S. Knollema"'
Search Results
2. 357Cost-effectiveness of sequential SPECT/CT imaging approach for detection of coronary artery disease in comparison to standard care: a multi-center study
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J D Van Dijk, P L Jager, M Mouden, J A Van Dalen, J P Ottervanger, and S Knollema
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Radiology, Nuclear Medicine and imaging ,General Medicine ,Cardiology and Cardiovascular Medicine - Published
- 2019
3. Development and validation of a patient-tailored dose regime in myocardial perfusion imaging using conventional SPECT
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J. D. van Dijk, P. L. Jager, J. P. Ottervanger, J. de Boer, A. H. J. Oostdijk, E. M. Engbers, C. H. Slump, S. Knollema, and J. A. van Dalen
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Male ,Patient-Specific Modeling ,medicine.medical_specialty ,Image quality ,Contrast Media ,Coronary Artery Disease ,Sensitivity and Specificity ,Drug Administration Schedule ,chemistry.chemical_compound ,Myocardial perfusion imaging ,Organophosphorus Compounds ,Patient-Centered Care ,Image Interpretation, Computer-Assisted ,Humans ,Medicine ,Gamma Cameras ,Radiology, Nuclear Medicine and imaging ,Medical physics ,Aged ,Tomography, Emission-Computed, Single-Photon ,medicine.diagnostic_test ,business.industry ,Body Weight ,fungi ,Myocardial Perfusion Imaging ,Reproducibility of Results ,food and beverages ,Equipment Design ,Organotechnetium Compounds ,Image Enhancement ,Cadmium zinc telluride ,Equipment Failure Analysis ,chemistry ,Radiology Nuclear Medicine and imaging ,Female ,Radiopharmaceuticals ,Cardiology and Cardiovascular Medicine ,business ,Nuclear medicine - Abstract
Background: The decreasing image quality in heavier patients can be compensated by administration of a patient-specific dose in myocardial perfusion imaging (MPI) using a cadmium zinc telluride-based SPECT camera. Our aim was to determine if the same can be achieved when using a conventional SPECT camera. Methods: 148 patients underwent SPECT stress MPI using a fixed Tc-99m tetrofosmin tracer dose. Measured photon counts were normalized to administered tracer dose and scan time and were correlated with body weight, body mass index, and mass per length to find the best predicting parameter. From these data, a protocol to provide constant image quality was derived, and subsequently validated in 125 new patients. Results: Body weight was found to be the best predicting parameter for image quality and was used to derive a new dose formula; Aadmin (MBq) = 223·body weight (kg)0.65/Tscan (min). The measured photon counts decreased in heavier patients when using a fixed dose (P < .01) but this was no longer observed after applying a body-weight-dependent protocol (P = .20). Conclusions: Application of a patient-specific protocol resulted in an image quality less depending on patient’s weight. The results are most likely independent of the type of SPECT camera used, and, hence, adoption of patient-specific dose and scan time protocols is recommended.
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- 2015
4. Poster Session 2: Monday 4 May 2015, 08:00-18:00 * Room: Poster Area
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S. E. Bouyoucef, V. Uusitalo, V. Kamperidis, M. De Graaf, T. Maaniitty, I. Stenstrom, A. Broersen, A. Scholte, A. Saraste, J. Bax, J. Knuuti, T. Furuhashi, M. Moroi, T. Awaya, H. Masai, M. Minakawa, T. Kunimasa, H. Fukuda, K. Sugi, A. Berezin, A. Kremzer, O. Clerc, B. Kaufmann, M. Possner, R. Liga, J. Vontobel, F. Mikulicic, C. Graeni, D. Benz, P. Kaufmann, R. Buechel, M. Ferreira, M. Cunha, A. Albuquerque, D. Ramos, G. Costa, J. Lima, M. Pego, A. Peix, L. Cisneros, L. Cabrera, K. Padron, L. Rodriguez, F. Heres, R. Carrillo, E. Mena, Y. Fernandez, E. Huizing, J. Van Dijk, J. Van Dalen, J. Timmer, J. Ottervanger, C. Slump, P. Jager, S. Venuraju, A. Jeevarethinam, A. Yerramasu, S. Atwal, V. Mehta, A. Lahiri, A. Arjonilla Lopez, M. J. Calero Rueda, G. Gallardo, J. Fernandez-Cuadrado, D. Hernandez Aceituno, J. Sanchez Hernandez, H. Yoshida, A. Mizukami, A. Matsumura, O. Smettei, R. Abazid, S. Sayed, A. Mlynarska, R. Mlynarski, K. Golba, M. Sosnowski, S. Winther, M. Svensson, H. Jorgensen, K. Bouchelouche, L. Gormsen, N. Holm, H. Botker, P. Ivarsen, M. Bottcher, C. M. Cortes, E. Aramayo G, M. Daicz, J. Casuscelli, E. Alaguibe, A. Neira Sepulveda, M. Cerda, G. Ganum, M. Embon, J. Vigne, B. Enilorac, A. Lebasnier, L. Valancogne, D. Peyronnet, A. Manrique, D. Agostini, D. Menendez, S. Rajpal, C. Kocherla, M. Acharya, P. Reddy, I. Sazonova, Y. Ilushenkova, R. Batalov, Y. Rogovskaya, Y. Lishmanov, S. Popov, N. Varlamova, S. Prado Diaz, C. Jimenez Rubio, D. Gemma, E. Refoyo Salicio, S. Valbuena Lopez, M. Moreno Yanguela, M. Torres, M. Fernandez-Velilla, J. Lopez-Sendon, G. Guzman Martinez, A. Puente, S. Rosales, C. Martinez, M. Cabada, G. Melendez, R. Ferreira, A. Gonzaga, J. Santos, S. Vijayan, S. Smith, M. Smith, R. Muthusamy, Y. Takeishi, M. Oikawa, J. L. Goral, J. Napoli, O. Montana, A. Damico, M. Quiroz, P. Forcada, J. Schmidberg, N. Zucchiatti, D. Olivieri, A. Dumo, S. Ruano, R. Rakhit, J. Davar, D. Nair, M. Cohen, D. Darko, S. Yokota, A. Maas, M. Mouden, S. Knollema, S. Sanja Mazic, B. Lazovic, M. Marina Djelic, J. Jelena Suzic Lazic, T. Tijana Acimovic, M. Milica Deleva, Z. Vesnina, N. Zafrir, T. Bental, I. Mats, A. Solodky, A. Gutstein, Y. Hasid, D. Belzer, R. Kornowski, R. Ben Said, N. Ben Mansour, H. Ibn Haj Amor, C. Chourabi, A. Hagui, W. Fehri, H. Hawala, Z. Shugushev, A. Patrikeev, D. Maximkin, A. Chepurnoy, V. Kallianpur, A. Mambetov, G. Dokshokov, A. Teresinska, O. Wozniak, A. Maciag, J. Wnuk, A. Dabrowski, A. Czerwiec, J. Jezierski, K. Biernacka, J. Robinson, J. Prosser, G. Cheung, S. Allan, G. Mcmaster, S. Reid, A. Tarbuck, W. Martin, R. Queiroz, A. Falcao, M. Giorgi, R. Imada, S. Nogueira, W. Chalela, R. Kalil Filho, W. Meneghetti, V. Matveev, A. Bubyenov, V. Podzolkov, V. Baranovich, A. Faibushevich, Y. Kolzhecova, O. Volkova, J. Fernandez, G. Lopez, M. Dondi, D. Paez, C. Butcher, E. Reyes, M. Al-Housni, R. Green, H. Santiago, F. Ghiotto, S. Hinton-Taylor, A. Pottle, M. Mason, S. Underwood, I. Casans Tormo, R. Diaz-Exposito, E. Plancha-Burguera, K. Elsaban, H. Alsakhri, K. Yoshinaga, N. Ochi, Y. Tomiyama, C. Katoh, M. Inoue, M. Nishida, E. Suzuki, O. Manabe, Y. Ito, N. Tamaki, A. Tahilyani, F. Jafary, H. Ho Hee Hwa, S. Ozdemir, B. Kirilmaz, A. Barutcu, Y. Tan, F. Celik, S. Sakgoz, M. Cabada Gamboa, A. Puente Barragan, N. Morales Vitorino, M. Medina Servin, C. Hindorf, S. Akil, F. Hedeer, J. Jogi, H. Engblom, V. Martire, E. Pis Diez, M. Martire, D. Portillo, C. Hoff, A. Balche, J. Majgaard, L. Tolbod, H. Harms, J. Soerensen, J. Froekiaer, F. Nudi, G. Neri, E. Procaccini, A. Pinto, M. Vetere, G. Biondi-Zoccai, J. Soares, R. Do Val, M. Oliveira, J. Meneghetti, Y. Tekabe, T. Anthony, Q. Li, A. Schmidt, L. Johnson, M. Groenman, M. Tarkia, M. Kakela, P. Halonen, T. Kiviniemi, M. Pietila, S. Yla-Herttuala, A. Roivainen, S. Nekolla, S. Swirzek, T. Higuchi, S. Reder, S. Schachoff, M. Bschorner, I. Laitinen, S. Robinson, B. Yousefi, M. Schwaiger, T. Kero, L. Lindsjo, G. Antoni, P. Westermark, K. Carlson, G. Wikstrom, J. Sorensen, M. Lubberink, F. Rouzet, T. Cognet, K. Guedj, M. Morvan, F. El Shoukr, L. Louedec, C. Choqueux, A. Nicoletti, D. Le Guludec, A. Jimenez-Heffernan, F. Munoz-Beamud, E. Sanchez De Mora, C. Borrachero, C. Salgado, C. Ramos-Font, J. Lopez-Martin, M. Hidalgo, R. Lopez-Aguilar, E. Soriano, A. Okizaki, M. Nakayama, S. Ishitoya, J. Sato, K. Takahashi, I. Burchert, F. Caobelli, T. Wollenweber, M. Nierada, J. Fulsche, C. Dieckmann, F. Bengel, S. Shuaib, D. Mahlum, S. Port, E. Refoyo, E. Cuesta, G. Guzman, T. Lopez, S. Valbuena, S. Del Prado, M. Moreno, M. Harbinson, L. Donnelly, A. J. Einstein, L. L. Johnson, A. J. Deluca, A. C. Kontak, D. W. Groves, J. Stant, T. Pozniakoff, B. Cheng, L. E. Rabbani, S. Bokhari, C. Schuetze, S. Aguade-Bruix, M. Pizzi, G. Romero-Farina, M. Terricabras, D. Villasboas, J. Castell-Conesa, J. Candell-Riera, S. Brunner, L. Gross, A. Todica, S. Lehner, A. Di Palo, A. Niccoli Asabella, C. Magarelli, A. Notaristefano, C. Ferrari, G. Rubini, A. Sellem, S. Melki, W. Elajmi, H. Hammami, M. Ziadi, J. Montero, J. Ameriso, R. Villavicencio, T. F. Benito Gonzalez, A. Mayorga Bajo, R. Gutierrez Caro, M. Rodriguez Santamarta, L. Alvarez Roy, E. Martinez Paz, C. Barinaga Martin, J. Martin Fernandez, D. Alonso Rodriguez, I. Iglesias Garriz, S. Rosillo, S. Taleb, G. Cherkaoui Salhi, Y. Regbaoui, M. Ait Idir, A. Guensi, C. E. Martin Lopez, and M. Castano Ruiz
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Medical education ,business.industry ,Medicine ,Radiology, Nuclear Medicine and imaging ,General Medicine ,Session (computer science) ,Cardiology and Cardiovascular Medicine ,business - Published
- 2015
5. Poster Session 1: Sunday 3 May 2015, 08:30-18:00 * Room: Poster Area
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Y. Taniguchi, Y. Takahashi, T. Toba, S. Yamada, K. Yokoi, S. Kobayashi, S. Okajima, A. Shimane, H. Kawai, Y. Yasaka, P. Smanio, M. A. Oliveira, L. Machado, P. Cestari, E. Medeiros, S. Fukuzawa, S. Okino, A. Ikeda, J. Maekawa, S. Ichikawa, N. Kuroiwa, K. Yamanaka, A. Igarashi, M. Inagaki, K. Patel, M. Mahan, K. Ananthasubramaniam, M. Mouden, S. Yokota, J. Ottervanger, S. Knollema, J. Timmer, P. Jager, K. Padron, A. Peix, L. Cabrera, V. Pena Bofill, D. Valera, L. Rodriguez Nande, R. Carrillo Hernandez, E. Mena Esnard, Y. Fernandez Columbie, E. Bertella, A. Baggiano, S. Mushtaq, C. Segurini, M. Loguercio, E. Conte, V. Beltrama, M. Petulla', D. Andreini, G. Pontone, B. Guzic Salobir, M. Dolenc Novak, B. Jug, B. Kacjan, Z. Novak, M. Vrtovec, V. Volpato, A. Formenti, M. Pepi, R. Ajanovic, A. Husic-Selimovic, A. Zujovic-Ajanovic, R. Mlynarski, A. Mlynarska, K. Golba, M. Sosnowski, D. Ameta, M. Goyal, D. Kumar, S. Chandra, R. Sethi, A. Puri, S. K. Dwivedi, V. S. Narain, R. K. Saran, S. Nekolla, C. Rischpler, S. Nicolosi, N. Langwieser, R. Dirschinger, K. Laugwitz, M. Schwaiger, J. L. Goral, J. Napoli, P. Forcada, N. Zucchiatti, A. Damico, D. Olivieri, M. Lavorato, E. Dubesarsky, O. Montana, C. Salgado, A. Jimenez-Heffernan, C. Ramos-Font, J. Lopez-Martin, E. Sanchez De Mora, R. Lopez-Aguilar, A. Manovel, A. Martinez, F. Rivera, E. Soriano, N. Maroz-Vadalazhskaya, E. Trisvetova, O. Vrublevskaya, R. Abazid, M. Kattea, H. Saqqah, S. Sayed, O. Smettei, S. Winther, M. Svensson, H. Birn, H. Jorgensen, H. Botker, P. Ivarsen, M. Bottcher, T. Maaniitty, I. Stenstrom, A. Saraste, E. Pikkarainen, V. Uusitalo, H. Ukkonen, S. Kajander, J. Bax, J. Knuuti, T. Choi, H. Park, C. Lee, J. Lee, Y. Seo, Y. Cho, E. Hwang, D. Cho, C. Sanchez Enrique, C. Ferrera, C. Olmos, A. Jimenez - Ballve, M. J. Perez - Castejon, C. Fernandez, D. Vivas, I. Vilacosta, S. Nagamachi, H. Onizuka, R. Nishii, Y. Mizutani, K. Kitamura, M. Lo Presti, V. Polizzi, P. Pino, G. Luzi, D. Bellavia, R. Fiorilli, A. Madeo, J. Malouf, V. Buffa, F. Musumeci, S. Rosales, A. Puente, N. Zafrir, T. Shochat, A. Mats, A. Solodky, R. Kornowski, A. Lorber, A. Boemio, T. Pellegrino, S. Paolillo, V. Piscopo, R. Carotenuto, B. Russo, S. Pellegrino, G. De Matteis, P. Perrone-Filardi, A. Cuocolo, M. Petretta, N. Amirov, M. Ibatullin, A. Sadykov A, G. Saifullina, R. Ruano, M. Diego Dominguez, T. Rodriguez Gabella, A. Diego Nieto, L. Diaz Gonzalez, J. Garcia-Talavera, P. Sanchez Fernandez, A. Leen, I. Al Younis, S. Zandbergen-Harlaar, H. Verberne, A. Gimelli, C. Veltman, R. Wolterbeek, A. Scholte, D. Mooney, J. Rosenblatt, T. Dunn, S. Vasaiwala, K. Okuda, K. Nakajima, K. Nystrom, L. Edenbrandt, S. Matsuo, H. Wakabayashi, M. Hashimoto, S. Kinuya, V. Iric-Cupic, S. Milanov, G. Davidovic, V. Zdravkovic, K. Ashikaga, K. Yoneyama, Y. Akashi, Z. Shugushev, D. Maximkin, A. Chepurnoy, O. Volkova, V. Baranovich, A. Faibushevich, M. El Tahlawi, A. Elmurr, S. Alzubaidi, A. Sakrana, M. Gouda, R. El Tahlawi, A. Sellem, S. Melki, W. Elajmi, H. Hammami, M. Okano, T. Kato, M. Kimura, M. Funasako, E. Nakane, S. Miyamoto, T. Izumi, T. Haruna, M. Inoko, T. Massardo, E. Swett, R. Fernandez, V. Vera, J. Zhindon, R. Alay, S. Ohshima, M. Nishio, A. Kojima, S. Tamai, T. Kobayashi, T. Murohara, S. Burrell, A. Van Rosendael, I. Van Den Hoogen, M. De Graaf, J. Roelofs, L. Kroft, I. Rjabceva, G. Krumina, A. Kalvelis, F. Chanakhchyan, M. Vakhromeeva, E. Kankiya, J. Koppes, R. Knol, M. Wondergem, T. Van Der Ploeg, F. Van Der Zant, S. V. Lazarenko, V. S. Bruin, X. B. Pan, J. M. Declerck, F. M. Van Der Zant, R. J. J. Knol, L. E. Juarez-Orozco, E. Alexanderson, R. Slart, R. Tio, R. Dierckx, C. Zeebregts, H. Boersma, H. Hillege, M. Martinez-Aguilar, A. Jordan-Rios, T. E. Christensen, K. A. Ahtarovski, L. E. Bang, L. Holmvang, H. Soeholm, A. A. Ghotbi, H. Andersson, N. Ihlemann, A. Kjaer, P. Hasbak, M. Gulya, Y. B. Lishmanov, K. Zavadovskii, D. Lebedev, M. Stahle, S. Hellberg, H. Liljenback, J. Virta, O. Metsala, S. Yla-Herttuala, P. Saukko, A. Roivainen, J. Thackeray, Y. Wang, J. Bankstahl, K. Wollert, F. Bengel, Y. Saushkina, V. Evtushenko, S. Minin, I. Efimova, A. Evtushenko, K. Smishlyaev, Y. Lishmanov, L. Maslov, Y. Kirihara, S. Sugino, J. Taki, A. Ahmadian, J. Berman, P. Govender, F. Ruberg, E. Miller, N. Piriou, A. Pallardy, F. Valette, Z. Cahouch, C. Mathieu, K. Warin-Fresse, J. Gueffet, J. Serfaty, J. Trochu, F. Kraeber-Bodere, J. Van Dijk, J. Van Dalen, H. Ofrk, M. Vaturi, Y. Hassid, D. Belzer, A. Sagie, M. Kaminek, I. Metelkova, M. Budikova, P. Koranda, L. Henzlova, E. Sovova, V. Kincl, A. Drozdova, M. Jordan, F. Shahid, Y. Teoh, R. Thamen, N. Hara, M. Onoguchi, O. Hojyo, Y. Kawaguchi, M. Murai, F. Udaka, Y. Matsuzawa, D. S. Bulugahapitiya, M. Avison, J. Martin, Y.-H. Liu, J. Wu, C. Liu, A. Sinusas, D. Daou, R. Sabbah, H. Bouladhour, C. Coaguila, S. Aguade-Bruix, M. Pizzi, G. Romero-Farina, J. Candell-Riera, J. Castell-Conesa, N. Patchett, A. Sverdlov, S. Boulaamayl El Fatemi, L. Sallam, D. Snipelisky, J. Park, J. Ray, B. Shapiro, M. Kostkiewicz, W. Szot, K. Holcman, A. Lesniak-Sobelga, P. Podolec, O. Clerc, M. Possner, R. Liga, J. Vontobel, F. Mikulicic, C. Graeni, D. Benz, B. Herzog, O. Gaemperli, and P. Kaufmann
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Medical education ,business.industry ,Medicine ,Radiology, Nuclear Medicine and imaging ,General Medicine ,Session (computer science) ,Cardiology and Cardiovascular Medicine ,business - Published
- 2015
6. Abstracts
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V. Dunet, A. Dabiri, G. Allenbach, A. Goyeneche Achigar, B. Waeber, F. Feihl, R. Heinzer, J. O. Prior, J. E. Van Velzen, J. D. Schuijf, F. R. De Graaf, M. A. De Graaf, M. J. Schalij, L. J. Kroft, A. De Roos, J. W. Jukema, E. E. Van Der Wall, J. J. Bax, E. Lankinen, A. Saraste, T. Noponen, R. Klen, M. Teras, T. Kokki, S. Kajander, M. Pietila, H. Ukkonen, J. Knuuti, A. P. Pazhenkottil, R. N. Nkoulou, J. R. Ghadri, B. A. Herzog, R. R. Buechel, S. M. Kuest, M. Wolfrum, O. Gaemperli, L. Husmann, P. A. Kaufmann, D. Andreini, G. Pontone, S. Mushtaq, L. Antonioli, E. Bertella, A. Formenti, S. Cortinovis, G. Ballerini, C. Fiorentini, M. Pepi, A. S. Koh, J. S. Flores, F. Y. J. Keng, R. S. Tan, T. S. J. Chua, A. D. Annoni, G. Tamborini, M. Fusari, A. L. Bartorelli, S. H. Ewe, A. C. T. Ng, V. Delgado, J. Schuijf, F. Van Der Kley, A. Colli, A. De Weger, N. A. Marsan, K. H. Yiu, A. C. Ng, S. A. J. Timmer, P. Knaapen, T. Germans, P. A. Dijkmans, M. Lubberink, J. M. Ten Berg, F. J. Ten Cate, I. K. Russel, A. A. Lammertsma, A. C. Van Rossum, Y. Y. Wong, G. Ruiter, P. Raijmakers, W. J. Van Der Laarse, N. Westerhof, A. Vonk-Noordegraaf, G. Youssef, E. Leung, G. Wisenberg, C. Marriot, K. Williams, J. Etele, R. A. Dekemp, J. Dasilva, D. Birnie, R. S. B. Beanlands, R. C. Thompson, A. H. Allam, L. S. Wann, A. H. Nureldin, G. Adelmaksoub, I. Badr, M. L. Sutherland, J. D. Sutherland, M. I. Miyamoto, G. S. Thomas, H. J. Harms, S. De Haan, M. C. Huisman, R. C. Schuit, A. D. Windhorst, C. Allaart, A. J. Einstein, T. Khawaja, C. Greer, A. Chokshi, M. Jones, K. Schaefle, K. Bhatia, D. Shimbo, P. C. Schulze, A. Srivastava, R. Chettiar, J. Moody, C. Weyman, D. Natale, W. Bruni, Y. Liu, E. Ficaro, A. J. Sinusas, A. Peix, E. Batista, L. O. Cabrera, K. Padron, L. Rodriguez, B. Sainz, V. Mendoza, R. Carrillo, Y. Fernandez, E. Mena, A. Naum, T. Bach-Gansmo, N. Kleven-Madsen, M. Biermann, B. Johnsen, J. Aase Husby, S. Rotevatn, J. E. Nordrehaug, J. Schaap, R. M. Kauling, M. C. Post, B. J. W. M. Rensing, J. F. Verzijlbergen, J. Sanchez, G. Giamouzis, N. Tziolas, P. Georgoulias, G. Karayannis, A. Chamaidi, N. Zavos, K. Koutrakis, G. Sitafidis, J. Skoularigis, F. Triposkiadis, S. Radovanovic, A. Djokovic, D. V. Simic, M. Krotin, A. Savic-Radojevic, M. Pljesa-Ercegovac, M. Zdravkovic, J. Saponjski, S. Jelic, T. Simic, R. Eckardt, B. J. Kjeldsen, L. I. Andersen, T. Haghfelt, P. Grupe, A. Johansen, B. Hesse, H. Pena, G. Cantinho, M. Wilk, Y. Srour, F. Godinho, N. Zafrir, A. Gutstein, I. Mats, A. Battler, A. Solodky, E. Sari, N. Singh, A. Vara, A. M. Peters, A. De Belder, S. Nair, N. Ryan, R. James, S. Dizdarevic, G. Depuey, M. Friedman, R. Wray, R. Old, H. Babla, B. Chuanyong, J. Maddahi, E. Tragardh Johansson, K. Sjostrand, L. Edenbrandt, S. Aguade-Bruix, G. Cuberas-Borros, M. N. Pizzi, M. Sabate-Fernandez, G. De Leon, D. Garcia-Dorado, J. Castell-Conesa, J. Candell-Riera, D. Casset-Senon, M. Edjlali-Goujon, D. Alison, A. Delhommais, P. Cosnay, C. S. Low, A. Notghi, J. O'brien, A. C. Tweddel, N. Bingham, P. O Neil, M. Harbinson, O. Lindner, W. Burchert, M. Schaefers, C. Marcassa, R. Campini, P. Calza, O. Zoccarato, A. Kisko, J. Kmec, M. Babcak, M. Vereb, M. Vytykacova, J. Cencarik, P. Gazdic, J. Stasko, A. Abreu, E. Pereira, L. Oliveira, P. Colarinha, V. Veloso, I. Enriksson, G. Proenca, P. Delgado, L. Rosario, J. Sequeira, I. Kosa, I. Vassanyi, C. S. Egyed, G. Y. Kozmann, S. Morita, M. Nanasato, I. Nanbu, Y. Yoshida, H. Hirayama, A. Allam, A. Sharef, I. Shawky, M. Farid, M. Mouden, J. P. Ottervanger, J. R. Timmer, M. J. De Boer, S. Reiffers, P. L. Jager, S. Knollema, G. M. Nasr, M. Mohy Eldin, M. Ragheb, I. Casans-Tormo, R. Diaz-Exposito, F. J. Hurtado-Mauricio, R. Ruano, M. Diego, F. Gomez-Caminero, C. Albarran, A. Martin De Arriba, A. Rosero, R. Lopez, C. Martin Luengo, J. R. Garcia-Talavera, I. E. K. Laitinen, M. Rudelius, E. Weidl, G. Henriksen, H. J. Wester, M. Schwaiger, X. B. Pan, T. Schindler, A. Quercioli, H. Zaidi, O. Ratib, J. M. 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- Subjects
Cardiology and Cardiovascular Medicine - Published
- 2011
7. Death and venous thromboembolism after lower extremity amputation
- Author
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Y. K. Sze, Cees C. P. M. Verheyen, W. M. Fritschy, Harmen B. Ettema, M. C. Struijk-Mulder, W. Van Wijhe, H. R. Büller, S. Knollema, ACS - Amsterdam Cardiovascular Sciences, and Vascular Medicine
- Subjects
Male ,medicine.medical_specialty ,medicine.medical_treatment ,Asymptomatic ,Amputation, Surgical ,Sepsis ,medicine ,Humans ,Prospective cohort study ,Aged ,Aged, 80 and over ,Leg ,business.industry ,Vascular disease ,Incidence ,Incidence (epidemiology) ,Mortality rate ,Venous Thromboembolism ,Hematology ,Middle Aged ,medicine.disease ,Surgery ,Venous thrombosis ,Amputation ,Female ,medicine.symptom ,business - Abstract
Summary. Background: Lower extremity amputation is often performed in patients with end-stage vascular disease and is considered a high-risk procedure. Uncertainty exists about the rate of venous thromboembolism (VTE) in these patients. Objectives: To establish the incidence of death and venous thromboembolism after lower extremity amputation. Methods: A prospective cohort study was performed to establish the incidences of death and VTE after lower extremity amputation, as detected by bilateral complete compression ultrasonography and ventilation-perfusion scintigraphy performed preoperatively and around day 14 postoperatively. Standard low-molecular-weight heparin thromboprophylaxis was given during the study period. A secondary outcome was the incidences of mortality and symptomatic venous thromboembolic complications during 8 weeks of postoperative follow-up. Results: Forty-nine patients (53 amputations) were ultimately included in the intention-to-treat analysis. Five patients died within the 2-week period and an additional seven patients died during the 8 weeks clinical follow-up period. The total mortality rate therefore was 12 of 53 amputations [22.6%; 95% confidence interval (CI), 12.3–36.2%]. Six patients developed pulmonary embolisms (of which two were fatal) and one patient developed an asymptomatic contralateral distal deep venous thrombosis, resulting in a total VTE rate of 7 out of 53 amputations (13.2%; 95% CI, 5.47–25.3%). Conclusion: Lower extremity amputation is accompanied by a high mortality rate from sepsis, and respiratory and vascular causes. This study shows that VTE substantially contributes to the morbidity and mortality after lower extremity amputation despite adequate pharmacological thromboprophylaxis in this vulnerable population of patients.
- Published
- 2010
8. Differential Glutathione Peroxidase mRNA Up-Regulations in Rat Forebrain Areas after Transient Hypoxia-Ischemiaa
- Author
-
Bauke Stuiver, S Knollema, Shinichi Yoshimura, Marcel H. J. Ruiters, Gert J. Ter Horst, J. Korf, and Harold Hom
- Subjects
Male ,GPX3 ,Gene Expression ,Sulfur Radioisotopes ,Hippocampus ,GPX5 ,Gene Expression Regulation, Enzymologic ,General Biochemistry, Genetics and Molecular Biology ,GPX6 ,Prosencephalon ,History and Philosophy of Science ,Animals ,RNA, Messenger ,Rats, Wistar ,Hypoxia, Brain ,In Situ Hybridization ,chemistry.chemical_classification ,Glutathione Peroxidase ,Messenger RNA ,Pyramidal Cells ,General Neuroscience ,Glutathione peroxidase ,Transient hypoxia ,Corpus Striatum ,Rats ,Cell biology ,chemistry ,Ischemic Attack, Transient ,Organ Specificity ,Forebrain ,Autoradiography - Published
- 2006
9. [Regadenoson as a new stress agent in myocardial perfusion imaging. Initial experience in The Netherlands]
- Author
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P L, Jager, M, Buiting, M, Mouden, A H J, Oostdijk, J, Timmer, and S, Knollema
- Subjects
Adult ,Aged, 80 and over ,Male ,Tomography, Emission-Computed, Single-Photon ,Adenosine ,Adenosine A2 Receptor Agonists ,Myocardial Perfusion Imaging ,Coronary Disease ,Heart ,Middle Aged ,Dyspnea ,Purines ,Surveys and Questionnaires ,Tachycardia ,Injections, Intravenous ,Exercise Test ,Flushing ,Humans ,Pyrazoles ,Female ,Atrioventricular Block ,Aged ,Netherlands - Abstract
Regadenoson is a recently approved selective adenosine-2A receptor agonist to induce pharmacological stress in myocardial perfusion imaging (MPI) procedures using a single bolus injection.We included 123 patients referred for MPI because of suspected coronary arterial disease (CAD). Of these, 66 patients underwent a regadenoson stress test and 57 patients underwent an adenosine stress test preceding standard myocardial SPECT imaging. Technicians, physicians and patients were asked to report their experience using questionnaires.As compared to adenosine, regadenoson did not produce any atrio-ventricular block (0 vs. 10% with adenosine), but did produce minor tachycardia and minimal blood pressure changes while all other side effects were milder and shorter. There were fewer patients with severe complaints after taking regadenoson than adenosine (17% vs. 32%, respectively, p0.01). The most frequent complaint reported was dyspnea, followed by flushing and chest pain. However, when they did occur, they usually disappeared rapidly. The overall symptom score, including severity and duration of side effects, was significantly lower after regadenoson than after adenosine (6.7±6.3 vs. 10.0±7.9, respectively; p0.01.) SPECT imaging results were similar. The regadenoson procedure was faster and more practical.Regadenoson, the new selective adenosine-2A receptor agonist, is a stress agent for MPI with a patient- and department friendly profile.
- Published
- 2014
10. Differential effects of CRH infusion into the central nucleus of the amygdala in the Roman high-avoidance and low-avoidance rats
- Author
-
A. Wiersma, S. Knollema, Béla Bohus, Jaap M. Koolhaas, and Jan Pieter Konsman
- Subjects
Nervous system ,Male ,Endocrinology, Diabetes and Metabolism ,LINES ,Corticotropin-releasing hormone ,Endocrinology ,Heart Rate ,Basal ganglia ,Adaptation, Psychological ,Neural Pathways ,Brain Mapping ,Central nucleus of the amygdala ,FOS ,Fear ,Amygdala ,Psychiatry and Mental health ,medicine.anatomical_structure ,STRESS-FREE CONDITIONS ,EXPLORATORY-BEHAVIOR ,CRH mRNA ,Brainstem ,Psychology ,Arousal ,hormones, hormone substitutes, and hormone antagonists ,medicine.medical_specialty ,endocrine system ,Genotype ,Central nervous system ,HEART-RATE ,corticotropin-releasing hormone ,Autonomic Nervous System ,CORTICOTROPIN-RELEASING FACTOR ,central amygdaloid nucleus ,Internal medicine ,medicine ,Avoidance Learning ,Animals ,Lateral parabrachial nucleus ,EXPOSURE ,Biological Psychiatry ,FACTOR ANTAGONIST ,Endocrine and Autonomic Systems ,Rats, Inbred Strains ,RHA/RLA rats ,NEUROENDOCRINE TRAITS ,NERVOUS-SYSTEM ,Rats ,behaviour ,Hormone ,Brain Stem ,RESPONSES - Abstract
Roman-high (RHA/Verh) and low (RLA/Verh) avoidance rats are selected and bred for rapid learning versus non-acquisition of two-way, active avoidance behaviour in a shuttle box. RHA/Verh rats generally show a more active coping style than do their RLA/Verh counterparts when exposed to various environmental challenges. The central nucleus of the amygdala (CeA) is known to be involved in the regulation of autonomic, neuroendocrine and behavioural responses to stress and stress-free conditions, and it is considered in relation to coping strategies. Corticotropin-releasing hormone (CRH) seems to be a key factor in the control of the CeA output. Neuroanatomical studies have revealed that the majority of CRH fibers from the CeA have direct connections with autonomic regulatory nuclei in the brainstem, e.g. lateral parabrachial nucleus (lPB), ventrolateral periaquaductal gray (vlPAG). The modulating effects of CRH (30 ng) on CeA activity were studied by infusion of CRH into the CeA in freely moving male RHA/Verh and RLA/Verh rats under stress-free conditions. Heart-rate and behavioural activities were repeatedly measured before, during and after local administration of CRH or vehicle, after which early gene product FOS immunocytochemistry and CRH-mRNA in situ hybridisation were carried out in selected brain areas. CRH infusion into the CeA caused a long lasting increase in heart-rate and behavioural activation in the RHA/Verh rats, leaving the RLA/Verh rats unaffected. As a result of CRH infusion, the number of FOS positive cells in the CeA and lPB of RLA/Verh rats was increased whereas an opposite response was found in the RHA/Verh rats. However, CRH into the CeA of the Roman rat lines induced no pronounced effects on FOS staining in the vlPAG and CRH mRNA levels in the CeA. These results indicate that the CRH system of the CeA, connected with the output brainstem areas, is differentially involved in cardiovascular and behavioural responses. © 1998 Elsevier Science Ltd. All rights reserved.
- Published
- 1998
11. Metyrapone Reduces Rat Brain Damage and Seizures after Hypoxia—Ischemia: An Effect Independent of Modulation of Plasma Corticosterone Levels?
- Author
-
ter Gert Horst, S Knollema, Jakob Korf, Rha Kemper, and HJ Krugers
- Subjects
Blood Glucose ,Male ,hippocampus ,medicine.medical_treatment ,Body Temperature ,Brain Ischemia ,030218 nuclear medicine & medical imaging ,Brain ischemia ,NUMBER ,chemistry.chemical_compound ,Epilepsy ,0302 clinical medicine ,Corticosterone ,Hypoxia, Brain ,NEURONS ,Chemistry ,brain damage ,EXCITATORY AMINO-ACIDS ,Neuroprotective Agents ,Neurology ,HIPPOCAMPAL ASTROCYTES ,Brain Damage, Chronic ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,Locomotion ,medicine.drug ,medicine.medical_specialty ,medicine.drug_class ,ischemia ,ADRENALECTOMY ,Brain damage ,03 medical and health sciences ,Internal medicine ,INJURY ,medicine ,Animals ,EXPOSURE ,Rats, Wistar ,ACCUMULATION ,Metyrapone ,corticosterone ,Adrenalectomy ,KAINIC ACID ,medicine.disease ,Rats ,Anticonvulsant ,Endocrinology ,Mineralocorticoid ,epilepsy ,Neurology (clinical) ,030217 neurology & neurosurgery - Abstract
Hypoxia-ischemia is accompanied by abundant corticosterone secretion that could exacerbate brain damage after the insult. The authors demonstrate that the steroid synthesis inhibitor metyrapone (150 mg/kg subcutaneously) suppresses the hypoxia-ischemia-induced rise of plasma corticosterone levels (17.3 +/- 3.6 micrograms/dL) when compared with corticosterone-treated animals (72.2 +/- 4.8 micrograms/dL) immediately after hypoxia-ischemia. In parallel, metyrapone reduced brain damage (P < 0.05). Moreover, none of the metyrapone-treated animals displayed seizures, whereas seven of eight corticosterone-treated animals had seizures after hypoxia-ischemia. Although corticosterone administration in metyrapone-treated animals elevated plasma corticosterone levels (39.0 +/- 5.3 micrograms/dL), this did not result in a subsequent increase in brain damage and seizures when compared with metyrapone-treated animals. The authors conclude that metyrapone reduces brain damage and the incidence of seizures after hypoxia-ischemia but that this effect might partially be independent from its effect on modulating plasma corticosterone levels.
- Published
- 1998
12. Long-term food restriction, deprenyl, and nimodipine treatment on life expectancy and blood pressure of stroke-prone rats
- Author
-
G De Jong, Jakob Korf, H. Stevens, Pgm Luiten, and S Knollema
- Subjects
Male ,Aging ,Monoamine Oxidase Inhibitors ,hypertension ,PATHOPHYSIOLOGY ,Hemodynamics ,Brain damage ,food restriction ,DISEASE ,BRAIN-DAMAGE ,Life Expectancy ,Rats, Inbred SHR ,Selegiline ,medicine ,Animals ,deprenyl ,cardiovascular diseases ,LONGEVITY ,Nimodipine ,Stroke ,SPONTANEOUSLY HYPERTENSIVE RATS ,business.industry ,General Neuroscience ,Body Weight ,Antagonist ,blood pressure ,nimodipine ,SPAN ,medicine.disease ,Calcium Channel Blockers ,Survival Analysis ,Pathophysiology ,Rats ,Cerebrovascular Disorders ,Blood pressure ,FOCAL CEREBRAL-ISCHEMIA ,Anesthesia ,stroke-prone rats ,Neurology (clinical) ,stroke prevention ,Geriatrics and Gerontology ,medicine.symptom ,HYPOXIA-ISCHEMIA ,business ,Food Deprivation ,Developmental Biology ,medicine.drug - Abstract
We determined whether food restriction or the drugs nimodipine (Ca2+ antagonist) and deprenyl (a MAO-B inhibitor) prevent the development of stroke in the spontaneously hypertensive stroke-prone rat (SHR-SP). Forty male SHR-SP rats, in the age of 34 weeks, were exposed to various treatments. During a period of 27 weeks, survival and blood pressure were followed. In the control and deprenyl group, the blood pressure Values remained unchanged; 50% had died after 27 weeks. All rats that were treated with nimodipine survived. After food restriction, 7/8 rats survived and showed a lower blood pressure. This study in SHR-PR rats shows the superiority of nimodipine on survival, and the potential of food restriction as a stroke-preventing measure. (C) 1998 Elsevier Science Inc.
- Published
- 1998
13. The number of insults and the cerebral damage after hypoxia/ischemia are altered after acute pretreatment with corticosterone and metyrapone
- Author
-
Harm J. Krugers, Jakob Korf, A. Wiersma, G.J. Ter Horst, S Knollema, and Richard H.A. Kemper
- Subjects
medicine.medical_specialty ,medicine.medical_treatment ,Ischemia ,ASTROCYTES ,Hypoxia ischemia ,REDUCES BRAIN-DAMAGE ,RATS ,HIPPOCAMPAL DAMAGE ,chemistry.chemical_compound ,Corticosterone ,Neuronal damage ,PITUITARY ,Internal medicine ,INJURY ,medicine ,neuronal damage ,Stroke ,silver staining ,seizures ,Metyrapone ,business.industry ,CORTISOL ,General Neuroscience ,Adrenalectomy ,EARLY SEIZURES ,medicine.disease ,stroke ,Endocrinology ,chemistry ,GLUCOCORTICOID ENDANGERMENT ,Cerebral damage ,business ,ACUTE STROKE ,medicine.drug - Abstract
The role of glucocorticoids in neuronal viability is controversial. Most studies which describe the effects of glucocorticoids on ischemic brain damage use surgical adrenalectomy to induce a reduction in plasma corticosterone levels. In the present study we used metyrapone, a corticosterone synthesis inhibitor, to examine the effects of acute manipulation of corticosterone levels on neuronal damage and seizures. Shortly before transient hypoxia/ischemia, animals were subcutaneously injected with sesame oil, metyrapone, corticosterone or corticosterone + metyrapone. Both the neuronal damage and the percentage animals with seizures were found to correlate well with plasma corticosterone levels. This relation between affected area, seizures and corticosterone levels was confirmed when the rats were re-arranged into animals with and without seizures. However, Corticosterone administration in metyrapone treated rats did not result (compared to MET treatment) in an increased neuronal damage. This suggests that the beneficial effects of metyrapone may be regulated by a corticosterone independent mechanism.
- Published
- 1997
14. [Untitled]
- Author
-
Béla Bohus, S. Knollema, A. Wiersma, Jan Pieter Konsman, and Jaap M. Koolhaas
- Subjects
Nervous system ,Vasopressin ,medicine.medical_specialty ,Central nucleus of the amygdala ,Antagonist ,Amygdala ,Corticotropin-releasing hormone ,Endocrinology ,medicine.anatomical_structure ,Internal medicine ,Genetics ,medicine ,Lateral parabrachial nucleus ,Psychology ,Genetics (clinical) ,Ecology, Evolution, Behavior and Systematics ,Hormone - Abstract
Roman high (RHA/Verh)- and low (RLA/Verh)-avoidance rats are selected and bred for rapid versus nonacquisition of two-way, active avoidance behavior in the shuttle box. RHA/Verh rats generally show a more active coping style than do their RLA/Verh counterparts when exposed to various environmental challenges. The central nucleus of the amygdala (CeA) is known to be involved in the regulation of autonomic, neuroendocrine, and behavioral responses to stress. Its involvement in the selection of coping strategies has also been suggested. Corticotropin-releasing hormone (CRH) seems to be one of the key neurohormones in the control of CeA output. Neuroanatomical studies have revealed that the majority of CRH fibers from the CeA have direct connections with autonomic regulatory nuclei in the brain-stem, e.g. lateral parabrachial nucleus (lPB). The effects of CRH (30 ng) on modulating CeA activity were studied by infusion of CRH into the CeA during conditioned stress (inescapable foot-shocks) in RHA/Verh and RLA/Verh male rats. Heart-rate responses after CRH treatment were not changed in either line. However, distinctly different behavioral responses were seen after CRH infusion into the CeA of both rat lines. A decrease in immobility responses was seen in both RHA/Verh and RLA/Verh rats, while an increase in exploration was observed in RHA/Verh rats only in the conditioned stress situation. Rearing levels were increased in the RHA/Verh rats, whereas they were decreased in the RLA/Verh animals. As a result of CRH infusion, the number of FOS immunoreactive cells in the lPB of RLA/Verh rats was decreased, whereas an opposite response was found in RHA/Verh rats. These results indicate that the CRH system of the CeA connected with output brain-stem areas is differentially involved in the cardiovascular and behavioral responses of these rats having different coping styles.
- Published
- 1997
15. Immunolocalization of glutathione reductase in the murine brain
- Author
-
S Knollema, Jakob Korf, Harold Hom, ter Gert Horst, and H Schirmer
- Subjects
Glutathione reductase ,Substantia nigra ,PREFRONTAL CORTEX ,Biology ,IMMUNOHISTOCHEMICAL LOCALIZATION ,chemistry.chemical_compound ,PARKINSONS-DISEASE ,CYTOCHROME-OXIDASE ,distribution ,SUPEROXIDE-DISMUTASE ,rat ,TISSUE ANTIOXIDANT STATUS ,OXIDATIVE STRESS ,mouse ,chemistry.chemical_classification ,reactive oxygen species ,TRANSGENIC MICE ,Reactive oxygen species ,Pars compacta ,General Neuroscience ,Glutathione peroxidase ,Dentate gyrus ,Glutathione ,SPECIES-RELATED VARIATIONS ,Molecular biology ,scavenger enzymes ,chemistry ,nervous system ,Forebrain ,MESSENGER-RNA - Abstract
Free radical species arise from the univalent reduction of oxygen. The cytosolic agent H2O2, produced during enzymatic scavenging of the superoxide radical (. O-2-) is in turn removed predominantly via the oxidation of reduced glutathione (GSH) to the oxidized form (GSSG) by glutathione peroxidase. Subsequently GSSG is recycled back to GSH by glutathione reductase (GSH-red). Little is known about the distribution of this enzyme in the brain. The aim of this study was to determine the distribution of this enzyme in the brain of different murine species by means of immunocytochemical techniques, although most attention was given to the distribution of GSH-red in the forebrain. In most brain areas GSH-red positive neurons were detected, but the regional intracellular staining intensity differed markedly. The pre-piriform and piriform cortices, the pyramidal cell layers of the hippocampus, and the dentate gyrus were heavily stained. The caudate nucleus displayed a progressive increase in the intracellular staining intensity from the rostral to the caudolateral parts. Furthermore, in the thalamus, there was a gradual decrease in GSH-red staining from the medial to-the lateral parts. The mesencephalon was poor in immunopositive cells, and in the substantia nigra pars reticulata, almost no labeling was detected. However, the substantia nigra pars compacta showed an intense GSH-red immunoreactivity. The results show a specific localization of glutathione reductase in distinct brain regions, suggesting a variable potency of different brain areas in dealing with the damaging oxidative actions of free radicals. Also, differential GSH-red expression patterns were found in the various murine species. Some species showed a pronounced GSH-red immunoreactivity in glial cells, specifically in regions that lacked neuronal GSH-red immunoreactivity. (C) 1996 Wiley-Liss, Inc.
- Published
- 1996
16. Ebselen (PZ-51) protects the Caudate putamen against hypoxia/ischemia induced neuronal damage
- Author
-
K Nicolay, JW Elting, Jakob Korf, ter Gert Horst, Rick M. Dijkhuizen, S Knollema, and Mechanical Engineering
- Subjects
CUZN-SUPEROXIDE-DISMUTASE ,striatum ,Ischemia ,hydrogen peroxide ,Brain damage ,Striatum ,Pharmacology ,Lipid peroxidation ,chemistry.chemical_compound ,medicine ,ACTIVE ORGANOSELENIUM COMPOUND ,BRAIN ,glutathione peroxidase ,chemistry.chemical_classification ,DiMethylSulfOxide ,Ebselen ,General Neuroscience ,Glutathione peroxidase ,DIMETHYL-SULFOXIDE ,MONOAMINE-OXIDASE ,Glutathione ,Hypoxia (medical) ,medicine.disease ,radicals ,LIPID-PEROXIDATION ,LYMPHOCYTE MIGRATION ,GLUTATHIONE-PEROXIDASE ,chemistry ,Biochemistry ,FOCAL CEREBRAL-ISCHEMIA ,INFLAMMATORY REACTIONS ,medicine.symptom - Abstract
Ebselen, a synthetic selenium-containing compound which exhibits glutathione peroxidase-like activity in vivo, is known for its beneficial effects on inflammation and tissue injury. Experiments were conducted to test whether ebselen dissolved in DiMethylSulfOxide (DMSO) could prevent damage in a rat model for transient unilateral hypoxia/ischemia.Results indicate that ebselen dissolved in DMSO reduced damage in the caudate putamen, the thalamus and the cortex compared to the saline controls. The average damage in the Caudate putamen was also significantly lower in the ebselen group when compared to the DMSO treated rats. Total brain damage in the ebselen group was decreased by 76%. DMSO alone did not reduce damage significantly in any of the analyzed areas. Some protective effects of ebselen, however, may be due to the solvent DMSO. In the caudate putamen ebselen alone was responsible for the observed protection. This protective effect of ebselen might be explained by its actions as a glutathione peroxidase mimic.
- Published
- 1996
17. Novel Hypothalamic and Preoptic Sites of Prepro-Melanin-Concentrating Hormone Messenger Ribonucleic Acid and Peptide Expression in Lactating Rats
- Author
-
Wylie Vale, E. R. Brown, S. Knollema, and P. E. Sawchenko
- Subjects
endocrine system ,medicine.medical_specialty ,Melanin-concentrating hormone ,Endocrine and Autonomic Systems ,Endocrinology, Diabetes and Metabolism ,Neuropeptide ,Biology ,Preoptic area ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Endocrinology ,medicine.anatomical_structure ,chemistry ,Hypothalamus ,Posterior pituitary ,Internal medicine ,Median eminence ,medicine ,Zona incerta ,hormones, hormone substitutes, and hormone antagonists ,Cellular localization - Abstract
The deduced structure of the rat melanin-concentrating hormone (MCH) precursor predicted the existence of at least two peptides that may be processed from it, one similar to teleost MCH and a second novel neuropeptide, NEI. Cellular localization studies confirmed that prepro-MCH (ppMCH) mRNA and the MCH and NEI peptides are expressed predominantly in cells in the zona incerta and caudal lateral hypothalamic area with minor contingents seen in the olfactory tubercle and pons. A moderate MCH-and NEI-immunoreactive axonal projection to the median eminence and, particularly, to oxytocin-rich regions of the posterior pituitary suggested some anatomical heterogeneity of ppMCH-expressing neurons in the hypothalamus, and an involvement in neuroendocrine function. In the present study, immunohistochemical and hybridization histochemical methods were used to follow MCH gene and peptide expression as a function of reproductive status in female rats. Nursing dams sacrificed after 8 to 21 days of lactation consistently displayed ppMCH mRNA and MCH and NEI immunoreactivity in a discrete and contiguous band, encompassing the ventral aspect of the medial part of the medial preoptic nucleus, the periventricular preoptic nucleus, and the most rostral aspects of the paraventricular nucleus of the hypothalamus (PVH). Combined immunohistochemical (for oxytocin) and hybridization histochemical (for ppMCH mRNA) staining failed to reveal a significant degree of congruence in the two chemically-specified cell populations in the PVH of lactating dams. The apparent induction of ppMCH-derived peptides and mRNA in the preoptic area and PVH was not apparent in animals sacrificed 4 to 8 days after weaning, during late pregnancy, or at any point in the estrous cycle. Moreover, no frank alterations in ppMCH mRNA were evident in the principal sites at which ppMCH is expressed at constitutively high levels, i.e. in the lateral hypothalamic area and zona incerta, as a function of reproductive status. The loci and apparent state-dependency of the induction of ppMCH mRNA and peptide expression suggests a role for these gene products in the control of lactation.
- Published
- 1992
18. Cobalt-57 as a SPET tracer in the visualization of ischaemic brain damage in patients with middle cerebral artery stroke
- Author
-
D. A. Piers, J. De Reuck, Jakob Korf, Rudi Dierckx, H. Jansen, S Knollema, A. E.J. De Jager, H. Stevens, and C. Van de Wiele
- Subjects
Adult ,Male ,medicine.medical_specialty ,INFLUX ,CALCIUM ACCUMULATION ,POSITRON EMISSION TOMOGRAPHY ,Cerebral arteries ,PATHOPHYSIOLOGY ,Ischemia ,chemistry.chemical_element ,Brain damage ,DELAYED NEURONAL DEATH ,Central nervous system disease ,T-LYMPHOCYTES ,Internal medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Tissue Distribution ,PROGRESSIVE MULTIPLE-SCLEROSIS ,Cobalt Radioisotopes ,Stroke ,Aged ,Tomography, Emission-Computed, Single-Photon ,medicine.diagnostic_test ,Vascular disease ,business.industry ,Brain ,General Medicine ,IN-VITRO ,Cerebral Arteries ,Middle Aged ,medicine.disease ,Surgery ,Cerebrovascular Disorders ,chemistry ,Positron emission tomography ,TISSUE ,ISCHEMIC STROKE ,Cardiology ,Brain Damage, Chronic ,Female ,medicine.symptom ,Radiopharmaceuticals ,business ,Cobalt - Abstract
In PET studies we have shown the usefulness of cobalt radionuclides for the visualization and quantification of ischaemic damage in stroke. In the present study, we explored Co-57(2+) as a SPET tracer. Uptake of radioactivity was estimated by using a cobalt enhancement ratio defined as the ratio of cobalt uptake in the affected region versus a similar volume in the non-affected contralateral side. Clinical status was assessed with the Orgogozo stroke score at the time of scanning and at least 60 days after admission. Nineteen patients (11 men, 8 women) with a middle cerebral artery stroke were examined with Co-57(2+) SPET 0-30 days after stroke onset. Our investigations show enhanced cobalt uptake in the infarcted brain tissue in patients with a major stroke and little clinical improvement. There was a significant correlation between the cobalt enhancement ratio and the Orgogozo score at the time of scanning and discharge. Our results suggest that Co-57(2+) SPET is suitable for determining the extent of (possibly calcium-mediated) damage in stroke and in the assessment of potential therapeutic interventions. ((C) 1998 Lippincoft-Raven Publishers).
- Published
- 1998
19. Corticotropin-releasing hormone modulation of a conditioned stress response in the central amygdala of Roman high (RHA/Verh)-avoidance and low (RLA/Verh)-avoidance rats
- Author
-
A, Wiersma, S, Knollema, J P, Konsman, B, Bohus, and J M, Koolhaas
- Subjects
Cardiovascular Physiological Phenomena ,Male ,Analysis of Variance ,Behavior, Animal ,Corticotropin-Releasing Hormone ,Conditioning, Psychological ,Avoidance Learning ,Animals ,Rats, Inbred Strains ,Amygdala ,Stress, Psychological ,Rats - Abstract
Roman high (RHA/Verh)- and low (RLA/Verh)-avoidance rats are selected and bred for rapid versus nonacquisition of two-way, active avoidance behavior in the shuttle box. RHA/Verh rats generally show a more active coping style than do their RLA/Verh counterparts when exposed to various environmental challenges. The central nucleus of the amygdala (CeA) is known to be involved in the regulation of autonomic, neuroendocrine, and behavioral responses to stress. Its involvement in the selection of coping strategies has also been suggested. Corticotropin-releasing hormone (CRH) seems to be one of the key neurohormones in the control of CeA output. Neuroanatomical studies have revealed that the majority of CRH fibers from the CeA have direct connections with autonomic regulatory nuclei in the brain-stem, e.g. lateral parabrachial nucleus (lPB). The effects of CRH (30 ng) on modulating CeA activity were studied by infusion of CRH into the CeA during conditioned stress (inescapable foot-shocks) in RHA/Verh and RLA/Verh male rats. Heart-rate responses after CRH treatment were not changed in either line. However, distinctly different behavioral responses were seen after CRH infusion into the CeA of both rat lines. A decrease in immobility responses was seen in both RHA/Verh and RLA/Verh rats, while an increase in exploration was observed in RHA/Verh rats only in the conditioned stress situation. Rearing levels were increased in the RHA/Verh rats, whereas they were decreased in the RLA/Verh animals. As a result of CRH infusion, the number of FOS immunoreactive cells in the lPB of RLA/Verh rats was decreased, whereas an opposite response was found in RHA/Verh rats. These results indicate that the CRH system of the CeA connected with output brain-stem areas is differentially involved in the cardiovascular and behavioral responses of these rats having different coping styles.
- Published
- 1998
20. Dynamics of cerebral tissue injury and perfusion after temporary hypoxia-ischemia in the rat : evidence for region-specific sensitivity and delayed damage
- Author
-
Dick J. De Wildt, S Knollema, H. Bart van der Worp, Jan Willem Berkelbach van der Sprenkel, Klaas Nicolay, Rick M. Dijkhuizen, Kees A. F. Tulleken, Gert J. Ter Horst, and Mechanical Engineering
- Subjects
APPARENT DIFFUSION-COEFFICIENT ,Male ,medicine.medical_specialty ,Pathology ,Time Factors ,ENERGY-METABOLISM ,Ischemia ,Hemodynamics ,Brain damage ,GERBIL ,BRAIN-DAMAGE ,Body Water ,SELECTIVE NEURONAL VULNERABILITY ,Internal medicine ,selective vulnerability ,medicine ,Laser-Doppler Flowmetry ,Animals ,GLOBAL-ISCHEMIA ,Cerebral perfusion pressure ,Rats, Wistar ,Hypoxia ,Stroke ,Advanced and Specialized Nursing ,Brain Mapping ,BLOOD-FLOW ,medicine.diagnostic_test ,business.industry ,Magnetic resonance imaging ,Blood flow ,medicine.disease ,Magnetic Resonance Imaging ,Rats ,TIME COURSE ,Oxygen ,Carotid Arteries ,Ischemic Attack, Transient ,Reperfusion Injury ,Cardiology ,cerebral ischemia, transient ,TRANSIENT FOREBRAIN ISCHEMIA ,Neurology (clinical) ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,STROKE - Abstract
Background and Purpose —Selective regional sensitivity and delayed damage in cerebral ischemia provide opportunities for directed and late therapy for stroke. Our aim was to characterize the spatial and temporal profile of ischemia-induced changes in cerebral perfusion and tissue status, with the use of noninvasive MRI techniques, to gain more insight in region-specific vulnerability and delayed damage. Methods —Rats underwent 20 minutes of unilateral cerebral hypoxia-ischemia (HI). We performed combined repetitive quantitative diffusion-weighted, T2-weighted, and dynamic susceptibility contrast-enhanced MRI from before HI to 5 hours after HI. Data were correlated with parallel blood oxygenation level–dependent MRI and laser-Doppler flowmetry. Finally, MRI and histology were done 24 and 72 hours after HI. Results —Severe hypoperfusion during HI caused acute reductions of the apparent diffusion coefficient (ADC) of tissue water in the ipsilateral hemisphere. Reperfusion resulted in dynamic perfusion alterations that varied spatially. The ADC recovered completely within 1 hour in the hippocampus (from 0.68±0.07 to 0.83±0.09×10 −3 mm 2 /s), cortex (from 0.56±0.06 to 0.77±0.07×10 −3 mm 2 /s), and caudate putamen (from 0.58±0.06 to 0.75±0.06×10 −3 mm 2 /s) but only partially or not at all in the thalamus (from 0.65±0.07 to 0.68±0.12×10 −3 mm 2 /s) and substantia nigra (from 0.80±0.08 to 0.76±0.10×10 −3 mm 2 /s). Secondary ADC reductions, accompanied by significant T2 elevations and histological damage, were observed after 24 hours. Initial and secondary ADC decreases were observed invariably in the hippocampus, cortex, and caudate putamen and in approximately 70% of the animals in the thalamus and substantia nigra. Conclusions —Region-specific responses and delayed ischemic damage after transient HI were demonstrated by MRI. Acute reperfusion-induced normalization of ADCs appeared to poorly predict ultimate tissue recovery since secondary, irreversible damage developed eventually.
- Published
- 1998
21. Glia and the Development of Brain Damage
- Author
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S Knollema, G.J. Ter Horst, and S. V. van de Witte
- Subjects
medicine.medical_specialty ,Glial fibrillary acidic protein ,biology ,Chemistry ,Period (gene) ,Ischemia ,Cerebral hypoxia ,Infarction ,Depolarization ,Substantia nigra ,Brain damage ,medicine.disease ,Endocrinology ,Internal medicine ,medicine ,biology.protein ,medicine.symptom - Abstract
Transient cerebral hypoxia/ischemia triggers a differential sequence of damage development, which can be distinguished on the basis of the duration of both the period of oxygen shortage and the post-ischemic reperfusion period (figure 1). Development of neuronal damage can be divided into three main patterns; Acute(infarction), early and delayed neuronal damage. Long ischemic periods cause acute (after 3 hours) neuronal and astroglial cell death (1,2), possibly as a consequence of high intracellular acidosis by ionic pump failure. Early damage occurs after 3 hours and is characterized by selective neuronal degeneration most likely a consequence of progressing depolarization events due to a decreased activity of the enzyme Na+/K+ ATP-ase (3,4). Delayed damage becomes apparent between 24 and 72 hours and is also selective neuronal (5,6).
- Published
- 1997
22. L-Deprenyl Reduces Brain Damage in the Caudate Putamen by a Mao-Dependent Effect
- Author
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A. Wiersma, S Knollema, and G. J. Ter Horst
- Subjects
biology ,MPTP ,Selegiline ,Ischemia ,Brain damage ,Hypoxia (medical) ,Pharmacology ,Free radical scavenger ,medicine.disease ,Neuroprotection ,chemistry.chemical_compound ,chemistry ,Catalase ,medicine ,biology.protein ,medicine.symptom ,medicine.drug - Abstract
In our experimental hypoxia/ischemia (Levine) model several potential protective pretreatments (1—3) were tested on their ability to reduce damage and L-deprenyl (selegiline) proved to be a very effective neuroprotective agent as it is in reducing brain damage when it is applied for 14 days prior to hypoxia/ischemia (4,5). The mechanism through which L-deprenyl diminishes damage is unclear. However, a few obvious possibilities for the protective effects of L-deprenyl should be taken into consideration. First of all the regional differences in damage protection by L-deprenyl (4) is in agreement with MAO-B independent effects of L-deprenyl on free radical scavenger enzymes i.e. catalase and SOD (6,7). The ability of these scavenger enzymes to protect against ischemia induced damage has been described by numerous studies. Especially intrinsically increased expression of the scavenger enzymes had beneficial effects on damage outcome. For instance an increased SOD-expression in transgenic mice offered protection against radicals generated through ischemia (8,9) and/or MPTP (10).
- Published
- 1997
23. Pharmacokinetics and dosimetry of cobalt-55 and cobalt-57
- Author
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H M, Jansen, S, Knollema, L V, van der Duin, A T, Willemsen, A, Wiersma, E J, Franssen, F G, Russel, J, Korf, and A M, Paans
- Subjects
Adult ,Male ,Liver ,Urinary Bladder ,Animals ,Humans ,Tissue Distribution ,Cobalt Radioisotopes ,Rats, Wistar ,Radiation Dosage ,Radiometry ,Rats - Abstract
The isotopes 55Co and 57Co have been evaluated for PET and SPECT imaging in several clinical brain studies. For clinical application of cobalt, it is important to know the delivered radiation dose. The biodistribution of 55Co in both rat and humans after intravenous (bolus)-administration was studied. Based on pharmacokinetic data, radiation dose calculations according to the MIRD system are presented. By combining present measurements with literature data on 60CoCl2, the radiation dose delivered by 56CoCl2 (T1/2 78.8 days) and 57CoCl2 (T1/2 = 270 days) could be assessed.Whole-body Co-PET was performed in two healthy volunteers and one rat after intravenous injection of 37 and 3.7 MBq (1 resp. 0.1 mCi) 55Co, respectively. Blood samples were withdrawn during 300 min in humans. In seven rats the 55Co-biodistribution was determined by postmortem analysis. The residence time of the liver (critical organ) was determined in rats and humans. Blood partition-data of 55Co were assessed resulting in basic pharmacokinetic data in humans. Based on these kinetic data, radiation dose was calculated using the MIRD protocol.In both the humans and the rat, the liver and bladder retained the highest fractions of 55Co (about 50% resp. 40% of the administered dose). The liver residence time in humans was 8.6 hr. The free fraction 55Co in the human plasma was at maximum 12%. The total-body mean transit time was 152 min. The volume of the central compartment = 2.8 liter and the steady-state distribution volume = 48 liter.From these results, according to the WHO recommendations for class II studies, 22.2 MBq (0.6 mCi) 55Co and 14.8 MBq (0.4 mCi) 57Co (excluding any radionuclide contamination) can be used.
- Published
- 1996
24. l-Deprenyl Reduces Brain Damage in Rats Exposed to Transient Hypoxia-Ischemia
- Author
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S Knollema, Jakob Korf, Harold Hom, Walter Aukema, and Gert J. Ter Horst
- Subjects
Male ,CEREBRAL ISCHEMIA, TRANSIENT ,CUZN-SUPEROXIDE-DISMUTASE ,medicine.medical_treatment ,TRANSIENT ,(-)DEPRENYL ,Hippocampus ,Thalamus ,PARKINSONS-DISEASE ,Medicine ,REPERFUSION ,MONOAMINE OXIDASE INHIBITORS ,Hypoxia, Brain ,Saline ,FREE RADICALS ,Cerebral Cortex ,TRANSGENIC MICE ,biology ,Selegiline ,Brain ,Catalase ,Neuroprotective Agents ,Ischemic Attack, Transient ,Anesthesia ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,medicine.drug ,medicine.medical_specialty ,Ischemia ,Brain damage ,RATS ,MECHANISMS ,Superoxide dismutase ,CEREBRAL ISCHEMIA ,SUPEROXIDE DISMUTASE ,Prosencephalon ,Internal medicine ,INJURY ,Animals ,Rats, Wistar ,Advanced and Specialized Nursing ,business.industry ,Neurotoxicity ,Hypoxia (medical) ,medicine.disease ,Corpus Striatum ,LIFE ,Endocrinology ,NEUROTOXICITY ,biology.protein ,Neurology (clinical) ,business - Abstract
Background and Purpose l -Deprenyl (Selegiline) protects animal brains against toxic substances such as 1-methyl-1,2,3,6-tetrahydropyridine and 6-hydroxydopamine. Experiments were conducted to test whether l -deprenyl prevents or reduces cerebral damage in a transient hypoxia/ischemia rat model. Methods Rats were treated for 14 days with 2 mg/kg and 10 mg/kg l -deprenyl or saline. After surgery a 20-minute hypoxia/ischemia period was induced by simultaneous occlusion of the left common carotid artery and reduction of the percentage of oxygen in the gas mixture to 10%. Rats were killed 24 hours later. Silver staining was used to reveal damage in several brain regions. Results In the brain, both l -deprenyl dosages reduced damage up to 78% compared with the controls. Total brain damage was decreased from 23%-31% to 5%-9% with the l -deprenyl treatment (2 mg/kg: F 1.13 =6.956, P 1.13 =5.731, P l -deprenyl groups (2 mg/kg and 10 mg/kg, respectively) and the saline group (F 1.13 =14.870, P 1.13 =8.937, P =.01; respectively). In the thalamus, significant treatment effects were seen in the 2-mg/kg l -deprenyl group (F 1.13 =11.638, P 1.13 =8.347, P Conclusions The results show that l -deprenyl is effective as a prophylactic treatment for brain tissue when it is administered before hypoxia/ischemia. Mechanisms responsible for the observed protection remain unclear. The regional differences in damage, however, are in accordance with the reported regional increase in superoxide dismutase and catalase activities after l -deprenyl treatment, suggesting the involvement of free radicals and scavenger enzymes.
- Published
- 1995
25. Down-regulation of the hypothalamo-pituitary-adrenal axis reduces brain damage and number of seizures following hypoxia/ischaemia in rats
- Author
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Gert J. Ter Horst, Harm J. Krugers, S Knollema, Richard H.A. Kemper, and Jakob Korf
- Subjects
Male ,DIFFERENTIAL REGULATION ,HYPOTHALAMO-PITUITARY-ADRENAL AXIS ,Pituitary-Adrenal System ,Epilepsy ,chemistry.chemical_compound ,Corticosterone ,Adrenal Glands ,Hypoxia, Brain ,NEURONS ,General Neuroscience ,Organ Size ,DEGENERATION ,EXCITATORY AMINO-ACIDS ,Ischemic Attack, Transient ,HIPPOCAMPAL ASTROCYTES ,Brain Damage, Chronic ,medicine.symptom ,HYPOXIA ISCHEMIA ,MESSENGER-RNA ,ACUTE STROKE ,Glucocorticoid ,medicine.drug ,medicine.medical_specialty ,Kainic acid ,endocrine system ,Hypothalamo-Hypophyseal System ,Ischemia ,Down-Regulation ,Brain damage ,Thymus Gland ,Biology ,Central nervous system disease ,Seizures ,Internal medicine ,medicine ,SEIZURE ,Animals ,GLUCOCORTICOIDS ,Rats, Wistar ,Molecular Biology ,CORTISOL ,KAINIC ACID ,Hypoxia (medical) ,medicine.disease ,Rats ,Endocrinology ,chemistry ,Neurology (clinical) ,Developmental Biology - Abstract
Several reports suggest that the activity of the hypothalamo-pituitary-adrenal axis (HPA-axis) is increased following hypoxia/ischaemia and that this might be associated with increased neuronal vulnerability. The main goal of this study was to examine the effects of down-regulation of the HPA-axis on the hypoxia/ischaemia-induced (1) rise of plasma corticosterone levels, (2) seizures, and (3) brain damage. Down-regulation of the HPA-axis was induced by prolonged corticosterone treatment lasting until 24 h before hypoxia/ischaemia exposure. When compared to 8 days vehicle (sesame oil)-treated animals (CONT), 8 days daily corticosterone (40 mg/animal)-treated animals (CORT) showed significantly reduced adrenal-and thymus weight. Shortly after hypoxia/ischaemia plasma corticosterone levels in CORT animals were significantly reduced (17.30 micrograms/dl +/- 3.50) when compared to CONT animals (54.80 micrograms/dl +/- 7.78). This correlated with the brain damage which is expressed as the ratio between the damaged area and the total area. The total brain damage was significantly less in CORT-treated animals (28% +/- 11%) than in CONT animals (69% +/- 2%). Following hypoxia/ischaemia the number of seizures was significantly reduced in CORT animals (56 +/- 26) when compared to CONT animals (217 +/- 50). We conclude that prolonged corticosterone treatment resulting in down-regulation of the HPA-axis leads to (1) lower plasma corticosterone levels during hypoxia/ischaemia, (2) a reduction in brain damage following hypoxia/ischaemia, and (3) less hypoxia/ischaemia-induced seizures.
- Published
- 1995
26. Presence of human cytomegalovirus (HCMV) immediate early mRNA but not ppUL83 (lower matrix protein pp65) mRNA in polymorphonuclear and mononuclear leukocytes during active HCMV infection
- Author
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A. Grefte, M. C. Harmsen, M. van der Giessen, S. Knollema, W. J. van Son, and T. H. The
- Subjects
Human cytomegalovirus ,Transcription, Genetic ,medicine.drug_class ,Neutrophils ,viruses ,Granulocyte ,Monoclonal antibody ,Peripheral blood mononuclear cell ,Virus ,Monocytes ,Immediate-Early Proteins ,Viral Matrix Proteins ,Antigen ,Phagocytosis ,Virology ,medicine ,Humans ,RNA, Messenger ,Antigens, Viral ,In Situ Hybridization ,Phagocytes ,biology ,virus diseases ,RNA Probes ,medicine.disease ,Phosphoproteins ,Molecular biology ,Immunohistochemistry ,surgical procedures, operative ,medicine.anatomical_structure ,Cytomegalovirus Infections ,biology.protein ,Antibody ,Immediate early gene - Abstract
During an active human cytomegalovirus (HCMV) infection, leukocytes harbouring the HCMV lower matrix protein pp65 (ppUL83) are present in the peripheral blood and can be detected with the HCMV antigenaemia assay. In the present study, it was investigated whether the presence of pp65 in these cells was due to transcription of the virus genome or might be the result of uptake of this viral protein. Peripheral blood leukocytes of transplant recipients and AIDS patients with an active HCMV infection were investigated for the presence of HCMV immediate early (IE) antigen and pp65 using well characterized monoclonal antibodies, and for the presence of the corresponding mRNAs using non-radioactive in situ hybridization. Both mononuclear and polymorphonuclear cells were found to contain IE antigen and pp65. However, only mRNAs encoding IE antigen were found in these cells, whereas mRNAs encoding pp65 were not detected. In contrast, both IE antigen and pp65, as well as their corresponding mRNAs, were detected in the circulating late-stage HCMV-infected endothelial cells that were also present in the leukocyte fractions. These findings demonstrate that a restricted viral gene expression (transcription of IE genes) does occur in mononuclear and poly-morphonuclear leukocytes. However, the abundant presence of the early antigen pp65 without detectable presence of the corresponding mRNA in these cells strongly indicates uptake of this protein by the phagocytic leukocytes, rather than de novo synthesis.
- Published
- 1994
27. ALCAPA syndrome, a rare cause of sudden cardiac death.
- Author
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Rehman M, Braber T, Mouden M, Knollema S, and Güçlü A
- Published
- 2024
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- View/download PDF
28. Correction to: The incremental value of coronary artery calcium score in predicting long-term prognosis and defining the warranty period of normal adenosine stress-only myocardial perfusion imaging using CZT SPECT.
- Author
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Kamerman M, van Dijk JD, Timmer JR, Ottervanger JP, Knollema S, Jager PL, and Mouden M
- Published
- 2023
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- View/download PDF
29. The incremental value of coronary artery calcium score in predicting long-term prognosis and defining the warranty period of normal adenosine stress-only myocardial perfusion imaging using CZT SPECT.
- Author
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Kamerman M, van Dijk JD, Timmer JR, Ottervanger JP, Knollema S, Jager PL, and Mouden M
- Subjects
- Humans, Female, Middle Aged, Aged, Male, Calcium, Coronary Vessels diagnostic imaging, Retrospective Studies, Tomography, Emission-Computed, Single-Photon, Prognosis, Coronary Angiography methods, Myocardial Perfusion Imaging methods, Coronary Artery Disease diagnostic imaging
- Abstract
Background: Normal stress-only (SO) myocardial perfusion imaging (MPI) using SPECT reduces imaging time and radiation dose with a good prognosis. However, the long-term prognostic value of combining coronary artery calcium score (CACS) with SO MPI to determine the warranty period remains unknown. Hence, we assessed the incremental prognostic value of CACS and its impact on the warranty period of normal SO MPI using SPECT., Methods: We retrospectively included 1375 symptomatic patients without a history of coronary artery disease (CAD) and a normal SO MPI using adenosine who underwent simultaneous CAC scoring. Annual major adverse cardiac events (MACE) rates were calculated for CACS categories: 0, 1-399, 400-999, and ≥1000., Results: The mean age was 60.0 ± 11.8 years (66.9% female) with a median follow-up of 10.3 [IQR 9.6-10.9] years. The warranty period for annual MACE rate for normal SO SPECT extended the total follow-up time in years. MACE rate categorized by CAC categories demonstrated an increase in MACE rates with increasing CACS; CACS 0 and CACS 1-399 were associated with a 10-year warranty period, CACS 400-999 had a warranty period of 4 years and no warranty period could be given for CACS≥1000 (5.9 % at 1 year)., Conclusions: CACS as an adjunct to normal pharmacological SO MPI provides additional prognostic information and aids in determining a warranty period., (© 2023. The Author(s) under exclusive licence to American Society of Nuclear Cardiology.)
- Published
- 2023
- Full Text
- View/download PDF
30. Value of SiPM PET in myocardial perfusion imaging using Rubidium-82.
- Author
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Koenders SS, van Dalen JA, Jager PL, Knollema S, Timmer JR, Mouden M, Slump CH, and van Dijk JD
- Subjects
- Coronary Circulation physiology, Humans, Positron-Emission Tomography methods, Rubidium Radioisotopes, Tomography, X-Ray Computed, Coronary Artery Disease diagnostic imaging, Myocardial Perfusion Imaging methods
- Abstract
Background: PET scanners using silicon photomultipliers with digital readout (SiPM PET) have an improved temporal and spatial resolution compared to PET scanners using conventional photomultiplier tubes (PMT PET). However, the effect on image quality and visibility of perfusion defects in myocardial perfusion imaging (MPI) is unknown. Our aim was to determine the value of a SiPM PET scanner in MPI., Methods: We prospectively included 30 patients who underwent rest and regadenoson-induced stress Rubidium-82 (Rb-82) MPI on the D690 PMT PET (GE Healthcare) and within three weeks on the Vereos SiPM PET (Philips Healthcare). Two expert readers scored the image quality and assessed the existence of possible defects. In addition, interpreter's confidence, myocardial blood flow (MBF), and myocardial flow reserve (MFR) values were compared., Results: Image quality improved (P = 0.03) using the Vereos as compared to the D690. Image quality of the Vereos and the D690 was graded fair in 20% and 10%, good in 60% and 50%, and excellent in 20% and 40%, respectively. Defect interpretation and interpreter's confidence did not differ between the D690 and the Vereos (P > 0.50). There were no significant differences in rest MBF (P ≥ 0.29), stress MBF (P ≥ 0.11), and MFR (P ≥ 0.51)., Conclusion: SiPM PET provides an improved image quality in comparison with PMT PET. Defect interpretation, interpreter's confidence, and absolute blood flow measurements were comparable between both systems. SiPM PET is therefore a reliable technique for MPI using Rb-82., Trial Registration: ToetsingOnline NL63853.075.17. Registered 13 November, 2017., (© 2020. The Author(s).)
- Published
- 2022
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31. Performance of Digital PET Compared with High-Resolution Conventional PET in Patients with Cancer.
- Author
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Koopman D, van Dalen JA, Stevens H, Slump CH, Knollema S, and Jager PL
- Subjects
- Adult, Aged, Aged, 80 and over, Female, Fluorodeoxyglucose F18, Humans, Male, Middle Aged, Neoplasm Staging, Neoplasms pathology, Prospective Studies, Neoplasms diagnostic imaging, Positron-Emission Tomography methods
- Abstract
Recently introduced PET systems using silicon photomultipliers with digital readout (dPET) have an improved timing and spatial resolution, aiming at a better image quality than conventional PET (cPET) systems. We prospectively evaluated the performance of a dPET system in patients with cancer, as compared with high-resolution (HR) cPET imaging. Methods: After a single
18 F-FDG injection, 66 patients underwent dPET and cPET imaging in randomized order. We used HR reconstructions (2 × 2 × 2 mm voxels) for both scanners and determined SUVmax , SUVmean , lesion-to-background ratio (LBR), metabolic tumor volume (MTV), and lesion diameter in up to 518 F-FDG-positive lesions per patient. Furthermore, we counted the number of visible and measurable lesions on each PET scan. Two nuclear medicine specialists determined, in a masked manner, the TNM score from both image sets in 30 patients referred for initial staging. For all 66 patients, these specialists separately evaluated image quality (4-point scale) and determined the scan preference. Results: We included 238 lesions that were visible and measurable on both PET scans. For 27 patients, we found 37 additional lesions on dPET (41%) that were unmeasurable ( n = 14) or invisible ( n = 23) on cPET. Mean (±SD) SUVmean , SUVmax, LBR, and MTV on cPET were 5.2 ± 3.9, 6.9 ± 5.6, 5.0 ± 3.6, and 2,991 ± 13,251 mm3 , respectively. On dPET, SUVmean , SUVmax , and LBR increased by 24%, 23%, and 27%, respectively ( P < 0.001) whereas MTV decreased by 13% ( P < 0.001), compared with cPET. Visual analysis showed TNM upstaging with dPET in 13% of the patients (4/30). dPET images also had higher scores for quality ( P = 0.003) and were visually preferred in most cases (65%). Conclusion: dPET improved the detection of small lesions, upstaged the disease, and produced images that were visually preferred to those from HR cPET. More studies are necessary to confirm the superior diagnostic performance of dPET. Keywords: digital PET; conventional PET; FDG PET; lesion detection; cancer imaging., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)- Published
- 2020
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32. Does fractional flow reserve overestimate severity of LAD lesions?
- Author
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Yokota S, Borren NM, Ottervanger JP, Mouden M, Timmer JR, Knollema S, and Jager PL
- Subjects
- Aged, Female, Humans, Male, Middle Aged, Myocardial Perfusion Imaging, Prospective Studies, Tomography, Emission-Computed, Single-Photon, Coronary Stenosis physiopathology, Fractional Flow Reserve, Myocardial physiology
- Abstract
Background: Fractional Flow Reserve (FFR) is increasingly used to estimate the severity of coronary stenoses, prior to coronary revascularization. However, it has been suggested that FFR overestimates the severity of Left Anterior Descending (LAD) lesions. Our aim was to verify whether in patients without ischemia on Myocardial Perfusion Imaging, FFR of the LAD is more often abnormal in comparison to FFR of other coronary arteries., Methods: Prospective cohort study of consecutive patients who underwent FFR measurement because of persistent or worsening of angina complaints, within 6 months after normal Myocardial Perfusion Imaging. FFR measurements of a graft or diagonal branch were excluded. A FFR ≤ 0.80 denoted a functionally relevant stenosis., Results: In 133 patients, 167 FFR measurements were performed, of which 85 in the LAD. Mean age of the patients was 64.8 ± 10.5 years, 40% were women. There were no differences in baseline characteristics between patients undergoing LAD and non-LAD measurements. An abnormal FFR was observed in 35.3% of the LAD measurements, compared to 9.8% in the non-LAD measurements (P = 0.001). Also after adjusting for age and gender, the FFR remained more frequently abnormal in the LAD with OR 5.2 (95% CI 2.2 to 12.3). Of the abnormal FFR LAD measurements, 70% were visually considered non-obstructive on invasive angiography., Conclusions: In selected patients without ischemia on MPI, FFR measurement of the LAD is significantly more often abnormal. The majority of these patients has no obstructive lesions on invasive angiography. Possibly, FFR overestimates severity of LAD lesions, with risk of unnecessary revascularization.
- Published
- 2020
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33. SUV variability in EARL-accredited conventional and digital PET.
- Author
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Koopman D, Jager PL, Slump CH, Knollema S, and van Dalen JA
- Abstract
Background: A high SUV-reproducibility is crucial when different PET scanners are in use. We evaluated the SUV variability in whole-body FDG-PET scans of patients with suspected or proven cancer using an EARL-accredited conventional and digital PET scanner. In a head-to-head comparison we studied images of 50 patients acquired on a conventional scanner (cPET, Ingenuity TF PET/CT, Philips) and compared them with images acquired on a digital scanner (dPET, Vereos PET/CT, Philips). The PET scanning order was randomised and EARL-compatible reconstructions were applied. We measured SUV
mean , SUVpeak , SUVmax and lesion diameter in up to 5 FDG-positive lesions per patient. The relative difference ΔSUV between cPET and dPET was calculated for each SUV-parameter. Furthermore, we calculated repeatability coefficients, reflecting the 95% confidence interval of ΔSUV., Results: We included 128 lesions with an average size of 19 ± 14 mm. Average ΔSUVs were 6-8% with dPET values being higher for all three SUV-parameters (p < 0.001). ΔSUVmax was significantly higher than ΔSUVmean (8% vs. 6%, p = 0.002) and than ΔSUVpeak (8% vs. 7%, p = 0.03). Repeatability coefficients across individual lesions were 27% (ΔSUVmean and ΔSUVpeak ) and 33% (ΔSUVmax ) (p < 0.001)., Conclusions: With EARL-accredited conventional and digital PET, we found a limited SUV variability with average differences up to 8%. Furthermore, only a limited number of lesions showed a SUV difference of more than 30%. These findings indicate that EARL standardisation works., Trial Registration: This prospective study was registered on the 31th of October 2017 at ClinicalTrials.cov. URL: https://clinicaltrials.gov/ct2/show/NCT03457506?id=03457506&rank=1.- Published
- 2019
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34. Minimal rest activity for SPECT myocardial perfusion imaging in a one-day stress-first protocol.
- Author
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van Dijk JD, van Dalen JA, Knollema S, Mouden M, Ottervanger JP, and Jager PL
- Subjects
- Aged, Algorithms, Cadmium chemistry, Exercise Test, Female, Humans, Male, Middle Aged, Myocardium metabolism, Phantoms, Imaging, Prospective Studies, Radionuclide Imaging, Rest, Tellurium chemistry, Zinc chemistry, Heart diagnostic imaging, Image Processing, Computer-Assisted methods, Myocardial Perfusion Imaging, Tomography, Emission-Computed, Single-Photon
- Abstract
Purpose: Guidelines propose different rest-stress activity ratios (RSAR) for one-day stress-first SPECT myocardial perfusion imaging (MPI), but evidence is limited. Our aim was to determine and validate the minimal RSAR resulting in the same diagnostic outcome in one-day stress-first SPECT MPI., Methods: Forty-seven patients referred for rest after stress CZT-SPECT/CT MPI were prospectively included. Rest acquisitions were performed 3 h after stress. In addition to the stress and rest acquisitions, the first 22 patients underwent an additional acquisition prior to the rest injection to determine the remaining stress activity. Next, we simulated six RSARs varying from 1.0 to 3.5 in both patients and a phantom and compared the images to those using the reference RSAR of 4.0. Differences in summed difference score (SDS) >2 or ischemic defect interpretation were considered to significantly influence diagnostic outcome. After deriving the minimal RSAR, it was validated in 25 additional patients by comparing it to a RSAR of 4.0., Results: After 3 h only 26% of the stress activity was still present in the myocardium. SDS differences >2 were found in one (4%) patient using RSAR of 3.5, 2.5 and 2.0, in three (12%) using 1.5 and in five (20%) using SRAR of 1.0. These results were consistent with the phantom study showing SDS differences >2 for RSARs ≤1.5 and with the visual interpretation which showed an increased number of deviating scans for RSAR 1.0. Validating the RSAR of 2.0 resulted in a different SDS in one patient (SDS of 30 versus 11). Moreover, two scans were interpreted as ischemic instead of normal when using RSAR 2.0 and in two other scans the opposite was the case., Conclusions: A RSAR of 2.0 in one-day stress-first MPI SPECT seems sufficient to obtain accurate diagnostic outcomes and is therefore recommended to reduce radiation exposure.
- Published
- 2019
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35. Coronary calcium score influences referral for invasive coronary angiography after normal myocardial perfusion SPECT.
- Author
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Yokota S, Mouden M, Ottervanger JP, Engbers E, Jager PL, Timmer JR, and Knollema S
- Subjects
- Aged, Calcinosis pathology, Coronary Artery Disease diagnostic imaging, Female, Follow-Up Studies, Humans, Kaplan-Meier Estimate, Male, Middle Aged, Multivariate Analysis, Perfusion, Prognosis, Referral and Consultation, Calcium metabolism, Cardiology standards, Coronary Angiography, Heart diagnostic imaging, Myocardial Perfusion Imaging, Tomography, Emission-Computed, Single-Photon
- Abstract
Background: In patients with normal SPECT but persistent complaints, invasive angiography may exclude obstructive coronary disease. We assessed whether high coronary artery calcium (CAC) scores are associated with increased referral for invasive angiography following normal SPECT., Methods and Results: 2286 consecutive patients (mean age 60 ± 12, 39% male) with normal SPECT were assessed. All patients underwent simultaneous CAC scoring. Patients were categorized into four groups based on their CAC score: CAC = 0 (n = 694), CAC 1 to 100 (n = 891), CAC 101 to 400 (n = 368), and CAC >400 (n = 333). The decision to perform angiography was left to the discretion of treating physician. Follow-up angiography was confined to the first 60 days after SPECT. Occurrence of MACE (late revascularization, myocardial infarction or death) was recorded. Overall, 100 patients (4.4%) underwent early angiography with increasing rates in higher CAC score groups (1.0%, 2.6%, 8.4%, and 11.7%), respectively, P < .001). A CAC score >400 (OR 3.56, 95% CI 2.19 to 5.77, P < .001) was independently associated with referral to angiography. Similarly, CAC score >400 was an independent predictor for MACE (HR 9.26, 95% CI 5.06 to 16.93). Early angiography did not influence prognosis (HR 1.57, 95% CI 0.91 to 2.73)., Conclusions: CAC scoring impacts clinical decision-making and increases referral rates for invasive angiography after normal SPECT.
- Published
- 2019
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36. Anatomically and functionally relevant coronary stenoses in patients with normal single-photon emission computed tomography but persistent stable angina.
- Author
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Yokota S, Borren N, Mouden M, Timmer JR, Knollema S, Jager PL, and Ottervanger JP
- Subjects
- Aged, Analysis of Variance, Cohort Studies, Coronary Angiography methods, False Negative Reactions, Female, Follow-Up Studies, Humans, Male, Middle Aged, Netherlands, Reference Values, Retrospective Studies, Risk Assessment, Severity of Illness Index, Time Factors, Angina, Stable diagnosis, Angina, Stable epidemiology, Coronary Stenosis diagnostic imaging, Coronary Stenosis epidemiology, Fractional Flow Reserve, Myocardial physiology, Tomography, Emission-Computed, Single-Photon methods
- Abstract
Aims: Single-photon emission computed tomography (SPECT) is widely used for the assessment of coronary artery disease and for decision making regarding revascularization. Concerns about possible false negative findings exist. Our aim was to assess the prevalence of stenoses which are both functionally and anatomically significant in patients referred for invasive fractional flow reserve (FFR) measurements following a normal SPECT, because of persistent complaints., Methods and Results: One hundred and thirty-three consecutive patients with normal SPECT were included, with a total of 180 FFR measurements. Luminal narrowing of ≥70% (≥50% for left main) together with a FFR ≤0.80 denoted an anatomically and functionally significant coronary artery stenosis. Separate analyses were performed for FFR <0.75. Mean age of the patients was 65, 40% were women. Sixteen percent of the study population had both anatomically and functionally significant stenoses. Besides the use of nitrate, no differences in baseline characteristics, symptoms, coronary history, or pre-test likelihood could be identified for the prediction of functionally relevant obstructive coronary disease. If FFR <0.75 was used, only 7.5% of the patients had both anatomically and functionally significant stenoses., Conclusion: In patients with normal SPECT who undergo FFR measurements because of persistent complaints, the prevalence of stenoses which are both anatomically and functionally significant is low. This suggests that the prevalence of false-negative SPECT is (very) low.
- Published
- 2018
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37. Value of automatic patient motion detection and correction in myocardial perfusion imaging using a CZT-based SPECT camera.
- Author
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van Dijk JD, van Dalen JA, Mouden M, Ottervanger JP, Knollema S, Slump CH, and Jager PL
- Subjects
- Aged, Cadmium, Female, Humans, Male, Middle Aged, Pattern Recognition, Automated, Reference Standards, Reproducibility of Results, Respiration, Retrospective Studies, Software, Tellurium, Zinc, Image Processing, Computer-Assisted methods, Motion, Myocardial Perfusion Imaging, Tomography, Emission-Computed, Single-Photon instrumentation
- Abstract
Background: Correction of motion has become feasible on cadmium-zinc-telluride (CZT)-based SPECT cameras during myocardial perfusion imaging (MPI). Our aim was to quantify the motion and to determine the value of automatic correction using commercially available software., Methods and Results: We retrospectively included 83 consecutive patients who underwent stress-rest MPI CZT-SPECT and invasive fractional flow reserve (FFR) measurement. Eight-minute stress acquisitions were reformatted into 1.0- and 20-second bins to detect respiratory motion (RM) and patient motion (PM), respectively. RM and PM were quantified and scans were automatically corrected. Total perfusion deficit (TPD) and SPECT interpretation-normal, equivocal, or abnormal-were compared between the noncorrected and corrected scans. Scans with a changed SPECT interpretation were compared with FFR, the reference standard. Average RM was 2.5 ± 0.4 mm and maximal PM was 4.5 ± 1.3 mm. RM correction influenced the diagnostic outcomes in two patients based on TPD changes ≥7% and in nine patients based on changed visual interpretation. In only four of these patients, the changed SPECT interpretation corresponded with FFR measurements. Correction for PM did not influence the diagnostic outcomes., Conclusion: Respiratory motion and patient motion were small. Motion correction did not appear to improve the diagnostic outcome and, hence, the added value seems limited in MPI using CZT-based SPECT cameras.
- Published
- 2018
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38. Diagnostic implications of a small-voxel reconstruction for loco-regional lymph node characterization in breast cancer patients using FDG-PET/CT.
- Author
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Koopman D, van Dalen JA, Arkies H, Oostdijk AHJ, Francken AB, Bart J, Slump CH, Knollema S, and Jager PL
- Abstract
Background: We evaluated the diagnostic implications of a small-voxel reconstruction for lymph node characterization in breast cancer patients, using state-of-the-art FDG-PET/CT. We included 69 FDG-PET/CT scans from breast cancer patients. PET data were reconstructed using standard 4 × 4 × 4 mm
3 and small 2 × 2 × 2 mm3 voxels. Two hundred thirty loco-regional lymph nodes were included, of which 209 nodes were visualised on PET/CT. All nodes were visually scored as benign or malignant, and SUVmax and TBratio (=SUVmax /SUVbackground ) were measured. Final diagnosis was based on histological or imaging information. We determined the accuracy, sensitivity and specificity for both reconstruction methods and calculated optimal cut-off values to distinguish benign from malignant nodes., Results: Sixty-one benign and 169 malignant lymph nodes were included. Visual evaluation accuracy was 73% (sensitivity 67%, specificity 89%) on standard-voxel images and 77% (sensitivity 78%, specificity 74%) on small-voxel images (p = 0.13). Across malignant nodes visualised on PET/CT, the small-voxel score was more often correct compared with the standard-voxel score (89 vs. 76%, p < 0.001). In benign nodes, the standard-voxel score was more often correct (89 vs. 74%, p = 0.04). Quantitative data were based on the 61 benign and 148 malignant lymph nodes visualised on PET/CT. SUVs and TBratio were on average 3.0 and 1.6 times higher in malignant nodes compared to those in benign nodes (p < 0.001), on standard- and small-voxel PET images respectively. Small-voxel PET showed average increases in SUVmax and TBratio of typically 40% over standard-voxel PET. The optimal SUVmax cut-off using standard-voxels was 1.8 (sensitivity 81%, specificity 95%, accuracy 85%) while for small-voxels, the optimal SUVmax cut-off was 2.6 (sensitivity 78%, specificity 98%, accuracy 84%). Differences in accuracy were non-significant., Conclusions: Small-voxel PET/CT improves the sensitivity of visual lymph node characterization and provides a higher detection rate of malignant lymph nodes. However, small-voxel PET/CT also introduced more false-positive results in benign nodes. Across all nodes, differences in accuracy were non-significant. Quantitatively, small-voxel images require higher cut-off values. Readers have to adapt their reference standards.- Published
- 2018
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39. Digital PET compliance to EARL accreditation specifications.
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Koopman D, Groot Koerkamp M, Jager PL, Arkies H, Knollema S, Slump CH, Sanches PG, and van Dalen JA
- Abstract
Background: Our aim was to evaluate if a recently introduced TOF PET system with digital photon counting technology (Philips Healthcare), potentially providing an improved image quality over analogue systems, can fulfil EANM research Ltd (EARL) accreditation specifications for tumour imaging with FDG-PET/CT., Findings: We have performed a phantom study on a digital TOF PET system using a NEMA NU2-2001 image quality phantom with six fillable spheres. Phantom preparation and PET/CT acquisition were performed according to the European Association of Nuclear Medicine (EANM) guidelines. We made list-mode ordered-subsets expectation maximization (OSEM) TOF PET reconstructions, with default settings, three voxel sizes (4 × 4 × 4 mm
3 , 2 × 2 × 2 mm3 and 1 × 1 × 1 mm3 ) and with/without point spread function (PSF) modelling. On each PET dataset, mean and maximum activity concentration recovery coefficients (RCmean and RCmax ) were calculated for all phantom spheres and compared to EARL accreditation specifications. The RCs of the 4 × 4 × 4 mm3 voxel dataset without PSF modelling proved closest to EARL specifications. Next, we added a Gaussian post-smoothing filter with varying kernel widths of 1-7 mm. EARL specifications were fulfilled when using kernel widths of 2 to 4 mm., Conclusions: TOF PET using digital photon counting technology fulfils EARL accreditation specifications for FDG-PET/CT tumour imaging when using an OSEM reconstruction with 4 × 4 × 4 mm3 voxels, no PSF modelling and including a Gaussian post-smoothing filter of 2 to 4 mm.- Published
- 2017
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40. Prognostic Value of Myocardial Perfusion Imaging with a Cadmium-Zinc-Telluride SPECT Camera in Patients Suspected of Having Coronary Artery Disease.
- Author
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Engbers EM, Timmer JR, Mouden M, Knollema S, Jager PL, and Ottervanger JP
- Subjects
- Female, Follow-Up Studies, Humans, Male, Middle Aged, Prognosis, Cadmium, Coronary Artery Disease diagnostic imaging, Gamma Cameras, Myocardial Perfusion Imaging instrumentation, Tellurium, Tomography, Emission-Computed, Single-Photon instrumentation, Zinc
- Abstract
The prognostic value of myocardial perfusion imaging (MPI) with the cadmium-zinc-telluride (CZT) SPECT camera is not well established. Therefore, the aim of the current study was to evaluate the prognostic value of MPI performed with a CZT SPECT camera in a large cohort of patients suspected of having coronary artery disease. Methods: Consecutive symptomatic stable patients ( n = 4,057) without a history of coronary artery disease underwent CZT SPECT MPI. During a median follow-up of 2.4 y (25th-75th percentile, 1.7-3.4), patients were monitored for primary (nonfatal myocardial infarction and cardiac mortality) and secondary outcomes (late revascularization [>90 d after scanning] and primary outcome). Results: Patients with normal perfusion demonstrated low annual event rates (primary outcome, 0.2%; secondary outcome, 0.6%). Annual event rates increased with the extent of abnormality of myocardial perfusion. In patients with small ischemic perfusion defects, annual event rates were 0.7% and 2.8% for the primary and secondary outcome, respectively. In patients with moderate or large ischemic perfusion defects, these event rates were 1.2% and 4.3%, respectively. After multivariate analysis, the risk for events was significantly associated with the extent of ischemia (hazard ratio for small ischemic defects: 2.2, 95% confidence interval [CI], 0.9-5.9 and 4.6, 95% CI, 2.8-7.6, for primary and secondary outcomes, respectively; hazard ratio for moderate or large ischemic defects: 4.0, 95% CI, 1.5-10.5 and 12.1, 95% CI, 7.2-20.2, for primary and secondary outcomes, respectively). Conclusion: Our findings show that MPI acquired with a CZT SPECT camera provides excellent prognostic information, with low event rates in patients with normal myocardial perfusion. In patients with abnormal SPECT MPI, the extent of abnormality is independently associated with an increased risk of events., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)
- Published
- 2017
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41. Value of attenuation correction in stress-only myocardial perfusion imaging using CZT-SPECT.
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van Dijk JD, Mouden M, Ottervanger JP, van Dalen JA, Knollema S, Slump CH, and Jager PL
- Subjects
- Algorithms, Cadmium radiation effects, Equipment Design, Equipment Failure Analysis, Humans, Middle Aged, Netherlands epidemiology, Observer Variation, Prevalence, Prognosis, Radionuclide Imaging instrumentation, Radionuclide Imaging methods, Reproducibility of Results, Sensitivity and Specificity, Survival Rate, Tellurium radiation effects, Zinc radiation effects, Artifacts, Exercise Test instrumentation, Image Enhancement methods, Myocardial Ischemia diagnostic imaging, Myocardial Ischemia mortality, Myocardial Perfusion Imaging instrumentation, Tomography, Emission-Computed, Single-Photon instrumentation
- Abstract
Background: Attenuation correction (AC) improves the diagnostic outcome of stress-only myocardial perfusion imaging (MPI) using conventional SPECT. Our aim was to determine the value of AC using a cadmium zinc telluride-based (CZT)-SPECT camera., Methods and Results: We retrospectively included 107 consecutive patients who underwent stress-optional rest MPI CZT-SPECT/CT. Next, we created three types of images for each patient; (1) only displaying reconstructed data without the CT-based AC (NC), (2) only displaying AC, and (3) with both NC and AC (NC + AC). Next, two experienced physicians visually interpreted these 321 randomized images as normal, equivocal, or abnormal. Image outcome was compared with all hard events over a mean follow-up time of 47.7 ± 9.8 months. The percentage of images interpreted as normal increased from 45% using the NC images to 72% using AC and to 67% using NC + AC images (P < .001). Hard event hazard ratios for images interpreted as normal were not different between using NC and AC (1.01, P = .99), or NC and NC + AC images (0.97, P = .97)., Conclusions: AC lowers the need for additional rest imaging in stress-first MPI using CZT-SPECT, while long-term patient outcome remained identical. Use of AC reduces the need for additional rest imaging, decreasing the mean effective dose by up to 1.2 mSv.
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- 2017
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42. Changes in cardiovascular medication after coronary artery calcium scanning and normal single photon emission computed tomography myocardial perfusion imaging in symptomatic patients.
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Engbers EM, Timmer JR, Mouden M, Knollema S, Jager PL, and Ottervanger JP
- Subjects
- Aspirin therapeutic use, Female, Fibrinolytic Agents therapeutic use, Humans, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Male, Middle Aged, Retrospective Studies, Tomography, Emission-Computed, Single-Photon, Calcinosis diagnostic imaging, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease drug therapy, Coronary Vessels diagnostic imaging
- Abstract
The impact of coronary artery calcium (CAC) scoring on subsequent changes in cardiovascular medication use in symptomatic patients with normal myocardial perfusion imaging (MPI) findings is not well established. The aim of the current study was to evaluate changes in aspirin and statin use in patients suspected for coronary artery disease after CAC scoring and normal single photon emission computed tomography (SPECT) MPI., Methods: In the current study, 1,033 stable symptomatic patients without a known history of coronary artery disease with normal SPECT MPI who underwent concomitant CAC scoring were included. All patients had a clinical indication for imaging, mainly atypical chest pain and dyspnea, and were referred from the outpatient clinic of our hospital. Data regarding posttest medication change (either starting or discontinuation of aspirin and statin therapy at the subsequent outpatient visit) were retrospectively collected. Patients were categorized into 4 groups based on their CAC score., Results: Mean age of the patients was 61±11 years and 39% were male. At baseline, 35% of the patients used aspirin and 39% used statin. In patients with CAC scores 0, 1-99, 100-399, and ≥400, aspirin was started in 1%, 4%, 9%, and 9%, respectively, and statin was started in 0%, 7%, 18%, and 24% of the patients, respectively (P<.001). Aspirin was discontinued in 19%, 11%, 7%, and 1% and statin was discontinued in 8%, 6%, 2%, and 0% (P<.001) of the patients in these respective CAC score categories. After correction for differences in risk factors and baseline medication use, increased CAC was independently associated with posttest aspirin (odds ratio 4.6, 11.2, and 27.1 for CAC scores 1-99, 100-399, and ≥400, respectively; P<.001) and statin use (odds ratio 4.4, 19.4, and 60.9 for CAC scores 1-99, 100-399, and ≥400, respectively; P<.001)., Conclusions: Higher CAC scores are associated with the initiation of aspirin and statin therapy in patients with normal SPECT MPI. In patients with lower CAC scores, discontinuation of cardioprotective medication is more likely. CAC score is independently associated with posttest statin and aspirin use., (Copyright © 2017 Elsevier Inc. All rights reserved.)
- Published
- 2017
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43. Sequential SPECT/CT imaging for detection of coronary artery disease in a large cohort: evaluation of the need for additional imaging and radiation exposure.
- Author
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Engbers EM, Timmer JR, Ottervanger JP, Mouden M, Oostdijk AHJ, Knollema S, and Jager PL
- Subjects
- Disease Progression, Female, Humans, Longitudinal Studies, Male, Middle Aged, Needs Assessment, Netherlands epidemiology, Prevalence, Risk Factors, Subtraction Technique statistics & numerical data, Utilization Review, Coronary Artery Disease diagnostic imaging, Coronary Artery Disease epidemiology, Medical Overuse statistics & numerical data, Radiation Exposure prevention & control, Radiation Exposure statistics & numerical data, Referral and Consultation statistics & numerical data, Single Photon Emission Computed Tomography Computed Tomography statistics & numerical data
- Abstract
Background: Performing both single photon emission computerized tomography (SPECT) and coronary computed tomography angiography (CCTA) in patients suspected for coronary artery disease (CAD) leads to increased radiation exposure. We evaluated the need for additional imaging and following implications for radiation exposure of a sequential SPECT/computed tomography (CT) algorithm., Methods and Results: 5018 consecutive patients without history of CAD were referred for stress-first SPECT and coronary artery calcium (CAC) scoring. If stress SPECT was abnormal, additional rest SPECT and, if feasible, CCTA were acquired. Stress SPECT was normal in 2617 patients (52%). CCTA was not performed in 1289 of the 2401 patients referred for additional imaging (54%), mainly because of severe CAC (47%) or fast/irregular heart rate (22%). 642 patients with abnormal SPECT underwent CCTA, which excluded significant CAD in 378 patients (59%). Mean radiation dose was 4.5 ± 0.3 mSv for stress-only imaging and 13.2 ± 3.3 mSv for additional imaging (P < 0.001)., Conclusions: Half of the patients do not require additional imaging in our sequential SPECT/CT algorithm, which is accompanied with low radiation exposure. CCTA cannot be performed in half of the patients who undergo additional imaging because of (relative) contra-indications. CCTA is able to correct for false-positive SPECT findings in our algorithm.
- Published
- 2017
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44. Sequential SPECT/CT imaging starting with stress SPECT in patients with left bundle branch block suspected for coronary artery disease.
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Engbers EM, Timmer JR, Mouden M, Knollema S, Jager PL, and Ottervanger JP
- Subjects
- Aged, Bundle-Branch Block etiology, Bundle-Branch Block physiopathology, Coronary Angiography, Coronary Artery Disease diagnosis, Exercise Test, Feasibility Studies, Female, Humans, Male, Middle Aged, Prospective Studies, Bundle-Branch Block diagnosis, Coronary Artery Disease complications, Coronary Vessels diagnostic imaging, Tomography, Emission-Computed, Single-Photon methods
- Abstract
Objectives: To investigate the impact of left bundle branch block (LBBB) on sequential single photon emission computed tomography (SPECT)/ CT imaging starting with stress-first SPECT., Methods: Consecutive symptomatic low- to intermediate-risk patients without a history of coronary artery disease (CAD) referred for SPECT/CT were included from an observational registry. If stress SPECT was abnormal, additional rest SPECT and, if feasible, coronary CT angiography (CCTA) were acquired., Results: Of the 5,018 patients, 218 (4.3 %) demonstrated LBBB. Patients with LBBB were slightly older than patients without LBBB (65±12 vs. 61±11 years, p<0.001). Stress SPECT was more frequently abnormal in patients with LBBB (82 % vs. 46 %, p<0.001). After reviewing stress and rest images, SPECT was normal in 43 % of the patients with LBBB, compared to 77 % of the patients without LBBB (p<0.001). Sixty-four of the 124 patients with LBBB and abnormal stress-rest SPECT underwent CCTA (52 %), which could exclude obstructive CAD in 46 of the patients (72 %)., Conclusions: Sequential SPECT/CT imaging starting with stress SPECT is not the optimal imaging protocol in patients with LBBB, as the majority of these patients have potentially false-positive stress SPECT. First-line testing using CCTA may be more appropriate in low- to intermediate-risk patients with LBBB., Key Points: • Stress-first SPECT imaging is attractive if many patients demonstrate normal stress perfusion. • The majority of left bundle branch block patients have abnormal stress-first SPECT. • Coronary CT excluded obstructive CAD in many LBBB patients with abnormal SPECT. • Stress-first SPECT imaging is not the optimal imaging protocol in LBBB patients. • In LBBB patients imaging with initial coronary CT may be more appropriate.
- Published
- 2017
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45. Impact of new X-ray technology on patient dose in pacemaker and implantable cardioverter defibrillator (ICD) implantations.
- Author
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van Dijk JD, Ottervanger JP, Delnoy PP, Lagerweij MC, Knollema S, Slump CH, and Jager PL
- Subjects
- Aged, Equipment Design, Equipment Failure Analysis, Female, Humans, Male, Netherlands epidemiology, Prosthesis Implantation methods, Prosthesis Implantation statistics & numerical data, Radiation Dosage, Radiation Exposure analysis, Radiation Exposure prevention & control, Radiation Protection methods, Radiation Protection statistics & numerical data, Retrospective Studies, Defibrillators, Implantable statistics & numerical data, Pacemaker, Artificial statistics & numerical data, Radiation Exposure statistics & numerical data, Radiography, Interventional instrumentation, Radiography, Interventional statistics & numerical data
- Abstract
Purpose: New X-ray technology providing new image processing techniques may reduce radiation exposure. The aim of this study was to quantify this radiation exposure reduction for patients during pacemaker and implantable cardioverter defibrillator (ICD) implantation., Methods: In this retrospective study, 1185 consecutive patients who had undergone de novo pacemaker or ICD implantation during a 2-year period were included. All implantations in the first year were performed using the reference technology (Allura Xper), whereas in the second year, the new X-ray technology (AlluraClarity) was used. Radiation exposure, expressed as the dose area product (DAP), was compared between the two time periods to determine the radiation exposure reduction for pacemaker and ICD implantations without cardiac resynchronization therapy (CRT) and with CRT. Procedure duration and contrast volume were used as measures to compare complexity and image quality., Results: The study population consisted of 591 patients who had undergone an implantation using the reference technology, and 594 patients with the new X-ray technology. The two groups did not differ in age, gender, or body mass index. The DAP decreased with 69 % from 16.4 ± 18.5 to 5.2 ± 6.6 Gy cm
2 for the non-CRT implantations (p < 0.001). The DAP decreased with 75 % from 72.1 ± 60.0 to 17.8 ± 17.4 Gy cm2 for the CRT implantations (p < 0.001). Nevertheless, procedure duration and contrast volume did not differ when using the new technology (p = 0.09 and p = 0.20, respectively)., Conclusions: Introduction of new X-ray technology resulted in a radiation exposure reduction of more than 69 % for patients during pacemaker and ICD implantation while image quality was unaffected., Competing Interests: The authors declare that they have no conflict of interests.- Published
- 2017
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46. Impact of Gender on the Prognostic Value of Coronary Artery Calcium in Symptomatic Patients With Normal Single-Photon Emission Computed Tomography Myocardial Perfusion.
- Author
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Engbers EM, Timmer JR, Ottervanger JP, Mouden M, Knollema S, and Jager PL
- Subjects
- Age Factors, Calcinosis diagnosis, Coronary Artery Disease diagnosis, Coronary Vessels metabolism, Female, Follow-Up Studies, Humans, Incidence, Male, Middle Aged, Netherlands epidemiology, Prognosis, Prospective Studies, Risk Factors, Calcinosis epidemiology, Calcium metabolism, Coronary Artery Disease epidemiology, Coronary Vessels diagnostic imaging, Myocardial Perfusion Imaging methods, Tomography, Emission-Computed, Single-Photon methods
- Abstract
The coronary artery calcium (CAC) score provides independent prognostic value on top of single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). We sought to determine whether the prognostic value of the CAC score in patients with normal SPECT MPI is gender specific. We studied 3,705 consecutive symptomatic patients without a history of coronary artery disease with normal SPECT MPI. All patients underwent concomitant CAC scoring, which was categorized as CAC score 0, 1 to 99, 100 to 399, 400 to 999, or ≥1,000. Major adverse cardiac events were defined as revascularization, nonfatal myocardial infarction, or all-cause mortality. The median CAC score was 9 in women (interquartile range 0 to 113) and 47 in men (interquartile range 1 to 307, p <0.001). The annual event rate was lower in women than in men (1.6% and 2.7%, respectively, p <0.001). When stratified by CAC score, annual event rates were similar (for women and men, respectively: CAC score 0, 0.6% and 0.5%, p = 0.95; CAC score 1 to 99, 0.9% and 1.2%, p = 0.45; CAC score 100 to 399, 2.7% and 3.8%, p = 0.23; CAC score 400 to 999, 3.8% and 5.3%, p = 0.34; CAC score ≥1,000, 8.4% and 8.7%, p = 0.99). The CAC score was an independent predictor of major adverse cardiac events in both genders (CAC score ≥1,000: hazard ratio for women 8.5, 95% confidence interval 4.0 to 18.1; hazard ratio for men 14.8, 95% confidence interval 5.3 to 41.1). In conclusion, risk for events is similar for both genders when stratified by CAC score, wherein a high CAC score carries a high risk for events despite normal SPECT MPI. Our findings do not reveal a gender-specific prognostic value of the CAC score., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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47. Technical note: how to determine the FDG activity for tumour PET imaging that satisfies European guidelines.
- Author
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Koopman D, van Osch JA, Jager PL, Tenbergen CJ, Knollema S, Slump CH, and van Dalen JA
- Abstract
Background: For tumour imaging with PET, the literature proposes to administer a patient-specific FDG activity that depends quadratically on a patient's body weight. However, a practical approach on how to implement such a protocol in clinical practice is currently lacking. We aimed to provide a practical method to determine a FDG activity formula for whole-body PET examinations that satisfies both the EANM guidelines and this quadratic relation., Results: We have developed a methodology that results in a formula describing the patient-specific FDG activity to administer. A PET study using the NEMA NU-2001 image quality phantom forms the basis of our method. This phantom needs to be filled with 2.0 and 20.0 kBq FDG/mL in the background and spheres, respectively. After a PET acquisition of 10 min, a reconstruction has to be performed that results in sphere recovery coefficients (RCs) that are within the specifications as defined by the EANM Research Ltd (EARL). By performing reconstructions based on shorter scan durations, the minimal scan time per bed position (T min) needs to be extracted using an image coefficient of variation (COV) of 15 %. At T min, the RCs should be within EARL specifications as well. Finally, the FDG activity (in MBq) to administer can be described by [Formula: see text] with c a constant that is typically 0.0533 (MBq/kg(2)), w the patient's body weight (in kg), and t the scan time per bed position that is chosen in a clinical setting (in seconds). We successfully demonstrated this methodology using a state-of-the-art PET/CT scanner., Conclusions: We provide a practical method that results in a formula describing the FDG activity to administer to individual patients for whole-body PET examinations, taking into account both the EANM guidelines and a quadratic relation between FDG activity and patient's body weight. This formula is generally applicable to any PET system, using a specified image reconstruction and scan time per bed position.
- Published
- 2016
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48. Visual estimation of coronary calcium on computed tomography for attenuation correction.
- Author
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Engbers EM, Timmer JR, Mouden M, Jager PL, Knollema S, Oostdijk AH, and Ottervanger JP
- Subjects
- Aged, Coronary Artery Disease physiopathology, Coronary Circulation, Coronary Vessels physiopathology, Female, Humans, Male, Middle Aged, Observer Variation, Predictive Value of Tests, Prognosis, Reproducibility of Results, Severity of Illness Index, Vascular Calcification physiopathology, Computed Tomography Angiography, Coronary Angiography methods, Coronary Artery Disease diagnostic imaging, Coronary Vessels diagnostic imaging, Multidetector Computed Tomography, Myocardial Perfusion Imaging methods, Single Photon Emission Computed Tomography Computed Tomography, Vascular Calcification diagnostic imaging
- Abstract
Background: The coronary calcium score (CCS) provides independent diagnostic and prognostic information on top of myocardial perfusion imaging (MPI) in patients suspected for coronary artery disease, but requires an additional computed tomography (CT) scan., Objective: We investigated the accuracy and inter-reader reproducibility of visual estimation of the CCS on the CT used for attenuation correction., Methods: 250 patients undergoing single photon emission computed tomography MPI and Agatston CCS were included. The CCS was also visually estimated on the CT for attenuation correction by two separate readers blinded to the Agatston CCS, and was categorized into a six-point scale (0, 1-10, 11-100, 101-400, 401-1000 and > 1000)., Results: The median Agatston CCS was 82 [25th-75th percentile: 0-562], with a range from 0 to 7287. Of the visually estimated CCS, 60% (reader 1) and 65% (reader 2) were classified correctly into the 6 categories. 93% (reader 1) and 88% (reader 2) of the visually estimated CCS did not vary by more than one category from the Agatston CCS. The intraclass correlation coefficient for agreement between the Agatston CCS and the visually estimated CCS was 0.95 for reader 1 and 0.94 for reader 2. The intraclass correlation coefficient for inter-reader reproducibility of the visually estimated CCS was 0.96., Conclusion: The CCS can be accurately estimated on the CT for attenuation correction, as high agreement is demonstrated with the Agatston CCS and inter-reader reproducibility is excellent. If no traditional Agatston CCS is performed, the degree of atherosclerosis should be assessed by means of estimating CCS on the CT for attenuation correction., (Copyright © 2016 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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49. Prognostic Value of Coronary Artery Calcium Scoring in Addition to Single-Photon Emission Computed Tomographic Myocardial Perfusion Imaging in Symptomatic Patients.
- Author
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Engbers EM, Timmer JR, Ottervanger JP, Mouden M, Knollema S, and Jager PL
- Subjects
- Aged, Cause of Death, Coronary Artery Disease mortality, Coronary Artery Disease physiopathology, Coronary Artery Disease therapy, Coronary Vessels physiopathology, Female, Humans, Male, Middle Aged, Myocardial Infarction mortality, Myocardial Revascularization, Netherlands, Predictive Value of Tests, Prognosis, Prospective Studies, Registries, Reproducibility of Results, Risk Factors, Severity of Illness Index, Time Factors, Vascular Calcification mortality, Vascular Calcification physiopathology, Vascular Calcification therapy, Computed Tomography Angiography, Coronary Angiography methods, Coronary Artery Disease diagnostic imaging, Coronary Circulation, Coronary Vessels diagnostic imaging, Myocardial Perfusion Imaging methods, Single Photon Emission Computed Tomography Computed Tomography, Vascular Calcification diagnostic imaging
- Abstract
Background: The prognostic value of coronary artery calcium (CAC) scoring on top of myocardial perfusion imaging with single-photon emission computed tomography (SPECT) in patients suspected for coronary artery disease is not well established., Methods and Results: Four thousand eight hundred ninety-seven symptomatic patients without a history of coronary artery disease referred for SPECT and CAC scoring were included. Major adverse cardiac events (MACEs) were defined as late revascularization (>90 days after scanning), nonfatal myocardial infarction, and all-cause mortality. The frequency of abnormal SPECT increased with higher CAC scores, from 12% in patients with CAC scores of 0 to 19%, 32%, 37%, and 50% among those with CAC scores 1 to 99, 100 to 399, 400 to 999, and ≥1000, respectively (P<0.001). During a median follow-up of 940 days (25th to 75th percentile, 581-1377), a total of 278 MACEs were observed. Overall incidence of MACE was 2.3% per year. A stepwise increase of MACE was present with increasing CAC scores, both in patients with normal SPECT (annual event rate CAC score 0: 0.6%; CAC score ≥1000: 5.5%) and abnormal SPECT (annual event rate CAC score 0: 0.4%; CAC score ≥1000: 7.6%). After multivariate analysis, both SPECT and CAC score were independent predictors of MACE (CAC score ≥1000: hazard ratio, 7.7; P<0.001 and large perfusion defect on SPECT: hazard ratio, 3.7; P<0.001)., Conclusions: CAC score and SPECT are independent predictors of MACE in patients suspected for coronary artery disease. Our findings strongly support performing a CAC score in addition to SPECT in symptomatic patients to better define the risk of events during follow-up., (© 2016 American Heart Association, Inc.)
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- 2016
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50. A practical approach for a patient-tailored dose protocol in coronary CT angiography using prospective ECG triggering.
- Author
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van Dijk JD, Huizing ED, Jager PL, Ottervanger JP, Knollema S, Slump CH, and van Dalen JA
- Subjects
- Adult, Aged, Artifacts, Female, Humans, Male, Middle Aged, Predictive Value of Tests, Radiation Exposure, Reproducibility of Results, Retrospective Studies, Cardiac-Gated Imaging Techniques, Coronary Angiography, Coronary Artery Disease diagnostic imaging, Coronary Vessels diagnostic imaging, Electrocardiography, Radiation Dosage, Tomography, X-Ray Computed
- Abstract
To derive and validate a practical patient-specific dose protocol to obtain an image quality, expressed by the image noise, independent of patients' size and a better radiation dose justification in coronary CT angiography (CCTA) using prospective ECG triggering. 43 patients underwent clinically indicated CCTA. The image noise, defined as the standard deviation of pixel attenuation values in a homogeneous region in the liver, was determined in all scans. Subsequently, this noise was normalized to the radiation exposure. Next, three patient-specific parameters, body weight, body mass index and mass per length (MPL), were tested for the best correlation with normalized image noise. From these data, a new dose protocol to provide a less variable image noise was derived and subsequently validated in 84 new patients. The normalized image noise increased for heavier patients for all patients' specific parameters (p < 0.001). MPL correlated best with the normalized image noise and was selected for dose protocol optimization. This new protocol resulted in image noise levels independent of patients' MPL (p = 0.28). A practical method to obtain CCTA images with noise levels independent of patients' MPL was derived and validated. It results in a less variable image quality and better radiation exposure justification and can also be used for CT scanners from other vendors.
- Published
- 2016
- Full Text
- View/download PDF
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