127 results on '"Neubauer, Stefan"'
Search Results
2. Synergistic effect on cardiac energetics by targeting the creatine kinase system: in vivo application of high-resolution 31P-CMRS in the mouse
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Maguire, Mahon L., McAndrew, Debra J., Lake, Hannah A., Ostrowski, Philip J., Zervou, Sevasti, Neubauer, Stefan, Lygate, Craig A., and Schneider, Jurgen E.
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- 2023
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3. Editorial Expression of Concern: Splenic T1-mapping: a novel quantitative method for assessing adenosine stress adequacy for cardiovascular magnetic resonance
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Liu, Alexander, Wijesurendra, Rohan S., Ariga, Rina, Mahmod, Masliza, Levelt, Eylem, Greiser, Andreas, Petrou, Mario, Krasopoulos, George, Forfar, John C., Kharbanda, Rajesh K., Channon, Keith M., Neubauer, Stefan, Piechnik, Stefan K., and Ferreira, Vanessa M.
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- 2023
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4. Society for Cardiovascular Magnetic Resonance (SCMR) guidelines for reporting cardiovascular magnetic resonance examinations
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Hundley, W. Gregory, Bluemke, David A., Bogaert, Jan, Flamm, Scott D., Fontana, Marianna, Friedrich, Matthias G., Grosse-Wortmann, Lars, Karamitsos, Theodoros D., Kramer, Christopher M., Kwong, Raymond Y., McConnell, Michael, Nagel, Eike, Neubauer, Stefan, Nijveldt, Robin, Pennell, Dudley J., Petersen, Steffen E., Raman, Subha V., and van Rossum, Albert
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- 2022
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5. Right ventricular function declines prior to left ventricular ejection fraction in hypertrophic cardiomyopathy
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Mahmod, Masliza, Raman, Betty, Chan, Kenneth, Sivalokanathan, Sanjay, Smillie, Robert W., Samat, Azlan H. Abd, Ariga, Rina, Dass, Sairia, Ormondroyd, Elizabeth, Watkins, Hugh, and Neubauer, Stefan
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- 2022
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6. Demographic, multi-morbidity and genetic impact on myocardial involvement and its recovery from COVID-19: protocol design of COVID-HEART—a UK, multicentre, observational study
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Gorecka, Miroslawa, McCann, Gerry P., Berry, Colin, Ferreira, Vanessa M., Moon, James C., Miller, Christopher A., Chiribiri, Amedeo, Prasad, Sanjay, Dweck, Marc R., Bucciarelli-Ducci, Chiara, Dawson, Dana, Fontana, Marianna, Macfarlane, Peter W., McConnachie, Alex, Neubauer, Stefan, and Greenwood, John P.
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- 2021
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7. Cardiovascular magnetic resonance reference values of mitral and tricuspid annular dimensions: the UK Biobank cohort
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Ricci, Fabrizio, Aung, Nay, Gallina, Sabina, Zemrak, Filip, Fung, Kenneth, Bisaccia, Giandomenico, Paiva, Jose Miguel, Khanji, Mohammed Y., Mantini, Cesare, Palermi, Stefano, Lee, Aaron M., Piechnik, Stefan K., Neubauer, Stefan, and Petersen, Steffen E.
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- 2021
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8. Left atrial 4D flow cardiovascular magnetic resonance: a reproducibility study in sinus rhythm and atrial fibrillation
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Spartera, Marco, Pessoa-Amorim, Guilherme, Stracquadanio, Antonio, Von Ende, Adam, Fletcher, Alison, Manley, Peter, Neubauer, Stefan, Ferreira, Vanessa M., Casadei, Barbara, Hess, Aaron T., and Wijesurendra, Rohan S.
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- 2021
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9. Incremental value of left atrial booster and reservoir strain in predicting atrial fibrillation in patients with hypertrophic cardiomyopathy: a cardiovascular magnetic resonance study
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Raman, Betty, Smillie, Robert W., Mahmod, Masliza, Chan, Kenneth, Ariga, Rina, Nikolaidou, Chrysovalantou, Ormondroyd, Elizabeth, Thomson, Kate, Harper, Andrew R., Tan, Gifford, Lewandowski, Adam J., Rodriguez Bajo, Fernando, Wicks, Eleanor C., Casadei, Barbara, Watkins, Hugh, and Neubauer, Stefan
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- 2021
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10. Cardiac MRI improves cardiovascular risk stratification in hazardous occupations
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Holdsworth, David A., Parsons, Iain T., Chamley, Rebecca, Britton, Joseph, Pavitt, Christopher, Baksi, A. John, Neubauer, Stefan, d’Arcy, Joanna, and Nicol, Edward D.
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- 2019
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11. Right ventricular shape and function: cardiovascular magnetic resonance reference morphology and biventricular risk factor morphometrics in UK Biobank
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Mauger, Charlène, Gilbert, Kathleen, Lee, Aaron M., Sanghvi, Mihir M., Aung, Nay, Fung, Kenneth, Carapella, Valentina, Piechnik, Stefan K., Neubauer, Stefan, Petersen, Steffen E., Suinesiaputra, Avan, and Young, Alistair A.
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- 2019
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12. Measuring inorganic phosphate and intracellular pH in the healthy and hypertrophic cardiomyopathy hearts by in vivo 7T 31P-cardiovascular magnetic resonance spectroscopy
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Valkovič, Ladislav, Clarke, William T., Schmid, Albrecht I., Raman, Betty, Ellis, Jane, Watkins, Hugh, Robson, Matthew D., Neubauer, Stefan, and Rodgers, Christopher T.
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- 2019
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13. Automated quality control in image segmentation: application to the UK Biobank cardiovascular magnetic resonance imaging study
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Robinson, Robert, Valindria, Vanya V., Bai, Wenjia, Oktay, Ozan, Kainz, Bernhard, Suzuki, Hideaki, Sanghvi, Mihir M., Aung, Nay, Paiva, José Miguel, Zemrak, Filip, Fung, Kenneth, Lukaschuk, Elena, Lee, Aaron M., Carapella, Valentina, Kim, Young Jin, Piechnik, Stefan K., Neubauer, Stefan, Petersen, Steffen E., Page, Chris, Matthews, Paul M., Rueckert, Daniel, and Glocker, Ben
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- 2019
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14. The interplay between metabolic alterations, diastolic strain rate and exercise capacity in mild heart failure with preserved ejection fraction: a cardiovascular magnetic resonance study
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Mahmod, Masliza, Pal, Nikhil, Rayner, Jennifer, Holloway, Cameron, Raman, Betty, Dass, Sairia, Levelt, Eylem, Ariga, Rina, Ferreira, Vanessa, Banerjee, Rajarshi, Schneider, Jurgen E., Rodgers, Christopher, Francis, Jane M., Karamitsos, Theodoros D., Frenneaux, Michael, Ashrafian, Houman, Neubauer, Stefan, and Rider, Oliver
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- 2018
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15. Automated cardiovascular magnetic resonance image analysis with fully convolutional networks
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Bai, Wenjia, Sinclair, Matthew, Tarroni, Giacomo, Oktay, Ozan, Rajchl, Martin, Vaillant, Ghislain, Lee, Aaron M., Aung, Nay, Lukaschuk, Elena, Sanghvi, Mihir M., Zemrak, Filip, Fung, Kenneth, Paiva, Jose Miguel, Carapella, Valentina, Kim, Young Jin, Suzuki, Hideaki, Kainz, Bernhard, Matthews, Paul M., Petersen, Steffen E., Piechnik, Stefan K., Neubauer, Stefan, Glocker, Ben, and Rueckert, Daniel
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- 2018
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16. Test-retest variability of left ventricular 4D flow cardiovascular magnetic resonance measurements in healthy subjects
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Stoll, Victoria M., Loudon, Margaret, Eriksson, Jonatan, Bissell, Malenka M., Dyverfeldt, Petter, Ebbers, Tino, Myerson, Saul G., Neubauer, Stefan, Carlhäll, Carl- Johan, and Hess, Aaron T.
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- 2018
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17. Splenic T1-mapping: a novel quantitative method for assessing adenosine stress adequacy for cardiovascular magnetic resonance
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Liu, Alexander, Wijesurendra, Rohan S., Ariga, Rina, Mahmod, Masliza, Levelt, Eylem, Greiser, Andreas, Petrou, Mario, Krasopoulos, George, Forfar, John C., Kharbanda, Rajesh K., Channon, Keith M., Neubauer, Stefan, Piechnik, Stefan K., and Ferreira, Vanessa M.
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- 2017
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18. Inherited aortopathy assessment in bicuspid aortic valve disease relative
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Bissell, Malenka M, Biasiolli, Luca, Oswal, Abhishek, Loudon, Margaret, Watkins, Hugh, Neubauer, Stefan, and Myerson, Saul G
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- 2016
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19. Automated quality control in image segmentation: application to the UK Biobank cardiac MR imaging study
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Robinson, Robert, Valindria, Vanya V., Bai, Wenjia, Oktay, Ozan, Kainz, Bernhard, Suzuki, Hideaki, Sanghvi, Mihir M., Aung, Nay, Paiva, Jos$é$ Miguel, Zemrak, Filip, Fung, Kenneth, Lukaschuk, Elena, Lee, Aaron M., Carapella, Valentina, Kim, Young Jin, Piechnik, Stefan K., Neubauer, Stefan, Petersen, Steffen E., Page, Chris, Matthews, Paul M., Rueckert, Daniel, Glocker, Ben, Engineering & Physical Science Research Council (EPSRC), GlaxoSmithKline, National Institute for Health Research, UK DRI Ltd, Commission of the European Communities, and Innovate UK
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FOS: Computer and information sciences ,Population imaging ,Nuclear Medicine & Medical Imaging ,Segmentation ,Computer Vision and Pattern Recognition (cs.CV) ,Computer Science - Computer Vision and Pattern Recognition ,Automatic quality control ,1102 Cardiovascular Medicine And Haematology ,cs.CV - Abstract
Background: The trend towards large-scale studies including population imaging poses new challenges in terms of quality control (QC). This is a particular issue when automatic processing tools, e.g. image segmentation methods, are employed to derive quantitative measures or biomarkers for later analyses. Manual inspection and visual QC of each segmentation isn't feasible at large scale. However, it's important to be able to automatically detect when a segmentation method fails so as to avoid inclusion of wrong measurements into subsequent analyses which could lead to incorrect conclusions. Methods: To overcome this challenge, we explore an approach for predicting segmentation quality based on Reverse Classification Accuracy, which enables us to discriminate between successful and failed segmentations on a per-cases basis. We validate this approach on a new, large-scale manually-annotated set of 4,800 cardiac magnetic resonance scans. We then apply our method to a large cohort of 7,250 cardiac MRI on which we have performed manual QC. Results: We report results used for predicting segmentation quality metrics including Dice Similarity Coefficient (DSC) and surface-distance measures. As initial validation, we present data for 400 scans demonstrating 99% accuracy for classifying low and high quality segmentations using predicted DSC scores. As further validation we show high correlation between real and predicted scores and 95% classification accuracy on 4,800 scans for which manual segmentations were available. We mimic real-world application of the method on 7,250 cardiac MRI where we show good agreement between predicted quality metrics and manual visual QC scores. Conclusions: We show that RCA has the potential for accurate and fully automatic segmentation QC on a per-case basis in the context of large-scale population imaging as in the UK Biobank Imaging Study., Comment: 14 pages, 7 figures, Journal of Cardiovascular Magnetic Resonance
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- 2019
20. Systems-level organization of yeast methylotrophic lifestyle.
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Rußmayer, Hannes, Buchetics, Markus, Gruber, Clemens, Valli, Minoska, Grillitsch, Karlheinz, Modarres, Gerda, Guerrasio, Raffaele, Klavins, Kristaps, Neubauer, Stefan, Drexler, Hedda, Steiger, Matthias, Troyer, Christina, Chalabi, Ali Al, Krebiehl, Guido, Sonntag, Denise, Zellnig, Günther, Daum, Günther, Graf, Alexandra B., Altmann, Friedrich, and Koellensperger, Gunda
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YEAST ,PICHIA pastoris ,ALCOHOL oxidase ,DIHYDROXYACETONE ,PEROXISOMES ,CALVIN cycle - Abstract
Background: Some yeasts have evolved a methylotrophic lifestyle enabling them to utilize the single carbon compound methanol as a carbon and energy source. Among them, Pichia pastoris (syn. Komagataella sp.) is frequently used for the production of heterologous proteins and also serves as a model organism for organelle research. Our current knowledge of methylotrophic lifestyle mainly derives from sophisticated biochemical studies which identified many key methanol utilization enzymes such as alcohol oxidase and dihydroxyacetone synthase and their localization to the peroxisomes. C1 assimilation is supposed to involve the pentose phosphate pathway, but details of these reactions are not known to date. Results: In this work we analyzed the regulation patterns of 5,354 genes, 575 proteins, 141 metabolites, and fluxes through 39 reactions of P. pastoris comparing growth on glucose and on a methanol/glycerol mixed medium, respectively. Contrary to previous assumptions, we found that the entire methanol assimilation pathway is localized to peroxisomes rather than employing part of the cytosolic pentose phosphate pathway for xylulose-5-phosphate regeneration. For this purpose, P. pastoris (and presumably also other methylotrophic yeasts) have evolved a duplicated methanol inducible enzyme set targeted to peroxisomes. This compartmentalized cyclic C1 assimilation process termed xylose-monophosphate cycle resembles the principle of the Calvin cycle and uses sedoheptulose- 1,7-bisphosphate as intermediate. The strong induction of alcohol oxidase, dihydroxyacetone synthase, formaldehyde and formate dehydrogenase, and catalase leads to high demand of their cofactors riboflavin, thiamine, nicotinamide, and heme, respectively, which is reflected in strong up-regulation of the respective synthesis pathways on methanol. Methanol-grown cells have a higher protein but lower free amino acid content, which can be attributed to the high drain towards methanol metabolic enzymes and their cofactors. In context with up-regulation of many amino acid biosynthesis genes or proteins, this visualizes an increased flux towards amino acid and protein synthesis which is reflected also in increased levels of transcripts and/or proteins related to ribosome biogenesis and translation. Conclusions: Taken together, our work illustrates how concerted interpretation of multiple levels of systems biology data can contribute to elucidation of yet unknown cellular pathways and revolutionize our understanding of cellular biology. [ABSTRACT FROM AUTHOR]
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- 2015
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21. The global cardiovascular magnetic resonance registry (GCMR) of the society for cardiovascular magnetic resonance (SCMR): its goals, rationale, data infrastructure, and current developments
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Kwong, Raymond Y., Petersen, Steffen E., Schulz-Menger, Jeanette, Arai, Andrew E., Bingham, Scott E., Chen, Yucheng, Choi, Yuna L., Cury, Ricardo C., Ferreira, Vanessa M., Flamm, Scott D., Steel, Kevin, Bandettini, W. Patricia, Martin, Edward T., Nallamshetty, Leelakrishna, Neubauer, Stefan, Raman, Subha V., Schelbert, Erik B., Valeti, Uma S., Cao, Jie Jane, Reichek, Nathaniel, Young, Alistair A., Fexon, Lyuba, Pivovarov, Misha, Ferrari, Victor A., and Simonetti, Orlando P.
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Registry ,Cardiovascular magnetic resonance ,Imaging ,Patient management ,Therapeutic implications - Abstract
Background: With multifaceted imaging capabilities, cardiovascular magnetic resonance (CMR) is playing a progressively increasing role in the management of various cardiac conditions. A global registry that harmonizes data from international centers, with participation policies that aim to be open and inclusive of all CMR programs, can support future evidence-based growth in CMR. Methods: The Global CMR Registry (GCMR) was established in 2013 under the auspices of the Society for Cardiovascular Magnetic Resonance (SCMR). The GCMR team has developed a web-based data infrastructure, data use policy and participation agreement, data-harmonizing methods, and site-training tools based on results from an international survey of CMR programs. Results: At present, 17 CMR programs have established a legal agreement to participate in GCMR, amongst them 10 have contributed CMR data, totaling 62,456 studies. There is currently a predominance of CMR centers with more than 10 years of experience (65%), and the majority are located in the United States (63%). The most common clinical indications for CMR have included assessment of cardiomyopathy (21%), myocardial viability (16%), stress CMR perfusion for chest pain syndromes (16%), and evaluation of etiology of arrhythmias or planning of electrophysiological studies (15%) with assessment of cardiomyopathy representing the most rapidly growing indication in the past decade. Most CMR studies involved the use of gadolinium-based contrast media (95%). Conclusions: We present the goals, mission and vision, infrastructure, preliminary results, and challenges of the GCMR. Trial registration Identification number on ClinicalTrials.gov: NCT02806193. Registered 17 June 2016. Electronic supplementary material The online version of this article (doi:10.1186/s12968-016-0321-7) contains supplementary material, which is available to authorized users.
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- 2017
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22. Changes in creatine transporter function duringcardiac maturation in the rat.
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Fischer, Alexandra, Hove, Michiel ten, Sebag-Montefiore, Liam, Wagner, Helga, Clarke, Kieran, Watkins, Hugh, Lygate, Craig A., and Neubauer, Stefan
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MYOCARDIUM ,CREATINE kinase ,PHOSPHOCREATINE ,HEART metabolism ,ISOENZYMES - Abstract
Background: It is well established that the immature myocardium preferentially utilises non-oxidative energygenerating pathways. It exhibits low energy-transfer capacity via the creatine kinase (CK) shuttle, reflected in phosphocreatine (PCr), total creatine and CK levels that are much lower than those of adult myocardium. The mechanisms leading to gradually increasing energy transfer capacity during maturation are poorly understood. Creatine is not synthesised in the heart, but taken up exclusively by the action of the creatine transporter protein (CrT). To determine whether this transporter is ontogenically regulated, the present study serially examined CrT gene expression pattern, together with creatine uptake kinetics and resulting myocardial creatine levels, in rats over the first 80 days of age. Results: Rats were studied during the late prenatal period (-2 days before birth) and 7, 13, 21, 33, 50 and 80 days after birth. Activity of cardiac citrate synthase, creatine kinase and its isoenzymes as well as lactate dehydrogenase (LDH) and its isoenzymes demonstrated the well-described shift from anaerobic towards aerobic metabolism. mRNA levels of CrT in the foetal rat hearts, as determined by real-time PCR, were about 30% of the mRNA levels in the adult rat heart and gradually increased during development. Creatine uptake in isolated perfused rat hearts increased significantly from 3.0 nmol/min/gww at 13 days old to 4.9 nmol/min/gww in 80 day old rats. Accordingly, total creatine content in hearts, measured by HPLC, increased steadily during maturation (30 nmol/mg protein (-2 days) vs 87 nmol/mg protein (80 days)), and correlated closely with CrT gene expression. Conclusions: The maturation-dependant alterations of CK and LDH isoenzyme activities and of mitochondrial oxidative capacity were paralleled by a progressive increase of CrT expression, creatine uptake kinetics and creatine content in the heart. [ABSTRACT FROM AUTHOR]
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- 2010
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23. Identification of cardiac malformations in mice lacking Ptdsr using a novel high-throughput magnetic resonance imaging technique.
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Schneider, Jürgen E., Böse, Jens, Bamforth, Simon D., Gruber, Achim D., Broadbent, Carol, Clarke, Kieran, Neubauer, Stefan, Lengeling, Andreas, and Bhattacharya, Shoumo
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HEART abnormalities ,MICE ,PHOSPHATIDYLSERINES ,MAGNETIC resonance imaging ,VENTRICULAR septal defects - Abstract
Background: Congenital heart defects are the leading non-infectious cause of death in children. Genetic studies in the mouse have been crucial to uncover new genes and signaling pathways associated with heart development and congenital heart disease. The identification of murine models of congenital cardiac malformations in high-throughput mutagenesis screens and in gene-targeted models is hindered by the opacity of the mouse embryo. Results: We developed and optimized a novel method for high-throughput multi-embryo magnetic resonance imaging (MRI). Using this approach we identified cardiac malformations in phosphatidylserine receptor (Ptdsr) deficient embryos. These included ventricular septal defects, double-outlet right ventricle, and hypoplasia of the pulmonary artery and thymus. These results indicate that Ptdsr plays a key role in cardiac development. Conclusions: Our novel multi-embryo MRI technique enables high-throughput identification of murine models for human congenital cardiopulmonary malformations at high spatial resolution. The technique can be easily adapted for mouse mutagenesis screens and, thus provides an important new tool for identifying new mouse models for human congenital heart diseases. [ABSTRACT FROM AUTHOR]
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- 2004
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24. Simplifying cardiovascular magnetic resonance pulse sequence terminology
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Friedrich, Matthias G, Bucciarelli-Ducci, Chiara, White, James A, Plein, Sven, Moon, James C, Almeida, Ana G, Kramer, Christopher M, Neubauer, Stefan, Pennell, Dudley J, Petersen, Steffen E, Kwong, Raymond Y, Ferrari, Victor A, Schulz-Menger, Jeanette, Sakuma, Hajime, Schelbert, Erik B, Larose, Éric, Eitel, Ingo, Carbone, Iacopo, Taylor, Andrew J, Young, Alistair, de Roos, Albert, and Nagel, Eike
- Abstract
We propose a set of simplified terms to describe applied Cardiovascular Magnetic Resonance (CMR) pulse sequence techniques in clinical reports, scientific articles and societal guidelines or recommendations. Rather than using various technical details in clinical reports, the description of the technical approach should be based on the purpose of the pulse sequence. In scientific papers or other technical work, this should be followed by a more detailed description of the pulse sequence and settings. The use of a unified set of widely understood terms would facilitate the communication between referring physicians and CMR readers by increasing the clarity of CMR reports and thus improve overall patient care. Applied in research articles, its use would facilitate non-expert readers’ understanding of the methodology used and its clinical meaning.
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- 2014
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25. Synergistic effect on cardiac energetics by targeting the creatine kinase system: in vivo application of high-resolution 31P-CMRS in the mouse.
- Author
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Maguire, Mahon L., McAndrew, Debra J., Lake, Hannah A., Ostrowski, Philip J., Zervou, Sevasti, Neubauer, Stefan, Lygate, Craig A., and Schneider, Jurgen E.
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ADENOSINE triphosphate metabolism , *MYOCARDIUM , *IN vivo studies , *ANIMAL experimentation , *CREATINE kinase , *NUCLEAR magnetic resonance spectroscopy , *CREATINE , *PHOSPHOCREATINE , *RESEARCH funding , *DESCRIPTIVE statistics , *MICE - Abstract
Background: Phosphorus cardiovascular magnetic resonance spectroscopy (31P-CMRS) has emerged as an important tool for the preclinical assessment of myocardial energetics in vivo. However, the high rate and diminutive size of the mouse heart is a challenge, resulting in low resolution and poor signal-to-noise. Here we describe a refined high-resolution 31P-CMRS technique and apply it to a novel double transgenic mouse (dTg) with elevated myocardial creatine and creatine kinase (CK) activity. We hypothesised a synergistic effect to augment energetic status, evidenced by an increase in the ratio of phosphocreatine-to-adenosine-triphosphate (PCr/ATP). Methods and results: Single transgenic Creatine Transporter overexpressing (CrT-OE, n = 7) and dTg mice (CrT-OE and CK, n = 6) mice were anaesthetised with isoflurane to acquire 31P-CMRS measurements of the left ventricle (LV) utilising a two-dimensional (2D), threefold under-sampled density-weighted chemical shift imaging (2D-CSI) sequence, which provided high-resolution data with nominal voxel size of 8.5 µl within 70 min. (1H-) cine-CMR data for cardiac function assessment were obtained in the same imaging session. Under a separate examination, mice received invasive haemodynamic assessment, after which tissue was collected for biochemical analysis. Myocardial creatine levels were elevated in all mouse hearts, but only dTg exhibited significantly elevated CK activity, resulting in a 51% higher PCr/ATP ratio in heart (3.01 ± 0.96 vs. 2.04 ± 0.57—mean ± SD; dTg vs. CrT-OE), that was absent from adjacent skeletal muscle. No significant differences were observed for any parameters of LV structure and function, confirming that augmentation of CK activity does not have unforeseen consequences for the heart. Conclusions: We have developed an improved 31P-CMRS methodology for the in vivo assessment of energetics in the murine heart which enabled high-resolution imaging within acceptable scan times. Mice over-expressing both creatine and CK in the heart exhibited a synergistic elevation in PCr/ATP that can now be tested for therapeutic potential in models of chronic heart failure. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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26. Cardiovascular magnetic resonance reference values of mitral and tricuspid annular dimensions: the UK Biobank cohort.
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Ricci, Fabrizio, Aung, Nay, Gallina, Sabina, Zemrak, Filip, Fung, Kenneth, Bisaccia, Giandomenico, Paiva, Jose Miguel, Khanji, Mohammed Y., Mantini, Cesare, Palermi, Stefano, Lee, Aaron M., Piechnik, Stefan K., Neubauer, Stefan, and Petersen, Stefen E.
- Abstract
Background: Mitral valve (MV) and tricuspid valve (TV) apparatus geometry are essential to define mechanisms and etiologies of regurgitation and to inform surgical or transcatheter interventions. Given the increasing use of cardiovascular magnetic resonance (CMR) for the evaluation of valvular heart disease, we aimed to establish CMR-derived age- and sex-specific reference values for mitral annular (MA) and tricuspid annular (TA) dimensions and tethering indices derived from truly healthy Caucasian adults.Methods: 5065 consecutive UK Biobank participants underwent CMR using cine balanced steady-state free precession imaging at 1.5 T. Participants with non-Caucasian ethnicity, prevalent cardiovascular disease and other conditions known to affect cardiac chamber size and function were excluded. Absolute and indexed reference ranges for MA and TA diameters and tethering indices were stratified by gender and age (45–54, 55–64, 65–74 years).Results: Overall, 721 (14.2%) truly healthy participants aged 45–74 years (54% women) formed the reference cohort. Absolute MA and TA diameters, MV tenting length and MV tenting area, were significantly larger in men. Mean ± standard deviation (SD) end-diastolic and end-systolic MA diameters in the 3-chamber view (anteroposterior diameter) were 2.9 ± 0.4 cm (1.5 ± 0.2 cm/m2) and 3.3 ± 0.4 cm (1.7 ± 0.2 cm/m2) in men, and 2.6 ± 0.4 cm (1.6 ± 0.2 cm/m2) and 3.0 ± 0.4 cm (1.8 ± 0.2 cm/m2) in women, respectively. Mean ± SD end-diastolic and end-systolic TA diameters in the 4-chamber view were 3.2 ± 0.5 cm (1.6 ± 0.3 cm/m2) and 3.2 ± 0.5 cm (1.7 ± 0.3 cm/m2) in men, and 2.9 ± 0.4 cm (1.7 ± 0.2 cm/m2) and 2.8 ± 0.4 cm (1.7 ± 0.3 cm/m2) in women, respectively. With advancing age, end-diastolic TA diameter became larger and posterior MV leaflet angle smaller in both sexes. Reproducibility of measurements was good to excellent with an inter-rater intraclass correlation coefficient (ICC) between 0.92 and 0.98 and an intra-rater ICC between 0.90 and 0.97.Conclusions: We described age- and sex-specific reference ranges of MA and TA dimensions and tethering indices in the largest validated healthy Caucasian population. Reference ranges presented in this study may help to improve the distinction between normal and pathological states, prompting the identification of subjects that may benefit from advanced cardiac imaging for annular sizing and planning of valvular interventions. [ABSTRACT FROM AUTHOR]
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- 2020
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27. Measuring inorganic phosphate and intracellular pH in the healthy and hypertrophic cardiomyopathy hearts by in vivo 7T 31P-cardiovascular magnetic resonance spectroscopy.
- Author
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Valkovič, Ladislav, Clarke, William T., Schmid, Albrecht I., Raman, Betty, Ellis, Jane, Watkins, Hugh, Robson, Matthew D., Neubauer, Stefan, and Rodgers, Christopher T.
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- 2019
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28. Adenosine stress CMR T1-mapping detects early microvascular dysfunction in patients with type 2 diabetes mellitus without obstructive coronary artery disease.
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Levelt, Eylem, Piechnik, Stefan K., Liu, Alexander, Wijesurendra, Rohan S., Mahmod, Masliza, Ariga, Rina, Francis, Jane M., Greiser, Andreas, Clarke, Kieran, Neubauer, Stefan, Ferreira, Vanessa M., and Karamitsos, Theodoros D.
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ADENOSINES , *TYPE 2 diabetes , *PAPER chromatography , *PEPTIDES , *RESEARCH funding , *DATA analysis software , *DESCRIPTIVE statistics - Abstract
Background: Type 2 diabetes mellitus (T2DM) is associated with coronary microvascular dysfunction in the absence of obstructive coronary artery disease (CAD). Cardiovascular magnetic resonance (CMR) T1-mapping at rest and during adenosine stress can assess coronary vascular reactivity. We hypothesised that the non-contrast T1 response to vasodilator stress will be altered in patients with T2DM without CAD compared to controls due to coronary microvascular dysfunction. Methods: Thirty-one patients with T2DM and sixteen matched healthy controls underwent CMR (3 T) for cine, rest and adenosine stress non-contrast T1-mapping (ShMOLLI), first-pass perfusion and late gadolinium enhancement (LGE) imaging. Significant CAD (>50% coronary luminal stenosis) was excluded in all patients by coronary computed tomographic angiography. Results: All subjects had normal left ventricular (LV) ejection and LV mass index, with no LGE. Myocardial perfusion reserve index (MPRI) was lower in T2DM than in controls (1.60 ± 0.44 vs 2.01 ± 0.42; p = 0.008). There was no difference in rest native T1 values (p = 0.59). During adenosine stress, T1 values increased significantly in both T2DM patients (from 1196 ± 32 ms to 1244 ± 44 ms, p < 0.001) and controls (from 1194 ± 26 ms to 1273 ± 44 ms, p < 0. 001). T2DM patients showed blunted relative stress non-contrast T1 response (T2DM: ΔT1 = 4.1 ± 2.9% vs. controls: ΔT1 = 6.6 ± 2.6%, p = 0.007) due to a blunted maximal T1 during adenosine stress (T2DM 1244 ± 44 ms vs. controls 1273 ± 44 ms, p = 0.045). Conclusions: Patients with well controlled T2DM, even in the absence of arterial hypertension and significant CAD, exhibit blunted maximal non-contrast T1 response during adenosine vasodilatory stress, likely reflecting coronary microvascular dysfunction. Adenosine stress and rest T1 mapping can detect subclinical abnormalities of the coronary microvasculature, without the need for gadolinium contrast agents. CMR may identify early features of the diabetic heart phenotype and subclinical cardiac risk markers in patients with T2DM, providing an opportunity for early therapeutic intervention. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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29. Measurement of myocardial native T1 in cardiovascular diseases and norm in 1291 subjects.
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Liu, Joanna M., Liu, Alexander, Leal, Joana, McMillan, Fiona, Francis, Jane, Greiser, Andreas, Rider, Oliver J., Myerson, Saul, Neubauer, Stefan, Ferreira, Vanessa M., and Piechnik, Stefan K.
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CARDIOMYOPATHIES , *CARDIAC hypertrophy , *MYOCARDIUM , *BODY surface mapping , *CARDIOVASCULAR diseases , *REPORTING of diseases , *REFERENCE values , *CONTRAST media , *DATA analysis software , *DESCRIPTIVE statistics , *ANATOMY , *DIAGNOSIS - Abstract
Background: Native T1-mapping provides quantitative myocardial tissue characterization for cardiovascular diseases (CVD), without the need for gadolinium. However, its translation into clinical practice is hindered by differences between techniques and the lack of established reference values. We provide typical myocardial T1-ranges for 18 commonly encountered CVDs using a single T1-mapping technique - Shortened Look-Locker Inversion Recovery (ShMOLLI), also used in the large UK Biobank and Hypertrophic Cardiomyopathy Registry study. Methods: We analyzed 1291 subjects who underwent CMR (1.5-Tesla, MAGNETOM-Avanto, Siemens Healthcare, Erlangen, Germany) between 2009 and 2016, who had a single CVD diagnosis, with mid-ventricular T1-map assessment. A region of interest (ROI) was placed on native T1-maps in the "most-affected myocardium", characterized by the presence of late gadolinium enhancement (LGE), or regional wall motion abnormalities (RWMA) on cines. Another ROI was placed in the "reference myocardium" as far as possible from LGE/RWMA, and in the septum if no focal abnormality was present. To further define normality, we included native T1 of healthy subjects from an existing dataset after sub-endocardial pixelerosions. Results: Native T1 of patients with normal CMR (938 ± 21 ms) was similar compared to healthy subjects (941 ± 23 ms). Across all patient groups (57 ± 19 yrs., 65% males), focally affected myocardium had significantly different T1 value compared to reference myocardium (all p < 0.001). In the affected myocardium, cardiac amyloidosis (1119 ± 61 ms) had the highest native T1 compared to normal and all other CVDs, while iron-overload (795 ± 58 ms) and Anderson-Fabry disease (863 ± 23 ms) had the lowest native reference T1 (all p < 0.001). Future studies designed to detect the large T1 differences between affected and reference myocardium are estimated to require small sample-sizes (n < 50). However, studies designed to detect the small T1 differences between reference myocardium in CVDs and healthy controls can require several thousand of subjects. Conclusions: We provide typical T1-ranges for common clinical cardiac conditions in the largest cohort to-date, using ShMOLLI T1-mapping at 1.5 T. Sample-size calculations from this study may be useful for the design of future studies and trials that use T1-mapping as an endpoint. [ABSTRACT FROM AUTHOR]
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- 2017
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30. Reference ranges for cardiac structure and function using cardiovascular magnetic resonance (CMR) in Caucasians from the UK Biobank population cohort.
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Petersen, Steffen E., Nay Aung, Sanghvi, Mihir M., Zemrak, Filip, Fung, Kenneth, Miguel Paiva, Jose, Francis, Jane M., Khanji, Mohammed Y., Lukaschuk, Elena, Lee, Aaron M., Carapella, Valentina, Young Jin Kim, Leeson, Paul, Piechnik, Stefan K., and Neubauer, Stefan
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HEART atrium , *HEART ventricles , *AGE distribution , *STATISTICAL correlation , *LEFT heart ventricle , *HEART physiology , *RIGHT heart ventricle , *MAGNETIC resonance imaging , *REFERENCE values , *RESEARCH funding , *SEX distribution , *T-test (Statistics) , *WHITE people , *DATA analysis software , *STROKE volume (Cardiac output) , *INTRACLASS correlation , *PHYSIOLOGY , *ANATOMY - Abstract
Background: Cardiovascular magnetic resonance (CMR) is the gold standard method for the assessment of cardiac structure and function. Reference ranges permit differentiation between normal and pathological states. To date, this study is the largest to provide CMR specific reference ranges for left ventricular, right ventricular, left atrial and right atrial structure and function derived from truly healthy Caucasian adults aged 45-74. Methods: Five thousand sixty-five UK Biobank participants underwent CMR using steady-state free precession imaging at 1.5 Tesla. Manual analysis was performed for all four cardiac chambers. Participants with non-Caucasian ethnicity, known cardiovascular disease and other conditions known to affect cardiac chamber size and function were excluded. Remaining participants formed the healthy reference cohort; reference ranges were calculated and were stratified by gender and age (45-54, 55-64, 65-74). Results: After applying exclusion criteria, 804 (16.²%) participants were available for analysis. Left ventricular (LV) volumes were larger in males compared to females for absolute and indexed values. With advancing age, LV volumes were mostly smaller in both sexes. LV ejection fraction was significantly greater in females compared to males (mean ± standard deviation [SD] of 61 ± 5% vs 58 ± 5%) and remained static with age for both genders. In older age groups, LV mass was lower in men, but remained virtually unchanged in women. LV mass was significantly higher in males compared to females (mean ± SD of 53 ± 9 g/m² vs 4² ± 7 g/m²). Right ventricular (RV) volumes were significantly larger in males compared to females for absolute and indexed values and were smaller with advancing age. RV ejection fraction was higher with increasing age in females only. Left atrial (LA) maximal volume and stroke volume were significantly larger in males compared to females for absolute values but not for indexed values. LA ejection fraction was similar for both sexes. Right atrial (RA) maximal volume was significantly larger in males for both absolute and indexed values, while RA ejection fraction was significantly higher in females. Conclusions: We describe age- and sex-specific reference ranges for the left ventricle, right ventricle and atria in the largest validated normal Caucasian population. [ABSTRACT FROM AUTHOR]
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- 2017
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31. Cardiac 31 P MRS analysis development: Improved fitting of 2, 3 DPG.
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Dass, Sairia, Tyler, Damian, Neubauer, Stefan, Clarke, Kieran, and Cochlin, Lowri E.
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ACYCLIC acids , *ADENOSINE triphosphatase , *CONFERENCES & conventions , *NUCLEAR magnetic resonance spectroscopy , *PHOSPHOCREATINE , *THERAPEUTICS - Abstract
An abstract on cardiac 31 P molar receptivity spectral (MRS) analysis of human heart is presented.
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- 2013
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32. 3D cardiac navigation with rapid multi shot EPI.
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Hess, Aaron T., van der Kouwe, André J., Neubauer, Stefan, and Robson, Matthew D.
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SPECTRUM analysis - Abstract
An abstract of the conference paper "3D cardiac navigation with rapid multi shot EPI," by Aaron T. Hess and colleagues is presented.
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- 2012
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33. Highly accelerated cardiac functional MRI in rodent hearts using compressed sensing and parallel imaging at 9.4T.
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Wech, Tobias, Lygate, Craig A., Neubauer, Stefan, Köstler, Herbert, and Schneider, Jurgen E.
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MAGNETIC resonance imaging , *HEART - Abstract
An abstract of the conference paper "Highly accelerated cardiac functional MRI in rodent hearts using compressed sensing and parallel imaging at 9.4T," by Tobias Wech, and colleagues is presented.
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- 2012
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34. Histological validation of ShMOLLI equilibrium contrast CMR for the measurement of diffuse myocardial fibrosis.
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White, Steven K., Piechnik, Stefan K., Neubauer, Stefan, Robson, Matthew D., and Moon, James
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CARDIOVASCULAR system , *FIBROSIS , *MAGNETIC resonance imaging - Abstract
An abstract of the conference paper "Histological validation of ShMOLLI equilibrium contrast CMR for the measurement of diffuse myocardial fibrosis," by Steven K. White and colleagues is presented.
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- 2012
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35. UK Biobank's cardiovascular magnetic resonance protocol.
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Petersen, Steffen E., Matthews, Paul M., Francis, Jane M., Robson, Matthew D., Zemrak, Filip, Boubertakh, Redha, Young, Alistair A., Hudson, Sarah, Weale, Peter, Garratt, Steve, Collins, Rory, Piechnik, Stefan, and Neubauer, Stefan
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CARDIOVASCULAR disease diagnosis , *EXPERIMENTAL design , *LONGITUDINAL method , *MAGNETIC resonance imaging , *RESEARCH methodology , *DESCRIPTIVE statistics - Abstract
Background: UK Biobank's ambitious aim is to perform cardiovascular magnetic resonance (CMR) in 100,000 people previously recruited into this prospective cohort study of half a million 40-69 year-olds. Methods/design: We describe the CMR protocol applied in UK Biobank's pilot phase, which will be extended into the main phase with three centres using the same equipment and protocols. The CMR protocol includes white blood CMR (sagittal anatomy, coronary and transverse anatomy), cine CMR (long axis cines, short axis cines of the ventricles, coronal LVOT cine), strain CMR (tagging), flow CMR (aortic valve flow) and parametric CMR (native T1 map). Discussion: This report will serve as a reference to researchers intending to use the UK Biobank resource or to replicate the UK Biobank cardiovascular magnetic resonance protocol in different settings. [ABSTRACT FROM AUTHOR]
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- 2016
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36. Systolic ShMOLLI myocardial T1-mapping for improved robustness to partial-volume effects and applications in tachyarrhythmias.
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Ferreira, Vanessa M., Wijesurendra, Rohan S., Liu, Alexander, Greiser, Andreas, Casadei, Barbara, Robson, Matthew D., Neubauer, Stefan, and Piechnik, Stefan K.
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RESEARCH funding , *SEX distribution , *SINOATRIAL node , *TACHYCARDIA , *DATA analysis software , *DESCRIPTIVE statistics , *KRUSKAL-Wallis Test - Abstract
Background: T1-mapping using the Shortened Modified Look-Locker Inversion Recovery (ShMOLLI) technique enables non-invasive assessment of important myocardial tissue characteristics. However, tachyarrhythmia may cause mistriggering and inaccurate T1 estimation. We set out to test whether systolic T1-mapping might overcome this, and whether T1 values or data quality would be significantly different compared to conventional diastolic T1-mapping. Methods: Native T1 maps were acquired using ShMOLLI at 1.5 T (Magnetom Avanto, Siemens Healthcare) in 10 healthy volunteers (5 male) in sinus rhythm, at varying prescribed trigger delay (TD) times: 0, 50, 100 and 150 ms (all "systolic"), 340 ms (MOLLI TD 500 ms, the conventional TD for ShMOLLI) and also "end diastolic". T1 maps were also acquired using a shorter readout, to explore the effect of reducing image readout time and sensitivity to systolic motion. The feasibility and image quality of systolic T1-mapping was tested in 15 patients with tachyarrhythmia ( = 13 atrial fibrillation, = 2 sinus tachycardia; mean HR range 93-121 bpm). n n Results: In healthy volunteers, systolic readout increased the thickness of myocardium compared to the diastolic readout. There was a small overall effect of TD on T1 values ( = 0.04), with slightly shorter T1 values in systole p compared to diastole (maximum difference 10 ms). While there were apparent gender differences (with no effect of TD on T1 values in males, more marked differences in females, and exaggeration of this effect in thinner myocardial segments in females), dilatation and erosion of contours suggested that the effect of TD on T1 in females was almost entirely due to more partial-volume effects in diastole. All T1 maps were of excellent quality, but systolic TD and shorter readout were associated with less variability in segmental T1 values. In tachycardic patients, systolic acquisitions produced consistently excellent T1 maps (median R² = 0.993). Conclusions: In healthy volunteers, systolic ShMOLLI T1-mapping reduces T1 variability and reports clinically equivalent T1 values to conventional diastolic readout; slightly shorter T1 values in systole are mostly explained by reduced partial-volume effects due to the increase in functional myocardial thickness. In patients with tachyarrhythmia, systolic ShMOLLI T1-mapping is feasible, circumvents mistriggering and produces excellent quality T1 maps. This extends its clinical applicability to challenging rhythms (such as rapid atrial fibrillation) and aids the investigation of thinner myocardial segments. With further validation, systolic T1-mapping may become a new and convenient standard for myocardial T1-mapping. [ABSTRACT FROM AUTHOR]
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- 2015
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37. 4D flow cardiovascular magnetic resonance consensus statement.
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Dyverfeldt, Petter, Bissell, Malenka, Barker, Alex J., Bolger, Ann F., Carlhäll, Carl-Johan, Ebbers, Tino, Francios, Christopher J., Frydrychowicz, Alex, Geiger, Julia, Giese, Daniel, Hope, Michael D., Kilner, Philip J., Kozerke, Sebastian, Myerson, Saul, Neubauer, Stefan, Wieben, Oliver, and Markl, Michael
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BLOOD flow measurement , *HEMODYNAMICS , *MAGNETIC resonance imaging , *QUALITY control , *MAGNETIC resonance angiography - Abstract
Pulsatile blood flow through the cavities of the heart and great vessels is time-varying and multidirectional. Access to all regions, phases and directions of cardiovascular flows has formerly been limited. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has enabled more comprehensive access to such flows, with typical spatial resolution of 1.5x1.5x1.5 - 3x3x3 mm³, typical temporal resolution of 30-40 ms, and acquisition times in the order of 5 to 25 min. This consensus paper is the work of physicists, physicians and biomedical engineers, active in the development and implementation of 4D Flow CMR, who have repeatedly met to share experience and ideas. The paper aims to assist understanding of acquisition and analysis methods, and their potential clinical applications with a focus on the heart and greater vessels. We describe that 4D Flow CMR can be clinically advantageous because placement of a single acquisition volume is straightforward and enables flow through any plane across it to be calculated retrospectively and with good accuracy. We also specify research and development goals that have yet to be satisfactorily achieved. Derived flow parameters, generally needing further development or validation for clinical use, include measurements of wall shear stress, pressure difference, turbulent kinetic energy, and intracardiac flow components. The dependence of measurement accuracy on acquisition parameters is considered, as are the uses of different visualization strategies for appropriate representation of time-varying multidirectional flow fields. Finally, we offer suggestions for more consistent, user-friendly implementation of 4D Flow CMR acquisition and data handling with a view to multicenter studies and more widespread adoption of the approach in routine clinical investigations. [ABSTRACT FROM AUTHOR]
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- 2015
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38. Gender specific patterns of age-related decline in aortic stiffness: a cardiovascular magnetic resonance study including normal ranges.
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Nethononda, Richard M., Lewandowski, Adam J., Stewart, Ross, Kylinterias, Ilias, Whitworth, Polly, Francis, Jane, Leeson, Paul, Watkins, Hugh, Neubauer, Stefan, and Rider, Oliver J.
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AORTA physiology , *DIAGNOSIS of diabetes , *AORTA , *ABDOMINAL aorta , *AGE distribution , *AGING , *ANALYSIS of variance , *ARTERIES , *BLOOD pressure , *CARDIOLOGY , *CHOLESTEROL , *DIAGNOSTIC imaging , *DOPPLER echocardiography , *HEART rate monitoring , *MAGNETIC resonance imaging , *SMOKING , *BODY mass index , *HUMAN research subjects , *CASE-control method , *PATIENT selection , *WAIST-hip ratio , *DATA analysis software , *PHYSIOLOGY , *ANATOMY ,DIAGNOSIS of aortic diseases - Abstract
Background: Young females exhibit lower cardiovascular event rates that young men, a pattern which is lost, or even reversed with advancing age. As aortic stiffness is a powerful risk factor for cardiovascular events, a gender difference with advancing age could provide a plausible explanation for this pattern. Methods: 777 subjects (♀n = 408, ♂n = 369) across a wide range of age (21-85 years) underwent cardiovascular magnetic resonance to assess aortic pulse wave velocity (PWV) and, in addition, aortic distensibility at three levels; 1) ascending aorta (Ao) and 2) proximal descending aorta (PDA) at the level of the pulmonary artery and 3) the abdominal aorta (DDA). Results: There was a strong negative correlation between increasing age and regional aortic distensibility (Ao♀R-0.84, ♂R-0.80, PDA♀R-0.82, ♂R-0.77, DDA♀R-0.80, ♂R-0.71 all p < 0.001) and a strong positive correlation with PWV, (♀R0.53, ♂R 0.63 both p < 0.001). Even after adjustment for mean arterial pressure, body mass index, heart rate, smoking and diabetes, females exhibited a steeper decrease in all distensibility measures in response to increasing age (Ao♀-1.3 vs ♂-1.1 mmHg-1, PDA ♀-1.2 vs ♂-1.0 mmHg, DDA ♀-1.8 vs ♂-1.4 mmHg-1 per 10 years increase in age all p < 0.001). No gender difference in PWV increase with age was observed (p = 0.11). Conclusion: Although advancing age is accompanied by increased aortic stiffness in both males and females, a significant sex difference in the rate of change exists, with females showing a steeper decline in aortic elasticity. As aortic stiffness is strongly related to cardiovascular events our observations may explain the increase in cardiovascular event rates that accompanies the menopausal age in women. [ABSTRACT FROM AUTHOR]
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- 2015
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39. Review of Journal of Cardiovascular Magnetic Resonance 2013.
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Pennell, Dudley John, Baksi, Arun John, Kilner, Philip John, Mohiaddin, Raad Hashem, Prasad, Sanjay Kumar, Alpendurada, Francisco, Babu-Narayan, Sonya Vidya, Neubauer, Stefan, and Firmin, David Nigel
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CARDIOVASCULAR disease diagnosis , *MAGNETIC resonance imaging , *MANUSCRIPTS , *SERIAL publications , *PERIODICAL articles , *IMPACT factor (Citation analysis) - Abstract
There were 109 articles published in the Journal of Cardiovascular Magnetic Resonance (JCMR) in 2013, which is a 21% increase on the 90 articles published in 2012. The quality of the submissions continues to increase. The editors are delighted to report that the 2012 JCMR Impact Factor (which is published in June 2013) has risen to 5.11, up from 4.44 for 2011 (as published in June 2012), a 15% increase and taking us through the 5 threshold for the first time. The 2012 impact factor means that the JCMR papers that were published in 2010 and 2011 were cited on average 5.11 times in 2012. The impact factor undergoes natural variation according to citation rates of papers in the 2 years following publication, and is significantly influenced by highly cited papers such as official reports. However, the progress of the journal's impact over the last 5 years has been impressive. Our acceptance rate is <25% and has been falling because the number of articles being submitted has been increasing. In accordance with Open-Access publishing, the JCMR articles go on-line as they are accepted with no collating of the articles into sections or special thematic issues. For this reason, the Editors have felt that it is useful once per calendar year to summarize the papers for the readership into broad areas of interest or theme, so that areas of interest can be reviewed in a single article in relation to each other and other recent JCMR articles. The papers are presented in broad themes and set in context with related literature and previously published JCMR papers to guide continuity of thought in the journal. We hope that you find the open-access system increases wider reading and citation of your papers, and that you will continue to send your quality manuscripts to JCMR for publication. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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40. Adenosine stress native T1 mapping in severe aortic stenosis: evidence for a role of the intravascular compartment on myocardial T1 values.
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Mahmod, Masliza, Piechnik, Stefan K., Levelt, Eylem, Ferreira, Vanessa M., Francis, Jane M., Lewis, Andrew, Pal, Nikhil, Dass, Sairia, Ashrafian, Houman, Neubauer, Stefan, and Karamitsos, Theodoros D.
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LEFT heart ventricle , *HEART physiology , *MYOCARDIUM physiology , *ADENOSINES , *AORTIC stenosis , *VASODILATION , *DIAGNOSTIC imaging , *HEART function tests , *PROSTHETIC heart valves , *HYPEREMIA , *MAGNETIC resonance imaging , *POSTOPERATIVE period , *CONTRAST media , *SEVERITY of illness index , *INTRAVASCULAR space , *PREOPERATIVE period , *DIAGNOSIS - Abstract
Background: Myocardial T1 relaxation times have been reported to be markedly abnormal in diverse myocardial pathologies, ascribed to interstitial changes, evaluated by T1 mapping and calculation of extracellular volume (ECV). T1 mapping is sensitive to myocardial water content of both intra- and extracellular in origin, but the effect of intravascular compartment changes on T1 has been largely neglected. We aimed to assess the role of intravascular compartment on native (pre-contrast) T1 values by studying the effect of adenosine-induced vasodilatation in patients with severe aortic stenosis (AS) before and after aortic valve replacement (AVR). Methods: 42 subjects (26 patients with severe AS without obstructive coronary artery disease and 16 controls) underwent cardiovascular magnetic resonance at 3 T for native T1-mapping (ShMOLLI), first-pass perfusion (myocardial perfusion reserve index-MPRI) at rest and during adenosine stress, and late gadolinium enhancement (LGE). Results: AS patients had increased resting myocardial T1 (1196 ± 47 ms vs. 1168 ± 27 ms, p = 0.037), reduced MPRI (0.92 ± 0.31 vs. 1.74 ± 0.32, p < 0.001), and increased left ventricular mass index (LVMI) and LGE volume compared to controls. During adenosine stress, T1 in AS was similar to controls (1240 ± 51 ms vs. 1238 ± 54 ms, p = 0.88), possibly reflecting a similar level of maximal coronary vasodilatation in both groups. Conversely, the T1 response to stress was blunted in AS (AT1 3.7 ± 2.7% vs. 6.0 ± 4.2% in controls, p = 0.013). Seven months after AVR (n = 16) myocardial T1 and response to adenosine stress recovered towards normal. Native T1 values correlated with reduced MPRI, aortic valve area, and increased LVMI. Conclusions: Our study suggests that native myocardial T1 values are not only influenced by interstitial and intracellular water changes, but also by changes in the intravascular compartment. Performing T1 mapping during or soon after vasodilator stress may affect ECV measurements given that hyperemia alone appears to substantially alter T1 values. [ABSTRACT FROM AUTHOR]
- Published
- 2014
41. Native T1-mapping detects the location, extent and patterns of acute myocarditis without the need for gadolinium contrast agents.
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Ferreira, Vanessa M., Piechnik, Stefan K., Dall¿Armellina, Erica, Karamitsos, Theodoros D., Francis, Jane M., Ntusi, Ntobeko, Holloway, Cameron, Choudhury, Robin P., Kardos, Attila, Robson, Matthew D., Friedrich, Matthias G., and Neubauer, Stefan
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MAGNETIC resonance imaging , *ANALYSIS of variance , *LONGITUDINAL method , *CARDIOMYOPATHIES , *STATISTICS , *T-test (Statistics) , *U-statistics , *DATA analysis , *CONTRAST media , *RECEIVER operating characteristic curves , *DATA analysis software , *DESCRIPTIVE statistics , *DIAGNOSIS - Abstract
Background Acute myocarditis can be diagnosed on cardiovascular magnetic resonance (CMR) using multiple techniques, including late gadolinium enhancement (LGE) imaging, which requires contrast administration. Native T1-mapping is significantly more sensitive than LGE and conventional T2-weighted (T2W) imaging in detecting myocarditis. The aims of this study were to demonstrate how to display the non-ischemic patterns of injury and to quantify myocardial involvement in acute myocarditis without the need for contrast agents, using topographic T1-maps and incremental T1 thresholds. Methods We studied 60 patients with suspected acute myocarditis (median 3 days from presentation) and 50 controls using CMR (1.5 T), including:(1) dark-blood T2W imaging; (2) native T1-mapping (ShMOLLI); (3) LGE. Analysis included: (1) global myocardial T2 signal intensity (SI) ratio compared to skeletal muscle; (2) myocardial T1 times; (3) areas of injury by T2W, T1-mapping and LGE. Results Compared to controls, patients had more edema (global myocardial T2 SI ratio 1.71 ± 0.27 vs.1.56 ± 0.15), higher mean myocardial T1 (1011 ± 64 ms vs. 946 ± 23 ms) and more areas of injury as detected by T2W (median 5% vs. 0%), T1 (median 32% vs. 0.7%) and LGE (median 11% vs. 0%); all p < 0.001. A threshold of T1 > 990 ms (sensitivity 90%, specificity 88%) detected significantly larger areas of involvement than T2W and LGE imaging in patients, and additional areas of injury when T2W and LGE were negative. T1-mapping significantly improved the diagnostic confidence in an additional 30% of cases when at least one of the conventional methods (T2W, LGE) failed to identify any areas of abnormality. Using incremental thresholds, T1-mapping can display the non-ischemic patterns of injury typical of myocarditis. Conclusion Native T1-mapping can display the typical non-ischemic patterns in acute myocarditis, similar to LGE imaging but without the need for contrast agents. In addition, T1-mapping offers significant incremental diagnostic value, detecting additional areas of myocardial involvement beyond T2W and LGE imaging and identified extra cases when these conventional methods failed to identify abnormalities. In the future, it may be possible to perform gadolinium-free CMR using cine and T1-mapping for tissue characterization and may be particularly useful for patients in whom gadolinium contrast is contraindicated. [ABSTRACT FROM AUTHOR]
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- 2014
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42. Intercentre reproducibility of cardiac apparent diffusion coefficient and fractional anisotropy in healthy volunteers.
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Tunnicliffe, Elizabeth M., Scott, Andrew D., Ferreira, Pedro, Ariga, Rina, McGill, Laura-Ann, Nielles-Vallespin, Sonia, Neubauer, Stefan, Pennell, Dudley J., Robson, Matthew D., and Firmin, David N.
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MYOCARDIUM physiology , *MAGNETIC resonance imaging , *MEDICAL cooperation , *IMAGING phantoms , *RESEARCH , *RESEARCH funding , *T-test (Statistics) , *DESCRIPTIVE statistics ,RESEARCH evaluation - Abstract
Background Diffusion tensor cardiac magnetic resonance (DT-CMR) enables probing of the microarchitecture of the myocardium, but the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) reported in healthy volunteers have been inconsistent. The aim of this study was to validate a stimulated-echo diffusion sequence using phantoms, and to assess the intercentre reproducibility of in-vivo diffusion measures using the sequence. Methods and results A stimulated-echo, cardiac-gated DT-CMR sequence with a reduced-field-of-view, single- shot EPI readout was used at two centres with 3 T MRI scanners. Four alkane phantoms with known diffusivities were scanned at a single centre using a stimulated echo sequence and a spin-echo Stejskal-Tanner diffusion sequence. The median (maximum, minimum) difference between the DT-CMR sequence and Stejskal-Tanner sequence was 0.01 (0.04, 0.0006)x10-3 mm²/s (2%), and between the DT-CMR sequence and literature diffusivities was 0.02 (0.05, 0.006)x10-3 mm²/s (4%). The same ten healthy volunteers were scanned using the DT-CMR sequence at the two centres less than seven days apart. Average ADC and FA were calculated in a single mid- ventricular, short axis slice. Intercentre differences were tested for statistical significance at the p < 0.05 level using paired t-tests. The mean ADC ± standard deviation for all subjects averaged over both centres was 1.10 ± 0.06x10-3 mm²/s in systole and 1.20 ± 0.09x10-3 mm²/s in diastole; FA was 0.41 ± 0.04 in systole and 0.54 ± 0.03 in diastole. With similarly- drawn regions-of-interest, systolic ADC (difference 0.05x10-3 mm²/s), systolic FA (difference 0.003) and diastolic FA (difference 0.01) were not statistically significantly different between centres (p > 0.05), and only the diastolic ADC showed a statistically significant, but numerically small, difference of 0.07x10-3 mm²/s (p = 0.047). The intercentre, intrasubject coefficients of variance were: systolic ADC 7%, FA 6%; diastolic ADC 7%, FA 3%. Conclusions This is the first study to demonstrate the accuracy of a stimulated-echo DT-CMR sequence in phantoms, and demonstrates the feasibility of obtaining reproducible ADC and FA in healthy volunteers at separate centres with well-matched sequences and processing. [ABSTRACT FROM AUTHOR]
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- 2014
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43. Myocardial perfusion and oxygenation are impaired during stress in severe aortic stenosis and correlate with impaired energetics and subclinical left ventricular dysfunction.
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Mahmod, Masliza, Francis, Jane M., Pal, Nikhil, Lewis, Andrew, Dass, Sairia, De Silva, Ravi, Petrou, Mario, Sayeed, Rana, Westaby, Stephen, Robson, Matthew D., Ashrafian, Houman, Neubauer, Stefan, and Karamitsos, Theodoros D.
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MAGNETIC resonance imaging , *HEART ventricle diseases , *ACTIVE oxygen in the body , *ADENOSINES , *AORTIC stenosis , *CHI-squared test , *STATISTICAL correlation , *FISHER exact test , *LEFT heart ventricle , *PERFUSION , *RESEARCH funding , *STATISTICS , *PHYSIOLOGICAL stress , *T-test (Statistics) , *U-statistics , *DATA analysis , *DATA analysis software , *DESCRIPTIVE statistics - Abstract
Background Left ventricular (LV) hypertrophy in aortic stenosis (AS) is characterized by reduced myocardial perfusion reserve due to coronary microvascular dysfunction. However, whether this hypoperfusion leads to tissue deoxygenation is unknown. We aimed to assess myocardial oxygenation in severe AS without obstructive coronary artery disease, and to investigate its association with myocardial energetics and function. Methods Twenty-eight patients with isolated severe AS and 15 controls underwent cardiovascular magnetic resonance (CMR) for assessment of perfusion (myocardial perfusion reserve index-MPRI) and oxygenation (blood-oxygen level dependent-BOLD signal intensity-SI change) during adenosine stress. LV circumferential strain and phosphocreatine/ adenosine triphosphate (PCr/ATP) ratios were assessed using tagging CMR and 31P MR spectroscopy, respectively. Results AS patients had reduced MPRI (1.1 ± 0.3 vs. controls 1.7 ± 0.3, p < 0.001) and BOLD SI change during stress (5.1 ± 8.9% vs. controls 18.2 ± 10.1%, p = 0.001), as well as reduced PCr/ATP (1.45 ± 0.21 vs. 2.00 ± 0.25, p < 0.001) and LV strain (-16.4 ± 2.7% vs. controls -21.3 ± 1.9%, p < 0.001). Both perfusion reserve and oxygenation showed positive correlations with energetics and LV strain. Furthermore, impaired energetics correlated with reduced strain. Eight months post aortic valve replacement (AVR) (n = 14), perfusion (MPRI 1.6 ± 0.5), oxygenation (BOLD SI change 15.6 ± 7.0%), energetics (PCr/ATP 1.86 ± 0.48) and circumferential strain (-19.4 ± 2.5%) improved significantly. Conclusions Severe AS is characterized by impaired perfusion reserve and oxygenation which are related to the degree of derangement in energetics and associated LV dysfunction. These changes are reversible on relief of pressure overload and hypertrophy regression. Strategies aimed at improving oxygen demand--supply balance to preserve myocardial energetics and LV function are promising future therapies. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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44. Subclinical myocardial inflammation and diffuse fibrosis are common in systemic sclerosis - a clinical study using myocardial T1-mapping and extracellular volume quantification.
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Ntusi, Ntobeko A. B., Piechnik, Stefan K., Francis, Jane M., Ferreira, Vanessa M., Rai, Aitzaz B. S., Matthews, Paul M., Robson, Matthew D., Moon, James, Wordsworth, Paul B., Neubauer, Stefan, and Karamitsos, Theodoros D.
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INFLAMMATION , *FIBROSIS , *MAGNETIC resonance imaging , *ECHOCARDIOGRAPHY , *CHI-squared test , *STATISTICAL correlation , *FISHER exact test , *LONGITUDINAL method , *MYOCARDIUM , *RESEARCH funding , *STATISTICS , *SYSTEMIC scleroderma , *T-test (Statistics) , *U-statistics , *DATA analysis , *DATA analysis software , *DESCRIPTIVE statistics , *DISEASE complications , *DIAGNOSIS - Abstract
Background Systemic sclerosis (SSc) is characterised by multi-organ tissue fibrosis including the myocardium. Diffuse myocardial fibrosis can be detected non-invasively by T1 and extracellular volume (ECV) quantification, while focal myocardial inflammation and fibrosis may be detected by T2-weighted and late gadolinium enhancement (LGE), respectively, using cardiovascular magnetic resonance (CMR). We hypothesised that multiparametric CMR can detect subclinical myocardial involvement in patients with SSc. Methods 19 SSc patients (18 female, mean age 55 ± 10 years) and 20 controls (19 female, mean age 56 ± 8 years) without overt cardiovascular disease underwent CMR at 1.5T, including cine, tagging, T1-mapping, T2-weighted, LGE imaging and ECV quantification. Results Focal fibrosis on LGE was found in 10 SSc patients (53%) but none of controls. SSc patients also had areas of myocardial oedema on T2-weighted imaging (median 13 vs. 0% in controls). SSc patients had significantly higher native myocardial T1 values (1007 ± 29 vs. 958 ± 20 ms, p < 0.001), larger areas of myocardial involvement by native T1 >990 ms (median 52 vs. 3% in controls) and expansion of ECV (35.4 ± 4.8 vs. 27.6 ± 2.5%, p < 0.001), likely representing a combination of low-grade inflammation and diffuse myocardial fibrosis. Regardless of any regional fibrosis, native T1 and ECV were significantly elevated in SSc and correlated with disease activity and severity. Although biventricular size and global function were preserved, there was impairment in the peak systolic circumferential strain (-16.8 ± 1.6 vs. -18.6 ± 1.0, p < 0.001) and peak diastolic strain rate (83 ± 26 vs. 114 ± 16 s-1, p < 0.001) in SSc, which inversely correlated with diffuse myocardial fibrosis indices. Conclusions Cardiac involvement is common in SSc even in the absence of cardiac symptoms, and includes chronic myocardial inflammation as well as focal and diffuse myocardial fibrosis. Myocardial abnormalities detected on CMR were associated with impaired strain parameters, as well as disease activity and severity in SSc patients. CMR may be useful in future in the study of treatments aimed at preventing or reducing adverse myocardial processes in SSc. [ABSTRACT FROM AUTHOR]
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- 2014
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45. Observational study of regional aortic size referenced to body size: production of a cardiovascular magnetic resonance nomogram.
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Davis, Anne E., Lewandowski, Adam J., Holloway, Cameron J., Ntusi, Ntobeko AB, Banerjee, Rajarshi, Nethononda, Richard, Pitcher, Alex, Francis, Jane M., Myerson, Saul G., Leeson, Paul, Donovan, Tim, Neubauer, Stefan, and Rider, Oliver J.
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AORTA , *AGE distribution , *ANALYSIS of variance , *ANTHROPOMETRY , *BODY size , *CARDIOVASCULAR diseases risk factors , *MAGNETIC resonance imaging , *SCIENTIFIC observation , *REGRESSION analysis , *SEX distribution , *STATISTICS , *DATA analysis , *INTER-observer reliability , *CROSS-sectional method , *DATA analysis software , *DESCRIPTIVE statistics , *ANATOMY ,RESEARCH evaluation - Abstract
Background Cardiovascular magnetic resonance (CMR) is regarded as the gold standard for clinical assessment of the aorta, but normal dimensions are usually referenced to echocardiographic and computed tomography data and no large CMR normal reference range exists. As a result we aimed to 1) produce a normal CMR reference range of aortic diameters and 2) investigate the relationship between regional aortic size and body surface area (BSA) in a large group of healthy subjects with no vascular risk factors. Methods 447 subjects (208 male, aged 19-70 years) without identifiable cardiac risk factors (BMI range 15.7-52.6 kg/m²) underwent CMR at 1.5 T to determine aortic diameter at three levels: the ascending aorta (Ao) and proximal descending aorta (PDA) at the level of the pulmonary artery, and the abdominal aorta (DDA), at a level 12 cm distal to the PDA. In addition, 201 of these subjects had aortic root imaging, allowing for measurements at the level of the aortic valve annulus (AV), aortic sinuses and sinotubular junction (STJ). Results Normal diameters (mean ±2 SD) were; AV annulus male(♂) 24.4 ± 5.4, female (♀) 21.0 ± 3.6 mm, aortic sinus♂32.4 ± 7.7, ♀27.6 ± 5.8 mm, ST-junction ♂25.0 ± 7.4, ♀21.8 ± 5.4 mm, Ao ♂26.7 ± 7.7, ♀25.5 ± 7.4 mm, PDA ♂20.6 ± 5.6, +18.9 ± 4.0 mm, DDA ♂17.6 ± 5.1, ♀16.4 ± 4.0 mm. Aortic root and thoracic aortic diameters increased at all levels measured with BSA. No gender difference was seen in the degree of dilatation with increasing BSA (p > 0.5 for all analyses). Conclusion Across both genders, increasing body size is characterized by a modest degree of aortic dilatation, even in the absence of traditional cardiovascular risk factors. [ABSTRACT FROM AUTHOR]
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- 2014
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46. Non-invasive imaging of carotid arterial restenosis using 3T cardiovascular magnetic resonance.
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Lindsay, Alistair C., Biasiolli, Luca, Knight, Steven, Cunnington, Colin, Robson, Matthew D., Neubauer, Stefan, Kennedy, James, Handa, Ashok, and Choudhury, Robin P.
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DISEASE relapse , *MAGNETIC resonance imaging , *CHI-squared test , *FISHER exact test , *STATISTICS , *T-test (Statistics) , *U-statistics , *DESCRIPTIVE statistics , *CAROTID endarterectomy , *DIAGNOSIS ,CAROTID artery stenosis - Abstract
Background Restenosis of the carotid artery is common following carotid endarterectomy, but analysis of lesion composition has mostly been based on histological study of explanted restenotic lesions. This study investigated the ability of 3T cardiovascular magnetic resonance (CMR) to determine the components of recurrent carotid artery disease and examined whether these differed from primary atherosclerotic plaque. Methods 50 patients underwent 3T CMR of both carotid arteries using a standard multicontrast protocol: time-of-flight (TOF), T1-weighted (T1W), T2-weighted (T2W), and PD-weighted (PDW) Turbo-Spin-Echo (TSE) sequences. 25 patients had previously undergone carotid endarterectomy (mean time since surgery 1580 days, range 45-6560 days), and 25 with primary asymptomatic atherosclerotic plaques served as controls. Two experienced reviewers analysed the multicontrast CMR images according to the presence or absence of major plaque features and assigned an overall classification type. Results In patients with recurrent carotid disease following endarterectomy, the mean degree of restenosis was 51% (range 30-90%). Three distinct types of restenosis were identified: 5 patients (20%) showed CMR characteristics of fibro-atheromatous tissue, 11 patients (44%) had plaque features consistent with possible myointimal (fibromuscular) hyperplasia, and 6 patients (24%) had recurrent plaque suggestive of further lipid accumulation. Three patients (12%) showed evidence of post-surgical dissection of the carotid intima. Compared to primary atherosclerotic plaques, restenotic plaques were more likely to contain fibro-atheromatous tissue (p = 0.05) and smooth muscle (p < 0.01), and less likely to contain lipid (p < 0.01). Composition did not differ significantly between patients with early and late restenosis. Conclusions As defined by CMR, restenotic lesions of the carotid artery fall into three distinct types and differ in composition from primary atherosclerotic plaques. If validated by subsequent histological studies, these findings could suggest a role for CMR in detecting high-risk (i.e. lipid-rich) restenotic lesions. [ABSTRACT FROM AUTHOR]
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- 2014
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47. Myocardial T1 mapping and extracellular volume quantification: a Society for Cardiovascular Magnetic Resonance (SCMR) and CMR Working Group of the European Society of Cardiology consensus statement.
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Moon, James C., Messroghli, Daniel R., Kellman, Peter, Piechnik, Stefan K., Robson, Matthew D., Ugander, Martin, Gatehouse, Peter D., Arai, Andrew E., Friedrich, Matthias G., Neubauer, Stefan, Schulz-Menger, Jeanette, and Schelbert, Erik B.
- Abstract
Rapid innovations in cardiovascular magnetic resonance (CMR) now permit the routine acquisition of quantitative measures of myocardial and blood T1 which are key tissue characteristics. These capabilities introduce a new frontier in cardiology, enabling the practitioner/investigator to quantify biologically important myocardial properties that otherwise can be difficult to ascertain clinically. CMR may be able to track biologically important changes in the myocardium by: a) native T1 that reflects myocardial disease involving the myocyte and interstitium without use of gadolinium based contrast agents (GBCA), or b) the extracellular volume fraction (ECV)-a direct GBCA-based measurement of the size of the extracellular space, reflecting interstitial disease. The latter technique attempts to dichotomize the myocardium into its cellular and interstitial components with estimates expressed as volume fractions. This document provides recommendations for clinical and research T1 and ECV measurement, based on published evidence when available and expert consensus when not. We address site preparation, scan type, scan planning and acquisition, quality control, visualisation and analysis, technical development. We also address controversies in the field. While ECV and native T1 mapping appear destined to affect clinical decision making, they lack multi-centre application and face significant challenges, which demand a community-wide approach among stakeholders. At present, ECV and native T1 mapping appear sufficiently robust for many diseases; yet more research is required before a large-scale application for clinical decision-making can be recommended. [ABSTRACT FROM AUTHOR]
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- 2013
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48. Imaging in population science: cardiovascular magnetic resonance in 100,000 participants of UK Biobank - rationale, challenges and approaches.
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Petersen, Steffen E., Matthews, Paul M., Bamberg, Fabian, Bluemke, David A., Francis, Jane M., Friedrich, Matthias G., Leeson, Paul, Nagel, Eike, Plein, Sven, Rademakers, Frank E., Young, Alistair A., Garratt, Steve, Peakman, Tim, Sellors, Jonathan, Collins, Rory, and Neubauer, Stefan
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RESEARCH methodology , *MEDICAL care costs , *QUALITY control , *PHENOTYPES , *MAGNETIC resonance angiography - Abstract
UK Biobank is a prospective cohort study with 500,000 participants aged 40 to 69. Recently an enhanced imaging study received funding. Cardiovascular magnetic resonance (CMR) will be part of a multi-organ, multi-modality imaging visit in 3-4 dedicated UK Biobank imaging centres that will acquire and store imaging data from 100,000 participants (subject to successful piloting). In each of UK Biobank's dedicated bespoke imaging centres, it is proposed that 15-20 participants will undergo a 2 to 3 hour visit per day, seven days a week over a period of 5-6 years. The imaging modalities will include brain MRI at 3 Tesla, CMR and abdominal MRI at 1.5 Tesla, carotid ultrasound and DEXA scans using carefully selected protocols. We reviewed the rationale, challenges and proposed approaches for concise phenotyping using CMR on such a large scale. Here, we discuss the benefits of this imaging study and review existing and planned population based cardiovascular imaging in prospective cohort studies. We will evaluate the CMR protocol, feasibility, process optimisation and costs. Procedures for incidental findings, quality control and data processing and analysis are also presented. As is the case for all other data in the UK Biobank resource, this database of images and related information will be made available through UK Biobank's Access Procedures to researchers (irrespective of their country of origin and whether they are academic or commercial) for health-related research that is in the public interest. [ABSTRACT FROM AUTHOR]
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- 2013
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49. Global and regional left ventricular myocardial deformation measures by magnetic resonance feature tracking in healthy volunteers: comparison with tagging and relevance of gender.
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Augustine, Daniel, Lewandowski, Adam J., Lazdam, Merzaka, Rai, Aitzaz, Francis, Jane, Myerson, Saul, Noble, Alison, Becher, Harald, Neubauer, Stefan, Petersen, Steffen E., and Leeson, Paul
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MAGNETIC resonance imaging evaluation , *ANALYSIS of variance , *MYOCARDIUM , *PROBABILITY theory , *RESEARCH funding , *STATISTICS , *T-test (Statistics) , *DATA analysis , *INTER-observer reliability , *REPEATED measures design , *DATA analysis software , *DESCRIPTIVE statistics ,RESEARCH evaluation - Abstract
Background: Feature Tracking software offers measurements of myocardial strain, velocities and displacement from cine cardiovascular magnetic resonance (CMR) images. We used it to record deformation parameters in healthy adults and compared values to those obtained by tagging. Methods: We used TomTec 2D Cardiac Performance Analysis software to derive global, regional and segmental myocardial deformation parameters in 145 healthy volunteers who had steady state free precession (SSFP) cine left ventricular short (basal, mid and apical levels) and long axis views (horizontal long axis, vertical long axis and left ventricular out flow tract) obtained on a 1.5 T Siemens Sonata scanner. 20 subjects also had tagged acquisitions and we compared global and regional deformation values obtained from these with those from Feature Tracking. Results: For globally averaged measurements of strain, only those measured circumferentially in short axis slices showed reasonably good levels of agreement between FT and tagging (limits of agreement ?0.06 to 0.04). Longitudinal strain showed wide limits of agreement (-0.16 to 0.03) with evidence of overestimation of strain by FT relative to tagging as the mean of both measures increased. Radial strain was systematically overestimated by FT relative to tagging with very wide limits of agreement extending to as much as 100% of the mean value (-0.01 to 0.23). Reproducibility showed similar relative trends with acceptable global inter-observer variability for circumferential measures (coefficient of variation 4.9%) but poor reproducibility in the radial direction (coefficient of variation 32.3%). Ranges for deformation parameters varied between basal, mid and apical LV levels with higher levels at base compared to apex, and between genders by both FT and tagging. Conclusions: FT measurements of circumferential but not longitudinally or radially directed global strain showed reasonable agreement with tagging and acceptable inter-observer reproducibility. We record provisional ranges of FT deformation parameters at global, regional and segmental levels. They show evidence of variation with gender and myocardial region in the volunteers studied, but have yet to be compared with tagging measurements at the segmental level. [ABSTRACT FROM AUTHOR]
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- 2013
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50. Normal variation of magnetic resonance T1 relaxation times in the human population at 1.5 T using ShMOLLI.
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Piechnik, Stefan K., Vanessa M Ferreira, Vanessa M., Lewandowski, Adam J., Ntusi, Ntobeko A. B., Banerjee, Rajarshi, Holloway, Cameron, Hofman, Mark B. M., Sado, Daniel M., Maestrini, Viviana, White, Steven K., Lazdam, Merzaka, Karamitsos, Theodoros, Moon, James C., Neubauer, Stefan, Leeson, Paul, and Robson, Matthew D.
- Abstract
Background: Quantitative T1-mapping is rapidly becoming a clinical tool in cardiovascular magnetic resonance (CMR) to objectively distinguish normal from diseased myocardium. The usefulness of any quantitative technique to identify disease lies in its ability to detect significant differences from an established range of normal values. We aimed to assess the variability of myocardial T1 relaxation times in the normal human population estimated with recently proposed Shortened Modified Look-Locker Inversion recovery (ShMOLLI) T1 mapping technique. Methods: A large cohort of healthy volunteers (n = 342, 50% females, age 11-69 years) from 3 clinical centres across two countries underwent CMR at 1.5T. Each examination provided a single average myocardial ShMOLLI T1 estimate using manually drawn myocardial contours on typically 3 short axis slices (average 3.4 ± 1.4), taking care not to include any blood pool in the myocardial contours. We established the normal reference range of myocardial and blood T1 values, and assessed the effect of potential confounding factors, including artefacts, partial volume, repeated measurements, age, gender, body size, hematocrit and heart rate. Results: Native myocardial ShMOLLI T1 was 962 ± 25 ms. We identify the partial volume as primary source of potential error in the analysis of respective T1 maps and use 1 pixel erosion to represent "midwall myocardial" T1, resulting in a 0.9% decrease to 953 ± 23 ms. Midwall myocardial ShMOLLI T1 was reproducible with an intraindividual, intra- and inter-scanner variability of ≤2%. The principle biological parameter influencing myocardial ShMOLLI T1 was the female gender, with female T1 longer by 24 ms up to the age of 45 years, after which there was no significant difference from males. After correction for age and gender dependencies, heart rate was the only other physiologic factor with a small effect on myocardial ShMOLLI T1 (6ms/10bpm). Left and right ventricular blood ShMOLLI T1 correlated strongly with each other and also with myocardial T1 with the slope of 0.1 that is justifiable by the resting partition of blood volume in myocardial tissue. Overall, the effect of all variables on myocardial ShMOLLI T1 was within 2% of relative changes from the average. Conclusion: Native T1-mapping using ShMOLLI generates reproducible and consistent results in normal individuals within 2% of relative changes from the average, well below the effects of most acute forms of myocardial disease. The main potential confounder is the partial volume effect arising from over-inclusion of neighbouring tissue at the manual stages of image analysis. In the study of cardiac conditions such as diffuse fibrosis or small focal changes, the use of "myocardial midwall" T1, age and gender matching, and compensation for heart rate differences may all help to improve the method sensitivity in detecting subtle changes. As the accuracy of current T1 measurement methods remains to be established, this study does not claim to report an accurate measure of T1, but that ShMOLLI is a stable and reproducible method for T1-mapping. [ABSTRACT FROM AUTHOR]
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- 2013
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