217 results on '"P Marcus"'
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2. Modifications of Passive Films
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P. Marcus
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- 2023
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3. Modifications of Passive Films formed on Ni–Cr–Fe Alloys with Chromium Content in the Alloy and Effects of Adsorbed or Segregated Sulphur
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D. Costa and P. Marcus
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- 2023
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4. Modification of Ta/Ta2O5 Films by Platinum Deposits
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O. Kerrec, D. Devilliers, C. Hinnen, P. Marcus, H. Cachet, and H. Froment
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- 2023
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5. When Brazil Got the Blues: The Diffusion of Blues in Brazil
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Alan P. Marcus
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Materials Science (miscellaneous) ,Business and International Management ,General Agricultural and Biological Sciences ,General Business, Management and Accounting ,Industrial and Manufacturing Engineering - Abstract
Thisarticlewillexamine theintroduction of blues in Brazil (1985-1992), a phenomenon thathas not yet been addressed in scholarly spheres until now. By highlighting the processes of globalization and the Brazilian blues band from Riode Janeiro, Blues Etílicos, I ask what were the spaces, places, and venues that helped to disseminate blues throughout Brazil? How does an African-American-based genre adopted and popularized by upper-and-middle-class white urbanites in Brazil? To answer these questions, I discuss the process ofglobalization and the Geography of music, political, musical,and cultural backdrops, and the end of Brazil’s military dictatorship in 1985, which overlappedwith a major Brazilian rock festival, “Rock in Rio,” and later, Brazil’s first blues festival in Ribeirão Preto in 1989. This article adds to the scholarly literature of music geography by looking at ongoing discussions of Brazil’s changing political, cultural, and musical landscapes.
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- 2022
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6. Using 'Autogeography,' sense of place and place-based approaches in the pedagogy of geographic thought
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Alan P. Marcus
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Software_GENERAL ,ComputingMilieux_THECOMPUTINGPROFESSION ,Interpretation (philosophy) ,Geography, Planning and Development ,Pedagogy ,ComputingMilieux_PERSONALCOMPUTING ,ComputingMilieux_COMPUTERSANDEDUCATION ,Sense of place ,Education - Abstract
This essay will discuss an approach in the pedagogy of geography that engages students with the interpretation, imagination, and the complex understandings and dimensions of geographic thought. My ...
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- 2021
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7. Dynamic computed tomographic assessment of the mitral annulus in patients with and without mitral prolapse
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Ian T. Mark, Roy P. Marcus, Rickey E. Carter, Thomas A. Foley, Asim Rizvi, Eric E. Williamson, Yugene Guo, Emily N. Sheedy, Nikkole M. Weber, and Shuai Leng
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Adult ,Male ,Computed Tomography Angiography ,Mitral prolapse ,Cardiac-Gated Imaging Techniques ,030204 cardiovascular system & hematology ,Coronary Angiography ,030218 nuclear medicine & medical imaging ,Electrocardiography ,03 medical and health sciences ,0302 clinical medicine ,Predictive Value of Tests ,Mitral valve ,Humans ,Medicine ,Mitral valve prolapse ,Radiology, Nuclear Medicine and imaging ,In patient ,cardiovascular diseases ,Mitral annulus ,Aged ,Retrospective Studies ,Computed tomography angiography ,Observer Variation ,Mitral Valve Prolapse ,Cardiac cycle ,medicine.diagnostic_test ,business.industry ,Reproducibility of Results ,Middle Aged ,medicine.disease ,Circumference ,medicine.anatomical_structure ,cardiovascular system ,Mitral Valve ,Female ,Cardiology and Cardiovascular Medicine ,business ,Nuclear medicine - Abstract
To obtain 3D CT measurements of mitral annulus throughout cardiac cycle using prototype mitral modeling software, assess interobserver agreement, and compare among patients with mitral prolapse (MP) and control group.Pre-procedural imaging is critical for planning of transcatheter mitral valve (MV) replacement. However, there is limited data regarding reliable CT-based measurements to accurately characterize the dynamic geometry of the mitral annulus in patients with MV disease.Patients with MP and control subjects without any MV disease who underwent ECG-gated cardiac CT were retrospectively identified. Multiphasic CT data was loaded into a prototype mitral modeling software. Multiple anatomical parameters in 3D space were recorded throughout the cardiac cycle (0-95%): annular circumference, planar-surface-area (PSA), anterior-posterior (A-P) distance, and anterolateral-posteromedial (AL-PM) distance. Comparisons were made among the two groups, with p 0.05 considered statistically significant. Interobserver agreement was assessed on ten patients using intraclass correlation coefficient (ICC) among 4 experienced readers.A total of 100 subjects were included: 50 with MP and 50 control. Annular dimensions were significantly higher in the MP group than control group, with circumference (144 ± 11 vs. 117±8 mm), PSA (1533 ± 247 vs. 1005 ± 142 mmA significant variation in the mitral annular measures between different cardiac phases and two groups was observed with excellent interobserver agreement.
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- 2020
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8. THE DANGERS OF THE GEOGRAPHICAL IMAGINATION IN THE U.S. EUGENICS MOVEMENT
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Alan P. Marcus
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media_common.quotation_subject ,05 social sciences ,Geography, Planning and Development ,0211 other engineering and technologies ,0507 social and economic geography ,021107 urban & regional planning ,Environmental ethics ,Nazism ,02 engineering and technology ,Racism ,Xenophobia ,Eugenics ,Relevance (law) ,050703 geography ,Earth-Surface Processes ,media_common - Abstract
This article offers a new synthesis of the role of geography and geographical thinking in the inception and diffusion of the U.S. eugenics movement and its relevance in social and racial sentiments...
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- 2020
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9. Skiffle in the U.K.: the indigenization of a musical genre
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Alan P. Marcus
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Cultural Studies ,Indigenization ,05 social sciences ,Geography, Planning and Development ,0211 other engineering and technologies ,0507 social and economic geography ,Cultural environment ,021107 urban & regional planning ,02 engineering and technology ,Musical ,Visual arts ,Popular music ,Sociology ,050703 geography - Abstract
This article examines the creation and diffusion of skiffle, and analyses how it emerged from the transatlantic flow of popular music from the United States to the United Kingdom, and the process b...
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- 2020
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10. Improved prediction of postoperative pediatric cerebellar mutism syndrome using an artificial neural network
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Jai Sidpra, Adam P Marcus, Ulrike Löbel, Sebastian M Toescu, Derek Yecies, Gerald Grant, Kristen Yeom, David M Mirsky, Hani J Marcus, Kristian Aquilina, and Kshitij Mankad
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Background Postoperative pediatric cerebellar mutism syndrome (pCMS) is a common but severe complication that may arise following the resection of posterior fossa tumors in children. Two previous studies have aimed to preoperatively predict pCMS, with varying results. In this work, we examine the generalization of these models and determine if pCMS can be predicted more accurately using an artificial neural network (ANN). Methods An overview of reviews was performed to identify risk factors for pCMS, and a retrospective dataset was collected as per these defined risk factors from children undergoing resection of primary posterior fossa tumors. The ANN was trained on this dataset and its performance was evaluated in comparison to logistic regression and other predictive indices via analysis of receiver operator characteristic curves. The area under the curve (AUC) and accuracy were calculated and compared using a Wilcoxon signed-rank test, with P Results Two hundred and four children were included, of whom 80 developed pCMS. The performance of the ANN (AUC 0.949; accuracy 90.9%) exceeded that of logistic regression (P Conclusion Using an ANN, we show improved prediction of pCMS in comparison to previous models and conventional methods.
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- 2022
11. Synergistic effect of ionic liquid (IL) cation and anion inhibits negative difference effect on Mg in water - IL mixtures
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D. Kurchavov, U. Rustambek, A. Ottochian, G. Lefèvre, A. Seyeux, I. Ciofini, P. Marcus, V. Lair, and P. Volovitch
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General Chemical Engineering ,General Materials Science ,General Chemistry - Published
- 2022
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12. IMG-02. Improved prediction of postoperative paediatric cerebellar mutism syndrome using an artificial neural network
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Jai Sidpra, Adam P Marcus, Ulrike Löbel, Sebastian Toescu, Derek Yecies, Gerald Grant, Kristen Yeom, David M Mirsky, Hani J Marcus, Kristian Aquilina, and Kshitij Mankad
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Cancer Research ,Oncology ,Neurology (clinical) - Abstract
BACKGROUND: Postoperative paediatric cerebellar mutism syndrome (pCMS) is a common but severe complication which may arise following the resection of posterior fossa tumours in children. Two previous studies have aimed to preoperatively predict pCMS, with varying results. In this work, we examine the generalisation of these models and determine if pCMS can be predicted more accurately using an artificial neural network (ANN). METHODS: An overview of reviews was performed to identify risk factors for pCMS, and a retrospective dataset collected as per these defined risk factors from children undergoing resection of primary posterior fossa tumours. The ANN was trained on this dataset and its performance evaluated in comparison to logistic regression and other predictive indices via analysis of receiver operator characteristic curves. Area under the curve (AUC) and accuracy were calculated and compared using a Wilcoxon signed rank test, with p
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- 2022
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13. Computed tomography angiography versus Agatston score for diagnosis of coronary artery disease in patients with stable chest pain: individual patient data meta-analysis of the international COME-CCT Consortium
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Viktoria, Wieske, Mario, Walther, Benjamin, Dubourg, Hatem, Alkadhi, Bjarne L, Nørgaard, Matthijs F L, Meijs, Axel C P, Diederichsen, Yung-Liang, Wan, Hans, Mickley, Konstantin, Nikolaou, Abbas A, Shabestari, Bjørn A, Halvorsen, Eugenio, Martuscelli, Kai, Sun, Bernhard A, Herzog, Roy P, Marcus, Sebastian, Leschka, Mario J, Garcia, Kristian A, Ovrehus, Juhani, Knuuti, Vladymir, Mendoza-Rodriguez, Nuno, Bettencourt, Simone, Muraglia, Ronny R, Buechel, Philipp A, Kaufmann, Elke, Zimmermann, Jean-Claude, Tardif, Matthew J, Budoff, Peter, Schlattmann, and Marc, Dewey
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Chest Pain ,Computed Tomography Angiography ,Predictive Value of Tests ,Coronary Stenosis ,Humans ,Calcium ,Coronary Artery Disease ,Coronary Angiography ,Tomography, X-Ray Computed - Abstract
There is conflicting evidence about the comparative diagnostic accuracy of the Agatston score versus computed tomography angiography (CTA) in patients with suspected obstructive coronary artery disease (CAD).To determine whether CTA is superior to the Agatston score in the diagnosis of CAD.In total 2452 patients with stable chest pain and a clinical indication for invasive coronary angiography (ICA) for suspected CAD were included by the Collaborative Meta-analysis of Cardiac CT (COME-CCT) Consortium. An Agatston score of400 was considered positive, and obstructive CAD defined as at least 50% coronary diameter stenosis on ICA was used as the reference standard.Obstructive CAD was diagnosed in 44.9% of patients (1100/2452). The median Agatston score was 74. Diagnostic accuracy of CTA for the detection of obstructive CAD (81.1%, 95% confidence interval [CI]: 77.5 to 84.1%) was significantly higher than that of the Agatston score (68.8%, 95% CI: 64.2 to 73.1%, p0.001). Among patients with an Agatston score of zero, 17% (101/600) had obstructive CAD. Diagnostic accuracy of CTA was not significantly different in patients with low to intermediate (1 to100, 100-400) versus moderate to high Agatston scores (401-1000,1000).Results in our international cohort show CTA to have significantly higher diagnostic accuracy than the Agatston score in patients with stable chest pain, suspected CAD, and a clinical indication for ICA. Diagnostic performance of CTA is not affected by a higher Agatston score while an Agatston score of zero does not reliably exclude obstructive CAD.• CTA showed significantly higher diagnostic accuracy (81.1%, 95% confidence interval [CI]: 77.5 to 84.1%) for diagnosis of coronary artery disease when compared to the Agatston score (68.8%, 95% CI: 64.2 to 73.1%, p0.001). • Diagnostic performance of CTA was not affected by increased amount of calcium and was not significantly different in patients with low to intermediate (1 to100, 100-400) versus moderate to high Agatston scores (401-1000,1000). • Seventeen percent of patients with an Agatston score of zero showed obstructive coronary artery disease by invasive angiography showing absence of coronary artery calcium cannot reliably exclude coronary artery disease.
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- 2021
14. Editorial: Institutional Implications of the Covid-19 Pandemic for Geographers in/of Latin America
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Diana Tung, Eugenio Arima, John C. Finn, Jorn Seemann, Gabriela Valdivia, Alan P. Marcus, Martha G. Bell, and Jessica Budds
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2019-20 coronavirus outbreak ,Economic growth ,Latin Americans ,Geography ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Geography, Planning and Development ,Pandemic ,Earth-Surface Processes - Published
- 2021
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15. The evolving role of imaging for small bowel neuroendocrine neoplasms: estimated impact of imaging and disease-free survival in a retrospective observational study
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Joel G. Fletcher, Cynthia H. McCollough, Jeff L. Fidler, Michael L. Wells, Shannon P. Sheedy, Yong S Lee, John M. Barlow, Roy P. Marcus, Matthew P. Johnson, Rickey E. Carter, Ajit H. Goenka, Sarasa Kim, Stephanie L. Hansel, and David H. Bruining
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Disease free survival ,medicine.medical_specialty ,Abdominal pain ,Radiological and Ultrasound Technology ,medicine.diagnostic_test ,business.industry ,Urology ,Incidence (epidemiology) ,Abdominal ct ,Gastroenterology ,Retrospective cohort study ,Hepatology ,030218 nuclear medicine & medical imaging ,Endoscopy ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,Internal medicine ,medicine ,Radiology, Nuclear Medicine and imaging ,Abdominal Neoplasms ,Radiology ,medicine.symptom ,business - Abstract
To determine how small bowel neuroendocrine neoplasms (SBNEN’s) are diagnosed and examine the effect of CT enterography (CTE) on diagnosis and rates of disease-free survival. Histopathologically-confirmed SBNEN’s diagnosed at our institution between 1996 and 2016 were identified. Clinical presentation, radiology, endoscopy, surgery, and pathology reports were reviewed and compared between consecutive 5-year periods. Of the 178 SBNEN initially diagnosed at our institution, the incidence increased 12-fold from 9 (during 1996–2000) to 114 (during 2011–2016). Comparing the first 5 to the last 5 years, GI bleeding and abdominal pain increased significantly as indications (with both increasing from 0 to > 25%, p ≤ 0.023). Initial diagnosis by radiology increased 2-fold [from 33% (n = 3) to 66% (n = 75); p = 0.263]. Detection of a small bowel mass and the suggestion that SBNEN was present varied significantly between imaging modalities (p
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- 2020
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16. Where Is the Geography? The Geographical Predicaments of the Panethnic Terms Hispanic and Latino
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Alan P. Marcus
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Geography ,Latin Americans ,Geography, Planning and Development ,Hispanic latino ,Ethnology ,Racialization ,Earth-Surface Processes - Published
- 2020
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17. Extent of resection and survival for oligodendroglioma: a U.S. population-based study
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Christopher M. Adams, Jeffrey N. Bruce, Tony J. C. Wang, Peter Canoll, E. Sander Connolly, Logan P Marcus, Michael B. Sisti, Adam M. Sonabend, Andrew L.A. Garton, Connor J. Kinslow, Alfred I. Neugut, Guy M. McKhann, Simon K. Cheng, and Ali I Rae
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Adult ,Male ,Oncology ,Cancer Research ,medicine.medical_specialty ,Adolescent ,Oligodendroglioma ,Population ,Subgroup analysis ,Neurosurgical Procedures ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Epidemiology ,medicine ,Humans ,Child ,education ,Retrospective Studies ,education.field_of_study ,Brain Neoplasms ,business.industry ,Hazard ratio ,Infant, Newborn ,Infant ,Retrospective cohort study ,Middle Aged ,Prognosis ,medicine.disease ,Debulking ,United States ,Survival Rate ,Neurology ,Child, Preschool ,030220 oncology & carcinogenesis ,Cohort ,Female ,Neurology (clinical) ,business ,030217 neurology & neurosurgery ,Follow-Up Studies - Abstract
National guidelines recommend maximal safe resection of low-grade and high-grade oligodendrogliomas. However, there is no level 1 evidence to support these guidelines, and recent retrospective studies on the topic have yielded mixed results. To assess the association between extent of resection (EOR) and survival for oligodendrogliomas in the general U.S. population. Cases diagnosed between 2004 and 2013 were selected from the Surveillance, Epidemiology, and End-Results (SEER) Program and retrospectively analyzed for treatment, prognostic factors, and survival times. Cases that did not undergo tumor de-bulking surgery (e.g. no surgery or biopsy alone) were compared to subtotal resection (resection) and gross-total resection (GTR). The primary end-points were overall survival (OS) and cause-specific survival (CSS). An external validation cohort with 1p/19q-codeleted tumors was creating using the TCGA and GSE16011 datasets. 3135 Cases were included in the final analysis. The 75% survival time (75ST) and 5-year survival rates were 47 months and 70.8%, respectively. Subtotal resection (STR, 75ST = 50 months) and GTR (75ST = 61 months) were associated with improved survival times compared to cases that did not undergo surgical debulking (75ST = 20 months, P
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- 2019
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18. Confederate Exodus
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ALAN P. MARCUS
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- 2021
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19. Automated radiomic analysis of CT images to predict likelihood of spontaneous passage of symptomatic renal stones
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Kristin C. Mara, Joel G. Fletcher, Ashish Khandelwal, David J. Bartlett, Roy P. Marcus, Andrea Ferrero, Payam Mohammadinejad, Cynthia H. McCollough, Taylor R. Moen, Felicity Enders, and John C. Lieske
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Multivariate statistics ,Ureteral Calculi ,Article ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Hounsfield scale ,Medicine ,Analysis software ,Humans ,Radiology, Nuclear Medicine and imaging ,Renal colic ,Probability ,Observer Variation ,Univariate analysis ,Receiver operating characteristic ,business.industry ,030208 emergency & critical care medicine ,Middle Aged ,Coronal plane ,Emergency Medicine ,Female ,Tomography ,medicine.symptom ,Ureter ,business ,Nuclear medicine ,Tomography, X-Ray Computed - Abstract
PURPOSE: To evaluate the ability of a semi-automated radiomic analysis software in predicting the likelihood of spontaneous passage of urinary stones compared with manual measurements. METHODS: Symptomatic patients visiting the emergency department with suspected stones in either kidney or ureters who underwent a CT scan were included. Patients were followed for up to 6 months for the outcome of a trial of passage. Maximum stone diameters in axial and coronal images were measured manually. Stone length, width, height, max diameter, volume, the mean and standard deviation of the Hounsfield units, and morphologic features were also measured using automated radiomic analysis software. Multivariate models were developed using these data to predict subsequent spontaneous stone passage, with results expressed as the area under a receiver operating curve (AUC). RESULTS: One hundred eighty-four patients (69 females) with a median age of 56 years were included. Spontaneous stone passage occurred in 114 patients (62%). Univariate analysis demonstrated an AUC of 0.83 and 0.82 for the maximum stone diameter determined manually in the axial and coronal planes, respectively. Multivariate models demonstrated an AUC of 0.82 for a model including manual measurement of maximum stone diameter in axial and coronal planes. The same AUC was found for a model including automatic measurement of maximum height and diameter of the stone. Further addition of morphological parameters measured automatically did not increase AUC beyond 0.83. CONCLUSION: The semi-automated radiomic analysis of urinary stones shows similar accuracy compared with manual measurements for predicting urinary stone passage. Further studies are needed to predict clinical impacts of reporting the likelihood of urinary stone passage and improving inter-observer variation using automatic radiomic analysis software.
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- 2020
20. Editorial: Mobility, Connectivity, and the Implications of Covid-19 for Latin American Geography
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Gabriela Valdivia, Johnny Finn, Jorn Seemann, Alan P. Marcus, Eric D. Carter, Martha G. Bell, Jessica Budds, Diana Tung, and Eugenio Arima
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2019-20 coronavirus outbreak ,Geography ,Latin Americans ,Coronavirus disease 2019 (COVID-19) ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Geography, Planning and Development ,Ethnology ,Earth-Surface Processes - Published
- 2020
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21. Impact of neurosurgeon specialization on patient outcomes for intracranial and spinal surgery: a retrospective analysis of the Nationwide Inpatient Sample 1998–2009
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David C. Chang, Brian R. Hirshman, Tyler S Cole, Logan P. Marcus, Brandon A. McCutcheon, Bob S. Carter, Michael W. Heffner, Clark C. Chen, and Brandon C Gabel
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Male ,medicine.medical_specialty ,Percentile ,Multivariate analysis ,medicine.medical_treatment ,Neurosurgical Procedures ,03 medical and health sciences ,0302 clinical medicine ,Specialization (functional) ,medicine ,Retrospective analysis ,Humans ,Retrospective Studies ,Inpatients ,business.industry ,Mortality rate ,Brain ,General Medicine ,Middle Aged ,Surgery ,Neurosurgeons ,Treatment Outcome ,Spinal Cord ,030220 oncology & carcinogenesis ,Spinal fusion ,Cohort ,Female ,Neurosurgery ,business ,030217 neurology & neurosurgery ,Specialization - Abstract
OBJECTIVEThe subspecialization of neurosurgical practice is an ongoing trend in modern neurosurgery. However, it remains unclear whether the degree of surgeon specialization is associated with improved patient outcomes. The authors hypothesized that a trend toward increased neurosurgeon specialization was associated with improved patient morbidity and mortality rates.METHODSThe Nationwide Inpatient Sample (NIS) was used (1998–2009). Patients were included in a spinal analysis cohort for instrumented spine surgery involving the cervical spine (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes 81.31–81.33, 81.01–81.03, 84.61–84.62, and 84.66) or lumbar spine (codes 81.04–81.08, 81.34–81.38, 84.64–84.65, and 84.68). A cranial analysis cohort consisted of patients receiving a parenchymal excision or lobectomy operation (codes 01.53 and 01.59). Surgeon specialization was measured using unique surgeon identifiers in the NIS and defined as the proportion of a surgeon’s total practice dedicated to cranial or spinal cases.RESULTSA total of 46,029 and 231,875 patients were identified in the cranial and spinal analysis cohorts, respectively. On multivariate analysis in the cranial analysis cohort (after controlling for overall surgeon volume, patient demographic data/comorbidities, hospital characteristics, and admitting source), each percentage-point increase in a surgeon’s cranial specialization (that is, the proportion of cranial cases) was associated with a 0.0060 reduction in the log odds of patient mortality (95% CI 0.0034–0.0086) and a 0.0042 reduction in the log odds of morbidity (95% CI 0.0032–0.0052). This resulted in a 15% difference in the predicted probability of mortality for neurosurgeons at the 75th versus the 25th percentile of cranial specialization. In the spinal analysis cohort, each percentage-point increase in a surgeon’s spinal specialization was associated with a 0.0122 reduction in the log odds of mortality (95% CI 0.0074–0.0170) and a 0.0058 reduction in the log odds of morbidity (95% CI 0.0049–0.0067). This resulted in a 26.8% difference in the predicted probability of mortality for neurosurgeons at the 75th versus the 25th percentile of spinal specialization.CONCLUSIONSFor both spinal and cranial surgery patient cohorts derived from the NIS database, increased surgeon specialization was significantly and independently associated with improved mortality and morbidity rates, even after controlling for overall case volume.
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- 2018
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22. Dose Reduction and Dose Management in Computed Tomography – State of the Art
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Konstantin Nikolaou, Ahmed E. Othman, Thomas Flohr, Roy P. Marcus, Dominik Zinsser, Fabian Bamberg, and Mike Notohamiprodjo
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medicine.medical_specialty ,Image quality ,Computer science ,Image processing ,Computed tomography ,Iterative reconstruction ,Radiation Dosage ,Sensitivity and Specificity ,Patient Positioning ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Software ,Radiation Monitoring ,Image Processing, Computer-Assisted ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Medical physics ,Radiometry ,medicine.diagnostic_test ,business.industry ,030220 oncology & carcinogenesis ,Dose reduction ,State (computer science) ,Tomography ,Tomography, X-Ray Computed ,business - Abstract
For years, the number of performed CT examinations has been rising. At the same time, computed tomography became more dose efficient. The aim of this article is to give an overview about the state of the art in dose reduction in CT and to highlight currently available tools in dose management. By performing a literature research on Pubmed regarding dose reduction in CT, relevant articles were identified and analyzed. Technical innovations with individual adaptation of tube current and voltage as well as iterative image reconstruction enable a considerable dose reduction with preserved image quality. At the same time, dedicated software tools are able to handle huge amounts of data and allow to optimize existing examination protocols. · CT examinations are increasingly performed and contribute considerably to non-natural radiation exposure.. · A correct indication is crucial for each CT examination.. · The examination protocol has to be tailored to the medical question and patient.. · Multiple technical innovations enable considerable dose reduction with constant image quality.. · Dose management with dedicated software tools gains importance..· Zinsser D, Marcus R, Othman AE et al. Dose reduction and dose management in computed tomography - State of the art. Fortschr Röntgenstr 2018; 190: 531 - 541. Die Zahl der durchgeführten CT-Untersuchungen steigt seit Jahren an. Zugleich ist die Computertomografie dosiseffizienter geworden. Das Ziel dieses Artikels ist es, einen Überblick über den aktuellen Stand der Dosisreduktion im CT zu geben und derzeit verfügbare Werkzeuge zum Dosismanagement vorzustellen. Mittels einer Literatursuche bei Pubmed wurden relevante Artikel, die sich mit der Dosisreduktion in der CT beschäftigen, identifiziert und ausgewertet. Durch technische Neuerungen mit individueller Anpassung von Röhrenstrom und -spannung sowie iterativer Bildrekonstruktion ist eine deutliche Dosisreduktion bei erhaltener Bildqualität möglich. Zugleich erlauben entsprechende Softwaretools eine weitere Optimierung bestehender Untersuchungsprotokolle, wobei auch große Datenmengen mit wenig Aufwand verarbeitet werden können. · CT-Untersuchungen werden immer häufiger durchgeführt und tragen erheblich zur nicht-natürlichen Strahlenbelastung bei.. · Grundlage jeder CT-Untersuchung ist die korrekte Indikationsstellung.. · Das Untersuchungsprotokoll muss auf die Fragestellung und den Patienten zugeschnitten werden.. · Zahlreiche technische Neuerungen erlauben eine deutliche Dosisreduktion bei erhaltener Bildqualität.. · Dosismanagement mittels entsprechender Software gewinnt zunehmend an Bedeutung..· Zinsser D, Marcus R, Othman AE et al. Dose reduction and dose management in computed tomography – State of the art. Fortschr Röntgenstr 2018; 190: 531 – 541.
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- 2018
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23. Applicability and accuracy of pretest probability calculations implemented in the NICE clinical guideline for decision making about imaging in patients with chest pain of recent onset
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Jean Pierre Laissy, Gianluca Pontone, Jörg Hausleiter, Juhani Knuuti, Lily Honoris, Mario J. Garcia, Hiroyuki Niinuma, Jonathan Leipsic, Harald Brodoefel, Daniele Andreini, Matthijs F.L. Meijs, R.R. Buechel, Eugenio Martuscelli, Jean-Claude Tardif, Lin Yang, Ashraf Hamdan, Thorsten R. C. Johnson, Robert Haase, Said Ghostine, Simone Muraglia, Peter Schlattmann, U. Joseph Schoepf, Shona M.M. Jenkins, Michael Laule, Koen Nieman, Philipp A. Kaufmann, Bjørn Arild Halvorsen, Carlos E. Rochitte, Robert Roehle, David A. Halon, Hans Mickley, Viktoria Wieske, Sebastian Leschka, Konstantin Nikolaou, Marc Dewey, David E. Bush, Axel Cosmus Pyndt Diederichsen, Abbas Arjmand Shabestari, Bernhard Gerber, Bjarne L. Nørgaard, Yung-Liang Wan, Arthur J.H.A. Scholte, Kristian A. Øvrehus, Johannes Rixe, Christoph Langer, John Hoe, Zhaoqi Zhang, Reda Jakamy, Benjamin J.W. Chow, Mehraj Sheikh, Hatem Alkadhi, Geir R. Ulimoen, Melvin E. Clouse, Pascal Gueret, Roy P. Marcus, Georg M. Schuetz, Albert de Roos, Narinder Paul, Akira Sato, Willem B. Meijboom, David Maintz, Vladimir Mendoza Rodriguez, Elke Zimmermann, Bernhard A. Herzog, Nuno Bettencourt, Kai Sun, Cardiology, Radiology & Nuclear Medicine, UCL - SSS/IREC/CARD - Pôle de recherche cardiovasculaire, and UCL - (SLuc) Service de pathologie cardiovasculaire
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Adult ,Male ,medicine.medical_specialty ,Chest Pain ,education ,Clinical Decision-Making ,Nice ,Mistake ,Pretest probability ,030204 cardiovascular system & hematology ,Chest pain ,Coronary artery disease ,Duke clinical score ,Multidetector computed tomography ,03 medical and health sciences ,0302 clinical medicine ,Risk Factors ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,In patient ,Medical physics ,030212 general & internal medicine ,Recent onset ,health care economics and organizations ,computer.programming_language ,Aged ,Probability ,business.industry ,Chest Pain/diagnostic imaging ,Published Erratum ,General Medicine ,Guideline ,Middle Aged ,humanities ,Pre- and post-test probability ,Cardiac Imaging Techniques ,Practice Guidelines as Topic ,NICE clinical guideline ,Female ,Radiology ,Guideline Adherence ,medicine.symptom ,business ,Tomography, X-Ray Computed ,computer - Abstract
Objectives: To analyse the implementation, applicability and accuracy of the pretest probability calculation provided by NICE clinical guideline 95 for decision making about imaging in patients with chest pain of recent onset. Methods: The definitions for pretest probability calculation in the original Duke clinical score and the NICE guideline were compared. We also calculated the agreement and disagreement in pretest probability and the resulting imaging and management groups based on individual patient data from the Collaborative Meta-Analysis of Cardiac CT (CoMe-CCT). Results: 4,673 individual patient data from the CoMe-CCT Consortium were analysed. Major differences in definitions in the Duke clinical score and NICE guideline were found for the predictors age and number of risk factors. Pretest probability calculation using guideline criteria was only possible for 30.8 % (1,439/4,673) of patients despite availability of all required data due to ambiguity in guideline definitions for risk factors and age groups. Agreement regarding patient management groups was found in only 70 % (366/523) of patients in whom pretest probability calculation was possible according to both models. Conclusions: Our results suggest that pretest probability calculation for clinical decision making about cardiac imaging as implemented in the NICE clinical guideline for patients has relevant limitations. Key Points: • Duke clinical score is not implemented correctly in NICE guideline 95. • Pretest probability assessment in NICE guideline 95 is impossible for most patients. • Improved clinical decision making requires accurate pretest probability calculation. • These refinements are essential for appropriate use of cardiac CT.
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- 2018
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24. The Invention of the Favela by Licia do Prado Valladares
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Alan P. Marcus
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Geography, Planning and Development ,Earth-Surface Processes - Published
- 2021
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25. A Different Manifest Destiny: U.S. Southern Identity and Citizenship in Nineteenth-Century South America
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Alan P. Marcus
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History ,History and Philosophy of Science ,Anthropology ,media_common.quotation_subject ,Identity (social science) ,Electrical and Electronic Engineering ,Manifest destiny ,Citizenship ,Atomic and Molecular Physics, and Optics ,media_common - Published
- 2021
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26. Experimental characterization of the biaxial mechanical properties of porcine gastric tissue
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Christian J. Cyron, Mike Notohamiprodjo, F. A. Braeu, Konstantin Nikolaou, Sebastian Brandstaeter, M. Steigenberger, Roy P. Marcus, and Roland C. Aydin
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0301 basic medicine ,Pathology ,medicine.medical_specialty ,Materials science ,Swine ,0206 medical engineering ,Biomedical Engineering ,02 engineering and technology ,Biomaterials ,03 medical and health sciences ,Health problems ,medicine ,Animals ,Humans ,Gastric wall ,Inverse analysis ,Antrum ,Physiological function ,Stomach ,digestive, oral, and skin physiology ,Anatomy ,020601 biomedical engineering ,Biomechanical Phenomena ,Gastric Tissue ,030104 developmental biology ,medicine.anatomical_structure ,Mechanics of Materials ,Anisotropy ,Stress, Mechanical - Abstract
Health problems related to the stomach are among the most important sources of morbidity in industrialized countries. There is evidence that mechanics may play an important role in various such pathologies. However, so far experimental data characterizing the mechanical properties of gastric tissue remain scarce, which significantly limits our understanding of the mechanics of the stomach. To help close this gap, we performed biaxial mechanical tests of porcine gastric tissue patches. Our experiments reveal a considerable anisotropy and different mechanical properties in the three major regions of the stomach (fundus, corpus, antrum). Moreover, they demonstrate that the mechanical properties of the gastric wall and the physiological function of the different regions of the stomach are closely related. This finding suggests that further examination of the mechanics of the gastric wall may indeed be a promising avenue of research towards a better understanding of the organic causes of frequent health problems related to the stomach.
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- 2017
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27. Population geographies of Brazil
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Alan P. Marcus
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education.field_of_study ,Anthropology ,Population ,Sociology ,Geographer ,Viewpoints ,education - Published
- 2019
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28. Image Quality of a Novel Frequency Selective Nonlinear Blending Algorithm
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Christoph Schabel, Hendrik Ditt, Malte N. Bongers, Marius Horger, Christopher Kloth, Konstantin Nikolaou, Georg Bier, and Roy P. Marcus
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Image quality ,media_common.quotation_subject ,Contrast Media ,Signal-To-Noise Ratio ,Imaging phantom ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Absorptiometry, Photon ,0302 clinical medicine ,Iodinated contrast ,Region of interest ,Image Processing, Computer-Assisted ,Humans ,Contrast (vision) ,Radiology, Nuclear Medicine and imaging ,media_common ,Mathematics ,Phantoms, Imaging ,business.industry ,Attenuation ,General Medicine ,Radiographic Image Enhancement ,Signal-to-noise ratio (imaging) ,030220 oncology & carcinogenesis ,Tomography, X-Ray Computed ,Nuclear medicine ,business ,Algorithm ,Algorithms - Abstract
OBJECTIVE Aim of this ex vivo phantom study was to evaluate the contrast enhancement applying a new frequency split nonlinear blending algorithm (best contrast [BC]) and to compare it with standard 120-kV single-energy computed tomography (SECT) images, as well as with low-kiloelectron volt monoenergetic extrapolations (Mono+40-100keV) from dual-energy CT (DECT) and with low-kilovolt (70-100 kV) SECT acquisitions. MATERIALS AND METHODS A dilution series of iodinated contrast material-filled syringes was centered in an attenuation phantom and was scanned with SECT70-120kV and DECT80-100/Sn150. Monoenergetic images (40-100 keV) were reconstructed, and a new manual frequency split nonlinear blending algorithm (BC) was applied to SECT70kV and SECT120kV images. Manual BC settings were set to simulate a reading situation with fixed overall best values (FVBC120kV) as well as to achieve best possible values for each syringe (BVBC120kV) for maximum contrast enhancement. Contrast-to-noise ratios (CNRs) were used as an objective region of interest-based image analysis parameter. Two radiologists evaluated the detectability of hyperdense and hypodense syringes (Likert). Results were compared between SECT70-100kV, Mono+40-100keV, and DECT80-100/Sn150kV, as well as FVBC120kV, BVBC120kV, and BC70kV. RESULTS Highest CNR without BC was detected at SECT70kV (5.04 ± 0.12) and Mono+40keV (4.40 ± 0.11). FVBC and BVBC images allow a significant increase of CNR compared with SECT120kV (CNRBVBC, 5.21 ± 0.15; CNRFVBC, 5.12 ± 0.16; CNRSECT120kV, 2.5 ± 0.08; all P ≤ 0.01). There was no significant difference in CNR between BVBC and FVBC. Averaged CNR in BVBC and FVBC was significantly higher compared with Mono+40-100keV (all P ≤ 0.01). Compared with SECT70kV, averaged CNR in BVBC and FVBC show no significant differences. BVBC70kV (7.67 ± 0.17) significantly increases CNR in SECT70kV up to 213%.Subjective image analysis showed an interobserver agreement of 0.63 to 0.83 (κ), confirming the superiority of BC in detecting hyperdense and hypodense syringes, when compared with SECT120kV. Compared with SECT120kV, BVBC70kV was scored highest, followed by SECT70kV. BVBC showed higher scores when comparing to Mono+40keV, however almost identical to those of SECT70kV. Scores of FVBC were slightly lower than SECT70kV, but in the range of Mono+40keV. CONCLUSIONS The new frequency split nonlinear blending algorithm with fixed settings offers a superior differentiation of contrast levels from low- to high-contrast settings. Using the optimal settings, this algorithm shows an equivalent contrast enhancement when compared with SECT70kV. Because of the non-DECT-based algorithm of BC, the new method of contrast enhancement seems to be particularly valuable for implementation in CT systems not equipped for dual-energy or spectral CT imaging.
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- 2016
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29. Cumulative Intracranial Tumor Volume (CITV) Enhances the Prognostic Value of the Lung-Specific Graded Prognostic Assessment (GPA) Model
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Logan P. Marcus, Brandon A. McCutcheon, Takao Koiso, Brian R. Hirshman, Jona A. Hattangadi-Gluth, Bob S. Carter, Clark C. Chen, Masaaki Yamamoto, David D. Gonda, and Deborah C. Marshall
- Subjects
Adult ,Male ,Oncology ,medicine.medical_specialty ,Lung Neoplasms ,medicine.medical_treatment ,Brain tumor ,Radiosurgery ,03 medical and health sciences ,0302 clinical medicine ,Predictive Value of Tests ,Internal medicine ,medicine ,Humans ,Karnofsky Performance Status ,Lung cancer ,Aged ,Proportional Hazards Models ,Retrospective Studies ,Brain Neoplasms ,business.industry ,Proportional hazards model ,Retrospective cohort study ,Middle Aged ,Prognosis ,medicine.disease ,Confidence interval ,Tumor Burden ,Surgery ,030220 oncology & carcinogenesis ,Predictive value of tests ,Female ,Neurology (clinical) ,Neoplasm Grading ,business ,030217 neurology & neurosurgery ,Brain metastasis - Abstract
BACKGROUND Management of patients afflicted with brain metastasis requires tailoring of therapeutic strategies based on survival expectations. Therefore, the development of prognostic indices is of critical importance in this patient population. OBJECTIVE To determine whether the cumulative intracranial tumor volume (CITV) of brain metastasis augments the prognostic value of the lung-specific Graded Prognostic Assessment (GPA) index. METHODS Patient data were derived from 365 lung cancer patients with brain metastasis who were consecutively treated with stereotactic radiosurgery at the University of California, San Diego/San Diego Gamma Knife Center. CITV was analyzed to determine the volume cutoff that maximized sensitivity and specificity for 1-year survival. Multivariate Cox proportional hazard modeling was performed, and overall survival was estimated by the Kaplan-Meier method risk stratifying with or without this optimal CITV. The prognostic value of these models (lung-specific GPA ± CITV) was quantitatively compared with the use of net reclassification improvement (>0) and integrated discrimination improvement. RESULTS For the University of California, San Diego/San Diego Gamma Knife Center cohort, the CITV cutoff that had the greatest survival discrimination at 1 year was 4 cm. The addition of CITV to the lung-specific GPA indexes significantly improved the prognostic value of lung-specific GPA, with net reclassification improvement >0 of 0.430 (95% confidence interval, 0.228-0.629) and integrated discrimination improvement of 0.029 (95% confidence interval, 0.004-0.073). These findings were validated in an independent cohort of 1638 lung cancer patients with brain metastasis who were treated with stereotactic radiosurgery at the Katsuta Hospital Mito Gamma House in Japan. CONCLUSION In independent cohorts, the addition of CITV to the lung-specific GPA index significantly improved the prognostic value of this index. ABBREVIATIONS AUC, area under the receiver-operating characteristic curveBM, brain metastasisCITV, cumulative intracranial tumor volumeds-GPA, disease-specific Graded Prognostic AssessmentGPA, Graded Prognostic AssessmentIDI, integrated discrimination improvementKHMGH, Katsuta Hospital Mito Gamma HouseKPS, Karnofsky Performance StatusNRI, net reclassification improvementROC, receiver-operating characteristic curveSRS, stereotactic radiosurgeryUCSD/SDGKC, University of California, San Diego/San Diego Gamma Knife Center.
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- 2016
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30. Evidencia científica reciente y avances técnicos en la tomografía computarizada cardiovascular
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Christer Ruff, Tobias Geisler, Christof Burgstahler, Mike Notohamiprodjo, Fabian Bamberg, Stephen Schroeder, Roy P. Marcus, and Konstantin Nikolaou
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03 medical and health sciences ,0302 clinical medicine ,business.industry ,Medicine ,030204 cardiovascular system & hematology ,Cardiology and Cardiovascular Medicine ,business ,Humanities ,030218 nuclear medicine & medical imaging - Abstract
Resumen En los ultimos anos, la coronariografia (o angiografia coronaria) por tomografia computarizada se ha asentado cada vez mas como una modalidad diagnostica segura y no invasiva para la evaluacion de la antomia del arbol arterial coronario, que aporta ventajas diagnosticas, en especial para pacientes con probabilidad pretest baja o intermedia de la enfermedad. Actualmente hay cada vez mas evidencia de grandes ensayos aleatorizados sobre la influencia diagnostica de la angiotomografia computarizada en el manejo de los pacientes con sindromes de dolor toracico agudo y cronico. Al mismo tiempo, los avances tecnicos han reducido sustancialmente los efectos adversos y los factores limitantes, como la exposicion a la radiacion, la cantidad de medio de contraste yodado que se aplica y el tiempo de exploracion, lo cual la hace apropiada para aplicaciones clinicas mas amplias. En este trabajo se revisan los avances mas recientes en la tecnologia de la tomografia computarizada y se describe la evidencia cientifica existente sobre el uso de la angiotomografia computarizada cardiaca en la evaluacion de los pacientes con sindromes de dolor toracico agudo y cronico.
- Published
- 2016
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31. Recent Scientific Evidence and Technical Developments in Cardiovascular Computed Tomography
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Stephen Schroeder, Christer Ruff, Konstantin Nikolaou, Roy P. Marcus, Mike Notohamiprodjo, Fabian Bamberg, Tobias Geisler, and Christof Burgstahler
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Chest Pain ,Acute coronary syndrome ,medicine.medical_specialty ,Computed Tomography Angiography ,Contrast Media ,Iodinated Contrast Agent ,030204 cardiovascular system & hematology ,Chest pain ,030218 nuclear medicine & medical imaging ,Scientific evidence ,03 medical and health sciences ,0302 clinical medicine ,Image Processing, Computer-Assisted ,Humans ,Medicine ,Adverse effect ,Computed tomography angiography ,medicine.diagnostic_test ,business.industry ,General Medicine ,medicine.disease ,Pre- and post-test probability ,Cardiac Imaging Techniques ,Cardiovascular Diseases ,Radiology ,medicine.symptom ,Tomography, X-Ray Computed ,business - Abstract
In recent years, coronary computed tomography angiography has become an increasingly safe and noninvasive modality for the evaluation of the anatomical structure of the coronary artery tree with diagnostic benefits especially in patients with a low-to-intermediate pretest probability of disease. Currently, increasing evidence from large randomized diagnostic trials is accumulating on the diagnostic impact of computed tomography angiography for the management of patients with acute and stable chest pain syndrome. At the same time, technical advances have substantially reduced adverse effects and limiting factors, such as radiation exposure, the amount of iodinated contrast agent, and scanning time, rendering the technique appropriate for broader clinical applications. In this work, we review the latest developments in computed tomography technology and describe the scientific evidence on the use of cardiac computed tomography angiography to evaluate patients with acute and stable chest pain syndrome.
- Published
- 2016
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32. Management patterns of patients with cerebral metastases who underwent multiple stereotactic radiosurgeries
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Bob S. Carter, John F. Alksne, Kenneth Ott, Logan P. Marcus, Brandon A. McCutcheon, Clark C. Chen, Masaaki Yamamoto, Deborah C. Marshall, Takao Koiso, Teddy E. Kim, Steven J. Goetsch, and Jona A. Hattangadi-Gluth
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Cancer Research ,medicine.medical_specialty ,Systemic disease ,Neurology ,Stereotactic Radiosurgeries ,Radiosurgery ,03 medical and health sciences ,0302 clinical medicine ,Interquartile range ,medicine ,Humans ,Aged ,Retrospective Studies ,Lung ,Brain Neoplasms ,business.industry ,Melanoma ,Age Factors ,Brain ,Disease Management ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,Survival Analysis ,Tumor Burden ,Surgery ,Treatment Outcome ,medicine.anatomical_structure ,Oncology ,030220 oncology & carcinogenesis ,Retreatment ,Cohort ,Neurology (clinical) ,Radiology ,business ,030217 neurology & neurosurgery ,Brain metastasis - Abstract
With escalating focus on cost containment, there is increasing scrutiny on the practice of multiple stereotactic radiosurgeries (SRSs) for patients with cerebral metastases distant to the initial tumor site. Our goal was to determine the survival patterns of patients with cerebral metastasis who underwent multiple SRSs. We retrospectively analyzed survival outcomes of 801 patients with 3683 cerebral metastases from primary breast, colorectal, lung, melanoma and renal histologies consecutively treated at the University of California, San Diego/San Diego Gamma Knife Center (UCSD/SDGKC), comparing the survival pattern of patients who underwent a single (n = 643) versus multiple SRS(s) (n = 158) for subsequent cerebral metastases. Findings were recapitulated in an independent cohort of 2472 patients, with 26,629 brain metastases treated with SRS at the Katsuta Hospital Mito GammaHouse (KHMGH). For the UCSD/SDGKC cohort, no significant difference in median survival was found for patients undergoing 1, 2, 3, or ≥4 SRS(s) (median survival of 167, 202, 129, and 127 days, respectively). Median intervals between treatments consistently ranged 140–178 days irrespective of the number of SRS(s) (interquartile range 60–300; p = 0.25). Patients who underwent >1 SRSs tend to be younger, with systemic disease control, harbor lower cumulative tumor volume but increased number of metastases, and have primary melanoma (p
- Published
- 2016
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33. The Brazil Reader. History, Culture, Politics ed. by James N. Green, Victoria Langland, Lilia Moritz Schwarcz
- Author
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Alan P. Marcus
- Subjects
Politics ,media_common.quotation_subject ,Geography, Planning and Development ,Art history ,Art ,Earth-Surface Processes ,media_common - Published
- 2020
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34. Editorial: JLAG's Expanded Editorial Team
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Eric D. Carter, Diana Tung, Jorn Seemann, Eugenio Arima, Martha G. Bell, Jessica Budds, Gabriela Valdivia, Alan P. Marcus, and Johnny Finn
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Editorial team ,Political science ,Geography, Planning and Development ,Earth-Surface Processes ,Management - Published
- 2020
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35. Religious Literacy in American Education
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Benjamin P. Marcus
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American education ,Lived religion ,Gender studies ,Sociology ,Religious literacy ,Religious identity - Abstract
Popular definitions of religious literacy don’t capture the reality of lived religion in a plural age. Using language as a metaphor for religion, this chapter differentiates between religious fluency among co-religionists and the ability to read and interpret the vocabulary of the “language” of the religious other. Whereas advocates for biblical literacy and world religions courses often reinforce an essentialist understanding of religion that presents only the “standard” version of a language, this chapter suggests an alternative 3B Framework that encourages students to consider how the interrelationship of belief, behavior, and belonging creates religious “dialects.” A pedagogy built around the 3B Framework encourages students to compare and contrast the construction of religious languages in a linguistic mode, analyzing the importance of belief, behavior, and belonging for individuals or communities. This framework opens possibilities for inter-religious dialogue between “multilingual linguists” who can engage the most meaningful aspects of interlocutors’ religious identity.
- Published
- 2018
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36. Correction to: Applicability and accuracy of pretest probability calculations implemented in the NICE clinical guideline for decision making about imaging in patients with chest pain of recent onset
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Willem B. Meijboom, Jean-Claude Tardif, Thorsten R. C. Johnson, Robert Haase, Philipp A. Kaufmann, Robert Roehle, Bernhard Gerber, U. Joseph Schoepf, Bernhard A. Herzog, Marc Dewey, Narinder Paul, Jonathan Leipsic, Abbas Arjmand Shabestari, Bjarne L. Nørgaard, Hatem Alkadhi, Yung-Liang Wan, Geir R. Ulimoen, David Maintz, Koen Nieman, Elke Zimmermann, Jean Pierre Laissy, Juhani Knuuti, Lily Honoris, Kristian A. Øvrehus, Arthur J. Scholte, Hiroyuki Niinuma, Melvin E. Clouse, Georg M. Schuetz, Matthijs F.L. Meijs, Akira Sato, Albert de Roos, Vladimir Mendoza Rodriguez, Daniele Andreini, David E. Bush, Axel Cosmus Pyndt Diederichsen, Lin Yang, Ashraf Hamdan, Said Ghostine, Christoph Langer, Sebastian Leschka, David A. Halon, Carlos E. Rochitte, Zhaoqi Zhang, Viktoria Wieske, Peter Schlattmann, Simone Muraglia, Benjamin J.W. Chow, Pascal Gueret, R.R. Buechel, Roy P. Marcus, Kai Sun, Gianluca Pontone, Bjørn Arild Halvorsen, Michael Laule, Jörg Hausleiter, Hans Mickley, Shona M.M. Jenkins, Konstantin Nikolaou, Harald Brodoefel, Eugenio Martuscelli, John Hoe, Mehraj Sheikh, Nuno Bettencourt, Mario J. Garcia, Reda Jakamy, Johannes Rixe, UCL - SSS/IREC/CARD - Pôle de recherche cardiovasculaire, and UCL - (SLuc) Service de pathologie cardiovasculaire
- Subjects
medicine.medical_specialty ,business.industry ,Nice ,Mistake ,General Medicine ,Guideline ,Chest pain ,Pre- and post-test probability ,Radiology Nuclear Medicine and imaging ,medicine ,Radiology, Nuclear Medicine and imaging ,In patient ,Radiology ,medicine.symptom ,Recent onset ,business ,computer ,computer.programming_language - Abstract
The original version of this article, published on 19 March 2018, unfortunately contained a mistake. The following correction has therefore been made in the original: The names of the authors Philipp A. Kaufmann, Ronny Ralf Buechel and Bernhard A. Herzog were presented incorrectly.
- Published
- 2018
37. Feasibility of free-breathing, GRAPPA-based, real-time cardiac cine assessment of left-ventricular function in cardiovascular patients at 3 T
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Harald Kramer, Xiaomei Zhu, Holger Hetterich, Fabian Bamberg, Christopher L. Schlett, Maximilian F. Reiser, Roy P. Marcus, Mike Notohamiprodjo, Felix Schwab, Daniel Theisen, and Konstantin Nikolaou
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Adult ,Male ,Intraclass correlation ,Cardiomyopathy ,Magnetic Resonance Imaging, Cine ,Ventricular Function, Left ,Ventricular Dysfunction, Left ,Heart Rate ,Predictive Value of Tests ,Cardiac magnetic resonance imaging ,Image Interpretation, Computer-Assisted ,Heart rate ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,cardiovascular diseases ,Prospective cohort study ,Aged ,medicine.diagnostic_test ,Ventricular function ,business.industry ,Reproducibility of Results ,General Medicine ,Middle Aged ,medicine.disease ,Cohort ,Respiratory Mechanics ,cardiovascular system ,Feasibility Studies ,Female ,business ,Nuclear medicine ,Free breathing ,circulatory and respiratory physiology - Abstract
To determine the feasibility of free-breathing, GRAPPA-based, real-time (RT) cine 3T cardiac magnetic resonance imaging (MRI) with high acceleration factors for the assessment of left-ventricular function in a cohort of patients as compared to conventional segmented cine imaging.In this prospective cohort study, subjects with various cardiac conditions underwent MRI involving two RT cine sequences (high resolution and low resolution) and standard segmented cine imaging. Standard qualitative and quantitative parameters of left-ventricular function were quantified.Among 25 subjects, 24 were included in the analysis (mean age: 50.5±21 years, 67% male, 25% with cardiomyopathy). RT cine derived quantitative parameters of volumes and left ventricular mass were strongly correlated with segmented cine imaging (intraclass correlation coefficient [ICC]:0.72 for both RT cines) but correlation for peak ejection and filling rates were moderate to poor for both RT cines (ICC0.40). Similarly, RT cines significantly underestimated peak ejection and filling rates (103.2±178 ml/s). Among patient-related factors, heart rate was strongly predictive for deviation of measurements (p0.05).RT cine MRI at 3T is feasible for qualitative and quantitative assessment of left ventricular function for low and high-resolution sequences but results in significant underestimation of systolic function, peak ejection and filling rates.
- Published
- 2015
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38. MP01-08 USE OF DEDICATED STONE ANALYSIS SOFTWARE TO ASSESS URINARY STONE SIZE: TOWARDS SEMI-AUTOMATED METRICS TO ENHANCE PREDICTION OF SPONTANEOUS STONE PASSAGE
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Roy P. Marcus, Shane Dirks, Cynthia H. McCollough, John C. Lieske, John Knoedler, Scott Heiner, and Joel G. Fletcher
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03 medical and health sciences ,0302 clinical medicine ,Software ,business.industry ,030220 oncology & carcinogenesis ,Urology ,Urinary stone ,030232 urology & nephrology ,Medicine ,business ,Stone analysis ,Construction engineering - Published
- 2017
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39. Automatic vertebral bodies detection of x-ray images using invariant multiscale template matching
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Luke Macyszyn, Diane Villaroman, Mark A. Attiah, Mona Sharifi Sarabi, Joel S. Beckett, Bilwaj Gaonkar, Logan P. Marcus, Christine S. Ahn, Cauligi S. Raghavendra, and Diana Babayan
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Similarity (geometry) ,medicine.diagnostic_test ,Computer science ,business.industry ,Template matching ,Magnetic resonance imaging ,Image segmentation ,Field (computer science) ,030218 nuclear medicine & medical imaging ,Gross examination ,03 medical and health sciences ,0302 clinical medicine ,Medical imaging ,medicine ,Computer vision ,Artificial intelligence ,Invariant (mathematics) ,business ,Focus (optics) - Abstract
Lower back pain and pathologies related to it are one of the most common results for a referral to a neurosurgical clinic in the developed and the developing world. Quantitative evaluation of these pathologies is a challenge. Image based measurements of angles/vertebral heights and disks could provide a potential quantitative biomarker for tracking and measuring these pathologies. Detection of vertebral bodies is a key element and is the focus of the current work. From the variety of medical imaging techniques, MRI and CT scans have been typically used for developing image segmentation methods. However, CT scans are known to give a large dose of x-rays, increasing cancer risk [8]. MRI can be substituted for CTs when the risk is high [8] but are difficult to obtain in smaller facilities due to cost and lack of expertise in the field [2]. X-rays provide another option with its ability to control the x-ray dosage, especially for young people, and its accessibility for smaller facilities. Hence, the ability to create quantitative biomarkers from x-ray data is especially valuable. Here, we develop a multiscale template matching, inspired by [9], to detect centers of vertebral bodies from x-ray data. The immediate application of such detection lies in developing quantitative biomarkers and in querying similar images in a database. Previously, shape similarity classification methods have been used to address this problem, but these are challenging to use in the presence of variation due to gross pathology and even subtle effects [1].
- Published
- 2017
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40. Long-term follow-up of unruptured intracranial aneurysms repaired in California
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Bob S. Carter, David C. Chang, Alexander A. Khalessi, David D. Gonda, Logan P. Marcus, Brandon A. McCutcheon, Clark C. Chen, and Abraham Noorbakhsh
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medicine.medical_specialty ,Endovascular coiling ,business.industry ,Long term follow up ,medicine.medical_treatment ,Significant difference ,Perioperative ,Clipping (medicine) ,Surgery ,cardiovascular system ,Unruptured cerebral aneurysm ,Medicine ,In patient ,cardiovascular diseases ,Radiology ,Health planning ,business - Abstract
Object Using a database that enabled longitudinal follow-up, the authors assessed the long-term outcomes of unruptured cerebral aneurysms repaired by clipping or coiling. Methods An observational analysis of the California Office of Statewide Health Planning and Development (OSHPD) database, which follows patients longitudinally in time and through multiple hospitalizations, was performed for all patients initially treated for an unruptured cerebral aneurysm in the period from 1998 to 2005 and with follow-up data through 2009. Results Nine hundred forty-four cases (36.5%) were treated with endovascular coiling, 1565 cases (60.5%) were surgically clipped, and 76 cases were treated with both coiling and clipping. There was no significant difference in any demographic variable between the two treatment groups except for age (median: 55 years for the clipped group, 58 years for the coiled group, p < 0.001). Perioperative (30-day) mortality was 1.1% in patients with coiled aneurysms compared with 2.3% in those with clipped aneurysms (p = 0.048). The median follow-up was 7 years (range 4–12 years). At the last follow-up, 153 patients (16.2%) in the coiled group had died compared with 244 (15.6%) in the clipped group (p = 0.693). The adjusted hazard ratio for death at the long-term follow-up was 1.14 (95% CI 0.9–1.4, p = 0.282) for patients with endovascularly treated aneurysms. The incidence of intracranial hemorrhage was similar in the two treatment groups (5.9% clipped vs 4.8% coiled, p = 0.276). One hundred ninety-three patients (20.4%) with coiled aneurysms underwent additional hospitalizations for aneurysm repair procedures compared with only 136 patients (8.7%) with clipped aneurysms (p < 0.001). Cumulative hospital costs per patient for admissions involving aneurysm repair procedures were greater in the clipped group (median cost $98,260 vs $81,620, p < 0.001) through the follow-up. Conclusions For unruptured cerebral aneurysms, an observed perioperative survival advantage for endovascular coiling relative to that for surgical clipping was lost on long-term follow-up, according to data from an administrative database of patients who were not randomly allocated to treatment type. A cost advantage of endovascular treatment was maintained even though endovascularly treated patients were more likely to undergo subsequent hospitalizations for additional aneurysm repair procedures. Rates of aneurysm rupture following treatment were similar in the two groups.
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- 2014
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41. Incidence and predictors of 30-day readmission for patients discharged home after craniotomy for malignant supratentorial tumors in California (1995–2010)
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Abraham Noorbakhsh, Bob S. Carter, David D. Gonda, Ralitza P. Parina, Logan P. Marcus, Brandon A. McCutcheon, David C. Chang, and Clark C. Chen
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medicine.medical_specialty ,Multivariate analysis ,business.industry ,Incidence (epidemiology) ,medicine.medical_treatment ,Brain tumor ,Supratentorial Neoplasm ,MEDLINE ,medicine.disease ,Surgery ,Emergency medicine ,Health care ,medicine ,Diagnosis code ,business ,Craniotomy - Abstract
Object Hospital readmission within 30 days of discharge is a major contributor to the high cost of health care in the US and is also a major indicator of patient care quality. The purpose of this study was to investigate the incidence, causes, and predictors of 30-day readmission following craniotomy for malignant supratentorial tumor resection. Methods The longitudinal California Office of Statewide Health Planning & Development inpatient-discharge administrative database is a data set that consists of 100% of all inpatient hospitalizations within the state of California and allows each patient to be followed throughout multiple inpatient hospital stays, across multiple institutions, and over multiple years (from 1995 to 2010). This database was used to identify patients who underwent a craniotomy for resection of primary malignant brain tumors. Causes for unplanned 30-day readmission were identified by principle ICD-9 diagnosis code and multivariate analysis was used to determine the independent effect of various patient factors on 30-day readmissions. Results A total of 18,506 patients received a craniotomy for the treatment of primary malignant brain tumors within the state of California between 1995 and 2010. Four hundred ten patients (2.2%) died during the index surgical admission, 13,586 patients (73.4%) were discharged home, and 4510 patients (24.4%) were transferred to another facility. Among patients discharged home, 1790 patients (13.2%) were readmitted at least once within 30 days of discharge, with 27% of readmissions occurring at a different hospital than the initial surgical institution. The most common reasons for readmission were new onset seizure and convulsive disorder (20.9%), surgical infection of the CNS (14.5%), and new onset of a motor deficit (12.8%). Medi-Cal beneficiaries were at increased odds for readmission relative to privately insured patients (OR 1.52, 95% CI 1.20–1.93). Patients with a history of prior myocardial infarction were at an increased risk of readmission (OR 1.64, 95% CI 1.06–2.54) as were patients who developed hydrocephalus (OR 1.58, 95% CI 1.20–2.07) or venous complications during index surgical admission (OR 3.88, 95% CI 1.84–8.18). Conclusions Using administrative data, this study demonstrates a baseline glioma surgery 30-day readmission rate of 13.2% in California for patients who are initially discharged home. This paper highlights the medical histories, perioperative complications, and patient demographic groups that are at an increased risk for readmission within 30 days of home discharge. An analysis of conditions present on readmission that were not present at the index surgical admission, such as infection and seizures, suggests that some readmissions may be preventable. Discharge planning strategies aimed at reducing readmission rates in neurosurgical practice should focus on patient groups at high risk for readmission and comprehensive discharge planning protocols should be implemented to specifically target the mitigation of potentially preventable conditions that are highly associated with readmission.
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- 2014
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42. Tracer kinetic modeling in myocardial perfusion quantification using MRI
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Daniel Theisen, Konstantin Nikolaou, Michael Ingrisch, Christopher Gliemi, Roy P. Marcus, Kristof Hildebrandt, Fabian Bamberg, Christine Adrion, Maximilian F. Reiser, and Felix Schwab
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Tracer kinetic ,Quantification methods ,Time frame ,Data acquisition ,business.industry ,Deconvolution analysis ,Medicine ,Radiology, Nuclear Medicine and imaging ,Deconvolution ,Nuclear medicine ,business ,Perfusion ,Cardiac perfusion - Abstract
Purpose To investigate and compare several quantification methods of myocardial perfusion measurements, paying special attention to the relation between the techniques and the required measurement duration. Methods Seven patients underwent contrast-enhanced rest and stress cardiac perfusion measurements at 3T. Three slices were acquired in each patient and were divided into 16 segments, leading to 112 rest and stress data curves, which were analyzed using various tracer kinetic models as well as a model-free deconvolution. Plasma flow, plasma volume, and myocardial perfusion reserve were analyzed for the complete acquisition as well as for the first pass data only. Results Deconvolution analysis yielded stable results for both rest and stress analysis, while Fermi and one compartment models agree well for first pass data (rest measurements only) and prolonged data acquisition (stress measurements only). More complex models do not yield satisfactory results for the short measurement times investigated in this study. Conclusions When performing MRI-based quantification of myocardial perfusion, care must be taken that the method used is appropriate for the time frame under investigation. When a numerical deconvolution is used instead of tracer kinetic models, more stable results are obtained. Magn Reson Med 73:1206–1215, 2015. © 2014 Wiley Periodicals, Inc.
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- 2014
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43. Dynamic Myocardial CT Perfusion Imaging for Evaluation of Myocardial Ischemia as Determined by MR Imaging
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Kristof Hildebrandt, Florian Schwarz, Hans-Christoph Becker, Daniel Theisen, Maximilian F. Reiser, Konstantin Nikolaou, Franz von Ziegler, Martin Greif, Roy P. Marcus, Fabian Bamberg, Alexander Becker, Bernhard Bischoff, Kerstin Bauner, and Thorsten R. C. Johnson
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Male ,medicine.medical_specialty ,cardiac MR ,Myocardial Infarction ,cardiac CT ,Perfusion scanning ,Coronary Artery Disease ,ischemia ,Coronary Angiography ,Diagnosis, Differential ,Coronary artery disease ,Coronary circulation ,Myocardial perfusion imaging ,Predictive Value of Tests ,Coronary Circulation ,Internal medicine ,Multidetector Computed Tomography ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,Prospective Studies ,infarct ,Myocardial infarction ,Aged ,medicine.diagnostic_test ,business.industry ,Myocardial Perfusion Imaging ,Magnetic resonance imaging ,Middle Aged ,medicine.disease ,Magnetic Resonance Imaging ,medicine.anatomical_structure ,Regional Blood Flow ,Radiology Nuclear Medicine and imaging ,Angiography ,Cardiology ,Feasibility Studies ,Female ,Cardiology and Cardiovascular Medicine ,business ,Nuclear medicine ,Perfusion ,myocardial perfusion - Abstract
Objectives The aim of this study was to determine the feasibility of computed tomography (CT)-based dynamic myocardial perfusion imaging for the assessment of myocardial ischemia and infarction compared with cardiac magnetic resonance (CMR). Background Sequential myocardial CT perfusion imaging has emerged as a novel imaging technique for the assessment of myocardial hypoperfusion. Methods We prospectively enrolled subjects with known coronary artery disease who underwent adenosine-mediated stress dynamic dual-source CT (100 kV, 320 mAs/rot) and CMR (3-T). Estimated myocardial blood flow (eMBF) and estimated myocardial blood volume (eMBV) were derived from CT images, using a model-based parametric deconvolution technique. The values were independently related to perfusion defects (ischemic and/or infarcted myocardial segments) as visually assessed during rest/stress and late gadolinium enhancement CMR. Conventional measures of diagnostic accuracy and differences in eMBF/eMBV were determined. Results Of 38 enrolled subjects, 31 (mean age 70.4 ± 9.3 years; 77% men) completed both CT and CMR protocols. The prevalence of ischemic and infarcted myocardial segments detected by CMR was moderate (11.6%, n = 56 and 12.6%, n = 61, respectively, of 484 analyzed segments, with 8.4% being transmural). The diagnostic accuracy of CT for the detection of any perfusion defect was good (eMBF threshold, 88 ml/mg/min; sensitivity, 77.8% [95% confidence interval (CI): 69% to 85%]; negative predictive value, 91.3% [95% CI: 86% to 94%]) with moderate positive predictive value (50.6% [95% CI: 43% to 58%] and specificity (75.41% [95% CI: 70% to 79%]). Higher diagnostic accuracy was observed for transmural perfusion defects (sensitivity 87.8%; 95% CI: 74% to 96%) and infarcted segments (sensitivity 85.3%; 95% CI: 74% to 93%). Although eMBF in high-quality examinations was lower but not different between ischemic and infarcted segments (72.3 ± 18.7 ml/100 ml/min vs. 73.1 ± 31.9 ml/100 ml/min, respectively, p > 0.05), eMBV was significantly lower in infarcted segments compared with ischemic segments (11.3 ± 3.3 ml/100 ml vs. 18.4 ± 2.8 ml/100 ml, respectively; p Conclusions Compared with CMR, dynamic stress CT provides good diagnostic accuracy for the detection of myocardial perfusion defects and may differentiate ischemic and infarcted myocardium.
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- 2014
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44. Feasibility of dynamic CT-based adenosine stress myocardial perfusion imaging to detect and differentiate ischemic and infarcted myocardium in an large experimental porcine animal model
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Fabian Bamberg, Ullrich Ebersberger, Daniel Theisen, Roy P. Marcus, Christian Kupatt, Kristof Hildebrandt, Torleif A. Sandner, Florian Schwarz, Christopher L. Schlett, Rabea Hinkel, Elisabeth Baloch, Konstantin Nikolaou, Holger Hetterich, Maximilian F. Reiser, and Udo Hoffmann
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medicine.medical_specialty ,Adenosine ,Time Factors ,Swine ,Myocardial Infarction ,Myocardial Ischemia ,Ischemia ,Infarction ,Perfusion scanning ,Blood volume ,Coronary Angiography ,Diagnosis, Differential ,Myocardial perfusion imaging ,Predictive Value of Tests ,Coronary Circulation ,Internal medicine ,Animals ,Medicine ,Radiology, Nuclear Medicine and imaging ,cardiovascular diseases ,Cardiac imaging ,medicine.diagnostic_test ,business.industry ,Myocardial Perfusion Imaging ,Reproducibility of Results ,Blood flow ,medicine.disease ,Disease Models, Animal ,Regional Blood Flow ,Cardiology ,Feasibility Studies ,Tomography, X-Ray Computed ,Cardiology and Cardiovascular Medicine ,business ,Perfusion ,Blood Flow Velocity - Abstract
The purpose of the study is feasibility of dynamic CT perfusion imaging to detect and differentiate ischemic and infarcted myocardium in a large porcine model. 12 Country pigs completed either implantation of a 75 % luminal coronary stenosis in the left anterior descending coronary artery simulating ischemia or balloon-occlusion inducing infarction. Dynamic CT-perfusion imaging (100 kV, 300 mAs), fluorescent microspheres, and histopathology were performed in all models. CT based myocardial blood flow (MBFCT), blood volume (MBVCT) and transit constant (Ktrans), as well as microsphere’s based myocardial blood flow (MBFMic) were derived for each myocardial segment. According to histopathology or microsphere measurements, 20 myocardial segments were classified as infarcted and 23 were ischemic (12 and 14 %, respectively). Across all perfusion states, MBFCT strongly predicted MBFMic (β 0.88 ± 0.12, p
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- 2014
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45. Gross-total resection outcomes in an elderly population with glioblastoma: a SEER-based analysis
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Abraham Noorbakhsh, Logan P. Marcus, Brandon A. McCutcheon, Craig S Schallhorn, Bob S. Carter, Jessica A. Tang, Mark A. Talamini, Clark C. Chen, David C. Chang, and David D. Gonda
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Oncology ,medicine.medical_specialty ,education.field_of_study ,Proportional hazards model ,business.industry ,Population ,medicine.disease ,Gross Total Resection ,Surgery ,Patient age ,Internal medicine ,Elderly population ,Epidemiology ,medicine ,education ,business ,Survival rate ,Glioblastoma - Abstract
Object There is limited information on the relationship between patient age and the clinical benefit of resection in patients with glioblastoma. The purpose of this study was to use a population-based database to determine whether patient age influences the frequency that gross-total resection (GTR) is performed, and also whether GTR is associated with survival difference in different age groups. Methods The authors identified 20,705 adult patients with glioblastoma in the Surveillance, Epidemiology, and End Results (SEER) registry (1998–2009). Surgical practice patterns were defined by the categories of no surgery, subtotal resection (STR), and GTR. Kaplan-Meier and multivariate Cox regression analyses were used to assess the pattern of surgical practice and overall survival. Results The frequency that GTR was achieved in patients with glioblastoma decreased in a stepwise manner as a function of patient age (from 36% [age 18–44 years] to 24% [age ≥ 75]; p < 0.001). For all age groups, glioblastoma patients who were selected for and underwent GTR showed a 2- to 3-month improvement in overall survival (p < 0.001) relative to those who underwent STR. These trends remained true after a multivariate analysis that incorporated variables including ethnicity, sex, year of diagnosis, tumor size, tumor location, and radiotherapy status. Conclusions Gross-total resection is associated with improved overall survival, even in elderly patients with glioblastoma. As such, surgical decisions should be individually tailored to the patient rather than an adherence to age as the sole clinical determinant.
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- 2014
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46. Myocardial CT Perfusion Imaging in a Large Animal Model
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Verena S. Hoffmann, Kristof Hildebrandt, Bernd J. Wintersperger, Rabea Hinkel, Maximilian F. Reiser, Torleif A. Sandner, Roy P. Marcus, Florian Schwarz, Konstantin Nikolaou, Elisabeth Baloch, Daniel Theisen, Fabian Bamberg, and Christian Kupatt
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medicine.diagnostic_test ,business.industry ,Balloon catheter ,Perfusion scanning ,Blood flow ,medicine.disease ,Myocardial perfusion imaging ,Stenosis ,Radiology Nuclear Medicine and imaging ,Hounsfield scale ,medicine ,Radiology, Nuclear Medicine and imaging ,business ,Nuclear medicine ,Cardiology and Cardiovascular Medicine ,Perfusion ,Computed tomography angiography - Abstract
Objectives This study sought to compare dynamic versus single-phase high-pitch computed tomography (CT) acquisitions for the assessment of myocardial perfusion in a porcine model with adjustable degrees of coronary stenosis. Background The incremental value of the 2 different approaches to CT-based myocardial perfusion imaging remains unclear. Methods Country pigs received stent implantation in the left anterior descending coronary artery, in which an adjustable narrowing (50% and 75% stenoses) was created using a balloon catheter. All animals underwent CT-based rest and adenosine-stress myocardial perfusion imaging using dynamic and single-phase high-pitch acquisitions at both degrees of stenosis. Fluorescent microspheres served as a reference standard for myocardial blood flow. Segmental CT-based myocardial blood flow (MBFCT) was derived from dynamic acquisitions. Segmental single-phase enhancement (SPE) was recorded from high-pitch, single-phase examinations. MBFCT and SPE were compared between post-stenotic and reference segments, and receiver-operating characteristic curve analysis was performed. Results Among 6 animals (28 ± 2 kg), there were significant differences of MBFCT and SPE between post-stenotic and reference segments for all acquisitions at 75% stenosis. By contrast, although for 50% stenosis at rest, MBFCT was lower in post-stenotic than in reference segments (0.65 ± 0.10 ml/g/min vs. 0.75 ± 0.16 ml/g/min, p Conclusions At higher degrees of coronary stenosis, both MBFCT and SPE permit an accurate prediction of segmental myocardial hypoperfusion. However, accuracy of MBFCT is higher than that of SPE at 50% stenosis and can be increased by adenosine stress at both degrees of stenosis.
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- 2013
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47. Dynamic CT myocardial perfusion imaging: performance of 3D semi-automated evaluation software
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U. Joseph Schoepf, Konstantin Nikolaou, Yining Wang, P Blanke, Lucas L. Geyer, Gladys G. Lo, Christian Canstein, Young Jun Cho, Andrew D. McQuiston, Ullrich Ebersberger, Michael Scheuering, Ellen Hoffmann, Roy P. Marcus, Fabian Bamberg, and J. Cranston Gray
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Male ,medicine.medical_specialty ,Blood volume ,Perfusion scanning ,Coronary Artery Disease ,Coronary Angiography ,Myocardial perfusion imaging ,Imaging, Three-Dimensional ,Software ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Retrospective Studies ,Neuroradiology ,Tomography, Emission-Computed, Single-Photon ,medicine.diagnostic_test ,business.industry ,Myocardial Perfusion Imaging ,Reproducibility of Results ,General Medicine ,Blood flow ,Middle Aged ,Female ,Radiology ,Tomography ,Tomography, X-Ray Computed ,Nuclear medicine ,business ,Perfusion - Abstract
To evaluate the performance of three-dimensional semi-automated evaluation software for the assessment of myocardial blood flow (MBF) and blood volume (MBV) at dynamic myocardial perfusion computed tomography (CT).Volume-based software relying on marginal space learning and probabilistic boosting tree-based contour fitting was applied to CT myocardial perfusion imaging data of 37 subjects. In addition, all image data were analysed manually and both approaches were compared with SPECT findings. Study endpoints included time of analysis and conventional measures of diagnostic accuracy.Of 592 analysable segments, 42 showed perfusion defects on SPECT. Average analysis times for the manual and software-based approaches were 49.1 ± 11.2 and 16.5 ± 3.7 min respectively (P 0.01). There was strong agreement between the two measures of interest (MBF, ICC = 0.91, and MBV, ICC = 0.88, both P 0.01) and no significant difference in MBF/MBV with respect to diagnostic accuracy between the two approaches for both MBF and MBV for manual versus software-based approach; respectively; all comparisons P 0.05.Three-dimensional semi-automated evaluation of dynamic myocardial perfusion CT data provides similar measures and diagnostic accuracy to manual evaluation, albeit with substantially reduced analysis times. This capability may aid the integration of this test into clinical workflows.• Myocardial perfusion CT is attractive for comprehensive coronary heart disease assessment. • Traditional image analysis methods are cumbersome and time-consuming. • Automated 3D perfusion software shortens analysis times. • Automated 3D perfusion software increases standardisation of myocardial perfusion CT. • Automated, standardised analysis fosters myocardial perfusion CT integration into clinical practice.
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- 2013
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48. Sex, Color, and Geography: Racialized Relations in Brazil and Its Predicaments
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Alan P. Marcus
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Race (biology) ,Anthropology ,parasitic diseases ,Geography, Planning and Development ,Gender studies ,Sociology ,Earth-Surface Processes - Abstract
Sex and race have significantly affected the trajectories of Brazil's historical geographies and its contemporary racialized relations. Interpretations of gender, race, and color in Brazil have pro...
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- 2013
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49. Brain penetrant liver X receptor (LXR) modulators based on a 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole core
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Jing Zhou, Suresh B. Singh, Colin M. Tice, Rebecca Van Orden, Guozhou Chen, Geeta Kandpal, Shi Meng, Cheng-Guo Dong, Yuri Bukhtiyarov, Paul B. Noto, Stephen D. Lotesta, Wei Zhao, Lamont Howard, Katerina Leftheris, Andrew P. Marcus, Kristi Fan, Andrew W. Hardy, Deepak S. Lala, Paula Krosky, Linghang Zhuang, Brian M. McKeever, Gerard McGeehan, Kerri Lipinski, Ya-Jun Zheng, Joan Guo, Yi Zhao, Richard Gregg, David A. Claremon, and Zhongren Wu
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0301 basic medicine ,Male ,medicine.medical_specialty ,Amyloid beta ,Clinical Biochemistry ,Pharmaceutical Science ,Pyrazole ,Pharmacology ,digestive system ,Biochemistry ,DNA-binding protein ,Rats, Sprague-Dawley ,03 medical and health sciences ,chemistry.chemical_compound ,Structure-Activity Relationship ,0302 clinical medicine ,Downregulation and upregulation ,Oral administration ,Internal medicine ,Drug Discovery ,polycyclic compounds ,medicine ,Animals ,RNA, Messenger ,Liver X receptor ,Molecular Biology ,Liver X Receptors ,biology ,Chemistry ,Organic Chemistry ,Brain ,Rats ,Up-Regulation ,030104 developmental biology ,Endocrinology ,ABCA1 ,biology.protein ,Molecular Medicine ,lipids (amino acids, peptides, and proteins) ,Penetrant (biochemical) ,030217 neurology & neurosurgery ,ATP Binding Cassette Transporter 1 - Abstract
Liver X receptor (LXR) agonists have been reported to lower brain amyloid beta (Aβ) and thus to have potential for the treatment of Alzheimer's disease. Structure and property based design led to the discovery of a series of orally bioavailable, brain penetrant LXR agonists. Oral administration of compound 18 to rats resulted in significant upregulation of the expression of the LXR target gene ABCA1 in brain tissue, but no significant effect on Aβ levels was detected.
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- 2016
50. Imaging Evaluation of Acute Chest Pain
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Jr Jw Nance, Fabian Bamberg, Konstantin Nikolaou, Roy P. Marcus, Udo Hoffmann, Uwe Joseph Schoepf, Thorsten R. C. Johnson, M. F. Reiser, and Christopher L. Schlett
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Pulmonary and Respiratory Medicine ,Chest Pain ,medicine.medical_specialty ,Cost effectiveness ,Cost-Benefit Analysis ,Coronary Angiography ,Chest pain ,Myocardial perfusion imaging ,Cardiac magnetic resonance imaging ,medicine ,Acute chest pain ,Humans ,Radiology, Nuclear Medicine and imaging ,Evidence-Based Medicine ,medicine.diagnostic_test ,business.industry ,Myocardial Perfusion Imaging ,Magnetic resonance imaging ,Emergency department ,Evidence-based medicine ,Magnetic Resonance Imaging ,Acute Disease ,Radiology ,medicine.symptom ,Tomography, X-Ray Computed ,business - Abstract
Given the often inconclusive initial evaluation of patients presenting with acute chest pain in the Emergency Department, advanced imaging techniques have been evaluated in the quest for improving the current standard of care. In this article, we systematically compare and evaluate the available evidence and cost-effectiveness of radionucleotide myocardial perfusion imaging, cardiac computed tomography angiography, and cardiac magnetic resonance imaging using data from PubMed and EMBASE through January 2012. The obtained data were summarized and categorized according to the reached level of evidence and its impact on the decision-making process.
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- 2012
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