Research Topics
| N A ObuchowskiSummaryAffiliation: Cleveland Clinic Foundation Country: USA Publications
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Detail Information
Publications
Screening with multisection CT: unmasking the benefitNancy A Obuchowski
Radiology 237:401-3. 2005- Estimating sample size for a randomized clinical trial of lung cancer screeningNancy A Obuchowski
Department of Quantitative Health Sciences Wb4, Division of Radiology, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
Contemp Clin Trials 29:466-77. 2008.... - Multireader, multicase receiver operating characteristic analysis: an empirical comparison of five methodsNancy A Obuchowski
Departments of Biostatistics and Epidemiology, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
Acad Radiol 11:980-95. 2004..The objective of this article is to increase awareness of these methods and determine if their results are concordant for published datasets... - How many observers are needed in clinical studies of medical imaging?Nancy A Obuchowski
Department of Biostatistics and Epidemiology, Desk Wb4, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
AJR Am J Roentgenol 182:867-9. 2004 - Special Topics III: biasNancy A Obuchowski
Departments of Biostatistics and Epidemiology and Radiology Wb4, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
Radiology 229:617-21. 2003..Potential implications of various biases are discussed, and practical approaches to eliminating or minimizing them are presented... - Receiver operating characteristic curves and their use in radiologyNancy A Obuchowski
Department of Biostatistics and Epidemiology Wb4, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
Radiology 229:3-8. 2003..Two examples of ROC curve application in radiologic research are presented... - ROC curves in clinical chemistry: uses, misuses, and possible solutionsNancy A Obuchowski
Department of Biostatistics, Division of Radiology Wb4, The Cleveland Clinic Foundation, Cleveland, OH 44195 5196, USA
Clin Chem 50:1118-25. 2004..Our aims were to observe how the accuracy of clinical laboratory diagnostic tests is assessed, compared, and reported in the literature; to identify common problems with the use of ROC curves; and to offer some possible solutions... - Estimating and comparing diagnostic tests' accuracy when the gold standard is not binaryNancy A Obuchowski
Department of Quantitative Health Sciences Wb4, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
Acad Radiol 12:1198-204. 2005..The objective of this article is to describe nonparametric estimators of diagnostic test accuracy when the gold standard is continuous, ordinal, and nominal scale... - Total body screening: predicting actionable findingsNancy Obuchowski
Division of Radiology, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
Acad Radiol 13:480-5. 2006..Even the appropriate target for screening has not been addressed. In this study, we determined the variables from a subject's demographic and medical and family history that are predictive of actionable findings on total body screening... 
What's the control in studies measuring the effect of computer-aided detection (CAD) on observer performance?Nancy A Obuchowski
Quantitative Health Sciences, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA
Acad Radiol 17:761-7. 2010..The crossover design is considered the most valid. The sequential design takes less time and is less expensive but may be biased. We conducted a study to investigate the differences between these two designs...- Assessing physicians' accuracy in diagnosing paediatric patients with acute abdominal pain: measuring accuracy for multiple diseasesN A Obuchowski
Department of Biostatistics and Epidemiology Wb4, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195 5196, USA
Stat Med 20:3261-78. 2001..The new data collection format and summary measure were used in a paediatric acute abdominal pain study; data from this study are used to illustrate the methods... - Assessment of the efficacy of noninvasive screening for patients with asymptomatic neck bruitsN A Obuchowski
Department of Biostatistics and Epidemiology, Cleveland Clinic Foundation, Ohio 44195, USA
Stroke 28:1330-9. 1997..The purpose of this study was to evaluate the effectiveness of various test strategies for screening and diagnosing carotid artery disease... - Sample size calculations in studies of test accuracyN A Obuchowski
Department of Biostatistics and Epidemiology, Cleveland Clinic Foundation, OH 44195 5196, USA
Stat Methods Med Res 7:371-92. 1998..Four real examples illustrate the concepts involved in sample size determination. Lastly, various study design issues are discussed, such as sampling methods, choices in format for the test results, and the issue of replicated readings... - On the comparison of correlated proportions for clustered dataN A Obuchowski
Department of Biostatistics and Epidemiology, Cleveland Clinic Foundation, Ohio 44195 5196, USA
Stat Med 17:1495-507. 1998..The proposed method is a good alternative to Eliasziw and Donner's test when, in practice, little is known about the correlation pattern of the data... - Can electronic medical images replace hard-copy film? Defining and testing the equivalence of diagnostic testsN A Obuchowski
Department of Biostatistics and Epidemiology Wb4 and the Division of Radiology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio 44195 5196, USA
Stat Med 20:2845-63. 2001..Data from a mammography screening study is used to illustrate the proposed methods and compare them with results from more conventional methods of assessing equivalence and inter-procedure agreement... - Quantitative detection of outlet strut separations in Björk-Shiley convexo-concave mitral valvesK A Powell
Department of Biomedical Engineering, Cleveland Clinic Foundation, OH 44195, USA
Circulation 94:3251-6. 1996..The goal of the present study was to develop an objective postprocessing technique to evaluate outlet strut leg integrity quantitatively in these cineradiographic images... - Cholecystokinin-stimulated peak lipase concentration in duodenal drainage fluid: a new pancreatic function testDarwin L Conwell
The Pancreas Clinic, Section of Endoscopy and Pancreaticobiliary Diseases, Cleveland Clinic Foundation, Ohio, USA
Am J Gastroenterol 97:1392-7. 2002..Measurement of enzyme concentration instead of output could lead to the development of an endoscopic or through-the-scope screening method for assessing patients with suspected chronic pancreatitis or chronic abdominal pain... - The "differential diagnosis" for multiple diseases: comparison with the binary-truth state experiment in two empirical studiesN A Obuchowski
Department of Biostatistics and Epidemiology, The Cleveland Clinic Foundation, OH 44195, USA
Acad Radiol 8:947-54. 2001..The differential diagnosis format is useful for estimating accuracy when there are multiple possible diagnoses... - Creating an international comprehensive web-based curriculum in pediatric radiologyJanet R Reid
The Children s Hospital at the Cleveland Clinic, 9500 Euclid Avenue, Hb6, Cleveland, OH 44195, USA
AJR Am J Roentgenol 182:797-801. 2004.... - An endoscopic pancreatic function test with cholecystokinin-octapeptide for the diagnosis of chronic pancreatitisDarwin L Conwell
Department of Gastroenterology and Hepatology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
Clin Gastroenterol Hepatol 1:189-94. 2003..We have developed a function test that can be modified to a purely endoscopic collection method (ePFT). The aim of this study was to compare the endoscopic and traditional Dreiling tube collection methods... - Probability of reduced renal function after contrast-enhanced CT: a model based on serum creatinine level, patient age, and estimated glomerular filtration rateBrian R Herts
Imaging Institute, Cleveland Clinic, 9500 Euclid Ave, Desk Hb6, Cleveland, OH 44195, USA
AJR Am J Roentgenol 193:494-500. 2009.... - Whole-body CT screening for cancer and coronary disease: does it pass the test?Michael T Modic
Division of Radiology, The Cleveland Clinic Foundation, OH 44195, USA
Cleve Clin J Med 71:47-56. 2004.... - Vertebral augmentation and the limits of interpreting complications reported in the food and drug administration manufacturer and user facility device experience databaseIsador H Lieberman
Department of Orthopaedic Surgery, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
J Vasc Interv Radiol 15:1193-6. 2004 - Lung cancer screening: is it time for a change in policy?Peter Mazzone
Department of Pulmonary, Allergy, and Critical Care Medicine, Cleveland Clinic, Cleveland, OH 44195, USA
Cleve Clin J Med 74:441-8. 2007..These questions warrant further study prior to accepting CT screening as the standard of care. Hopefully, much of this knowledge will be gained when the results of ongoing controlled studies are available... - Do segmented reconstruction algorithms for cardiac multi-slice computed tomography improve image quality?Sandra S Halliburton
Section of Cardiovascular Imaging, Division of Radiology, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
Herz 28:20-31. 2003..To evaluate segmented reconstruction algorithms for spiral multi-slice computed tomography (MSCT) that use data from two cardiac cycles to improve temporal resolution (tau) for imaging of the heart... - Evaluation of left ventricular dysfunction using multiphasic reconstructions of coronary multi-slice computed tomography data in patients with chronic ischemic heart disease: validation against cine magnetic resonance imagingSandra S Halliburton
Section of Cardiovascular Imaging, Division of Radiology Cleveland Clinic Foundation, Cleveland, OH 44195, USA
Int J Cardiovasc Imaging 19:73-83. 2003..The purpose of this work was to determine if multiphasic reconstructions of the same data used for the assessment of CAD could also be used for global functional evaluation of the left ventricle (LV)... - Automatic segmentation of mammographic densityR Sivaramakrishna
Department of Biomedical Engineering, Lerner Research Institute, Cleveland, OH, USA
Acad Radiol 8:250-6. 2001..This algorithm could be useful in providing clinically accurate estimates of breast density... - An endoscopic pancreatic function test with synthetic porcine secretin for the evaluation of chronic abdominal pain and suspected chronic pancreatitisDarwin L Conwell
The Pancreas Clinic, Department of Gastroenterology, Section, Cleveland Clinic Foundation, Cleveland, Ohio, USA
Gastrointest Endosc 57:37-40. 2003..This simple, practical endoscopic test can be performed during upper endoscopy and may decrease the need for invasive procedures in patients with abdominal pain and normal radiographic imaging studies... - Effects of diagnostic information, per se, on patient outcomes in acute radiculopathy and low back painL M Ash
Division of Radiology, Cleveland Clinic Foundation, Cleveland, Ohio, USA
AJNR Am J Neuroradiol 29:1098-103. 2008..If this rationale is valid, one would expect to see a measurable effect from diagnostic information, per se... - Does the presence of focal normal marrow fat signal within a tumor on MRI exclude malignancy? An analysis of 184 histologically proven tumors of the pelvic and appendicular skeletonC S Simpfendorfer
Department of Radiology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
Skeletal Radiol 37:797-804. 2008..The aim of this study was to determine if the presence of focal normal bone marrow fat signal within a tumor on magnetic resonance imaging excludes malignancy... - Spiral CT scanning technique in the detection of aspiration of LEGO foreign bodiesK E Applegate
Department of Radiology, Cleveland Clinic Foundation, 11 106 Euclid Avenue, Cleveland, OH 44196, USA
Pediatr Radiol 31:836-40. 2001..Materials and.. - Noninvasive assessment of cardiac mechanics and clinical outcome after partial left ventriculectomyRandolph M Setser
Department of Radiology, The Cleveland Clinic Foundation, OH, USA
Ann Thorac Surg 76:1576-85; discussion 1585-6. 2003..MRI with tissue tagging is useful for assessing the efficacy of surgical therapies for congestive heart failure... - Analysis of changes in attenuation of proven renal cysts on different scanning phases of triphasic MDCTEugene P Chung
Department of Radiology - HB6, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
AJR Am J Roentgenol 182:405-10. 2004..255), or percentage of the lesion that was exophytic (p > 0.124). CONCLUSION: The attenuation coefficient of a cystic renal lesion increased by no more than 10 H among the unenhanced, corticomedullary, and parenchymal phase scans... - Enhancement characteristics of papillary renal neoplasms revealed on triphasic helical CT of the kidneysBrian R Herts
Department of Radiology-H66, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
AJR Am J Roentgenol 178:367-72. 2002..A low tumor-to-aorta enhancement ratio or tumor-to-normal renal parenchyma enhancement ratio is more likely to indicate papillary renal cell carcinoma... - The predictive value of helical computed tomography for collecting-system entry during nephron-sparing surgeryIthaar H Derweesh
Section of Abdominal Imaging, Department of Diagnostic Radiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
BJU Int 98:963-8. 2006..4%, specificity 74.7%, P = 0.005). There were no significant associations with side or type of surgery (P > 0.83). CONCLUSION: Helical CT is a reliable predictor of calyceal entry at surgery... - Computer-aided detection of colorectal polyps: can it improve sensitivity of less-experienced readers? Preliminary findingsMark E Baker
Department of Radiology, The Cleveland Clinic Foundation, 9500 Euclid Ave, Hb6, Cleveland, OH 44195, USA
Radiology 245:140-9. 2007.... - Total-body screening: preliminary results of a pilot randomized controlled trialNancy A Obuchowski
Division of Radiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
J Am Coll Radiol 4:604-11. 2007..The authors performed a pilot randomized controlled trial of total-body screening to assess the feasibility of a full-scale study... - The effect of misclassification in screening trials: a simulation studyNancy A Obuchowski
Department of Quantitative Health Sciences, Cleveland Clinic, OH 44195, USA
Contemp Clin Trials 29:125-35. 2008..Misclassification of study endpoints in randomized clinical trials of screening tests has been well documented, yet its effect on study power, type I error rate, and risk ratio estimate have not been studied in depth... - Identifying outpatients with renal insufficiency before contrast-enhanced CT by using estimated glomerular filtration rates versus serum creatinine levelsBrian R Herts
Division of Radiology, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
Radiology 248:106-13. 2008.... - Statistics and methodologyNancy A Obuchowski
Department of Quantitative Health Sciences, Lerner Research Institute and Imaging Institute, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
Skeletal Radiol 37:393-6. 2008 - New methodological tools for multiple-reader ROC studiesNancy A Obuchowski
Radiology 243:10-2. 2007 - A comparison of the Dorfman-Berbaum-Metz and Obuchowski-Rockette methods for receiver operating characteristic (ROC) dataStephen L Hillis
Center for Research in the Implementation of Innovative Strategies in Practice, Iowa City VA Medical Center, Iowa City, IA, USA
Stat Med 24:1579-607. 2005..The methods are compared using data from a factorial study with two modalities, five readers, and 114 patients... - Determining sample size for ROC studies: what is reasonable for the expected difference in tests' ROC areas?Nancy A Obuchowski
Acad Radiol 10:1327-8. 2003 - Acute low back pain and radiculopathy: MR imaging findings and their prognostic role and effect on outcomeMichael T Modic
Division of Radiology, Spine Center, Cleveland Clinic Foundation, Cleveland, Ohio, 44195, USA
Radiology 237:597-604. 2005..To prospectively determine in patients with acute low back pain (LBP) or radiculopathy, the magnetic resonance (MR) imaging findings, prognostic role of these findings, and effect of diagnostic information on outcome... - An ROC-type measure of diagnostic accuracy when the gold standard is continuous-scaleNancy A Obuchowski
Department of Quantitative Health Sciences Wb4, and the Division of Radiology, The Cleveland Clinic Foundation, 9500 Euclid Avenue, OH 44195 5196, USA
Stat Med 25:481-93. 2006..e. CI coverage, type I error rate, power) of the proposed methods with several alternatives. An example is presented where the accuracies of two quick blood tests for measuring serum iron concentrations are estimated and compared... - Confidence bounds when the estimated ROC area is 1.01Nancy A Obuchowski
Department of Biostatistics and Epidemiology The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland OH, 44195, USA
Acad Radiol 9:526-30. 2002..The tables provided in this article are useful for interpreting studies with estimated ROC areas of 1.0... - Clinical evaluation of diagnostic testsSusan Weinstein
Department of Radiology, University of Pennsylvania Medical Center, Medical Center, Philadelphia, PA 19104, USA
AJR Am J Roentgenol 184:14-9. 2005 - Calcium scoring: criteria for evaluating its effectivenessNancy A Obuchowski
Department of Biostatistics and Epidemiology, Cleveland Clinic Foundation, Cleveland, OH, USA
Semin Ultrasound CT MR 24:39-44. 2003..We discuss how these criteria can be used to estimate NNS and NSH. Although this work focuses on coronary calcification screening, reference is made as well to other areas, such as lung and colon cancer screening... - One less bias to worry aboutNancy A Obuchowski
Radiology 232:302. 2004 - ROC analysisNancy A Obuchowski
Department of Biostatistics and Epidemiology, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH, USA
AJR Am J Roentgenol 184:364-72. 2005 - Assessment of suspected breast cancer by MRI: a prospective clinical trial using a combined kinetic and morphologic analysisJonathan I Wiener
Department of Radiology, Boca Raton Community Hospital, 800 Meadows Rd, Boca Raton, FL 33486, USA
AJR Am J Roentgenol 184:878-86. 2005.... - Multivariate statistical methodsNancy A Obuchowski
Department of Quantitative Health Sciences, Rm. Wb4, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
AJR Am J Roentgenol 185:299-309. 2005 - Incidence of advanced symptomatic disease as primary endpoint in screening and prevention trialsNancy A Obuchowski
Department of Quantitative Health Sciences, Wb4, The Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
AJR Am J Roentgenol 189:19-23. 2007..This endpoint is sensitive to the benefit of screening, correlates with patients' quality of life and societal costs, and can dramatically reduce the sample size and follow-up requirements of RCTs... - Colonic abnormalities on CT in adult hospitalized patients with Clostridium difficile colitis: prevalence and significance of findingsLorraine Ash
Division of Radiology/Hb 6, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, USA
AJR Am J Roentgenol 186:1393-400. 2006..Positive scans were more likely in patients with leukocytosis, abdominal pain, and fever. Specific CT findings did not correlate with clinical parameters and could not predict surgical treatment...