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Lookup NU author(s): Professor Ian McKeith,
Professor John O'Brien
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Establishing an early, accurate diagnosis is fundamental for appropriate clinical management of patients with movement disorders or dementia. Ioflupane I-123 Injection (DaTscan, I-123-ioflupane) is an important adjunct to support the clinical diagnosis. Understanding individual-reader diagnostic performance of I-123-ioflupane in a variety of clinical scenarios is essential. Methods: Sensitivity, specificity, interreader, and intrareader data from 5 multicenter clinical studies were reviewed. The different study designs offered an assortment of variables to assess the effects on the diagnostic performance of I-123-ioflupane: on-site versus 3-5 blinded image readers, number of image evaluations, early/uncertain versus late/confirmed clinical diagnosis as reference standard, and subjects with movement disorders versus dementia. Results: Eight hundred eighteen subjects had individual-reader efficacy data available for analysis. In general, sensitivity and specificity were high and comparable between on-site versus blinded independent readers. In subjects with dementia, when the clinical diagnosis was made at month 12 versus baseline, specificity improved from 77.4%-91.2% to 81.6%-95.0%. In subjects with movement disorders, this effect was observed to an even greater extent, when diagnostic performance riding month-18 diagnosis as a reference standard (sensitivity, 67.0%-73.7%; specificity, 75.0%-83.3%) was compared versus month-36 diagnosis (77.5%-80.3% and 90.3%-96.8%, respectively). Diagnostic performance was similar in subjects with dementia (74.4%-89.9% and 77.4%-95.0%, respectively) and subjects with movement disorders (67.0%-97.9% and 71.4%-98.4%, respectively). In most of the comparisons, between-reader agreement was very good (almost perfect), with K ranging from 0.81 to 1.00. Within-reader agreement, measured in 1 study, was 100% for 3 blinded readers. Conclusion: Individual-reader diagnostic performance, as assessed by measuring sensitivity and specificity of I-123-ioflupane to detect the presence or absence of striatal dopaminergic deficit, using the clinical diagnosis as a reference standard, was high in subjects with either movement disorders or dementia and was similar in on-site readers versus blinded analyses. Between- and within-reader agreements were very good (almost perfect). Longer follow-up between imaging and clinical diagnosis improved the diagnostic accuracy, most likely due to improvement in the clinical diagnosis reference standard, rather than changes in reader accuracy.
Author(s): Seibyl JP, Kupsch A, Booij J, Grosset DG, Costa DC, Hauser RA, Darcourt J, Bajaj N, Walker Z, Marek K, McKeith I, O'Brien JT, Tatsch K, Tolosa E, Dierckx RA, Grachev ID
Publication type: Article
Publication status: Published
Journal: Journal of Nuclear Medicine
Print publication date: 01/08/2014
Online publication date: 12/06/2014
ISSN (print): 0161-5505
ISSN (electronic): 1535-5667
Publisher: Society of Nuclear Medicine
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