Individual-reader diagnostic performance and between-reader agreement in assessment of subjects with Parkinsonian syndrome or dementia using 123I-ioflupane injection (DaTscan) imaging.

Abstract

UNLABELLED:

Establishing an early, accurate diagnosis is fundamental for appropriate clinical management of patients with movement disorders or dementia. Ioflupane (123)I Injection (DaTscan, (123)I-ioflupane) is an important adjunct to support the clinical diagnosis. Understanding individual-reader diagnostic performance of (123)I-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 (123)I-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 using 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 κ 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 (123)I-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.

• Authors: John P Seibyl, Andreas Kupsch, Jan Booij, Donald G Grosset, Durval C Costa, Robert A Hauser, Jacques Darcourt, Nin Bajaj, Zuzana Walker, Kenneth Marek, Ian McKeith, John T O'Brien, Klaus Tatsch, Eduardo Tolosa, Rudi A Dierckx, Igor D Grachev
• Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med) Vol. 55 Issue 8 Pg. 1288-96 (Aug 2014) ISSN: 1535-5667 [Electronic] United States
• PMID: 24925885 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Chemical References

• Nortropanes
• ioflupane

Topics

• Adult
• Aged
• Aged, 80 and over
• Clinical Trials as Topic
• Dementia (diagnostic imaging)
• Female
• Follow-Up Studies
• Humans
• Injections
• Male
• Middle Aged
• Multicenter Studies as Topic
• Nortropanes (administration & dosage)
• Observer Variation
• Parkinsonian Disorders (diagnostic imaging)
• Sensitivity and Specificity
• Time Factors
• Tomography, Emission-Computed, Single-Photon
• Young Adult