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A comparison of Tc-99m-exametazime and I-123-FP-CIT SPECT imaging in the differential diagnosis of Alzheimer's disease and dementia with Lewy bodies

Lookup NU author(s): Dr Sean Colloby, Dr Michael FirbankORCiD, Dr Sanjeet Pakrasi, Dr James LloydORCiD, Dr Ian Driver, Professor Ian McKeith, Professor David Williams, Professor John O'Brien



Background: The aim of this study is to investigate the diagnostic value of perfusion Tc-99m-exametazime single photon emission computed tomography (SPECT) in the diagnosis of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) in comparison with dopaminergic I-123-2 beta-carbomethoxy-3 beta-(4-iodophenyl)-n-(3-fluoropropyl) nortropane (FP-CIT) SPECT imaging. Methods: Subjects underwent Tc-99m-exametazime scanning (39 controls, 36 AD, 30 DLB) and I-123-FP-CIT scanning (33 controls, 33 AD, 28 DLB). For each scan, five raters performed visual assessments blind to clinical diagnosis on selected transverse (99)mTc-exametazime images in standard stereotactic space. Diagnostic accuracy of Tc-99m-exametazime was compared to I-123-FP-CIT results for the clinically relevant subgroups AD and DLB using receiver operating characteristic (ROC) curve analysis. Results: Inter-rater agreement for categorizing uptake was "moderate" (mean kappa = 0.53) for Tc-99m-exametazime and "excellent" (mean kappa = 0.88) for I-123-FP-CIT For AD and DLB, consensus rating matched clinical diagnosis in 56% of cases using Tc-99m-exametazime and 84% using I-123-FP-CIT In distinguishing AD from DLB, ROC analysis revealed superior diagnostic accuracy with I-123- FP-CIT (ROC curve area 0.83, sensitivity 78.6%, specificity 87.9%) compared to occipital Tc-99m-exametazime (ROC curve area 0.64, sensitivity 64.3%, specificity 63.6%) p = 0.03. Conclusion: Diagnostic accuracy was superior with I-123-FP-CIT compared to Tc-99m-exametazime in the differentiation of DLB from AD.

Publication metadata

Author(s): Colloby SJ, Firbank MJ, Pakrasi SE, Lloyd JJ, Driver I, McKeith IG, Williams ED, O'Brien JT

Publication type: Article

Publication status: Published

Journal: International Psychogeriatrics

Year: 2008

Volume: 20

Issue: 6

Pages: 1124-1140

Date deposited: 01/06/2010

ISSN (print): 1041-6102

ISSN (electronic): 1741-203X

Publisher: Cambridge University Press


DOI: 10.1017/S1041610208007709

Notes: Times Cited: 0


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