[۹۹mTc]Tc-TRODAT-۱ scan diagnostic accuracy for differentiation of dementia of Lewy body from Alzheimer’s disease

Introduction: Dopamine transporter (DAT) receptors are reduced in the striatum in dementia of Lewy body (DLB) but normal in Alzheimer’s disease (AD). We assessed the diagnostic accuracy of TRODAT-۱ imaging to differentiate patients with DLB from AD.Methods: Patients with DLB or AD underwent SPECT TRODAT imaging by [۹۹mTc]Tc-TRODAT-۱. Visual interpretation and quantification analyses were done. The activity of the right and left caudate nucleus (CN), putamen (P), striatum (S) as a whole, background (BG), and occipital area (OC) were calculated in addition to the ratio of right and left CN/OC, P/OC, and S/BG. Absolute right and left value difference of the striatum (∆S), putamen (∆P), and caudate (∆CN) to OC or BG were also calculated. The diagnostic accuracy of the visual and quantitative method were compared between patients with AD and LBD. The area under the ROC curve (AUC) was analyzed.Results: Twenty-five patients (۱۵ DLB and ۱۰ AD) were included. Scans were visually interpreted as DLB, AD, and non-diagnostic in ۱۱, ۱۳, and one patients, respectively. Sensitivity, specificity, and accuracy of the scan were ۵۷.۱% (۲۸.۹-۸۲.۳), ۷۰% (۳۴.۸-۹۳.۳), and ۶۲.۵% (۴۰.۶-۸۱.۲), respectively. CN/OC, P/OC, and S/BG in the left, right, and bilaterally were statistically same between two groups. The AUC of ∆CN/OC was ۷۰.۷%.  The optimal cut-off value for ∆CN/BG to diagnose DLB was ۶.۶% with a sensitivity, specificity, and accuracy, of ۸۶.۷%, ۵۰%, and ۷۲.۰%, respectively.Conclusion: The [۹۹mTc]Tc-TRODAT-۱ imaging has limited diagnostic accuracy for discrimination of DLB and AD patients.

Keywords:

Dementia , Lewy body , Alzheimer’s disease , [۹۹mTc]Tc-TRODAT-۱