Utility of 123I-FP-CIT SPECT for dementia diagnoses and therapeutic strategies in elderly patients

Abstract

Objectives: Evaluation of the influence of single photon emission computed tomography (SPECT) of the dopamine transporter (123I-FP-CIT) on diagnosis and treatment strategies in elderly patients with mild dementia.

Design: Retrospective study.

Setting: Geriatrics memory clinic.

Participants: Consecutive ambulatory patients who had 123I-FP-CIT SPECT for a suspicion of DLB.

Measurements: Clinical diagnoses before SPECT were compared with imaging results.

Results: 46 patients were included. Pre imaging clinical hypotheses were probable DLB in 14, possible DLB in 21 and alternate diagnoses in 11. Rates of abnormal imaging in these groups were respectively 71%, 43% and 18%. Overall, diagnoses were revised in 37% of the cases. Four patients with probable DLB had normal imaging. Their number of core criteria did not differ from the remainder (2.75 ± 0.5 vs. 2.1 ± 0.6), but hallucinations in 2 patients were not well formed and detailed as usual in DLB. Among 38 patients free of antipsychotics, rates of abnormal scans were 36% in patients with questionable parkinsonism, 57% in definite parkinsonism, 67% in patients with no parkinsonism. Among 9 patients on Levodopa, 6 had normal scans and Levodopa was stopped.

Conclusion: We show a significant impact of 123I-FP-CIT SPECT on diagnoses, even in cases of definite parkinsonism or probable DLB. In the latter, scarcity of hallucinations, especially if there are not well formed and detailed, should prompt 123I-FP-CIT SPECT.