Combined 123I-FP-CIT and 123I-IBZM SPECT for the diagnosis of parkinsonian syndromes: study on 72 patients

72 consecutive patients with suspected parkinsonian syndromes (PS) were studied by dopamine transporter (DAT) and D2 receptor SPECT in order to evaluate the accuracy of combined SPECT imaging. In the follow-up, the patients were diagnosed as having Parkinson's disease (PD, n = 25), dementia with Lewy bodies (DLB, n = 6), multiple system atrophy (MSA, n = 13), progressive supranuclear palsy (PSP, n = 8), corticobasal degeneration (CBD, n = 9), and essential tremor (ET, n = 11). Using the iteratively estimated optimal cutoffs, DAT was reduced in 57/61 PS patients, whereas all ET patients were identified as "normal". Reduced D2 receptor binding had 7/13 patients with MSA, 6/8 patients with PSP, 2/9 patients with CBD and no ET, PD or DLB patients. FP-CIT SPECT allows an accurate detection of nigrostriatal affection in neurodegenerative PS. IBZM SPECT is useful to approve the diagnosis of PSP and MSA although a normal finding cannot exclude an atypical PS. IBZM SPECT seems to be of restricted value in CBD.