Identification of patterns of abnormalities seen on DaTscan™ SPECT imaging in patients with non-Parkinson’s movement disorders

Purpose: To identify patterns of abnormalities using DaTscan[TM] single photon emission-computed tomography (SPECT) imaging of patients with non-Parkinson's movement disorders. Materials and methods: A single institution retrospective evaluation was performed of consecutive patients who underwent DaTscan SPECT imaging for Parkinson's-like movement disorders, excluding those who had scan findings consistent with Parkinson's disease. Demographic and clinical data were collected for all patients. A single experienced reader graded the degree of decreased dopamine transporter activity using a semi-quantitative visual score. Additional quantitative analysis was utilized to generate z-scores in 101/104 patients. Data were analyzed to establish patterns and frequency of abnormalities on DaTscan. Correlation between quantitative and semi-quantitative visual scores was also performed. Results: A total of 104 patients were included, of which 77 patients (74%) had abnormal findings on semi-quantitative visual assessment of the DaTscan images and 27 patients (26%) had normal findings. Of the abnormalities, the majority were either mild or moderate decrease in tracer accumulation, in one or both putamina. The most common site of abnormality was the left posterior putamen followed by the right posterior putamen. Quantitative z-score analysis revealed that 14% of the patients exhibited an abnormality, while 86% had normal z-scores. Conclusion: Semi-quantitative visual DaTscan analysis of patients with non-Parkinson's movement disorders most commonly reveals mild to moderate decrease in dopamine transporter activity, primarily involving the posterior aspect of one of the putamina. Keywords: DaTscan[TM], tremor, movement disorders, dopamine transporter, [.sup.123]I-ioflupane