Comparison of MRI and 123I-FP-CIT SPECT for the evaluation of MSA-P clinical severity.

The aim of the present study was to compare the efficacy of magnetic resonance imaging (MRI) and 123I-labeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane single photon emission computed tomography (123I-FP-CIT SPECT) for determining the clinical severity of patients with multiple system atrophy with Parkinsonism (MSA-P). MRI and 123I-FP-CIT SPECT images from 17 patients with MSA-P as diagnosed using the Unified MSA Rating Scale part IV (UMSARS IV) score were compared. Brain MRI scans were available for all 17 patients and 123I-FP-CIT SPECT images were available for 12 patients. Putaminal atrophy (PA), hyperintense putaminal rim (HPR), hyperintense pons (hot cross bun sign, HCB), atrophy of the cerebellar vermis and hemisphere (cerebellar atrophy, CA) and other abnormalities were evaluated in the MRI scans. Distribution of striatal uptake (SU) and the specific binding ratio (SBR) on each side of the bilateral striatum were evaluated using 123I-FP-CIT SPECT images. No significant associations were observed between HPR, HCB, CA and UMSARS IV score. However, the frequency of PA increased significantly with higher UMSARS IV score (P<0.05). No significant association was observed between UMSARS IV score and SBR. The results of the present study suggest that PA, which is known to be a diagnostic indicator for MSA-P, may be used to determine the clinical severity of MSA-P with greater efficacy than other MRI findings, including HPR, HCB and CA and 123I-FP-CIT SPECT results.