Thin section MR study of the basal ganglia in the differential diagnosis between striatonigral degeneration and Parkinson disease

Purpose: Signal abnormalities within the putamen in MRI have been related to tissue degeneration in the striatonigral variant of multiple system atrophy (MSA-P). While previous work demonstrated the high specificity of these MR findings, sensitivity rates were unsatisfactory. We evaluated the specificity and sensitivity of an acquisition protocol using thin section MRI to differentiate MSA-P from Parkinson disease (PD). Method: Axial 3-mm-thick conventional T2 and proton density spin echo images at the level of basal ganglia were acquired at 1.5 T in 24 patients with MSA-P and 27 patients with PD. Results: We found an abnormal putaminal T2 hypointensity in 21 of 24 MSA-P patients (87.5% sensitivity) and a proton density hyperintensity in 20 of 24 MSA-P patients (83.3% sensitivity). Three among 27 PD patients had an abnormal putaminal T2 hypointensity (88.8% specificity) and there were no proton density abnormalities (100% specificity). Conclusion: Our thin section conventional spin echo protocol showed a substantial increase in MR sensitivity compared with previous reports. We believe that a better depiction of even mild signs of degeneration in the putamen may allow a more widespread use of this technique in the differential diagnosis of parkinsonisms.