[MRI in Parkinson's disease and vascular parkinsonism--study on the lesion of substantia nigra].

: We examined the magnetic resonance (MR) image of midbrain and striatum in 30 patients with Parkinson's disease (PD), 10 patients with vascular parkinsonism (VP) and 10 age-matched control subjects. Studies were performed on a high field strength (1.5 tesla) MRI unit. T2 weighted spin echo pulse sequence (TR2500ms/TE40ms) was used. We measured the width of the pars compacta signal in patients and controls on the basis of the method described by Duguid et al. Intensity profiles of a straight line perpendicular to the pars compacta through the center of the red nucleus were made on an image of the midbrain. We measured the width of the valley at half-height between the peaks of intensity representing the red nucleus and the crus cerebri-pars reticulata complex and used this as an index of the width of the pars compacta signal. The results were as follows: 1. The mean width of the pars compacta signal was 2.7 mm (SD = 0.3) in the PD group and 4.3 mm (SD = 0.6) in controls. The difference between the means was highly significant (p less than 0.01). While not significant statistically, there was a trend toward narrowing of the width of pars compacta signal of substantia nigra in the PD group as the Yahr's grade or disease duration progressed. In hemiparkinsonism, MRI revealed significant narrowing of the pars compacta signal on the contra-lateral side to the clinical predominant side compared with the ipsi-lateral side. 2. The mean width of the pars compacta signal was 3.9 mm (SD = 0.4) in the VP group, but the decrease was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)