1993 Volume 30 Issue 4 Pages 317-324
It is known that asymptomatic MRI lesions of the brain are found in elderly subjects, but the significance of the lesions has not been determined. In previous reports, the prevalence of MRI lesions varied from 11% to 59%, but many of the authors indicated a close relationship with cerebrovascular risk factors. We evaluated 76 elderly subjects (over 60 years old, average age±SD was 66.7±4.5) without a history of cerebrovascular disease and dementia, and determined the prevalence of periventricular (PVH), white matter (WMH) and pontine (PH) hyperintensity and risk factors. The severity of MRI lesion was evaluated in T2-weighted images by Fazekas' scoring method of MRI hyperintense lesions. PVH, WMH and PH were graded visually from 0 to 3 by the author and these points are added to the MM score. In T1-weighted images, we also measured the diameter of the third ventricle, frontal horn and body of the lateral ventricle. Our results were that 62% of subjects had PVH, 64% had WMH and 8% had PH. In regard to risk factors, 38% of subjects had hypertension, 17% had diabetes mellitus, 8% had ischemic heart disease. The PVH(+)group was significantly older (p<0.01) and had larger lateral ventricles (p<0.05) than the PVH(-) group. The WMH(+)group was significantly older (p<0.05) and had higher risk of cerebrovascular disease (p<0.05) than the WMH(-)group. The MRI score was related, but not significantly, to a history of hypertension, diabetes mellitus and ischemic heart disease. The MRI score and index of ventricular enlargement correlated with age (p<0.05). In conclusion, PVH was related to aging and WMH was related to both aging and cerebrovascular risk factors. Therefore, PVH and WMH were suspected to have different pathogenesis and WMH was more closely related to risk factors. Our scoring method permits evaluation and comparison MRI lesions of different groups.
