1991 Volume 28 Issue 5 Pages 627-633
Recent positron or single photon emission computed tomographic studies have demonstrated that the impairment of regional hemodynamics or metabolism in cerebrovascular disease is not limited to the focal lesion, but also involves more remote areas. The present study evaluated cerebral blood flow in areas remote from the primary lesion in patients with subcortical cerebrovascular disease, and assessed correlations with the clinical features. Twenty patients aged 61∼89 (mean, 74.7±6.7 years) were divided into the L group (lacunar infarction in deep penetrating arterial territory, n=7), the NL group (non-lacunar subcortical infarction caused by main trunk occlusion or severe stenosis, n=6), and the H group (putaminal or thalamic hemorrhage, n=7). Ipsilateral cortical and contralateral cerebellar blood flow were assessed using single photon emission computed tomography with 123I-IMP. Although only some patients of the L group showed a mild reduction of ispilateral cortical blood flow, most of the patients in the NL and H groups showed a moderate or severe flow reduction. The cortical blood flow reduction was suggested to be caused by several mechanisms, including brain edema, a decreased perfusion pressure associated with disease of large arteries, partial cortical neuronal damage, and deactivation. The degree of the flow reduction was considered to depend on the relative contribution of each of these factors. Contralateral cerebellar blood flow reduction, i.e., crossed cerebellar diaschisis, was observed more frequently and prominently in the NL and H groups than in the L group. Transneuronal depression through corticopontocerebellar pathways was suggested to be involved in the development of this phenomenon, since it was noted in patients with lesions involving the internal capsule or corona radiata. Neuropsychological impairment like aphasia or agnosia was associated with ipsilateral cortical blood flow reduction, and motor deficits seemed to be associated with ipsilateral cortical or contralateral cerebellar blood flow reduction. However, no correlation between cerebellar ataxia and contralateral cerebellar blood flow reduction was demonstrated. Thus, functional abnormalities affecting remote areas should be considered in patients with subcortical lesions.