Abnormal Hemispheric Blood Flow and Metabolism in Cerebrovascular Disease. I. Disordered Patterns of Hemispheric Metabolism

Hemispheric blood flow (HBF) and metabolism were studied in 46 patients with various types and stages of ischemic cerebrovascular disease and were found to be abnormal in all patients, including those with transient ischemic attacks. Bilateral depression of HBF and metabolism was observed in association with acute unilateral cerebral infarction. Hemispheric respiratory quotient (HRQ) was higher in the ischemic hemisphere than in the healthy side. The degree of elevation of HRQ on the diseased side correlated well with the acuteness of infarction, increasing age of the patients, and the severity of the neurological deficit. However, the HRQ in the healthy hemisphere was lower than unity, which suggests that substances other than glucose were being metabolized. The high hemispheric glucose:oxygen ratio (HG:O) correlated well with the severity of infarction and the age of the patient. Patients with brain stem ischemia had the lowest HBF values, suggesting that central neurogenic vasomotor control had been impaired or that diaschisis was greater in those with brain stem lesions than in patients with other types of lesions. A significant uptake of β-hydroxybutyrate was observed in both the healthy and diseased hemispheres but was highest in the healthy side. Evidence for abnormal cerebral metabolic patterns, such as anaerobic glycolysis, in patients with cerebrovascular disease, and oxidation of nonglucose substances such as β-hydroxybutyrate, are discussed.