Cerebral Blood Volume in Acute Brain Infarction

Abstract

Background and Purpose —The aim of this study was to correlate the abnormality in cerebral blood volume (CBV) measured by dynamic susceptibility contrast-enhanced MRI with that in cerebral blood flow (CBF) estimated by single-photon emission CT with [ 99m Tc]hexamethylpropylenamine-oxime in patients with acute ischemic stroke. Methods —Nine patients with unilateral occlusion of either the middle cerebral artery or the internal carotid artery (4 men and 5 women; mean±SD age, 74.4±11.6 years) were studied within 6 hours after stroke onset. The relative CBV (relCBV) and CBF (relCBF) in the lesions were defined relative to the contralateral mirror regions. Results —In the brain regions with mild (relCBF ≥0.60), moderate (0.40≤relCBF<0.60), and severe (relCBF <0.40) hypoperfusion, the mean relCBV values were 1.29±0.31, 0.94±0.49, and 0.30±0.22, respectively. The relCBV was significantly elevated in the brain areas with mild hypoperfusion ( P <0.001) and significantly reduced in the brain areas with severe hypoperfusion ( P <0.001). The relCBF was significantly better than the relCBV in predicting the evolution of infarction ( P <0.02). The probability of evolving infarction for the hypervolemic (relCBV >1.0) regions was significantly lower than that for hypovolemic (relCBV <1.0) regions in the relCBF range between 0.40 and 0.50 ( P <0.02). Conclusions —In acute ischemic stroke within 6 hours of onset the CBV can be either increased, normal, or decreased, depending on the severity of hypoperfusion. The increased CBV has a protective effect on evolving infarction. Although the CBF is a better predictor of tissue outcome, the CBV measurement may help detect potentially salvageable brain tissue in the penumbra with compromised blood flow.