Cerebral blood volume in acute brain infarction - A combined study with dynamic susceptibility contrast MRI and Tc-99m-HMPAO-SPECT

Background and Purpose-The aim of this study was to correlate the abnormali ty in cerebral blood volume (CBV) measured by dynamic susceptibility contra st-enhanced MRI with that in cerebral blood flow (CBF) estimated by single- photon emission CT with [(99m)]hexamethylpropylenamine-oxime in patients wi th acute ischemic stroke. Methods-Nine patients with unilateral occlusion of either the middle cerebr al 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 rel ative CBV (relCBV) and CBF (relCBF) in the lesions were defined relative to the contralateral mirror regions. Results-In the brain regions with mild (relCBF greater than or equal to 0.6 0). moderate (0.40 less than or equal to 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 signif icantly 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 hypop erfusion. The increased CBV has a protective effect on evolving infarction. Although the CBF is a better predictor of tissue outcome, the CBV measurem ent may help detect potentially salvageable brain tissue in the penumbra wi th compromised blood flow.