Measurement of cerebral blood volume with subtraction three-dimensional functional CT.

PURPOSE To implement a three-dimensional subtraction functional CT technique to permit rapid quantitative mapping of regional cerebral blood volume (CBV). METHODS The 3-D functional CT technique was implemented in a rabbit model using normal and ischemic animals. Two spiral data acquisitions were performed, one before and one during biphasic administration of contrast material. CBV maps were then produced on a voxel-by-voxel basis through the whole brain. RESULTS The average normal CBV was 3.3 +/- 0.4 mL/100 g (n = 7), and the regional values were 4.5 +/- 0.6 mL/100 g for cortical gray matter, 2.5 +/- 0.6 mL/100 g for white matter, and 3.7 +/- 0.4 mL/100 g for the basal ganglia. The CBVs in ischemic regions were 1.5 +/- 0.4 mL/100 g, 0.7 +/- 0.7 mL/100 g, and 1.8 +/- 0.9 mL/100 g, respectively. CONCLUSION Subtraction 3-D functional CT is a fast, potentially cost-effective method with which to assess whole-brain CBV. Because the data collected in 3-D functional CT imaging also can be used to produce large-vessel angiograms, its use in a clinical setting can provide a multiparametric study of cerebrovascular abnormalities that encompasses both large and small vessel circulations for patients being examined for stroke.