RADIOACTIVE MICROSPHERE VALIDATION OF A VOLUME LOCALIZED CONTINUOUS SATURATION PERFUSION MEASUREMENT

Detre et al. (Magn. Rason. Mad. 23, 37-45 (1992)) and Zhang at al., (M agn. Rason. Mad. 25, 362 (1992)) have recently demonstrated a techniqu e for the measurement of regional cerebral blood flow (rCBF) based on the continuous saturation (or inversion) of the arterial blood supply to the brain in rats at 4.7 T. In the work reported here, we combined this technique with volume localized (PRESS) readouts to benefit from recording ''perfusion'' signals averaged over a larger volume, resulti ng in rapid acquisition of data with sufficient signal-to-noise ratio for application at 2.0 T. In 10 baseline flow measurements, the mean e rror between the NMR technique and the microsphere flow measurement wa s -1.5% with a standard deviation of 15.2%. For five measurements obta ined with occlusion of the middle cerebral artery, the mean error was -32.4 +/- 20.2%. Perfusion measurements from a single animal under hyp ercapnic conditions indicated that the NMR technique could underestima te rCBF at high flow rates. An error analysis of the NMR perfusion mod el is also presented,along with results for typical parameters encount ered at 2.0 T.