Measurement of cerebral blood volume via the relaxing effect of low-dose gadopentetate dimeglumine during bolus transit.

PURPOSE To quantify regional cerebral blood volume (rCBV) on the basis of the enhancement of blood proton relaxation rates after intravenous administration of gadopentetate dimeglumine. METHODS A series of sequential MR images on one section was recorded during bolus transit with a standard fast low-angle shot sequence. The signal-intensity curves were converted into corresponding concentration-time curves from which rCBV images were calculated. RESULTS The functional parameter images of rCBV were calculated pixel-by-pixel for two patients who had received a 1-second bolus injection of 1 mmol of gadopentetate dimeglumine. In a larger series of 62 patients, a mean blood volume of 4.6 +/- 1.6 vol% was determined for normal brain tissue. CONCLUSIONS The relaxing effect of a contrast agent can be used to determine blood volume quantitatively. The results are in agreement with those obtained by nuclear medicine techniques. The proposed method requires no special hardware, and can thus be implemented on clinical MR scanners.