Repeat cerebral blood volume assessment with first-pass MR imaging

The feasibility of performing multiple first-pass studies with dynamic, contrast material-enhanced magnetic resonance (MR) imaging was evaluated in a cat model of acute middle cerebral artery (MCA) ischemia. Two dynamic series of SSFP (steady-state free precession) images were acquired in each animal (n = 5) with a conventional 1.5-T imager. The initial first-pass study was acquired at 60 minutes after MCA occlusion, and the second study at 70 minutes, with each performed during an intravenous bolus injection of a 0.5 mmol/kg dose of gadoteridol. In both first-pass studies, differentiation of normal and ischemic gray and white matter was highly statistically significant. At a threshold of P<.01, no statistically significant difference in the peak signal intensity between the first and second studies was noted. A difference between the two studies in the recovery to baseline was seen, presumably due to T1 effects. First-pass MR studies can be repeated within the time frame of a single clinical examination, expanding their utility.