Experimental acute cerebral ischemia with reperfusion. Evaluation with gadolinium-texaphyrin.

ABSTRACT

RATIONALE AND OBJECTIVES: The authors explore the potential usefulness of the new contrast medium gadolinium (Gd)-texaphyrin (PCI-0101) in magnetic resonance imaging of experimental acute cerebral ischemia with reperfusion. METHODS: Four New Zealand white rabbits underwent 2 hours of transorbital occlusion of the left internal carotid, anterior, and middle cerebral arteries, followed by 2 hours of reperfusion with normal saline. Immediately thereafter, the rabbits were injected with 25 mumol/kg of 2 mmol/L Gd-texaphyrin and killed by barbiturate overdose. Postmortem T1- and T2-weighted coronal scans were performed at 1.5 Tesla and correlated with histopathologic findings. RESULTS: Postcontrast T1-weighted images showed high signal within extensive cortical and basal ganglia infarcts. Areas of high signal on T1-weighted images were less extensive than on T2-weighted images, and corresponded to only a portion of the region of neuronal damage seen histologically. Signal intensity of infarcted brain on postcontrast T1-weighted images was significantly greater than normal brain in the contralateral hemisphere (P < 0.0014). CONCLUSIONS: Experimental reperfused infarcts only 2 hours old demonstrate contrast enhancement with Gd-texaphyrin.