Experimental study on perfusion T2 weighted imaging with superparamagnetic iron oxide in hyperacute cerebral ischemia

Objective To determine the feasibility of superparamagnetic iron oxide (SPIO) perfusion T2WI for detecting hyperacute cerebral ischemia ZMethods Thirtyone rats were included 26 rats underwent right middle cerebral artery occlusion (MCAO) by Zea Longa's method, the other 5 rats were used as normal control group At 4050 minutes after the procedure of MCAO, pre and postperfusion of SPIO T2WI were performed SPIOI particle diameter 20 nm, SPIOII particle diameter 6-9 nm dose 06 mmol/kg iv(SPIOI 6/26 rats and SPIOII 20/26 rats) In 6 of 26 MCAO models, T2WI was obtained 24 hours after MCAO ResultsBZIn 50 minutes after MCAO, the findings of ischemic changes were either absent or subtle (37%) on T2WI before SPIO administration, but became marked on SPIOI perfusion T2WI (100%) and SPIOII perfusion T2WI (80%) The relative higher signal area on SPIO perfusion T2WI corresponded exactly to the area of definite ischemia seen on the black ink perfusion pathology, and also the infarction areas on 24 hours images seen on T2WI and HEstained brain slices Conclusions The results suggested that SPIO perfusion T2WI has the capability of detecting early stage of cerebral ischemia within 1 hour after cerebral artery occlusion SPIO serves as a negative contrast media in T2WI The contrast effect of SPIOI perfusion T2WI is better than that of SPIOII in hyperacute cerebral ischemia