Experimental Study Of Functional Magnetic Resonance Imaging On Reperfusion After Acute Cerebral Infarction In Rat

ObjectiveTo demonstrate the metabolic changes in S-D rat model of cerebral ischemiareperfusion by 1-hydrogen magnetic resonance spectroscopy (~1HMRS) bycomparison with findings on pathology and MRI, DWI, and the practical value of~1HMRS in evaluating cerebral ischemic injure and recovery degree after reperfusion.Materials and MethodsA total of 49 S-D rats were randomly divided into 7 groups, i.e., group A, B, C,D, E, F, G, with 7 rats in each group. Group A is a control group with sham operation.The rats from the rest 6 groups received a procedure of the transient middle cerebralartery oclusion (MCAO) by inserting a nylon thread with a small ball tip. All ratswere examined by T1WI, T2WI, DWI and ~1HMRS on a 1.5T MRI after theprocedure. Group B, C and D were the repeffusion group after 1 hr MCAO, and thetime points of MRI examination were 3, 6, 24 hrs after reperfusion. Group E, F andG were the reperfusion group after 2 hrs of MCAO, and the time points of MRIexamination were 3, 6, 24 hrs after reperfusion. After MRI examination, the brainsfrom four rats of each group were performed by 2,3,5-triphenyltetrazolium chloride(TTC) staining and three rats HE staining for pathological examinations.ResultsRats in group A showed normal appearance on T1WI, T2WI, DWI, ~1HMRS andpathological examination. Group B, C and D showed normal appearance on T1WIand slight high signal intensity on T2WI. In group E, F and G, high signal intensitylesion were seen on T2WI and DWI. The size of the lesion in the brain from group E, F and G with abnormal signal intensity on T1WI, T2WI, DWI was enlarged alongwith time going. In group B, C and D, ~1HMRS of focus showed no obvious changeof Choline (Cho) and Creatine (Cr), a decrease of N-acetyl-aspartate (NAA), and anincrease of Lactate (Lac). In group E, F and G, ~1HMRS of these focus showed asignificant decrease of NAA, an continuous increase of Lac, and a slightly decreaseof Cho and Cr.Conclusion~1HMRS is sensitive in detecting the dynamic changes of cerebral reperfusion invivo, it can quantitatively reflect cerebral ischemic injure and recovery degree afterreperfusion.