Research for the characterization of brain tissue damage due to ischemia using MRI and MRS

点击翻译按钮获取中文摘要

It is very important to evaluate the extent of brain injury after ischemia for the management of stroke patients. MR imaging can provide the information based on brain perfusion and metabolic change about the brain at ischemic risk. The purpose of the study was to investigate the effectiveness of MR perfusion and MRS for the assessment of brain tissue damage induced by the ischemic insult. We have approached this research using both animal model with whole brain reperfusion and clinical cases with chronic occlusive cerebrovascular disease. In animal models, we have observed the decrease of NAA in 2-3 weeks and transient increase of Glx after ischemic event (N=5). Although the number of rats studied were limited, the results seemed to reflex the loss of neuronal tissue is long process and to be useful index for the tissue damage after ischemic insult. As a clinical application, we have implemented continuous arterial spin labeling (CASL) sequence on clinical MR scanner, which provide non-invasive means of CBF measurements. In order to validate the CASL method, we have compared the CBF values from CASL and CO_2 PET in patients with chronic occlusive cerebrovascular disease. Eleven patients were studied with CASL and conventional MRI. In all patients, there was a significant correlation between CBF values from CASL and PET(r=0.71±0.07, P<0.001). Quantification of CBF using CASL was feasible and reasonable, even when employed in a routine clinical setting.