Abstract:

Objective　To investigate the diagnostic efficacy of magnetic resonance diffusion-weighted imaging (DWI) on the injury characteristics of neurovascular unit (NVU) of hyperacute infarction of rabbit brain.　Methods　Fifteen New Zealand rabbits were randomly separated into two groups: the contrast group (n=5) and the experimental group (n=10). Micro-catheter was used to produce middle cerebral artery occlusion (MCAO) on the experimental group animals via internal carotid artery. According to different occlusion time, the experimental group was divided into 2 sub-groups (sub-group 0.5 h and 4 h) with 5 animals per group. All the animals underwent T2-flair and DWI scanning before and after MCAO. The imaging characteristics of DWI and the values of apparent diffusion coefficient (ADC) and relative apparent diffusion coefficient (rADC) were analyzed. After MRI, the animals were sacrificed for the Nissl′s staining, the glial fibrillary acidic protein (GFAP) and CD31 detection of brains.　Results　Compared with the contrast group, abnormal high intensity signal on DWI, low signal on ADC, unaltered T2-flair signal, high expression of GFAP were observed at sub-group 0.5 h in the right basal ganglia region. At sub-group 4 h, abnormal high intensity signal on DWI and low signal on ADC which appeared more intense than sub-group 0.5 h. T2-flair scanning showed high signal. The Nissl’s results showed that the number of Nissl’s body at the control group and sub-group 0.5 h appeared intact, while the number of Nissl’s body decreased and neurons were damaged at sub-group 4 h. The high expression of GFAP were observed. The values of ADC and rADC in sub-group 0.5 h were significantly different with those in sub-group 4 h. The value of rADC and the intensity of GFAP showed linear correlation (r=-0.672, P<0.01).　Conclusions　The DWI can diagnose accurately on hyperacute infarction of rabbit brain, and the DWI changes of relative time were consistent with the injury of NVU.

Key words: Diffusion-weighted imaging, Rabbit, Middle cerebral artery occlusion, Neurovascular unit