Investigation of morphological change of lateral and midline fluid percussion injury in rats, using magnetic resonance imaging

OBJECTIVE: Investigating the time course of morphological changes in experimental traumatic brain injury (TBI) in vivo helps to clarify the mechanism of TBI and develop new therapeutic modalities. We examined the morphological changes in experimental TBI, using magnetic resonance imaging (MRI) in a rat model. METHODS: We produced lateral fluid percussion injury (LFP) and midline fluid percussion injury (MFP) in rats, using the Yamaki fluid percussion device. The rats were divided into four groups: LFP, MFP, sham LFP, and sham MFP. MRI was performed with a 4.7-T magnetic resonance apparatus 2 days and 90 days after the induction of injury. T1-, T2-, and T2*-weighted images were obtained using a surface coil. RESULTS: Hemorrhage, contusion, and brain edema in LFP models were detected on the 2nd day after injury, and the necrotic tissue was absorbed and replaced by cerebrospinal fluid on the 90th day. In MFP animals, we detected a small hemorrhage in the corpus callosum with minimal brain edema around the hemorrhage on the 2nd day after injury, and on the 90th day, enlarged ventricles and cisterns were observed, indicating brain atrophy. CONCLUSION: MRI, therefore, is useful for plotting morphological changes in experimental TBI in vivo. We report the novel and clinically important finding of brain atrophy after experimental TBI.