Experimental Study Of3.0T Susceptibility Weighted Imaging, Diffusion Weighted Imaging And Diffusion Tensor Imaging In The Cerebral Blast Injury Of The Rabbits

Cerebral blast injury primarily manifests as hemorrhagic foci, non-hemorrhagic foci and white matter fiber injury, but CT and routine MRI cannot find prophase disease easily, however susceptibility weighted imaging, diffusion weighted imaging and diffusion tensor imaging can showed the disease early. So it is important to investigate the value of susceptibility weighted imaging (SWI), diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) in diagnosis of hemorrhagic foci, non-hemorrhagic foci, and white matter fiber injury early after blasting in rabbits, It also studies the hemorrhagic foci, and non-hemorrhagic foci. At the same time, the relationship of ADC value, FA value and it’s living time also researched. Diffusion tensor tracking showed the injury categories of white matter fiber injury after its blasting, It provides a referring basis in the early diagnosis, treatment and forecast prognosis of cerebral injury. Thirty New Zealand rabbits were selected, and model of cerebral blast injury was established. CT, routine magnetic resonance imaging (MRI), SWI, DWI and DTI were performed after their injury, and various analyses of region of interest were conducted with multiplanar postprocessing technology Functool2Software. The cerebral histopathological changes were observed, and contrast analyses were carried out with findings from SWI, DWI and DTI of the same plane. Position, number, form, ADC value, FA value and injury categories of white matter fiber injury were recorded. The data was input and analyzed by using SPSS17.0statistical software. Of the30rabbits, there were no abnormal cerebral imaging findings in6rabbits by CT, T1WI and T2WI, only gases and an large area of hemorrhage were showed in CT, and there was no abnormal in2of the6rabbits by SWI, DWI, DTI. In30rabbits,22,102,221,738hemorrhagic focuses were detected by the differences of CT, T1WI, T2WI, SWI. The number of cerebral microbleeds detected by SWI was significantly larger than those revealed by conventional T1WI, T2WI (x2=10.00, P<0.010), SWI imaging shows punctiform (315/42.7%), lamellar(218/29.5%), slinar (205/27.8%) hypointensity, the clear margin. Sensibility, and specificity of CT, T1WI, T2WI, SWI were compared by using receiver operating curve (ROC), They were showed as:38.5%,37.5%;77.5%,64.5%;87.5%,53.1%;96.1%,90.0%. It show there is a direct correlation between the number of hemorrhagic focus and the survival time of the rabbits by using SWI imaging detecting (r=-0.667, P<0.05). In30rabbits,0,49,91,189non-hemorrhagic focus were detected by the methods of CT, T1WI, T2WI, Among them, DWI shows non-hemorrhagic focus is most. DWI imaging detects much more no hemorrhagic focuses than routine T1WI, T2WI(x2=10.01, P<0.01), No bleeding lesion was displayed slightly hypointensity or hypointensity on T1WI under MRI checking, also hyperintense on T2WI, DWI imaging show bright-White, border was sharper. DWI imaging shows punctiform (54/28.5%), lamellar (102/54.0%), slinar (33/17.5%) hyperintense in24rabbits. Sensibility, specificity of T1WI, T2WI, SWI were compared using receiver operating curve(ROC), Sensibility, specificity discern are12.5%,27.3%;73.1%,68.7%;100%,97.7%. negative correlation was showed between the Number of hemorrhagic focus and live time of the rabbits SWI imaging detecting (r=-0.829, P<0.05). DTI shows ADC value, FA value decrease in measuring the region of interest after blast injury, especially in endocorpus region, they decreased predomindtly (discern:t=9.6, P<0.01; t=22.29, P<0.01). It was linear correlation between ADC value, FA value of Cerebral white matter the brain stem decreasing degree and live time of the rabbits (discern:r=0.53, P=0.05; r=0.13, P=0.03; r=0.0.25, P=0.04; r=0.27,P=0.02). The abnormality of cerebral white matter could be classified:color abnormality of ornamental code (2/30,6.67%), deficiency/breakage+displacement(8/30,26.67%), rare+deficiency/breakage (6/30,20.00%), and color abnormality of ornamental code+deficiency/breakage+displacement (14/30,46.67%). The result indicated, cerebral balst injury often has closed cerebral injury and openness cerebral injury at the same time, constitutional injury originates from explosion shock impact on cerebral; SWI, DWI can detected hemorrhagic foci, non-hemorrhagic foci, and their position, number, form sensitively. It was negative correlation between number, position of hemorrhagic foci, non-hemorrhagic foci and the condition of severity, Prognosis. ADC value, FA value play important roles in the development progression of severity, and increase the risk; So diffusion tensor tractography (DTT) would can the abnormal cerebral white matter fiber clearly and directing, DTT would provide valuable directions for the clinical diagnosis.