Clinical Value Of Mr Enhanced T2*Star Weighted Angiography Sequece In The Diagnosis Of Diffuse Axonal Injury

Objective:To assess the value of MR enhanced T2*star weighted angiography (ESWAN) sequence by compare with that of conventional MR sequences(T1WI、T2WI、FLAIR) in the diagnosis of diffuse axonal injury (DAI).Methods:27patients with diffuse axonal injury of brain underwent MRI scanning (GE Signa TwinSpeed1.5T), which included T1WI, T2WI, FLAIR and ESWAN sequences. The numbers of cerebral DAI lesions which was determined for the following locations: grey/white matter of frontal/temporal/parietal/occipital lobe, cerebral ganglia, corpus callosum, basal ganglia, brainstem and cerebellum and was compared among the different sequences in each patients. the characteristic signals and distribution of lesions were analyzed. We dichotomized the patient into nonsevere group(GCS>8, n=11) and severe group(GCS<8, n=16) on the basis of Glasgow coma scale, and dichotomized the patient into favorable prognosis group and unfavorable prognosis group according modified Rankin score(mRS)6months later after injury. Number of DAI lesions in whole cerebrum and cerebrum positional involved in ESWAN were respectively analyzed with Glasgow Coma Scale score and modified Rankin score. SPSS11.0statistical package was used to process the date, Mann-Whitney u test and Spearman test was selected, P<0.05means a statistically significant difference.Results:The averaged detected numbers of DAI lesions were0.35±0.27on T1WI,1.74±0.81on T2WI,3.04±2.11on FLAIR, and7.25±4.86on ESWAN respectively. The detected numbers of DAI lesions on ESWAN was the highest and significantly higher than that on SE T1WI,TSE T2WI and FLAIR, respectively (U=-6.324,-5.752,-4.357, P<0.01). The invisible pinpoint hemorrhagic lesions on conventional MRI were well displayed on ESWAN sequence image, and the boundary of lesions demonstration is clearer.DAI hemorrhagic lesions most located in the junctional zone of cortex and medulla, basal ganglia, corpus callosum, brain stem and cerebellum. The MR features of DAI hemorrhagic lesions showed in ESWAN were hypointensity signal in shape of needle tip, mottling, nodular. The detected numbers of DAI lesions in whole cerebrum and cerebrum positional involved on severe group was significantly higher than on the nonsevere group.(U=-3.083,-3.727, P<0.05), The detected numbers of DAI lesions in whole cerebrum and cerebrum positional involved on unfavorable prognosis group was significantly higher than on the favorable prognosis group.(U=-4.344,-3.073, P<0.05); A significant negative correlation was found between the sum lesions and cerebrum positional involved on ESWAN with GCS score (r=-0.867,-0.772, P<0.05), A significant positive correlation was found between the sum lesions and cerebrum locations involved on ESWAN with MRS score (r=0.657,0.583, P<0.01). Conclusion:1. ESWAN is sensitive to detected the hemorrhagic lesions of DAI, ESWAN can visualize more and smaller DAI lesions clearly, which should be used as the routine sequence in the MRI examination for the patients who suspiciously have DAI.2. The number of lesions and cerebrum positional involved on ESWAN is closely correlated with GCS score and MRS score, ESWAN is a valuable tool in diagnosis and evaluation of prognosis for DAI patients.