Abstract:

Objective  To evaluate the application values of magnetic resonance imaging (SWI) and diffusion tensor imaging (DTI) in the chronic stage of diffuse axonal injury (DAI). Methods  Three groups of people including 12 chronic DAI patients with normal CT and conventional MRI appearance, 15 patients with mild traumatic brain injury (mTBI) and 15 healthy volunteers (controls), were examined by GE Signa EXCITE Ⅱ 3.0 MR scanner. T2*GRE, SWI, and DTI were performed and the MR images were analyzed by 2 experienced radiologists. The number of microbleeds was counted and the values of FA were measured in various ROIs. Correlation analysis was performed between Glasgow outcome scale (GOS) scores, the number of microbleeds and FA values. Results  ① In the the DAI group, SWI detected more microbleeds than T2*GRE did（P＜0.01）. No microbleed was detected in the other 2 groups. ② Between DAI and mTBI groups, there were significant differences in the FA values in the ROIs(P＜0.05) except for the parietal lobe, thalamus and the splenium of corpus callosum. Between the DAI and control groups, there were significant differences in all of the ROIs(P＜0.05). ③　There was no significant difference between mTBI and the control groups(P＞0.05). ④　The GOS scores were correlated with the number of microbleeds（r=0.6775, P=0.0314） and the FA value in the genu of the corpus callosum（r=0.8360, P=0.0097）. Conclusion  SWI and DTI can reveal DAI more distinctly, and evaluate the extent of the injury.

Key words: Magnetic resonance imaging; Diffuse axonal injury; Susceptibility weighted imaging; Diffusion te