Background: Aim of this study was to assess the role of diffusion-tensor magnetic resonance imaging (DT-MRI) in diagnosis and prognosis in severe diffuse axonal injury (DAI).
Materials and methods: The studies using 1.5 Tesla MR tomograph were performed on 2nd-17th days after injury in 22 patients with DAI and in 8 healthy volunteers. All patients were comatose in acute period (GCS 4-8), 11 had hemiparesis and in 4 had tetraparesis. Outcomes were evaluated after 6 months using GOS. Indices of diffusion coefficient (DCI) and fraction anisotropy (FA) were assessed bilaterally: in genu and splenium of corpus callosum, posterior limb of internal capsule (PLIC), cerebral peduncles, at the level of pons (along corticospinal tracts (CST).
Results: Significant decrease of FA (p < 0.05) along CST bilaterally was found in 7 patients without movement disorders comparing to analogous indices in the control group. Also statistically significant decrease of FA at the level of PLIC and cerebral peduncles was observed on the contralateral side in patients with hemiparesis (p < 0.01). In patients with tetraparesis FA was significantly decreased along CST bilaterally (p < 0.00001). Indices of FA in corpus callosum and along pyramidal tracts significantly correlated with outcomes in patients examined on 10th-17th day after injury (p < 0.01). In the whole group of patients mean indices of FA and DCI in the splenium of corpus callosum were significantly decreased (p < 0.01 and p < 0.05, respectively). 3D reconstruction of CST allowed to discover asymmetry of CST in 3 of 9 patients with hemiparesis on 1st-9th day after injury and in all 6 patients examined on 10th-17th day.
Conclusion: Indices of FA reflect the degree of integrity of white matter pathways with significant accuracy. Application of DT-MRI allows to reveal quantitative and qualitative alterations in white matter tracts and to assess their clinical and prognostic value in DAI.