Diffusion-weighted MR Imaging in Closed Head Injury: High Correlation with Initial Glasgow Coma Scale Score and Score on Modified Rankin Scale at Discharge

PURPOSE: To determine whether diffusion-weighted magnetic resonance (MR) imaging findings and conventional MR imaging findings correlate with initial Glasgow Coma Scale score and score on modified Rankin scale at discharge. MATERIALS AND METHODS: Twenty-six patients (18 male and eight female patients; mean age, 25.2 years; age range, 4-72 years) with diffuse axonal injury were examined with diffusion-weighted MR imaging and with fluid-attenuated inversion recovery, T2-weighted fast spin-echo, and T2*-weighted gradient-echo sequences. All images were evaluated by two neuroradiologists in consensus. Tissue volume with trauma-related signal-intensity abnormality on images from each sequence, number of lesions for each sequence, number of lesions for all sequences, and number of lesions with reduced apparent diffusion coefficient were correlated with scores on Glasgow Coma Scale and modified Rankin scale. Involvement of brainstem, deep gray matter, and corpus callosum were also correlated with clinical scores. Spearman rank correlation coefficients (r) were calculated. RESULTS: The strongest correlation was between signal-intensity abnormality volume on diffusion-weighted images and modified Rankin score (r = 0.772, P <.001). The strength of this correlation did not improve when only volume of lesions with decreased apparent diffusion coefficient was considered. For lesion number, the strongest correlation was between lesion number on images acquired with all sequences and modified Rankin score (r = 0.662, P <.001). For lesion location, the strongest correlation was between lesion location in the corpus callosum and modified Rankin score (r = 0.513, P =.007). CONCLUSION: Volume of lesions on diffusion-weighted MR images provides the strongest correlation with a score of subacute on modified Rankin scale at discharge. Total lesion number also correlates well with modified Rankin score. In future, diffusion-weighted images may be useful in determining treatment strategies for acute head injury.