Prevalence of MR evidence of diffuse axonal injury in patients with mild head injury and normal head CT findings.

TLDR

Diffuse axonal injury lesions are thought to underlie postconcussion syndrome in many patients with moderate to severe head injury. This study aimed to determine the prevalence of MR‑detected diffuse axonal injury in patients with mild head injury who have normal head CT scans. Twenty consecutive mild head injury patients with normal CTs underwent 1.5‑T MRI, and two readers evaluated the images for diffuse axonal injury. MR imaging revealed diffuse axonal injury in 30% of patients, with high‑signal foci on T2‑weighted sequences in 15% and hypointense hemorrhagic shear foci on T2*‑weighted sequences in 20%, indicating that some patients with normal CTs do have DAI.

Abstract

PURPOSE To assess the prevalence of MR evidence for diffuse axonal injury at 1.5 T in patients with normal head CT findings after mild head injury. METHODS Twenty consecutive patients with mild head injury (Glasgow Coma Scale, 13 to 15; no subsequent deterioration, loss of consciousness RESULTS The readers agreed that abnormalities compatible with diffuse axonal injury were present in the white matter of 6 (30%) of 20 patients (95% confidence interval, 12% to 54%). Both readers agreed that foci of high signal intensity were present on the T2-weighted spin-echo sequence in 3 (15%) of the 20 cases (95% confidence interval, 3% to 38%) and that foci of hypointensity compatible with hemorrhagic shear injury were present on the T2*-weighted sequence in 4 (20%) of the 20 patients (95% confidence interval, 6% to 44%). Both types of abnormality were noted by the readers in one patient. CONCLUSIONS MR shows evidence of diffuse axonal injury in some patients with normal head CT findings after mild head injury. These lesions may represent the pathologic substrate underlying the postconcussion syndrome that occurs in many patients with moderate to severe head injury.