[Usefulness of T2* weighted magnetic resonance image in the diagnosis of head injury on chronic stage].

T2* weighted gradient echo image has heightened diagnostic sensitivity to hemorrhage, which is attributed to magnetic susceptibility-induced static field inhomogeneities arising from paramagnetic blood breakdown products such as hemosiderin, which shorten T2*. We examined 4 cases of head injury in chronic stage by T2* weighted images and assessed the clinical application of this sequence for diagnosis of the intracranial lesion. All patients underwent CT scan on acute stage and long-term follow up was performed. In all cases, abnormally low signals in the brain and subarachnoid space were more conspicuous with the T2* weighted image than with any of the conventional sequences. In 2 cases with diffuse axonal injury, of which lesions were not detected on acute stage CT scan, hypointensity area was clearly demonstrated in the cerebral peduncle and corpus callosum on T2* weighted images. Selection of T2* weighted image into the routine MR examination of patients with chronic stage of the head injury is recommended.