Temporal evolution of diffusion after spontaneous supratentorial intracranial hemorrhage.

BACKGROUND AND PURPOSE The evolution of apparent diffusion coefficient abnormalities during supratentorial intracranial hemorrhage in normal appearing brain tissue has not been described. Recent investigations using diffusion imaging have revealed increased apparent diffusion coefficient in perihematomal tissue. We report brain tissue abnormalities beyond the visibly abnormal region ipsilateral and contralateral to the hematoma. This preliminary effort should generate meaningful clinical prognostic indicators for moderate size hemorrhages in large scale studies. METHODS Using the neurology patient encounter database at a tertiary care hospital, we retrospectively identified patients who presented with acute focal neurologic deficits, had CT scans of the head that confirmed spontaneous intracranial hemorrhage, and had a MR images obtained within the first 6 hr to 30 days postictus. The regions identified as targets of this investigation were the hemorrhage and surrounding T2 signal intensity abnormality and the visibly normal supratentorial cerebral tissue. RESULTS Ninety-five patients were admitted during a period of 25 months. Fifteen patients met the criteria for the study. Elevated whole brain diffusion was shown as early as 6 hr after intracranial hemorrhage. This increase in diffusion was comparable in both hemispheres. Diffusion values in the lesion (hematoma plus T2 signal intensity abnormality) increased slowly with peak increases noted 2 to 3 days after the ictus. CONCLUSION Diffuse early cerebral response occurs in normal appearing brain tissue both ipsilateral and contralateral to the visibly abnormal hematoma, manifested by increased apparent diffusion coefficient. This response is present before the local response is fully developed. Supratentorial intracranial hemorrhage results in an early diffuse brain response with increased apparent diffusion coefficient in normal appearing brain.