Temporal changes in perihematomal apparent diffusion coefficient values during the transition from acute to subacute phases in patients with spontaneous intracerebral hemorrhage.

INTRODUCTION: Diffusion-weighted imaging (DWI) studies focusing on apparent diffusion coefficient (ADC) abnormalities have provided conflicting results about the nature and fate of perihematomal edema. METHODS: We investigated 35 patients with supratentorial spontaneous intracerebral hemorrhage (SICH) by using DWI scanning obtained at 48 h and 7 days after symptom onset. Regional ADC (rADC) values were measured in three manually outlined regions of interest: (1) the perihematomal hyperintense area, (2) 1 cm of normal appearing brain tissue surrounding the perilesional hyperintense rim, and (3) a mirror area, including the clot and the perihematomal region, located in the contralateral hemisphere. RESULTS: rADC mean levels were lower at 7 days than at 48 h in each ROI (p < 0.00001), showing a progressive normalization of initial vasogenic values. Perihematomal vasogenic rADC values were more frequent (p < 0.00001) at 48 h than at 7 days, whereas perihematomal cytotoxic and normal rADC levels were more represented (p < 0.02 and p < 0.001, respectively) at 7 days than at 48 h. A neurological worsening was more frequent (p < 0.02) in patients with than in those without perihematomal cytotoxic rADC values at 7 days. CONCLUSION: Our findings suggest that the transition from acute to subacute phases after SICH is characterized by a progressive resolution of perihematomal vasogenic edema associated with an increase in cytotoxic ADC values. In the subset of patients with perihematomal cytotoxic rADC levels in subacute stage after bleeding, irreversible damage development seems to be related to poor clinical outcome.