PURPOSE: To determine changes in the signal intensity of intracerebral hemorrhagic lesions according to the time interval, between the onset of symptoms and MR imaging in the T1-weighted (T1W1), T2-weighted (T2W1) and diffusion-weighted modes. MATERIALS AND METHODS: Thirty-four patients with hemorrhagic stroke who underwent DWI and conventional MRI were involved in this study. Hemorrhagic phase was determined according to the time interval between the onset of symptoms and MR scanning, and was as follows: acute (3 days or less): eight patients); early subacute (7 days or less): ten patients; late subacute (4 weeks or less): seven patients; early chronic (3 months or less) : four patients); and late chronic (more than 3 months): five patients. Using a 1.5T MR imager and the single-shot echo-planar imaging technique, T1-weighted, fast spin-echo T2-weighted, and diffusion-weighted were obtained. In all cases qualitative signal intensity (SI) at the center of a lesion was recorded, and the ratio between this and normal brain parenchyma was calculated. RESULTS: SI at the center of a lesion was found to be iso or high/high/high (T1WI/T2WI/DWI) in five of eight acute-phase cases (interval of 24 hours or less) and low/low/low in the remaining three (interval of 72 hours or less). Other signal intensities were as follows: early subacute phase: high/low/low (all ten cases); late subacute phase: high/high/high (all seven cases); early chronic phase: high/high/high (all four cases); late chronic phase: low/high/low (all five cases). Mean SIRs were as follows: in the five acute-phase cases in which SI was iso or high: 1.42+/-0.78 / 2.58+/-0.84 / 1.35+/-0.08 (T1WI / T2WI / DWI); in the remaining three acute-phase cases: 0.94 +/-0.18 / 0.63+/-0.16 / 0.27+/-0.10; in the early subacute phase, 1.35+/-0.01 / 0.97+/-0.21 / 0.86+/-0.22 in early subacute phase, 1.58+/-0.04 / 1.54+/-0.09 / 1.44+/-0.14; in the early chronic phase: 1.26+/-0.11 / 1.06+/-0.14 / 0.97+/-0.12; and in the late chronic phase: 0.65+/-2.23 / 1.51+/-0.12 / 0.23+/-0.18. CONCLUSION: The DWI findings of intracerebral hemorrhage reflect the findings of T2WI. When interpreting the DWI findings in patients with intracerebral hemorrhage, an understanding of the temporal evolution of this is very helpful.