Serial diffusion-weighted MR imaging and ~1H-MRS around hematoma in pigs with frontal lobe hemorrhage

AIM: To determine the characteristics of perilesion edema during 1-7 days in pigs with intracerebral hemorrhage (ICH). METHODS: With injection of 2.5 mL autologous artery blood into right frontal lobes, 15 pigs (10-15 kg) had fluid-attenuated inversion-recovery (FLAIR), diffusion weighted imaging (DWI) and 1H-magnetic resonance spectrum ( 1H-MRS) by 1.5 T MR at 24 hours (n=15), at 72 hours (n= 9) and on day 7 (n=5). In 4 animals, blood-brain barrier permeability was observed by leakage of Evan’s blue at 24 hours (n= 4). RESULTS: The edema was located around hematoma on the sequence of FLAIR at 24 hours after ICH. The perilesional apparent diffusion coefficiency (ADC) increased and no lactic acid peak was observed by 1H-MRS from 24 hours to day 7 in all the animals but one. CONCLUSION: During 1-7 days after ICH, the vasogenic edema dominates around the hematoma. Only in case of massive hemorrhage, ischemia may coexist.