[Image changes of hemoglobin in acute and hyperacute intracranial hematoma during hyperintensive magnetic resonance].

36 intracranial hematomas between one hour and 7 days were imaged by using magnetic resonance at 1.0 T, with T1-and T2-weighted spin-echo pulse sequences. Characteristic intensity patterns were observed in the evolution of the hematomas, which could be staged as hyperacute (less than 24 hours) and acute (greater than 1 day and less than 7 days). Hyperacute stage could be subdivided into three phases, and hyperacute hematomas were characterized by hypointensity-mild hyperintensity-isointensity on T1-weighted images. Acute stage could be subdivided into three phases, and acute hematomas were characterized by hypointensity (DHB)-hyperintensity (MHB in intact RBC)-hyperintensity (free, undilute MHB in lysed RBC) on T1-weighted images. Acute hematomas were characterized by hypointensity (DHB)-obviously hypointensity (DHB + MHB in intact RBC)-hypointensity (DHB + free, undilute MHB in lysed RBC) on T2-weighted images. Different mechanisms were proposed for these characteristic intensity patterns of hyperacute and acute hematomas.