title: Intracranial hematomas: imaging by high-field MR.
abstract: Twenty intracranial hematomas between 1 day and over 1 year old were imaged using magnetic resonance at 1.5 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 acute (less than 1 week old), subacute (greater than 1 week and less than 1 month old), or chronic (greater than 1 month old). Acute hematomas were characterized by central hypointensity on T2-weighted images (WIs). Subacute hematomas had peripheral hyperintensity on T1-WIs and then on T2-WIs. This hyperintensity proceeded to fill in the hematoma in the chronic stage. In subacute and chronic hematomas, there was hypointensity on T2-WIs in the immediately adjacent part of the brain. On T2-WIs of acute and subacute hematomas, the nearby white matter was characterized by hyperintensity, consistent with edema. A different mechanism is proposed for each of the three characteristic intensity patterns. Two of these mechanisms increase in proportion to the square of the magnetic field magnitude.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002543:Cerebral Hemorrhage / Q000175:diagnosis*; D002648:Child; D005260:Female; D006407:Hematoma, Epidural, Cranial / Q000175:diagnosis; D006408:Hematoma, Subdural / Q000175:diagnosis; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D013997:Time Factors