Magnetic resonance imaging characteristics of hyperacute hemorrhage in the brain and spine.

Five distinct stages have been defined for the magnetic resonance (MR) appearance of intraparenchymal hematomas in the brain: hyperacute, acute, early subacute, late subacute and chronic. Despite the extensive study of the evolution of hematomas there has been little attention given to the MR appearance of the posthemorrhagic state within the initial hours after the hemorrhage occurs. We discuss and illustrate the MR imaging characteristics of hyperacute hemorrhage. Five cases of hyperacute intraparenchymal hemorrhage, one intracranial subdural and one intraspinal lumbar epidural hemorrhage are presented.