[Magnetic resonance tomography (1.5 T) of traumatic extracerebral hematomas]

The advantages of magnetic resonance imaging (MRI) in the diagnosis of subacute and chronic traumatic extracerebral hematomas are described. The characteristic changes in signal intensity for hematomas depend on the magnetic properties of hemoglobin and its derivatives, which shorten the relaxation times and decrease the homogeneity of the local magnetic field. MRI is superior in detecting and depicting the extent of small hematomas adjacent to the skull. Changes in signal intensity with time allow rough estimation of the age of a hematoma. Small hemorrhages were often found (missed by CT) that were contralateral to chronic subdural hematomas.