MRI of extracranial hematomas: preliminary observations

Thirteen patients (16 examinations) with extracranial hematomas (four mediastinum, three pelvis, two calf, two psoas muscle, one liver, one abdominal wall) were examined with magnetic resonance imaging (MRI). With the exception of an acute hematoma (less than 48 hr), which did not have a distinctive MRI appearance, subacute and chronic hematomas (up to 10 months' duration) had areas of high signal intensity on both T1- (TR 500/TE 30) and T2- (TR 1500/TE 90) weighted pulse sequences. The hematomas in 10 of the patients were also evaluated by computed tomography (CT). The MRI findings complemented those seen on CT. Low-intensity parts of the hematoma on both T1- and T2-weighted images corresponded to areas of high attenuation on CT, whereas high-intensity zones correlated with regions of low attenuation. This observation was more apparent on the T1-weighted images. While older hematomas did not exhibit areas of hyperdensity that would allow a specific diagnosis on CT, MRI did demonstrate regions of high signal intensity indicative of hemorrhage.