title: High-field MR imaging of extracranial hematomas.
abstract: The MR features of 20 extracranial hematomas studied on a 1.5-T system and imaged with both short repetition-time/echo-time (TR/TE) and long TR/TE pulse sequences were reviewed. In four of five acute hematomas (those less than 7 days of age), signal intensity was markedly decreased on long TR/TE images and was either intermediate or slightly decreased on short TR/TR images. Fourteen subacute hematomas (7 days to 7 weeks of age) and one chronic hematoma (9 months) were studied. The appearance of the subacute lesions varied from intermediate to high intensity on short TR/TE sequences, but all demonstrated increased signal on long TR/TE sequences. A low-signal rim was noted at the margin of nine subacute lesions. In one patient with this finding, pathologic examination showed that the low-signal margin corresponded to a region containing hemosiderin-laden macrophages at the periphery of the hematoma. These results correlate well with those reported for intracranial hematomas examined at this field strength. We conclude that analysis of signal-intensity patterns at 1.5 T is useful in staging the evolution of hematomas.
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D006406:Hematoma / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007674:Kidney Diseases / Q000175:diagnosis; D008107:Liver Diseases / Q000175:diagnosis; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D012187:Retroperitoneal Space; D013848:Thigh; D013959:Thyroid Diseases / Q000175:diagnosis