title: Intraabdominal hematoma: the concentric-ring sign in MR imaging.
abstract: Extracranial hematomas have variable CT appearances and may be confused with other entities. MR imaging of 12 patients with intraabdominal or intrapelvic hemorrhages showed that intraabdominal hematomas develop a unique MR appearance after 3 weeks. Nine hematomas imaged after this time all showed a characteristic concentric-ring configuration, with a thin, dark peripheral rim on all pulse sequences and a bright inner ring most distinctive on T1-weighted images. Six hematomas imaged during the first 3 weeks failed to show this architecture. The concentric rings in MR images of chronic hematomas allowed a tissue-specific diagnosis.
mesh_terms: D000009:Abdominal Muscles / Q000473:pathology; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis*; D006406:Hematoma / Q000175:diagnosis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D010388:Pelvis / Q000473:pathology