title: Extrapleural hematomas: imaging appearance, classification, and clinical significance.
abstract: OBJECTIVE
  We sought to identify radiologic and clinical findings associated with extrapleural hematomas (EPHs), to formulate an imaging-based classification system for EPHs, and to identify any radiologic or clinical factors associated with surgical intervention.
  
  
  METHODS
  Thirteen cases of EPH were gathered during the clinical review. An EPH was diagnosed on computed tomography (CT) if there was inward displacement of extrapleural fat by an intrathoracic peripheral fluid collection. The location and shape of each EPH were documented. For each case, the chest radiograph obtained in closest proximity to the CT acquisitions was also reviewed. The following additional data were also gathered: coexistent thoracic and nonthoracic injuries; mechanism of injury; treatment; and outcome.
  
  
  RESULTS
  In our series, 92% of the patients (12/13) were male. The average age of the affected patients was 61 years. Most cases were related to blunt trauma (85%, 11/13). All these patients had additional injuries; rib fractures were most consistently present (81%, 9/11). All cases could be further categorized based on the appearance of their CT scan as biconvex or nonconvex. Biconvex EPHs tended to be larger than other types (average size of 4211 mL) and required surgical intervention in 80% of patients (4/5). No specific treatment was necessary in patients with nonconvex EPHs.
  
  
  CONCLUSIONS
  EPHs occur most commonly in high-energy blunt trauma; concomitant injuries are the rule, especially rib fractures. Biconvex hematomas tend to be large, likely resulting from high-pressure bleeding. Consequently, biconvex EPHs more often require surgical intervention. Nonconvex hematomas can usually be managed conservatively.
authors.affiliation: Department of Radiology, University of Washington Hospitals, Seattle, WA, USA. jonherochung@yahoo.com
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Chung
authors.forename: Robert B
authors.initials: RB
authors.lastname: Carr
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Stern
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006406:Hematoma / Q000145:classification / Q000175:diagnosis* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed