title: Benign anterior temporal epidural hematoma: indolent lesion with a characteristic CT imaging appearance after blunt head trauma.
abstract: OBJECTIVE
  To study the incidence, pathogenesis, imaging characteristics, and clinical importance of a unique subtype of epidural hematoma (EDH) associated with blunt head trauma.
  
  
  METHODS
  This study was reviewed and approved by the hospital's Institutional Review Board and was compliant with HIPAA. Informed consent was waived. The investigation was a retrospective study of 200 patients with acute supratentorial EDH, defined as a biconvex, high-attenuating, extraaxial hematoma. A subgroup of 21 patients in whom the EDH was located at the anterior aspect of the middle cranial fossa was defined. Computed tomographic images and inpatient medical records of these 21 patients were evaluated for imaging characteristics of the EDH, presence or absence of associated fracture, presence or absence of midline shift and/or mass effect, additional intracranial injury, and hospital clinical course.
  
  
  RESULTS
  Twenty-one (10.5%) of 200 traumatic EDHs localized to the anterior middle cranial fossa. All of these 21 anterior temporal EDHs were juxtaposed to the sphenoparietal sinus, and all but one were limited laterally by the sphenotemporal suture and medially by the orbital fissure; none extended above the lesser sphenoid wing. Maximum thickness was less than 1 cm in 13 (62%) of 21 and less than 2 cm in 20 (95%) of 21 patients. Isolated fractures of the greater sphenoid wing and ipsilateral zygomaticomaxillary fractures were present in 12 (57%) of 21 and nine (43%) of 21 patients, respectively. Concomitant intracranial injury was identified in 15 (71%) of 21 patients. Twenty (95%) of 21 lesions were present at the admission study, and all 21 were stable or smaller at follow-up imaging. No patient required neurosurgical intervention of their anterior temporal EDH.
  
  
  CONCLUSIONS
  Acute EDHs isolated to the anterior aspect of the middle cranial fossa constitute a subgroup of traumatic EDHs with a benign natural history. It is postulated that they arise from venous bleeding due to disruption of the sphenoparietal sinus.
authors: Department of Radiology, University of California, San Francisco, San Francisco, Calif, USA. agean@sfghrad.ucsf.edu
authors: Alisa D
authors: AD
authors: Gean
authors: Nancy J
authors: NJ
authors: Fischbein
authors: Derk D
authors: DD
authors: Purcell
authors: Ashley H
authors: AH
authors: Aiken
authors: Geoffrey T
authors: GT
authors: Manley
authors: Shirley I
authors: SI
authors: Stiver
mesh_terms: D000293:Adolescent; D000328:Adult; D006259:Craniocerebral Trauma / Q000150:complications / Q000000981:diagnostic imaging*; D005260:Female; D006407:Hematoma, Epidural, Cranial / Q000000981:diagnostic imaging* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D014949:Wounds, Nonpenetrating / Q000150:complications / Q000000981:diagnostic imaging*