title: Differential CT features of acute lentiform subdural hematoma and epidural hematoma.
abstract: OBJECTIVE
  Acute subdural hematoma (SDH) normally appears as a panhemispheric collection of blood with a crescent configuration. However, a number of SDH show lentiform appearances, mimicking acute epidural hematoma (EDH). In this study, we reported our experiences with this special disease entity. Radiological features that aided in the accurate localization of the hematoma were also addressed.
  
  
  METHODS
  From among 51 acute SDH cases who were surgically treated between July 2007 and April 2008, five cases whose SDH had a localized convex appearance were enrolled. Surgical records and CT images were retrospectively reviewed. Important CT features that could differentiate lentiform SDH from EDH were especially analyzed.
  
  
  RESULTS
  Subdural adhesions were major causes of localized SDH in four out of five patients, all of whom had previous neurosurgical interventions or radiotherapy. Though those hematomas appeared as biconvex on CT scans, four differential features could be identified in favor of SDH. These included a crescentic tail, an obtuse angle at the margin of the hematoma, a dural line above the hematoma and a direct connection to the underlying intracerebral hematomas.
  
  
  CONCLUSIONS
  Biconvex localized SDH might be misinterpreted as acute EDH if the diagnosis is based on the shape of the hematoma alone. This study emphasized that a detailed evaluation of surgical histories and CT features are mandatory in differentiating lentiform SDH and EDH.
authors.affiliation: Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, No. 7 Chung San South Road, Taipei, Taiwan.
authors.forename: I-Chang
authors.initials: IC
authors.lastname: Su
authors.forename: Kuo-Chuan
authors.initials: KC
authors.lastname: Wang
authors.forename: Shih-Hao
authors.initials: SH
authors.lastname: Huang
authors.forename: Chien-Hsun
authors.initials: CH
authors.lastname: Li
authors.forename: Lu-Ting
authors.initials: LT
authors.lastname: Kuo
authors.forename: Jin-Er
authors.initials: JE
authors.lastname: Lee
authors.forename: Ham-Min
authors.initials: HM
authors.lastname: Tseng
authors.forename: Yong-Kwang
authors.initials: YK
authors.lastname: Tu
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D017586:Diskectomy; D005260:Female; D046748:Hematoma, Epidural, Spinal / Q000000981:diagnostic imaging* / Q000601:surgery; D046649:Hematoma, Subdural, Spinal / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D017116:Low Back Pain / Q000601:surgery; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D055815:Young Adult