title: Computed tomographic venography is specific but not sensitive for diagnosis of acute lower-extremity deep venous thrombosis in patients with suspected pulmonary embolus.
abstract: OBJECTIVE
  Duplex ultrasound scanning (US) is the accepted standard means of diagnosis for lower-extremity suprageniculate deep venous thrombosis (LE-DVT). Computed tomographic venography (CTV) has been proposed as an alternative modality for diagnosis of LE-DVT in patients with suspected pulmonary embolism (PE). This study compared CTV with US as a means of diagnosing acute LE-DVT.
  
  
  METHODS
  A retrospective review of US and CTV scans from 136 patients with suspected PE who underwent both studies to exclude acute LE-DVT at a single institution was performed. Studies were reviewed and coded in a blinded manner. US was considered to be the reference test. Direct costs of each study were determined by using commercial software.
  
  
  RESULTS
  The sensitivity and specificity rates of CTV were 71% and 93%, respectively. The positive predictive value, negative predictive value, and accuracy rates of CTV were 53%, 97%, and 90%, respectively. DVT localization was the same in eight of 10 cases in which the results of both US and CTV were positive. CTV costs and charges per study were greater than those of US by $46.88 and $602.00, respectively.
  
  
  CONCLUSIONS
  CTV is specific, but has a lower sensitivity rate and positive predictive value for the diagnosis of acute LE-DVT compared with US. Additionally, CTV is more costly than US scanning. Because of the lower sensitivity rate and positive predictive value and the increased cost of CTV, US remains the screening study of choice in cases of suspected acute LE-DVT.
authors.affiliation: Department of Surgery, University of Michigan Health System, Ann Arbor 48109-0329, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Peterson
authors.forename: E A
authors.initials: EA
authors.lastname: Kazerooni
authors.forename: T W
authors.initials: TW
authors.lastname: Wakefield
authors.forename: B S
authors.initials: BS
authors.lastname: Knipp
authors.forename: A R
authors.initials: AR
authors.lastname: Forauer
authors.forename: B J
authors.initials: BJ
authors.lastname: Bailey
authors.forename: V V
authors.initials: VV
authors.lastname: Sullivan
authors.forename: M C
authors.initials: MC
authors.lastname: Proctor
authors.forename: P K
authors.initials: PK
authors.lastname: Henke
authors.forename: L J
authors.initials: LJ
authors.lastname: Greenfield
authors.forename: J C
authors.initials: JC
authors.lastname: Stanley
authors.forename: G R
authors.initials: GR
authors.lastname: Upchurch
mesh_terms: D003365:Costs and Cost Analysis; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D010690:Phlebography; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000191:economics; D018616:Ultrasonography, Doppler, Duplex / Q000191:economics; D020246:Venous Thrombosis / Q000000981:diagnostic imaging* / Q000453:epidemiology