title: Venous thromboembolism: additional diagnostic value and radiation dose of pelvic CT venography in patients with suspected pulmonary embolism.
abstract: OBJECTIVE
  To assess the additional diagnostic value of indirect CT venography (CTV) of the pelvis and upper thighs performed after pulmonary CT angiography (CTA) for the diagnosis of venous thromboembolism (VTE).
  
  
  METHODS
  In a retrospective analysis, the radiology information system entries between January 2003 and December 2007 were searched for patients who received pulmonary CTA and additional CTV of the pelvis and upper thighs. Of those patients, the radiology reports were reviewed for the diagnosis of pulmonary embolism (PE) and deep venous thrombosis (DVT) in the pelvic veins and veins of the upper thighs. In cases with an isolated pelvic thrombosis at CTV (i.e. which only had a thrombosis in the pelvic veins but not in the veins of the upper thigh) ultrasound reports were reviewed for the presence of DVT of the legs. The estimated radiation dose was calculated for pulmonary CTA and for CTV of the pelvis.
  
  
  RESULTS
  In the defined period 3670 patients were referred to our institution for exclusion of PE. Of those, 642 patients (353 men, 289 women; mean age, 65±15 years, age range 18-98 years) underwent combined pulmonary CTA and CTV. Among them, PE was found in 227 patients (35.4%). In patients without PE CTV was negative in all cases. In patients with PE, CTV demonstrated pelvic thrombosis in 24 patients (3.7%) and thrombosis of the upper thighs in 43 patients (6.6%). Of those patients 14 (2.1%) had DVT in the pelvis and upper thighs. In 10 patients (1.5%) CTV showed an isolated pelvic thrombosis. Of those patients ultrasound reports were available in 7 patients, which revealed DVT of the leg veins in 5 cases (1%). Thus, the estimated prevalence of isolated pelvic thrombosis detected only by pelvic CTV ranges between 1-5/642 patients (0.1-0.7%). Radiation dose ranges between 4.8 and 9.7 mSv for additional CTV of the pelvis.
  
  
  CONCLUSIONS
  CTV of the pelvis performed after pulmonary CTA is of neglectable additional diagnostic value for the detection of VTE, because the additional radiation dose is high and isolated pelvic DVT is very rare. Venous imaging of the legs (preferably by radiation-free ultrasound) is sufficient for the diagnosis of underlying DVT in patients with suspected PE.
authors.affiliation: Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany. Miriam.Reichert@umm.de
authors.forename: Miriam
authors.initials: M
authors.lastname: Reichert
authors.forename: Thomas
authors.initials: T
authors.lastname: Henzler
authors.forename: Radko
authors.initials: R
authors.lastname: Krissak
authors.forename: Paul
authors.initials: P
authors.lastname: Apfaltrer
authors.forename: Kurt
authors.initials: K
authors.lastname: Huck
authors.forename: Karen
authors.initials: K
authors.lastname: Buesing
authors.forename: Tim
authors.initials: T
authors.lastname: Sueselbeck
authors.forename: Stefan O
authors.initials: SO
authors.lastname: Schoenberg
authors.forename: Christian
authors.initials: C
authors.lastname: Fink
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010388:Pelvis / Q000000981:diagnostic imaging*; D010690:Phlebography; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed; D054556:Venous Thromboembolism / Q000000981:diagnostic imaging*; D055815:Young Adult