title: Routine pelvic and lower extremity CT venography in patients undergoing pulmonary CT angiography.
abstract: OBJECTIVE
  The purpose of our study was to assess the utility of performing routine pelvic and lower extremity CT venography (CTV) along with pulmonary CT angiography (CTA) in all patients evaluated for pulmonary embolism.
  
  
  METHODS
  Eight hundred twenty-nine consecutive patients (281 men and 548 women) underwent CTA-CTV for pulmonary embolism. Reports were evaluated as follows: positive or negative for pulmonary embolism with or without deep venous thrombosis (DVT) or with nondiagnostic CTV. Coexisting factors of malignancy, previous venous thromboembolism (VTE), recent surgery, and cardiovascular disease comprised the high-risk group of 446 patients. The remaining 383 patients formed the low-risk group. Statistical analysis included four binary predictors (previous VTE, malignancy, cardiovascular disease, and surgery) and three binary outcome variables (pulmonary embolism, DVT, and VTE). Chi-square test and univariate and multivariate regression analyses were performed.
  
  
  RESULTS
  VTE, pulmonary embolism, and DVT occurred in 152 (18.3%), 124 (15.0%), and 61 (7.3%) of 829 patients, respectively. Between the high-risk and low-risk groups, prevalence of VTE was 114 (25.6%) of 446 and 38 (9.9%) of 383 patients, respectively (p < 0.001); prevalence of pulmonary embolism was 92 (20.6%) of 446 and 32 (8.3%) of 383 patients, respectively (p < 0.001). Isolated DVT was found in 28 (3.4%) of 829 patients. The incremental value of CTV for the entire cohort was 3.4%, 0.72% in the low-risk group (six of 829) and 2.6% (22 of 829) in the high-risk group. For outcome variable VTE, malignancy and previous VTE were statistically significant (p = 0.04 and p < 0.001, respectively); for pulmonary embolism, malignancy and previous VTE were statistically significant (p = 0.03 and p = 0.005, respectively); for DVT, only previous VTE was statistically significant (p < 0.001).
  
  
  CONCLUSIONS
  CTV should not be performed routinely in all patients evaluated for pulmonary embolism and may only be useful in patients with a high probability of pulmonary embolism, including those with a history of VTE and possible malignancy.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, 75 Francis St., Boston, MA 02115, USA.
authors.forename: Andetta R
authors.initials: AR
authors.lastname: Hunsaker
authors.forename: Kelly H
authors.initials: KH
authors.lastname: Zou
authors.forename: Angeline C
authors.initials: AC
authors.lastname: Poh
authors.forename: Beatrice
authors.initials: B
authors.lastname: Trotman-Dickenson
authors.forename: Francine L
authors.initials: FL
authors.lastname: Jacobson
authors.forename: Ritu R
authors.initials: RR
authors.lastname: Gill
authors.forename: Samuel Z
authors.initials: SZ
authors.lastname: Goldhaber
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000000981:diagnostic imaging*; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D010388:Pelvis / Q000000981:diagnostic imaging*; D010690:Phlebography / Q000706:statistics & numerical data*; D015995:Prevalence; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000453:epidemiology; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D020246:Venous Thrombosis / Q000000981:diagnostic imaging* / Q000453:epidemiology