title: Power-based colour coded duplex sonography for evaluation of calf veins.
abstract: BACKGROUND
  Power-based colour coded duplex sonography (PD) has been described to display lower flow velocities compared to frequency-based colour coded duplex sonography (CD). This study was undertaken to study the clinical usefulness of PD in the evaluation of calf veins in suspected deep vein thrombosis.
  
  
  METHODS
  
  
  
  METHODS
  A prospective, comparative study.
  
  
  METHODS
  University hospital, Switzerland. PATIENTS AND MEASURES: CD of the complete deep venous system and complementary PD of paired calf veins were performed in 50 consecutive patients with clinically suspected DVT. All except three patients, with failed vein puncture at the dorsum of the foot, had a venography used as reference test for confirmatory diagnosis of DVT.
  
  
  RESULTS
  Complete identification of calf veins increased from 80.5% using CD to 97.9% using complementary PD (p=0.007). Overall accuracy to detect an acute calf DVT was 96% (95% Ci, 85-99%) and 95% (95% CI, 83-99%), respectively. Accuracy was 95% (95% CI, 83-99%) using CD vs 94% (95% CI, 82-98%) using PD in posterior tibial, 87% (95% CI, 74-95%) vs 85% (95% CI, 71-94%) in anterior tibial, and 95% (95% CI, 83-99%) vs 96% (95% CI, 85-99%) in peroneal veins. Chronic post-thrombotic changes (10.6%) were more reliably recognized using CD (accuracy 83% [95% CI, 72-94%]) compared to PD (accuracy 66% [95% CI, 59-85%]) due to tissue motion artifacts and inability to discriminate the direction of blood flow.
  
  
  CONCLUSIONS
  PD used complementary with CD is capable of significantly improving identification of paired calf veins without loss of diagnostic accuracy in the diagnosis of acute DVT.
authors.affiliation: Department of Medicine, University Hospital, Bern, Switzerland.
authors.forename: I
authors.initials: I
authors.lastname: Baumgartner
authors.forename: M
authors.initials: M
authors.lastname: Braunschweig
authors.forename: J
authors.initials: J
authors.lastname: Triller
authors.forename: F
authors.initials: F
authors.lastname: Mahler
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D012680:Sensitivity and Specificity; D013924:Thrombophlebitis / Q000000981:diagnostic imaging*; D018615:Ultrasonography, Doppler, Color / Q000379:methods