title: Detection of venous emboli using Doppler ultrasound.
abstract: OBJECTIVE
  To detect emboli in the venous system using a Doppler ultrasound device with embolism detecting software.
  
  
  METHODS
  Pulmonary embolism (PE) was induced by injecting thrombus through the iliac vein of castrated swine under general anaesthesia. Data recorded from the Doppler system were analysed for high intensity transient signals (HITS) using receiver operating characteristic curves. Four different thrombi (5 or 10mm long and 3 or 5mm in diameter) were then injected to assess the quantitative analysis.
  
  
  RESULTS
  Thrombus could be detected in the venous system by the Doppler ultrasound device with an embolism detecting function. Appropriate confidence level was 60%. If thrombus were assumed to travel at the maximum flow rate (30 cm/s) in the inferior vena cava, the estimated embolism size was 10.4 S.D. 2.8mm for 3mm and 10.8 S.D. 4.9 mm for 5mm, both of which were close to 10mm.
  
  
  CONCLUSIONS
  Thrombi could be detected as high intensity transient signals in the venous system. The appropriate confidence level was 60%. The size of emboli can be estimated if they are more than 3mm in diameter when the venous flow rate is 30 cm/s or less. Our results suggest that it may be possible to detect emboli in the subclavian vein, axillary vein or inferior vena cava in clinical cases.
authors.affiliation: Department of Vascular and Applied Surgery, Tokyo Medical and Dental University Graduate School, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
authors.forename: T
authors.initials: T
authors.lastname: Kudo
authors.forename: N
authors.initials: N
authors.lastname: Kurihara
authors.forename: N
authors.initials: N
authors.lastname: Sugano
authors.forename: T
authors.initials: T
authors.lastname: Iwai
mesh_terms: D000818:Animals; D001367:Axillary Vein / Q000000981:diagnostic imaging; D001783:Blood Flow Velocity; D004195:Disease Models, Animal; D008297:Male; D011237:Predictive Value of Tests; D011651:Pulmonary Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013350:Subclavian Vein / Q000000981:diagnostic imaging; D013552:Swine; D018616:Ultrasonography, Doppler, Duplex; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging* / Q000503:physiopathology; D020246:Venous Thrombosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology