title: Noninvasive assessment of coronary artery bypass graft patency and flow characteristics by electron-beam tomography.
abstract: OBJECTIVE
  To evaluate the flow characteristics and accuracy for the detection of patent or occluded coronary artery bypass grafts (CABG) with multi-slice flow study of electron-beam tomography (EBT).
  
  
  METHODS
  One hundred and twenty-three patients who had undergone CABG surgery were enrolled in this study. Flow datasets were assessed with time-density curves by EBT. The EBT results were blindly compared with post-operative cardiac catheterizations in 26 patients.
  
  
  RESULTS
  Image quality was adequate to evaluate in 111 patients (90.2%). Flow curves of bypass grafts were technically adequate in 265 of 309 (85.8%) saphenous-vein grafts (SVG) and 35 of 56 (62.5%) internal mammary artery (IMA) grafts (p < 0.05). In comparison to conventional angiographic results, EBT correctly identified 14 of 16 occluded grafts (sensitivity, 87.5%) and 68 of 75 patent grafts (specificity, 90.7%), yielding an accuracy of 90.1%. The intra-graft flows of the IMA and SVG were 4.9 +/- 2.2 ml/min/g and 6.9 +/- 2.8 ml/min/g, respectively (p < 0.001), which was 31.6 +/- 20.4% and 39.4 +/- 21.9% of the ascending aorta's flow (16.7 +/- 5.0 ml/min/g) (p < 0.001).
  
  
  CONCLUSIONS
  EBT flow study can be used in the assessment of CABG patency and quantification of intra-graft flow of patent CABG vessels.
authors.affiliation: Department of Radiology, Cardiovascular Institute, Peking Union Medical College, Beijing, China. lubin2001@hotmail.com
authors.forename: Bin
authors.initials: B
authors.lastname: Lu
authors.forename: Ru-Ping
authors.initials: RP
authors.lastname: Dai
authors.forename: Nan
authors.initials: N
authors.lastname: Zhuang
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Budoff
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D001026:Coronary Artery Bypass; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007089:Image Enhancement; D008297:Male; D008323:Mammary Arteries / Q000000981:diagnostic imaging; D008875:Middle Aged; D015588:Observer Variation; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014654:Vascular Patency / Q000502:physiology*