title: Reduction of interpatient variability of arterial enhancement using a new bolus tracking system in 320-detector computed tomographic coronary angiography.
abstract: OBJECTIVE
  To investigate the effect of a new bolus tracking system on interpatient variability of aortic and coronary enhancement compared with the conventional system in 320-detector computed tomographic (CT) coronary angiography (CTCA).
  
  
  METHODS
  Sixty-four patients who underwent CTCA were assigned to 1 of 2 protocols. In group A (n = 32), 7 seconds after triggering (150-Hounsfield unit [HU] threshold) in the ascending aorta, a CT scan was performed. In group B (n = 32), 2 thresholds were set in the ascending aorta. After the first triggering (100 HU threshold), the patient was instructed to take a breath and hold it. Approximately 3 seconds after the second triggering (300 HU threshold), a CT scan was started automatically.
  
  
  RESULTS
  There were no significant differences in the mean CT attenuation for the ascending aorta between the 2 groups (P = 0.61), whereas the standard deviation of the CT attenuation in group B was significantly smaller than that in group A (P = 0.02).
  
  
  CONCLUSIONS
  The use of a 2-threshold setting in the new bolus tracking technique could reduce interpatient variability more than a protocol using a single threshold in CTCA.
authors: Department of Diagnostic Radiology, Hiroshima University, 1-2-3 Kasumi, Hiroshima, Japan. sa104@rg8.so-net.ne.jp
authors: Fuminari
authors: F
authors: Tatsugami
authors: Kazuo
authors: K
authors: Awai
authors: Haruhiko
authors: H
authors: Takada
authors: Shushi
authors: S
authors: Yoshikawa
authors: Yoshihiro
authors: Y
authors: Takeda
authors: Hideaki
authors: H
authors: Morita
authors: Yoshifumi
authors: Y
authors: Narumi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001027:Aortography / Q000379:methods*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol