title: Low-dose contrast protocol using the test bolus technique for 64-detector computed tomography coronary angiography.
abstract: OBJECTIVE
  We evaluated low-contrast injection protocols for coronary computed tomography angiography (CTA) using a 64-detector scanner and the test bolus technique.
  
  
  METHODS
  We randomly assigned 60 patients undergoing coronary CTA to one of two contrast material (CM) injection protocols. For the low-contrast dose protocol (P(low)), the patients received injections of iohexol-350 [0.7 ml/kg body weight (BW)] during 9 s, and the test-bolus technique was used. Under the conventional protocol (P(conv)), they received iohexol-350 (1.0 ml/kg BW) during 15 s, and bolus tracking was used. We compared the protocols for attenuation values in the ascending aorta and coronary arteries and for the amount of CM required.
  
  
  RESULTS
  There was no significant difference in the mean CT attenuation of the ascending aorta and coronary arteries between the P(low) and P(conv) groups. The amount of CM was significantly less with P(low) than with P(conv) [49.7 ± 6.4 ml (main bolus: 39.7 ± 6.4 ml) vs. 57.0 ± 10.1 ml, P < 0.01].
  
  
  CONCLUSIONS
  With 64-detector CTA of the heart, the low-dose and short-injection-duration protocol with the test-injection technique provides vessel attenuation comparable to that obtained with the standard-dose protocol with the bolus-tracking technique.
authors: Department of Diagnostic Radiology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan. kff00712@nifty.com
authors: Takeshi
authors: T
authors: Nakaura
authors: Kazuo
authors: K
authors: Awai
authors: Yumi
authors: Y
authors: Yanaga
authors: Tomohiro
authors: T
authors: Namimoto
authors: Daisuke
authors: D
authors: Utsunomiya
authors: Toshinori
authors: T
authors: Hirai
authors: Seigo
authors: S
authors: Sugiyama
authors: Hisao
authors: H
authors: Ogawa
authors: Masahito
authors: M
authors: Aoyama
authors: Yasuyuki
authors: Y
authors: Yamashita
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods; D016009:Chi-Square Distribution; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol