title: Novel contrast-injection protocol for coronary computed tomographic angiography: contrast-injection protocol customized according to the patient's time-attenuation response.
abstract: We developed a new individually customized contrast-injection protocol for coronary computed tomography (CT) angiography based on the time-attenuation response in a test bolus, and investigated its clinical applicability. We scanned 60 patients with suspected coronary diseases using a 64-detector CT scanner, who were randomly assigned to one of two protocols. In protocol 1 (P1), we estimated the contrast dose to yield a peak aortic attenuation of 400 HU based on the time-attenuation response to a small test-bolus injection (0.3 ml/kg body weight) delivered over 9 s. Then we administered a customized contrast dose over 9 s. In protocol 2 (P2), the dose was tailored to the patient's body weight; this group received 0.7 ml/kg body weight with an injection duration of 9 s. We compared the two protocols for dose of contrast medium, peak attenuation, variations in attenuation values of the ascending aorta, and the success rate of adequate attenuation (250-350 HU) of the coronary arteries. The contrast dose was significantly smaller in P1 than in P2 (36.9 ± 9.2 vs 43.1 ± 7.0 ml, P < 0.01). Peak aortic attenuation was significantly less under P1 than under P2 (384.1 ± 25.0 vs 413.5 ± 45.7, P < 0.01). The mean variation (standard deviation) of the attenuation values was smaller in P1 than in P2 (25.0 vs 45.7, P < 0.01). The success rate of adequate attenuation of the coronary arteries was significantly higher with P1 than with P2 (85.0 vs 65.8 %, P < 0.01). P1 facilitated a reduction in the contrast dose, reduced the individual variations in peak aortic attenuation, and achieved optimal coronary CT attenuation (250-350 HU) more frequently than P2.
authors.affiliation: Diagnostic Radiology, Amakusa Medical Center, Kameba 854-1, Amakusa, Kumamoto, 863-0046, Japan, masafkidoh@yahoo.co.jp.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kidoh
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakaura
authors.forename: Shinichi
authors.initials: S
authors.lastname: Nakamura
authors.forename: Kazuo
authors.initials: K
authors.lastname: Awai
authors.forename: Daisuke
authors.initials: D
authors.lastname: Utsunomiya
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Namimoto
authors.forename: Kazunori
authors.initials: K
authors.lastname: Harada
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007472:Iohexol / Q000008:administration & dosage*; D007564:Japan; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies
chemical_list: D003287:Contrast Media; D007472:Iohexol