Journal of Cardiovascular Computed Tomography 2015-01-01

Low contrast and radiation dose coronary CT angiography using a 320-row system and a refined contrast injection and timing method.

Seitaro Oda, Daisuke Utsunomiya, Hideaki Yuki, Noriyuki Kai, Masahiro Hatemura, Yoshinori Funama, Masafumi Kidoh, Morikatsu Yoshida, Tomohiro Namimoto, Yasuyuki Yamashita

文献索引：J. Cardiovasc. Comput. Tomogr. 9(1) , 19-27, (2015)

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摘要

Among CT scanners, 320-row instruments feature decreased photon energy and yield strong contrast enhancement. Consequently, the contrast medium (CM) dose can be reduced. The results of low-tube-voltage coronary CT angiography (CCTA) performed on 320-row scanners have not been adequately assessed.We evaluated the effects of a low-contrast-dose protocol on the image quality of CCTA using 80 kVp tube voltage, iterative reconstruction (IR), and a 320-row scanner.We randomly assigned 90 patients (mean body weight, 56.5 ± 11.0 kg) to 1 of 3 CCTA protocols. Under protocol A, 30 were scanned using a conventional 120-kVp protocol and a standard CM dose (280 mg iodine/kg body weight [mgI/kg]). Another 30 underwent scanning at 80 kVp with a 25% CM dose reduction (210 mgI/kg; protocol B). Under protocol C, the remaining 30 patients were scanned at 80 kVp with a 50% CM dose reduction (140 mgI/kg). The 120 and 80 kVp images were processed with IR. Images obtained under the 3 protocols were subjected to quantitative and qualitative analysis.The amount of CM used in protocol A, B, and C was 43.6 ± 10.1, 30.3 ± 4.4, and 21.0 ± 4.0 mL, respectively. Mean CT attenuation of the coronary arteries tended to be higher under protocol B than the other 2 protocols. The contrast-to-noise ratio was significantly higher under protocol B. The mean visual scores were significantly higher for protocols A and B than protocol C. The mean effective radiation dose was significantly lower under the 80-kVp protocol.With a 320-row scanner and our refined CM injection and timing protocol, it is technically feasible to obtain sufficient vascular enhancement with a reduction in the CM and/or radiation dose at 80-kVp CCTA with IR.Copyright © 2015 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.