Takeshi Nakaura MD, Presenter: Nothing to Disclose

Kazuo Awai MD, Abstract Co-Author: Nothing to Disclose

Yumi Yanaga MD, Abstract Co-Author: Nothing to Disclose

Yasuhiro Nagayoshi, Abstract Co-Author: Nothing to Disclose

Masahiro Hatemura, Abstract Co-Author: Nothing to Disclose

Yasuyuki Yamashita MD, Abstract Co-Author: Nothing to Disclose

Hisao Ogawa, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Even with identical contrast-injection protocols, coronary artery enhancement differs among patients due to factors such as the circulating blood volume, cardiac output, and vascular resistance. We developed a new individually customized contrast injection protocol for coronary CT angiography (c-CTA) that is 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 (Brilliance-64, Philips). They were randomly assigned to one of two protocols. In protocol 1 (P1) we estimated the minimal contrast dose to yield peak aortic enhancement of 400 HU based on the deconvolution-of-time-attenuation response to a small test-bolus injection (0.3 mL/body weight [kg]) delivered over 9 sec. Then we administered a customized contrast dose over 9 sec for c-CTA. In protocol 2 (P2) the dose was tailored to the patient BW; this group received 0.7 ml/kg BW at an injection duration of 9 sec. We compared the 2 protocols for the contrast medium (CM) dose, peak attenuation, and variations in the attenuation values of the ascending aorta.

The contrast dose was significantly smaller in P1 than P2 (36.9 ± 9.2 mL vs. 43.1±7.0 mL , por= 320 HU) was obtained in all P1 patients.

At c-CTA using 64-detector CT, the test-injection-response-adjusted protocol(P1) facilitated a reduction in the contrast dose, reduced the individual variations in vessel enhancement compared to P2, and yielded sufficient vessel enhancement.

The test-injection-response-adjusted protocol makes it possible to reduce the contrast dose, reduced variations in vessel enhancement, and yields sufficient vessel enhancement for c-CTA on a 64-detect

Nakaura, T, Awai, K, Yanaga, Y, Nagayoshi, Y, Hatemura, M, Yamashita, Y, Ogawa, H, et al, , et al, , Novel Contrast-injection Protocol for Coronary CT Angiography at 64-detector CT: Contrast-Injection Protocol Customized According to the Patient Time-Attenuation-Response.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5008549.html