Low-dose contrast protocol using the test bolus technique for 64-detector computed tomography coronary angiography
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We evaluated low-contrast injection protocols for coronary computed tomography angiography (CTA) using a 64-detector scanner and the test bolus technique.
Materials and methods
We randomly assigned 60 patients undergoing coronary CTA to one of two contrast material (CM) injection protocols. For the lowcontrast dose protocol (Plow), 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 (Pconv), 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.
There was no significant difference in the mean CT attenuation of the ascending aorta and coronary arteries between the Plow and Pconv groups. The amount of CM was significantly less with Plow than with Pconv [49.7 ± 6.4 ml (main bolus: 39.7 ± 6.4 ml) vs. 57.0 ± 10.1 ml, P < 0.01].
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.
Key wordsComputed tomography Contrast injection protocol Cardiac Test bolus Bolus tracking
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