Body size-adapted dose of contrast material and scanning protocol in 320-detector row CT coronary angiography.

OBJECTIVE: Because an increase in patient body size produces lower vessel attenuation and higher image noise in computed tomography coronary angiography (CTCA), a protocol in which the dose of contrast material was adapted to the body weight, and tube voltage and current were adapted to the body mass index (BMI) was evaluated. METHODS: A total of 136 patients who underwent CTCA were assigned to 1 of 2 protocols; the patients received 40 mL of contrast material (A; n = 52), or 0.7 mL/kg of contrast material (B; n = 84). Tube voltage and current were adapted to the BMI. RESULTS: In group A, there was no significant correlation between BMI and image noise (r = -0.21, P = 0.15). However, BMI correlated inversely with contrast-to-noise ratio (CNR; right coronary artery, r = -0.29, P < 0.05; left main coronary artery, r = -0.33, P < 0.05) and image quality score (r = -0.55, P < 0.001). In group B, there was no significant correlation between BMI and image noise (r = -0.14, P = 0.21), CNR (right coronary artery: r = -0.09, P = 0.45; left main coronary artery: r = -0.07, P = 0.55), and image quality score (r = 0.03, P = 0.79). CONCLUSIONS: Use of a body size-adapted dose of contrast material and scanning protocol results in similar CNR and image quality independent of individual BMI.

Feasibility of low-volume injections of contrast material with a body weight-adapted iodine-dose protocol in 320-detector row coronary CT angiography.

RATIONALE AND OBJECTIVES: To investigate the feasibility of low-volume injections of contrast material with a body weight-adapted iodine-dose protocol in computed tomography coronary angiography (CTCA) using a 320-detector row scanner. MATERIALS AND METHODS: Ninety-eight patients who underwent CTCA in a single heartbeat with electrocardiogram-gating were divided into two groups, receiving 0.8 mL/kg of contrast material injected at a fixed duration of 12 seconds (A; n = 48) or 0.7 mL/kg of contrast material injected at a fixed duration of 10 seconds (B; n = 50); all patients then received 20 mL of saline. Contrast densities were assessed for the ascending aorta, left ventricle, right coronary artery (RCA), and left main coronary artery (LMA). RESULTS: The mean flow rate was 4.00 + or - 0.56 mL/second in group A and 4.06 + or - 0.57 mL/second in group B (P = .51). There were no significant differences in the mean enhancement values of the ascending aorta, LMA and proximal RCA between the two groups. Also, there was no significant difference between the mean enhancement values at the three different levels of the RCA (proximal, middle, and distal segments) (group A; P = .27, group B; P = .07). CONCLUSION: The use of 0.7 mL/kg of contrast material injected at a fixed duration of 10 seconds was feasible for CTCA using 320-detector row CT, with a sufficient and reliable contrast enhancement in the ascending aorta and coronary artery.