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.