Noninvasive assessment of coronary artery with substantial contrast volume reduction using 320-detector row computed tomography: a feasibility study

The recently introduced 320-detector row computed tomography (320-row CT) allows very fast volumetric acquisition of the entire heart. Because the total amount of contrast agent required for CT coronary angiography (CTCA) depends directly on the acquisition time, 320-row CTCA would substantially reduce the contrast agent dose. The objective of this retrospective study was to evaluate the feasibility of contrast volume reduction on 320-row CTCA compared with 64-detector row CTCA (64-row CTCA). We retrospectively reviewed consecutive 320- and 64-row CTCA data (16 eligible cases for each; administrated contrast volume, 20-24 ml for the former and 50-65 ml for latter) from a homogeneous patient population (age ≤ 81, body weight ≤ 67 kg, and heart rate ≤ 69 bpm). The two types of CTCA data were compared with respect to the successful rate of adequate intravascular contrast enhancement defined as the number of segments with attenuations of more than 250 HU divided by total number of coronary segments evaluated. Our dataset provided mean intravascular attenuation values of 320 and 404 HU on the 320- and 64-row CTCA, respectively. Although the attenuation values were statistically lower for the 320-row CTCA (P < 0.001), there was no significant difference in the successful rates of adequate intravascular contrast enhancement (rate of 0.98 for each; P > 0.05). We therefore conclude that 320-row CTCA is a feasible method of diagnostic imaging and is superior to 64-row CTCA because it uses less of the contrast medium.