OBJECTIVE: To assess reduced volumes of contrast agent on image quality for coronary computed tomography angiography (CCTA) by using single-beat cardiac imaging with 320-slice CT.
METHODS: Forty consecutive male patients (mean age: 55.8 years) undergoing CCTA with body weight < 85 kg, heart rate < 65 bpm, and ejection fraction > 55% were included. Image acquisition protocol was standardized (120 kV, 400 mA, and prospective ECG-triggered single-beat nonspiral CCTA). Patients were randomly assigned to one of four groups (G1: received 40 ml, G2: 50 ml, G3: 60 ml, G4: 70 ml). Groups were compared with respect to aortic attenuation, image noise, and image quality.
RESULTS: CT values (mean +/- standard deviation) in the aortic root were measured as 423 +/- 38 HU in G1, and 471 +/- 68, 463 +/- 60, and 476 +/- 78 HU in G2-4, respectively. There were no statistically significant differences in attenuation among the groups (P > 0.068). All 40 CT datasets were rated diagnostic, and image noise and image quality were not statistically different among groups.
CONCLUSIONS: Using 320-slice volume CT, diagnostic image quality can be achieved with 40 ml of contrast material in CCTA in patients with normal body weight, cardiac function, and low heart rate.