Rationale and objectives: This study was designed to determine the optimal contrast protocol for 4-detector-row computed tomography angiography of the heart.
Methods: Sixty patients were randomly assigned to 1 of 4 groups with 300 and 400 mg/mL iodine concentrations and 2.5 and 3.5 mL/s flow rates. Contrast density was measured in the left ventricular cavity and coronary arteries.
Results: Low iodine concentration injected at slow flow rate (0.75 g iodine/s) resulted in acceptable contrast enhancement in only 53.8% of the patients. There was no significant difference between low contrast concentration injected at high flow rate and high contrast concentration injected at slow flow rate ( approximately 1 g iodine/s). High contrast concentration administered with high flow rates (1.4 g iodine/s) may result in an enhancement above 350 Hounsfield units (HU) and interfere with coronary calcifications.
Conclusions: The injection of approximately 1 g iodine/s resulted in an optimal (250-300 HU) contrast enhancement for cardiac 4-detector-row computed tomography.