Optimizing contrast media application in coronary CT angiography at lower tube voltage: Evaluation in a circulation phantom and sixty patients

Purpose: The purpose was to investigate optimal contrast media (CM) injection parameters for lower kVp settings, whilst maintaining diagnostic attenuation levels. Methods and materials: First, a circulation phantom with physiological parameters (BP 120/80 mmHg, HR 60 bpm) was used. A fixed CM injection protocol was used for each kVp setting (300 mgI/m1 [Iopromide], volume =45 ml, flow rate = 6.0 ml/s, iodine delivery rate [IDR] = 1.8 gI/s, iodine load = 13.5 gI; at 120, 100, 80 and 70 kVp). Then, IDR was decreased by steps of 0.2 gI/s for each kVp setting, until diagnostically insufficient attenuation values were reached (