One hundred thirteen consecutive patients randomly underwent three protocols for dual-phase renal CT angiographic imaging : high-iodine-load ( 600 mg iodine per kilogram of body weight at 120 kVp ) ; moderate-iodine-load ( 400 mg iodine per kilogram of body weight at 80 kVp ) ; and low-iodine-load ( contrast agent injection initially prepared at 400 mg iodine per kilogram of body weight but stopped immediately after bolus-tracking trigger at 80 kVp ) scanning .