Optimized delivery protocol of contrast medium in computed tomography pulmonary angiography with 256-slice spiral CT

Objective To compare the image quality of computed tomography pulmonary angiography(CTPA) required with contrast medium(CM) of different volume and inject-rate using a 256-slice CT scanner and to investigate the optimized delivery protocol of contrast medium in computed tomography pulmonary angiography.Methods 60 patients suspected pulmonary embolism undergoing computed tomography pulmonary angiography were randomly divided into two groups,each containing 30 patients.The volume of contrast medium was 35 ml with the inject-rate 5 ml/s in group A,meanwhile that of group B was 25 ml with the inject-rate 4.5 ml/s.All followed by a saline flush of 30 ml.The CT values of pulmonary arteries,superior vena cava(SVC) and ascending aorta(AA) were compared respectively.Image quality of pulmonary arteries was evaluated.Results There was no statistical significance in the CT values of pulmonary arteries(P0.05),and there was statistical significance in the CT values of superior vena cava(SVC) and ascending aorta(AA) in two groups(P0.05),two groups of pulmonary artery image quality could be diagnostic.Conclusion The use of proper injection-related factors in CTPA,such as a decreased CM volume and a relatively low flow rate can enable pulmonary artery contrast enhancement with a 256-slice CT scanner.