High opacification of hilar pulmonary vessels with a small amount of nonionic contrast medium for general thoracic CT: a prospective study.

Abstract

The main goal of this study was to determine whether in thoracic helical CT for general indications a high opacification of hilar pulmonary vessels could be obtained using a small amount of nonionic contrast medium. Two hundred consecutive patients referred for contrast-enhanced thoracic CT for malignancies or infections prospectively entered the study. They were randomly assigned to one of two simple bolus injection protocols (100 patients in each protocol): 60 mL of a nonionic contrast agent (250 mg I/mL) injected at a 3 mL/sec flow rate, or 80 mL of the same contrast agent injected at a 4 mL/sec flow rate. No saline flush or bolus triggering system was used. Hilar and mediastinal vessel enhancement was qualitatively (using a 4-point scale) and quantitatively (arterial attenuation values) assessed. Perivenous artifacts were also assessed. No extensive perivenous artifacts were noted. No significant difference was noted regarding pulmonary venous enhancement. Excellent opacification of the pulmonary veins was observed in 66% of patients injected at 3 mL/sec and in 56% of patients injected at 4 mL/sec (p > 0.192). A highly significant difference was noted for pulmonary artery enhancement. Excellent opacification of the pulmonary arteries was noted in 83% of patients injected with a 3mL/sec flow rate and in 61% of patients injected with a 4 mL/sec flow rate (p = 0.001). A high level of opacification of hilar pulmonary vessels, with no major perivenous artifacts, can be obtained with a small amount of nonionic contrast medium using a simple bolus injection.