[Multislice CT of the thorax: effects of contrast material pushed with saline solution using a dual power injector on contrast material dose and perivenous artifacts].

A new method of power injection of contrast material flushed with saline solution for thoracic multislice CT using a dual power injector was evaluated in 105 patients. The patients were categorized into 3 groups of 35 patients each, according to the protocol of contrast material administration: (1) 100 mL of non-ionic contrast material(300 mgI/mL), (2) 75 mL of the same contrast material, and (3) 75 mL of the same contrast material flushed with 30 mL of saline solution. Scanning was performed in a caudal-to-cranial direction. Mean attenuation for the three protocols was measured in the superior vena cava, pulmonary trunk, ascending aorta, and descending aorta. Vascular opacification and perivenous artifacts were graded using four-point scoring by a consensus panel of three blinded radiologists. Intravenous injection of 75 mL of contrast material flushed with saline solution provided significantly better vascular opacification in the superior vena cava(p < 0.001) and pulmonary trunk(p < 0.02) than that provided by a 75 mL or 100 mL injection of contrast material alone. A similar degree of enhancement was observed in the ascending and descending aorta. Further, perivenous artifacts in the subclavian vein were significantly reduced (p < 0.05).