Dual flow 기법을 이용한 Triphasic injection의 유용성

Usefulness of Triphasic injection with Dualflow technique

Purpose To evaluate the artifacts of subclavian vein and thoracic vessel enhancement using dualflow of contrast media and normal saline. Materials and Methods 40 patients with chest disease undeiwent routine chest CT on a 16 detector-row CT scanner(Somatom Sensation 16; Siemens Medicl Solution). Patients were randomly assigned to one of two injection protocols. Twenty(20) patients were scanned with a biphasic protocol(iodine bolus followed by a saline chaser) using a dual-syringe injector(Stellant: Medrad), twenty(20) patients with a triphasic protocol with dualflow techniqe with simultaneous injection from two syringes to achieve a desired mixing ratio of contrast media and normal saline. The iodine bolus was followed by a 50:50 saline/contrast(ultravist 370, Schering) ratio and a saline chaser. Estimation of subclavian vein artifacts and thoracic vessel enhancement was performed base on the CT number of both protocol. Results The average density of subclavian vein was significant lower with a triphasic injection protocol than the biphasic protocol( 950± 242HU vs 1204± 280HU). The average estimated thoracic vessel enhancement was a little higher with a triphasic injection protocol. ; Ascending aorta: 323± 40HU vs 303± 31HU ; Pulmonary trunk: 286± 37HU vs 263± 45HU ; Descending aorta: 327± 42HU vs 305± 29HU Conclusion In comparison with a saline chaser after contrast bolus, dualflow injection provide more higher enhancement for thoracic vessel while generally avoiding subclavian vein artifacts from dense contrast material. Thus, for chest CT for the better image quality, the triphasic injection with dualflow technique is recommended.