Clinical Studies Of Multislice Spiral Ct Pulmonary Angiography In The Joint Of Lower Extremity Venous Angiography In The Diagnosis Of Pulmonary Embolism And Deep Vein Thrombosis

Objective: To evaluate the enhancement degree of lower extremity deep veinsand pulmonary arteries by using lesser contrast material and a biphasic injection protocol in the examination of combined CT venography and pulmonary angiography(CTVPA), and to establish a routine scan protocol. Materials and methods:From Aug 2002 to Mar 2004, 50 CTVPA examinations were done in 48 patients of clinically suspected pulmonary embolism. 20 examinations (group 1) were performed by using 150ml contrast material (300mg I/ml) with a flow rate of 4ml/s. The other 30 examinations (group 2) were performed by using 120ml contrast material with biphasic injection protocol: first phase, 50ml with a flow rate of 4ml/s; second phase, 70ml with a flow rate of 2ml/s. Attenuation values for each examination were measured in the inferior vena cava, bilateral common iliac vein, external iliac vein, internal iliac vein, common femoral vein, superficial femoral vein, deep femoral vein and popliteal vein on the CT venography. The attenuation values in the pulmonary trunk, apical segmental arteries of the bilateral upper lobes, posterior segmental arteries of the bilateral lower lobes and ascending aorta were also measured at the same time. The artifacts in the superior vena cava were scored as follows: 0 point, the artifacts were not exist; 1 point, a little artifacts exist; 2 points, significant artifacts exist and affect the demonstration of right pulmonary artery and right upper lobepulmonary artery. Results: Very good enhancement was obtained in veinsmentioned above in both groups with mean attenuation values of 98~ 117HU without significant difference (P>0.05). High degree enhancement was also obtained in pulmonary arteries in both groups with mean attenuation of 323~420HU, which was...