ABSTRACT
Objective:To explore the clinical value of one-step CT angiography from deep vein of lower limbs to pulmonary artery in the direction of head and foot.Methods:Twenty-eight patients who presented Haikou Affiliated Hospital of Central South University Xiangya School of Medicine from January 2017 to June 2019 were collected. All patients who underwent one-step CT angiography of the deep veins of the lower extremities to the pulmonary artery were randomly divided into two groups, A or B, and scanned from the entrance of the thorax to 10 cm below the knee joint. Group A was foot-head direction group with delayed time scanning according to empirical method. Group B was the head-foot direction group with a single point triggered automatic tracing scan at the level of the main pulmonary artery trunk. The independent sample t-test was used to compare the scan time, dose length product (DLP), and mean CT value of enhancement of the pulmonary artery opening between the two groups. Results:The average scanning time of the foot-head scanning group was (36.4±1.2)s, the average DLP was (684.4±37.8) mGy·cm, and the average enhanced CT value of pulmonary artery image was (181.3±15.5) HU. The average scanning time of the head foot scanning group was (16.4±0.3) s, the average DLP was (441.8±34.4) mGy·cm, and the average enhanced CT value of the pulmonary artery image was (257.9±24.5) HU. Scanning time, mean DLP, and pulmonary artery level enhancement values were significantly different between the two groups ( t=17.92, 4.71, 2.44, P<0.05). Conclusions:The clinical value of one-step CT angiography from deep vein of lower limbs to pulmonary artery in the head-foot direction is significantly better than that in the head-foot direction. It can significantly shorten the scanning time, reduce the radiation dose, and increase the enhancement value of pulmonary artery to improve the detection of pulmonary embolism.