低剂量直接法CTV对高海拔地区DTV的评价

Evaluation of DTV in high altitude areas based on low dose direct CTV

目的 探讨低剂量直接法下肢静脉CT造影(CTV)诊断高海拔地区下肢深静脉血栓(DVT)的价值,并分析高危致病因素。方法 收集2018年12月-2020年12月来自于高海拔地区(2 562.55±488.93 m)的460例DVT患者,所有患者均行低剂量直接法CTV造影检查,扫描参数:100 kV,自动调制,行iDose4-3处理。直接法:利用Y型管经双侧足背静脉团注300碘普罗胺加生理盐水混合液;结合图像评估并分段下肢深静脉血管;记录低剂量CT检查的容积CT剂量指数(CTDIvol)及剂量长度乘积(DLP)。结果 下肢CTV检查确诊DVT 3 190节段,右侧单发占比41.75%,左侧单发占比44.83%,双侧同时发生占比13.42%。股静脉栓塞发生率较其他部位高,占比19.56%,发生率最低为髂外静脉,占比10.09%;低剂量直接法下肢CTV的辐射剂量,DLP=923.58±257.64 mGy·cm,CTDIvol=8.06±2.28 mGy。结论 低剂量直接法CTV扫描,保证图像质量且降低了辐射剂量,可准确诊断DVT。

Objective To evaluate the value of low dose direct CT venography(CTV) in the diagnosis of lower extremity deep venous thrombosis(DVT) at high altitudes, and to analyze the high-risk factors. Methods 460 patients with DVT from high altitudes(2 562.55 ± 488.93 m) from December 2018 to December 2020 were collected. All patients were examined by low-dose direct CTV. Scanning parameters: 100 kV, automatic modulation, iDose4-3 processing. Direct method: the mixture of 300 iodopropamide and normal saline was injected through bilateral dorsalis pedis vein with Y-tube, the deep veins of lower extremities were evaluated and segmented combined with images, and the volume CT dose index(CTDIvol) and dose length product(DLP)of low dose CT were recorded. Results CTV examination of lower limbs confirmed the diagnosis of DVT3 190 segment. The proportion of single DVT 3 190 on the right side was 41.75%, that of single DVT 3 190 on the left side was 44.83%, and the proportion of simultaneous DVT 3 190 was 13.42%. The incidence of femoral vein embolism was higher than that of other parts(19.56%), and the lowest was external iliac vein(10.09%). The radiation dose of lower extremity CTV by low-dose direct method was 923.58±257.64 mGy·cm for DLP and 8.06 ± 2.28 mGy for CTDIvol. Conclusion Low-dose direct CTV scan can ensure the image quality and reduce the radiation dose, thus being able to accurately diagnose lower extremity deep venous thrombosis.