能谱CT一次性成像技术在肺动脉及下肢静脉造影中的应用研究

Application study of the energy spectrum CT one-step imaging in evaluating lower vein and pulmonary angiography

目的 探讨宝石能谱CT一次性成像扫描技术在肺动脉造影(CTPA)和间接下肢静脉造影(CTV)中的应用价值.方法 对43例临床怀疑肺栓塞(PE)及下肢静脉血栓(DVT)患者,先行CTPA扫描,再对髂静脉使用二次监测技术,分段注射对比剂一次性完成CTPA和间接CTV.后处理用GSI扫描数据获取静脉血管与肌肉间最佳对比噪声比(CNR)对应的单能量图像,设定筛选能量为40～ 90 keV图像进行轴位观察.结果 混合能量显示DVT 28例,其中合并PE 18例;GSI最佳单能量图像显示DVT 30例,其中合并PE 21例.下肢静脉血管与肌肉间的最佳对比噪声比(CNR)在40～65 keV,平均(47±6)keV.结论 通过使用二次监测技术对患者下肢静脉进行个体化延迟扫描,联合最佳单能量图像增加组织对比,可以提高静脉血栓栓塞病灶的检出率.

Objective To discuss the value of the one-step gemstone spectral CT imaging(GSI) in pulmonary angiography(CTPA) and indirect lower extremity venous angiography(CTV). Methods 43 suspected pulmonary embolism and deep vein thromboembolism(DVT) patients were performed both CTPA and indirect lower extremity CTV using secondary SmartPrep technique and segmented injection of contrast agent. The CNR between veins and muscles were measured. Screening of energy 40-90 keV were selected to observed axial images. Results A total of 43 cases,28 cases with DVT(18 cases combined with pulmonary embolism) were detected on QC image. 30 cases with DVT(21 cases combined with pulmonary embolism) were detected on the optimized mono energy of Gemstone spectra image. The optimal contrast-to-noise(CNR) radio between deep veins of lower extremities and muscular tissue was 45keV to 65 keV(mean 47 ± 6 keV). Conclusion GSI optimized monochromatic imaging can improve the detection rate of venous thromboembolism lesions. Using secondary SmartPrep technique and individualized selecting lower limb venous delayed scan time can ensure the quality of image.