下肢动脉血管造影技术对糖尿病足患者末梢动脉准确显示的应用研究

Application of CT angiography in accurate display of peripheral arteries in patients with diabetic foot

目的:探讨下肢动脉CT血管成像(CT angiography,CTA)技术在糖尿病足患者末梢动脉精准显示的优化扫描方案及对图像质量的影响。方法:使用64排CT对75例糖尿病患者行下肢动脉血管造影(CTA),将患者随机分为对照组和优化组。对照组单时相注射对比剂,总碘量=体质量(kg)×450 mg,碘流率=注射总碘量/28/s,locator定位于腹主动脉远端,动脉CT阈值达到300触发扫描,移床准备时间8 s后开始扫描,参数Rotation time 1s,Pitch 0.9。优化组双时相分段连续注射对比剂,第一段注射对比剂碘量=体质量(kg)×450 mg×60%,碘流率=第一次注射碘量/14/s,第二段注射对比剂碘量=体质量(kg)×450 mg×40%,碘流量(流速)=第二次注射碘量/14/s,locator定位于腘动脉,动脉CT阈值达到90触发扫描,参数Rotation time 0.7 s,Pitch 0.9。用EBW后处理工作站处理图像,由一名高年资技师测量下肢血管每节段的CT值,对其结果进行客观评分,由两名中级职称以上的医师对后处理的图像进行主观评分。结果:对照组37例患者图像中26例满足诊断需求,其中11例图像双侧下肢末梢动脉(足背动脉)显示不清,优化组38例患者图像36例满足诊断需求,其中2例图像双侧下肢末梢动脉(足背动脉)显示不清,末梢动脉得分分别为0.910±0.072和0.950±0.050(P<0.05),具有统计学差异,其他区域得分无统计学差异(P>0.005)。远端末梢动脉客观评价得分分别为129.0±27.7和90.0±13.8,髂动脉得分分别为426.0±54.5和392.0±46.2(P<0.05),具有统计学差异,其余区域得分P>0.05,无统计学差异,可见优化组不但可以获得更为丰富的末梢动脉图像,还可以降低近端血管CT值使之获得均一性更佳的血管图像。结论:CTA技术在糖尿病足患者检查中的优化设计,大大提高了糖尿病足这类有血液循环障碍患者的下肢末梢动脉精准显示,末梢动脉显示成功率提高24.4%。在能满足诊断要求的同时,提高了下肢末梢动脉的图像质量,提供了更加真实、丰富的诊断信息,使糖尿病足患者能得到更好的影像医疗服务。

Objective:To investigate the application of CT angiography(CTA)in the optimal scanning scheme for accurate display of peripheral arteries in patients with diabetic foot and its effect on image quality. Methods:A total of 75 patients with diabetes under went CTA of lower extremity arteries with 64-slice CT,and they were randomly divided into control group and optimization group. In the control group,the contrast agent was injected in a single time phase,with total iodine content=body weight(kg)×450 mg and iodine flow rate=total iodine content injected/28/s,and the locator was located at the distal end of the abdominal aorta;the scan was triggered when the CT threshold of the artery reached 300,and the scan was started after preparation for 8 seconds,with Rotation time of 1 s and Pitch of 0.9. In the optimization group,the contrast agent was injected consecutively in two phases,with iodine dose=body weight(kg)×450 mg×60% and iodine flow rate=iodine dose at first injection/14/s for the first phase and iodine dose=body weight(kg)×450 mg ×40% and iodine flow rate =iodine dose at second injection/14/s for the second phase,and the locator was located in the popliteal artery;the scan was triggered when the CT threshold of the artery reached 90,with Rotation time of 0.7 s and Pitch of 0.9.The images were processed by EBW post-processing workstation;a senior technician measured the CT values of each segment of lower extremity blood vessels and determined the objective scores of these results,and two physicians with an intermediate professional title or above determined the subjective score of the post-processing images. Results:Of all 37 patients in the control group,26 had images which met the diagnostic requirements,among whom 11 had unclear display of lower extremity peripheral arteries(dorsal pedal arteries)at both sides. Of all 38 patients in the optimization group,36 had images which met the diagnostic requirements,among whom 2 had unclear display of lower extremity peripheral arteries(dorsal pedal arteries)at both sides. There was a significant difference in the score of peripheral arteries between the two groups(0.910±0.072 vs. 0.950±0.050,P<0.05),while there were no significant differences in the scores of the other regions between the two groups(P>0.005). There were significant differences between the two groups in the objective scores of the distal peripheral arteries(129.0±27.7 vs. 90±13.8,P<0.05)and the iliac artery(426.0±54.5 vs. 392.0±46.2,P<0.05),while there were no significant differences in the scores of the other regions between the two groups(P>0.05),suggesting that the optimization group had more abundant peripheral artery images and lower CT values of proximal vessels to obtain more homogeneous vascular images.Conclusion:CTA for optimal design in the examination of patients with diabetic foot can greatly improve the accuracy of the display of lower extremity peripheral arteries in patients with blood circulation disorders including diabetic foot,and the success rate of the display of peripheral arteries can be increased by 24.4%. CTA can meet the diagnostic requirements,improve the quality of the images of lower extremity arteries,and provide rich information for diagnosis,thus providing better imaging service for patients with diabetic foot.