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

Abstract:

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 underwent 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 optimiza－tion group，36 had images which met the diagnostic require－ments，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 pe－ripheral 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 dis－play 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.