64层螺旋CT上肢动脉成像技术研究

目的前瞻性研究64层CT上肢动脉成像方法和临床价值,寻找最佳的对比剂注射方式、速度、用量及最佳的扫描、后处理参数。方法用64层螺旋CT对疑诊上肢动脉病变的48例病人应用不同准直、螺距和不同的对比剂注射方式行上肢动脉CT成像。利用MIP和VR方式重建三维图像;比较不同参数和不同对比剂应用方式的CT上肢动脉图像质量。结果48例病人经足背静脉注射造影剂行双侧上肢动脉成像,其中40个上肢发现有动脉病变,且CT显示病变与手术所见基本相符。经统计学分析,层厚0.6mm螺距1.5组的VR图像评分与层厚0.6mm螺距0.9组无明显差异(t=1.21,P>0.05),而明显高于其他所有组(层厚1.0mm螺距0.9组、层厚1.0mm螺距1.5组、层厚2.0mm螺距0.9组、层厚2.0mm螺距1.5组)的评分(t=3.26,2.25,4.13,2.89,P<0.05)。高压注射器以6.0ml/s双筒依次团注70ml对比剂和50ml生理盐水与单筒以同样速率团注100ml对比剂成像质量评分无明显差异(t=1.30,P>0.05)。结论最佳的参数设置为:螺距1.5,准直64×0.6,层厚0.6mm,重建间隔50%;最佳的对比剂的应用方式为:先70ml对比剂(370mgI/ml浓度)后50ml生理盐水用双筒高压注射器分别以6.0ml/s的注射速度团注入足背静脉,追踪触发扫描方式待主动脉弓CT值达100Hu时再延迟7s开始扫描双侧上肢。

Technical study of CT arteriography for upper extrimity by 64-slice CT

Objective To study the method and the clinical value of the 64-slice CT arteriography (CTA) for upper limb; To find out the best way of injecting contrast medium including injecting mode, velocity, quantity, and the best scan and post-processing parameters. Methods Forty-eight patients in doubt of upper limb artery diseases were scanned by 64-slice CT using different collimation and pitch and by different contrast medium injecting mode. MIP and VR Methods were used to get three-dimension images. Images of upper extremity artery obtained with different parameters and different contrast medium administrating mode were compared within each other. Results Forty-eight patients were successfully performed bilateral upper limb CTA by injecting contrast medium via dorsal vein of foot, among which 40 upper limb were found arterial lesions, and the lesions showed in CTA were roughly the same with what were seem in surgery operation. Statically the image score of the group with slice thickness 0.6 mm and pitch 1.5 had no remarkable difference with that of the group with slice thickness 0.6 mm and pitch 0.9 (t=1.21, P>0.05), but was higher than that of any other groups such as thickness 1.0 mm and pitch 0.9, thickness 1.0 mm and pitch 1.5, thickness 2.0 mm and pitch 0.9, thickness 2.0 mm and pitch 1.5 (t=3.26, 2.25, 4.13, 2.89, P<0.05). The image score of injecting 70 ml contrast medium followed by 50 ml 0.9% Nacl solution at a rate of 6 ml per second had no significant difference with that of only injecting 100 ml contrast medium at the same rate (t=1.30,P>0.05). Conclusion The best scanning and reconstruction parameters are collimation 64 mm×0.6 mm,pitch 1.5, slice thickness 0.6, reconstruction increment 50%. The best mode of contrast medium administration is injecting 70 ml contrast medium (370 mgI/ml) followed by 50 ml 0.9% Nacl solution at a rate of 6 ml per second via dorsal foot vein,and begin to scan the bilateral upper limb at the 7^th second after the CT value of aortic arch gets to 100 Hu using bolus tracking mode monitoring.