Tim技术3D DCE-MRA诊断下肢动脉狭窄:与DSA对比研究

Comparative Study of DSA and 3D Enhanced MR Angiography with Tim Techniques in Lower Extremity Artery Stenosis

目的以数字减影血管造影（DSA）为金标准,对比评价Tim（total image matrix）技术三维动态增强磁共振血管成像（3DDCE-MRA）在下肢动脉（腘股段和腘下段）狭窄中的临床应用价值。资料与方法41例可疑下肢动脉狭窄患者,采用Tim线圈、多通道并行采集技术,并结合自动移床及无缝连接方法,行3DDCE-MRA检查。延迟时间采用试验团注（test-bolus）法,对靶血管作最大信号强度投影（MIP）后处理重组。所有病例均在1周内行动脉法DSA（IADSA）检查,对比分析3DDCE-MRA所示的轻度狭窄（≤50%）、显著狭窄（51%-99%）、完全闭塞（100%）的符合情况,并计算显示显著狭窄及完全闭塞的敏感性和特异性。结果图像质量的优良率为95.1%。与IADSA对照,3DDCE-MRA显示腘股动脉段显著狭窄及完全闭塞（狭窄程度〉50%）的敏感性91.1%,特异性92.9%,准确性92.3%;显示腘下动脉段的敏感性82.2%,特异性75.4%,准确性83.9%;显示下肢动脉狭窄总的准确性为87.5%。结论Tim线圈、多通道并行采集技术3DDCE-MRA是一种诊断下肢动脉狭窄的无创、安全、可靠、实用的血管检查方法,对腘股动脉段狭窄的诊断更加可靠,但对细小血管（尤其足部）的分辨率尚有待于进一步提高。

Objective To evaluate the clinical application of 3D dynamic contrast enhanced MR angiography （3D DCEMRA） with the techniques of total image matrix （Tim） in diagnosing lower extremity （femoropopliteal and infrapopliteal） artery stenosis, and compared with DSA as the golden standard, Materials and Methods 3D DCE MRA was performed in 41 cases suspected of lower extremity stenosis with the techniques of Tim coil, multireceiving channels and integrated parallel acquisition techniques （iPAT）, automatic bed moving and nongap composing. The delay time was determined by Test bolus. 3D MIP reconstruction was used in the post processing. All cases were proved by IADSA in one week after 3D DCE MRA examination. Moderate stenosis （luminal narrowing≤ 50% ）, significant stenosis （luminal narrowing 51% - 99% ） and occlusion（luminal narrowing of 100% ） were identified on 3D DCE MRA. The sensitivity and specificity of significant stenosis and occlusion were calctdated. Results Good image quality was 95. 1 % . Compared with IADSA, the sensitivity, specificity and accuracy of 3D DCE MRA in diagnosing significant stenosis and occlusion （≥50% stenosis） of femoropopliteal arteries were 91.1% , 92.9% and 92.3%, respectively. The sensitivity, specificity and accuracy in diagnosing significant stenosis and occlusion （≥ 50% stenosis） of ird＇rapopliteal arteries were 82.2%, 75.4% and 83.9%, respectively. Conclusion 3D DCE MRA with the techniques of Tim coil, mtdtireceiving channels and iPAT techniques is a noninvasive, safe, accurate and practical method of diagnosing lower extremity artery diseases, which is more reliable in diagnosing stenosis of femoropopliteal arteries, but its resolution rate of smaller vessels （ such as foot arteries） should be further improved.