三维动态增强MR血管造影在糖尿病足下肢动脉病变中的应用研究

目的：探讨三维动态增强磁共振血管成像（3D CE-MRA）在糖尿病足（DF）下肢动脉病变的应用价值。材料与方法对15例怀疑有下肢血管病变的DF患者行3D FLASH CE-MRA检查，扫描范围自腹主动脉下段至足背动脉，通过后处理技术获得满意的下肢三维血管树像；1周内同时均行数字减影血管造影（DSA）检查。每段血管的狭窄程度被分为：A级（正常/狭窄程度〈50%）、B级（狭窄程度≥50%）、C级（闭塞）3个级别。以DSA为“金标准”，综合评估CE-MRA的准确性。结果（1）15例3D CE-MRA检查，显示满意的血管率达100%。（2）CE-MRA与DSA对DF下肢动脉病变检出一致性较好（一致性检验，Kappa值=0.944〉0.75， P〈0.05）；两种检查技术对血管狭窄程度A与C级判断一致性较好（Kappa值分别为0.94、0.84，均〉0.75，P均〈0.05）；两种检查技术对B级评估一致性一般（Kappa值为0.608，〈0.75〉0.4，P〈0.05）。（3）3D CE-MRA对DF下肢动脉病变阳性诊断率96.0%，假阳性、假阴性分别为3.3%、2.0%，敏感性、特异性分别为98.0%、96.7%。（4）3D CE-MRA对血管狭窄程度A、B、C级敏感性分别为96.7%、80%、84.6%；特异性分别为98.0%、92.9%、97.1%。结论对DF下肢动脉病变检出、血管狭窄程度的评估尤其是A、C级判断，3D CE-MRA与DSA有很好的一致性，虽无法避免假阳性和假阴性，但CE-MRA敏感性、特异性很高且有无创伤性、无辐射、无肾毒性、快速、对比剂较少等优势，有望取代DSA和CTA，作为DF下肢动脉病变的常规检查方法。

Application of three-dimensional dynamic contrast-enhanced magnetic resonance angiography in diagnosing lower extremity arterial disease in patients with diabetic foot

Objective： To investigate the diagnostic value of three- dimensional dynamic contrast enhanced magnetic resonance angiography （3D CE-MRA） in lower extremity arterial disease （LEAD） of diabetic foot （DF）. Materials and Methods：Fifteen diabetic cases suspected of LEAD underwent CE-MRA using 3D FLASH automatic subtraction sequence. Satisfactory lower extremity vasculars were obtained by post progressing techniques. All cases also underwent digital subtraction angiography （DSA） within one week. Stenosis grading of each segment of vascular is divided into three levels：grade A （normal/degree of stenosis〈50%）, grade B （narrowed≥50%）, C （block）. The comprehensive diagnostic value of CE-MRA were analyzed taking DSA as the standard. Results：（1） In 15 cases, all target arteries were well demonstrated and the diagnosis was deifnite. （2） LEAD examined with CE-MRA were well consistent with that of DSA in DF cases （consistency check, Kappa value 0.944〉0.75, P〈0.05）. Two medical imaging examination techniques have well consistency in diagnosing grade A and C of vascular stenosis （Kappa value 0.94, 0.84 respectively, both〉0.75, both P〈0.05）. Two techniques have general consistency in diagnosing grade B of vascular stenosis （Kappa value 0.608, 〈0.75〉0.4, P〈0.05）. （3） The positive of CE-MRA for lower extremity arterial stenosis was 96.0%, the false positive and false negative was 3.3%, 2.0%respectively;the sensitivity and speciifcity was 98.0%, 96.7%respectively. （4）The sensitivity of CE-MRA in diagnosing grade A, B, C of lower extremity artery stenosis of was 96.7%, 80%, 84.6%respectively, the speciifcity 98.0%, 92.9%, 97.1%respectively. Conclusions：3D CE-MRA have well agreement with DSA in the positive and classiifcation of stenosis degree for lower extremity arterial stenosis, especially grade A, C. It is unable to avoid false positives and false negatives, but CE-MRA might be performed as a routine examination method in diagnosing LEAD of DF patients, with high sensitivity, high speciifcity, noninvasive, no radiation, no renal toxicity and quick scaning.