血流敏感散相——稳态自由激发序列对小腿动脉成像准确性的研究

Study on the accuracy of blood flow sensitive stationary phase and stationary free sequence in the infragenual arteries

目的探讨血流敏感散相—稳态自由激发序列(FSD-SSFP)对小腿动脉狭窄评估的准确性。方法选择2014年7月—2015年7月首都医科大学附属北京安贞医院收治的16例患有下肢动脉疾病的患者,均进行下肢动脉核磁血管造影(MRA)检查,包括FSD-SSFP、增强MRA(CE-MRA)。所有患者在MRA检查前均进行超声检查,MRA检查结束1周内进行数字减影血管造影(DSA)检查。由2名具有5年心血管图像诊断经验的医生对血管狭窄程度进行评价。用Kappa检验分析MRA观察者间的一致性。用受试者工作特性(ROC)曲线比较FSD-SSFPMRA、CE-MRA、CE-MRA联合FSD-SSFP MRA(CE+FSD MRA)以及超声等4种检查方法诊断血管狭窄病变的准确度。结果以DSA为参照,以DSA为参照,FSD-SSFP MRA和CE-MRA均存在过度评价狭窄程度,超声低估狭窄程度。用DSA做参照标准,ROC曲线分析显示CE+FSD MRA曲线下面积最大(0.929),超声曲线下面积最小(0.860)。狭窄划界值为2时能够获得最大敏感度和特异度。结论在患有下肢动脉疾病患者小腿动脉的无创检查中,FSD-SSFP MRA能够提供高质量的诊断图像,无需对比剂,是CE-MRA良好的补充手段。CE+FSD MRA能够提高血管狭窄诊断的准确度。

Objective To evaluate the diagnostic accuracy of flow-sensitive dephasing-prepared steady-state free precession for imaging infragenual arteries relative to Ultrasound, CE-MRA and DSA.Methods A series of 16 consecutive patients with peripheral arterial disease （PAD） underwent a combined peripheral MRA protocol consisting of FSD-MRA for the calves and large field-of-view CE-MRA.All patients accept ultrasound before MRA.DSA was performed on all patients within 1 week of the MR angiographies.Image quality and degree of stenosis was assessed by two readers with more than 5 years of vascular imaging experience.Inter-observer agreement was determined using kappa statistics.Receiver operating characteristic （ROC） curve analysis determined the diagnostic value of FSD-MRA, CE-MRA, CE-MRA combined with FSD-MRA （CE＋FSD MRA） and ultrasound in predicting vascular stenosis.Results Inter-reader agreement was excellent for both FSD-MRA and CE-MRA.Both of FSD-MRA and CE-MRA carry a stenosis overestimation risk relative to DSA standard.Stenosis was underestimated in ultrasound.With DSA as the reference standard, ROC curve analysis showed that the area under the curve was largest for CE＋FSD MRA（ROC=0.929）and smallest for ultrasound（ROC=0.860）.The greatest sensitivity and specificity were obtained when a cut-off stenosis score of 2 was used.Conclusion In patients with severe PAD, FSD-MRA provides good-quality diagnostic images without a contrast agent and is a good supplement for CE-MRA.CE＋FSD MRA can improve the accuracy of vascular stenosis diagnosis.