Li Minghua, Zhang Jiayin, Zhang Qingyong, Pan Jingwei, Lu Zhigang, Wei Meng
Department of Radiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No.600, Yishan Rd, 200233, Shanghai, China.
Eur Radiol. 2015 Feb;25(2):568-74. doi: 10.1007/s00330-014-3429-x. Epub 2014 Sep 26.
To evaluate the incidence and diagnostic performance of reverse attenuation gradient (RAG) sign in patients with coronary stent occlusion.
We retrospectively included patients with suspected restenosis who underwent both coronary computed tomography angiography (CCTA) and invasive coronary angiography (ICA) within 2 weeks. Stent occlusion at CCTA was defined as (1) complete contrast filling defect of large calibre stents (at least 3 mm), or (2) presence of RAG sign in patients with small calibre stents (less than 3 mm) or (3) presence of RAG sign in patients with non-diagnostic image quality of stents. The diagnostic performance of RAG sign was further assessed by comparison to ICA results.
A total of 162 patients with 231 implanted stents were included. ICA confirmed stent occlusion in 59 patients (99 stents). RAG sign was present in 59.3% (35/59) of all stent occlusions. As shown by patient-based analysis, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of our diagnostic criteria for detection of stent occlusion were 79.7% (47/59), 100% (103/103), 100% (47/47) and 89.6% (103/115) respectively. Superior diagnostic performance was confirmed by receiver operating characteristic (ROC) analysis with an area under the curve of 0.898.
RAG sign observed at CCTA in patients with coronary stenting represents reverse collateral flow distal to stents and is highly specific to indicate stent occlusion.
• RAG sign in patients with previous stents represents retrograde collateral flow. • RAG sign in patients with previous stents indicates stent occlusion. • RAG sign improves detection of stent occlusion in small calibre stents.
评估冠状动脉支架闭塞患者中反向衰减梯度（RAG）征的发生率及诊断效能。
我们回顾性纳入了在2周内同时接受冠状动脉计算机断层扫描血管造影（CCTA）和有创冠状动脉造影（ICA）的疑似再狭窄患者。CCTA上的支架闭塞定义为：（1）大口径支架（至少3 mm）完全造影剂充盈缺损，或（2）小口径支架（小于3 mm）患者出现RAG征，或（3）支架图像质量无法诊断的患者出现RAG征。通过与ICA结果比较，进一步评估RAG征的诊断效能。
共纳入162例植入231个支架的患者。ICA证实59例患者（99个支架）存在支架闭塞。所有支架闭塞中59.3%（35/59）出现RAG征。基于患者的分析显示，我们检测支架闭塞的诊断标准的敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV）分别为79.7%（47/59）、100%（103/103）、100%（47/47）和89.6%（103/115）。受试者操作特征（ROC）分析证实了其卓越的诊断效能，曲线下面积为0.898。
冠状动脉支架置入患者CCTA上观察到的RAG征代表支架远端的反向侧支血流，对提示支架闭塞具有高度特异性。
•既往有支架患者的RAG征代表逆行侧支血流。•既往有支架患者的RAG征提示支架闭塞。•RAG征提高了小口径支架闭塞的检测率。
