Jiemin Z, Zhuhua Z, Yuqing L
Department of Radiology, Peking Union Medical College Hospital, CAMS & PUMC, Beijing 100730.
Chin Med Sci J. 2000 Jun;15(2):67-72.
To make a preliminary investigation of the patency and function of coronary artery bypass grafts (CABG) by magnetic resonance (MR) images and to establish a suitable method for follow-up study after CABG operation among Chinese.
MR imaging was performed with a Toshiba 1.5-T unit in 27 patients with 74 grafts. All patients were examined with a breath-hold ECG-gated two-dimensional fast field echo (FFE) sequence to evaluate the patency of bypass grafts, among them 16 patients with 42 grafts were further examined with a phase shift magnetic resonance angiography flow (PSMRAflow) sequence to evaluate the grafts patency as well as the flow velocity and flow volume vs. time.
The results showed that 66 of the 74 grafts in the patients of the present series studied with FFE were patent with a patency rate of 89.2%. The results evaluated both with FFE and PSMRAflow remained the same except that two grafts were patent with FFE and the results with PSMRAflow were uncertain. Diastolic perfusion pattern curves were found in 25 of the 32 grafts in patients of the present series. Comparing the flow curves of the grafted left internal mammary artery with those of the native right internal mammary artery in 7 patients, the systolic peak velocity value (SPV) of the grafted arteries was significantly lower than that of the ungrafted ones, whereas the diastolic peak velocity value (DPV) and the ratio of DPV to SPV were significantly greater than that of the ungrafted ones.
The FFE and PSMRAflow sequences were efficient in evaluating patency and obtaining the curves of flow velocity and volume of the bypass grafts. Therefore, they may offer a non-invasive screening method for follow-up study in patients after CABG surgery, although its accuracy should be further evaluated in more patients and comparatively studied with other methods.
通过磁共振（MR）图像对冠状动脉旁路移植术（CABG）的血管通畅性及功能进行初步研究，并建立适合中国人群CABG术后随访研究的方法。
使用东芝1.5-T设备对27例患者的74条移植血管进行MR成像检查。所有患者均采用屏气心电图门控二维快速场回波（FFE）序列评估移植血管的通畅性，其中16例患者的42条移植血管进一步采用相移磁共振血管造影血流（PSMRAflow）序列评估血管通畅性以及流速和流量随时间的变化情况。
本研究系列患者中，采用FFE序列研究的74条移植血管中有66条通畅，通畅率为89.2%。除两条移植血管FFE显示通畅但PSMRAflow结果不确定外，FFE和PSMRAflow评估结果一致。本研究系列患者的32条移植血管中有25条出现舒张期灌注模式曲线。比较7例患者移植的左乳内动脉与自身右乳内动脉的血流曲线，移植动脉的收缩期峰值速度值（SPV）明显低于未移植动脉，而舒张期峰值速度值（DPV）以及DPV与SPV的比值明显高于未移植动脉。
FFE和PSMRAflow序列在评估移植血管通畅性及获取流速和流量曲线方面是有效的。因此，它们可为CABG术后患者的随访研究提供一种非侵入性筛查方法，尽管其准确性仍需在更多患者中进一步评估并与其他方法进行比较研究。
