Quantitative myocardial perfusion mapping using cardiovascular magnetic resonance (CMR) is validated for myocardial blood flow (MBF) estimation in native vessel coronary artery disease (CAD). Following coronary artery bypass graft (CABG) surgery, perfusion defects are often detected in territories supplied by the left internal mammary artery (LIMA) graft, but their interpretation and subsequent clinical management is variable. We assessed myocardial perfusion using quantitative CMR perfusion mapping in 38 patients with prior CABG surgery, all with angiographically-proven patent LIMA grafts to the left anterior descending coronary artery (LAD) and no prior infarction in the LAD territory. Factors potentially determining MBF in the LIMA–LAD myocardial territory, including the impact of delayed contrast arrival through the LIMA graft were evaluated. Perfusion defects were reported on blinded visual analysis in the LIMA–LAD territory in 27 (71%) cases, despite LIMA graft patency and no LAD infarction. Native LAD chronic total occlusion (CTO) was a strong independent predictor of stress MBF (B = − 0.41, p = 0.014) and myocardial perfusion reserve (MPR) (B = − 0.56, p = 0.005), and was associated with reduced stress MBF in the basal (1.47 vs 2.07 ml/g/min; p = 0.002) but not the apical myocardial segments (1.52 vs 1.87 ml/g/min; p = 0.057). Extending the maximum arterial time delay incorporated in the quantitative perfusion algorithm, resulted only in a small increase (3.4%) of estimated stress MBF. Perfusion defects are frequently detected in LIMA–LAD subtended territories post CABG despite LIMA patency. Although delayed contrast arrival through LIMA grafts causes a small underestimation of MBF, perfusion defects are likely to reflect true reductions in myocardial blood flow, largely due to proximal native LAD disease.

中文翻译：

---

使用定量心血管磁共振心肌灌注图来表征左内乳冠状动脉搭桥术患者的缺血特征

使用心血管磁共振 (CMR) 进行的定量心肌灌注图对于自体血管冠状动脉疾病 (CAD) 的心肌血流量 (MBF) 估计已得到验证。冠状动脉旁路移植术（CABG）手术后，经常在左乳内动脉（LIMA）移植物供应的区域检测到灌注缺陷，但其解释和随后的临床治疗是可变的。我们使用定量 CMR 灌注图对 38 名接受过 CABG 手术的患者进行了心肌灌注评估，所有患者均在左冠状动脉前降支 (LAD) 上进行了经血管造影证实的专利 LIMA 移植物，并且 LAD 区域既往没有梗塞。评估了可能决定 LIMA-LAD 心肌区域 MBF 的因素，包括通过 LIMA 移植物延迟造影剂到达的影响。尽管 LIMA 移植物通畅并且没有 LAD 梗塞，但在 27 例 (71%) 病例中，盲法视觉分析报告了 LIMA-LAD 区域的灌注缺陷。天然 LAD 慢性完全闭塞 (CTO) 是应激 MBF (B = − 0.41，p = 0.014) 和心肌灌注储备 (MPR) (B = − 0.56，p = 0.005) 的强大独立预测因子，并且与应激减轻相关基底心肌节段的 MBF 为（1.47 vs 2.07 ml/g/min；p = 0.002），但心尖心肌段则不然（1.52 vs 1.87 ml/g/min；p = 0.057）。延长定量灌注算法中的最大动脉时间延迟仅导致估计应力 MBF 略有增加 (3.4%)。尽管 LIMA 通畅，但 CABG 后 LIMA-LAD 覆盖区域经常检测到灌注缺陷。尽管通过 LIMA 移植物延迟造影剂到达会导致 MBF 被小幅低估，但灌注缺陷可能反映了心肌血流量的真正减少，这主要是由于近端天然 LAD 疾病所致。