心肌桥对近段冠状动脉脂肪衰减指数的影响：无斑块人群双中心研究
该双中心回顾性研究纳入 2,094 例无斑块左前降支心肌桥-壁冠状动脉患者与 1,126 例 CCTA 正常对照，测量心肌桥入口近段 2 cm 的冠状动脉周围脂肪衰减指数（FAI）。经 1:1 倾向评分匹配 769 对后，心肌桥组近段 FAI 高于对照，并随心肌桥厚度增加而升高。多因素分析显示心肌桥厚度与近段 FAI 升高独立相关（OR=3.103，95%CI 2.537-3.796，P<0.001）。
要点
- CCTA 报告 LAD 心肌桥时，应测量收缩期心肌桥厚度并分级，厚度信息比长度更相关。
- 心肌桥近段 2 cm 的 FAI 升高可能受心肌桥影响，不宜直接归因于斑块或血管炎症。
- 心肌桥越深，近段 FAI 越高；深桥（≥2 mm）厚度与 FAI 中等正相关（r=0.463）。
核心结论
- 左前降支心肌桥-壁冠状动脉的存在、尤其是深桥，与无斑块人群近段冠状动脉周围脂肪衰减指数升高相关，心肌桥厚度而非长度是主要相关解剖参数。
研究设计与样本
- 双中心回顾性研究，纳入 2,094 例无动脉粥样硬化斑块的左前降支心肌桥-壁冠状动脉患者与 1,126 例 CCTA 正常对照。
- 心肌桥厚度与长度在收缩期 CCTA 图像上评估，FAI 测量范围为心肌桥入口近段 2 cm 节段。
- 经 1:1 倾向评分匹配后，769 对心肌桥与对照纳入比较。
关键影像表现/征象
- CCTA 收缩期图像可显示左前降支心肌桥的厚度与长度。
- 心肌桥近段 FAI 中位 HU 值随厚度增加而升高：对照 -90、浅表 -83、中等深度 -78、极深 -68（P<0.001）。
- 所有心肌桥组近段 FAI 均显著高于对照。
- 深部心肌桥亚组（厚度 ≥2 mm）中，心肌桥厚度与 FAI 呈中等正相关（r=0.463，P<0.001）。
- 心肌桥长度与 FAI 无显著相关（r=0.023，P=0.45）。
诊断标准与关键数值
- 心肌桥厚度分组标准：浅表 <2 mm、中等深度 2-5 mm、极深 ≥5 mm。
- 多因素逻辑回归显示，心肌桥厚度与近段 FAI 升高独立相关（OR=3.103，95%CI 2.537-3.796，P<0.001）。
- 深桥亚组中，心肌桥厚度与 FAI 相关系数 r=0.463（P<0.001），心肌桥长度与 FAI 相关系数 r=0.023（P=0.45）。
- 各组近段 FAI 中位 HU：对照 -90，浅表 -83，中等深度 -78，极深 -68。
临床应用与阅片要点
- CCTA 报告 LAD 心肌桥时，记录收缩期心肌桥厚度分级，并结合近段 FAI 结果综合解读。
- 看到心肌桥近段 FAI 升高时，应考虑心肌桥本身对冠状动脉周围脂肪衰减的影响，避免误判为斑块相关炎症。
- 应在收缩期 CCTA 图像上评估心肌桥厚度与长度，厚度对近段 FAI 更有参考价值。
局限性
- 回顾性研究设计，因果推断受限。
- 仅纳入无动脉粥样硬化斑块人群，结果不宜直接外推至有斑块患者。
- FAI 为影像衍生的替代指标，并非冠状动脉周围炎症的直接测量。
以上解读依据论文摘要（全文未开放获取或许可不允许翻译转载）。
英文原文（摘要）· 点击展开
AIM: The left anterior descending (LAD) myocardial bridge-mural coronary artery (MB-MCA) complex is a common coronary anatomical variation. The pericoronary fat attenuation index (FAI), derived from coronary computed tomography angiography (CCTA), is an imaging biomarker associated with pericoronary adipose tissue attenuation changes and should be interpreted as an imaging-derived surrogate rather than a direct measure of vascular inflammation. This study aimed to investigate the association between MB-MCA, particularly its morphological characteristics, and proximal pericoronary FAI in a plaque-free population.
MATERIALS AND METHODS: In this dual-centre retrospective study, 2,094 patients with LAD MB-MCA without atherosclerotic plaque and 1,126 controls with normal CCTA findings were analysed. According to MB thickness, patients were categorised into superficial (<2 mm), moderate-depth (2-5 mm), and extreme-depth (≥5 mm) groups. FAI was measured in a 2 cm segment proximal to the MB entrance. MB thickness and length were assessed on systolic-phase CCTA images. Between-group comparisons, correlation analyses, and multivariable logistic regression analyses were performed.
RESULTS: After 1:1 propensity score matching (769 pairs), proximal FAI remained significantly higher in the MB group than in matched controls. Proximal FAI values were significantly higher in all MB groups than in controls and increased progressively with greater MB thickness (median Hounsfield unit [HU]: control -90, superficial -83, moderate-depth -78, extreme-depth -68; P < 0.001). Within the deep MB subgroup (MB thickness ≥2 mm), MB thickness showed a moderate positive correlation with FAI (r = 0.463, P < 0.001), whereas MB length was not significantly correlated with FAI (r = 0.023, P = 0.45). On multivariable analysis, MB thickness remained independently associated with elevated FAI (odds ratio [OR] = 3.103, 95% confidence interval [CI]: 2.537-3.796, P < 0.001).
CONCLUSION: The presence of an LAD MB-MCA, particularly deep bridges, is associated with higher proximal pericoronary FAI values in a plaque-free population. MB thickness, rather than length, was the primary anatomical parameter associated with FAI elevation.
引用
- Xu, Fu, Hao, et al. Effect of myocardial bridging on the fat attenuation index of proximal coronary arteries: a dual-centre study in a plaque-free population. Clin Radiol. 2026. PMID: 42320316. doi:10.1016/j.crad.2026.107397
供执业医师工作参考，不替代临床判断；数值与分级以指南原文为准。