心脏磁共振T1 mapping技术评估肥厚型心肌病心肌纤维化

Evaluation of Myocardial Fibrosis in Hypertrophic Cardiomyopathy via Cardiac Magnetic Resonance T1 Mapping

目的 基于心脏磁共振(CMR)T1 mapping技术定量评估肥厚型心肌病(HCM)心肌纤维化。资料与方法 回顾性收集2019年6月—2021年7月昆明医科大学第一附属医院45例HCM患者(HCM组)及44例CMR结果正常者(对照组)的临床及CMR资料,所有患者均行CMR检查,包括T1 mapping序列、延迟强化(LGE)扫描,图像于后处理工作站分析处理,得出心功能参数,测量各段及整体心肌的增强前T1值、增强后T1值及心肌细胞外容积分数(ECV)。结果 HCM组左心室整体、肥厚段及非肥厚段心肌的增强前T1值和ECV均高于对照组(t=2.83、2.63,P均<0.05);HCM组中肥厚段心肌的增强前T1值和ECV均高于非肥厚段(t=2.74、2.54,P均<0.05);HCM组中26例LGE阳性患者左心室整体增强前T1值和ECV均高于HCM组中19例LGE阴性患者(t=2.57、2.70,P均<0.05);LGE阳性患者肥厚段及非肥厚段心肌的增强前T1值和ECV均高于对照组(t=3.14、2.27,P均<0.05);LGE阳性患者肥厚段心肌ECV高于非肥厚段(t=2.95,P=0.024)。LGE阴性患者仅肥厚段心肌的增强前T1值和ECV均高于对照组(t=3.08、2.51,P均<0.05);LGE阴性患者肥厚段心肌ECV高于非肥厚段(t=2.65,P=0.028)。增强前T1值和ECV鉴别HCM与对照组的受试者工作特征曲线下面积分别为0.767、0.800,联合心肌质量后的曲线下面积分别为0.877、0.879,其中ECV联合心肌质量鉴别HCM与对照组的敏感度为73.52%,特异度为95.45%。结论 基于CMR的T1 mapping技术可以定量评估肥厚型心肌病患者心肌纤维化。肥厚型心肌病患者心肌增强前T1和ECV升高,提示心肌纤维化,且肥厚段较非肥厚段心肌纤维化明显。此外,T1 mapping可早于LGE发现肥厚型心肌病患者心肌纤维化,以ECV诊断效能较高,ECV联合心肌质量可以进一步提高肥厚型心肌病的诊断率。

Purpose To quantitatively analyze the myocardial fibrosis in hypertrophic cardiomyopathy(HCM) via cardiac magnetic resonance(CMR) T1 mapping. Materials and Methods Forty-five patients with HCM and 44 age-and gender-matched controls(control group) who underwent CMR from June 2019 to July 2021 were retrospectively enrolled. The clinical and CMR imaging data, including T1mapping sequence and late gadolinium enhancement(LGE) sequence, were also obtained. After processing on the post-processing workstation,the cardiac function parameters were obtained and the myocardial native T1 value, enhanced T1 value, and extracellular volume fraction(ECV)were further measured. Results The native T1 and ECV of whole left ventricle, hypertrophic segment, and non-hypertrophic segment myocardium of HCM patients were significantly higher than those of controls(t=2.83 and 2.63, P<0.05). In HCM group, the native T1 and ECV of hypertrophic segment were significantly higher than those of non-hypertrophic segment(t=2.74 and 2.54, P<0.05). In HCM group,native T1 and ECV of LGE positive patients were significantly higher than those of LGE negative patients(t=2.57 and 2.70, P<0.05). Native T1 and ECV of myocardial hypertrophy and non-hypertrophy of LGE positive HCM patients were significantly higher than those of controls(t=3.14 and 2.27, P<0.05). In positive HCM patients, the ECV of myocardial hypertrophy was significantly higher than those of myocardial non-hypertrophy(t=2.95, P=0.024). In LGE negative patients, the native T1 value and ECV of hypertrophic myocardia were significantly higher than those of controls(t=3.08 and 2.51, P<0.05). In LGE negative patients, the ECV of hypertrophic myocardia were significantly higher than those of non-hypertrophic myocardia(t=2.65, P=0.028). The area under the curve of native T1 and ECV of differentiating HCM patients from the controls was 0.767 and 0.800, and the area under the curve combined with myocardial mass was 0.877 and 0.879, respectively.The sensitivity and specificity of ECV combined with myocardial mass in differentiating HCM patients from the controls were 73.52% and 95.45%, respectively. Conclusion Myocardial fibrosis in patients with HCM can be quantitatively assessed based on CMR T1 mapping.Myocardial native T1 and ECV are elevated in HCM patients, suggesting myocardial fibrosis. In addition, T1 mapping can detect myocardial fibrosis in patients with HCM earlier than LGE.