MR纵向弛豫时间定量成像评价肥厚型心肌病心肌纤维化的初步研究

A preliminary study of MR T, mapping for detection of left ventricular myocardial fibrosis inhypertrophic cardiomyopathy

目的探讨纵向弛豫时间定量（T1 mapping）成像对肥厚型心肌病（HCM）纤维化的诊断价值。方法按诊断标准人选48例HCM患者和18名健康志愿者，分别行常规延迟强化（LGE）检查与T1 mapping成像，按HCMLGE有无及程度，分为LGE远处正常区、LGE边缘区、LGE区（分为晕状LGE与典型斑片状LGE），分别测量2组心肌对比剂增强后T．值的变化率并进行卡方检验、两两对比及ROC曲线分析。结果健康志愿者T1值变化率与HCM远离LGE区差异无统计学意义（3．98±3．19和3．36±2．77．t=0．98，P〉0．05），与LGE周边区（13．51±5．67）、晕状区（17．70±5．57）、斑片区（36．62±8．03）比较差异有统计学意义（t值分别为15．28、17．13和47．48，P值均〈0．01）；远处正常区（3．36±2．77）与LGE周边区、晕状区及斑片区比较差异均有统计学意义（t值分别为19．64、20．76和56．64，P值均〈0．01）；LGE周边区与LGE晕状区和斑片区比较差异均有统计学意义（t值分别为6．12和39．90，P值均〈0．01）；LGE晕状区与斑片区比较差异有统计学意义（t=25．63，P〈0．01）。ROC曲线提示T1 mapping成像较传统LGE成像有更大的曲线下面积（0．974±0．050和0．751±0．180）。结论HCM纤维化常见，且受累心肌的纤维化程度不一，T1mapping成像能对HCM患者心肌纤维化的严重程度进行评价，能够发现处于纤维化早期的病变。

Objective To investigate the diagnostic values of T1 mapping imaging for evaluating myocardial fibrosis in patients with hypertrophic cardiomyopathy （HCM）. Methods Forty-eight subjectswith HCM and 18 healthy volunteers underwent conventional late gadolinium enhancement （LGE） MR imaging and T1 mapping imaging. According to the characteristics of LGE, the myocardium in HCM wasdivided into remote area of LGE, peri-LGE, LGE （halo-like LGE and typical patchy LGE）. The changing rates of contrast-enhanced T1 value of these regions were measured and compared with normal volunteers＇myocardium. The Chi-square test, pairwise comparison and ROC used for statistical analysis. Results The changing rate of T1 value （CRT） in healthy volunteers was no significant differencefrom that in the remote area of LGE （3.98 ±3.19 vs. 3.36 ±2.77,t =0.98,P 〉0.05）.There were significant differences in CRT between healthy volunteers＇ myocardium and the peri-LGE （ 13.51 ± 5.67 ） ,halo-like LGE （ 17.70 ± 5.57 ） and typical patchy LGE （ 36. 62 ± 8.03, t = 15.28, 17. 13 and 47.48, respectively ,all P 〈 0. 01 ） ,between remote area-LGE and peri-LGE, halo-like LGE and typical patchy LGE（t = 19. 64,20. 76 and 56. 64,respectively,all P 〈 0. 01 ）, between peri-LGE and halo-like LGE and typical patchy LGE （t = 6. 12 and 39. 90, respectively, both P 〈 0. 01 ）, between halo-like LGE and typical patchyLGE（t = 25.63, P 〈 0. 01 ）. ROC curves indicated that T1 mapping imaging has a greater area under the curve than that of traditional LGE imaging （0. 974 ± 0. 050 vs. 0. 751 ± 0. 180）. Conclusion T1 mapping imaging can be a useful method to evaluate the severity of the fibrosis, especially at the early stage.