心脏MR非对比增强纵向弛豫时间定量成像在左心室肥厚中的鉴别诊断价值

Assessment of left ventricular hypertrophy using non-contrast T, mapping

目的 评价心脏MR非对比增强纵向弛豫时间定量成像（T1mapping技术）在左心室肥厚（LVH）中的诊断价值.方法 回顾性搜集2015年11月至2016年10月临床诊治的LVH患者40例（LVH组）,包括11例心肌淀粉样变性（CA）、19例肥厚型心肌病（HCM）及10例高血压性心脏病（HHD）,另有14名健康志愿者为正常对照组,所有受试者均在3.0TMR扫描仪上行心脏MR检查.扫描序列包括电影序列、首过灌注、延迟增强及非对比增强T1mapping.观察电影序列、心肌灌注及延迟增强的心脏形态学表现,并按照美国心脏学会（AHA）分段法分析左心室心肌16个心肌节段（心尖部除外）,测量每个肥厚心肌节段舒张末期左心室壁厚度及肥厚心肌节段的心肌初始T1值.以独立样本t检验分析LVH组与正常对照组间数据的差异;以单因素方差分析（ANOVA）及LSD两两比较法分析LVH 3个亚组与正常对照组间T1值及舒张末左心室壁厚度的差异;并用ROC曲线分析心肌T1值在3个LVH亚组间的诊断效能.结果 LVH组的舒张末期左心室壁厚度[（16.5±5.2）mm]及初始T1值[（1388.6±119.8）ms]均大于正常对照组[（6.3±1.8）mm、（1248.4±58.1）ms）],差异具有统计学意义（t值分别为28.8、16.4, P值均〈0.01）,其中CA患者心肌初始T1值[（1495.5±100.9）ms]明显高于HCM [（1342.0±69.2）ms]及HHD患者[（1290.7±45.5）ms],差异具有统计学意义（F=300.5,P〈0.01）,HCM初始T1值高于HHD（P〈0.01）;HCM的左心室壁厚度大于CA及HHD患者（P〈0.01）,CA患者的左心室壁厚度大于HHD患者（P〈0.01）.心肌初始T1值诊断CA及HCM的敏感度、特异度、截断值及曲线下面积分别为90.1%、84.3%、1382.8 ms及0.914;诊断CA与HHD的敏感度、特异度、截断值及曲线下面积分别为97.0%、93.5%、1359.5 ms及0.989.结论 心脏MR非对比增强T1mapping值的增高程度可定量评估LVH心肌组织学特征,并帮助临床对其进行鉴别诊断.

Objective To study the diagnostic value of non-contrast T1mapping in left ventricular hypertrophy（LVH）.Methods Forty LVH patients（LVH group）including 11 cardiac amyloidosis（CA）,19 hypertrophic cardiomyopathy （HCM） and 10 hypertensive heart disease （HHD） patients, and 14 healthy volunteers （control group） were enrolled in this retrospective study between November 2015 and October 2016.All subjects underwent cardiac magnetic resonance（CMR）on a 3 T scanner.The CMR scan protocol included cine sequences, first-pass perfusion, late Gadolinium enhancement （LGE） and non-contrast T1 mapping（MOLLI）prototype sequences.The cardiac morphology was assessed by cine,first-pass perfusion as well as LGE.Left-ventricular end-diastolic wall thickness（EDTH）was assessed for 16 segments,native T1 values were measured in hypertrophic segments. The differences in EDTH and native T1values between LVH group and control group were evaluated using t test. The ANOVA and LSD were used in the comparison of differences among four sub-groups.Sensitivity,specificity,cut-off values and area under the curve （AUC） were derived using receiver-operating characteristics curve （ROC） analysis. Results The EDTH and native T1values in LVH group were significantly higher than those of control group[（16.5±5.2）mm vs.（6.3±1.8）mm,（1 388.6±119.8）ms vs.（1 248.4±58.1）ms,t=28.8 16.4,both P〈0.01].Moreover,CA showed significantly higher T1value [（1 495.5 ± 100.9）ms] than that of HCM [（1 342.0 ± 69.2）ms] and HDD [（1 290.7±45.5）ms]（F=300.5,P〈0.01）,and T1values in HCM were also higher than HDD（P〈0.01）.HCM showed significantly higher EDTH than that of CA and HDD （P〈0.01）, and EDTH in CA was also higher than HDD （P〈0.01）. The native T1showed good diagnostic performance between CA and HCM with AUC 0.914,sensitivity 90.1%%,and specificity 84.3%,and cutoff value 1 382.8 ms,between CA and HHD with AUC 0.989,sensitivity 97.0%,specificity 93.5% and cutoff value 1 359.5 ms.Conclusion The elevated native T1values were useful for quantitatively differential diagnosis of LVH.