Influence of observer-dependency on left ventricular hypertrabeculation mass measurement and its relationship with left ventricular volume and ejection fraction – comparison between manual and semiautomatic CMR image analysis methods

BackgroundRecent studies concerning left ventricular noncompaction (LVNC) suggest that the extent of left ventricular (LV) hypertrabeculation has no impact on prognosis. The variety of methods of LV noncompacted myocardial mass (NCM) assessment may influence the results. Hence, we compared two methods of NCM estimation: largely observer-independent Hautvast’s(H) computed algorithm-based approach and commonly used Jacquier’s(J) method, and their associations with LV end-diastolic volume (EDV) and ejection fraction (EF).MethodsCardiac magnetic resonance images of 77 persons (45±17yo) - 42 LVNC, 15 non-ischemic dilative cardiomyopathy, 20 control group were analyzed. LVNC patients were divided into the subgroup with normal (LVNCN) and high EDV (LVNCDCM). NCM and total left ventricular mass (LVM) were estimated by Hautvast’s [excluding intertrabecular blood (ITB) and including papillary muscles (PMs) into NCM] and Jacquier’s approach (including ITB and PMs, if unclearly distinguished, into NCM).ResultsThe cut-off value of NCM for LVNC diagnosis was 22% (AUC 0.933) for NCMH/LVMH and 26% (AUC 0.883) for NCMJ/LVMJ. Inter- and intra-observer variability (estimated by coefficient of variation [CoV] and intraclass correlation coefficient [ICC]) of NCMH/LVMH appeared better than of NCMJ/LVMJ (CoV 4.3%, ICC 0.981 and CoV 4.9%, ICC 0.978; respectively for NCMH/LVMH, while for NCMJ/LVMJ: CoV 19.7%, ICC 0.15 and CoV 12.9%, ICC 0.504). In LVNCN subgroup, the correlation between EDV and NCMH was stronger than NCMJ (r = 0.677, pH/LVMH (r = 0.391, pJ/LVMJ. In the overall group a relationship was present between EF and NCMH/LVMH (r = -0.449, pJ/LVMJ. Only NCMH/LVMH explained the variability of EDV (b 0.434, pConclusionsChoosing a method of NCM assessment that is less observer-dependent might increase the reliability of results. The impact of method selection on the LV parameters and cut-off values for hypertrabeculation should be further investigated.背景 近期针对左心室非致密化心肌病（left ventricular noncompaction, LVNC）的研究表明，左心室（left ventricular, LV）肌小梁增多的程度对患者预后无影响。左心室非致密心肌质量（noncompacted myocardial mass, NCM）的评估方法多样，可能会对研究结果产生影响。因此，本研究对比了两种NCM估算方法：基本不依赖观察者的基于计算算法的豪瓦斯特（Hautvast, H）法，以及临床常用的雅克里耶（Jacquier, J）法，并分析了两种方法所得结果与左心室舒张末期容积（left ventricular end-diastolic volume, EDV）和射血分数（ejection fraction, EF）的相关性。 方法 本研究分析了77名受试者（年龄45±17岁）的心脏磁共振图像，其中包括42名LVNC患者、15名非缺血性扩张型心肌病患者以及20名健康对照者。将LVNC患者分为左心室舒张末期容积正常亚组（LVNCN）和左心室舒张末期容积升高亚组（LVNCDCM）。分别采用Hautvast法和Jacquier法估算NCM及左心室总质量（left ventricular mass, LVM）：Hautvast法需排除小梁间隙血液（intertrabecular blood, ITB），并将乳头肌（papillary muscles, PMs）纳入NCM计算；Jacquier法则将小梁间隙血液及分界不清的乳头肌均纳入NCM计算。 结果 以基于Hautvast法的NCM与LVM比值（NCMH/LVMH）为诊断指标时，LVNC的截断值为22%（受试者工作特征曲线下面积AUC=0.933）；以基于Jacquier法的NCM与LVM比值（NCMJ/LVMJ）为指标时，截断值为26%（AUC=0.883）。采用变异系数（coefficient of variation, CoV）和组内相关系数（intraclass correlation coefficient, ICC）评估的NCMH/LVMH的观察者间及观察者内变异程度均优于NCMJ/LVMJ：NCMH/LVMH的观察者间变异系数为4.3%、组内相关系数为0.981，观察者内变异系数为4.9%、组内相关系数为0.978；而NCMJ/LVMJ的观察者间变异系数为19.7%、组内相关系数为0.15，观察者内变异系数为12.9%、组内相关系数为0.504。在LVNCN亚组中，EDV与NCMH的相关性强于与NCMJ的相关性（r = 0.677, pH/LVMH (r = 0.391, pJ/LVMJ）。在全部受试者中，EF与NCMH/LVMH存在相关性（r = -0.449, pJ/LVMJ）。仅NCMH/LVMH可解释EDV的变异（b = 0.434, p）。 结论 选择依赖观察者程度更低的NCM评估方法，可提升研究结果的可靠性。评估方法的选择对左心室相关参数及肌小梁增多截断值的影响，仍需进一步开展研究。