mDIXON直方图参数在下肢原发性淋巴水肿分度中应用价值的初探

The Value of mDIXON Histogram Parameters in Grading Primary Lymphedema of Lower Extremity

目的探究mDixon直方图参数对下肢原发性淋巴水肿(PLEL)分度的效能。方法回顾性纳入74例下肢PLEL患者,其中轻度(Ⅰ度)患者21例、中度(Ⅱ度)患者18例、重度(Ⅲ度)患者35例。在患者mDixon图中用ITK-snap软件中半自动阈值法填充患者水肿部位皮下组织与肌肉间区域,再由医师逐层擦除区域外组织并生成感兴趣区(ROI)。应用FAE软件,提取ROI处参数:百分位数(10%,90%)、最大值、最小值、均值、极差、偏度、均方根差、峰度、方差。使用单因素方差分析与非参数检验进行组间差异性分析,两两比较使用LSD法与全部成对法。应用受试者工作特征(ROC)曲线鉴别组间具有统计学意义的参数对轻度组与非轻度组、重度组与非重度组的诊断效能并计算其灵敏度和特异度。结果Ⅰ度、Ⅱ度、Ⅲ度患者直方图参数中:百分位数(10%、90%)、最大值、最小值、均值、极差、偏度、均方根值,三组间差异具有统计学意义。峰度、方差,三组间差异无统计学意义。选取三组间有统计学差异的参数对轻度组与非轻度组进行ROC分析,第10百分位数的曲线下面积(AUC)值为0.74,95%置信区间(CI):0.62~0.87,敏感度为54.7%,特异度为90.5%。最大值、极差特异度最高为100%,第90百分位数、均方根值敏感度最高为73.6%。选取三组间有统计学差异的参数对重度组与非重度组进行ROC分析,第10百分位数的AUC值为0.86,95%CI:0.77~0.95,敏感度为71.4%,特异度为92.3%。最大值、极差特异度最高为94.9%,均值、均方根值、偏度敏感度最高为85.7%。结论mDixon直方图参数对下肢PLEL分度有一定诊断效能。

Objective To investigate the diagnostic efficacy of mDixon histogram parameters in distinguishing grade of primary lymphedema of lower extremity.Methods Seventy-four patients with primary lymphedema of lower extremity,21 cases were mild(Ⅰdegree),18 cases were moderate(Ⅱdegree),35 cases were severe(Ⅲdegree).In the mDixon image of the patient,the subcutaneously and intramuscular area of the edema was filled with the semi-automatic threshold method in ITK-snap software,the doctor erases the tissue out of the region layer by layer and generates the region of interest(VOI).Parameters of VOI were extracted by FAE software:percentile(10%,90%),maximum,minimum,mean,range,skewness,root mean square difference,kurtosis,variance.One-way ANOVA and nonparametric tests were used for analysis of differences between groups,with pairwise comparisons using the LSD method and all paired methods.Receiver operating characteristic(ROC)curves were used to identify and calculate the diagnostic efficacy of statistically significant parameters between groups for mild and non-mild,severe and non-severe sensitivity and specificity.Results In the histogram parameters ofⅠdegree,Ⅱdegree andⅢdegree patients:percentile(10%,90%),maximum,minimum,mean,range,skewness,root mean square difference,the differences among the three groups were statistically significant.There was no significant difference in peak degree and variance among the three groups.The parameters with statistical difference among the three groups were selected for ROC analysis.The AUC of the 10th percentile was 0.74,the 95%confidence interval was 0.62-0.87,the sensitivity was 54.7%,and the specificity was 90.5%.The sensitivity of 90th percentile and root mean square was 73.6%.The parameters with significant difference among the three groups were selected for ROC analysis.The AUC of the 10th percentile was 0.86,95%confidence interval was 0.77-0.95,the sensitivity was 71.4%,and the specificity was 92.3%.The highest value and range specificity were 94.9%,and the highest value,root mean square value and skewness sensitivity were 85.7%.Conclusion mDixon histogram parameters are useful in the diagnosis of primary lymphedema of lower extremity.