基于Logistic回归判别分析原发性及继发性肺淋巴瘤临床和影像征象的研究

Clinical and Imaging Features of Primary and Secondary Pulmonary Lymphoma: Discriminant Analysis Based on Logistic Regression Method

目的建立定量评估原发性肺淋巴瘤(PPL)及继发性肺淋巴瘤(SPL)临床和影像征象的判别模型,探讨两者临床和影像征象差异。方法回顾性分析本院111例确诊为肺淋巴瘤患者的临床和影像征象,包括50例PPL和61例SPL。采用卡方检验或确切概率法比较两组临床和影像征象差异,P<0.05为有统计学意义。筛选出有统计学意义的变量,使用Logistic回归方法建立判别模型。结果B症状、血清乳酸脱氢酶(LDH)水平及分期和空气支气管征、肺裂膨隆征、支气管扩张、胸膜累及、肺门/纵隔淋巴肿大、晕征在两组分布差异有显著性。基于上述筛选变量使用Logistic回归方法获得判别函数。以判别概率绘制受试者工作特征曲线(ROC),以最佳分类临界值P=0.575为判别标准。本样本的误判率为12.6%,灵敏度为88.5%,特异度为86.0%。本组样本中分期Ⅰ+Ⅱ期与Ⅲ+Ⅳ期、空气支气管征阴性与阳性、晕征阴性与阳性、支气管扩张阴性与阳性判别为SPL的比例分数分别为0.064、3.646、0.198、7.860倍。结论分期为Ⅲ+Ⅳ期和晕征的出现提示SPL的诊断。空气支气管征、支气管扩张是PPL患者的特征性CT表现。Logistic回归判别分析可以通过临床及影像征象鉴别PPL和SPL,具有较高的临床实用价值。

Objective To establish a predictive model for quantitative assessment of primary and secondary pulmonary lymphoma and to compare the characteristics between groups.Methods A total of 111 patients with pulmonary lymphoma diagnosed from 2004 to 2018 were retrospectively reviewed.There were 24 males and 26 females with a median age of 56 years in 50 cases of primary pulmonary lymphoma(PPL)patients,and 40 males and 21 females with a median age of 59 years in 61 cases of secondary pulmonary lymphoma(SPL)patients.The clinical features included symptoms(asymptomatic,B symptoms and respiratory symptoms),serum lactate dehydrogenase(LDH)level and stage.Two experienced radiologists evaluated the patterns and characteristics of CT findings.χ2 tests or Fisher’s exact tests were performed for the comparison of the differences in clinical features and imaging findings between groups.The significant variables were further applied to discrimination between PPL and SPL based on Logistic regression analysis.P value on the left side of the inflection point of the ROC curve according to discrimination probability was used as a criterion to discriminate between PPL and SPL.Results Logistic discriminant function for prediction of PPL and SPL was Logit P=-0.746-0.125 B-symptoms(without=0,with=1)-0.502 LDH level(normal=0,elevated=1)-2.744 stage(Ⅰ+Ⅱ=0,Ⅲ+Ⅳ=1)+0.296 number(single=0,multiple=1)+1.294 air bronchogram(without=0,with=1)-1.618 halo sign(without=0,with=1)+1.669 bulging fissure sign(without=0,with=1)+2.062 bronchiectasis(without=0,with=1)-0.868 pleural involvement(without=0,with=1)-0.347 hilar/mediastinal lymphadenopathy(without=0,with=1).P=0.575 was used as a criterion.The false positive rate was 12.6%,the sensitivity was 88.5%,and the specificity was 86.0%.In this sample,the rations of the number of SPL patients who were stagedⅠ+ⅡandⅢ+Ⅳ,and without and with air bronchogram,halo sign,and bronchiectasis were 0.064,and 3.646,0.198 and 7.860,respectively.Conclusion Patients who are stagedⅢ+Ⅳand show halo sign suggest the diagnosis of SPL.Air bronchogram and bronchiectasis are characteristic CT findings of PPL patients.The Discriminant Analysis based on Logistic regression method can be used as a prediction method of PPL and SPL,which has a high clinical value.