体素内不相干运动MRI多模型参数评估子宫内膜样腺癌微卫星不稳定状态

Assessing microsatellite instability of endometrial adenocarcinoma with multimodal intravoxel incoherent motion

目的探究体素内不相干运动(IVIM)成像单指数、双指数和拉伸指数模型参数在子宫内膜样腺癌(EA)微卫星不稳定(MSI)状态评估中的价值。方法回顾性收集经病理证实为EA的50例病人的IVIM成像资料,平均年龄(53.1±7.9)岁。根据免疫组化结果将病人分为MSI组(20例)和微卫星稳定(MSS)组(30例)。在IVIM成像各参数伪彩图上分别测量单指数模型参数[标准表观扩散系数(ADCstand)],双指数模型参数[真扩散系数(D)、伪扩散系数(D*)、灌注分数(f)]和拉伸指数模型参数[分布扩散系数(DDC)、扩散异质性指数(α)]值。采用独立样本t检验、卡方检验、Mann-WhitneyU检验比较MSI组和MSS组间一般资料及IVIM成像各参数的差异。采用受试者操作特征(ROC)曲线评估IVIM成像各参数及3种指数模型鉴别MSI状态的诊断效能,并计算其曲线下面积(AUC)。结果MSI组病人的年龄和肿瘤最大径均高于MSS组,且MSI组的ⅢA和ⅠB期病人占比高于MSS组,而ⅠA期病人占比低于MSS组(均P<0.05)。MSI组的ADCstand、D、f和DDC值均小于MSS组,α值大于MSS组(均P<0.05);2组间D*值的差异无统计学意义(P>0.05)。在单个参数中,α值的诊断效能最高,AUC值为0.777,诊断敏感度为95.00%,特异度为56.67%,ADCstand、D、DDC和f的AUC值依次减低;在3种模型中,拉伸指数模型的AUC值最高(0.855),诊断敏感度为95.00%,特异度为80.00%,其次为双指数模型和单指数模型。结论IVIM单指数、双指数及拉伸指数模型定量参数均可用于无创评估EA的MSI状态,拉伸指数模型在3种模型中的诊断效能最高。

Objective To investigate the value of monoexponential,biexponential,and stretched exponential model of intravoxel incoherent motion(IVIM)for assessing microsatellite instability(MSI)of endometrial adenocarcinoma(EA).Methods We retrospectively collected IVIM imaging data from 50 patients with pathologically confirmed EA(mean age 53.1±7.9 years).Patients were divided into MSI group(20 patients)and microsatellite stabilization(MSS)group(30 patients)based on immunohistochemistry results.We measured various parameters of the monoexponential model parameters[standard apparent diffusion coefficient(ADCstand)],biexponential model parameters[true diffusion coefficient(D),pseudo diffusion coefficient(D*),perfusion fraction(f)],and stretched exponential model parameters[distribution diffusion coefficient(DDC),diffusion heterogeneity index(α)].These parameters were evaluated on pseudo-color plots derived from IVIM data.Independent samples t-test,chi-square test,and Mann-Whitney U test were used to compare patient characteristics and differences in IVIM parameters between the MSI and MSS groups.The diagnostic efficacy of each parameter of IVIM and the three models in identifying MSI status was assessed using the area under the receiver operating characteristic(ROC)curve and the area under the curve(AUC).Results In the MSI group,patients had higher age and maximum tumor diameter,a higher proportion of stageⅢA andⅠB,and a lower proportion of stageⅠA compared to the MSS group(all P<0.05).The MSI group demonstrated significantly lower values of ADCstand,D,f,and DDC,and higher values ofαcompared to the MSS group(all P<0.05).The difference in D*values between the two groups was not statistically significant(P>0.05).Among the individual parameters,αexhibited the highest AUC value(0.777),with a diagnostic sensitivity of 95.00%and a specificity of 56.67%.The ADCstand,D,DDC,and f followed in decreasing order of AUC value.Among the three models,the stretched exponential model demonstrated the highest AUC value(0.855),with a diagnostic sensitivity of 95.00%and a specificity of 80.00%,followed by the biexponential model and the monoexponential model.Conclusion Quantitative parameters of monoexponential,biexponential,and stretched exponential model of IVIM are useful for non-invasive assessment of MSI in EA,and the stretched exponential model has the highest diagnostic performance among the three models.