T2 mapping预测直肠癌脉管侵犯的初步研究

Preliminary study on the value of T2 mapping in predicting lymphovascular invasion of rectal cancer

目的探讨T2 mapping定量参数预测直肠癌脉管侵犯(lymphovascular invasion,LVI)的价值。材料与方法回顾性分析2019年10月至2021年11月于大连医科大学附属第一医院行3.0 T MRI扫描的34例直肠癌患者资料,分为LVI组(A组)13例与非LVI组(B组)21例。扫描序列包括T1WI、T2WI、扩散加权成像及T2 mapping等。结合以上序列图像定位病灶,并由2名观察者于T2 mapping图像显示肠壁最厚层面放置三个感兴趣区(region of interest,ROI)测量T2值。采用Bland-Altman曲线检验2名观察者测量值的一致性。根据数据符合正态性分布与否,采用独立样本t检验或Mann-Whitney U检验比较两组T2值的差异。结果2名观察者测量的T2值一致性良好,表现为Bland-Altman图中的点均匀分布在+1.96至-1.96倍标准线差内。A组和B组的T2值分别为(77.15±6.95)ms、(87.06±7.55)ms,A组低于B组,差异具有统计学意义(P<0.05);T2值预测直肠癌LVI的曲线下面积、阈值、敏感度及特异度分别为0.861、83.19 ms、84.62%及76.19%。结论T2 mapping在预测LVI方面具有较好的价值。

Objective:To investigate the value of T2 mapping quantitative parameters in predicting lymphovascular invasion(LVI)and non-LVI of rectal cancer.Materials and methods:A retrospective analysis of 34 cases with rectal cancer who underwent 3.0 T MRI scans in the First Affiliated Hospital of Dalian Medical University from October 2019 to November 2021 was divided into a LVI group(group A)of 13 cases and a non-LVI group(group B)of 21 cases.Scanning sequences include T1WI,T2WI,diffusion weighted imaging(DWI),and T2 mapping.Combined with the above sequence images,the lesions were located,and two observers placed three region of interest(ROIs)to measure the T2 value on the largest slice of the lesion displayed on the T2 mapping image.A Bland-Altman curve was used to test the agreement of the 2 observers’measurements.According to whether the data conformed to the normal distribution or not,independent samples t-test or Mann-Whitney U test was used to compare the difference of T2 value between rectal cancer group A and group B.Results:T2 mapping parameters measured by the two observers were in consistent,and most of the scattered points in the Bland-Altman graph were evenly distributed between the+1.96 and-1.96 standard lines.The T2 values of group A and group B were(77.15±6.95)ms and(87.06±7.55)ms,respectively.Group A was lower than group B,and the difference was statistically significant(P<0.05);the area under the curve(AUC),threshold,sensitivity and specificity of T2 value in predicting LVI were 0.861,83.19 ms,84.62%and76.19%,respectively.Conclusions:T2 mapping has high value in predicting LVI of rectal cancer.