多参数MRI纹理分析预测直肠癌患者放射治疗后早期股骨头坏死

Multi-parametric MRI texture analysis for predicting early femoral head necrosis in patients with rectal cancer after radiotherapy

目的 探讨多参数MRI(mpMRI)纹理分析预测直肠癌患者放射治疗(放疗)后早期股骨头坏死(FHN)的价值。方法 回顾性分析52例接受盆腔放疗直肠癌患者放疗前2周及放疗后3个月内的盆腔MRI,其中31例未见FHN,21例出现早期FHN(Ⅰ期16例,Ⅱ期5例)。采用3D-slicer软件基于T1WI、T2WI和弥散加权成像(DWI)分割右侧股骨头,并提取其纹理参数;对比放疗前后纹理参数,将差异有统计学意义的放疗前参数纳入多因素logistic回归分析,建立模型T1WI、模型T2WI、模型DWI及模型T1WI+T2WI+DWI。根据放疗后影像学所见行股骨头坏死骨循环研究协会(ARCO)分期,以受试者工作特征(ROC)曲线分析单一纹理参数及联合模型预测直肠癌患者放疗后早期FHN的效能。结果 T1WI及T2WI纹理参数中,放疗前股骨头能量及均匀性高于放疗后;DWI纹理参数中,放疗前股骨头能量高于、而长行程高灰度强调及短行程高灰度强调低于放疗后。上述放疗前纹理参数单一预测直肠癌患者放疗后早期FHN的曲线下面积(AUC)为0.581~0.712,模型T1WI、模型T2WI、模型DWI和模型T1WI+T2WI+DWI的AUC分别为0.660、0.713、0.770和0.853。结论 mpMRI纹理分析可有效预测直肠癌患者放疗后早期FHN。

Objective To investigate the value of multi-parametric MRI(mpMRI)texture analysis for predicting early femoral head necrosis(FHN)in rectal cancer patients after radiotherapy.Methods Pelvic MRI of 52 rectal cancer patients who underwent pelvic radiotherapy within 2 weeks before and 3 months after radiotherapy were retrospectively analyzed.Among 52 cases,21 had early FHN(16 cases of stageⅠand 5 cases of stageⅡ)but 31 cases had not.Based on T1WI,T2WI and DWI,3D-slicer software was used to segment right femoral head and extract its texture parameters.The texture parameters were compared before and after radiotherapy.Before radiotherapy texture parameters being significant different with those after radiotherapy were included in multivariate logistic regression analysis,and then model T1WI,model T2WI,model DWI and model T1WI+T2WI+DWI were established.Association Research Circulation Osseous(ARCO)staging of femoral head necrosis was performed after radiotherapy according to imaging findings.Receiver operating characteristic(ROC)curve was used to analyze the efficacy of each single texture parameter and combined model for predicting early FHN in rectal cancer patients after radiotherapy.Results Among T1WI and T2WI texture parameters,the energy and uniformity of femoral head before radiotherapy were higher than those after radiotherapy,while among diffusion weighted imaging texture parameters,the energy of femoral head before radiotherapy was higher than that after radiotherapy,and the long run high gray level emphasis and short run low gray level emphasis were lower than those after radiotherapy.The area under the curve(AUC)of the above pre-radiotherapy texture parameters for predicting early FHN in rectal cancer patients after radiotherapy were 0.581—0.712,and of model T1WI,model T2WI and model DWI model T1WI+T2WI+DWI was 0.660,0.713,0.770 and 0.853,respectively.Conclusion mpMRI texture parameters could effectively predict early femoral head necrosis in patients with rectal cancer after radiotherapy.