Objective To observe changes of plain MR T1WI signal intensity of dentate nucleus in nasopharyngeal carcinoma patients after radiotherapy and multiple times of intravenous injection of gadolinium-based contrast agent(...Objective To observe changes of plain MR T1WI signal intensity of dentate nucleus in nasopharyngeal carcinoma patients after radiotherapy and multiple times of intravenous injection of gadolinium-based contrast agent(GBCA).Methods Fifty patients with pathologically confirmed nasopharyngeal carcinoma and received intensity-modulated radiotherapy were retrospectively enrolled as the nasopharyngeal carcinoma group,and 50 patients with other malignant tumors and without history of brain radiotherapy were retrospectively enrolled as the control group.All patients received yearly GBCA enhanced MR examinations for the nasopharynx or the head.T1WI signal intensities of the dentate nucleus and the pons on same plane were measured based on images in the year of confirmed diagnosis(recorded as the first year)and in the second to the fifth years.T1WI signal intensity ratio of year i(ranging from 1 to 5)was calculated with values of dentate nucleus divided by values of the pons(ΔSI i),while the percentage of relative changes of year j(ranging from 2 to 5)was calculated withΔSI j compared toΔSI 1(Rchange j).The values of these two parameters were compared,and the correlation ofΔSI and GBCA injection year-time was evaluated within each group.Results No significant difference of gender,age norΔSI 1 was found between groups(all P>0.05).The second to the fifth yearΔSI and Rchange in nasopharyngeal carcinoma group were all higher than those in control group(all P<0.05).Within both groups,ΔSI was positively correlated with GBCA injection year-time(both P<0.05).Conclusion Patients with nasopharyngeal carcinoma who underwent radiotherapy and multiple times of intravenous injection of GBCA tended to be found with gradually worsening GBCA deposition in dentate nucleus,for which radiotherapy might be a risk factor.展开更多
文摘目的:探讨SHAP值在极端梯度提升(Extreme gradient boosting,XGBoost)MRI模型中鉴别腮腺恶性肿瘤(Malignant tumor,MT)与Warthin瘤(Warthin tumor,WT)的价值。方法:回顾分析经手术病理证实的22例22枚MT和38例51枚WT的MRI资料,分析瘤体形态、位置和强化方式,以及T_(1)WI、T_(2)WI、FS-T_(1)WI、FS-T_(2)WI影像征象,经单因素分析筛选有统计学意义的征象,纳入XGBoost模型,使用受试者工作特征曲线下面积(Area under the curve,AUC)、敏感度、特异度评价模型诊断效能。通过可解释机器学习模型(Shapley additive explanations,SHAP)值对模型进行分析,明确各MRI征象在模型中的权重。结果:22枚MT和51枚WT中,持续性强化(P<0.05)、形态不规则(χ^(2)=20.707,P<0.05)、非尾叶(χ^(2)=8.911,P<0.05)、T_(2)WI高信号(χ^(2)=7.581,P<0.05)、FS-T_(1)WI等低信号(P<0.05)、FS-T_(2)WI高信号(χ^(2)=9.016,P<0.05)对鉴别两者有统计学意义,且均更常见于MT中。将6项单因素纳入XGBoost模型分析得出AUC为0.847,敏感度为77.3%,特异度为92.2%;6种MRI征象绝对平均SHAP值为0.21~0.99,其中形态不规则权重最大。结论:形态不规则、T_(2)WI高信号、持续性强化、FS-T_(2)WI高信号、非尾叶、FS-T_(1)WI等低信号对MT和WT鉴别的权重存在差异,对各MRI征象的准确识别,有利于对两者精准诊断。
文摘Objective To observe changes of plain MR T1WI signal intensity of dentate nucleus in nasopharyngeal carcinoma patients after radiotherapy and multiple times of intravenous injection of gadolinium-based contrast agent(GBCA).Methods Fifty patients with pathologically confirmed nasopharyngeal carcinoma and received intensity-modulated radiotherapy were retrospectively enrolled as the nasopharyngeal carcinoma group,and 50 patients with other malignant tumors and without history of brain radiotherapy were retrospectively enrolled as the control group.All patients received yearly GBCA enhanced MR examinations for the nasopharynx or the head.T1WI signal intensities of the dentate nucleus and the pons on same plane were measured based on images in the year of confirmed diagnosis(recorded as the first year)and in the second to the fifth years.T1WI signal intensity ratio of year i(ranging from 1 to 5)was calculated with values of dentate nucleus divided by values of the pons(ΔSI i),while the percentage of relative changes of year j(ranging from 2 to 5)was calculated withΔSI j compared toΔSI 1(Rchange j).The values of these two parameters were compared,and the correlation ofΔSI and GBCA injection year-time was evaluated within each group.Results No significant difference of gender,age norΔSI 1 was found between groups(all P>0.05).The second to the fifth yearΔSI and Rchange in nasopharyngeal carcinoma group were all higher than those in control group(all P<0.05).Within both groups,ΔSI was positively correlated with GBCA injection year-time(both P<0.05).Conclusion Patients with nasopharyngeal carcinoma who underwent radiotherapy and multiple times of intravenous injection of GBCA tended to be found with gradually worsening GBCA deposition in dentate nucleus,for which radiotherapy might be a risk factor.
