MRI灰度直方图分析在眶区黑色素瘤复发的风险评估

Evaluation of Recurrence Risk of Melanoma in Orbital Area by MRI Gray Histogram Analysis

目的探讨MR常规序列灰度直方图分析对眶区黑色素瘤(OM)复发的风险评估。方法回顾性分析经病理证实的40例OM,术后随访时间为0.5~6.0年,依据是否复发分为复发组和无复发组,使用Mazda软件在常规MR序列图像上勾画提取ROI并进行灰度直方图分析,对两组病变直方图参数进行统计学分析,比较两组病变差异有统计学意义的特征参数,绘制其ROC曲线,评价其对OM复发风险的诊断效果。结果在平扫T1WI、T2WI、DWI及T1WI矢状增强四个序列灰度直方图分别提取的9个特征性参数中,T1WI直方图的9组病变参数差异均有统计学意义,其中第50百分位数诊断价值较大,ROC为0.985,最佳临界值为1267,敏感度为100%,特异度为88.46%;T2WI直方图其中2组病变参数差异有统计学意义,其中方差诊断价值较大,ROC为0.755,最佳临界值为12152,敏感度为100%,特异度为57.69%;DWI直方图其中5组病变参数差异有统计学意义,其中方差诊断价值较大,ROC为0.885,最佳临界值为10489,敏感度为92.86%,特异度为84.62%;T1WI增强直方图其中2组病变参数差异有统计学意义,其中方差鉴别价值较大,ROC为0.876,最佳临界值为36282,敏感度为92.86%,特异度为76.92%。结论常规MR序列图像灰度直方图可以作为OM复发风险评估的重要辅助手段,其中T1WI、DWI及T1WI增强直方图在鉴别肿瘤复发中的价值较高。

Objective To explore the risk assessment of recurrence of orbital melanoma by MR routine gray-scale histogram analysis.Methods A retrospective analysis of 40 cases of orbital melanoma confirmed by pathology was performed.The follow-up time was 0.5 to 6.0 years after operation.They were divided into recurrent group and non-recurrent group according to whether they recurred or not.Mazda software was used to draw ROI on conventional MR sequence images.A gray-scale histogram analysis was performed.The histogram parameters of the two groups of lesions were statistically analyzed.The characteristic parameters with statistically significant differences between the two groups were compared.The ROC curve was drawn to evaluate its diagnostic effect on the risk of recurrence of orbital melanoma.Results Among the 9 characteristic parameters extracted from four sequences of plain T1WI,T2WI,DWI and T1WI sagittal enhancement,there were significant differences in nine pathological parameters of T1WI histogram,among which the 50th percentile was of great diagnostic value,and ROC was 0.985,The optimal critical value was 1267,the sensitivity was 100%,and the specificity was 88.46%.There was a significant difference in pathological parameters between the two groups on T2WI histogram,in which ROC was 0.755,the best critical value was 12152,sensitivity was 100%,specificity was 57.69%,and the diagnostic value of variance was 0.755,the optimal critical value was 12152,the sensitivity was 100%and the specificity was 57.69%.There was significant difference in pathological parameters among the five groups on DWI histogram,in which ROC was 0.885,the best critical value was 10489,sensitivity was 92.86%and specificity was 84.62%.The diagnostic value of variance was 0.885,the optimal critical value was 10489,sensitivity was 92.86%and specificity was 84.62%.T1WI enhanced histogram showed significant difference in pathological parameters between the two groups,in which ROC was 0.876,the optimal critical value was 36282,the sensitivity was 92.86%,and the specificity was 76.92%.Conclusion The gray-scale histogram of conventional MR sequence can be used as an important auxiliary method to evaluate the risk of melanoma recurrence in orbital region.Among them,T1WI,DWI and T1WI-enhanced histogram are of high value in differentiating tumor recurrence.