软组织肉瘤MRI影像学特征与Ki-67表达水平的相关性研究

Assessment of MRI features correlating with Ki-67 labeling index in soft tissue sarcoma

目的:探讨软组织肉瘤MRI影像特征与其Ki-67表达水平的相关性。方法:搜集48例临床或影像疑似软组织肉瘤的患者,均行3.0T MRI扫描,扫描序列包括常规T_(1)WI平扫、T_(2)WI平扫及T_(1)WI增强扫描,其中25例行扩散加权成像(DWI)检查。由2位影像诊断医师评估常规影像学特征,同时测量病变区域的ADC平均值(ADCmean)及ADC最小值(ADCmin)。Ki-67≥30%为高表达组,Ki-67<30%为低表达组。采用受试者工作特征(ROC)曲线评估软组织肉瘤各影像学特征对Ki-67高表达与低表达的鉴别诊断效能。结果:48例软组织肉瘤中22例Ki-67低表达,26例Ki-67高表达。瘤周强化鉴别诊断Ki-67高表达与Ki-67低表达的曲线下面积(AUC)为0.855,敏感度与特异度分别为85%、86%;平扫T_(2)信号不均匀性(≥50%)鉴别诊断Ki-67高表达与Ki-67低表达的AUC为0.710,敏感度与特异度分别为69%、72%;肿瘤边界鉴别诊断Ki-67高表达与Ki-67低表达的AUC为0.692,敏感度与特异度分别为77%、56%。软组织肉瘤Ki-67高表达组与Ki-67低表达组的ADCmean值、ADCmin值差异均有统计学意义(P<0.05),且Ki-67高表达组的ADCmean值、ADCmin值均低于Ki-67低表达组,ADCmean值、ADCmin值与其Ki-67表达水平均呈负相关。ADCmean阈值为1.332×10^(-3)mm^(2)/s时,敏感度与特异度分别为85%、73%;ADCmin阈值为0.883×10^(-3)mm^(2)/s时,敏感度与特异度分别为89%、78%。结论:软组织肉瘤的常规影像学特征中瘤周强化、T_(2)信号不均匀性、肿瘤边界与其Ki-67表达水平相关,其中瘤周强化的诊断效能最高。ADCmean及ADCmin值可用于鉴别软组织肉瘤Ki-67高表达与Ki-67低表达。

Objective:To examine the correlation of MRI features with Ki-67 labeling index(LI)in soft tissue sarcoma(STS).Methods:Forty-eight patients with clinically diagnosed STS in our hospital underwent 3.0T MRI,including T_(1)WI,T_(2)WI,enhanced T_(1)WI examination and 25 patients underwent diffusion-weighted imaging(DWI).The conventional MRI features,mean and minimum apparent diffusion coefficients(ADCs)(ADCmean and ADCmin,respectively)of each lesion were independently analyzed by two readers.STS were considered high-proliferation if≥30%of nuclei were stained while low-proliferation if<30%of nuclei were stained.Their relationship with the Ki-67 LI was examined using ROC analyses.Results:Among 48 lesions,22 and 26 were categorized into the low-and high-proliferation groups,respectively.Three MRI features,including peritumoral enhancement,margin definitions and heterogeneous signal intensities greater than or equal to 50%at T_(2)-weighted imaging,were associated with Ki-67 LI.The sensitivity,specificity,and area under the curve of peritumoral enhancement for differentiating low-and high-proliferation groups were 85%,86%,and 0.855.The sensitivity,specificity,and area under the curve of heterogeneous signal intensities greater than or equal to 50%at T_(2)-weighted imaging for differentiating low-and high-proliferation groups were 69%,72%,and 0.710.The sensitivity,specificity,and area under the curve of Margin definitions for differentiating low-and high-proliferation groups were 77%,56%,and 0.692.A statistical difference between ADCmean and ADCmin was found in high-proliferation group and low-proliferation group.The ADCmean and ADCmin of the high-proliferation group were significantly lower than that of the low-proliferation group.A cut-off ADCmean value of 1.332×10^(-3)mm^(2)/s was used,the sensitivity and specificity for differentiating low-and high-proliferation groups were 85%,73%.A cut-off ADCmin value of 0.883×10^(-3)mm^(2)/s was used,the sensitivity and specificity for differentiating low-and high-proliferation groups were 89%,78%.Conclusion:Peritumoral enhancement,heterogeneous signal intensities greater than or equal to 50%at T_(2)-weighted imaging and Margin definitions were associated with Ki-67 LI,and Peritumoral enhancement was with the best diagnostic performance.ADCmean and ADCmin were correlated with Ki-67 LI and could help differentiate STS with low or high proliferation potential.