Liu Bo, Li Chunhai, Sun Xiaorong, Zhou Wei, Sun Jing, Liu Hong, Li Shuying, Jia Haipeng, Xing Ligang, Dong Xinzhe
Department of Radiology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
Department of Radiology, Shandong Cancer Hospital and Institute, Jinan, China.
Front Oncol. 2021 Nov 3;11:615174. doi: 10.3389/fonc.2021.615174. eCollection 2021.
To retrospectively observe the instantaneous changes in intratumor density heterogeneity after microwave ablation (MWA) of lung tumors and to determine their prognostic value in predicting treatment response and local tumor progression (LTP).
Pre- and post-MWA computed tomography (CT) images of 50 patients (37-males; 13-females; mean-age 65.9 ± 9.7y, 39 primary and 11 metastasis) were analyzed to evaluate changes in intratumor density. Global, regional, and local scale radiomics features were extracted to assess intratumor density heterogeneity. In four to six weeks, chest enhanced CT was used as the baseline evaluation of treatment response. The correlations between the parametric variation immediately after ablation and the visual score of ablation response (Rvisu) were analyzed by nonparametric Spearman correlation analysis. The 1-year LTP discrimination power was assessed using the area under the receiver operating characteristic (ROC) curves. A Cox proportional hazards regression model was used to identify the independent prognostic features.
Although no significant volume changes were observed after ablation, the radiomics parameters changed in different directions and degrees. The mean intensity value from baseline CT image was 30.3 ± 23.2, and the post-MWA CT image was -60.9 ± 89.8. The ratio of values change was then calculated by a unified formulation. The largest increase (522.3%) was observed for cluster prominence, while the mean CT value showed the largest decline (321.4%). The pulmonary tumors had a mean diameter of 3.4 ± 0.8 cm. Complete ablation was documented in 36 patients. Significant correlations were observed between Rvisu and quantitative features. The highest correlations were observed for changes in local features after MWA, with r ranging from 0.594 to 0.782. LTP developed in 22 patients. The Cox regression model revealed Δcontrast% and response score as independent predictors (Δcontrast%: odds ratio [OR]=5.61, p=0.001; Rvisu: OR=1.73, p=0019). ROC curve analysis showed that Δcontrast% was a better predictor of 1-year LTP. with higher sensitivity (83.5% vs. 71.2%) and specificity (87.1% vs. 76.8%) than those for Rvisu.
The changes in intratumor density heterogeneity after MWA could be characterized by analysis of radiomics features. Real-time density changes could predict treatment response and LTP in patients with pulmonary tumors earlier, especially for tumors with larger diameters.
回顾性观察肺肿瘤微波消融（MWA）后瘤内密度异质性的即时变化，并确定其在预测治疗反应和局部肿瘤进展（LTP）方面的预后价值。
分析50例患者（37例男性；13例女性；平均年龄65.9±9.7岁，39例原发性肿瘤和11例转移瘤）MWA前后的计算机断层扫描（CT）图像，以评估瘤内密度变化。提取全局、区域和局部尺度的放射组学特征，以评估瘤内密度异质性。在4至6周时，使用胸部增强CT作为治疗反应的基线评估。通过非参数Spearman相关分析，分析消融后立即出现的参数变化与消融反应视觉评分（Rvisu）之间的相关性。使用受试者操作特征（ROC）曲线下面积评估1年LTP的判别能力。采用Cox比例风险回归模型确定独立的预后特征。
尽管消融后未观察到明显的体积变化，但放射组学参数在不同方向和程度上发生了变化。基线CT图像的平均强度值为30.3±23.2，MWA后CT图像的平均强度值为-60.9±89.8。然后通过统一公式计算值变化的比率。聚类突出度增加最大（522.3%），而平均CT值下降最大（321.4%）。肺肿瘤的平均直径为3.4±0.8 cm。36例患者记录为完全消融。观察到Rvisu与定量特征之间存在显著相关性。MWA后局部特征变化的相关性最高，r范围为0.594至0.782。22例患者发生LTP。Cox回归模型显示Δ对比度%和反应评分是独立预测因子（Δ对比度%：比值比[OR]=5.61，p=0.001；Rvisu：OR=1.73，p=0.019）。ROC曲线分析表明，Δ对比度%是1年LTP的更好预测因子，其敏感性（83.5%对71.2%）和特异性（87.1%对76.8%）均高于Rvisu。
MWA后瘤内密度异质性的变化可通过放射组学特征分析来表征。实时密度变化可更早地预测肺肿瘤患者的治疗反应和LTP，尤其是对于直径较大的肿瘤。
