基于读出分段回波平面成像的扩散加权成像在评估局部晚期直肠癌新辅助放化疗后肿瘤反应中的作用。
The role of readout-segmented echo-planar imaging-based diffusion-weighted imaging in evaluating tumor response of locally advanced rectal cancer after neoadjuvant chemoradiotherapy.
作者信息
Yang Lanqing, Xia Chunchao, Liu Dan, Fang Xin, Pan Xuelin, Ma Ling, Wu Bing
机构信息
Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, PR China.
GE Healthcare, Shanghai, PR China.
出版信息
Acta Radiol. 2020 Sep;61(9):1155-1164. doi: 10.1177/0284185119897354. Epub 2020 Jan 10.
BACKGROUND
Accurate assessment of tumor response in rectal cancer could help individualize treatment.
PURPOSE
To evaluate the role of diffusion-weighted imaging (DWI) based on readout-segmented echo-planar imaging (rs-EPI) in assessing tumor response after neoadjuvant chemoradiotherapy (CRT) in locally advanced rectal cancer (LARC).
MATERIAL AND METHODS
Sixty-three patients with LARC who received neoadjuvant CRT and surgery were enrolled retrospectively. They all underwent pre- and post-CRT magnetic resonance examinations, including DWI using rs-EPI. According to pathological results, patients were grouped as pathological complete responder (pCR, n = 16) and non-pCR (n = 47). Visual assessment of residual tumor and whole-tumor histogram analysis of pre- and post-CRT apparent diffusion coefficient (ADC) map was performed by two radiologists; tumor volume on ADC map was also recorded.
RESULTS
Overall inter-observer agreement was good for histogram analysis (ICC = 0.543-0.999). Tumor volume reduction rate on ADC map showed no significant difference between the two groups ( = 0.468). Post-CRT mean, quantile values, and their percentage changes were higher in the pCR group (all < 0.001). Post-CRT mean value had a good diagnostic power in selecting pCR (AUC = 0.855), with a cut-off value of 1.345 × 10 mm/s, yielding a sensitivity of 83%, specificity of 81.3%. Post-CRT 95% quantile value had the highest AUC (AUC = 0.868) among quantile values, and a higher specificity (87.5% vs. 81.3%) than mean value with comparable overall diagnostic performance ( = 0.563). Visual assessment showed a sensitivity of 85.1%, specificity of 68.8% in selecting pCR.
CONCLUSION
Quantitative ADC value of rs-EPI DWI could reliably evaluate tumor response in patients with LARC. Post-CRT 95% quantile ADC value could help mean value to more accurately identify pCR.
背景
准确评估直肠癌的肿瘤反应有助于实现个体化治疗。
目的
评估基于读出分段回波平面成像（rs-EPI）的扩散加权成像（DWI）在评估局部晚期直肠癌（LARC）新辅助放化疗（CRT）后肿瘤反应中的作用。
材料与方法
回顾性纳入63例接受新辅助CRT及手术的LARC患者。他们均在CRT前后接受了磁共振检查，包括使用rs-EPI的DWI。根据病理结果，将患者分为病理完全缓解者（pCR，n = 16）和非pCR（n = 47）。由两名放射科医生对残余肿瘤进行视觉评估，并对CRT前后的表观扩散系数（ADC）图进行全肿瘤直方图分析；同时记录ADC图上的肿瘤体积。
结果
观察者间总体一致性在直方图分析方面良好（ICC = 0.543 - 0.999）。两组间ADC图上的肿瘤体积缩小率无显著差异（ = 0.468）。CRT后，pCR组的平均、分位数数值及其百分比变化更高（均 < 0.001）。CRT后的平均值在选择pCR方面具有良好的诊断效能（AUC = 0.855），截断值为1.345×10⁻³ mm²/s，灵敏度为83%，特异性为81.3%。CRT后的95%分位数数值在各分位数数值中AUC最高（AUC = 0.868），且与平均值相比特异性更高（87.5%对81.3%），总体诊断性能相当（ = 0.563）。视觉评估在选择pCR方面的灵敏度为85.1%，特异性为68.8%。
结论
rs-EPI DWI的定量ADC值能够可靠地评估LARC患者的肿瘤反应。CRT后的95%分位数ADC值有助于平均值更准确地识别pCR。
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