纹理分析作为直肠癌患者新辅助放化疗肿瘤反应的成像生物标志物，采用3-T磁共振进行研究。

Texture analysis as imaging biomarker of tumoral response to neoadjuvant chemoradiotherapy in rectal cancer patients studied with 3-T magnetic resonance.

作者信息

De Cecco Carlo N, Ganeshan Balaji, Ciolina Maria, Rengo Marco, Meinel Felix G, Musio Daniela, De Felice Francesca, Raffetto Nicola, Tombolini Vincenzo, Laghi Andrea

机构信息

From the *Department of Radiological Sciences, Oncology, and Pathology, University of Rome "Sapienza"-Polo Pontino, Latina, Italy; †Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston; ‡Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Falmer, Sussex, England; §Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany; and ∥Department of Radiotherapy, University of Rome "Sapienza", Rome, Italy.

出版信息

Invest Radiol. 2015 Apr;50(4):239-45. doi: 10.1097/RLI.0000000000000116.

DOI:10.1097/RLI.0000000000000116

PMID:25501017

Abstract

OBJECTIVE

The aim of this study was to determine whether texture features of rectal cancer on T2-weighted (T2w) magnetic resonance images can predict tumoral response in patients treated with neoadjuvant chemoradiotherapy (CRT).

MATERIALS AND METHODS

We prospectively enrolled 15 consecutive patients (6 women, 63.2 ± 13.4 years) with rectal cancer, who underwent pretreatment and midtreatment 3-T magnetic resonance imaging. Treatment protocol consisted of neoadjuvant CRT with oxaliplatin and 5-fluorouracile. Texture analysis using a filtration-histogram technique was performed using a commercial research software algorithm (TexRAD Ltd, Somerset, England, United Kingdom) on unenhanced axial T2w images by manually delineating a region of interest around the tumor outline for the largest cross-sectional area. The technique selectively filters and extracts textures at different anatomic scales followed by quantification of the histogram using kurtosis, entropy, skewness, and mean value of positive pixels. After CRT, all patients underwent complete surgical resection and the surgical specimen served as the gold standard.

RESULTS

Six patients showed pathological complete response (pCR), and 4 patients, partial response (PR). Five patients were classified as nonresponders (NRs). Pretreatment medium texture-scale quantified as kurtosis was significantly lower in the pCR subgroup in comparison with the PR + NR subgroup (P = 0.01). Midtreatment kurtosis without filtration was significantly higher in pCR in comparison with PR + NR (P = 0.045). The change in kurtosis between midtreatment and pretreatment images was significantly lower in the PR + NR subgroup compared with the pCR subgroup (P = 0.038). Pretreatment area under the receiver operating characteristic curves, to discriminate between pCR and PR + NR, was significantly higher for kurtosis (0.907, P < 0.001) compared with all other parameters. The optimal cutoff value for pretreatment kurtosis was 0.19 or less. Using this value, the sensitivity and specificity for pCR prediction were 100% and 77.8%, respectively.

CONCLUSION

Texture parameters derived from T2w images of rectal cancer have the potential to act as imaging biomarkers of tumoral response to neoadjuvant CRT.

摘要

目的

本研究旨在确定直肠癌在T2加权（T2w）磁共振图像上的纹理特征是否能够预测接受新辅助放化疗（CRT）患者的肿瘤反应。

材料与方法

我们前瞻性纳入了15例连续的直肠癌患者（6例女性，年龄63.2±13.4岁），这些患者在治疗前和治疗中期接受了3-T磁共振成像检查。治疗方案包括使用奥沙利铂和5-氟尿嘧啶进行新辅助CRT。使用商业研究软件算法（TexRAD Ltd，英国萨默塞特），通过在未增强的轴向T2w图像上手动勾勒肿瘤轮廓最大横截面积周围的感兴趣区域，采用过滤-直方图技术进行纹理分析。该技术在不同解剖尺度上选择性过滤并提取纹理，随后使用峰度、熵、偏度和正像素的平均值对直方图进行量化。CRT后，所有患者均接受了完整的手术切除，手术标本作为金标准。

结果

6例患者显示病理完全缓解（pCR），4例患者显示部分缓解（PR）。5例患者被归类为无反应者（NRs）。与PR+NR亚组相比，pCR亚组中治疗前中等纹理尺度（以峰度量化）显著更低（P=0.01）。与PR+NR相比，pCR组中未进行过滤的治疗中期峰度显著更高（P=0.045）。与pCR亚组相比，PR+NR亚组中治疗中期与治疗前图像之间峰度的变化显著更低（P=0.038）。与所有其他参数相比，用于区分pCR和PR+NR的治疗前受试者操作特征曲线下面积，峰度显著更高（0.907，P<0.001）。治疗前峰度的最佳截断值为0.19或更低。使用该值，预测pCR的敏感性和特异性分别为100%和77.8%。