Aker Medhat, Ganeshan Balaji, Afaq Asim, Wan Simon, Groves Ashley M, Arulampalam Tan
Department of General Surgery, Colchester General Hospital, Colchester, United Kingdom.
Institute of Nuclear Medicine, University College London Hospitals, London, United Kingdom.
Dis Colon Rectum. 2019 Feb;62(2):163-170. doi: 10.1097/DCR.0000000000001224.
A certain proportion of patients with locally advanced rectal cancer experience complete response after undergoing neoadjuvant chemoradiotherapy. These patients might be suitable for a conservative "watch and wait" approach, avoiding high-morbidity surgery. Texture analysis is a new modality that can assess heterogeneity in medical images by statistically analyzing gray-level intensities on a pixel-by-pixel basis. This study hypothesizes that texture analysis of magnetic resonance images can identify patients with a complete response.
This study aims to determine whether texture analysis of magnetic resonance images as a quantitative imaging biomarker can accurately identify patients with complete response.
This is a retrospective diagnostic accuracy study.
This study was conducted at Colchester General Hospital, January 2003 to 2014.
All patients diagnosed with locally advanced rectal cancer who underwent long-course chemoradiotherapy had a posttreatment magnetic resonance scan and underwent surgery are included.
Texture analysis was extracted from T2-weighted magnetic resonance images of the rectal cancer.
Textural features that are able to identify complete responders were identified by a Mann-Whitney U test. Their diagnostic accuracy in identifying complete responders was determined by the area under the receiver operator characteristics curve. Cutoff values were determined by the Youden index. Pathology was the standard of reference.
One hundred fourteen patients with first posttreatment MRI scans (6.2 weeks after completion of neoadjuvant treatment) were included. Sixty-eight patients had a second posttreatment scan (10.4 weeks). With no filtration, mean (p = 0.033), SD (p = 0.048), entropy (p = 0.007), and skewness (p = 0.000) from first posttreatment scans, and SD (p = 0.042), entropy (p = 0.014), mean of positive pixels (p = 0.032), and skewness (p = 0.000) from second posttreatment scans were all able to identify complete response. Area under the curve ranged from 0.750 to 0.88.
Texture analysis of MRI is a new modality; therefore, further studies are necessary to standardize the methodology of extraction of texture features, timing of scans, and acquisition parameters.
Texture analysis of MRI is a potentially significant imaging biomarker that can accurately identify patients who have experienced complete response and might be suitable for a nonsurgical approach. (Cinicaltrials.gov:NCT02439086). See Video Abstract at http://links.lww.com/DCR/A760.
一定比例的局部晚期直肠癌患者在接受新辅助放化疗后会出现完全缓解。这些患者可能适合采用保守的“观察等待”方法，避免进行高风险手术。纹理分析是一种新的方法，可通过逐像素统计分析灰度强度来评估医学图像中的异质性。本研究假设磁共振图像的纹理分析能够识别出完全缓解的患者。
本研究旨在确定磁共振图像的纹理分析作为一种定量成像生物标志物能否准确识别完全缓解的患者。
这是一项回顾性诊断准确性研究。
本研究于2003年1月至2014年在科尔切斯特综合医院进行。
纳入所有诊断为局部晚期直肠癌且接受了长程放化疗、治疗后进行了磁共振扫描并接受手术的患者。
从直肠癌的T2加权磁共振图像中提取纹理分析。
通过曼-惠特尼U检验确定能够识别完全缓解者的纹理特征。通过受试者操作特征曲线下面积确定其识别完全缓解者的诊断准确性。通过约登指数确定临界值。病理检查为参考标准。
纳入114例首次治疗后磁共振扫描的患者（新辅助治疗完成后6.2周）。68例患者进行了第二次治疗后扫描（10.4周）。在未进行滤波的情况下，首次治疗后扫描的均值（p = 0.033）、标准差（p = 0.048）、熵（p = 0.007）和偏度（p = 0.000），以及第二次治疗后扫描的标准差（p = 0.042）、熵（p = 0.014）、阳性像素均值（p = 0.032）和偏度（p = 0.000）均能够识别完全缓解。曲线下面积范围为0.750至0.88。
磁共振成像的纹理分析是一种新方法；因此，需要进一步研究来规范纹理特征提取方法、扫描时间和采集参数。
磁共振成像的纹理分析是一种潜在的重要成像生物标志物，能够准确识别经历完全缓解且可能适合非手术治疗方法的患者。（Clinicaltrials.gov:NCT02439086）。见视频摘要：http://links.lww.com/DCR/A760 。
