Martens Milou H, Lambregts Doenja M J, Papanikolaou Nickolas, Alefantinou Styliani, Maas Monique, Manikis Georgios C, Marias Kostantinos, Riedl Robert G, Beets Geerard L, Beets-Tan Regina G H
Department of Radiology, Maastricht University Medical Center, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.
Eur Radiol. 2016 Feb;26(2):390-7. doi: 10.1007/s00330-015-3856-3. Epub 2015 Jun 12.
Single-slice magnetization transfer (MT) imaging has shown promising results for evaluating post-radiation fibrosis. The study aim was to evaluate the value of multislice MT imaging to assess tumour response after chemoradiotherapy by comparing magnetization transfer ratios (MTR) with histopathological tumour regression grade (TRG).
Thirty patients with locally advanced rectal cancer (cT3-4 and/or cN2) underwent routine restaging MRI 8 weeks post-chemoradiotherapy, including multislice MT-sequence, covering the entire tumour bed. Two independent readers delineated regions of interest on MTR maps, covering all potential remaining tumour and fibrotic areas. Mean MTR and histogram parameters (minimum, maximum, median, standard deviation, skewness, kurtosis, and 5-30-70-95th percentiles) were calculated. Reference standard was histological TRG1-2 (good response) and TRG3-5 (poor response).
24/30 patients were male; mean age was 67.7 ± 10.8 years. Mean MTR rendered AUCs of 0.65 (reader1) and 0.87 (reader2) to differentiate between TRG1-2 versus TRG3-5. Best results were obtained for 95(th) percentile (AUC 0.75- 0.88). Interobserver agreement was moderate (ICC 0.50) for mean MTR and good (ICC 0.80) for 95(th) percentile.
MT imaging is a promising tool to assess tumour response post-chemoradiotherapy in rectal cancer. Particularly, 95(th) percentile results in AUCs up to 0.88 to discriminate a good tumour response.
• The mean MTR can differentiate between good and poor responders after chemoradiation. • In addition to measurement of the mean value, histogram analyses can be beneficial. • The histogram parameter 95 (th) percentile can reach AUCs of 0.75-0.88.
单层磁化传递（MT）成像在评估放射后纤维化方面已显示出有前景的结果。本研究的目的是通过比较磁化传递率（MTR）与组织病理学肿瘤消退分级（TRG）来评估多层MT成像在评估放化疗后肿瘤反应中的价值。
30例局部晚期直肠癌（cT3 - 4和/或cN2）患者在放化疗后8周接受了常规的重新分期MRI检查，包括多层MT序列，覆盖整个肿瘤床。两名独立的阅片者在MTR图上划定感兴趣区域，覆盖所有潜在的残留肿瘤和纤维化区域。计算平均MTR和直方图参数（最小值、最大值、中位数、标准差、偏度、峰度以及第5、30、70、95百分位数）。参考标准为组织学TRG1 - 2（良好反应）和TRG3 - 5（不良反应）。
30例患者中24例为男性；平均年龄为67.7±10.8岁。平均MTR区分TRG1 - 2与TRG3 - 5的受试者工作特征曲线下面积（AUC）分别为0.65（阅片者1）和0.87（阅片者2）。第95百分位数获得的结果最佳（AUC为0.75 - 0.88）。平均MTR的观察者间一致性为中等（组内相关系数ICC 0.50），第95百分位数的观察者间一致性良好（ICC 0.80）。
MT成像在评估直肠癌放化疗后的肿瘤反应方面是一种有前景的工具。特别是，第95百分位数的AUC高达0.88，可用于鉴别良好的肿瘤反应。
• 平均MTR可区分放化疗后的良好和不良反应者。• 除测量平均值外，直方图分析可能有益。• 直方图参数第95百分位数的AUC可达0.75 - 0.88。
