Vliegen Roy F A, Beets Geerard L, Lammering Guido, Dresen Raphaëla C, Rutten Harm J, Kessels Alfons G, Oei Toen-Khiam, de Bruïne Adriaan P, van Engelshoven Jos M A, Beets-Tan Regina G H
Department of Radiology, University Hospital Maastricht, P. Debyelaan 25, 6202 AZ, Maastricht, the Netherlands.
Radiology. 2008 Feb;246(2):454-62. doi: 10.1148/radiol.2462070042.
To retrospectively assess sensitivity and specificity of magnetic resonance (MR) imaging after chemotherapy and radiation therapy for predicting tumor invasion of the mesorectal fascia (MRF) in locally advanced primary rectal cancer, by using results of histologic examination and surgery as the reference standard, and to determine morphologic MR imaging criteria for MRF invasion.
The Ethical Committee of University Hospital Maastricht approved this study and waived informed consent. Two observers independently scored postchemoradiation MR images in 64 patients with rectal cancer (38 male [mean age, 60 years] and 26 female [mean age, 64 years] patients) for MRF tumor invasion with a confidence level scoring system defined by subjective criteria. In a subsequent consensus reading session, morphologic MR criteria for invasion were defined by comparing morphologic changes with histologic findings. These criteria were evaluated and compared with the subjective criteria by comparing areas under the receiver operating characteristic curves (AUCs).
AUCs of postchemoradiation MR imaging for predicting MRF tumor invasion were 0.81 and 0.82 for observers 1 and 2, respectively. The following four types of morphologic tissue patterns at MR imaging were associated with whether or not MRF invasion was present at histologic examination: (a) development of fat pad larger than 2 mm (seen in no quadrants with and in four quadrants without invasion), (b) development or persistence of spiculations (seen in no quadrants with and in 22 quadrants without invasion), (c) development of diffuse hypointense "fibrotic" tissue (seen in 21 quadrants with and in 32 quadrants without invasion), and (d) persistence of diffuse iso- or hyperintense tissue (seen in 19 quadrants with and in two quadrants without invasion). AUC of postchemoradiation MR imaging for predicting MRF invasion on the basis of morphologic criteria was 0.80. There was no significant difference between the performance of subjective and morphologic criteria (P = .73-.76).
Postchemoradiation MR imaging findings have moderate accuracy for predicting tumor invasion of the MRF related to the limitation in differentiating between diffuse "fibrotic" tissue with and that without small tumor foci. Specific other types of morphologic patterns at MR imaging can highly predict a tumor-free or invaded MRF.
以组织学检查和手术结果作为参考标准，回顾性评估化疗和放疗后磁共振（MR）成像预测局部晚期原发性直肠癌中直肠系膜筋膜（MRF）受肿瘤侵犯的敏感性和特异性，并确定MRF侵犯的形态学MR成像标准。
马斯特里赫特大学医院伦理委员会批准了本研究并免除了知情同意。两名观察者使用主观标准定义的置信度评分系统，对64例直肠癌患者（38例男性[平均年龄60岁]和26例女性[平均年龄64岁]）的放化疗后MR图像进行MRF肿瘤侵犯评分。在随后的共识读片会议中，通过将形态学变化与组织学结果进行比较，确定了侵犯的形态学MR标准。通过比较受试者操作特征曲线（AUC）下的面积，对这些标准进行评估并与主观标准进行比较。
观察者1和观察者2的放化疗后MR成像预测MRF肿瘤侵犯的AUC分别为0.81和0.82。MR成像时以下四种形态学组织模式与组织学检查中是否存在MRF侵犯相关：（a）脂肪垫增大超过2 mm（在有侵犯的象限中未出现，在无侵犯的象限中有四个象限出现），（b）毛刺的出现或持续存在（在有侵犯的象限中未出现，在无侵犯的象限中有22个象限出现），（c）弥漫性低信号“纤维化”组织的出现（在有侵犯的象限中有21个象限出现，在无侵犯的象限中有32个象限出现），以及（d）弥漫性等信号或高信号组织的持续存在（在有侵犯的象限中有19个象限出现，在无侵犯的象限中有两个象限出现）。基于形态学标准的放化疗后MR成像预测MRF侵犯的AUC为0.80。主观标准和形态学标准的性能之间无显著差异（P = 0.73 - 0.76）。
放化疗后MR成像结果在预测与区分有和没有小肿瘤灶的弥漫性“纤维化”组织相关的MRF肿瘤侵犯方面具有中等准确性。MR成像中特定的其他形态学模式可以高度预测无肿瘤或受侵犯的MRF。
