背景 扩散加权成像(DW)在新辅助治疗后局部晚期直肠癌(LARC)的原发肿瘤床中检测肿瘤是有用的，但其在检测肿瘤外静脉侵犯(EMVI)和肿瘤沉积物方面的价值尚未得到很好的验证。目的 评估在新辅助治疗后LARC患者中使用整块病理标本对DW图像上活动的EMVI和肿瘤沉积物的诊断准确性和与患者预后的关联。材料和方法 回顾性研究纳入了2018年至2021年接受新辅助治疗和手术的患者。两名放射医师使用创新的五分Likert量表，独立地对四个轴向象限(12点至3点、3点至6点、6点至9点和9点至12点)的复发期DW MRI扫描中活动的EMVI和肿瘤沉积物的可能性进行评估。使用整块病理学作为参考标准，评估了每个象限和每个患者的诊断准确性。使用加权κ值进行读者间一致性分析，使用Cox回归模型进行无疾病生存和总生存分析。结果 共纳入了117例患者(平均年龄56岁±12[标准差]；男性70例，女性47例)。病理学证实有活动的EMVI和肿瘤沉积物的患者中有29例(25%)，在468个象限中有44个(9.4%)。每个象限的分析显示接受者工作特征曲线下面积为0.75(95%置信区间: 0.68, 0.83)，其敏感性和特异性分别为55%和96%。放射医师之间观察到良好的读者间一致性(κ = 0.62)。每个患者的分析显示敏感性和特异性分别为62%和93%。复发期DW MRI扫描中的EMVI和肿瘤沉积物的存在与较差的无疾病生存(hazard ratio [HR]，5.6；95%置信区间: 2.4, 13.3)和总生存(HR，8.9；95%置信区间: 1.6, 48.5)有关。结论 使用五分Likert量表的DW成像在新辅助治疗后LARC中检测活动的肿瘤外静脉侵犯和肿瘤沉积物方面具有较高的特异性和中等的敏感性，且其在复发期DW MRI扫描中的存在与较差的预后相关。在CC BY 4.0许可下发表。本文有补充资料可供参考。此外，本期编辑Méndez和Ayuso的社论也可参考。

Background Diffusion-weighted (DW) imaging is useful in detecting tumor in the primary tumor bed in locally advanced rectal cancer (LARC) after neoadjuvant therapy, but its value in detecting extramural venous invasion (EMVI) and tumor deposit is not well validated. Purpose To evaluate diagnostic accuracy and association with patient prognosis of viable EMVI and tumor deposit on DW images in patients with LARC after neoadjuvant therapy using whole-mount pathology specimens. Materials and Methods This retrospective study included patients who underwent neoadjuvant therapy and surgery from 2018 to 2021. Innovative five-point Likert scale was used by two radiologists to independently evaluate the likelihood of viable EMVI and tumor deposit on restaging DW MRI scans in four axial quadrants (12 to 3 o'clock, 3 to 6 o'clock, 6 to 9 o'clock, and 9 to 12 o'clock). Diagnostic accuracy was assessed at both the per-quadrant and per-patient level, with whole-mount pathology as the reference standard. Weighted κ values for interreader agreement and Cox regression models for disease-free survival and overall survival analyses were used. Results A total of 117 patients (mean age, 56 years ± 12 [SD]; 70 male, 47 female) were included. Pathologically proven viable EMVI and tumor deposit was detected in 29 of 117 patients (25%) and in 44 of 468 quadrants (9.4%). Per-quadrant analyses showed an area under the receiver operating characteristics curve of 0.75 (95% CI: 0.68, 0.83), with sensitivity and specificity of 55% and 96%, respectively. Good interreader agreement was observed between the radiologists (κ = 0.62). Per-patient analysis showed sensitivity and specificity of 62% and 93%, respectively. The presence of EMVI and tumor deposit on restaging DW MRI scans was associated with worse disease-free survival (hazard ratio [HR], 5.6; 95% CI: 2.4, 13.3) and overall survival (HR, 8.9; 95% CI: 1.6, 48.5). Conclusion DW imaging using the five-point Likert scale showed high specificity and moderate sensitivity in the detection of viable extramural venous invasion and tumor deposits in LARC after neoadjuvant therapy, and its presence on restaging DW MRI scans is associated with worse prognosis. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Méndez and Ayuso in this issue.