Clinical Sciences Department, Faculty of Medicine, University of Las Palmas de Gran Canaria, Paseo Blas Cabrera Felipe, s/n. 35016, Las Palmas de Gran Canaria, Spain.
Department of General Surgery, Complejo Hospitalario Universitario Insular Materno-Infantil, Av. Marítima, s/n. 35016, Las Palmas de Gran Canaria, Spain.
Abdom Radiol (NY). 2019 Nov;44(11):3674-3682. doi: 10.1007/s00261-019-02139-4.
To analyze changes in MRI diagnostic accuracy in main rectal tumor (T) evaluation resulting from the use of diffusion-weighted imaging (DWI), according to the degree of experience of the radiologist.
This is a cross-sectional study of a database including one hundred 1.5 T MRI records (2011-2016) from patients with biopsy-proven rectal cancer, including primary staging and post-chemoradiotherapy follow-up. All cases were individually blindedly reviewed by ten radiologists: three experienced in rectal cancer, three specialized in other areas, and four residents. Each case was assessed twice to detect perirectal infiltration: first, evaluating just high-resolution T2-weighted sequences (HRT2w); second, evaluation of DWI plus HRT2w sequences. Results were pooled by experience, calculating accuracy (area under ROC curve), sensitivity and specificity, predictive values, likelihood ratios, and overstaging/understaging. Histology of surgical specimens provided the reference standard.
DWI significantly improved specificity by experienced radiologists in primary staging (63.2% to 75.9%) and, to a lesser extent, positive likelihood ratio (2.06 to 2.87); minimal changes were observed post-chemoradiotherapy, with a slight decrease of accuracy (0.657 to 0.626). Inexperienced radiologists showed a similar pattern, but with slight enhancement post-chemoradiotherapy (accuracy 0.604 to 0.621). Residents experienced small changes, with increased sensitivity/decreased specificity in both primary (69% to 72%/67.2% to 64.7%) and post-chemoradiotherapy (68.1% to 73.6%/47.3% to 44.6%) staging.
Adding DWI to HRT2w significantly improved specificity for the detection of perirectal infiltration at primary staging by experienced radiologists and also by inexperienced ones, although to a lesser extent. In the post-neoadjuvant treatment subgroup, only minimal changes were observed.
分析扩散加权成像（DWI）在直肠主肿瘤（T）评估中的应用对磁共振成像（MRI）诊断准确性的影响，根据放射科医生的经验程度进行分析。
这是一项回顾性数据库研究，纳入了 100 例经活检证实的直肠癌患者 1.5 T MRI 记录（2011-2016 年），包括原发分期和放化疗后随访。所有病例均由 10 名放射科医生进行个体盲法复查：3 名具有直肠癌诊治经验，3 名专业领域为其他，4 名为住院医师。每位医生对每个病例进行两次评估，以检测直肠周围浸润：第一次评估仅使用高分辨率 T2 加权序列（HRT2w）；第二次评估使用 DWI 加 HRT2w 序列。根据经验对结果进行汇总，计算准确性（ROC 曲线下面积）、敏感度、特异度、预测值、似然比和过分期/分期不足。手术标本的组织学检查为参考标准。
在原发分期中，DWI 显著提高了有经验放射科医生的特异性（63.2%至 75.9%），阳性似然比也略有升高（2.06 至 2.87）；放化疗后，其特异性有轻微改善，准确性略有下降（0.657 至 0.626）。无经验放射科医生也表现出类似模式，但放化疗后稍有改善（准确性 0.604 至 0.621）。住院医师的变化较小，原发期（69%至 72%/67.2%至 64.7%）和放化疗后（68.1%至 73.6%/47.3%至 44.6%）的敏感性增加，特异性降低。
在 HRT2w 基础上增加 DWI 可显著提高有经验和无经验放射科医生对原发期直肠周围浸润的检测特异性。在新辅助治疗后亚组中，仅观察到微小变化。
