探讨经直肠腔内超声弹性成像对局部进展期直肠癌新辅助放化疗后T分期的应用价值。

收集就诊于中国医学科学院肿瘤医院的局部进展期直肠癌患者57例，均于术前接受新辅助放化疗，并进行根治性手术。所有患者新辅助放化疗前后行经直肠腔内超声（ERUS）及剪切波弹性成像（SWE）检查。以术后病理为金标准，评价ERUS及SWE对直肠癌新辅助放化疗后T分期的准确性。

ERUS对局部进展期直肠癌新辅助放化疗后T分期的诊断准确率为59.6%（34/57）。ERUS判断肿瘤局限于肠壁（T0~T2）的准确性为39.3%（11/28）。46.2%（6/13）的ypT0期患者被过高分期。放化疗前后，杨氏模量最大值（Emax）平均值分别为（103.27±29.23）kPa、（49.91±32.67）kPa，差异有统计学意义（t=6.236，P<0.001）。新辅助治疗后病理T分期越高，Emax平均值随之升高。以放化疗后病灶Emax构建ROC曲线，选取58 kPa作为最佳诊断临界点时，诊断放化疗后残余病变局限于肠壁内的敏感性、特异性、准确性分别为76.2%、86.4%、78.9%；以43 kPa为最佳诊断临界点，诊断ypT0期的敏感性、特异性、准确性分别为100%、84.6%、89.7%，均较ERUS有改善，说明SWE可提高新辅助治疗后直肠癌再分期的准确性，有助于临床治疗方案的制定。

经直肠腔内SWE可提高局部进展期直肠癌新辅助放化疗后T分期的准确性，可丰富现有影像检查方法。

To investigate the value of endorectal shear wave elastography in T staging of locally advanced rectal cancer after neoadjuvant radiochemotherapy.

Fifty-seven patients with locally advanced rectal cancer who received neoadjuvant chemoradiotherapy and radical surgery were included. The postoperative pathologic results were used as gold standard to evaluate the diagnostic accuracy of endorectal shear wave elastography (SWE) and endorectal ultrasound (ERUS) in T staging of rectal cancer after neoadjuvant radiochemotherapy.

The diagnostic accuracy of ERUS in T staging of locally advanced rectal cancer after neoadjuvant chemoradiotherapy was 59.6% (34/57). The diagnostic accuracy of ERUS in distinguishing whether a tumor was confined to the intestinal wall (T0-T2) was 39.3% (11/28). 46.2% (6/13) of ypT0 patients were over staged. The mean maximum values of the Young's modulus (Emax) of the lesions before and after chemoradiotherapy were (103.27±29.23) kPa and (49.91±32.67) kPa, respectively. The difference was statistically significant (P<0.001). The Emax values increase with T stage after neoadjuvant chemoradiotherapy. Receiver operating characteristic curves were constructed from Emax values of the lesions after neoadjuvant chemoradiotherapy. After calculation, 58 kPa was determined to be the optimized threshold for diagnosing the residual lesions confined to the intestinal wall (ypT0-2) after chemoradiotherapy, and the sensitivity, specificity and accuracy were 76.2%, 86.4%, 78.9%, respectively. 43 kPa was determined to be the optimized threshold for diagnosing no residual tumor in intestinal wall (ypT0) after chemoradiotherapy, and the sensitivity, specificity and accuracy were 100%, 84.6%, 89.7%, respectively, indicating that shear wave elastography can improve the accuracy of rectal cancer restaging after neoadjuvant treatment, which is helpful for clinical decision making.

Endorectal SWE can improve the diagnostic efficacy of T staging in locally advanced rectal cancer after neoadjuvant chemoradiotherapy and enrich the existing imaging methods.