高场强MRI与超声内镜对可切除性食管癌术前T分期应用价值的比较

The value of 3 T MR in preoperative T staging of potentially resectable esophageal cancer compared with endoscopic ultrasonography

目的 比较高场强MRI与超声内镜（EUS）对可切除性食管癌患者术前T分期的应用价值。方法 前瞻性收集2015年3月至2016年9月经临床及病理活检判定为可切除性食管癌的患者，所有入组患者于病理活检1周后进行MRI，扫描序列包括膈肌导航的应用刀锋采集技术的快速自旋回波的T2WI加权成像（BLADE-TSE-T2WI）、DWI及自由呼吸放射状K空间填充方式的容积内插体部检查（radial-VIBE）,同时行超声内镜（EUS）检查。MRI检查均在EUS之前进行，手术均在MRI与EUS检查后1周内进行。由2名具有5年以上MRI诊断经验的医师分别采用5分制对MR图像进行评分，参照美国癌症联合委员会（AJCC）第7版食管癌TNM分期标准。2名MRI阅片者采用双盲法分别对MR图像进行独立分期，结果不一致时，由第3名高级职称MRI医师共同讨论，达成一致意见，由1名具有5年以上内镜工作经验的内镜医师进行EUS分期。采用Kappa一致性检验，评价2名MRI阅片者对图像质量评分和可切除性食管癌术前T分期的一致性，以术后病理T分期结果为金标准，分别计算MRI及EUS对食管癌术前T分期的准确率，并采用χ2检验进行对照分析。结果 入组患者共70例，MRI图像质量评分不低于3分者分别有66例（阅片者1）和68例（阅片者2），2名MRI阅片者对图像质量评分的一致性非常好（Kappa=0.824，P〈0.05）。术后病理证实T1期16例、T2期18例、T3期30例、T4a期6例。2名MRI阅片者对食管癌术前T分期的一致性非常好（Kappa=0.809，P〈0.05），MRI和EUS对可切除性食管癌术前T分期的准确率分别为92.9%（65/70）和67.1%（47/70），两种技术的准确率差异有统计学意义（χ2=14.5，P〈0.05）。结论MRI对食管癌术前T分期的准确率明显高于EUS，可以成为判断食管癌术前T分期的无创性检查方法。

Objective To evaluate the value of 3T magnetic resonance imaging （MRI） in the preoperative T staging of potentially resectable esophageal cancer（EC）, compared with endoscopic ultrasonography （EUS）.Methods Patients with resectable EC pathologically confirmed by biopsy from March 2015 to September 2016 were prospectively enrolled. All patients underwent MRI （including T2-TSE-BLADE, DWI and radial-VIBE） and EUS one week after the biopsy, and MRI were performed prior to EUS, both MRI and EUS were acquired within one week before surgery. Two readers with more than 5 years experiences in the MRI diagnosis evaluated the MR image quality using a 5-point score independently. T staging was assigned on MRI and EUS by the two MRI readers using double-blind method and one endoscopist in accordance with the 7th edition of AJCC TNM Classification for EC, and any disagreement between two MRI readers was resolved by consensus with discussion to the third senior MRI doctor. The inter-observer agreement between two MRI readers were calculated using Kappa test for image quality scores and T staging results. Considering postoperative pathological T staging results as the gold standard, the performances of MRI and EUS were evaluated based on the accuracy rate and analyzed by χ2 test.Results A total of 70 patients were enrolled in the study, the good image quality cases （≥ 3 scores） were 66 in reader 1 and 68 in reader 2. The inter-observer agreement of the image quality scores by two readers was excellent （Kappa=0.824, P〈0.05）. The pathological results revealed 16 cases of T1 stage, 18 cases of T2 stage, 30 cases of T3 stage, and 6 cases of T4a stage. The inter-observer agreement of the preoperative T staging of EC by two readers was excellent （Kappa=0.809, P〈0.05）. The accuracy rates of MRI and EUS for preoperative T staging of EC were 92.9% （65/70） and 67.1% （47/70）, respectively, and the difference in accuracy rates of two techniques was statistically significant （χ2=14.5, P〈0.05）.Conclusions The accuracy rate of MRI for preoperative T staging of EC is significantly higher than that of EUS. MRI can be used as a noninvasive method for preoperative T staging of EC.