MRI对T_3、T_4期直肠癌术前新辅助治疗疗效评估价值

The value of MRI in assessing the effect of neoadjuvant therapy for stage T3 and T4 rectal cancer before surgery

目的：探讨MRI对T3、T4期直肠癌术前新辅助治疗疗效的评价.方法：回顾性分析45例经病理证实的T3、T4期直肠癌患者术前新辅助治疗前后的MRI影像资料.分析肿瘤大小、肿瘤累及肠管周径的范围、累及肠管的长度范围、增强表现、侵犯层次、管周筋膜情况、管周淋巴结有无肿大、直肠周围器官累及情况、T分期.结果：术前新辅助治疗前后MRI检查对45例直肠肿瘤病变均显示良好,术前新辅助治疗前肿瘤3～≤5 cm 15例,＞5 cm 30例;累及肠管周径1/2以上未达全周径17例,全周径28例;累及肠管长度3.0～≤5.0 cm 14例,＞5.0 cm 31例;侵犯肌层19例,侵犯直肠系膜15例,侵犯系膜筋膜11例;45例肿瘤均表现为中等度强化,累及周围器官26例;45例DWI均表现为高信号,ADC值均降低;T3期19例,T4期26例.术前新辅助治疗后肿瘤大小＜1.0 cm 10例,1.0～＜3.0 cm 18例,3.0～＜5.0 cm 13例,≥5 cm 4例;累及肠管周径＜1/3 7例,1/3～＜1/2 19例,1/2～＜全部周径10例,全部周径9例;累及肠管长度＜1.0 cm 8例,1.0～＜3.0 cm 25例,3.0～＜5.0 cm 9例,≥5.0cm3例;侵犯黏膜层及黏膜下层15例,肌层25例,直肠系膜5例;45例肿瘤均表现为轻度强化,累及周围器官5例;45例DWI均表现为低信号,ADC值均升高.术前新辅助治疗后T分期变化：T1期5例,T2期28例,T3期7例,T4期5例.术后病理分期：T1期4例,T2期29例,T3期7例,T4a期2例,T4b期3例.结论：MRI可以对直肠癌T3、T4期患者术前新辅助治疗前后做出良好的分期,能够正确判断直肠癌术前新辅助治疗后的降期情况.

Objective：To evaluate MR examination in assessing the effect of neoadjuvant therapy for stage T3 and T4 rectal cancer before surgery.Methods：MRI data of the pre-and post-neoadjuvant therapy before surgery in 45 cases pathologically confirmed to be stage T3 and T4 rectal cancer were analyzed retrospectively.The following items were assessed：the size of tumor,the extent of tumor invasion including infiltration of the intestinal circumference,the length of tumor invasion,MRI characteristics after enhanced imaging,intestinal fascia invasion,lymph nodes enlargement,conditions of the adjacent structures and the staging of tumor.Results：Pre-neoadjuvant therapy：In 15 cases the tumor was 3～≤5 cm,＞5 cm in 30 cases.In 17 cases the tumor involved less than 1/2 of the whole circumference of the rectum,involved entire circumference in 28 cases.In 14 cases the length of tumor invasion was 3.0～≤5.0 cm,＞5.0 cm in 31 cases.Tumor infiltrated to muscular layer in 19 cases,infiltrated the rectal mesentery 15 cases,and the mesenteric fascia in 11 cases.Tumor in all the 45 cases showed medium enhancement,the adjacent organs involved in 26 cases.On DWI,tumor in the 45 cases all showed hyperintensity.The ADC value decreased.Nineteen cases belong to stage T3 and 26 cases were T4.After neoadjuvant therapy,the size of tumor：＜1.0 cm in 10 cases,1.0～＜3.0 cm in 18 cases,3.0～＜5.0 cm in 13 cases,≥5.0 cm in 4 cases.Involvement of rectum circumference ＜1/3 in 7 cases,1/3～＜1/2 in 19 cases,≥1/2 but without involvement of the entire circumference in 10 cases,involved the entire circumference in 9 cases.The length of involvement ＜1.0 in 8 cases,1.0～＜3.0 cm in 25 cases,3.0～＜5.0 cm in 9 cases,≥5.0 cm in 3 cases.Invasion to mucosal and submucosal layer in 15 cases,invasion of muscular layer in 25 cases,recal mesentery in 5 cases.The tumor in 45 cases all showed mild to medium enhancement.Involvement of the adjacent organs in 5 cases.On DWI all the tumors were hypointense.ADC value increased.The change of staging：T1 in 5 cases,T2 in 28 cases,T3 in 7 cases,and T4 in 5 cases.Pathological staging after operation：T1 in 4 cases,T2 in 29 cases,T3 in 7 cases,T4a in 2 cases,and T4b in 3 cases.Conclusion：MRI is important and valuable in staging of T3 and T4 rectal cancer pre-and post-neoadjuvant therapy before surgerical operation,and in assessing the effect of the neoadjuvant therapy.