直肠癌：MRI与临床(1).pptx

杨景震 编译制作,直肠癌：MRI与临床,（内有动画设计，浏览请用放映模式）,直肠为大肠的末段，长约15-16cm，位于小骨盆内。上端平第3骶椎处接续乙状结肠，沿骶骨和尾骨的前面下行，穿过盆膈，下端以肛门而终。,直肠,肛门,外科学上，将由盆筋膜脏层包绕的直肠周围脂肪结缔组织、血管、神经和淋巴组织统称之为直肠系膜（mesorectum）。直肠癌环周切缘（circum ferential resection Margin，CRM）是一个外科学概念，是指围绕直肠系膜的盆腔脏层筋膜，即直肠系膜筋膜（mesoretal fascia，MRF）。,相关基本概念,全直肠系膜切除术（total mesorectal excision TME）解剖学基础：腹膜返折以上的直肠有腹膜覆盖，返折以下的直肠无腹膜，而由盆筋膜所覆盖。盆筋膜分脏层和壁层，其脏层是由腹膜下筋膜向下位于腹膜返折以下，其浅叶包绕盆腔的内脏，如膀胱、子宫、直肠等而形成。盆筋膜壁层与脏层相对应，是由腹膜下筋膜的深叶进入盆腔后覆盖盆壁四周而形成的。,临床意义：直肠系膜筋膜（MRF）是直肠与周围邻近器官间的重要屏障，可有效防止直肠炎症或肿瘤等向其它腹膜外间隙扩散，对阻止肿瘤局部浸润和远处转移有重要意义。,来源：中国临床解剖学杂志2005年第23卷第4期,明确直肠系膜的解剖学结构是应用全直肠系膜切除术(total mesorectal excision,TME)治疗直肠癌的基础。但至今，有关直肠系膜的报道也仅限于零星的外科解剖资料1,2，对直肠系膜形态结构的解剖学研究存在较大的分歧3。该文章进行了专题解剖学研究，以期为临床TME广泛开展提供应用基础理论。,研究显示：1 直肠系膜筋膜（即盆脏筋膜）在直肠和直肠系膜周围是一个连续、完 整的结构，下端止于直肠肛管连接处；2 直肠系膜是由环绕在直肠周围的血管、淋巴管、神经及脂肪等疏松 的结缔组织构成。本结果与Bisset等4的研究相类似。直肠系膜的定义应该是包绕在袖套样直肠系膜筋膜（即盆脏筋膜，并包括该筋膜在内）之内的直肠周围所有的血管、淋巴管和淋巴结、神经及脂肪组织等。,作者通过仔细地解剖盆脏筋膜，认为直肠和“直肠系膜”一起被完整地包裹在含胶原纤维的袖套样盆脏筋膜中，因此，沿直肠盆脏筋膜外解剖，可以将直肠系膜完整地切除，并且切除后腹下神经和盆丛仍完整地保留在盆腔侧壁上，未受损害。本研究用MRI检测直肠系膜的结果也证实了这一点。,解剖学研究与MRI影像,图2 盆腔标本解剖前的 MRI(T1WI)箭头示直肠系膜筋膜为均匀的低信号线；三角示直肠系膜则为均匀高信号。,图3 盆腔标本解剖后的 MRI(T1WI)箭头示直肠系膜筋膜所产生的低信号线所在的位置；三角示直肠系膜。,图1 盆腔矢状剖面新鲜标本（虚线之间为直肠系膜）。,来源：中国临床解剖学杂志2005年第23卷第4期,Denonvillers Fascia（DVF，邓氏筋膜）,向两侧方与直肠系膜相延续,向上与腹膜返折处的腹膜相延续,向下经盆膈连于会阴中心腱,前方附于前列腺、精囊与阴道后壁,后方以一层薄的疏松结缔组织与直肠固有筋膜相连,其实，该区域还有另一个解剖结构，但MRI却不能分辨了！,Rectal Cancer-MR staging 2.0Rhiannon van Loenhout,Frank Zijta,Max Lahaye,Regina Beets-Tan and Robin Smithuis Radiology Departement of the Medical Centre Haaglanden in the Hague,The Netherlands Cancer Institute in Amsterdam and the Alrijne Hospital in Leiderdorp,the Netherlands,直肠癌：MR分期,Introduction Total mesorectal excision TNM-stage MR protocol DWI Location of the tumor Low rectal cancer T-stage T1 and T2 T3 T3 with MRF involvement T4a-Invasion peritoneal reflection T4b-Invasion surrounding organs Extramural vascular invasion(EMVI)N-stage Extramesorectal lymph nodes Regional Lymph nodes,Surgery Low Anterior Resection(LAR)Abdomino-Perineal-Resection(APR)Intersphincteric APR and ELAPE Chemo-and Radiotherapy Structured MR report,Publication date December 17,2015 This is an updated version of the 2010 article.The two major advancements in the treatment of rectal cancer are total mesorectal excision(TME),and neoadjuvant radiotherapy and chemotherapy(1,2,3).Both have dramatically changed the local recurrence and survival rates.MRI is the most accurate tool for the local staging of rectal cancer and is a powerful tool to select the appropriate treatment(4,5,6).The decision whether a patient with rectal cancer is a candidate for TME only or neoadjuvant therapy followed by TME,is made on the findings on MRI(7).,2015年12月17日的更新版：直肠癌治疗的2个重要进展，一是全直肠系膜切除术(TME)，二是新辅助放疗和化疗。这两方面的措施明显改善了直肠癌局部的复发率和生存率。MRI是直肠癌局部分期最精确的评价方法，并作为非常有用的工具用于选择适宜的治疗。这里讨论的问题是：直肠癌病人，是只能选择TME？还是采用新辅助治疗而随后再行TME？通过MRI的表现作出决定。,The mesorectal fascia(MRF)plays a crucial role in the treatment plannnig.In TME the mesorectal fascia is the resection plane and it has to be tumor-free.A distance of the tumor to the mesorectal fascia of 1 mm is regarded as not suitable for TME and is called an involved MRF.This means that the tumor has to be downstaged before TME is possible.On MRI the mesorectal fat has high signal intensity on both T1-and T2-weighted images.The mesorectal fat is surrounded by the mesorectal fascia,which is seen as a fine line of low signal intensity(arrows).High resolution T2-images are needed to clearly identify the MRF(7).,Rectum is surrounded by mesorectal fat within the mesorectal fascia(arrows).,Total mesorectal excisionIn 1979 surgeon Richard John Heald introduced the total mesorectal excision(TME).In TME the entire mesorectal compartment including the rectum,surrounding mesorectal fat,perirectal lymph nodes and its envelope,the mesorectal fascia(MRF),is completely removed by precise dissection along anatomical planes(figure).TME is the best surgical treatment for rectal cancer provided that the resection margin is free of tumor.It is now a standard technique and part of procedures such as low anterior resection(LAR),in which the rectum and sigmoid colon are resected or abdominoperineal resections(APR),in which the rectum and anal canal are resected.,1979年外科医生Richard John Heald开展了全直肠系膜切除术（total mesorectal excision，TME）.TME中的全直肠系膜包括直肠、周围系膜脂肪、淋巴结及其包膜，即直肠系膜筋膜（mesoretal fascia，MRF）完全切除（图）。全直肠系膜切除术(TME)已被证明是直肠癌根治的最佳外科手术方法。,直肠由直肠系膜筋膜（箭）内直肠系膜的脂肪包绕,直肠系膜筋膜,全直肠系膜切除,*MRF在直肠癌治疗计划中扮演关键角色。*在TME中，做直肠系膜筋膜切除计划必须要求该系膜筋膜无肿瘤侵犯。*癌灶至直肠系膜筋膜的距离1 mm 时，被认为不适合TME，这称为直 肠系膜筋膜受侵。*这意味着直肠癌在做TME之前必须处于早期。*在MRI上，直肠系膜脂肪在T1WI和T2WI表现为高信号。*直肠系膜脂肪由直肠系膜筋膜（盆腔脏层筋膜）环绕，表现为线样低信 号影（箭）。*为清晰地证实MRF结构，高分辨T2WI是必须的。,The MRF is only circumferential in the low-rectum below the anterior peritoneal reflection(see next illustration).The MRF does not apply to the anterior peritonealized surface of the anterior mid-and high rectum.,直肠系膜筋膜（MRF）仅仅是在前腹膜返折处下面的直肠下段呈圆周环绕；而直肠系膜筋膜（MRF）不适用于前表面由腹膜被覆的中、上段直肠。,直肠系膜（mesorectum）,The treatment of a patient with rectal cancer depends on the TNM-stage and whethe