title: Magnetic resonance imaging in rectal cancer: a surgeon's perspective.
abstract: Magnetic resonance imaging (MRI) in rectal cancer was first investigated in 1999 and has become almost mandatory in planning rectal cancer treatment. MRI has a high accuracy in predicting circumferential resection margin involvement and is used to plan neoadjuvant therapy. The accuracy of MRI in assessing mesorectal lymph nodes remains moderate, as there are no reliable criteria to assess nodal involvement. MRI seems to be good in assessing peritoneal involvement in upper rectal cancer; this however has been assessed in only a few studies and needs further research. For low rectal cancers, mesorectum is thin at the level of levator ani especially in relation to prostate; so predicting circumferential resection margin involvement is not easy. However high spatial resolution coronal imaging shows levator muscles, sphincter complex and intersphincteric plane accurately. This is used to stage low rectal tumors and plan plane of surgery (standard surgery, intersphincteric resection, Extralevator abdominoperineal resection). While most centres perform MRI post chemoradiotherapy, its role in accurate staging post neoadjuvant therapy remains debatable. THe role of Diffusion weighted MRI post neoadjuvant therapy is being evaluated in research settings.
authors.affiliation: Avanish P Saklani, Sung Uk Bae, Nam Kyu Kim, Section of Colon and Rectal Surgery, Department of Surgery, Yonsei University College of Medicine, Seoul 120527, South Korea.
authors.forename: Avanish P
authors.initials: AP
authors.lastname: Saklani
authors.affiliation: Avanish P Saklani, Sung Uk Bae, Nam Kyu Kim, Section of Colon and Rectal Surgery, Department of Surgery, Yonsei University College of Medicine, Seoul 120527, South Korea.
authors.forename: Sung Uk
authors.initials: SU
authors.lastname: Bae
authors.affiliation: Avanish P Saklani, Sung Uk Bae, Nam Kyu Kim, Section of Colon and Rectal Surgery, Department of Surgery, Yonsei University College of Medicine, Seoul 120527, South Korea.
authors.forename: Amy
authors.initials: A
authors.lastname: Clayton
authors.affiliation: Avanish P Saklani, Sung Uk Bae, Nam Kyu Kim, Section of Colon and Rectal Surgery, Department of Surgery, Yonsei University College of Medicine, Seoul 120527, South Korea.
authors.forename: Nam Kyu
authors.initials: NK
authors.lastname: Kim
mesh_terms: D059248:Chemoradiotherapy; D038524:Diffusion Magnetic Resonance Imaging; D005290:Ferric Compounds / Q000737:chemistry; D006801:Humans; D008279:Magnetic Resonance Imaging; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000473:pathology* / Q000601:surgery*; D015203:Reproducibility of Results; D016896:Treatment Outcome
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide
keywords: Magnetic resonance imaging; Rectal cancer; Surgeon