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World J Gastroenterol. Feb 28, 2014; 20(8): 2030-2041
Published online Feb 28, 2014. doi: 10.3748/wjg.v20.i8.2030
Magnetic resonance imaging in rectal cancer: A surgeon’s perspective
Avanish P Saklani, Sung Uk Bae, Amy Clayton, Nam Kyu Kim
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
Nam Kyu Kim, Department of Colorectal Surgery, Severance Hospital, Seoul 120527, South Korea
Amy Clayton, Radiology Department, University Hospital of Wales, CF14 4XW Cardiff, United Kingdom
Author contributions: Saklani AP, Bae SU and Clayton A researched the article; all the above and Kim NK planned and revised the manuscript.
Correspondence to: Nam Kyu Kim, MD, PHD, FACS, Professor, Department of Colorectal Surgery, Severance Hospital, 237 Ludlow building, Seoul 120527, South Korea. namkyuk@yuhs.ac
Telephone: +82-2-1058136963 Fax: +82-2-3138289
Received: September 28, 2013
Revised: November 27, 2013
Accepted: January 14, 2014
Published online: February 28, 2014
Processing time: 150 Days and 13.3 Hours
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.

Keywords: Magnetic resonance imaging; Rectal cancer; Surgeon

Core tip: Magnetic resonance imaging in rectal cancer is mandatory for a surgeon to plan neoadjuvant therapy. It also helps in planning surgical approach especially in low rectal cancer.