Learning objectives
To describe the rectum and anal canal anatomy.
To review the magnetic resonance imaging (MRI) techniques in the evaluation of the rectum and anal canal.
To review the main imaging findings and complications of most common benign anorectal diseases.
Background
Anorectal symptoms are caused by a variety of generally benign disorders that impact with the quality of life of many patients.
MRI has become an important imaging modality in the diagnosis of patients with anorectal diseases,
demonstrating in detail the complex anatomy of the pelvic floor,
rectum and anal canal.
MRI is also able to demonstrates numerous diseases and their complications.
In order to understand the anorectal pathologies,
first it is important to review the anorectal anatomy and MRI protocol [1,2].
Findings and procedure details
Anorectal anatomy
Therectumis a continuation of thesigmoid colonafter the rectosigmoid junction and continues as theanal canal at the anorectal angle created bypuborectalis muscle.
At the level of the S3 vertebral body,
the sigmoid colon loses itsmesenteryand becomes the rectum which is approximately 15 cm long.
The rectum extends from the rectosigmoid junction to proximal anorectal sphincter.
It does not have the distinctivehaustranorepiploic appendagesthat the rest of the large intestine has.
The lower part of the rectum is dilated and is called the rectal ampulla and...
Conclusion
The adequate characterization of benign anorectal diseases through MRI is crucial in the management of the patients.
The radiologist should be aware of the main imaging characteristics to assist the most appropriate approach.
Although most of the anorectal conditions are benign,
medical intervention is often required in order to improve the patients' quality of life.
The detection and correct characterization of anorectal diseases through MRI is one of the main tools in choosing the best treatment for the patients contributing to the selection of those...
Personal information
Isabela Alves
Department of Radiology,
Hospital Sírio-Libanês,
São Paulo/Brazil.
e-mail:
[email protected]
References
1.
Minematsu K.
Current status of the diagnosis and management of transient ischemic attack in Japan.
Rinsho Shinkeigaku [Internet].
2010;50(11):907–8.
Available from: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3002780&tool=pmcentrez&rendertype=abstract
2.
Gerard JP,
Benezery K.
Rectal cancer.
Target Vol Defin Radiat Oncol.
2015;(May):169–91.
3.
Coutinho A,
Bittencourt LK,
Pires CE,
Junqueira F,
de Oliveira Lima CMA,
Coutinho E,
et al.
MR Imaging in Deep Pelvic Endometriosis: A Pictorial Essay.
RadioGraphics [Internet].
2011 Mar;31(2):549–67.
Available from: http://pubs.rsna.org/doi/10.1148/rg.312105144
4.
Milligan ETC,
Morgan CN.
Surgical Anatomy of the Anal Canal.
Lancet [Internet].
1934;224(5804):1150–6.
Available from:...