MRI anatomy of the rectum: key concepts important for rectal cancer staging and treatment planning.
Nino BogveradzePetur SnaebjornssonBrechtje A GrotenhuisBaukelien van TriestMax J LahayeMonique MaasGeerard L BeetsRegina G H Beets-TanDoenja M J LambregtsPublished in: Insights into imaging (2023)
A good understanding of the MRI anatomy of the rectum and its surroundings is pivotal to ensure high-quality diagnostic evaluation and reporting of rectal cancer. With this pictorial review, we aim to provide an image-based overview of key anatomical concepts essential for treatment planning, response evaluation and post-operative assessment. These concepts include the cross-sectional anatomy of the rectal wall in relation to T-staging; differences in staging and treatment between anal and rectal cancer; landmarks used to define the upper and lower boundaries of the rectum; the anatomy of the pelvic floor and anal canal, the mesorectal fascia, peritoneum and peritoneal reflection; and guides to help discern different pelvic lymph node stations on MRI to properly stage regional and non-regional rectal lymph node metastases. Finally, this review will highlight key aspects of post-treatment anatomy, including the assessment of radiation-induced changes and the evaluation of the post-operative pelvis after different surgical resection and reconstruction techniques.
Keyphrases
- rectal cancer
- lymph node
- locally advanced
- radiation induced
- neoadjuvant chemotherapy
- contrast enhanced
- magnetic resonance imaging
- cross sectional
- sentinel lymph node
- radiation therapy
- diffusion weighted imaging
- computed tomography
- emergency department
- squamous cell carcinoma
- deep learning
- early stage
- magnetic resonance
- combination therapy
- adverse drug
- replacement therapy