Rectal cancer protocol (MRI)

MRI protocol for rectal cancer is a group of MRI sequences put together for imaging staging of primary tumors of the rectum and assessment of response following neoadjuvant therapy. Modified versions of the protocol may also be used for the assessment of local recurrence.

Note: This article is intended to outline some general principles of protocol design. The specifics will vary depending on MRI hardware and software, radiologist's and referrer's preference, institutional protocols, patient factors (e.g. allergy) and time constraints. 

Bowel preparation

Bowel preparation is usually not necessary for rectal MRI.

Studies are usually performed without rectal distension 1. Rectal distension can be considered for assessment of smaller or polypoid lesions, or in post-operative recurrence, and can be done by infusion of warm water or warm ultrasound gel into the rectum before the scan.

Antispasmodic agents (eg. Buscopan (hyoscine) or glucagon) are commonly prescribed for reducing bowel peristalsis and consequent motion artifacts 1.

Sequences

A good protocol for this purpose involves at least:

  • overviews
    • sagittal T2
    • axial T2
  • small FOV T2 through tumor 
    • axial - perpendicular to the plane of the part of the rectum containing the tumor
    • coronal - parallel to the plane of the part of the rectum containing the tumor
  • optional
    • diffusion-weighted imaging
MRI protocols

Article information

rID: 9441
Synonyms or Alternate Spellings:
  • Pelvic MRI protocol for assessment of rectal cancer
  • Pelvic MRI protocol : Rectal cancer

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Cases and figures

  • Figure 1: standard coronal T2 sequence
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  • Figure 2: small field of view (FOV) axial T2 sequence
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  • Figure 3: sagittal T1 C+ fat sat sequence
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