Difference between revisions of "MRI of rectal cancer"
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Rhcastilhos (talk | contribs) (Created page with "{{Top |author1=Rodrigo Horstmann Castilhos |author2= }} == T staging == '''Clinical T staging''' *T1: Limited to submucosa *T2: Invading muscularis prop...") |
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| + | == Choice of modality == | ||
| + | |||
| + | '''MRI (first choice)''' | ||
| + | * Mandatory for both primary staging and restaging of rectal cancer. | ||
| + | |||
| + | '''Endorectal ultrasound (EUS)''' | ||
| + | * Staging for early tumours considered for local excision | ||
| + | * Superior diagnostic performance for differentiating T1 from T2 tumors. | ||
| + | |||
| + | == Patient preparation == | ||
| + | '''Spasmolytics (optional)''' | ||
| + | * Can be benefical for upper rectal tumors and when imaging is performed at 3.0T (bowel movement artifacts are most prevalent) | ||
| + | |||
| + | '''Endorectal filling (optional) (~60 ml of gel)''' | ||
| + | * When used, some experts suggest using a volume of only ~60 ml of gel, since higher volumes will compress perirectal tissues significantly | ||
| + | * Useful to reduce susceptibility artefacts related to luminal gas during diffusion-weighted MRI. | ||
| + | * Its use is not reccomended routinely: rectal wall distension may interfere with interpretation of the distance between the tumour and the mesorectal fascia, and high T2 signal of the gel may cause T2 shine through effects on DWI. | ||
== T staging == | == T staging == | ||
| Line 14: | Line 32: | ||
**T4b: Directly invades or is adherent to other organs/structures | **T4b: Directly invades or is adherent to other organs/structures | ||
| − | + | == MRI T staging == | |
* MRI doesn't differentiate T1 from T2 | * MRI doesn't differentiate T1 from T2 | ||
*'''T1-T2: limited to intestinal wall''' | *'''T1-T2: limited to intestinal wall''' | ||
| Line 23: | Line 41: | ||
** '''T3c or T3d: >5 mm extramural growth''' | ** '''T3c or T3d: >5 mm extramural growth''' | ||
* '''T4''' | * '''T4''' | ||
| + | |||
| + | === Information relevant to surgical approach === | ||
| + | For low tumours with sphincter invasion, describe: | ||
| + | |||
| + | Depth of invasion | ||
| + | * invades only the internal sphincter muscle | ||
| + | * also involves the intersphincteric plane | ||
| + | * also involves the external sphincter | ||
| + | |||
| + | Height of invasion | ||
| + | * involves only the proximal 1/3 of the complex/anal canal | ||
| + | * also involves the middle 1/3 of the complex/anal canal | ||
| + | * also involves the lower 1/3 of the complex/anal canal | ||
| + | * involves pelvic floor (levator) | ||
== N staging == | == N staging == | ||
Revision as of 19:36, 15 July 2019
Author:
Rodrigo Horstmann Castilhos [notes 1]
Contents
Choice of modality
MRI (first choice)
- Mandatory for both primary staging and restaging of rectal cancer.
Endorectal ultrasound (EUS)
- Staging for early tumours considered for local excision
- Superior diagnostic performance for differentiating T1 from T2 tumors.
Patient preparation
Spasmolytics (optional)
- Can be benefical for upper rectal tumors and when imaging is performed at 3.0T (bowel movement artifacts are most prevalent)
Endorectal filling (optional) (~60 ml of gel)
- When used, some experts suggest using a volume of only ~60 ml of gel, since higher volumes will compress perirectal tissues significantly
- Useful to reduce susceptibility artefacts related to luminal gas during diffusion-weighted MRI.
- Its use is not reccomended routinely: rectal wall distension may interfere with interpretation of the distance between the tumour and the mesorectal fascia, and high T2 signal of the gel may cause T2 shine through effects on DWI.
T staging
Clinical T staging
- T1: Limited to submucosa
- T2: Invading muscularis propria
- T3: Invading pericolorectal tissues (mesorectal fat)
- T4: Invading visceral peritoneum or other organs/structures
- T4a: Penetrates to the surface of visceral peritoneum
- T4b: Directly invades or is adherent to other organs/structures
MRI T staging
- MRI doesn't differentiate T1 from T2
- T1-T2: limited to intestinal wall
- Good prognosis
- Rectal wall has an intact black line (outer muscle) surrounding the tumor
- T3: extramural growth
- T3a or T3b: ≤5 mm extramural growth
- T3c or T3d: >5 mm extramural growth
- T4
Information relevant to surgical approach
For low tumours with sphincter invasion, describe:
Depth of invasion
- invades only the internal sphincter muscle
- also involves the intersphincteric plane
- also involves the external sphincter
Height of invasion
- involves only the proximal 1/3 of the complex/anal canal
- also involves the middle 1/3 of the complex/anal canal
- also involves the lower 1/3 of the complex/anal canal
- involves pelvic floor (levator)
N staging
- Important risk factor for local recurrence
Morphologically suspicious characteristics
- Round shape
- Irregular border
- Heterogeneous signal
Malignant node criteria
- Short axis diameter ≥9 mm
- Short axis diameter 5-8 mm + ≥ 2 morphologically suspicious characteristics
- Short axis diameter <5 mm + 3 morphologically suspicious characteristics
- Mucinous lymph node (of any size)
N restaging
MRI protocol
- High resolution
- Contrast medium is optional
- Coronal images parallel to anal canal
- Slice thickness ≤ 3 mm
Treatment
Notes
- ↑ For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Radlines:Authorship for details.
References
Beets-Tan RGH, Lambregts DMJ, Maas M, et al. Magnetic resonance imaging for clinical management of rectal cancer: Updated recommendations from the 2016 European Society of Gastrointestinal and Abdominal Radiology (ESGAR) consensus meeting [published correction appears in Eur Radiol. 2018 Jan 10;:]. Eur Radiol. 2018;28(4):1465–1475. doi:10.1007/s00330-017-5026-2
