Bowel wall thickening

Bowel wall thickening is a useful finding on imaging studies and has a number of different causes.

The reason for bowel wall thickening depends on the underlying etiology but includes submucosal edema, hemorrhage, and neoplastic infiltration.

In describing bowel wall thickening, certain descriptors should be considered when deriving a differential diagnosis 1

  • bowel wall thickness
    • mild, moderate, severe (subjective assessment)
  • bowel wall attenuation / enhancement pattern
  • length of affected segment(s)
    • short segment or multiple loops
    • small bowel and/or colon
    • continuous involvement or discontinuous
      • skip lesions
  • symmetrical or asymmetrical pattern
  • bowel wall thickening can be seen through thickening of the valvulae conniventes (small bowel) or haustral folds (colon)
  • the true thickness of the bowel wall should not be visible
    • if both sides of the bowel wall are visible, it likely indicates pneumoperitoneum
  • detection of bowel wall thickening on fluoroscopy is similar in principle to radiography and relies on evaluating the thickness of bowel wall folds
  • some sources suggest >2-3 mm as a numerical cut off for small bowel wall thickening 2
  • CT enterography is more useful for evaluation of bowel thickening because of
    • better luminal distention
    • earlier contrast timing that accentuates bowel wall mucosal enhancement
  • findings in MRI and MR enterography are mostly analogous to CT, but submucosal edema can be more directly evaluated with T2-weighted imaging
  • collapsed bowel

If due to an inflammatory condition, the thickening represents submucosal edema. This type of thickening can be seen in 

Bowel wall thickening may also be due to neoplastic infiltration of the wall, such as with

Bowel wall may be thickened in other conditions as well

  • differentiation between collapsed bowel and pathologic bowel wall thickening may be difficult -- look for secondary signs such as mesenteric edema, vascular engorgement, lymphadenopathy, or differential bowel wall enhancement to help confirm that the bowel wall thickening is abnormal
  • if trying to decide if bowel wall is thickened or just collapsed, compare the wall with other loops of bowel in nearby and distant segments
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Article information

rID: 56770
Section: Gamuts
Synonyms or Alternate Spellings:
  • Submucosal edema
  • Bowel wall edema
  • Submucosal oedema
  • Bowel wall oedema

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Cases and figures

  • Pancolitis
    Case 1: pseudomembranous colitis
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  • Case 2: Crohn disease
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  • Case 3: small bowel and mesenteric lymphoma
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