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Bowel wall thickening is a radiological finding seen on CT, MRI, or ultrasound, reflecting an increase in the normal wall thickness:
Small bowel: normally ≤3 mm (distended) and ≤5 mm (collapsed).
Colon: normally ≤5 mm (distended). </aside>
Thickening can be focal, segmental, or diffuse and may be due to neoplastic, inflammatory, infectious, ischemic, or other causes.
The Radiology Assistant : CT-pattern of Bowel wall thickening
Wall involvement patterns. PM colitis: pseudomembranous colitis; CMV Colitis: cytomegalovirus colitis; TB: tuberculosis; CD: Crohn's disease; GVHD: Graft-versus-host disease; SLE: systemic lupus erythematosus.
Martínez Pérez MJ, Blanc García E, Merino Bonilla JA. Bowel ultrasound: Examination techniques and normal and pathologic patterns. Radiología (English Edition). 2020;62(6):517-527. doi:https://doi.org/10.1016/j.rxeng.2020.09.003
Richard Gore and Robin Smithuis, Professor of Radiology, University of Chicago, Evanston, IL, USA and the Rijnland hospital in Leiderdorp, the Netherlands The Radiology Assistant : CT-pattern of Bowel wall thickening. Published May 21, 2014. https://radiologyassistant.nl/abdomen/bowel/bowel-wall-thickening-ct-pattern
Lenght of bowel wall involvement
Richard Gore and Robin Smithuis, Professor of Radiology, University of Chicago, Evanston, IL, USA and the Rijnland hospital in Leiderdorp, the Netherlands The Radiology Assistant : CT-pattern of Bowel wall thickening. Published May 21, 2014. https://radiologyassistant.nl/abdomen/bowel/bowel-wall-thickening-ct-pattern
Overview of enhancement pattern: The figure shows an overview of the CT-patterns of mural enhancement in patients with bowel wall thickening.
Richard Gore and Robin Smithuis, Professor of Radiology, University of Chicago, Evanston, IL, USA and the Rijnland hospital in Leiderdorp, the Netherlands The Radiology Assistant : CT-pattern of Bowel wall thickening. Published May 21, 2014. https://radiologyassistant.nl/abdomen/bowel/bowel-wall-thickening-ct-pattern
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| Etiology | Extent | Symmetry | Enhancement Pattern | Associated Features |
|---|---|---|---|---|
| Adenocarcinoma | Focal | Asymmetric | Solid, heterogeneous | Obstruction, apple-core lesion |
| Lymphoma | Segmental | Symmetric | Homogeneous | Aneurysmal dilatation, bulky nodes |
| Crohn’s | Segmental | Asymmetric | Stratified (target sign) | Skip lesions, fistulae, creeping fat |
| Ulcerative colitis | Diffuse | Symmetric | Stratified (chronic solid) | Lead pipe colon, continuous involvement |
| Ischemia | Segmental | Symmetric | Stratified (edema) or thin wall | Pneumatosis, vessel occlusion |
| Pseudomembranous | Diffuse | Symmetric | Accordion sign | Toxic megacolon risk |
| TB (ileocecal) | Segmental | Asymmetric | Irregular, heterogeneous | Necrotic nodes, pulled-up cecum |
| Radiation enteritis | Segmental | Symmetric | Hypoenhancing/fibrotic | Strictures, pelvic location |