Abnormal bowel wall attenuation patterns

Changed by Daniel J Bell, 16 Oct 2017

Updates to Synonym Attributes

Updates to Article Attributes

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Abnormal bowel wall attenuation patterns on CT scan can be grouped under five categories:

  1. white enhancement
  2. gray enhancement
  3. water halo sign
  4. fat halo sign
  5. black attenuation

The first three patterns are seen on contrast studies.

White enhancement

It is defined as uniform enhancement of thickened bowel wall which is greater than or equal to the venous opacification.

Common differentials include:

  • idiopathic inflammatory bowel disease
  • vascular disorder
Gray enhancement

It is defined as homogeneous enhancement of thickened bowel wall that equals to the muscle enhancement. It is useful in differentiating benign withfrom malignant diseases.

Water halo sign

It corresponds to oedema in the submucosa (cf fat halo sign where there is fat infiltrating the submucosa). It may be seen in three forms:

  • outer hyperattenuating layer with inner oedematous layer
  • inner hyperattenuating layer with outer oedematous layer
  • oedematous submucosa between two hyperattenuating layers (target sign)

Common differentials include:

  • idiopathic inflammatory bowel disease
  • vascular disorder
  • infectious diseases
  • radiation damage
Fat halo sign

It represents infiltration of the submucosa with fat, between the muscularis and the mucosa.

It is considered pathognomonic for inflammatory bowel disease.

Black attenuation

It is synonymous with pneumatosis and the causes include:

  • trauma
  • ischaemia
  • infection
  • -</ul><h5>Gray enhancement</h5><p>It is defined as homogeneous enhancement of thickened bowel wall that equals to the muscle enhancement. It is useful in differentiating benign with malignant diseases.</p><h5>Water halo sign</h5><p>It corresponds to oedema in the submucosa (cf <a href="/articles/fat-halo-sign-inflammatory-bowel-disease">fat halo sign</a> where there is fat infiltrating the submucosa). It may be seen in three forms:</p><ul>
  • +</ul><h5>Gray enhancement</h5><p>It is defined as homogeneous enhancement of thickened bowel wall that equals to the muscle enhancement. It is useful in differentiating benign from malignant diseases.</p><h5>Water halo sign</h5><p>It corresponds to oedema in the submucosa (cf <a href="/articles/fat-halo-sign-inflammatory-bowel-disease">fat halo sign</a> where there is fat infiltrating the submucosa). It may be seen in three forms:</p><ul>
  • -</ul><h5>Fat halo sign</h5><p>It represents infiltration of the submucosa with fat, between the muscularis and the mucosa.</p><p>It is considered pathognomonic for <a href="/articles/inflammatory-bowel-disease-ibd">inflammatory bowel disease</a>.</p><h5>Black attenuation</h5><p>It is synonymous with <a title="Pneumatosis intestinalis" href="/articles/intramural-bowel-gas">pneumatosis </a>and the causes include:</p><ul>
  • +</ul><h5>Fat halo sign</h5><p>It represents infiltration of the submucosa with fat, between the muscularis and the mucosa.</p><p>It is considered pathognomonic for <a href="/articles/inflammatory-bowel-disease-ibd">inflammatory bowel disease</a>.</p><h5>Black attenuation</h5><p>It is synonymous with <a href="/articles/intramural-bowel-gas">pneumatosis</a> and the causes include:</p><ul>

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