Abnormal bowel wall attenuation patterns
Updates to Article Attributes
Abnormal bowel wall attenuation patterns on CT scan can be grouped under five categories:
- white enhancement
- gray enhancement
- water halo sign
- fat halo sign
- 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:
- inflammatory bowel disease
- vascular disorder
Gray enhancement
It is defined as a homogeneous enhancement of thickened bowel wall that equals to the muscle enhancement. It is useful in differentiating benign from 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 the inner oedematous layer
- inner hyperattenuating layer with outer oedematous layer
- oedematous submucosa between two hyperattenuating layers (target sign)
Common differentials include:
- 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 suggestive of inflammatory bowel disease, but may be seen in normal adults.
Black attenuation
It is synonymous with pneumatosis and the causes include:
- trauma
- ischaemia
- infection
-<li>fat halo sign</li>- +<li><a title="Fat halo sign (inflammatory bowel disease)" href="/articles/fat-halo-sign-inflammatory-bowel-disease">fat halo sign</a></li>
-</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>-<li>outer hyperattenuating layer with inner oedematous layer</li>- +</ul><h5>Gray enhancement</h5><p>It is defined as a 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>
- +<li>outer hyperattenuating layer with the inner oedematous layer</li>
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