CT Case 047

There are multiple sigmoid diverticulum with associated inflammation.

Signs of inflammation that we see here are mural thickening and pericolic fat stranding.

The mural thickening is centred around the diverticula. The wall thickening involves hyper enhancement of the inner and outer layers and hypodense oedematous middle layer.

All of these features are classical of acute diverticulitis.

There is also a small localised collection along the colon. This probably represents a small contained perforation with abscess formation.

A close differential for acute diverticulitis is colonic malignancy, however this tends to have mural thickening which is not centred around a diverticulum.

This is a case of complicated diverticulitis.

Assessing whether the patient has complicated vs uncomplicated diverticulitis is important, as this has implications for management.

Features of uncomplicated diverticulitis include;

• Thickened and enlarged diverticula
• Surrounding fat stranding (tissues appear hazy)
• There may be inflammation of the nearby structures e.g., bladder (reactive inflammation)

Features of complicated diverticulitis include;

• Diverticular perforation. Extraluminal free air – easiest to see on bone or lung windows
• Abscess formation. Contrast enhancing collection of fluid +/- air
• Fistula formation

Treatment will depend on a number of factors, especially patient comorbidities and severity of the disease.

For localised disease, intravenous antibiotics therapy is usually sufficient. If there is complicated diverticulitis, emergency surgery is often required.

For this patient, given her co-morbidities and concurrent neutropenia, she was initially managed with broad spectrum IV antibiotics. However, due to failure to improve, both clinically and on repeat CT imaging, she went on to require a Hartmann’s procedure.