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AJR July 2016

The Current Role of Radiologic and Endoscopic Imaging in the Diagnosis and Follow-Up of Colonic Diverticular Disease

The role of radiologic and endoscopic imaging in diverticular disease of the colon is considered in an article published in the July 2016 issue of the AJR. In particular, the authors review the distinct clinical scenarios of diverticulitis and follow-up of colonic diverticular disease.

Q&A with Nicola Flor, University of Milan School of Medicine, San Paolo Hospital, Milan, Italy

Why is diagnostic imaging useful in tailoring appropriate treatment to a patient’s specific clinical situation?

The CT colongraphy (CTC) gives clinicians information helpful in choosing the best therapeutic management. In particular, CTC can help in making surgical decisions when there’s a presence of a marked wall thickening causing severe lumen stenosis, or when the clinician is diagnosing unknown complications such as fistulas. CTC can be crucial to patients who are candidates for elective surgery as it depicts the true colonic extent of the disease and provides detailed information about the colon’s anatomy.

What led your team to conclude that neither an oral or rectal contrast agent is truly necessary?

Our choice to avoid oral and rectal contrast agents in evaluating patients with acute diverticulitis is based on different considerations. The use of contrast agents was actually the rule in past decades when previous CT collimation negatively impacted CT spatial resolution. Oral contrast agents determine a significant delay in performing the exam and this fact is contraindicated in the ER when clinicians ask radiologists to be efficient and fast. Another drawback of these contrast agents is represented by the risk of evaluating patients with an unknown perforation. In our practice, we still use oral contrast agents when dealing with thin patients, and rectal contrast agents in selected cases suspected of complications such as a fistula.

Why does the role of colonoscopy after an episode of acute diverticulitis remain controversial?

Following discharge from the acute event, further assessment of the colon to exclude other diseases has been recommended, but this position is still subject to debate. A follow-up study, colonoscopy or CTC in alternative, seems to be particularly useful within the first year from the acute event, due to the higher risk of diagnosing a colorectal cancer.

Why is it advisable to modify the standard CTC protocol slightly in the setting of known complicated diverticular disease?

Actually, to introduce slight changes in standard CTC protocol can dramatically improve the quality of our exams, and that is particularly true in evaluating patients recovering from acute diverticulitis. For example, a right-lateral additional decubitus is useful to investigate adequately the sigmoid colon, and in particular to obtain detailed information about the real degree of wall thickening and lumen stenosis. While the use of a spasmolityc drug may be controversial in CTC, there is evidence of its efficacy in evaluating patients with diverticular disease. Finally, it is advisable to perform a pre-insufflation scan when the patient tells you before the exam about persistency of pain.