Which diagnostic test is appropriate for diverticulitis?

A CT scan is the most appropriate diagnostic test for diverticulitis due to its high sensitivity and specificity for detecting the condition and its complications. This imaging modality allows for the visualization of the bowel wall and can identify diverticula, pericolic inflammation, abscess formation, and other related complications such as perforation. CT scans also provide a comprehensive view of the abdomen, which helps differentiate diverticulitis from other abdominal conditions that may present with similar symptoms.

In contrast, while ultrasound can sometimes be used, particularly in certain populations like pregnant women or those who wish to avoid radiation, it is generally less reliable for diagnosing diverticulitis. A barium enema is not recommended for acute diverticulitis because it can lead to complications, such as perforation. MRCP, which is primarily used for imaging the biliary and pancreatic ducts, is not relevant for diagnosing diverticulitis, as it does not provide necessary information about the colonic structure. Thus, the CT scan stands out as the best tool for confirming a diagnosis of diverticulitis due to its effectiveness and the critical information it provides.