The most common cause of left lower abdominal pain in adults is diverticulitis , an inflammation of outpouchings that can develop in the colon. It is usually appropriate to get a CT with intravenous (IV) contrast of the lower abdomen and pelvis to confirm the diagnosis. Other imaging tests that may be appropriate include CT without IV contrast, ultrasound of the abdomen, and MRI of the abdomen. Unless complications are suspected, barium enema, abdominal X-ray, and ultrasound of the pelvis are usually not appropriate as the first imaging test.
Some possible complications of diverticulitis are blockage of the colon (obstruction), a hole in the colon (perforation), an abscess (an infected fluid collection in the abdomen), or a fistula (an abnormal connection from the colon to other structures). If the health care team suspects complications, CT with IV contrast is usually the most appropriate imaging test.
For people with suspected complications, CT without IV contrast, CT with bladder contrast, barium enema, or cystography (x-ray images with bladder contrast) may also be appropriate.
Some individuals may not need a CT if their health care team has determined that the symptoms are typical of diverticulitis without complications or if the person has a history of diverticulitis and is having a recurrence. These individuals may be treated without any imaging. For more information, see the Diverticulitis page.