The differential diagnosis of left lower-quadrant
pain includes gastrointestinal, gynecologic, and renal/ureteric pathology. Imaging is helpful in evaluating left lower-quadrant
pain, and is generally guided by the clinical presentation. Acute sigmoid
diverticulitis should be suspected when the clinical triad of left lower-quadrant
pain,
fever, and
leukocytosis is present. The severity of disease varies from mild pericolonic and peridiverticular
inflammation to severe inflammatory changes with complications such as perforation,
peritonitis, or
abscess or
fistula formation. Computed tomography is the preferred test in evaluating clinically suspected
diverticulitis. It is used to evaluate the severity and extent of disease and to identify complications, but it also may diagnose other causes of left lower-quadrant
pain that can mimic
diverticulitis. Magnetic resonance imaging can be used to assess left lower-quadrant
pain. It has superior resolution of soft tissues and does not expose the patient to ionizing radiation, but it is expensive and requires more time to perform. Transabdominal ultrasonography with graded compression is another effective technique but is limited by its high operator dependency and technical difficulties in scanning patients who are obese. Pelvic ultrasonography is the preferred imaging modality in women of childbearing age. Radiography with contrast
enema is less sensitive than computed tomography in diagnosing
diverticulitis and is seldom used.