Acute colonic diverticulitis (ACD) is one of the presentations of diverticular disease and a complication of colonic diverticulosis. Contrast-enhanced computed tomography (CE-CT) is the modality of choice for the diagnosis and staging of colonic diverticulitis. The new radiological classification system (WSES guidelines) is based on modified Hinchey’s classification, and divides ACD into uncomplicated and complicated: the first is characterized by segmental bowel wall thickening, and pericolonic fat stranding; the latter is characterized by abscess formation, intestinal perforation, peritonitis, fistulas, and ascending septic thrombophlebitis and is divided into 4 stages.