What Does Diverticulitis on a CT Scan Mean?

When a CT report says diverticulitis, it means the scan shows signs of inflammation or infection around diverticula, the small pouches that can form in the wall of the large bowel. CT is often used because it is quick and can show both how far the inflammation extends and whether there are complications, which helps decide where and how it is treated.

Having pouches without inflammation is called diverticulosis and is common; that pattern is covered in the guide on diverticulosis seen on colonoscopy. This guide is for adults who have a CT report mentioning diverticulitis and want to understand the wording and prepare questions. It cannot judge your own scan or decide treatment.

A CT result does not replace how you feel now. If symptoms change after the scan, seek help rather than waiting for a routine appointment. The NHS advice below is a guide; use your local urgent or emergency services.

• Call emergency services or go to an emergency department for severe tummy pain with vomiting, a swollen tummy, being unable to pass stools or wind, or heavy bleeding from the bottom.
• Signs of possible sepsis, such as confusion, pale or blotchy skin, a very high or low temperature or fast breathing, also need emergency care.
• Get urgent advice the same day if tummy pain is getting worse or not going away, you have a high temperature, you keep vomiting, or you notice blood or mucus in your poo.
• Cleveland Clinic also lists a rigid, tender abdomen, fresh blood in the stool, and paleness or weakness as warning signs.

Most cases are uncomplicated: there is inflammation, but no secondary problems. Cleveland Clinic describes diverticulitis as becoming complicated when the inflammation begins to cause further problems.

Complications that CT can help identify, and that NHS, NIDDK and Cleveland Clinic describe, include:

• an abscess, a collection of pus next to the bowel
• a perforation, a hole in the bowel wall
• a fistula, an abnormal channel between the bowel and another organ such as the bladder
• a blockage (obstruction) of the bowel
• peritonitis, infection of the lining of the abdomen, which can lead to sepsis

Diverticulitis symptoms, such as constant tummy pain and fever, overlap with other conditions. The American Gastroenterological Association (AGA) advises that CT should be considered to confirm the diagnosis in people who have not had diverticulitis confirmed on imaging before. CT is also suggested to look for complications when symptoms are severe, do not improve with treatment, or someone is immunocompromised.

CT also looks at nearby organs, which helps rule out other causes of pain. It does have limits: RadiologyInfo notes, for example, that gallstones may be better seen on ultrasound. If your CT was normal but pain continues, the guide on abdominal pain with a normal CT scan may help.

Not always. NIDDK says not all people with diverticulitis need antibiotics, and people without complications may be treated at home. The AGA clinical practice update says antibiotics can be used selectively, rather than routinely, in people with a healthy immune system who have mild, uncomplicated diverticulitis.

The same guidance advises antibiotics for complicated diverticulitis, and for uncomplicated cases in people with other illnesses, frailty, symptoms that do not settle, vomiting or markedly raised inflammation markers. Antibiotics are strongly advised for people who are immunocompromised. Your clinician weighs these factors with you.

If you have been prescribed antibiotics, do not stop them early or change how you take them without talking to the prescriber. NIDDK also describes a short period of clear liquids, with solid food reintroduced as symptoms improve, when recommended by the doctor.

People with severe diverticulitis or complications usually need hospital care. NIDDK explains that small abscesses may be treated with antibiotics, while larger abscesses, or ones that do not improve, may be drained. Surgery may be recommended for complications such as perforation, fistula, obstruction or peritonitis, or when diverticulitis does not improve with treatment. The type and timing of any procedure is decided by the surgical and gastroenterology team.

Often, yes. A colonoscopy looks directly at the bowel lining and can help rule out other conditions, including cancer, that can sometimes look similar on a scan. The AGA advises colonoscopy after complicated diverticulitis and after a first uncomplicated episode, unless a recent high-quality colonoscopy (within a year) was done.

The AGA advises waiting 6 to 8 weeks, or until the acute symptoms have fully settled, whichever is longer, because the bowel needs time to heal. Colonoscopy may be considered sooner if there are alarm symptoms. Ask your team whether one is planned for you and who arranges it.

Keep a copy of the CT report and any discharge letter. If a colonoscopy is arranged, the team performing it will want to know about the episode, and having the dates and findings to hand avoids repeating tests unnecessarily.

Bring the full CT report, not just a portal summary saying diverticulitis, and note when your symptoms started, any fever and any bleeding. Reports often use technical terms; it is reasonable to ask the clinician to explain each one in plain words.

• Does my CT show uncomplicated or complicated diverticulitis, and what did it show about abscess or perforation?
• Do I need antibiotics in my situation, and why or why not?
• Which symptoms mean I should come back or seek emergency care?
• Do I need a colonoscopy afterwards, and when?
• Is there anything I should know about diet or recovery while symptoms settle?
• What should I do if symptoms come back after this episode, and who should I contact first?
• Did the scan show anything else that needs follow-up, separate from the diverticulitis?

On SameCase, patients and verified doctors share de-identified cases. Reading how others with a similar CT report described their treatment and follow-up can help you spot questions to bring to your appointment. Other people's cases cannot tell you what your scan means or how you should be treated; your own clinician makes those decisions with you.