Imaging for abdominal pain

Acute severe abdominal pain — particularly with fever, vomiting that won't stop, rigid abdomen, or signs of shock — is an emergency. Go to an emergency department.

Outpatient imaging is appropriate for:

• Subacute or chronic abdominal pain that hasn't been explained
• Right-upper-quadrant pain suggesting gallbladder disease
• Suspected kidney stones once acute renal colic has stabilized
• Follow-up of a known mass, cyst, or chronic condition
• Pre-procedure planning

ACR Appropriateness Criteria support starting with ultrasound for right-upper-quadrant pain (gallbladder), with CT for most suspected acute appendicitis or diverticulitis in the emergency setting, and with MRI/MRCP for select pancreaticobiliary questions.

Abdominal ultrasound is the first-line study for evaluating the gallbladder, liver surface, kidneys, and free fluid. It uses no radiation and is well suited to right-upper-quadrant pain and to imaging in pregnancy.

Abdominal CT (often with IV contrast) is the workhorse for acute and subacute abdominal pain. It evaluates appendicitis, diverticulitis, kidney stones, bowel obstruction, abscess, and most solid organ pathology in a single study.

Abdominal MRI is used for select indications: pancreas and biliary tree evaluation, liver lesion characterization, and inflammatory disease follow-up when avoiding repeat radiation matters. It is generally a second-line test after ultrasound or CT.

An abdominal ultrasound evaluates:

• Gallbladder for stones, wall thickening, sludge
• Liver echotexture and lesions visible from the surface
• Kidneys for stones, hydronephrosis, and mass
• Common bile duct caliber

An abdominal CT evaluates the entire abdomen — solid organs, bowel, retroperitoneum, vasculature, and bones — and detects most causes of acute abdominal pain in adults. MRI provides exquisite soft-tissue contrast of the pancreas, liver, and biliary tree.

Cholelithiasis (gallstones) and cholecystitis — common cause of right-upper-quadrant pain after meals. Ultrasound is the test of choice.

Kidney stones — non-contrast CT detects most. Smaller stones pass; larger or obstructing stones may need urology referral.

Appendicitis — typically diagnosed in the ED with CT (adults) or ultrasound (children, pregnant patients).

Diverticulitis — diagnosed with CT; manages with antibiotics in most cases.

Bowel obstruction — CT is the standard test.

Hepatic steatosis — fatty liver, often detected incidentally on ultrasound or CT.

Pancreatic cyst or pancreatitis — pancreatitis is often diagnosed by labs and CT; cysts may need follow-up MRI/MRCP for characterization.

Reports are usually back within a day. Findings drive next steps — surgical consultation for cholecystitis or symptomatic gallstones, urology for obstructing kidney stones, GI for inflammatory bowel disease, and oncology pathways for suspected malignancy.

Abdominal ultrasound typically requires fasting for 6 hours; your scheduler will confirm. Abdominal CT often uses IV and oral contrast — plan for an extra 30 minutes for oral contrast prep. Bring your prescription, ID, and insurance card. See our CT abdomen/pelvis page and our abdominal ultrasound page for locations.