CTAbdomen

Computed tomography of the abdomen, commonly abbreviated CT abdomen, is a cross-sectional imaging modality that uses X-rays and computer reconstruction to visualize abdominal organs from the diaphragm to the pelvis. It may be performed with or without intravenous contrast and, depending on the indication, with oral or rectal contrast or as a multiphasic study.

Indications for CT abdomen include evaluating acute abdominal pain, suspected appendicitis, diverticulitis, bowel obstruction, inflammatory bowel disease, intra-abdominal infection, trauma, abdominal masses, hemorrhage, and cancer staging or treatment planning. Non-contrast CT is often preferred for detecting renal calculi or calcifications.

Technique and protocol vary by indication. Modern CT uses rapid helical scanning with multiplanar reformats. Common protocols include non-contrast, arterial, and portal venous phases, with intravenous iodinated contrast typically used. Oral or rectal contrast may aid evaluation of the bowel lumen but can be omitted in emergencies. CT angiography is used to assess arterial or venous vessels.

Safety, preparation, and limitations are important considerations. Radiation exposure is a concern, especially for younger patients. Contrast administration carries risks of allergic reaction and, in those with reduced renal function, contrast-induced nephropathy; renal function is often assessed before contrast administration. Hydration and, in select cases, premedication may be employed. While CT provides high diagnostic accuracy for many abdominal conditions, it may miss subtle findings and can reveal incidental abnormalities.

Interpretation and reporting are performed by radiologists, who describe findings, offer differential diagnoses, and recommend follow-up or additional imaging. Alternatives include ultrasound, especially in pediatrics or biliary disease, and magnetic resonance imaging when radiation avoidance or detailed tissue characterization is needed.