CT Scan (Computed Tomography)

A CT scan combines X-ray images taken from different angles and uses computer processing to create cross-sectional images of bones, blood vessels, and soft tissues. Over 80 million CT scans are performed annually in the US. Modern multi-detector CT scanners can complete a scan in seconds.

CT scans are used for emergency evaluation (trauma, stroke, pulmonary embolism), cancer detection and staging, guiding biopsies and procedures, evaluating chest and abdominal conditions, and low-dose CT for lung cancer screening in high-risk patients.

You may need to fast for 4-6 hours if contrast dye is used. Inform your doctor if you have kidney disease, diabetes, or contrast allergies. Remove metal objects. Drink contrast solution if ordered for abdominal imaging.

You lie on a narrow table that slides through a doughnut-shaped scanner. The scan is very quick — often less than 30 seconds for the actual imaging. You may be asked to hold your breath briefly. IV contrast may be injected for enhanced detail, which may cause a warm sensation.

No recovery time needed. Resume all activities immediately. If IV contrast was used, drink plenty of fluids. If you have kidney disease, your kidney function may be checked after contrast administration.

CT scans involve ionizing radiation. A single CT delivers 2-20 mSv depending on the area scanned. Risks include radiation exposure (cumulative cancer risk, very small), contrast dye allergic reactions, and contrast-induced kidney injury in susceptible patients.

Alternatives include MRI (no radiation, better soft tissue detail), ultrasound (no radiation, limited applications), X-ray (lower radiation but less detail), and clinical observation for non-urgent conditions.

Covered by insurance when medically indicated. Prior authorization may be required for non-emergency scans. Low-dose CT lung cancer screening is covered annually for qualifying high-risk adults aged 50-80.