How Long Does a CT Scan Take?

Quick Answer

A CT (computed tomography) scan itself typically takes 10–30 minutes depending on the body part being scanned and whether contrast dye is used. The actual imaging often takes only 1–5 minutes, but preparation, positioning, and post-scan observation add to the total appointment time. Expect to be at the imaging center for 30 minutes to 2 hours overall.

Scan Time by Body Part

The area being scanned significantly affects how long the process takes:

Body Part	Scan Time (Without Contrast)	Scan Time (With Contrast)
Head/Brain	5–10 minutes	15–20 minutes
Chest	5–10 minutes	15–25 minutes
Abdomen/Pelvis	10–15 minutes	20–30 minutes
Spine	10–15 minutes	15–25 minutes
Full Body	15–20 minutes	25–30 minutes
CT Angiography	10–15 minutes	20–30 minutes
Cardiac CT	10–20 minutes	20–30 minutes

These times reflect how long you will be on the scanner table. The machine actually captures images in seconds, but repositioning, breathing instructions, and multiple scan passes add time.

With vs. Without Contrast

Contrast dye (usually iodine-based) is injected intravenously to highlight blood vessels, organs, and abnormalities. It significantly affects the total appointment length:

Without contrast:

• Minimal preparation
• Total appointment: 30–45 minutes
• You can typically eat and drink normally before

With contrast:

• An IV line must be placed before scanning
• You may need to fast for 4–6 hours beforehand
• Blood work (creatinine level) may be required to check kidney function
• A 15–30 minute observation period follows the scan
• Total appointment: 1–2 hours

Some scans require both a non-contrast and contrast series, which adds time as the scan is performed twice.

What to Expect During the Scan

Here is a step-by-step breakdown of the appointment:

1. Check in and change into a hospital gown if needed (5–10 minutes)
2. IV placement if contrast is required (5–10 minutes)
3. Positioning on the scanner table by the technologist (5 minutes)
4. The scan itself: you lie still while the table moves through the donut-shaped scanner (1–15 minutes)
5. Post-scan observation if contrast was used (15–30 minutes)

During the scan, you may be asked to hold your breath for 10–20 seconds at a time, particularly for chest and abdominal scans. The technologist communicates through a speaker and can see you at all times through a window.

Preparation Tips

• Wear comfortable, metal-free clothing to avoid needing to change
• Remove all jewelry and metal objects including belts, glasses, and hearing aids
• Follow fasting instructions if provided (typically 4–6 hours for contrast scans)
• Inform your doctor if you have kidney problems, diabetes, are pregnant, or have had allergic reactions to contrast dye
• Stay hydrated before and after a contrast scan to help flush the dye from your system
• Arrive 15–20 minutes early for paperwork and preparation

How Long Until You Get Results

The radiologist typically interprets the images within 24–48 hours for non-urgent scans. Emergency room CT scans are read within 1–2 hours or faster. Your referring doctor will then contact you to discuss the findings. Some facilities offer patient portals where results are available within 1–3 business days.

CT Scan vs. Other Imaging

Compared to other imaging methods, CT scans are among the fastest:

• X-ray: 5–15 minutes
• CT scan: 10–30 minutes
• Ultrasound: 15–45 minutes
• MRI: 30–90 minutes
• PET scan: 2–3 hours

This speed makes CT scans the preferred choice in emergency situations where rapid diagnosis is critical, such as stroke, internal bleeding, or trauma evaluation.