How Long Does an MRI Take?
Quick Answer
15–90 minutes depending on the body part scanned. A brain MRI takes 20–45 minutes; a knee MRI takes 15–30 minutes.
Typical Duration
Quick Answer
Most MRI scans take 15–90 minutes, with the average exam lasting about 30–60 minutes. Scan time depends on the body part being imaged, whether contrast dye is used, and the number of sequences needed. A simple knee MRI can be done in 15–30 minutes, while a full-body or multi-region scan can take up to 90 minutes.
MRI Time by Body Part
| Body Part | Without Contrast | With Contrast |
|---|---|---|
| Brain | 20–30 minutes | 30–45 minutes |
| Knee | 15–30 minutes | 25–40 minutes |
| Spine (single region) | 20–35 minutes | 30–45 minutes |
| Spine (full) | 45–60 minutes | 60–75 minutes |
| Shoulder | 20–30 minutes | 30–45 minutes |
| Hip | 20–30 minutes | 30–40 minutes |
| Abdomen/pelvis | 30–45 minutes | 45–60 minutes |
| Heart (cardiac MRI) | 45–60 minutes | 60–90 minutes |
| Breast | 30–45 minutes | 40–60 minutes |
| Full body | 60–90 minutes | 75–90+ minutes |
With Contrast vs Without Contrast
Contrast-enhanced MRIs use gadolinium, a dye injected into a vein through an IV. It highlights blood vessels, tumors, and areas of inflammation. Adding contrast typically adds 10–20 minutes to the total exam time because the technologist runs one set of sequences before the injection and another set after.
Your doctor will order contrast when they need to:
- Evaluate tumors or distinguish scar tissue from active disease
- Assess blood flow to organs or the brain
- Look at blood vessel abnormalities (MRA)
- Check for infections or inflammatory conditions
Open MRI vs Closed MRI
| Feature | Closed MRI | Open MRI |
|---|---|---|
| Scan time | 15–90 minutes | 20–120 minutes |
| Image quality | Higher resolution | Somewhat lower resolution |
| Bore size | 60–70 cm diameter tunnel | Open on 2–4 sides |
| Best for | Most diagnostic needs | Claustrophobia, larger patients |
| Noise level | Loud (up to 110 dB) | Somewhat quieter |
Open MRI machines use weaker magnets (0.2–1.0 Tesla vs 1.5–3.0 Tesla for closed), so they require longer scan times to produce comparable images.
What the Total Visit Looks Like
The scan itself is only part of the appointment. Here’s what to expect for total time at the facility:
| Step | Time |
|---|---|
| Check-in and paperwork | 10–15 minutes |
| Change into gown, remove metal | 5–10 minutes |
| Positioning on the table | 5–10 minutes |
| The MRI scan | 15–90 minutes |
| IV placement (if contrast) | 5 minutes |
| Post-scan review by tech | 5 minutes |
| Total visit | 45 minutes–2 hours |
Preparation Tips
- Wear comfortable clothing without metal zippers, snaps, or underwire. Many facilities provide a gown.
- Remove all metal including jewelry, watches, hair clips, hearing aids, and belts before entering the scan room.
- Ask about earplugs or headphones – MRI machines are loud (knocking, buzzing, and thumping sounds). Most facilities offer hearing protection and some allow music.
- Stay still – movement blurs the images and may require repeating sequences, extending your scan time.
- Inform your technologist if you are claustrophobic. Mild sedation or an open MRI may be options.
- Fasting: Only required for certain abdominal or pelvic scans – your ordering physician will specify.
How Long for Results?
A radiologist typically reads the images and sends a report to your doctor within 24–48 hours. Urgent scans may be read the same day.