The amount of time an MRI scan of the brain takes can vary depending on the type of scan, the area being imaged, and the radiology facility. However, most standard brain MRI scans take between 30 and 60 minutes to complete.
Quick Overview
In general:
- A standard structural brain MRI scan takes 30-60 minutes
- Functional MRI scans take 60-90 minutes
- Diffusion MRI scans take 30-60 minutes
- MR spectroscopy scans take 30-60 minutes
The technologist should inform you of the expected scan time when you schedule your appointment. Plan to be at the imaging center for up to 90 minutes for the entire process including setup, scan time, and time to change back into your clothes.
What Affects Brain MRI Scan Time?
There are several factors that determine how long a brain MRI scan takes:
Type of Scan
Different types of brain MRI scans require different amounts of scan time:
- Structural MRI: 30-60 minutes. Structural scans provide images of the brain’s anatomy and are used to look for tumors, bleeding, and anatomical abnormalities.
- Functional MRI (fMRI): 60-90 minutes. Functional MRI looks at brain activity and connectivity when performing cognitive tasks. It requires more scan sequences.
- Diffusion MRI: 30-60 minutes. Diffusion MRI looks at the movement of water molecules in the brain to map the brain’s white matter tracts.
- MR Spectroscopy: 30-60 minutes. Spectroscopy scans measure brain metabolites and help diagnose disorders like brain tumors.
Area Being Imaged
Scanning a larger portion of the brain takes more time. A scan of the entire brain takes longer than a scan looking just at a specific area, like the pituitary gland.
Number of Sequences
Each set of images acquired during an MRI scan is called a sequence. Structural scans usually require 5-6 sequences while functional scans may require 8 or more. The more sequences, the longer the scan will take.
Resolution
Higher resolution images have more detail but require longer scan times to acquire. Scans done for research or 3D modeling often require longer times for high resolution.
Radiology Center Factors
The type of MRI machine, scheduling protocols, and technologist experience can all impact scan times at different radiology centers.
Average Scan Times by MRI Type
Here is a table summarizing typical MRI scan times for different types of brain imaging:
| MRI Scan Type | Typical Scan Time |
|---|---|
| Structural MRI | 30-60 minutes |
| Functional MRI | 60-90 minutes |
| Diffusion MRI | 30-60 minutes |
| MR Spectroscopy | 30-60 minutes |
Factors That May Increase Scan Time
While standard brain MRI scans take 30-60 minutes, there are some situations where more time may be needed:
- Motion artifacts – If movement degrades image quality, additional sequences may be needed.
- Use of contrast – administering IV contrast dye adds about 10-15 minutes.
- Small children – Children often require sedation for MRI which adds time.
- Specific research protocols – Research scans may require specialized or additional sequences.
How to Prepare for Your Brain MRI
You can help your brain MRI go smoothly and minimize repeat scans by:
- Arriving early for your scheduled time.
- Following all instructions for medications and food/drink.
- Keeping very still during the scan – motion can degrade images.
- Wearing comfortable clothing without metal fasteners or details.
- Informing your technologist if you have any implants, devices, or medical conditions like claustrophobia.
What to Expect During Your Brain MRI
Knowing what to expect during your brain MRI can help you stay calm and relaxed:
- You will be asked to change into a hospital gown to avoid any metal interference.
- MRI staff will explain the scan process and insert an IV if contrast is needed.
- You will lie on a movable exam table that slides into the MRI scanner tunnel.
- Padding and restraints may be used to help you stay still.
- You will hear loud tapping or knocking sounds during the actual imaging.
- You will be given a call button in case you need help or feel uncomfortable.
- You will be able to communicate with the technologist over an intercom system.
Tips for Staying Comfortable
- Wear earplugs provided by the imaging center if the noise bothers you.
- Keep your eyes closed to minimize claustrophobia.
- Breathe deeply and evenly to relax.
- Listen to the rhythmic knocking sound and visualize yourself somewhere peaceful.
- Tell the technologist immediately if you feel anxious or overheated.
After Your Brain MRI Scan
Once your scan is complete, the table will slide back out of the scanner. The technologist will remove any restraints or contrast lines. You will then be able to change back into your regular clothes. The scan images will be processed by a radiologist, who will write up an interpretation of the results. This MRI report will be sent to your doctor, who will then discuss the findings with you at a follow up appointment.
It’s normal to feel relief and perhaps some fatigue after your scan. Be sure to drink fluids and rest once you return home. If you had contrast dye, increase your water intake to help flush it from your system. While most people can resume normal activities right away, your doctor may recommend limiting vigorous exercise for the remainder of the day.
Frequently Asked Questions
Why does a brain MRI take so long?
MRIs require taking multiple images of the brain from different angles and using different pulse sequences. This scanning time is needed to get clear, high quality images across the entire brain. The computer also needs time to process the data between sequences. Better image quality leads to more accurate results.
Can I listen to music during the scan?
You usually cannot listen to music directly during the scan because the MRI magnets interfere with electronics like headphones. Some facilities may have special MRI-compatible music systems or provide music through earplugs. However, many centers prefer no music so patients can hear instructions.
How do I stay comfortable in the scanner?
The technologist will provide blankets, padding, and restraints as needed for comfort. Let them know if you feel any pain or overheating. You can also request a cloth or towel to place over your face if you feel claustrophobic. Focus on breathing slowly and deeply.
Can I have someone sit with me during the scan?
For safety reasons, no one is allowed in the MRI room during the actual imaging process. However, many facilities have viewing windows so a friend or relative can watch you from the adjacent room. Technologists are also in constant communication through the intercom.
What happens if I move during the scan?
Your technologist will be watching closely for any motion. If movement degrades the images, they may pause the scan and remind you to hold still before taking additional sequences. However, some minor movement is common and the scans may still be usable.
Conclusion
Most standard, non-emergency brain MRI scans take between 30 and 60 minutes. This allows time to obtain multiple sequences and high quality images necessary for an accurate diagnosis. While the exact time depends on the machine, protocols, and sequences needed for your particular medical situation, your radiology center can provide an estimate when you schedule. Being prepared for the scan procedures, following instructions, and using relaxation techniques can help you remain comfortable for the full scan time.