Open vs Closed MRI: Which Should You Choose?

Choosing between an open MRI and a closed MRI is one of the most common questions patients have when booking a scan. Closed scanners produce sharper images but can trigger claustrophobia. Open scanners offer more space but have traditionally had lower image quality. Modern open-bore designs blur this line further. This guide compares all three scanner types so you can make the right choice. Book with Mira and select the scanner type that works best for you.

Open vs Closed MRI: Key Differences

The three main MRI scanner designs differ in their physical shape, magnetic field strength, and patient experience. Here is a direct comparison.

How Closed MRI Scanners Work

A closed MRI scanner is the traditional design that most people picture when they think of an MRI machine. It consists of a horizontal tube (bore) approximately 55 to 60 cm in diameter. You lie on a table that slides into the centre of this tube.

Advantages of Closed MRI

• Highest image quality: 1.5T and 3T field strengths produce the sharpest, most detailed images
• Best for complex studies: Brain, spine, prostate mpMRI, cardiac MRI, and any scan requiring multiple advanced sequences
• Fastest scan times: Higher field strength means faster signal acquisition, resulting in shorter scan durations
• Widest availability: Most hospitals and imaging centres use closed scanners, giving you the most appointment options
• Best for contrast studies: Contrast-enhanced imaging benefits from the higher signal-to-noise ratio of closed systems

Disadvantages of Closed MRI

• Claustrophobia: The narrow bore and enclosed design cause anxiety in 5% to 15% of patients. Approximately 2% cannot complete the scan.
• Size limitations: Standard closed scanners have weight limits of 250 to 350 lbs and bore diameters that may be tight for larger patients.
• Noise: Closed scanners at higher field strengths are louder than lower-field open systems.

How Open MRI Scanners Work

An open MRI scanner has a fundamentally different design. Instead of a closed tube, the magnet is positioned above and below the patient, with the sides open. You lie on a table between two flat magnetic plates.

Advantages of Open MRI

• Claustrophobia-friendly: The open design is significantly less anxiety-inducing. Patients can see out on both sides.
• Higher weight capacity: Open scanners typically accommodate patients up to 350 to 500 lbs.
• Comfortable for larger patients: No narrow tube to squeeze into.
• Child-friendly: Parents can sometimes stay close to the child during the scan.
• Positioning flexibility: Some open scanners allow upright or seated positioning for specialised studies.

Disadvantages of Open MRI

• Lower field strength: Traditional open scanners operate at 0.2T to 0.7T, compared to 1.5T or 3T for closed systems. This means lower image resolution.
• Longer scan times: Lower field strength requires longer acquisition times, extending the scan by 10% to 30%.
• Limited for some studies: Brain diffusion imaging, prostate mpMRI, cardiac MRI, and some other advanced protocols may not be feasible on low-field open systems.
• Less available: Fewer centres offer open MRI compared to standard closed scanners.

Modern high-field open scanners (1.0T to 1.5T) have closed much of the image quality gap. However, they are less common and more expensive to manufacture, so availability is limited.

Open-Bore MRI: The Middle Ground

Open-bore (also called wide-bore) MRI scanners represent a compromise between closed and open designs. They use the same cylindrical design as closed scanners but with a significantly wider bore: typically 70 to 75 cm compared to 55 to 60 cm.

• Image quality: Equivalent to standard closed scanners because they use the same field strength (1.5T or 3T).
• Comfort: The wider bore provides substantially more space. Most patients who are uncomfortable in standard closed scanners can tolerate an open-bore scanner.
• Weight capacity: Typically 350 to 550 lbs, higher than standard closed scanners.
• Advanced studies: Capable of all the same protocols as standard closed scanners, including brain, spine, prostate mpMRI, and cardiac imaging.
• Scan times: Same as standard closed scanners.

Open-bore scanners are increasingly common and represent the best option for patients who need high image quality but find standard closed scanners uncomfortable.

Which Scanner Is Best for Your Scan?

The best scanner type depends on two factors: the clinical question (what your scan needs to show) and your comfort requirements.

For routine musculoskeletal scans (knee, shoulder, hip, ankle), all three scanner types produce diagnostically adequate images. For brain, abdominal, and specialist studies, closed or open-bore scanners are preferred.

MRI Scanner Options at Mira Locations

UK - Kent (Bluewater, Dartford)

Mira scans in Kent take place at Mira Scanning Centre, Bluewater, Dartford, which operates a clinical-grade MRI scanner. Contact the team or check at booking for specific scanner specifications and availability.

US - Houston

Mira operates three scanning centres across Houston, each with a different scanner type.

If claustrophobia or weight is a concern, the Spring and Dickinson locations are the best options. If maximum image quality is the priority and you are comfortable in a closed scanner, the Central Houston location is excellent.

Claustrophobia and MRI: Practical Tips

If claustrophobia is your primary concern about MRI, you have more options than you might think.

• Try an open-bore scanner first: The wider bore solves the problem for most patients who struggle with standard closed scanners.
• Enter feet-first: For many scans (spine, hip, knee, ankle), you can enter the scanner feet-first, keeping your head near the opening.
• Close your eyes: Before the table moves into the scanner, close your eyes and keep them closed throughout. This prevents the visual trigger of seeing the bore walls close to your face.
• Use headphones with music: Engaging your auditory attention with music reduces the focus on the scanning environment.
• Breathing exercises: Slow, rhythmic breathing (4 counts in, 4 counts out) helps manage anxiety.
• Take a companion: Most centres allow a family member to sit in the control room, visible through the glass.
• Sedation: For severe claustrophobia, your doctor can prescribe a short-acting anxiolytic (diazepam or lorazepam). You will need someone to drive you home.
• Practice at home: Lie in a dark, quiet room with your eyes closed for 15 to 20 minutes to simulate the scan experience.

Open vs Closed MRI: Cost Comparison

The cost difference between open and closed MRI varies by provider and location.

• NHS (UK): Free regardless of scanner type, but you cannot choose your scanner.
• Private UK: Prices are generally the same regardless of scanner type. With Mira, scans start from £369.
• US hospitals: Costs are similar for both scanner types, though some hospital systems charge a premium for open MRI due to longer scan times.
• US imaging centres: Generally the same price. Mira offers all scanner types from $369.

With Mira, all scanner types are available at the same price point. Your choice should be based on clinical need and comfort, not cost.

Image Quality: Does It Matter For Your Scan?

The image quality difference between scanner types is real but often overstated for routine diagnostic scans.

• For routine knee, shoulder, hip, and ankle MRI: The image quality from any modern scanner (including lower-field open systems) is diagnostically sufficient. Radiologists regularly produce accurate diagnoses from 0.7T and above.
• For brain, spine, and abdomen: 1.5T or higher is preferred. Modern open-bore scanners at 1.5T produce identical quality to standard closed 1.5T systems.
• For specialist studies (prostate mpMRI, cardiac, diffusion imaging): 1.5T minimum, 3T preferred. Only closed or open-bore scanners are suitable.

The radiologist reading your scan is as important as the scanner itself. An experienced radiologist can produce an accurate diagnosis from images across all scanner types. All Mira scans are interpreted by consultant radiologists, and every scan comes with two reports delivered within 3 working days: a medical report and a miraclarity report in plain English.

Open vs Closed MRI: Scan Time Differences

One practical difference between scanner types that patients should be aware of is scan duration.

• Closed MRI (1.5T/3T): Fastest scan times. A knee MRI takes 25 to 35 minutes. Higher field strength means faster signal acquisition.
• Open-bore MRI (1.5T/3T): Same scan times as standard closed scanners because the field strength is identical.
• Open MRI (low-field, 0.2-0.7T): 10% to 30% longer scan times. A knee MRI that takes 30 minutes on a closed scanner may take 35 to 40 minutes on a low-field open system.
• The difference is usually 5 to 15 minutes per scan. For most patients, the comfort benefit of an open scanner outweighs the slightly longer scan time.

If scan duration is a concern (for example, if lying still is painful), an open-bore scanner at 1.5T offers the best combination of fast scan times and patient comfort.