Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic technique that produces detailed images of the body using a strong magnetic field and radiofrequency waves. Generally, the higher the Tesla (T) rating of the MRI scanner, the more detailed and faster the imaging process. However, because higher Tesla scanners are more sensitive they can also be more susceptible to image artifacts.
In the UK, there are approximately 1,300 MRI units per million people, consistent with typical rates across Europe but roughly 10% of the per capita MRI availability in the USA. Globally, there are around 50,000 installed MRI scanners, with approximately 5,000 new units added annually. As of 2024, 624 MRI units were reported in use across the UK, and this number is projected to double within the next five years.
MRI Anaesthesia
Not every MRI facility is equipped with an MRI-compatible anaesthesia machine, but the demand is growing. MRI anaesthesia is required in several scenarios, including:
- Paediatric, nervous, or claustrophobic patients
- Trauma cases
- Intraoperative MRI
- Patients requiring sedation or general anaesthesia during imaging
Magnetic Field Considerations for Anaesthesia Equipment
Operating within an MRI environment presents safety and technical challenges:
- Projectile risk: Ferromagnetic components can be pulled toward the magnet, endangering patients and staff.
- Medical device malfunction: Magnetic fields can affect the functionality of anaesthesia equipment, such as interfering with control valves.
- Image artifacts: Electromagnetic interference from nearby equipment, such as Anaesthesia systems, can degrade MRI image quality.
A common misconception is that the strength of the magnetic field at a given location is directly proportional to the scanner's Tesla rating (e.g., 1.5T, 3T, 5T, 7T). However, the real determinant of safe equipment positioning is the local magnetic field strength, measured in Gauss. Magnetic shielding varies between MRI models and manufacturers, which is why equipment should be evaluated based on Gauss ratings and the specific MRI environment, referring to the Gauss map of the installation.
Most MRI-compatible anaesthesia machines are rated for placement in areas of up to 200 Gauss or 400 Gauss. The Penlon Prima 451 MRI Anaesthesia System, however, is certified for use in magnetic fields up to 1,000 Gauss. This higher tolerance allows the system to be positioned closer to the magnet, improving anaesthetist access and patient management during procedures.
We believe this, along with the system’s low magnetic attraction and reduced impact on image quality, makes the Penlon Prima 451 one of the safest and most efficient choices for MRI-compatible anaesthesia delivery
A Typical Gauss Map
Penlon Prima 451 MRI Anaesthesia System – Competitive Advantages
- MRI Compatibility:
- Certified for use with 0.55T, 1.5T, 3T, 5T, and 7T MRI systems
- Approved by major MRI manufacturers including GE, Philips, Siemens, and United Imaging
- Enhanced Safety:
- Rated for use up to 1,000 Gauss
- Low magnetic attraction
- Minimal MRI image artifacts
- Clinical Versatility:
- Suitable for all patients from neonates to adults
- The availability of multiple ventilation modes including Pressure Support Ventilation (PSV) with backup, and Pressure-Regulated Volume Control (PRVC)
- User-Friendly:
- Intuitive interface designed for ease of use
- Operational Efficiency:
- Gauges for both cylinder and pipeline gas supply
- Low total cost of ownership
- Optional training available to UK hospitals for in-house servicing and maintenance
- Reliable, reusable spirometry sensors
Recommendations for Medical Technicians
- Always verify the Gauss rating of any equipment used in the MRI environment.
- Be aware of the Gauss zones around your scanner defined by the installation’s Gauss map.
- Ensure regular training on MRI safety protocols, especially when using or moving MRI-compatible equipment.
- Familiarise yourself with manufacturer certifications for MRI compatibility.
- When in doubt, consult the MRI safety officer.
Craig Thompson 25 Sept 2025
