Top 8 Considerations When Redesigning MRI Suites

Featured in HealthTechZone.com, December 2014.

Magnetic resonance imaging (MRI) examinations have been an important diagnostic tool since the first commercial MRI became available in 1981.^[1],[2]

Unlike X-rays and CT scans, which are good at imaging bones and other dense objects in the body, MRIs can create detailed images of soft tissues like the brain, heart, spinal cord, breasts and ligaments. Add this to the fact that MRIs do not emit radiation and it is no wonder that an estimated 33.8 million MRI exams were performed in the United States in 2013.^[3]

With a steady increase of performed procedures, increased machine technology, and conforming to safety regulations, hospitals and imaging centers face numerous challenges when it is time to replace a machine. Knowing this, you give your old MRI machine a once-over for specs and manufacturer’s name, call them up and replace your old machine with a newer model. Problem solved! Right?

There are a variety of considerations that should be discussed when replacing MRI machines and updating the suites. Safety regulations, magnet type/quantity, and rigging (in and out) of machines are a few items Array addresses in this Top 8 List of considerations to guide healthcare organizations through successful MRI suite redesigns.

1. How many machines need to be replaced and operation of the suite.

Hutch MRI Suite Most hospitals cannot just close their imaging suite to make the replacement. Therefore, the hospital needs to assess the current MRI backlog with procedure cost to determine what they can take offline during construction and for how long while still providing proper patient care and reasonable wait times. During the replacement and redesign of Montefiore Medical Center’s Moses MRI suites, two MRI machines, one 1.5T and one 3T, were required to be operational at all times. Due to this requirement, Array designed a third Magnet room with a new machine and phased the project so only one existing MRI is under construction at a time, allowing two MRIs to be operational at all times. The result was three new MRIs, one 1.5T and two 3.0T magnets.

Federal regulations require hospitals to maintain radiologic services “according to needs of the patients.”^[4]For Montefiore, this meant a minimum of two operational MRI machines.

2. What is a Tesla and Why Do They Matter?

MRI requires a magnetic field that is both strong and uniform. Teslas (T) are the unit of measurement that refers to the magnetic field strengths. Field strength, which determines image quality and scan speed, is one parameter to consider when choosing an MRI system. While the majority of systems operate at high field strengths of 1.5T (the “gold standard”), most clinical magnets are superconducting, which requires liquid helium to lower the temperature of the magnet windings. Because there is no perfect field strength for all applications, consider what you use your machines for now and what you wish they did better.

MRI scans, which can show muscles, joints, bone marrow, blood vessels and nerves, are commonly used to examine the brain, head, neck, spine and extremities. In 2010, 89% of all US imaging sites performed brain, head and neck procedures, yielding 8.7 million procedures in this category alone.

If this type of procedure is common for your facility, consider a 3.0T machine. They can provide very high-resolution images that are clear and vivid, and can usually be done faster, decreasing overall scan time. These machines are ideal for scanning small bones, the brain, spine and heart.

The “gold standard” in a clinical setting is a 1.5T machine, which can provide high-resolution images at faster speeds than lower field machines. The most common, 1.5T machines are ideal for scanning abdomens and chests.

When shopping for new machines, consider a combination of a 1.5T machine and a 3.0T machine to cover an array of uses and provide better options for patients.

MRI Tesla vs. Field vs. Format Comparison

3. Strive for Wide, Keep it Closed, Hardly Ever Open

In addition to teslas, machine format should be a deciding factor when purchasing a new machine. Like choosing teslas, there is no “one size fits all”. Consider your patients, your tesla choice and the types of scan requests that are typical.

A true open MRI utilizes fixed magnets, operates on a low- to mid-field strength and is open on all sides with two flat magnets above and beneath patients, providing a spacious environment for patients. Because of their lack of strength, open MRIs are not preferred, though they are ideal for larger patients and can alleviate claustrophobia.

A closed-bore MRI operates on high-field strength, producing high-resolution images. However, its opening is 60 cm, not ideal for claustrophobic or larger patients.

A wide-bore MRI, which also operates on high-field strength, is not open on all sides and creates high-resolution images, does not have a wider field of view than a closed-bore. However, patients lay in a 70 cm “hole”, providing a more comfortable atmosphere that helps reduce the number of claustrophobic issues.

4. Get in the Zone, Safety Zones

Once your machines have been chosen, you should consider machine locations and MRI safe practices. An MRI suite should be divided into four clearly marked zones to minimize potential risks and adverse incidents. The American College of Radiology (ACR) Guidance Document for Safe MR Practices: 2013 addresses numerous MR safety-related topics such as site access restrictions, MR siting considerations, and static magnetic field-related issues.

Safety Zone I – An unrestricted-access area where patients and healthcare personnel can access the MR environment.

Safety Zone II – A controlled-access area where, patients are greeted, but are supervised and unable to move around freely. Screening questions, patient histories, insurance, etc. are answered here. All materials that can be attracted by the magnets are removed from patients, visitors and staff before entering Zone III.

Safety Zone III – A restricted-access area. Under supervision, this area holds post-screen patients and acts as an MR control room. Zone III should utilize security methods, such as card access, to restrict all non-MR personnel. Magnetic fields are three-dimensional volumes that may project through floors, ceilings and roofs, necessitating clearly marked static magnetic fields strength. This is the last barrier to an incident or injury from the magnetic field, unscreened personnel, equipment, etc. before entering Zone IV.

Safety Zone IV is the MR scanning room itself. It should be clearly marked with a red light and lighted sign stating, “The Magnet is On”, as well as a warning sign on the floor that is usually placed in front of the door into the MR room. Everyone that enters Zone IV will pass through a ferro-metal detector before entering the MR room. The MR technicians should have direct visual observation to all access pathways into Zone VI.

Hutch MRI Tech Suite

5. MRI Rigging

After dusting off the old spec manual and locating the model number of the existing MRI, the question “How did we get it in here?” comes to mind. When the original MRI was rigged and installed, there was a pathway from the outside to the room. Now that several additions have been completed over the past 10 years, how do we get the existing MRI out and the new MRI in?

Rigging always poses a challenge as the weight of an MRI (around seven tons) can generate superstructure damage and easily crack a terrazzo floor. When removing a magnet, it is important to understand what is located below the current floor – slab on grade? basement? occupied floor? – the existing magnet dimensions (with and without the cover) and whether a tilt frame was originally used for transport. Last, if the hospital is selling the existing magnet, they should review the contracted rigger and their qualifications.

When it comes to rigging a new magnet in, the verification of all existing corridors, as well as handrail projections, ceiling cameras, and signage, need to be considered. The length of a long bore needs to be analyzed for turns, but most important is magnet height. Previously some magnets had tilt frames, which allowed them to slide under a normal 7’-0” door. Newer magnets are taller than existing magnets and may require the revision of existing door frame heights, which will come as added schedule time and project cost if not identified early on. These revisions may also need to occur off hours if the corridors are heavily used.

At Montefiore, the exterior storefront, and many 2-hour rated doors and frames along the 400-feet-long, rigging pathway needed to be modified to allow proper rigging of the magnet.

6. Redesign and Renovation

You may find that you need to renovate your MRI areas to comply with safety regulations or to accommodate your new machines. Or you may want to do a complete overhaul to give your facility a more modern look, like Montefiore Medical Center (Montefiore).

With outpatients and inpatients diagnosed in the new suite, Array assisted Montefiore in creating new prep/hold spaces with full sedation at each of the five bays. Supporting spaces include renovation to an adjacent ultrasound suite, patient bathrooms, locker rooms, storage and waiting areas. A full update of the four safety zones increased visibility and security for the three new magnets, their control rooms and the overall infrastructure.

7. Commissioning and Decommissioning

duPont MRI The magnet manufacturer should be contacted to conduct the decommissioning and ramping down of the existing magnet to prevent any helium quenching. After the magnet has been ramped down, a controlled removal of helium should occur.

The manufacturer will also provide proper commissioning of the new magnet, as well as the continuity of the radio frequency (RF) shield and electromagnetic shield. You may also consider contracting a third party commissioning agent for the RF and electromagnetic shields, as well as for the final room analysis after the magnet is installed, shimmed, and ramped up. This final analysis, as well as a grounding analysis, will help to prevent artifacts from showing up in the scans.

8. What to Do With the Old Machine

While the United States is very advanced in technology, many third-world countries do not possess adequate MRI technology. When thinking about scrapping or selling your existing MRI, consider that some medical institutions, like Montefiore, have more MRIs than other countries.

There is a large market, and substantial dollars, for used MRIs. The majority of sales involve the buyer paying for all rigging to remove the MRI. The buyer may even be the vendor supplying your new MRI, or someone from Craigslist.

Blog written by Jason Lee, former Principal and Studio Director with Array.