The magnetic fields generated from an MRI to capture diagnostic images are extremely powerful. As such, there are numerous safety protocols that must be followed during operation. The MRI safety protocols created by the ACR Guidance Document on MR Safe Practices: 2013 are designed to ensure the safety of the patients as well as the staff.
The 2017 Study: The Prevalence of Unanticipated Events Associated with MRI Examinations: A Benchmark for MRI Quality, Safety, and Patient Experience
This 2017 study evaluated how widespread unanticipated events were when it came to MRI exams. Reports evaluated for this study were linked to 17 MRI scanners. These scanners are located in the radiology department of a community- and university-associated, single health care system.
The unanticipated event information was attained via incident reports that were filed by various MRI personnel at these locations. Nearly 35,000 scans, which were taken from June 2013 through November 2014, were evaluated in this study. According to the study authors, some type of unanticipated event occurred in nearly 20 percent of all the MRI scans that were performed during this time frame.
Categorization and Rates of Unanticipated Events
Of the 34,587 examinations that were assessed, 58 percent occurred when the MRI was performed as an outpatient procedure in a community-affiliated single health system and 87 percent occurred when it was performed in a university-affiliated one, with nearly 2 percent of the patients being included in multiple category events. Below is the overall breakdown of the results attained during this study.
Unanticipated event rates, categorized:
- Foreign bodies — 0.5 percent
- Patient events related to contrast material — 1.3 percent
- Technical problems — 1.5 percent
- Scheduling and orders — 1.9 percent
- Scan delays — 3.3 percent
- Patient events that were not related to contrast material — 10.4 percent
A breakdown of the 10.4 percent of patient events that were not related to contrast material:
- Improper study protocol — 5.1 percent
- Lack of IV access — 6.7 percent
- Patient has difficulty holding his/her breath — 7.9 percent
- A delay in the radiology department — 8.6 percent
- Patient requires general anesthesia/sedation — 11.9 percent
- Patient feels uncomfortable — 13.9 percent
- The patient is claustrophobic — 31.3 percent
- The patient moves as the images are being taken — 53.1 percent
Although some of these categories do not seem to qualify as ‘safety issues,’ keep in mind that each of these issues can lead to a delay: Once MRI personnel fall behind, time pressures may consequently lead to other events that are safety concerns.
Safety Precautions of MRI Operation
Since an MRI does not produce radiation, this procedure is usually regarded as a safer option when compared to the other diagnostic imaging systems available; however, there are still a few possible risks associated with MRIs.
Potential Problems Related to MRI Operation
- Magnetic attraction — many of the closed MRI systems have magnets that are producing magnetic fields nearly 21,000 times greater than the Earth’s natural pulse electromagnetic fields (ENPEMF). This field is extremely strong has the ability to pull metal objects through the air to the system, including oxygen tanks and wheelchairs.
- Magnet quench — this term refers to the complete shutdown of the MRI’s magnetic field. This shutdown can be purposeful or by accident; however, once the coils lose absolute zero temperature, the become resistive, which allows the helium to escape. As the helium is released, it turns from a liquid to a gas. If this helium is not ventilated from the room, it displaces the oxygen, which can lead to asphyxia (suffocation).
- Electronic disturbances — magnetic fields can cause disturbances to everyday items like cell phones, cameras and analog watches, which can be a hassle; however, these fields can also cause pacemakers and hearing aids to malfunction.
- Hearing issues — MRIs are loud; therefore, some patients may experience hearing issues after their scan, especially if they do not wear ear plugs.
- Thermal burns — these burns are caused by the MRIs radio-frequency (RF) field generating currents in wires that are either on or near the patient. In addition, prolonged imaging can cause the patient’s core body temperature to rise.
Adhering to the safety precautions set forth by the ACR Guidance Document on MR Safe Practices: 2013, can help facilities improve their MRI safety practices.
Safety Precautions MRI Personnel Need to Follow
Staff members need to take every precaution possible to ensure patients and employees remain safe around the MRI equipment.
Prior to an MRI, each patient must be properly prepared to ensure he/she does not sustain burns during the procedure: This is true even for patients who do not have any kind of implant.
According to The Guidelines to Prevent Excessive Heating and Burns Associated with MRI Procedures, proper patient preparation includes:
- Removing all metal objects that have contact with the patient’s skin — these objects include drug delivery patches that have metallic components, jewelry, belts, eyeglasses, hairpins and barrettes, etc.
- Restricting access to the MRI room — by only allowing equipment, devices, materials and accessories (e.g., electrodes, ECG leads, etc.) that have been tested and deemed safe to be in the room.
- Using insulation material that is at least 1 cm thick — to prevent the patient from having skin-to-skin contact during the MRI. In addition, this material can keep the formation of closed-loops from touching the patient’s body parts.
Implement these rules for patients, staff members operating MRI systems as well as for anyone else who will enter the MRI rooms:
- Wear clothing that is considered MRI-compatible — some clothing contains metallic microfiber. These microfibers can contribute to thermal burns. For this reason, providing patients with scrub tops and bottoms prior to their scan is recommended.
- Pockets must be emptied — before entering the MRI room, staff and patients must remove everything from their pockets. These items include keys, smartphones, coins and pens, etc. If the metal items are not removed, they may become dangerous projectiles and the electronic devices could malfunction.
- Makeup and tattoos — besides concerns related to metal implants, patients who have tattoos or makeup may experience discomfort because some makeup and tattoo inks contain iron. Staff members need to ask patients if they have any tattoos and request that they remove their makeup before their MRI scan. The patient should be instructed to inform the technician if any discomfort is being experienced in the areas that are tattooed during the scan.
- Noise protection — patients should be given ear plugs to help reduce the loud noises produced by the MRI system as it scans. Providing ear plugs reduces the patient’s risk of developing a hearing problem.
Staff Safety Tips:
- Only level II staff members should be able to access the MRI room — these employees should have the knowledge and training necessary to safely operate the MRI system while keeping safety in mind. Level II staff includes: MRI nurses, MRI technologists and radiologists. Level I staff includes: ICU nurses, physician’s assistants, public safety personnel and floor nurses. Level I staff members should not be permitted to enter the MRI room unless a level II staff member is closely monitoring them.
- Minimize the number of staff members in the MRI room at one time — by reducing the number of people in the MRI room, the likelihood of a mishap decreases because otherwise confusion over who is doing what could lead to mistakes.
- Certain items must not be kept in the MRI room — monitors, stretchers, wheelchairs, oxygen tanks and IV pumps should not be kept in the MRI room; however, there are MRI-compatible versions of this equipment available. This special type of equipment should always be available in the MRI room.
- Close the door to the MRI room — unless entering or exiting the room, the door needs to remain closed. By keeping the door closed during imaging, the RF noise is reduced; thus, ensuring the magnetic field will not disturb anything that is outside of the MRI room.
- Keep the MRI clean — after each scan, the equipment must be returned to its original location. Phantoms and coils must never be set on the floor.
- Inspect the MRI system before each scan — staff should make sure that none of the surface or body flex coils are unplugged. If they are, scans should not be performed with that system until it has been evaluated and deemed safe, and fully operational.
- Memorize emergency procedures — each staff member needs to learn what the codes at the facility specify; otherwise, when an emergency arises, the staff member will be at a loss.
- Patients should never be left unattended — when patients are being scanned, they should never be left alone. When the staff member who is in charge must leave the room, another qualified staff member must be asked to oversee the patient until the staff member in charge returns.
- All the equipment used must receive pre-approval — none of the supplies, research equipment or coils should be used without the approval of an MRI safety official or committee.
Recognize and Follow the 4 MRI Environment Safety Zones
The MRI environment should be divided into four different zones:
- Zone 1: The outside — outside the building is safe for all staff and the general public. Although the MRI will generate some minimal magnetic fringe fields outside, they are weak and harmless.
- Zone 2: Reception/Waiting area — this area leads to the control room. Although it is a safe area for the public and for staff, it needs to be supervised to keep unscreened and unauthorized individuals from entering the third zone.
- Zone 3: Area close to the MRI room — the MRI’s magnetic field will be strong in this zone, which is why no one should enter this zone without being fully screened and changed into MRI-appropriate clothing. The control room and computer are located in this zone.
- Zone 4: The MRI room — this room is where the magnetic field is the most powerful. A level II staff member should always be present. To eliminate the risks associated with a serious injury, all objects with a high susceptibility to magnetization must be kept out of this room.