Magnetic resonance imaging (MRI) is one of the non-invasive imaging techniques that have superior soft tissue contrasts and potential physiological and functional applications. As MRI does not expose the body to radiation, it has become a mainstay of non-invasive diagnostic radiology modality since the 1980s. MRI uses a very powerful magnetic field, rapidly changing magnetic fields, radio waves, and a computer to obtain detailed images. However, MRI is not without risks. As clinical demand for MRI has increased, healthcare professionals have to be trained in MRI safety to protect patients from the potential risks of MRI.
There are three major magnetic fields in an MRI scanner that have potential safety risks:
These magnetic fields in MRI scanners can cause five dangerous interactions in patients with metallic foreign bodies: projectile effect, twisting, burning, artifacts, and device malfunction (interference with a pacemaker). Therefore, all patients need to thoroughly be screened individually for foreign bodies before undergoing an MRI scan.
Radiologists, referring physicians and MR technologists, need to be able to assess MRI safety, patients' condition, and compatibility of medical devices to keep patients safe. There are different contraindications regarding MRI scanning:
A) Absolute contraindications:
It is important to know that some of these objects are unsafe, some are safe at 1.5 teslas only, and some are safe at 3 teslas MRI scanners. All devices and implants require investigation through a certified MRI safety website or the individual manufacturers' website. Any Referring physician, radiologist, or MR technologist must know how to find information about the compatibility of medical implants or devices in patients. It is for decades that medical materials, devices, and implants were made from non-ferromagnetic materials and are usually marked as MR safe or MR conditional. If there is no evidence or information about MRI safety of a device or implant, it has to be considered MRI unsafe.
B) Relative contraindications:
There are several relative contraindications:
Some other devices and implants might be contraindicated. To ensure patients' safety, the radiologist and MRI technologist must evaluate the type of device that patients have. Claustrophobic patients might refuse to complete the MRI scan and need sedation. These patients need to be well informed about the MRI scan procedure. The recommendation is that a physician has a discussion with them about the details in advance. Using Larger and opener MRI systems might be helpful in claustrophobic patients.
Gadolinium portion of the MRI:
MRI contrast agents are gadolinium chelates with different stability, viscosity, and osmolality. Gadolinium is a relatively very safe contrast; however, it rarely might cause allergic reactions in patients. Following patients need to be evaluated carefully before injection of gadolinium for MRI procedure:
Pregnancy and breastfeeding:
During pregnancy, MRI is a helpful imaging technique to evaluate obstetric and nonobstetric disorders during any trimester. To date, there is no known adverse effect or specific consequence for fetuses exposed to non-contrast MRI. However, the FDA determines gadolinium as a class C agent, and there is no established definitive evidence regarding MRI safety during pregnancy. Before MRI, a pregnant patient or who is suspected to be pregnant, the radiology team and physician should be informed. MRI only be taken during pregnancy to rule out suspected abnormalities and on a 1.5-tesla scanner.
The gadolinium contrast is excreted into breast milk in less than 0.04% of the dose injected to a mother. Also, of that tiny amount excreted into the milk, only 0.8% is absorbed by the baby. Thus, there should be no concern about continuing breastfeeding after MRI.
In recent years, diagnostic strategies increasingly use magnetic resonance imaging (MRI) to aid therapeutic plans. MRI helps in high-resolution investigations of soft tissues without the use of ionizing radiation. This safe modality currently becomes the imaging technique of choice for diagnosing musculoskeletal, neurologic, and cardiovascular disease. However, there are restrictions and contraindications caused by MRI magnetic fields, machine structure, and gadolinium contrast agents. Healthcare professionals need to be trained in magnetic resonance imaging safety to protect patients as well as other healthcare workers from the potential risks of MRI. It is essential to establish a close collaboration between the radiology team and physicians who provide care for the patient.
Due to potentially serious problems regarding safety issues with MRI, each patient needs to answer an MRI safety screening form before the scan. This screening is done during a verbal interview with the patient to ensure there is no contraindication for MRI. Patients need to be asked about any foreign substance that might interfere or with MRI acquisition. If a patient has devices or implants, the make and model of the object requires a check against relevant databases and MRI safety websites. Discussion with a radiologist or referring physician might be helpful to determine whether an MRI scan is the most suitable imaging modality or not. It is recommended that patients wear gowns in the MRI environment, To avoid metallic components of clothing. It is also recommended that the patient be informed about the details and the time of the procedure before the scan.
Although gadolinium chelates are generally well tolerated, MRI technologists and physicians need to be aware of adverse reactions to these contrast agents. MRI departments should provide appropriate medications and facilities to deal with possible reactions to contrast in patients. MRI scanner makes loud knocking noise during the procedure, which can cause damage to the hearing system. These noises could be attenuated by the patient using headphones and earplugs during the scan. During the MRI procedure, the personnel on hand must monitor the patient. With the help of an intercommunication system, the patient can speak with the MRI technologist or radiology nurse specialist, squeeze the communication ball, and also get commands.
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