A thorough screening process is used to assess all individuals entering the MRI environment
- Screening is a critical component of an MRI safety program and one of the most important responsibilities assumed by MRI technologists1.
- Performed correctly, screening is an effective method to identify potential hazards and reduce the likelihood of patient harm
- Most MRI safety incidents have been related to deficiencies in screening methods or properly restricting access to the MRI environment1
- All patients, family members and health facility employees must be screened before entering the MRI environment1,2 (see related guideline Authorized MRI personnel).
- A written screening form must be completed each time a patient (and/or an attending family member) undergoes an MRI scan, or enters the MRI environment1
- The screening form should be signed by the MRT and patient or substitute decision maker prior to entry into the MRI environment
- The importance of screening is carefully explained to the patient, who may forget to mention something, or neglect to mention an issue for fear of losing their appointment3
- MRI personnel are to be screened at initial employment and are subsequently responsible to self screen thereafter
- Screening procedures are carried out on three separate occasions1,3:
- A first screening is performed at the time the exam is ordered and is completed by the ordering physician in discussion with the patient
- A second screening is performed upon arrival and registration at the clinical MRI facility
- The third screening is performed by the MRT who reviews the MRI screening form completed by the patient upon arrival, and includes at least one verbal interview with the patient4
- If information gathered through screening is incomplete or in question, the technologist may1:
- Consult with the radiologist to obtain or clarify information
- Contact the referring physician to obtain or clarify information
- Refer to previous diagnostic imaging to identify potential concerns
- Look for surgical scars or other indications of the presence of implants.
- Obtain radiographic images of the areas in question
- If something is discovered through the screening process that contraindicates MRI, the MRT:
- Discusses the findings with the radiologist to determine the appropriate course of action to ensure continuity of care
- Explains the situation to the patient, answering any questions the patient has to the best of their ability (and within their scope of practice)
- Communicates the finding to the referring healthcare professional for consideration as per facility procedure
- Screening questions focus on issues that could pose a potential danger to the patient in the MRI environment.
- The screening process includes questioning about the presence of any metallic objects1.
- The patient is asked to list all prior surgical procedures
- Injuries to the body involving metallic foreign bodies are noted1,5
- Injuries involving penetrating metallic objects in the eye are identified, and followed up with an x-ray examination to establish the presence or absence of any remnants (also see Investigation of foreign bodies guideline)
- Patients are queried about the presence of medical implants or devices
- Confirm all implanted devices are identified by manufacturer and model via device card issued by medical facility at time of implantation or surgical report
- If the information is not available, the exam is postponed until the required documentation is obtained and cleared
- If the implant/device is not listed in the MRI Safety Reference Manual, the manufacturer is contacted directly to obtain the necessary safety information3
- The screening process identifies any past and present medical conditions that may affect the MRI procedure or the use of a contrast media, including1:
- Current or recently taken medications
- Known drug allergies
- Potential or confirmed pregnancy3
- Pre-existing psychiatric disorders, anxiety or claustrophobia
- History of renal impairment or hepatic insufficiency (nephrogenic systemic fibrosis (NSF) is associated with gadolinium use in such patients)3,6
- The IMRSER Magnetic Resonance (MR) Environment Screening Forms provides a template which can be adapted for local use4.
- There are scenarios where completing the screening process with the patient directly is impractical, or impossible:
- Underage patients
- Unconscious patients
- Patients with a language barrier
- In these scenarios, it is important that the MRT completes the screening process as per best practices described:
- This will require screening with someone who is the next most knowledgeable individual regarding the patient’s present condition and medical history
- For underage patients, the screening process is carried out with the parent or guardian for the child patient
- For unconscious patients, a caregiver, family member, or physician may be consulted
- If no reliable history can be otherwise obtained and if the requested MRI procedure cannot reasonably wait, patients are physically examined by Level 2 MRI Personnel*,6.
- Patients are examined for visible scarring or deformities that might be indicative of an implant (also see Investigation of foreign bodies guideline)
- X-rays or CT may be obtained (if not already available) to investigate the presence of metallic foreign objects in the skull/orbits, chest, abdomen, pelvis, or for areas that correspond to unidentified scarring
- For patients with a language barrier, measures are taken to secure the services of an interpreter in advance of the patient examination.
* Level 2 MRI personnel are defined as those with MRI safety education to ensure safety of all individuals and facility resources within the MRI environment
Shellock FG. Reference Manual for Magnetic Resonance Safety, Implants, and Devices. 2012 ed. Los Angeles, CA: Biomedical Research Publishing Group; 2012.
Westbrook C, Kaut Roth C, Talbot J. MRI in Practice. 3rd ed. London, UK: Blackwell Publishing Ltd; 2005.
Canadian Association of Radiologists. CAR Standard for Magnetic Resonance Imaging. Available from: http://www.car.ca/uploads/standards%20guidelines/20110428_en_standard_magnetic_resonance.pdf. [Accessed 21 Feb 2013]
Institute for Magnetic Resonance Safety, Education and Research. Guidelines for screening patients for MR procedures and individuals for the MR environment. Available from: http://www.imrser.org/PaperPDFRecord.asp?WebRecID=44&PgName=Guidelines&WebRecID=&sb_SummaryTitle=&. [Accessed 29 Jan 2018]
Seidenwurm DJ, et al. Cost utility analysis of radiographic screening for an orbital foreign body before MR imaging. Am J Neuroradiol 2000;21:426-433.
Kanal E, et al. American College of Radiology White Paper on MRI safety. AJR 2007;188:1-27.