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MRI of pregnant patients (MRI specific)

 

MRI in pregnant patients is appropriate when the benefits outweigh the risks

 

+ Risks of MRI for the pregnant patient

  • Patients in the first trimester of pregnancy might be more susceptible to potential adverse effects including:1,2
    • Possible bioeffects of the static magnetic field
    • Risks associated with exposure to gradient magnetic fields
    • Potential adverse effects of radiofrequency (RF) energy
    • Possible adverse effects related to the combination of all three magnetic fields

 

  • In order to properly assess risk with regard to pregnancy, it is recommended that every female patient of childbearing age (between 11-55 years) is asked before a procedure if there is a possibility that she is pregnant.3,4

+ Appropriate use of MRI in pregnant women

  • MRI may be used in pregnant women if other non-ionizing forms of diagnostic imaging are inadequate or if the examination provides important information that would otherwise require exposure to ionizing radiation.1,5
  • Before proceeding with MRI, the healthcare team considers the following questions:1
    • Would sonography be satisfactory for diagnosis?
    • Is the MR procedure appropriate to address the clinical question?
    • Is early delivery a consideration?
    • Is termination of the pregnancy a possibility?

 

  • MRI should not be withheld when the benefits of the examination clearly outweigh the risks, such as in the following cases:1
    • Brain and spine symptoms requiring imaging
    • Cancer requiring imaging
    • Chest, abdominal and pelvic signs and symptoms of active disease where sonography results are inconclusive
    • Specific, suspected cases of fetal anomaly or complex fetal disorder

+ Obtaining informed consent

  • Informed consent is obtained by the radiologist, prior to initiating the exam.
    • A consent form is signed by both the patient and the radiologist

+ MRI with contrast

  • Gadolinium enhancement is best avoided when examining the pregnant patient.2
    • Research on the risks posed by gadolinum-based contrast for pregnant mothers is limited, and there is insufficient evidence to conclude that it poses no risk to the fetus1

 

  • If it is absolutely necessary to proceed using a contrast agent, a consent form is signed by the patient following an informed consent process which includes an explanation of the potential risks and benefits by the radiologist.

+ Counseling

  • Pregnant patients are informed that current data shows MRI to be relatively safe for pregnant women with no evidence of deleterious effects in the literature.1
  • If the patient is to undergo a procedure requiring gadolinium-based contrast, an explanation is provided regarding the risks of contrast media and the precautions that are being undertaken to avoid unnecessary exposure to risk.

+ References

  1. Shellock FG. Reference Manual for Magnetic Resonance Safety, Implants, and Devices. 2012 Ed. Los Angeles, CA: Biomedical Research Publishing Group; 2012.
  2. Westbrook C, Kaut Roth C, Talbot J. MRI in Practice. 3rd Ed. London, UK: Blackwell Publishing Ltd.; 2005.
  3. Martensen, Kathy. Radiographic Image Analysis. St Louis, 2011, Saunders Elesvier.
  4. Health Canada. Safety Code 35: Safety Procedures for the Installation, Use and Control of X-ray Equipment in Large Medical Radiological Facilities. Available at: http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/safety-code_35-securite/index-eng.php. Accessed April 30, 2013.
  5. Kanal E, et al. American College of Radiology White Paper on MRI safety. AJR 2007;188:1–27.

Related guidelines

>Contrast media issues

 

Validation

May 8, 2013

 

 
Canadian Association of Medical Radiation Technologists
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phone: 613 234-0012 / 800 463-9729
fax: 613 234-1097
www.camrt.ca