Guidelines for the Management of Patients with Vascular Access Ports Referred for MRI Examinations*

Frank G. Shellock, Ph.D., FACR, FISMRM
Adjunct Clinical Professor of Radiology and Medicine
Keck School of Medicine, University of Southern California
www.MRIsafety.com

In the clinical magnetic resonance imaging (MRI) setting, it is often necessary to manage patients with vascular access ports (1-6). MRI labeling information exists for numerous vascular access ports. By following the labeling information (i.e., presented in the Instructions for Use, Product Manual, Patient Identification Card, etc.), patients with vascular access ports have safely undergone MRI examinations, including those performed using MR systems operating at 3-Tesla (1-6). Notably, there has never been an adverse event reported in association with performing MRI exams in patients with these implants.

The standard policy that MRI labeling information is required before allowing the use of MRI in patients with vascular access ports limits access to this important diagnostic imaging modality for those patients for which labeling information is unavailable. Taking into account the peer-reviewed literature and other related information (1-6), it is acceptable to perform MRI examinations in patients with all vascular access ports by following specific guidelines developed by considering the primary safety concerns (i.e., magnetic field-related force, torque, and RF-induced heating) for these implants.

Guidelines. A patient with a vascular access port may undergo MRI using the following guidelines:

• 3-Tesla or less
   
• No restriction on the direction of the static magnetic field
   
• No restriction on the value of the spatial gradient magnetic field
   
• For a vascular access port located inside of the area of the transmitted RF energy, use a whole-body averaged specific absorption rate (SAR) of 2-W/kg (i.e., operating the MR system in the Normal Operating Mode)
   
• For a vascular access port located entirely outside of the area of the transmitted RF energy, a whole-body averaged specific absorption rate (SAR) of 4-W/kg (i.e., operating the MR system in the First Level Controlled Operating Mode) may be used
   
• Maximum imaging time, 15 minutes per pulse sequence, multiple sequences pulse are allowed
   

*Important Note: The “Guidelines for the Management of Patients with Vascular Access Ports Referred for MRI Examinations” should only be implemented for use after careful review by the supervising radiologist or other physician responsible for the MRI facility and with the adoption of the information as a written policy.

Important Note: Any deviation from the above MRI conditions requires prior approval by the supervising physician.

Important Note: These guidelines must be reviewed on an annual basis to confirm that no new vascular access port has become available that substantially deviates from the above MRI conditions or that is labeled, MR Unsafe.

References
(1) Shellock FG. Biomedical implants and devices: Assessment of magnetic field interactions with a 3.0-Tesla MR system. J Magn Reson Imaging 2002;16:721-732.

(2) Shellock FG, Nogueira M, Morisoli S. MR imaging and vascular access ports: Ex vivo evaluation of ferromagnetism, heating, and artifacts at 1.5-T. J Magn Reson Imaging 1995;4:481-484.

(3) Shellock FG, Shellock VJ. Vascular access ports and catheters tested for ferromagnetism, heating, and artifacts associated with MR imaging. Magnetic Resonance Imaging 1996;14:443-447.

(4) Titterington B, Shellock FG. Evaluation of MRI issues for an access port with a radiofrequency identification (RFID) tag. Magnetic Resonance Imaging 2013;31:1439-44.

(5) Shellock FG. Reference Manual for Magnetic Resonance Safety, Implants, and Devices: 2020 Edition. Biomedical Research Publishing Group, Los Angeles, CA, 2020.

(6) Shellock FG. Chapter 18, MRI Issues for Implants and Devices. In, MRI Bioeffects, Safety and Patient Management.  FG Shellock and JV Crues, Editors. Biomedical Research Publishing Group, Los Angeles, CA, 2022.

05/2025