Cardiovascular implantable electronic devices: a review of the dangers and difficulties in MR scanning and attempts to improve safety

Insights into Imaging, Jun 2017

Pei Ghim Poh, Charlene Liew, Colin Yeo, Le Roy Chong, Andrew Tan, Angeline Poh

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Cardiovascular implantable electronic devices: a review of the dangers and difficulties in MR scanning and attempts to improve safety

Insights Imaging Cardiovascular implantable electronic devices: a review of the dangers and difficulties in MR scanning and attempts to improve safety Pei Ghim Poh 1 3 5 6 7 8 Charlene Liew 1 3 5 6 7 8 Colin Yeo 0 1 3 5 6 7 8 Le Roy Chong 1 3 5 6 7 8 Andrew Tan 1 3 5 6 7 8 Angeline Poh 1 3 5 6 7 8 0 , Singapore 529889 , Singapore 1 Le Roy Chong 2 17-10 Tower 5 , Singapore 150167 , Singapore 3 Charlene Liew 4 Pei Ghim Poh 5 Department of Cardiology, Changi General Hospital , 2 Simei Street 6 Singhealth Radiology Residency , 167 Jalan Bukit Merah 7 Department of Radiology, Changi General Hospital , 2 Simei Street 3 , Singapore 529889 , Singapore 8 Angeline Poh An increasing number of patients are being treated with cardiovascular implantable electronic devices (CIEDs), many of which are MR conditional. There is a lack of literature on the safe scanning of MR conditional CIEDs. This review article discusses MR imaging safety in patients with implanted CIEDs. Guidelines on safe use and indications of imaging patients with MR conditional CIEDs are described, followed by a pictorial essay of the radiographic features of these devices. We also discuss the challenges of monitoring the patient in the MR environment, advances in MRI conditional imaging of devices, availability, limitations and workflow including vendorspecific and other collaborative efforts to simplify the scanning process. Radiologists must be able to facilitate the safe utilization of MR imaging in patients who have CIEDs. A thorough knowledge of the hazards of imaging non-MR compatible devices is required as well as knowing how to correctly identify and manage the imaging of patients with MR conditional CIEDs. Finally, we propose steps required to facilitate the safe scanning of patients with MR conditional CIEDs adopted in our institution and a contingency plan in the event that an inadvertent MR scan of a patient with a MRI unsafe CIED should occur. Equipment safety; Equipment design; Magnetic resonance imaging; Pacemaker; Artificial; Physics - Main Messages Risks of MR imaging in patients who have CIEDs have been worked around. There are many technical limitations in enabling safe MR scanning of CIEDs. Radiological identification of MRI-conditional status of CIEDs is useful. Standardizing conditions for safe MRI scanning is important. We offer example algorithms for facilitating safe MRI scanning of CIEDs. Introduction Magnetic resonance imaging (MRI) has steadily increased in use worldwide [ 1 ]. We believe that there is a foreseeable increase in the number of patients with cardiovascular implantable electronic devices (CIEDs) who will require a MRI. An estimated 75% of patients with CIEDs will have an indication requiring MRI during their lifetime [ 2 ]. This review article discusses the safe use of MRI in patients who have implanted CIEDs. Radiologists should have a basic grasp of the principles behind the re-design and engineering of these devices, once considered to be an absolute contraindication to scanning. The known hazards of MRI unsafe CIEDs are described, followed by guidelines on safe use, indications and limitations of imaging patients with MR conditional CIEDs, including a brief pictorial essay of the radiographic features of these devices. Finally, we also offer steps to facilitate the safe scanning of patients with MR conditional CIEDs in the form of a proposed guideline, which was adopted in our institution, and a contingency plan if an inadvertent MR scan of a patient with a MRI unsafe CIED should occur. These have been ratified by the authors’ institutional medical board review process and have been implemented successfully at the time of writing. What are MRI safe devices? Implants, devices or materials should routinely undergo evaluation prior to a MRI procedure if known, and are categorized as safe, conditional or unsafe [ 3 ]. Safe devices are safe within the MR environment. The object is usually made from non-ferromagnetic components. There are no MR safe cardiovascular implantable devices at the time of writing. Conditional devices are safe for the patient undergoing MRI only if specific conditions are met. This is usually often due to the presence of a weakly ferromagnetic component in the implantable device. Current recommendations support safe scanning at 1.5 T although several studies with scanning at 3 T exists. Unsafe devices pose potential risk(s) to an individual in the MR environment, for which the physical concepts are discussed below. Hazards of imaging MRI unsafe cardiovascular devices A cardiac pacemaker system is composed of leads and a pulse generator. Within the pulse generator are connectors, circuitry and a battery which may be ferromagnetic. This results in interactions with the magnetic field or RF pulse in MR environments [ 1, 2 ]. Magnetic field interactions include torque effect, induced electrical currents and reed/Hall sensor switch activation. RF pulse effec (...truncated)


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Pei Ghim Poh, Charlene Liew, Colin Yeo, Le Roy Chong, Andrew Tan, Angeline Poh. Cardiovascular implantable electronic devices: a review of the dangers and difficulties in MR scanning and attempts to improve safety, Insights into Imaging, 2017, pp. 405-418, Volume 8, Issue 4, DOI: 10.1007/s13244-017-0556-3