MR safety assessment of active implantable medical devices

Aissani, S.; Laistler, Elmar; Felblinger, Jacques

doi:10.1007/s00117-019-0541-6

Cited by 6 publications

(4 citation statements)

References 22 publications

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“…The average speci c energy absorption rate (SAR) during the scan can be estimated by dividing the time-average input RF power by the sample mass [13]. Therefore, the experimental average SAR is well below the guideline value [14]. We demonstrate that the transnasal coil is unlikely to cause thermal damage to the patient and is safe to be used in the clinical environment.…”

Section: Discussionmentioning

confidence: 88%

Flexible In-Cavity MRI Receiving Coil for Ultrahigh Resolution Imaging of the Pituitary Gland

Liu

Patel

Peeters

et al. 2023

Preprint

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Purpose Preclinical design and construction of a flexible intra-sphenoid coil aiming for submillimeter resolution of the human pituitary gland.Methods Sphenoid sinus measurements determined coil design constraints for use in > 95% of adult patients. Temperature safety parameters were tested. The prototype 2-cm diameter coil was positioned in the sphenoid sinus of cadaveric human heads utilizing the transnasal endoscopic technique that is used clinically. Signal-to-noise ratio (SNR) was estimated comparing the prototype transnasal coil versus a standard clinical head coil. One cadaver pituitary gland was explanted and histologically examined for correlation to the imaging findings.Results With the coil positioned directly atop the sella turcica at 00 angle of the B0 static field, the craniocaudal distance (24 ± 4 mm) was the limiting constraint. Phantom experiments showed a negligible change in temperature at two sites over 15 minutes. The flexible coil was placed transnasally in cadaveric specimens using an endoscopic approach. The image quality was subjectively superior at higher spatial resolutions relative to the commercial 20-channel head coil. An average 17-fold increase in SNR was achieved within the pituitary gland. Subtle findings visualized only with the transnasal coil had potential pathological correlation with immunohistochemical analysis.Conclusions A transnasal radiofrequency coil feasibly provides a 17-fold boost in SNR at 3T, providing, in principle, equivalent imaging to a 51T scanner using a standard head coil. The ability to safely improve the quality of pituitary imaging may be helpful in the identification and subsequent surgical resection of small functional pituitary lesions.

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Section: Discussionmentioning

confidence: 88%

Flexible In-Cavity MRI Receiving Coil for Ultrahigh Resolution Imaging of the Pituitary Gland

Liu

Patel

Peeters

et al. 2023

Preprint

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“…To our knowledge, this is the first report demonstrating viability of repeated daily MR imaging sessions at 0.35 T with off-label scanning of a cochlear implant. Compared with prior studies 2 , 5 that demonstrated feasibility on diagnostic MR scanners with cochlear implants, patients treated with MRgRT are potentially at higher risk because of the requirement to undergo multiple MRI scans at the time of simulation as well as before each treatment day. As such, minimizing the number of fractions is particularly advantageous.…”

Section: Discussionmentioning

confidence: 99%

“…The MR clearance workflow ( Fig. 3 ) is designed to clear each implant and proceed with imaging/treatment based on known/unknown origin, passive/active nature of the implant, 5 and vendor on/off-label usage instructions. We implemented this specific protocol as a foundational safety component of our MRgRT program.…”

Section: Methodsmentioning

confidence: 99%

The First Report of Using Low-Field MRI-Guided Radiation Therapy in a Patient With a Cochlear Implant

Ziegler,

McCulloch,

Bassiri

et al. 2024

Advances in Radiation Oncology

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“…They can concentrate the RF power, potentially causing high-power depositions in the vicinity of these objects. Severe MRI-related RF heating of electrically conducting structures and associated risks have been shown for interventional guide wires [12], implanted electrodes for deep brain stimulators [13] and cardiac pacemaker leads [14].…”

Section: Introductionmentioning

confidence: 99%

Direct Temperature Measurements of Cardiac Stent during MRI Examinations

Acri,

Campanella,

Vermiglio

et al. 2023

Applied Sciences

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Nowadays, Magnetic Resonance Imaging (MRI) is considered the gold standard for imaging the brain, spinal cord, musculoskeletal system, head and neck, and complex congenital heart malformations; consequentially, the number of MRI scans in patients with implantable electronic devices has simultaneously increased. During the entire length of the MRI exam, patients are exposed to electromagnetic fields with different characteristics (static, low frequency, radiofrequency fields), which are related to different risks. The scarce available literature about MRI-induced heating on cardiac stents suggests that excessive temperature rise occurs only in unfavorable cases. Ideally, RF safety assessment could be performed during the anamnestic process, but this simulation process’s results are too slow to be performed before patient MRI examination. In this context, we developed a dedicated measurement set-up by focusing our target on the measurement of the heating of a cardiac stent during an MRI examination. Results for the temperature rise trend along the entire stent length during a clinical MRI protocol are shown together with the local Specific Absorption Rate (SAR) values and cumulative equivalent minutes at 43 °C (CEM43°C), in order to ensure the safety of patients with MR-conditional devices, also with a view to not inappropriately preclude their access to MRI scans. The obtained results show that the maximum temperature rise (4.12 °C) is within the limit of 5 °C stated in the stent manual for 15 min of continued scanning with the specific conditions. The maximum temperature rise was in correspondence with the stent tips and calculated SAR confirms the fact that two hotspots are present near the tips of the stent. Finally, the calculated CEM43°C remained well below the proposed threshold for muscle tissue.

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MR safety assessment of active implantable medical devices

Cited by 6 publications

References 22 publications

Flexible In-Cavity MRI Receiving Coil for Ultrahigh Resolution Imaging of the Pituitary Gland

Flexible In-Cavity MRI Receiving Coil for Ultrahigh Resolution Imaging of the Pituitary Gland

The First Report of Using Low-Field MRI-Guided Radiation Therapy in a Patient With a Cochlear Implant

Direct Temperature Measurements of Cardiac Stent during MRI Examinations

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