Evaluation of MR issues for the latest standard brands of orthopedic metal implants: Plates and screws

Zou, Yue-Fen; Chu, Bin; Wang, Chuan-bing; Hu, Zhang

doi:10.1016/j.ejrad.2014.12.001

Cited by 31 publications

(20 citation statements)

References 19 publications

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“…In addition, we did not evaluate artifacts induced by the implants on the images, because neither spine nor body coils have been provided for 7 T systems. Furthermore, we did not examine other orthopedic implants and devices, which have been thoroughly investigated in fields of 3 T or less,4, 5, 6, 7, 8, 20, 21 because these materials were beyond the scope of this study. A previous study showed that certain orthopedic implants, such as femoral/hip joint implants, may involve possible risks 15.…”

Section: Discussionmentioning

confidence: 99%

“…Patients with spinal metallic implants may be examined using magnetic resonance imaging (MRI). The safety of spinal metallic implants and devices has been thoroughly investigated in MRI performed using magnetic fields of 3 T and less 2, 3, 4, 5, 6, 7, 8, 9. The implants, except for those made from highly ferromagnetic materials, exhibited minimal attraction, and heating by static magnetic fields and radiofrequency (RF) radiation, respectively.…”

mentioning

confidence: 99%

“…The safety of spinal metallic implants and devices has been thoroughly investigated in MRI performed using magnetic fields of 3 T and less. [2][3][4][5][6][7][8][9] The implants, except for those made from highly ferromagnetic materials, exhibited minimal attraction, and heating by static magnetic fields and radiofrequency (RF) radiation, respectively. In accordance with these results, almost all spinal implants and devices are considered safe or conditionally acceptable in MRI examinations.…”

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confidence: 99%

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Assessment of magnetic field interactions and radiofrequency-radiation-induced heating of metallic spinal implants in 7 T field

et al. 2017

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The safety of metallic spinal implants in magnetic resonance imaging (MRI) performed using ultrahigh fields has not been established. Hence, we examined whether the displacement forces caused by a static magnetic field and the heating induced by radiofrequency radiation are substantial for spinal implants in a 7 T field. We investigated spinal rods of various lengths and materials, a screw, and a cross‐linking bridge in accordance with the American Society for Testing and Materials guidelines. The displacement forces of the metallic implants in static 7 T and 3 T static magnetic fields were measured and compared. The temperature changes of the implants during 15‐min‐long fast spin‐echo and balanced gradient‐echo image acquisition sequences were measured in the 7 T field. The deflection angles of the metallic spinal materials in the 7 T field were 5.0–21.0° [median: 6.7°], significantly larger than those in the 3 T field (1.0–6.3° [2.2°]). Among the metallic rods, the cobalt–chrome rods had significantly larger deflection angles (17.8–21.0° [19.8°]) than the pure titanium and titanium alloy rods (5.0–7.7° [6.2°]). The temperature changes of the implants, including the cross‐linked rods, were 0.7–1.0°C [0.8°C] and 0.6–1.0°C [0.7°C] during the fast spin‐echo and balanced gradient‐echo sequences, respectively; these changes were slightly larger than those of the controls (0.4–1.1°C [0.5°C] and 0.3–0.9°C [0.6°C], respectively). All of the metallic spinal implants exhibited small displacement forces and minimal heating, indicating that MRI examinations using 7 T fields may be performed safely on patients with these implants. © 2016 The Authors. Journal of Orthopaedic Research Published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 35:1831–1837, 2017.

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Section: Discussionmentioning

confidence: 99%

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Assessment of magnetic field interactions and radiofrequency-radiation-induced heating of metallic spinal implants in 7 T field

et al. 2017

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“…During the MRI scan, the strong RF electromagnetic field interacts with the metallic implant, causing local heating near the implant. To date, both numerical and experimental investigations have been conducted to study the RF‐induced heating of various individual orthopedic implants . However, patients with severe bone fractures often need more than 1 implant, as shown in Figure .…”

Section: Introductionmentioning

confidence: 99%

Computational and experimental investigation of RF‐induced heating for multiple orthopedic implants

Guo

Zheng

Wang

et al. 2019

Magnetic Resonance in Med

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Purpose: This paper investigates the RF-induced heating for multiple adjacent orthopedic implants under MRI at 1.5T and 3T exposure. When multiple implants are closely spaced to each other, the interactions between the implants may affect the RF-induced heating. Traditional RF-induced heating labeling is often only applicable to configurations of an individual implant, and is not applicable for multi-implant configurations. Therefore, the aim of this study is to evaluate the effects of multiple orthopedic implants on RF-induced heating and to propose potential appropriate instructions for safe scanning of multi-implantable orthopedic implants. Methods: Typical plate and nail implants were used as examples. The effects of implant configuration, relative positions, and number of implants were investigated.Numerical simulations were conducted using full-wave electromagnetic simulation software. Experimental measurements at 1.5 T were performed to validate the numerical results. Results: Numerical results indicate that, due to device interaction, the RF-induced heating of multiple medical implants can be significantly different from that of a single implant. The measured temperature rise for multiple devices could be 2.7 times larger than that of a single implant. Conclusion: Our results confirm that RF-induced heating of multiple implants can be quite different, and do not follow simple superposition of the results from single devices. Instructions for safe scanning of individual orthopedic devices would not be applicable to multi-implant configurations. K E Y W O R D Sfinite-difference time domain, magnetic resonance imaging, multiple orthopedic implants, radiofrequency heating

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“…Metallic implants such as prostheses, pacemakers, dental implants, and surgical clips are known sources of MR artifacts (6). The ferromagnetic material disturbs the local magnetic field homogeneity, potentially resulting in signal voids in the MR image.…”

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confidence: 99%

The Effect of Susceptibility Artifacts Related to Metallic Implants on Adjacent-Lesion Assessment in Simultaneous TOF PET/MR

Svirydenka

Delso²,

Barbosa

et al. 2017

J Nucl Med

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Metalic implants may affect attenuation correction (AC) in PET/MR imaging. The purpose of this study was to evaluate the effect of susceptibility artifacts related to metallic implants on adjacent metabolically active lesions in clinical simultaneous PET/MR scanning for both time-of-flight (TOF) and non-TOF reconstructed PET images. Methods: We included 27 patients without implants but with confirmed 18 F-FDG-avid lesions adjacent to common implant locations. In all patients, a clinically indicated whole-body 18 F-FDG PET/MR scan was acquired. Baseline non-TOF and TOF PET images were reconstructed. Reconstruction was repeated after the introduction of artificial signal voids in the AC map to simulate metallic implants in standard anatomic areas. All reconstructed images were qualitatively and quantitatively assessed and compared with the baseline images. Results: In total, 51 lesions were assessed. In 40 and 50 of these cases (non-TOF and TOF, respectively), the detectability of the lesions did not change; in 9 and 1 cases, the detectability changed; and in 2 non-TOF cases, the lesions were no longer visible after the introduction of metallic artifacts. The inclusion of TOF information significantly reduced artifacts due to simulated implants in the femoral head, sternum, and spine (P 5 0.01, 0.01, and 0.03, respectively). It also improved image quality in these locations (P 5 0.02, 0.01, and 0.01, respectively). The mean percentage error was 23.5% for TOF and 24.8% for non-TOF reconstructions, meaning that the inclusion of TOF information reduced the percentage error in SUV max by 28.5% (P , 0.01). Conclusion: Qualitatively, there was a significant reduction of artifacts in the femoral head, sternum, and spine. There was also a significant qualitative improvement in image quality in these locations. Furthermore, our study indicated that simulated susceptibility artifacts related to metallic implants have a significant effect on small, moderately 18 F-FDG-avid lesions near the implant site that possibly may go unnoticed without TOF information. On larger, highly 18 F-FDGavid lesions, the metallic implants had only a limited effect. The largest significant quantitative difference was found in artifacts of the sternum. There was only a weak inverse correlation between lesions affected by artifacts and distance from the implant.

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Evaluation of MR issues for the latest standard brands of orthopedic metal implants: Plates and screws

Cited by 31 publications

References 19 publications

Assessment of magnetic field interactions and radiofrequency-radiation-induced heating of metallic spinal implants in 7 T field

Assessment of magnetic field interactions and radiofrequency-radiation-induced heating of metallic spinal implants in 7 T field

Computational and experimental investigation of RF‐induced heating for multiple orthopedic implants

The Effect of Susceptibility Artifacts Related to Metallic Implants on Adjacent-Lesion Assessment in Simultaneous TOF PET/MR

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