Heating of hip joint implants in MRI: The combined effect of RF and switched‐gradient fields

Purpose To investigate how the simultaneous exposure to gradient and RF fields affects the temperature rise in patients with a metallic hip prosthesis during an MRI session. Methods In silico analysis was performed with an anatomically realistic human model with CoCrMo hip implant in 12 imaging posi...

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Vydané v:Magnetic resonance in medicine Ročník 85; číslo 6; s. 3447 - 3462
Hlavní autori: Arduino, Alessandro, Zanovello, Umberto, Hand, Jeff, Zilberti, Luca, Brühl, Rüdiger, Chiampi, Mario, Bottauscio, Oriano
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: United States Wiley Subscription Services, Inc 01.06.2021
John Wiley and Sons Inc
Predmet:
Absorption
Algorithms
Body temperature
Computer applications
Exposure
Full Papers—Computer Processing and Modeling
gradient coil heating
Heating
Hip
hip prosthesis
Magnetic resonance imaging
Medical imaging
MRI safety
numerical simulation
Precession
Prostheses
radiofrequency heating
Safety
Surgical implants
Transplants & implants
hip prosthesis
radiofrequency heating
MRI safety
gradient coil heating
numerical simulation
ISSN:0740-3194, 1522-2594, 1522-2594
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Popis
Shrnutí:Purpose To investigate how the simultaneous exposure to gradient and RF fields affects the temperature rise in patients with a metallic hip prosthesis during an MRI session. Methods In silico analysis was performed with an anatomically realistic human model with CoCrMo hip implant in 12 imaging positions. The analysis was performed at 1.5 T and 3 T, considering four clinical sequences: turbo spin‐echo, EPI, gradient‐echo, and true fast imaging sequence with steady precession. The exposure to gradient and RF fields was evaluated separately and superposed, by adopting an ad hoc computational algorithm. Temperature increase within the body, rather than specific absorption rate, was used as a safety metric. Results With the exception of gradient‐echo, all investigated sequences produced temperature increases higher than 1 K after 360 seconds, at least for one body position. In general, RF‐induced heating dominates the turbo spin‐echo sequence, whereas gradient‐induced heating prevails with EPI; the situation with fast imaging sequence with steady precession is more diversified. The RF effects are enhanced when the implant is within the RF coil, whereas the effects of gradient fields are maximized if the prosthesis is outside the imaging region. Cases for which temperature‐increase thresholds were exceeded were identified, together with the corresponding amount of tissue mass involved and the exposure time needed to reach these limits. Conclusion The analysis confirms that risky situations may occur when a patient carrying a hip implant undergoes an MRI exam and that, in some cases, the gradient field heating may be significant. In general, exclusion criteria only based on whole‐body specific absorption rate may not be sufficient to ensure patients’ safety.
Bibliografia:Funding information
17IND01 MIMAS Project and the EMPIR Program, co‐financed by the participating states and from the European Union’s Horizon 2020 Research and Innovation Program
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ISSN:0740-3194
1522-2594
1522-2594
DOI:10.1002/mrm.28666