MRI Safety Concerns: Anatomy Impacts on Radiofrequency Induced Heating and Implant Impacts on Gradient Induced Peripheral Nerve Stimulation

Magnetic Resonance Imaging (MRI) is a very useful technology but there are some safety concerns for patients. Radiofrequency (RF) induced heating and gradient induced peripheral nerve stimulation (PNS) are two typical safety concerns. Although many literatures have found the importance of them, they are not fully investigated. In this dissertation, the impact of anatomy on the RF-induced heating and the impact of orthopedic implants on the gradient-induced PNS are investigated. The influence of minor postures and body-loop postures on the RF-induced heating for the patients without implants and patients with Active Implanted Medical Devices (AIMD) are presented. For the patients with passive implants, the posture impacts are studied, and a new phantom is proposed to evaluate the RF-induced heating more accurately compared with the standard American Society for Testing and Materials (ASTM) phantom. Based on the results and conclusions, a lot of guidance and suggestions are provided to ensure patient’s RF safety and improve the assessment of medical devices. A preliminary study for impacts of orthopedic implants on the gradient induced PNS is conducted. It is found that the presence of orthopedic implants can significantly change the electric field distribution, thus influencing the PNS threshold. Implant effects are suggested to be considered when evaluating PNS constraint for high gradient MR system.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Electrical Engineering

Grantor

University of Houston

Year dc:date.issued

2024

Author dc:creator

• Yang, Xiaolin

Advisor dc:contributor.advisor

• Chen, Ji

Committee members dc:contributor.committeemember

• Jackson, David R.
• Zheng, Jianfeng
• Benhaddou, Driss
• Shrivastava, Devashish

• MRI safety, Implants, Radiofrequency, Gradient

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10657/17678

OAI identifier oai:identifier

oai:uh-ir.tdl.org:10657/17678