{"id":{"repo_id":"houston","oai_identifier":"oai:uh-ir.tdl.org:10657/17678"},"canonical_url":"https://search.dev.ndltd.org/etd/houston/oai:uh-ir.tdl.org:10657/17678","repository":{"repo_id":"houston","name":"University of Houston","base_url":"https://uh-ir.tdl.org/server/oai/request"},"display":{"title":"MRI Safety Concerns: Anatomy Impacts on Radiofrequency Induced Heating and Implant Impacts on Gradient Induced Peripheral Nerve Stimulation","abstract":"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.","abstract_html":"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.","abstract_has_math":false,"creators":["Yang, Xiaolin"],"institution":"University of Houston","degree_name":"Doctor of Philosophy","degree_level":"Doctoral","degree_discipline":"Electrical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Chen, Ji"],"committee_chairs":[],"committee_members":["Jackson, David R.","Zheng, Jianfeng","Benhaddou, Driss","Shrivastava, Devashish"],"year":2024,"date_issued":"2024-05-07","date_published":"2024-05-07","updated_at":"2026-07-24T02:32:34Z","subjects":["MRI safety, Implants, Radiofrequency, Gradient"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/10657/17678","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Chen, Ji"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Jackson, David R.","Zheng, Jianfeng","Benhaddou, Driss","Shrivastava, Devashish"]},{"key":"dc:creator","label":"Author","values":["Yang, Xiaolin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2024-07-26T04:02:58Z"]},{"key":"dc:date.issued","label":"Date","values":["2024-05-07"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Houston"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["MRI safety, Implants, Radiofrequency, Gradient"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/10657/17678"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["MRI Safety Concerns: Anatomy Impacts on Radiofrequency Induced Heating and Implant Impacts on Gradient Induced Peripheral Nerve Stimulation"]}]}],"canonical_facts":{"dc:contributor.advisor":["Chen, Ji"],"dc:contributor.committeemember":["Jackson, David R.","Zheng, Jianfeng","Benhaddou, Driss","Shrivastava, Devashish"],"dc:creator":["Yang, Xiaolin"],"dc:date.accessioned":["2024-07-26T04:02:58Z"],"dc:date.issued":["2024-05-07"],"dc:description.abstract":["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."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/10657/17678"],"dc:language.iso":["en"],"dc:subject":["MRI safety, Implants, Radiofrequency, Gradient"],"dc:title":["MRI Safety Concerns: Anatomy Impacts on Radiofrequency Induced Heating and Implant Impacts on Gradient Induced Peripheral Nerve Stimulation"],"dc:type":["Thesis"],"thesis:degree_discipline":["Electrical Engineering"],"thesis:degree_level":["Doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["University of Houston"]},"updated_at":"2026-07-24T02:32:34Z"}