Quantative MR-Guided Thermal and Electromagnetic Mapping of RF Ablations

定量 MR 引导的射频消融热和电磁测绘

• 批准号: 7291644
• 负责人: John M. Pauly
• 金额: $ 30.35万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-26 至 2009-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7291644
• 关键词: Ablation; Adipose tissue; Algorithms; Animals; Clinical; Compatible; Deposition; Detection; Devices; Diagnostic; Electric Conductivity; Electrodes; Electromagnetics; Elements; Equation; Family suidae; Feasibility Studies; Frequencies; Goals; Heating; Image; Imaging Techniques; Intervention; Invasive; Lesion; Liver; Liver neoplasms; Magnetic Resonance Imaging; Maps; Measures; Methods; Monitor; Operative Surgical Procedures; Pathway interactions; Patients; Pattern; Performance; Physiologic pulse; Pliability; Procedures; Process; Protons; Pulse taking; Radiofrequency Interstitial Ablation; Resectable; Signal Transduction; Slice; Solutions; Standards of Weights and Measures; Survival Rate; System; Techniques; Temperature; Testing; Therapeutic; Thermometry; Time; Tissue Sample; Tissues; Update; Work; bone; cancer therapy; density; improved; in vivo; magnetic field; reconstruction; simulation; tool; treatment planning; tumor; vector

DESCRIPTION (provided by applicant): Radiofrequency ablation (RFA) is emerging as an effective image-guided minimally invasive therapeutic alternative to surgical treatment of cancer tumors. RFA appears well suited to nonresectable tumors in liver. The ablation process is highly dependent on the electrical conductivity of these tissues yet there is no easy way to predict the current pathways or how focused the current will be on the tumor. For example, bone and fatty pockets can shield tumor from ablation currents. Our goal is to enhance the planning and efficacy of tumor ablation by using an MRI system that can map RF ablation current pathways during ablation and map thermal changes. RF current maps will show where power is being deposited, and MR thermometry will show where heat flowed during the ablation. Our approach exploits a new MRI technique that images RF current density in tissue. The ablation electrode is injected with RF currents at the resonant frequency of the MRI scanner. The MRI scanner can directly image the intense magnetic fields associated with the ablation current, and then derive the map of current flow in tissue. In our preliminary work, we have already visualized the current flow in an MR compatible ablation electrode. These tests demonstrated that fatty tissue effectively insulates and blocks the ablation current. Moreover, the current pathway itself lights up high conductivity tissue and creates a medically significant contrast. To fully exploit this capability, we will merge RF current mapping with MR thermometry and ablation devices to form a comprehensive interventional MRI system for RF ablation. Enhanced RF hardware, pulse sequences and reconstructions will be developed. Upon completion, we will perform ex-vivo tissue sample and in-vivo animal studies to demonstrate the clinical potential of this system. If we achieve these goals, MR guided ablation imaging and thermal monitoring should enable better treatment planning for the ablation, and provide improved time and spatial monitoring as tumor ablation progresses. MR guided RF ablation gives the patient an effective option for a minimally invasive treatment of cancer tumors and a more controllable therapy.

描述（由申请人提供）：射频消融（RFA）正在成为癌症肿瘤手术治疗的一种有效的图像引导微创治疗替代方案。 RFA appears well suited to nonresectable tumors in liver.消融过程高度依赖于这些组织的电导率，但没有简单的方法来预测电流路径或电流在肿瘤上的聚焦程度。 For example, bone and fatty pockets can shield tumor from ablation currents.我们的目标是通过使用 MRI 系统来增强肿瘤消融的规划和功效，该系统可以在消融过程中绘制射频消融电流路径并绘制热变化图。 RF current maps will show where power is being deposited, and MR thermometry will show where heat flowed during the ablation. Our approach exploits a new MRI technique that images RF current density in tissue. The ablation electrode is injected with RF currents at the resonant frequency of the MRI scanner. MRI扫描仪可以直接对与消融电流相关的强磁场进行成像，然后得出组织中的电流图。 In our preliminary work, we have already visualized the current flow in an MR compatible ablation electrode. These tests demonstrated that fatty tissue effectively insulates and blocks the ablation current. Moreover, the current pathway itself lights up high conductivity tissue and creates a medically significant contrast.为了充分利用这一能力，我们将射频电流测绘与磁共振测温和消融设备相结合，形成一个用于射频消融的综合介入性 MRI 系统。 Enhanced RF hardware, pulse sequences and reconstructions will be developed. Upon completion, we will perform ex-vivo tissue sample and in-vivo animal studies to demonstrate the clinical potential of this system.如果我们实现这些目标，MR引导消融成像和热监测应该能够更好地制定消融治疗计划，并随着肿瘤消融的进展提供改进的时间和空间监测。 MR guided RF ablation gives the patient an effective option for a minimally invasive treatment of cancer tumors and a more controllable therapy.