Passive Cavitation Imaging for Guidance and Control of Ultrasound Ablation

用于引导和控制超声消融的被动空化成像

• 批准号: 7571142
• 负责人: T Douglas Mast
• 金额: $ 20.02万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7571142
• 关键词: Ablation; Accounting; Acoustics; Algorithms; Cattle; Clinical; Coagulation Process; Data; Deposition; Development; Excision; Family suidae; Feedback; Frequencies; Furuncles; Future; Goals; Heating; Histologic; Histology; Image; Imaging technology; In Situ; In Vitro; Individual; Investigation; Liver; Location; Malignant Neoplasms; Malignant neoplasm of liver; Maps; Measurement; Measures; Methods; Microbubbles; Microscopic; Modality; Modeling; Necrosis; Outcome; Patients; Pattern; Public Health; Recurrence; Research; Resolution; Safety; Saline; Signal Transduction; Simulate; Soft Tissue Neoplasms; Sonication; Source; Specific qualifier value; Statistical Models; System; Temperature; Therapeutic; Thermal Ablation Therapy; Time; Tissue Viability; Tissues; Transplantation; Ultrasonics; Ultrasonography; acoustic imaging; attenuation; base; cancer therapy; clinical application; imaging modality; improved; in vivo; minimally invasive; mortality; new technology; physical model; pre-clinical; public health relevance; research study; tumor

DESCRIPTION (provided by applicant): The overall goal of this project is to develop the novel technology of passive cavitation imaging for guidance and control of thermal ablation. This investigation is based on the hypothesis that cavitation, or microbubble activity caused by therapeutic ultrasound beams, can be passively imaged by ultrasound arrays, providing specific information about spatially-dependent sonication intensity, temperature, and tissue viability in vivo. In passive cavitation imaging, ultrasound-induced microbubble activity within tissue is mapped noninvasively from locally occurring acoustic emissions caused by cavitation and boiling. These acoustic emissions are detected passively by an ultrasound imaging array, filtered, and synthetically focused to form images depicting locations and strengths of stable cavitation, inertial cavitation, and tissue boiling throughout the imaged region. Preliminary data indicates that these passive cavitation images can accurately depict spatial profiles of therapeutic ultrasound beams in situ, resolve individual sources of cavitation-induced acoustic emissions, and be used to predict local tissue temperature elevations causing thermal coagulation necrosis. This cavitation imaging technology will provide previously unavailable guidance and control for ultrasound ablation, greatly enhancing this modality for noninvasive and minimally invasive cancer treatment. The proposed research will begin with optimization of methods for passive cavitation imaging, including filtering and beamforming of acoustic emission signals to maximize image resolution, sensitivity, and quantitative accuracy. Optimized passive cavitation imaging methods will be used to map localized stable and inertial cavitation in saline solution and ex vivo liver tissue, measuring cavitation thresholds as functions of temperature and sonication amplitude. Passive cavitation images will be acquired during therapeutic ultrasound exposures both on bovine liver in vitro and porcine liver in vivo. Measured correlations between passive cavitation images, tissue temperature, and tissue histologic changes during ultrasound ablation, with complementary physical modeling and statistical analysis, will guide development of control strategies for ultrasound ablation. Multivariate statistical models based on experimental data will predict local tissue temperature and coagulation based on imaged acoustic emissions in the three bands considered, allowing specification of treatment progress indicators and end points for ultrasound ablation. Feasibility of this approach for closed-loop ultrasound ablation control will be assessed, based on measured accuracy of these new models for prediction of local tissue ablation. Successful completion of this project will show feasibility for future development of a clinical system providing guidance and control of ultrasound ablation by passive cavitation imaging. These guidance and control methods will provide greatly improved efficacy and safety for ultrasound ablation of liver cancer and soft tissue tumors as well as other clinical applications. PUBLIC HEALTH RELEVANCE: Liver cancer, both primary and metastatic, is a major public health problem, accounting for the largest cancer- related mortality in the world, with only a small fraction of patients eligible for curative resection or transplantation. Minimally invasive and noninvasive ablation methods provide an important alternative but have significant problems with incomplete treatment, tumor recurrence, and complications caused by imprecise treatment. Ultrasound ablation is a particularly promising approach, potentially offering more precise and reliable treatment, but will not realize its full potential without effective feedback, control and image guidance. Our passive cavitation imaging technology has the potential to greatly improve guidance and control of minimally-invasive and noninvasive ultrasound tumor ablation, providing more precise, selective, predictable, and consistent ablation of liver cancer as well as soft tissue tumors and other clinically important targets, and thus fewer complications, reduced tumor recurrence, and improved patient outcomes.

描述（由申请人提供）：本项目的总体目标是开发用于引导和控制热消融的被动空化成像新技术。这项调查是基于这样的假设，即治疗性超声波束引起的空化或微泡活动可以通过超声阵列被动成像，提供有关空间依赖性声处理强度、温度和体内组织活力的特定信息。在被动空化成像中，组织内超声诱导的微泡活动由空化和沸腾引起的局部发生的声发射非侵入性地映射。这些声发射由超声成像阵列被动地检测、滤波并合成地聚焦以形成描绘整个成像区域中的稳定空化、惯性空化和组织沸腾的位置和强度的图像。初步数据表明，这些被动空化图像可以准确地描绘空间分布的治疗超声波束在原位，解决个别来源的空化引起的声发射，并被用来预测局部组织温度升高引起热凝固坏死。这种空化成像技术将为超声消融提供以前无法提供的指导和控制，大大增强了这种无创和微创癌症治疗方式。拟议的研究将开始与被动空化成像的方法优化，包括过滤和声发射信号的波束形成，以最大限度地提高图像分辨率，灵敏度和定量精度。优化的被动空化成像方法将用于映射生理盐水溶液和离体肝组织中的局部稳定和惯性空化，测量作为温度和超声振幅函数的空化阈值。在治疗性超声暴露过程中，将在体外牛肝和体内猪肝上采集被动空化图像。超声消融过程中测量的被动空化图像、组织温度和组织组织学变化之间的相关性，以及补充的物理建模和统计分析，将指导超声消融控制策略的开发。基于实验数据的多变量统计模型将基于所考虑的三个频带中的成像声发射来预测局部组织温度和凝固，从而允许规范超声消融的治疗进展指标和终点。将根据这些新模型预测局部组织消融的测量精度，评估这种方法用于闭环超声消融控制的可行性。该项目的成功完成将表明未来开发通过被动空化成像提供超声消融引导和控制的临床系统的可行性。这些引导和控制方法将为肝癌和软组织肿瘤的超声消融以及其他临床应用提供大大提高的有效性和安全性。 公共卫生相关性：原发性和转移性肝癌是一个主要的公共卫生问题，占世界上最大的癌症相关死亡率，只有一小部分患者符合治愈性切除或移植的条件。微创和非侵入性消融方法提供了一种重要的替代方案，但存在治疗不完全、肿瘤复发和不精确治疗引起的并发症等重大问题。超声消融是一种特别有前途的方法，可能提供更精确和可靠的治疗，但如果没有有效的反馈，控制和图像引导，将无法实现其全部潜力。我们的无源空化成像技术有可能极大地改善微创和无创超声肿瘤消融的引导和控制，为肝癌以及软组织肿瘤和其他临床重要目标提供更精确，选择性，可预测和一致的消融，从而减少并发症，减少肿瘤复发，改善患者预后。