MRI-guided High Intensity Focused Ultrasound Ablation of Uterine Fibroids

MRI引导下高强度聚焦超声消融子宫肌瘤

• 批准号: 7968829
• 负责人: pamela stratton
• 金额: $ 46.5万
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7968829
• 关键词: Ablation; Adverse event; Animal Experiments; Animals; Area; Caliber; Cell Size; Cells; Clinical Research; Detection; Dose; Ensure; FDA approved; Feedback; Fibroid Tumor; Focused Ultrasound Therapy; Heating; Histology; Hysterectomy; Leiomyoma; Length of Stay; Lesion; Link; Location; Magnetic Resonance Imaging; Measurement; Measures; Monitor; Necrosis; Normal tissue morphology; Operative Surgical Procedures; Organ; Pain; Pelvis; Pilot Projects; Postoperative Period; Procedures; Radial; Risk; Safety; Sonication; Speed; Spottings; System; Techniques; Temperature; Thermometry; Time; Tissues; Transducers; Ultrasonography; United States; Upper arm; Uterine Fibroids; Uterine hemorrhage; Uterus; Visual; Woman; aged; capsule; improved; novel; prevent; reproductive; software systems; treatment planning

Uterine fibroids (leiomyomas) are a common cause of heavy uterine bleeding and pain in reproductive aged women and are the most common cause of hysterectomy in the United States. Women are seeking new ways to treat symptomatic uterine fibroids that allow them to avoid surgery. This study is the first step in this quest. We will study the novel use of magnetic resonance imaging (MRI) in enhancing the safety of the FDA approved technique to treat fibroids called High Intensity Focused Ultrasound (HIFU). The term high intensity focused ultrasound means using ultrasound to heat and to thermally destroy tissue, in this case, uterine fibroids. The MRI system will allow us to watch the ultrasound path during treatment and monitor the temperature increase in the fibroid tissue that comes during the procedure. Similar to existing HIFU systems, the Philips system enables ablation of uterine fibroids under MR image guidance. However, the Philips system adds two unique features to existing MR guided HIFU therapy, which have the potential to reduce treatment times and improve safety compared to existing MR guided HIFU systems. These are the use of volumetric ablation and automated thermal feedback. Volumetric heating refers to the use of a rotating focal spot, which is moved electronically in a circular path with a fixed radius at high speed. This enables heating of larger zones or cells in one sonication compared with point by point sonication used by existing HIFU systems. Point by point sonication delivers HIFU using a fixed focal spot that moves in a pre-determined raster or grid layout of treatment cells arranged in rows and columns. During volumetric sonication, the transducer applies heat in a continuous circular manner to adjacent points within the treatment cell. These treatment cells, with diameters of 4, 8, or 12 mm, are placed within a target treatment area to make up the planned treatment volume (PTV). Treatment is performed by stepping through several treatment cell ablations with cooling times between each sonication. Each HIFU volumetric cell ablation is performed with an ultrasound power level set to achieve a tissue heating of 50 70C. The duration of the exposures are linked with the cell size, and are fixed by the system. Volumetric treatment allows for complete and uniform cell coverage, with the potential to reduce treatment time compared to existing MR guided HIFU systems. In animal experiments comparing the use of volumetric ablation to rastered, or point by point sonication, volumetric sonication has been shown to have treatment speeds up to 7 times faster with the use of the 12 mm volumetric cell than with the use of a single point ablation of the same size. The Philips HIFU system also allows volumetric heating to be performed with automated thermal feedback. When automated thermal feedback is enabled, the duration of sonication will be limited by the measured thermal dose in the cell, as detected by MR thermometry. For example, if optimal thermal dose as measured by MR is reached prior to 20 seconds in the case of a 4-mm treatment cell, the sonication is stopped by the system software, preventing tissue overheating. Existing MR guided HIFU systems rely entirely on the operators detection of elevated thermal doses in order to stop the treatment. The use of automated thermal feedback has the added benefit of ensuring delivery of optimal thermal dose and improving safety by minimizing the risk of overheating and thus overtreatment. In this pilot study, women with symptomatic fibroids will undergo MRI guided HIFU and then have a hysterectomy. This will allow us to confirm studies done in animals which show that it is possible to destroy specific tissue without harming normal tissue surrounding the targeted area.

子宫肌瘤（平滑肌瘤）是育龄妇女严重子宫出血和疼痛的常见原因，也是美国子宫切除术的最常见原因。 女性正在寻找新的方法来治疗有症状的子宫肌瘤，从而避免手术。 这项研究是这一探索的第一步。 我们将研究磁共振成像 (MRI) 的新用途，以提高 FDA 批准的高强度聚焦超声 (HIFU) 肌瘤治疗技术的安全性。 高强度聚焦超声一词意味着使用超声加热并热破坏组织，在本例中为子宫肌瘤。 MRI 系统将使我们能够在治疗过程中观察超声路径，并监测手术过程中肌瘤组织的温度升高。 与现有的 HIFU 系统类似，飞利浦系统能够在 MR 图像引导下消融子宫肌瘤。然而，飞利浦系统为现有的 MR 引导 HIFU 治疗增加了两个独特的功能，与现有的 MR 引导 HIFU 系统相比，这有可能减少治疗时间并提高安全性。这些是体积消融和自动热反馈的使用。 体积加热是指使用旋转焦点，该焦点以电子方式沿固定半径的圆形路径高速移动。与现有 HIFU 系统使用的逐点超声处理相比，这可以在一次超声处理中加热更大的区域或细胞。逐点超声处理使用固定焦点进行 HIFU，该焦点在按行和列排列的处理单元的预定光栅或网格布局中移动。在体积超声处理过程中，换能器以连续圆形方式向处理单元内的相邻点施加热量。这些直径为 4、8 或 12 毫米的治疗单元被放置在目标治疗区域内，以构成计划治疗体积 (PTV)。治疗是通过逐步进行多次治疗细胞消融以及每次超声处理之间的冷却时间来进行的。每次 HIFU 体积细胞消融均采用设定的超声功率水平进行，以实现 50 70°C 的组织加热。暴露的持续时间与细胞大小相关，并由系统固定。体积治疗可实现完整且均匀的细胞覆盖，与现有 MR 引导的 HIFU 系统相比，有可能减少治疗时间。在动物实验中，将体积消融与光栅或逐点超声处理的使用进行比较，结果表明，使用 12 毫米体积池的体积超声处理速度比使用相同尺寸的单点消融快 7 倍。 飞利浦 HIFU 系统还允许通过自动热反馈进行体积加热。当启用自动热反馈时，超声处理的持续时间将受到 MR 测温法检测到的细胞内测量的热剂量的限制。例如，如果在 4 毫米治疗池的情况下，在 20 秒之前达到 MR 测量的最佳热剂量，则系统软件会停止超声处理，以防止组织过热。现有的 MR 引导 HIFU 系统完全依赖操作员检测到热剂量升高来停止治疗。使用自动热反馈具有额外的好处，即确保提供最佳热剂量，并通过最大限度地降低过热和过度治疗的风险来提高安全性。 在这项试点研究中，有症状的子宫肌瘤女性将接受 MRI 引导的 HIFU，然后进行子宫切除术。 这将使我们能够证实在动物身上进行的研究，这些研究表明可以破坏特定组织而不伤害目标区域周围的正常组织。