Multi-point MR-ARFI for time-efficient volumetric tissue stiffness imaging

标题：多点MR-ARFI用于时间有效的体积组织硬度成像 检测和表征指示坏死的组织特性变化的能力对于以下方面是必不可少的： 成功控制消融治疗。当组织被消融时，细胞结构发生变化， 组织水，以及大分子结构的性质。成像技术，区分和 精确地表征组织特性变化是确保消融治疗成功的关键。 聚焦超声（FUS）是一种完全无创且极具前景的介入技术， 能够消融一系列病变，迫切需要改进的方法来检测、监测和解释 导致组织性质的变化。FUS（MRgFUS）程序的MRI引导提供了极好的 待治疗组织和待保留的正常组织的解剖图像，并且可以监测温度 水（非脂肪）组织中的分布变化，以确保治疗有效性和安全性。诊断 当用于引导FUS（USgFUS）程序时，超声具有差的解剖图像质量和有限的 测量温度的能力，但可以成像组织硬度和机械特性， 治疗尽管MRI可以根据由声学干扰引起的位移来测量组织硬度， 辐射力脉冲（MR-ARFI），力通常施加在单个点上，仅提供局部 组织硬度的测量。虽然MR-ARFI可以以一定的成本顺序询问多个位置， 由于采集时间的增加，没有一种时间有效的方法来同时询问分布 多处组织僵硬 我们在这项研究中的目标是开发和评估一种时间效率高的体积组织MR-ARFI方法 刚度成像这一目标将通过三个目标来实现：1）执行和评估以下方面的效率： 交错多个单点MR-ARFI测量; 2）实现和评估同时或接近 同时多点MR-ARFI方法; 3）评价多点MR-ARFI方法的准确性和重复性 MR-ARFI位移测量。 这种体积刚度成像的新方法将使未来的研究能够测量组织刚度 在MRgFUS程序之前、期间和之后， 诸如手术期间的热剂量和手术后组织的组织学状态的因素。 评估FUS施加力引起的组织位移将允许有效的远程触诊 由MRgFUS治疗在治疗期间的多个位置和时间形成的演变的热损伤。 procedure.如果这种硬度变化是坏死的指标，这将增加信息量 以确定一个成功的结果。

Title: Multi-point MR-ARFI for time-efficient volumetric tissue stiffness imaging The ability to detect and characterize changes in tissue properties that are indicative of necrosis is essential for successful control of ablative therapies. As tissue is ablated, changes occur in cell structure, in the distribution of tissue water, and in the nature of the macromolecular structure. Imaging techniques that discriminate and accurately characterize tissue property changes are critically needed to ensure ablative therapy success. Focused ultrasound (FUS), a completely non-invasive and highly promising interventional technology that is able to ablate a range of pathologies, has a critical need for improved methods to detect, monitor, and interpret the resulting changes in tissue properties. MRI guidance of FUS (MRgFUS) procedures provides excellent anatomic images of tissues to be treated and normal tissues to be spared, and can monitor temperature distribution changes in aqueous (non-adipose) tissues to ensure treatment efficacy and safety. Diagnostic ultrasound, when used for guiding FUS (USgFUS) procedures, has poor anatomic image quality and limited ability to measure temperature, but can image tissue stiffness and mechanical properties that change with treatment. Although MRI can measure tissue stiffness in terms of displacement caused by an acoustic radiation force impulse (MR-ARFI), the force is typically applied at a single point, providing only a local measurement of tissue stiffness. Although MR-ARFI could sequentially interrogate multiple positions at a cost of increased acquisition time, there is not a time efficient method to simultaneously interrogate the distribution of tissue stiffness at multiple points. Our goal in this study is to develop and evaluate a time-efficient MR-ARFI method for volumetric tissue stiffness imaging. This goal will be accomplished with three aims: 1) Implement and evaluate efficiencies in interleaving multiple single-point MR-ARFI measurements; 2) Implement and evaluate simultaneous or near simultaneous multiple-point MR-ARFI methods; 3) Evaluate the accuracy and repeatability of multiple point MR-ARFI displacement measurements. This new method of volumetric stiffness imaging will enable future studies to measure tissue stiffness properties before, during, and after MRgFUS procedures, and to correlate tissue property changes with other factors such as thermal dose during the procedure and the histologic state of the tissue after the procedure. Assessing tissue displacement in response to the applied force of FUS will allow an effective remote palpation of the evolving thermal lesion formed by the MRgFUS treatment at multiple positions and times during the procedure. If this stiffness change is an indicator of necrosis, this will increase the amount of information available to determine a successful outcome.