INTERVENTIONAL MR: ADVANCED GUIDANCE/THERMAL MONITORING

使用开放式磁体系统，我们正在开发用于引导介入磁共振成像（IMRI）程序（包括热消融）的方法。 热消融是微创的并且具有成本效益。 介入性MRI不同于诊断性MRI，在我们的范例中，癌症肿瘤的微创治疗完全在MR成像仪中进行。 MRI既提供了介入器械对癌症肿瘤的引导，又提供了对热治疗的监测。这是通过利用MRI的以下能力来实现的：1）在肿瘤、正常组织、介入工具和热损伤之间产生对比，以及2）以任何角度获得图像（并且通过定位设备动态调整，如超声）。尽管如此，目前用于引导、定位和治疗监测的MRI技术存在局限性;除非克服这些局限性，否则IMRI将无法实现其在微创诊断和癌症治疗程序中的巨大潜力。 这些限制为开发和优化先进的磁成像脉冲序列技术创造了独特的机会，这些技术最终将通过更有效的IMRI功能改善患者护理。 该项目的研究将通过解决IMRI与诊断MRI不同的四个主要问题（这些问题必须同时实现）来创建满足IMRI环境约束的新成像方法：对比度：速度，运动不敏感性和治疗监测。 在IMRI中，患者风险与时间有关，因此我们将创建新的快速稳态自由旋进成像方法，具体应用于IMRI引导。 与目前可用于低场动态介入应用的方法相比，它们将在组织和介入器械之间实现更好的对比度。 将设计和评价利用介入器械方向信息的新径向K空间采样方法，以提高器械尖端精度，并降低对运动伪影的敏感性，优于IMRI中常用的2DFT方法。 对于原发性和转移性癌症的局部控制，最重要的解剖位置是肝、脑、肾、胰腺、头/颈和肌肉骨骼系统。 该应用程序中的研究将为这些解剖位置创建定制的IMRI方法，并在兔子（在腹部器官中植入VX 2）和猪上进行测试。 该项目将提供第一个系统性研究，其中低场IMRI技术是通过将MRI对比机制和K空间采样方案的优势结合在一起来设计的，以实现针对每个解剖位置的优化IMRI方法;它们将提供比几乎所有IMRI引导程序中使用的当前2DFT策略更好的性能。 此外，该项目将改进新兴的定量MR热成像方法，并实现IMRI指导的热癌症治疗的准确热监测。 基于我们迄今为止的成功，将创建第二代IMRI指导战略。

Using an open magnet system, we are developing methods for guiding interventional magnetic resonance imaging (IMRI) procedures including thermal ablation. Thermal ablation is minimally invasive and cost effective. Interventional MRI is different from diagnostic MRI, and in our paradigm, minimally invasive treatment of cancer tumors is performed entirely in the MR imager. MRI provides both guidance of the interventional device to the cancer tumor and monitoring the thermal treatment. This is a achieved by exploiting MRI's ability to: 1) generate contrast between tumors, normal tissues, interventional tools and thermal lesions and 2) obtain images at any angle (and dynamically adjusted, like ultrasound, via a localization device). Nonetheless, limitations exist in the current MRI techniques used for guidance, localization and treatment monitoring; unless overcome IMRI will not achieve it's vast potential in minimally invasive diagnostic and cancer treatment procedures. These limitations create a unique opportunity to develop and optimize advanced magnetic imaging pulse sequence techniques which will ultimately improve patient care through more effective IMRI capabilities. The research pursued in this project will create new imaging methods meeting the constraints of the IMRI environment by addressing four primary issues in which IMRI differs from diagnostic MRI (and these must be attained simultaneously): contrast: speed, motion insensitivity and therapy monitoring. In IMRI patient risk is related to time, and so we will create new rapid steady state free precession imaging methods with specific application for IMRI guidance. They will achieve better contrast between tissues and interventional devices than methods presently available for low field dynamic interventional applications. New radial K-space sampling methods which utilize information on the orientation of the interventional device will be designed and evaluated to improve the device tip accuracy and reduce sensitivity to motion artifacts better than 2DFT methods used commonly in IMRI. The most important anatomic locations for local control of primary and metastatic cancer are the liver, brain, kidney, pancreas, head/neck and musculoskeletal system. The research in this application will create customized IMRI methods for these anatomic locations and test them on rabbits (implanted with VX2 in the abdominal organs) and pigs. This project will provide the first systematic study in which low field IMRI techniques are designed by combining the advantages of both the MRI contrast mechanism and K-space sampling scheme together to achieve optimized IMRI methods for each anatomic location; they will offer greater performance than current 2DFT strategies used in virtually all IMRI guided procedures. Further, this project will improve emerging quantitative MR thermal mapping methods and allow attainment of accurate thermal monitoring of IMRI guided thermal cancer therapy. Based on our success to date, the second generation of IMRI guidance strategies will be created.