INTERVENTIONAL MR: ADVANCED GUIDANCE/THERMAL MONITORING

使用开放式磁铁系统，我们正在开发指导介入磁共振成像（IMRI）程序的方法，包括热消融。热消融具有微创性和成本效益。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是在磁共振成像仪中进行的。MRI提供了介入装置对肿瘤的引导和热治疗的监测。这是通过利用MRI的能力来实现的：1)在肿瘤、正常组织、介入工具和热病变之间生成对比；2)获得任何角度的图像（并通过定位设备动态调整，如超声）。然而，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IMRI，否则它在微创诊断和癌症治疗程序中的巨大潜力将无法实现。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一个独特的机会，这将最终通过更有效的IMRI功能改善患者护理。本项目所进行的研究将通过解决IMRI与诊断性MRI不同的四个主要问题（这些问题必须同时得到）来创造新的成像方法，以满足IMRI环境的限制：对比、速度、运动不敏感和治疗监测。在IMRI中，患者的风险与时间有关，因此我们将创造新的快速稳态自由进动成像方法，并具体应用于IMRI指导。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装置之间实现更好的对比。将设计和评估新的径向k空间采样方法，该方法利用介入设备的方向信息，以提高设备尖端精度，降低对运动伪影的灵敏度，优于IMRI中常用的2DFT方法。原发性和转移性癌症的局部控制最重要的解剖部位是肝脏、大脑、肾脏、胰腺、头颈部和肌肉骨骼系统。该应用程序的研究将为这些解剖位置创建定制的IMRI方法，并在兔子（在腹部器官植入VX2）和猪身上进行测试。本项目将提供第一个系统的研究，通过结合MRI对比机制和k空间采样方案的优势，设计低场IMRI技术，以实现针对每个解剖位置的优化IMRI方法；它们将提供比目前几乎所有IMRI指导程序中使用的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，并允许实现IMRI引导的热癌症治疗的精确热监测。基于我们迄今取得的成功，第二代IMRI指导策略将被创建。

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.