Image-Guided Monitoring of Meningioma Embolization in a Combined MRI/XRA Suite

描述（由申请人提供）：脑膜瘤的诊断通常通过常规CT和/或MR成像来确定肿瘤的形态和成分。如果脑膜瘤血管丰富并计划切除，术前栓塞有助于减少手术时间和术中出血量。在常规实践中，进行诊断性动脉造影以识别血液供应并评估栓塞的安全性和可行性，并且如果认为合适，则递送栓塞材料以产生血管阻断和随后的肿瘤坏死。X射线荧光透视具有出色的空间和时间分辨率，但其局限性在于，它是一种投影模态，不能提供感兴趣区域的完整3D分析。初步结果表明，它是不太敏感的对比剂的运输比灌注MRI，并具有有限的能力，提取功能参数，如灌注时间常数或流速。因此，X线透视可能无法识别所有可从栓塞中获益的患者。介入性磁共振成像是有吸引力的，因为它的敏感性动脉内注射的磁共振造影剂和它的能力，以确定功能参数。然而，由于担心与加热相关的损伤，在介入MRI环境中适合人类使用的导管必须是无金属的，这限制了该技术的广泛传播。本项目的目的是确定MR灌注和X线透视在确定哪些脑膜瘤适合栓塞方面的相对能力。该项目将进一步评估MR灌注时间曲线是否可以确定肿瘤血管分布的相对贡献，这些血管分布来自颈外动脉与颈内动脉，以及MR灌注时间曲线的静脉内测量是否能够提供与动脉内测量相似的数据。如果是这样的话，该项目可以确定静脉内MR是否可以识别那些不适合栓塞治疗的患者，从而使他们免于侵入性动脉造影。最后，本项目将调查，在一系列精心控制的模型实验中，是否可以使用具有合适成像参数的特定脉冲序列，而不会导致某些金属包层导管的不良加热。公共卫生相关性：本研究将确定MR是否可用于更有效地对脑膜瘤栓塞患者进行分期，如果栓塞无效，则患者无需进行导管插入，并包括将从栓塞中受益的患者，以及仅基于X线透视评价可能无法获得该受益的患者。此外，令人满意的证明，在MR条件下，金属包层导管可以安全使用，这将使扩大的能力，不仅用于治疗脑膜瘤，但在广泛的令人兴奋的应用，目前被认为是无法接近的。本研究将确定MR是否可用于更有效地对脑膜瘤栓塞患者进行分期，如果栓塞无效，则患者无需进行导管插入，并包括将从栓塞中受益的患者，以及仅基于X线透视评价可能无法获得该受益的患者。此外，令人满意的证明，在MR条件下，金属包层导管可以安全使用，这将使扩大的能力，不仅用于治疗脑膜瘤，但在广泛的令人兴奋的应用，目前被认为是无法接近的。

DESCRIPTION (provided by applicant): Diagnosis of a meningioma is generally established by routine CT and/or MR imaging that determines the tumor morphology and composition. If the meningioma is fairly vascular and resection is planned, preoperative embolization is helpful in diminishing operative time and intraoperative blood loss. In routine practice, a diagnostic arteriogram is performed to identify blood supply and to assess the safety and feasibility of embolization, and if deemed appropriate, embolic material is then delivered to produce devascularization and subsequent necrosis of the tumor. X-ray fluoroscopy has excellent spatial and temporal resolution but is limited in that it is a projection modality that does not provide a full 3D analysis of the territory of interest. Preliminary results indicate that it is less sensitive to the transit of contrast material than is perfusion MRI, and has a limited ability to extract functional parameters, such as perfusion time constants or flow velocities. It is therefore likely that x-ray fluoroscopy fails to identify all patients who would benefit from embolization. Interventional MRI is attractive because of its sensitivity to intra-arterial injections of MR contrast agents and its ability to determine functional parameters. However, catheters suitable for human use in the interventional MRI setting must be metal-free because of concerns of heating-related injury, restricting the wide dissemination of this technology. The goal of this project is to determine the relative capability of MR perfusion and x-ray fluoroscopy in determining which meningiomas are candidates for embolization. This project will further assess whether MR perfusion time curves can determine the relative contribution of tumor vascularity that arises from the external versus the internal carotid artery, and whether intra-venous measurements of MR perfusion time curves are able to provide similar data to that of intra-arterial measurements. If that is the case, this project could establish whether intra- venous MR can identify those patients who are not candidates for embolization therapy, thereby sparing them an invasive arteriogram. Finally, this project will investigate, in a series of carefully controlled model experiments, whether specific pulse sequences with suitable imaging parameters can be used without causing untoward heating in certain metal-clad catheters. Public Health Relevance: This study will determine if MR can be used to more effectively stage patients for meningioma embolization, sparing patients from catheterization if embolization will not be effective, and including patients who would benefit from embolization, and who might not receive that benefit on the basis of x-ray fluoroscopy evaluation, alone. In addition, satisfactory demonstration of MR conditions under which metal-clad catheters could be safely used would enable expanded capabilities, not only for treatment of meningiomas, but in a broad range of exciting applications that are currently considered unapproachable. This study will determine if MR can be used to more effectively stage patients for meningioma embolization, sparing patients from catheterization if embolization will not be effective, and including patients who would benefit from embolization, and who might not receive that benefit on the basis of x-ray fluoroscopy evaluation, alone. In addition, satisfactory demonstration of MR conditions under which metal-clad catheters could be safely used would enable expanded capabilities, not only for treatment of meningiomas, but in a broad range of exciting applications that are currently considered unapproachable.