Fast Targeted Spectroscopic Imaging for Brain Tumor Imaging at 3T and 7T

磁共振波谱成像(MRSI)已被证明为 脑肿瘤、癫痫、多发性硬化症和创伤性脑损伤的诊断和治疗。尽管 与单一体积测量相比，成像方法具有明显的优势，临床上，大多数MRS研究是 仍以单体素研究的形式进行。不愿将磁共振成像纳入临床评估的主要原因是 来自四个因素：1)采集时间增加；2)数据采集时间过长时频谱质量受限 更大的大脑区域；3)信噪比的限制；4)对皮质外围进行采样的挑战。要克服 针对这些局限性，我们将开发一种快速的MRSI方法(5-10分钟。)它使用：1)二维玫瑰花环 对轨迹进行编码以在两个维度上快速采样大脑，同时将梯度需求降至最低 提高光谱质量；2)在第三维中进行Hadamard编码以最小化局部化伪影 为覆盖最相关大脑区域的较小数量的分区(4-8个)提供出色的切片配置文件； 3)高度垫片，以最大限度地提高磁场均匀度和提高频谱质量；4) 动态空间选择性消相，以最大限度地提高信噪比，并对皮质边缘进行采样。与一致 目前最广泛接受的MRS临床应用是什么，我们将在患者中对这些方法进行评估 接受免疫治疗的高级别脑瘤患者。尽管免疫疗法是一种非常有前途的新技术 脑肿瘤的治疗方法，治疗效果可以在常规MRI上模拟肿瘤的进展， 损害了我们有效监测和管理这些患者的能力。MRSI提供了另一种方法来 监测进展，基于肿瘤新陈代谢和生理，而不是组织的松弛特性 水(常规核磁共振)。因此，我们认为MRSI可以提供附加值，并在很大程度上帮助 这些病人的管理。这项工作将在3T和7T进行。

Magnetic Resonance Spectroscopic Imaging (MRSI) has proven to provide unique information for the diagnosis and management of brain tumors, epilepsy, multiple sclerosis and traumatic brain injury. Despite the obvious advantage of imaging approaches over single volume measurements, clinically, most MRS studies are still performed as single voxel studies. The reluctance to include MRSI in clinical evaluations arises primarily from four factors: 1) increased acquisition times; 2) limitations in spectral quality when data is acquired over larger brain regions; 3) limitations in SNR and 4) challenges in sampling the cortical periphery. To overcome these limitations we will develop a fast MRSI method (5-10min.) which uses: 1) two dimensional rosette encoding trajectories to rapidly sample the brain in two dimensions while minimizing gradient demands and improve spectral quality; 2) Hadamard encoding in the third dimension to minimize localization artifacts and provide excellent slice profiles for smaller numbers of partitions (4-8) covering the most relevant brain region; 3) a high degree shim insert to maximize magnetic field homogeneity and improve spectral quality and 4) dynamic spatially selective dephasing to maximize SNR and sample the cortical periphery. Consistent with what is the most widely accepted MRS clinical application currently, we will evaluate the methods in patients with high-grade brain tumors receiving immunotherapy. Although immunotherapy is a highly promising new therapeutic approach for brain tumors, treatment effects can mimic tumor progression on conventional MRI, compromising our ability to effectively monitor and manage these patients. MRSI offers an alternative means to monitor progression, based on tumor metabolism and physiology as opposed to relaxation properties of tissue water (conventional MRI). Thus we believe that MRSI may provide additive values and significantly aid in the management of these patients. This work will be performed at 3T and 7T.