标题： 基于True FISP读出的3T下3D单次采集CEST成像 显示英文标题

标题： 3D Single-shot CEST imaging at 3T Based on True FISP Readout

摘要： 为了同时拟合多池效应，光谱选择性3D CEST成像通常需要单次读出以节省时间。 然而，到目前为止，FLASH和EPI一直是用于此目的的主要脉冲序列。 它们存在信噪比低或由于B0场不均匀性导致的图像失真问题。 在本研究中，我们开发了一种使用真实稳态进动快速成像（True FISP）读出的3D单次读出CEST序列，也称为bSSFP，并通过模拟优化了扫描参数。 该CEST序列的性能使用鸡蛋清幻影、十名健康志愿者和一名脑肿瘤患者在3T人体扫描仪上进行了验证。 随后，所提出的使用True FISP的CEST序列与常用的基于FLASH的CEST序列进行了比较，重点比较了信噪比和图像对比度，同时保持相同的预饱和模式、重复时间、回波时间和扫描时间。 在模拟实验中，从True FISP获得的最大CEST信号明显大于从FLASH序列获得的信号。 在鸡蛋清幻影中，从True FISP获得的酰胺质子转移（APT）和核Overhauser增强（NOE）效应图像的信噪比分别比从FLASH序列获得的高68.3%和57.0%。 在健康志愿者中，使用True FISP序列在3.5 ppm处获得的饱和图像的平均时间信噪比相比使用FLASH序列获得的图像提高了约84%。 与FLASH序列相比，从True FISP序列获得的CEST图像能够显示正常个体和脑肿瘤患者的更详细的脑组织结构。 因此，由于该序列本身具有高信噪比，True FISP有望用于临床应用中CEST对比的快速高质量3D图像读出。 显示英文摘要

摘要： To simultaneously fit multiple-pool effects, spectrally selective 3D CEST imaging typically requires single-shot readouts to save time. However, to date, FLASH and EPI have been the primary pulse sequences used for this purpose. They suffer from low SNR or image distortion related to B0 field inhomogeneity. In this work, we developed a 3D single-shot CEST sequence using true fast imaging with steady-state precession (True FISP) readout, also known as bSSFP, and optimized the scanning parameters through simulations. The performance of the CEST sequence was validated using an egg white phantom, ten healthy volunteers, and a patient with a brain tumor on a 3T human scanner. Subsequently, the proposed CEST sequence using True FISP was compared with the commonly used FLASH-based CEST sequence, focusing on SNR and image contrast, while maintaining identical pre-saturation modes, repetition time, echo time and scan time. In the simulation experiments, the maximum CEST signal obtained from the True FISP was significantly greater than that obtained from the FLASH sequence. In the egg white phantom, the SNRs of amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) effect images obtained from the True FISP were 68.3% and 57.0% higher than those obtained from the FLASH sequence, respectively. In healthy volunteers, saturated images collected with the True FISP sequence at 3.5 ppm showed an approximate 84% increase in mean temporal SNR compared to those collected with the FLASH sequence. Compared to the FLASH sequence, the CEST images obtained from the True FISP sequence could display more detailed brain tissue structures of both normal individuals and the patient with a brain tumor. Therefore, due to the high SNR inherent in the sequence, True FISP has the potential to be used for fast and high-quality 3D image readout of CEST contrasts in clinical applications.