State of the Art 3T Research Scanner

 描述(由申请人提供)：我们建议购买最先进的3T磁共振扫描仪(西门子Magnetom Prisma)，以更换我们在肯尼迪克里格Hugo Moser研究所(KKI)的F.M.Kirby研究中心报废的3Tesla飞利浦研究扫描仪，该扫描仪无法升级到最新的数字飞利浦Achieva系统。这种扫描仪更换是必要的，以满足KKI和约翰·霍普金斯大学(JHU)的许多研究人员的需求，他们拥有15笔由NIH资助的赠款，其具体目标是从这次升级提供的改进的技术能力中受益匪浅。这些研究人员使用3T系统进行结构核磁共振、功能核磁共振(FMRI)、定量生理核磁共振、磁共振波谱(MRS)和光谱成像(MRSI)，以及扩散张量成像(DTI)用于研究人类行为以及各种疾病和发育障碍。PRISMA对我们来说重要的主要特点是：1)具有最高同时强度(80mT/m)和转换速率(200mT/m/S)的磁场梯度硬件；2)具有3)128个接收通道的全数字射频(RF)发射/接收系统；4)通道头颈部线圈；5)改进的场和频率稳定性；6)从西门子和领导人类连接组计划(HCP)的高级西门子用户那里获得先进的同步多切片(SMS)和多频段(MB)包；7)我们将在完全用户控制的MRI扫描仪上拥有可用的最快重建计算机。该扫描仪将为我们的用户提供广泛的好处，包括但不限于：由于数字接收系统中的噪声降低，提高了所有应用的信噪比(SNR)，可用于更好地检测小信号、更精细的空间分辨率和/或更快的扫描。由于具有更高的梯度强度(更短的扩散时间)和转换速率(更短的读出时间)可以获得更短的回波时间(TE)，因此DTI扫描的SNR进一步增加。128个接收通道的可用性为未来的高端“连接型”射频硬件提供了一条道路。第一个商用的通道线圈预计将提供比32通道略有改善的SNR，以及改进的g因子，用于并行成像，特别是在SMS/MB成像中控制混叠。与我们目前的系统相比，频率稳定度的提高将带来以下好处：a)提高动态扫描的信号强度稳定性；b)在高占空比梯度下没有空间图像漂移，例如在具有多方向和强扩散加权的扩散光谱成像(DSI)中使用；c)通过选择性脉冲激励改进频谱编辑；d)改进CEST-MRI频率参考。最后，重建计算机的用户控制允许在扫描仪上处理HCP类型的采集序列和实时运动校正算法。

 DESCRIPTION (provided by applicant): We propose to purchase a state of the art 3T MRI scanner (Siemens MAGNETOM Prisma) in order to replace our end-of-life 3 Tesla Philips research scanner at the F.M. Kirby Research Center of the Hugo Moser Research Institute at Kennedy Krieger (KKI), which cannot be upgraded to the newest digital Philips Achieva system. This scanner replacement is necessary to address the needs of many investigators at the KKI and Johns Hopkins University (JHU) who have 15 NIH-funded grants with specific aims that strongly benefit from the improved technical capabilities provided by this upgrade. These investigators use the 3T system for structural MRI, functional MRI (fMRI), quantitative physiological MRI, magnetic resonance spectroscopy (MRS) and spectroscopic imaging (MRSI), and diffusion tensor imaging (DTI) for the study of human behavior and a large range of diseases and developmental disabilities. The main features of importance for us on the Prisma are availability of 1) magnetic field gradient hardware with the highest simultaneous strength (80 mT/m) and slew rate (200 mT/m/s), 2) a completely digital radiofrequency (RF) transmit/receive system with 3) 128 receive channels; 4) a 64-channel head and neck coil; 5) improved field and frequency stability; 6) availability of advanced simultaneous multi-slice (SMS) and multiband (MB) packages both from Siemens and from advanced Siemens users leading the human connectome project (HCP); 7) we will have the fastest reconstruction computer available on an MRI scanner with full user control. This scanner will provide a large range of benefits for our users, including but not limited to: improved signal to noise ratio (SNR) for all applications due o reduced noise in the digital receive system, which can be used for better detection of small signals, finer spatial resolution, and/or faster scans. SNR is further increased for DTI scans due to shorter echo time (TE) attainable with higher gradient strength (shorter diffusion time) and slew rate (shorter readout time). The availability of 128 receive channels provides a future path to high-end "connectome-type" RF hardware. The first commercially available 64-channel coil is expected to provide modestly improved SNR compared to 32-channel as well as an improved g-factor for parallel imaging, especially for controlled aliasing in SMS/MB imaging. Improved frequency stability compared to our current system will provide benefits for a) improved signal intensity stability for dynamic scans; b) absence of spatial image drift under high duty cycle gradient use such as in diffusion spectrum imaging (DSI) with many orientations and strong diffusion weighting; c) improved spectral editing with selective pulse excitation; d) improved CEST-MRI frequency referencing. Finally, user control of the reconstruction computer allows on- scanner processing of HCP-type acquisition sequences and real-time motion-correction algorithms.