Parallel MRI for High Field Neuroimaging

描述(申请人提供)：这是研究资助R01DA019912“用于高场神经成像的并行磁共振成像”研究项目的续展，用于开发快速、无伪影的功能磁共振成像(FMRI)技术。在前一个供资期间，开发了许多方法来使用“并行传输”(PTX)和“定制射频”(TRF)脉冲来校正图像伪影。这些伪影包括射频场(B1+)不均匀和磁化率伪影(B0不均匀)。B1+的不均一性会在图像中产生很大的强度差异，而B0的不均质性会产生大量的信号空洞，从而掩盖了许多大脑区域，这些区域对于了解大脑中的疾病包括成瘾障碍至关重要。近年来，多层同时成像技术已被证明是一种很有前途的超高速功能磁共振成像技术。在使用多个接收器线圈的重建过程中，短信息系统成像可激发多个重叠切片。短信成像对于包括功能磁共振成像在内的许多应用都具有重要意义，因为它可以将采集速度提高4到8个数量级。尽管短信息成像越来越流行，但在改进短信息射频脉冲激励、将其扩展到PTX和非笛卡尔螺旋数据采集方面所做的工作很少。改进的脉冲设计和PTX将允许减少B1+和B0不均匀的短消息刺激。螺旋成像具有高效的梯度使用，允许更短的采集时间和进一步提高采集速度。此次续订将重点介绍3T短信成像的这些创新。PI组建了一支由国际知名科学家组成的团队，其中包括马萨诸塞州总医院的Lawrence Wald博士，他是PTX线圈设计和短信成像方面的世界专家，以及Vanderbilt大学的William Grissom博士，他是PTX和RF脉冲设计的顶级研究员。我们将追求以下具体目标：(1)开发用于PTX的短信激励；(2)开发补偿B1+和B0不均质性的短信TRF脉冲；(3)开发用于超快短信成像的非笛卡尔螺旋采集和重建；以及(4)在对照受试者中使用功能磁共振来验证方法。

DESCRIPTION (provided by applicant): This is a renewal of a Research Project Grant R01DA019912 "Parallel MRI for High Field Neuroimaging" for the development of techniques for rapid, artifact free functional MRI (fMRI). During the previous funding period numerous methods were developed for correcting image artifacts using "parallel transmission" (PTX) and "tailored RF" (TRF) pulses. These artifacts include RF field (B1+) inhomogeneity and susceptibility artifacts (B0 inhomogeneity). B1+ inhomogeneity produces large intensity variations in images and B0 inhomogeneity creates large signal voids that obscure many brain regions crucial to understanding disease in the brain including addictive disorders. Recently Simultaneous Multi-Slice (SMS) imaging has been shown to be a promising technique for ultra-fast fMRI. SMS imaging excites multiple overlapping slices that are unfolded during reconstruction using multiple receiver coils. SMS imaging is significant for numerous applications including fMRI because it allows for increased acquisition speed on the order of four to eight. Although SMS imaging is gaining popularity, there has been little work done on improving SMS RF pulse excitations, extending it to PTX, and to non-Cartesian spiral data acquisitions. Improved pulse designs and PTX will allow for SMS excitations with reduced B1+ and B0 inhomogeneity. Spiral imaging has a highly efficient gradient usage allowing for shorter acquisition times and further increases in acquisition speed. This renewal will focus on these innovations to SMS imaging at 3T. The PI has assembled a team of internationally recognized scientists including Dr. Lawrence Wald at Massachusetts General Hospital, who is a world expert in PTX coil design and SMS imaging, and Dr. William Grissom at Vanderbilt University, who is a top researcher in PTX and RF pulse design. We will pursue the following Specific Aims: (1) Develop SMS excitations for PTX; (2) develop SMS TRF pulses that compensate for B1+ and B0 inhomogeneity; (3) develop non-Cartesian spiral acquisitions and reconstructions for ultra-fast SMS imaging; and (4) validate the methods with fMRI in control subjects.