Parallel MRI for High Field Neuroimaging

描述（由申请人提供）：这是研究项目资助R01DA019912“用于高场神经成像的平行MRI”的更新，用于开发快速，无伪影的功能MRI （fMRI）技术。在之前的资助期间，开发了许多使用“平行传输”（PTX）和“定制射频”（TRF）脉冲校正图像伪影的方法。这些伪影包括射频场（B1+）不均匀性和磁化率伪影（B0不均匀性）。B1+的不均匀性会在图像中产生很大的强度变化，而B0的不均匀性会产生很大的信号空洞，从而模糊了许多对理解大脑疾病（包括成瘾性疾病）至关重要的大脑区域。近年来，同步多层成像（SMS）已被证明是一种很有前途的超快速功能磁共振成像技术。SMS成像激发多个重叠的切片，这些切片在使用多个接收器线圈重建期间展开。SMS成像对于包括fMRI在内的许多应用都很重要，因为它可以将采集速度提高4到8倍。虽然SMS成像越来越受欢迎，但在改进SMS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不均匀性的SMS激励。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。此次更新将重点关注3T短信成像的这些创新。PI汇集了国际知名的科学家团队，其中包括麻省总医院的Lawrence Wald博士，他是PTX线圈设计和SMS成像的世界专家，以及范德比尔特大学的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)为PTX开发SMS激励；(2)开发补偿B1+和B0不均匀性的SMS后机匣脉冲；(3)为超高速SMS成像开发非笛卡儿螺旋采集和重建；(4)用fMRI在对照对象上验证方法。

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.