MRI is a proven non-invasive technique to make functional MRI (fMRI) by measuring changes in "blood oxygen level dependent" (BOLD) contrast in different regions of the brain resulting from the neurovascular coupling of neuronal activity. Echo planar imaging (EPI) is the most widely used fMRI pulse sequence, due to its speed and BOLD contrast, however EPI has relatively poor image quality due to distortions and signal missing from brain regions of high susceptibility near bone and air interfaces. In high spatial resolution (sub-millimeter) fMRI at 7T to explore the functional organization of the cortex, EPI is limited to single 2D image slice that cannot reveal the true 3D distribution of neuronal activity. We are proposing of the development of a family of highly efficient 3D fMRI pulse sequences which obtain sub-second 3D images of the brain, optimized for BOLD contrast in fMRI. The sequences will utilize gradient-and-spin-echo (GRASE) pulse sequence which is hybridized and modified to obtain BOLD contrast in high spatial resolution and minimal artifacts. The new 3D fMRI sequences will be designed and implemented to reduce or eliminate the susceptibility related artifacts of distortion and signal loss in EPI. The availability of these 3D fMRI pulse sequences will give researchers and clinicians the capability of performing fMRI of the brain with improvements over current 2D fMRI methodology. The sequence will be designed and implemented on a 1.5T MR scanner. The new sequences will be ported to 3T and 7T high field scanners at University of California Berkeley, University of Minnesota and UCSF where the new imaging technology will undergo further optimization and testing in neuroscience studies.
Public Health Relevance: Functional MRI (fMRI) is a widely used method to study the brain while it is performing thinking tasks and to map out regions of brain activity. We are proposing a sub-second 3D imaging technology to be supplement or replace the current use of sub-second 2D imaging for fMRI. The 3D fMRI will be useful for revealing the basic organization of the brain's activity which could lead to new discoveries of how the brain works. The resulting measurements obtained in the brain with 3D fMRI will be useful for studies of neurodegenerative diseases including Alzheimer's disease, drug trials and for evaluating people with stroke and cerebrovascular diseases.
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