Breaking the Barriers to Microscale fMRI - SUMMARY
The goal of this proposal is to develop technology that is both novel and disruptive in order to achieve
anatomical quality, dynamic B0 corrected, whole brain, microscale (≤ 500 µm isotropic) fMRI. Our Brain
Initiative work thus far has demonstrated that, with the significant SNR gains of MR Corticography and SLIDER
technologies, ultra-high 500 µm resolution fMRI is feasible at 7T. However, significant barriers remain that
make microscale imaging of the whole brain extremely challenging, if not impossible. Current fMRI technology
relies on gradient-echo EPI which, especially at higher field strengths and resolutions, suffers from static B0
signal dropout, dynamic B0 distortions, T2* decay related blurring and large vein bias, which together limit our
ability to acquire true, whole brain, microscale resolution fMRI. Furthermore, even with advanced acceleration
techniques, scanning the entire brain at microscale resolution currently requires unacceptably long repetition
times (TR >> 3 s).
To address these limitations, we propose the development and integration of several key, novel
technologies. StImulus-Locked K-Space (SILK) fMRI technology, which we recently developed, overcomes the
spatial-temporal resolution tradeoff and provides anatomical quality, task-based, fMRI. By synergistically
combining SILK fMRI with cutting-edge commercially available technology for prospective and passive motion
mitigation (i.e. technologies offered by Kineticor and Caseforge) as well as for navigator based dynamic B0
correction (i.e. technologies offered by Siemens and MGH) we will achieve transformative advances in our
ability study both the microscale structure and function across the human brain. Importantly, because SILK
fMRI is based on the 3D GRE FLASH pulse sequence, SILK images can also serve as ground truth,
susceptibility weighted structural images capable of differentiating laminar organization as well as sources of
large vein bias. The dual anatomical/functional nature of SILK fMRI data is a disruptive paradigm shift that will
enable information rich, co-registration free, study of the brain at much higher fidelity and resolution than
current technology allows.
An additional advantage of the proposed technologies is that they are easily integrated into currently
existing 7T MRI scanners and therefore can be rapidly disseminated to both clinical and neuroscience imaging
research centers. Successful execution of this project would also greatly augment our ongoing Brain Initiative
studies aimed at improving localization and mapping of neuronal circuitry in the brains of both healthy and
patient populations.