Ultra-high resolution blood volume fMRI and BOLD fMRI in humans at 9.4 T: Capabilities and challenges

Laurentius Huber; Desmond H Y Tse; Christopher J Wiggins; Kâmil Uludağ; Sriranga Kashyap; David C Jangraw; Peter A Bandettini; Benedikt A Poser; Dimo Ivanov

doi:10.1016/j.neuroimage.2018.06.025

Ultra-high resolution blood volume fMRI and BOLD fMRI in humans at 9.4 T: Capabilities and challenges

Neuroimage. 2018 Sep:178:769-779. doi: 10.1016/j.neuroimage.2018.06.025. Epub 2018 Jun 8.

Authors

Laurentius Huber¹, Desmond H Y Tse², Christopher J Wiggins³, Kâmil Uludağ⁴, Sriranga Kashyap⁴, David C Jangraw⁵, Peter A Bandettini⁶, Benedikt A Poser⁴, Dimo Ivanov⁴

Affiliations

¹ Section on Functional Imaging Methods, Laboratory of Brain and Cognition, NIMH, NIH, Bethesda, MD, USA. Electronic address: Laurentius.Huber@nih.gov.
² Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands; Centre for Advanced Imaging, University of Queensland, Australia.
³ Scannexus BV, Maastricht, The Netherlands.
⁴ Maastricht Brain Imaging Center, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands.
⁵ Section on Functional Imaging Methods, Laboratory of Brain and Cognition, NIMH, NIH, Bethesda, MD, USA.
⁶ Section on Functional Imaging Methods, Laboratory of Brain and Cognition, NIMH, NIH, Bethesda, MD, USA; FMRIF, NIMH, NIH, Bethesda, MD, USA.

Abstract

Functional mapping of cerebral blood volume (CBV) changes has the potential to reveal brain activity with high localization specificity at the level of cortical layers and columns. Non-invasive CBV imaging using Vascular Space Occupancy (VASO) at ultra-high magnetic field strengths promises high spatial specificity but poses unique challenges in human applications. As such, 9.4 T B₁⁺ and B₀ inhomogeneities limit efficient blood tagging, while the specific absorption rate (SAR) constraints limit the application of VASO-specific RF pulses. Moreover, short T₂^* values at 9.4 T require short readout duration, and long T₁ values at 9.4 T can cause blood-inflow contaminations. In this study, we investigated the applicability of layer-dependent CBV-fMRI at 9.4 T in humans. We addressed the aforementioned challenges by combining multiple technical advancements: temporally alternating pTx B₁⁺ shimming parameters, advanced adiabatic RF-pulses, 3D-EPI signal readout, optimized GRAPPA acquisition and reconstruction, and stability-optimized RF channel combination. We found that a combination of suitable advanced methodology alleviates the challenges and potential artifacts, and that VASO fMRI provides reliable measures of CBV change across cortical layers in humans at 9.4 T. The localization specificity of CBV-fMRI, combined with the high sensitivity of 9.4 T, makes this method an important tool for future studies investigating cortical micro-circuitry in humans.

Trial registration: ClinicalTrials.gov NCT00001360.

Keywords: 3D-EPI; 9.4 T tesla MRI; Cerebral blood volume; Layer-dependent fMRI; SS-SI VASO; STARC; Vascular space occupancy; pTx.

Published by Elsevier Inc.

Publication types

Research Support, N.I.H., Intramural
Research Support, Non-U.S. Gov't

MeSH terms

Brain / blood supply*
Brain Mapping / methods*
Cerebral Blood Volume / physiology*
Humans
Image Processing, Computer-Assisted / methods*
Magnetic Resonance Imaging / methods*

Associated data

ClinicalTrials.gov/NCT00001360

Abstract

Publication types

MeSH terms

Associated data

Grants and funding