TRD3 Addressing biological barriers in in vivo human brain MRI acquisitions Abstract In this project, we propose a program of bioengineering development to improve human functional and anatomical MRI at its acquisition stage.
We aim to bridge the macro and micro scales of brain architecture by improving the spatio-temporal resolution of fMRI down to its biological limits. The barriers we face in acquisition encoding and then again in the ability of MRI to perform anatomical imaging at the meso scale (500 um or less) and finally the spatial fidelity of fMRI maps themselves are primarily biological. Firstly, we impact MRI encoding broadly by focusing on methods to address the Peripheral Nerve Stimulation (PNS) barrier in application of fast gradient coils. We will improve gradient coil technology through utilizing a detailed peripheral nerve stimulation model to predict nerve stimulation and optimize reduction strategies.
In Aim 2 we address the confounds of respiratory and patient motion in anatomical imaging through motion robust image reconstruction of anatomical MR images using a data-consistency driven approach. We jointly estimate biological nuisance modulations from respiration and patient motion within the multi-channel kspace data. Successful joint estimate of the image and the nuisance variables within a comprehensive forward model effectively removes these confounds from the image yielding a motion and respiratory robust acquisition. Finally, in aim 3 we develop methods to address spatial resolution limits imposed on fMRI by large vasculature by predicting and removing them from the activation maps on the flattened cortical surface by models incorporating prior knowledge from high resolution vascular maps. Overall, our tools will broadly advance the study of human brain circuits at the mesoscopic scale while retaining the whole- brain and non-invasive features of MRI.
TRD 3 Addressing biological barriers in in vivo human brain MRI acquisitions As engineering obstacles to producing better and better images of the living human brain with MRI are solved, the remaining barriers are progressively becoming biological limits. This necessitates a new approach to optimizing how the scanner takes its data and must now include a firm understanding of how the biology and biological factors, such as the presence of blood vessels, patient breathing, or other motion, alters images. We must also increasingly consider how the nerves in the body respond to the magnetic fields used in MRI. In this bioengineering program we will change the way we optimize MRI imaging to account for these issues, ultimately providing higher fidelity images of the human brain in health and disease.