Design and construction of an ultrasound array for high-resolution brain imaging

Abstract

The goal of my project is to develop a new ultrasound neuroimaging modality to mitigate the adverse effects that brain injury has on our population. Acquired brain injury is the leading cause of death and disability in Western countries. Immediate imaging is key to survival and currently, state of the art systems based on X-ray and MRI, are not portable and do not allow images to be acquired at the site of injury.

Conventional ultrasound is a safe imaging modality used to monitor brain injury. It is inexpensive and portable, but it lacks the capacity to produce structural images of the entire brain. Ultrasound full-waveform inversion (FWI) is a novel medical imaging modality with the potential to image the brain in high resolution. However, a device to implement this technology in the brain does not yet exist.

In this thesis I explore the development of the first brain acquisition device capable of producing fast and high-accuracy brain images. To accomplish this, I investigate different ultrasound transducer types and array configurations, both in silico and in vitro, to determine the best design for their application to brain imaging with FWI, an imaging technique developed in the field of seismology.

The first part of my thesis presents early proof-of-concept experiments using human skulls and 2D imaging experiments with a brain phantom. It then progresses to explore the optimal array design for 3D in-vivo brain imaging. My work corroborates the potential of ultrasound FWI to image the human brain and provides the background knowledge required to develop a clinical prototype for in-vivo imaging in humans.