Together with MIT graduate student Daisy Chien, and colleagues Richard Buxton, Tom Brady and Bruce Rosen he was one of the earliest entrants in the field of brain diffusion imaging, which itself was opened by the pioneering experiments of Denis Le Bihan.
[1] This anisotropy itself is the fundamental principle underlying the modern method of MRI tractography and structural connectomics (the in vivo visualization the axonal fibers that connect neurons in the brain) .
In technically demanding circumstances (a low field MRI using conventional imaging, located in a parking lot trailer nearby the MGH) they were the first to demonstrate in human subjects[2] the early drop in diffusivity seen in acute infarction in cats by Moseley.
The EPI method proved extremely powerful in the study of both perfusion and diffusion by allowing Kwong, and others, to evaluate dynamic changes in signal, such as the flow of blood labeled with injected magnetic contrast agents through the organ systems.
The landmark results of Belliveau, et al., in 1991,[5] using dynamic susceptibility contrast heralded the creation of a new field in functional activity mapping of the human brain using magnetic resonance imaging - fMRI.
Later groundbreaking experiments by Ogawa, et al., and by Turner had shown that oxygen depletion led to significant drops in MRI signal changes in large veins and the brain cortex itself, respectively, via a magnetic susceptibility mechanism analogous to that used by Belliveau with exogenous tracers, but in this case using deoxygenated blood itself as the contrast agent.
The first dynamic video images of human brain activity appeared first at a meeting of the Society for Magnetic Resonance in Medicine in August 1991 in San Francisco in a plenary session by colleague Tom Brady, and was subsequently published in 1992 in the Proceedings of the National Academy of Sciences.
This forms the basis of a second set of modern methods known now as arterial spin labeling, increasingly used when quantification of baseline and changing physiology is required.