Measuring brain integrity using MRI: A novel biomarker for Alzheimer’s disease using T2 relaxometry

Speaker: Dr. Alfie Wearn, Ph.D.

Postdoctoral Research Associate, University of Bristol, UK

Talk Abstract: In neurodegenerative diseases, such as Alzheimer’s disease, it is important to identify damage to the brain as quickly as possible before irreversible damage has occurred. My work shows that magnetic resonance imaging (MRI) may be even better at detecting damage to the brain than we thought - if we only look at the data in the right way.

Prior to significant brain tissue atrophy, several microstructural changes take place as a result of Alzheimer’s pathology. These include deposition of amyloid, tau and iron, as well as altered water homeostasis in tissue and some cell death. T2 relaxation time, a quantitative MRI measure, is sensitive to these changes and may be a useful non-invasive, early marker of tissue integrity which could predict conversion to dementia. I propose that different microstructural changes affect T2 in opposing ways, such that average ‘midpoint’ measures of T2 are less sensitive than measuring distribution width (heterogeneity). T2 heterogeneity in the brain may present a sensitive early marker of AD pathology.

In this talk I will summarize findings from my recently completed PhD studies, in which I explored the clinical utility of T2 heterogeneity in older people with and without cognitive impairment. I will present a model of early changes in T2 in the medial temporal lobe that considers the competing effects of factors that both increase and decrease T2.