Image of Dr. David Mikulis
Krembil neuroradiologist Dr. David Mikulis’ research uses MRI technology to observe the effects of blood flow on connecting fibers in the brain. (Photo: UHN)

Dr. David Mikulis, neuroradiologist with the Joint Department of Medical Imaging at the Krembil Neuroscience Centre, has received a grant to investigate one of the hottest topics in the field of neuroradiology: the imaging of dementia.

The prestigious grant from the Foundation of the American Society of Neuroradiology (ASNR) will allow Dr. Mikulis to study cerebral vascular function in search of an imaging biomarker that can help with the early detection of Alzheimer's disease.

"In our preliminary studies, patients with early cognitive impairment, years before the development of Alzheimer's disease, have slower opening of their brain blood vessels that correlates directly with how well the brain is functioning," said Dr. Mikulis, who is also a senior scientist at the Krembil Research Institute.

"We think this could become a marker of an early stage of the disease."

Contributing factors to Alzheimer's disease

Obesity, high blood pressure, smoking, diabetes, inactivity and elevated blood cholesterol levels are all vascular risk factors that can damage blood vessels, subsequently reducing their ability to properly adjust blood flow in the brain. When this happens, the coupling of brain blood flow to brain activity is impaired. This leaves neurons starved for blood.

"This is one of the features that we believe contributes to Alzheimer's disease," says Dr. Mikulis, whose research uses brain imaging, specifically MRI (Magnetic Resonance Imaging), to observe the effects of blood flow on connecting fibers in the brain.

"Think of a plant in the summer. If it doesn't get enough water it may not die, but instead, it starts to wither and shrivel," says Dr. Mikulis.

"That's what we think is happening to the complexity of the brain connections leading to a decrease in cognitive function. The brain simply isn't working as well as it could."

Benefits of early detection

Dr. Mikulis also theorizes that inadequate blood flow can lead to a buildup of amyloid protein in the brain. "This is nasty stuff and you don't want it to accumulate. It kills neurons eventually leading to Alzheimer's disease."

If these vascular problems can be detected earlier, Dr. Mikulis believes it might be possible to devise a treatment that can delay or stop the progression of the disease before it is too late.

The ASNR grant will allow Dr. Mikulis to study vascular function in search of an imaging biomarker for two years and will include contributions by researchers at the University of Toronto and John Hopkins University.​

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