A new study published in Human Brain Mapping further validates MR’s role in diagnosing Alzheimer’s disease before symptoms are present.

If the medical field can diagnose the disease in its earliest stage, patients could be treated before irreversible brain damage or mental decline occur, according to the Alzheimer’s Association.

"I hope this study will encourage researchers to use advanced imaging techniques to study the early preclinical phase of [Alzheimer's], and to evaluate the impact of early interventions to delay or prevent the progression of the disease," Christine Tardif, assistant professor at the McConnell Brain Imaging Centre of the Montreal Neurological Institute and Hospital, told HCB News.
Tardif and her team at McGill University and McGill-affiliated health institutes studied 88 patients with a hereditary risk of Alzheimer’s, but no cognitive signs of the disease. Each of them underwent both MR exams to determine brain volume, and lumbar puncture to test levels of amyloid-Beta and tau proteins in the brain.

They then used statistical models and found that high levels of amyloid-Beta and tau are associated with smaller volumes and intensity profiles of specific regions of the hippocampal circuit. That’s less likely to occur if there is an accumulation of only one of the proteins.

It’s already known among the medical community that the hippocampus atrophies and loses volume in some Alzheimer’s patients years before patients show signs of cognitive decline.

The research team concluded that these biomarkers may one day enable physicians to diagnose patients at risk of Alzheimer’s with only MR imaging. That would eliminate the need for lumbar puncture, which is an invasive procedure to extract cerebrospinal fluid.

The biomarkers also have the potential to be used to test the effectiveness of Alzheimer’s drugs in clinical trials.

A team of researchers at Massachusetts General Hospital also investigated the use of MR to spot those in early, presymptomatic stages of Alzheimer’s. In October 2016, they reported that MR was able to determine that those with the disease had asymmetrical brain structures in the left and right sides of the brain.

Tardif believes that MR will be one of the tools used to identify individuals at risk, in combination with family history, genetics and other factors.

"The improvement in image quality and analysis tools will enhance our sensitivity to subtle changes in brain structure before clinical symptoms appear," she said. "However, we still don't fully understand the relationship between the pathophysiology and changes in brain volume detected using MR."

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