Alzheimer’s disease has always been diagnosed based on symptoms. You get lost driving home from the store. You can’t remember your next door neighbor’s name. You have trouble with a simple math problem. These unmistakable signs only appear late in the course of the disease, long after the brain is significantly damaged. An MRI brain scan hadn’t proven useful for early diagnosis of Alzheimer’s – until now.
New research from Washington University School of Medicine in St. Louis shows that a novel MRI approach can identify brain cell damage in people in early stages of Alzheimer’s – before tissue shrinkage is visible on traditional MRI scans and before cognitive symptoms arise.
Alzheimer’s disease develops slowly over the course of two decades or more before symptoms arise. While traditional MRI is capable of showing where damaged areas of the brain have decreased in volume, this new MRI technique (called the quantitative Gradient Echo or qGRE) goes a step further, detecting the loss of neurons that precedes brain shrinkage and cognitive decline. Researchers say this approach could be a new way to use MRI to diagnose people with Alzheimer’s before they develop symptoms.
While Alzheimer’s researchers continue to pursue drug treatments for the disease, most agree that successful treatment will hinge on early detection and on finding ways to head off brain damage before later stages of Alzheimer’s.
While PET scans and spinal taps continue to play important roles in Alzheimer’s research, both have limitations that prevent their widespread use as a screening tool for early signs of the disease. PET brain scans are still the gold standard for detecting signs of Alzheimer’s, but the machines are expensive and seldom available for routine patient diagnosis, much less widespread clinical screening. PET scans also require the injection of a radioactive tracer for brain imaging.
Another promising option for Alzheimer’s screening – also under development at Washington University – is a noninvasive, relatively inexpensive blood test that has proven to be highly accurate in detecting early signs of Alzheimer’s disease. A commercial version of the blood test recently became available to doctors in the United States and Europe, but is not yet covered by health insurance.
Dmitriy Yablonskiy, PhD, a professor of radiology at the university’s Mallinckrodt Institute of Radiology is the senior author of the study. He and colleagues are among the many researchers now pursuing a low-cost, easily accessible test for Alzheimer’s as an alternative to the expensive PET brain scans and invasive spinal taps now used in research settings to assess the presence and progression of the disease.
Such a test, especially one that can identify people at very early stages of disease, would provide a huge boost to Alzheimer’s research.
“Our qGRE test offers great potential as an early diagnostic tool for the preclinical stage of Alzheimer’s disease, thus providing a large window for therapeutic intervention,” Yablonskiy said. “It also has great potential as a noninvasive MRI technique available for the widespread screening that is necessary to get people with early Alzheimer’s into clinical drug trials – thus spurring the development of new treatments.”
Originally published by Washington University School of Medicine in St. Louis