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According to a new study, MRI brain tests could prove to be more effective than conventional clinical tests in predicting the risk of developing Alzheimer's disease.
Alzheimer's disease is a progressive and irreversible brain disorder that destroys memory and thinking skills – and the number of people diagnosed is rising.
But this remains elusive: the disease can not technically be diagnosed during life (only at an autopsy) and scientists have not been able to say for sure what a brain looks like to Alzheimer's disease.
Currently, physicians are able to rapidly detect approximately 70% of cases using cognitive measurement questionnaires and APOE4 gene testing, which is associated with 50% of Alzheimer's cases (but also detected in healthy people).
However, a new study, published today by a team from the University of Washington's Faculty of Medicine, has revealed revealing symptoms appearing on up to 95% of MRI scans of future patients with of Alzheimer's disease before the onset of the disease.
The small study of 61 patients at the University of Washington suggests a technique that, if successful, would be a better alternative to the current questionnaire-based screening method.
If the results can be replicated in a larger group (this study was conducted with 61 people), this could pave the way for the very first concrete screening technique for Alzheimer's disease, which is infecting more and more people at an alarming rate.
Although 70% seems to be a fairly high accuracy rate for current tests, Alzheimer's disease is becoming more commonplace. Missing 30% of cases is a huge margin of error in the grand scheme of things.
The new MRI exams in Washington, using diffusion tensor imaging (DTI) to assess the white matter state of the brain, revealed an accuracy of 89 to 95%.
"Alzheimer's disease is the most common cause of dementia in the world and is expected to increase globally, and particularly in the United States, as the population ages," Dr. Cyrus Raji, lead author of the study, assistant professor of radiology at the Mallinckrodt Institute of Radiology Institute, said.
"As we develop new drug therapies and study them during clinical trials, we need to identify the people who will benefit from these drugs earlier during the course of the disease.
"With DTI, you watch the movement of water molecules along the white lanes, the telephone cables of the brain.
"When these pathways are not well connected, cognitive problems can result."
He added that the DTI provided different measures of white matter integrity, including fractional anisotropy (AF), a measure of how water molecules move along the white matter pathways.
A higher FA value indicates that the water is moving more neatly along the pathways, while a low value means that the pathways are probably damaged.
For the new study, Dr. Raji and his colleagues set out to quantify the differences in ITDs in people with normal cognitive decline or mild cognitive impairment to Alzheimer's dementia compared to controls not developing dementia.
They performed DTI brain tests on 61 people from the Alzheimer's Disease Neuroimaging Initiative, a major study focused on disease progression.
About half of the patients developed Alzheimer's disease and the DTI identified "quantifiable differences" in the brains of these patients.
People who developed the disease had a lower AF than other patients, suggesting damage to the white matter. They also had statistically significant reductions in some leaflets of the frontal white matter.
Dr. Raji said, "The DTI is very well behaved in relation to other clinical measures.
"By using the values of AF and other overall measures associated with the integrity of the white matter, we were able to obtain an accuracy of 89% to predict who was going develop Alzheimer's disease. The mini-mental state examination and the APOE4 gene test have accuracy rates of about 70 to 71%. & # 39;
The researchers conducted a more detailed analysis of the white matter pathways in approximately 40 study participants.
Dr. Raji said that among these patients, the technique reached an accuracy of 95%.
He added that many people were already receiving an MRI as part of their care. Therefore, the DTI could add a "significant value" to the exam without significantly increasing costs.
Dr. Raji said that MRI measurements of white matter integrity could speed up interventions that slow the progression of the disease or even delay its onset.
He added: "Research shows that the risk of Alzheimer's disease can be reduced by tackling modifiable risk factors such as obesity and diabetes.
"With early detection, we can implement lifestyle interventions and engage volunteers early in drug trials."
The results should be presented at the annual meeting of the North American Radiology Society (RSNA) in Chicago next week.
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