The scientists say they could fairly accurately identify Alzheimer's disease and frontotemporal lobar degeneration without having to carry out invasive tests, such as a lumbar puncture, which involves sticking a needle into the spine. At the moment, diagnosing dementia is a struggle for doctors, which often results in delayed treatment. Invasive tests can help, but patients find them unpleasant.
Although their underlying disease processes are quite different, FTLD (frontotemporal lobar degeneration) and Alzheimer's disease can frequently share the same symptoms, making it hard for experts to make an accurate diagnosis.
Patients with Alzheimer's or FTLD both experience confusion and forgetfulness - their diseases/conditions can affect their emotions, behavior and personalities.
Duke University researchers recently found that by combining the results of three tests, doctors could more accurately diagnose Alzheimer's disease. The tests included MRI, fluorine 18 fluorodeoxyglucose positron emission tomography (FDG-PET), and cerebrospinal fluid analysis (lumbar puncture).
Finnish researchers developed a software tool that could reduce the average time to reach a diagnosis of Alzheimer's from 20 months to 10 months.
Study author Corey McMillan, PhD, said:
"Diagnosis can be challenging. If the clinical symptoms and routine brain MR are equal, an expensive positron emission tomography (PET) scan might be needed. Or, a lumbar puncture, which involves inserting a needle into the spine, would be needed to help make the diagnosis.
Analysis of the cerebrospinal fluid gives us reliable diagnostic information, but this is not something patients look forward to and is also expensive. Using this new MRI method is less expensive and definitely less invasive."
McMillan and team carried out a study involving 185 participants. They had all been diagnosed with a neurodegenerative disease which indicated either FTLD or Alzheimer's. They underwent a high resolution MRI scan as well as a lumbar puncture. Diagnosis was confirmed in 32 of the participants either by autopsy or by determining that they had a genetic mutation linked with either FTLD or Alzheimer's.
The team wanted to determine whether they could dispense with the lumbar puncture altogether and predict brain protein levels by using just MRI brain scans.
The MRI scans were used to predict the ratio of two biomarkers of FTLD or Alzheimer's - the proteins tau and beta-amyloid - in the lumbar punctures (cerebrospinal fluid).
MRI scans as accurate as lumbar punctures in identifying Alzheimer's or FTLDThey found that by studying the structural brain patterns - the density of gray matter - on the MRI scans, their predictions were 75% accurate when confirming diagnosis with people who had pathology-confirmed diagnoses and those with biomarker levels retrieved from lumbar punctures - this shows that the new MRI use is as accurate as lumbar puncture methods.
"Developing a new method for diagnosis is important because potential treatments target the underlying abnormal proteins, so we need to know which disease to treat. This could be used as a screening method and any borderline cases could follow up with the lumbar puncture or PET scan.
This method would also be helpful in clinical trials where it may be important to monitor these biomarkers repeatedly over time to determine whether a treatment was working, and it would be much less invasive than repeated lumbar punctures."
A study published this month found that globally, deaths from Alzheimer's and other dementia have risen more than three-fold over the last three decades.
Written by Christian Nordqvist