Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Amyloid is a less accurate marker for measuring severity, progression of Alzheimer's

07.08.2019

Researchers find fluorodeoxyglucose (FDG) PET is a better indicator of cognitive performance when compared to PET scans that detect amyloid protein

While the presence of beta-amyloid plaques in the brain may be a hallmark of Alzheimer's disease, giving patients an amyloid PET scan is not an effective method for measuring their cognitive function, according to a new study from researchers in the Perelman School of Medicine at the University of Pennsylvania and Thomas Jefferson University.


PET imaging using the radiotracers FDG and florbetapir to quantify cognitive decline in patients with Alzheimer's disease (AD), mild cognitive impairment (MCI), and healthy controls

Credit: Penn Medicine

The researchers concluded that fluorodeoxyglucose (FDG) PET, which measures the brain's glucose consumption as a marker of neural activity, is a stronger approach for assessing the progression and severity of Alzheimer's and mild cognitive impairment (MCI) as compared to florbetapir-PET scans, which reveal amyloid protein deposits in the brain.

This suggests that FDG-PET is also a better means for determining the effectiveness of Alzheimer's therapies, as well as tracking patients' disease advancement, in both clinical and research settings. Results of this study are detailed in the August issue of the Journal of Alzheimer's Disease.

"Both florbetapir-PET and FDG-PET are approved diagnostic methods for Alzheimer's disease, and both appear to be effective in indicating some sort of cognitive impairment. However, we have now shown that FDG-PET is significantly more precise in clinical studies, and it is also available for routine use with modest costs," said the study's co-principal investigator Abass Alavi, MD, PhD, a professor of Radiology at Penn. "Our results support the notion that amyloid imaging does not reflect levels of brain function, and therefore it may be of limited value for assessing patients with cognitive decline."

Alzheimer's disease, the most common cause of dementia, is the sixth leading cause of death in the United States, affecting up to 5.8 million Americans currently. As clinicians aim to spot and treat the symptoms of dementia in its earliest stages, PET plays an increasingly pivotal role in diagnosing and monitoring Alzheimer's disease, as well as MCI, a condition that often precedes dementia.

Two of the most significant biomarkers found in Alzheimer's are decreased glucose uptake and the accumulation of amyloid plaques in the brain. PET scans use different radioactive drugs, called radiotracers, to measure these biomarkers within the brain tissue of patients with cognitive impairment. FDG-PET is one of the most commonly used imaging techniques to diagnose Alzheimer's. However, in recent years, several other radiotracers, such as florbetapir, have been developed to detect the deposition of amyloid plaques.

Recently, the effectiveness of amyloid imaging as a strategy for monitoring dementia symptoms has been called into question. While the presence of amyloid plaques in the brain is considered as being characteristic of Alzheimer's, some studies have shown that large amounts of amyloid plaques were present in healthy, non-demented individuals. Conversely, recent clinical trials have shown that the intended removal of amyloid from the brains of patients with Alzheimer's disease led to no change in, or even worsened, cognitive performance.

In this study, the researchers evaluated 63 individuals, including 19 with clinically diagnosed Alzheimer's disease, 23 with MCI, and 21 healthy individuals. The study participants underwent both FDG- and florbetapir-PET imaging. They were then assessed with a Mini Mental Status Examination (MMSE), a widely used diagnostic test for detecting and assessing the severity of cognitive impairment. The researchers used a novel "global quantification approach" to generate data from five different regions of the brain, which were correlated with the results from the MMSE scores.

The study revealed that both FDG- and florbetapir-PET scans are able to effectively discriminate the individuals with dementia from the healthy control group. However, when compared with the MMSE scores, the correlation between low cognitive performance and high levels of amyloid was significantly weaker than the correlation between FDG and low cognitive performance for all groups included in the study. This suggests that FDG-PET is a more sensitive indicator of cognitive decline.

"Amyloid imaging has a value in diagnosing or ruling out Alzheimer's disease, but it's a bit like all or nothing. Our study shows that it can reveal disease, but you wouldn't be able to differentiate between someone who had very mild or very severe symptoms," said co-principal investigator Andrew Newberg, MD, a professor of Radiology at Thomas Jefferson University, who added that these findings have important implications for clinical research.

"In a clinical drug trial, for example, it may be more relevant to do an FDG-PET scan, rather than using amyloid as a marker, to find out whether the therapy is working," Newberg said.

While FDG-PET may not be a perfect diagnostic tool, the study confirms that currently it is the best available method for monitoring symptoms of dementia, according to Alavi.

"Right now, FDG is king when it comes to looking at brain function, not only in Alzheimer's disease, but also diseases like vascular dementia and cancer," Alavi said.

###

Additional Penn Medicine authors include Jonah Peter, Sara Pourhassan Shamchi, and Thomas J. Werner, all in the department of Radiology. Thomas Jefferson University authors include Mohsen Khosravi, Nancy A. Wintering, and Mijail Serruya.

Lauren Ingeno | EurekAlert!
Further information:
https://www.pennmedicine.org/news/news-releases/2019/august/measuring-brains-amyloid-buildup-less-effective-alzehimers-disease-compared-imaging-methods
http://dx.doi.org/10.3233/JAD-190220

More articles from Medical Engineering:

nachricht Stanford develops wireless sensors that stick to the skin to track our health
16.08.2019 | Stanford University

nachricht Operating on Hips in a Virtual Operating Room
13.08.2019 | Technische Universität Chemnitz

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A miniature stretchable pump for the next generation of soft robots

Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.

Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...

Im Focus: Vehicle Emissions: New sensor technology to improve air quality in cities

Researchers at TU Graz are working together with European partners on new possibilities of measuring vehicle emissions.

Today, air pollution is one of the biggest challenges facing European cities. As part of the Horizon 2020 research project CARES (City Air Remote Emission...

Im Focus: Self healing robots that "feel pain"

Over the next three years, researchers from the Vrije Universiteit Brussel, University of Cambridge, École Supérieure de Physique et de Chimie Industrielles de la ville de Paris (ESPCI-Paris) and Empa will be working together with the Dutch Polymer manufacturer SupraPolix on the next generation of robots: (soft) robots that ‘feel pain’ and heal themselves. The partners can count on 3 million Euro in support from the European Commission.

Soon robots will not only be found in factories and laboratories, but will be assisting us in our immediate environment. They will help us in the household, to...

Im Focus: Scientists create the world's thinnest gold

Scientists at the University of Leeds have created a new form of gold which is just two atoms thick - the thinnest unsupported gold ever created.

The researchers measured the thickness of the gold to be 0.47 nanometres - that is one million times thinner than a human finger nail. The material is regarded...

Im Focus: Study on attosecond timescale casts new light on electron dynamics in transition metals

An international team of scientists involving the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) in Hamburg has unraveled the light-induced electron-localization dynamics in transition metals at the attosecond timescale. The team investigated for the first time the many-body electron dynamics in transition metals before thermalization sets in. Their work has now appeared in Nature Physics.

The researchers from ETH Zurich (Switzerland), the MPSD (Germany), the Center for Computational Sciences of University of Tsukuba (Japan) and the Center for...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The power of thought – the key to success: CYBATHLON BCI Series 2019

16.08.2019 | Event News

4th Hybrid Materials and Structures 2020 28 - 29 April 2020, Karlsruhe, Germany

14.08.2019 | Event News

What will the digital city of the future look like? City Science Summit on 1st and 2nd October 2019 in Hamburg

12.08.2019 | Event News

 
Latest News

Working out why plants get sick

16.08.2019 | Life Sciences

Newfound superconductor material could be the 'silicon of quantum computers'

16.08.2019 | Physics and Astronomy

Stanford develops wireless sensors that stick to the skin to track our health

16.08.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>