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Amyloid PET Imaging Research Raises Possibilities for Earlier Dementia Diagnosis

Dr.

Dr. Francois Nicolas, Director of Neurology at GE Healthcare, and member of the Scientific Advisory Board of the Joint Program for Neurodegenerative Disease

World

World Alzheimer’s Month has become an annual event in which the campaign highlights the prospect of 682 million people living with dementia in the next 40 years

Currently,

Currently, AD is diagnosed through clinical examinations (medical history, mental status and cognitive testing and physical, psychiatric, and neurological exams and laboratory tests)

World Alzheimer’s Month has become an annual event in which the campaign aims not only to highlight the prospect of 682 million people living with dementia in the next 40 years* but also dispel the myths associated with dementia and the people who are affected by it. This stigma prevents people from acknowledging symptoms and obtaining the help they need.

As part of World Alzheimer’s Month, Dr. Francois Nicolas, Director of Neurology at GE Healthcare, and member of the Scientific Advisory Board of the Joint Program for Neurodegenerative Disease, talks about his hopes for the future as GE Healthcare continues research into the development of a portfolio of Positron Emission Tomography (PET) tracers. Dr Nicolas is also leading GE Healthcare’s long term effort to develop disease-oriented diagnostic tools for Alzheimer’s disease (AD).

It is only within the last 10-15 years that imaging for a host of neurodegenerative diseases has taken on a new level of clarity, detail, and quality. Healthcare providers have been able to combine the modalities of imaging such as MRI and PET with more traditional clinical diagnostic assessments of dementia to enable better, more informed patient diagnosis. 

“It must be stressed that imaging is not a definitive tool,” explained Dr. Nicolas. “It’s used more as an adjunct to other diagnostic information. The diagnostic process still remains dependent on the clinical spectrum, where a range of examinations are carried out in order to reach an informed conclusion.”

Currently, AD is diagnosed through clinical examinations (medical history, mental status and cognitive testing and physical, psychiatric, and neurological exams and laboratory tests). A definitive diagnosis can only be confirmed through histopathological identification of core features, including beta amyloid plaques and neurofibrillary tangles, in post-mortem brain samples. **

Non-invasive tests to detect these characteristics may not by themselves tell if someone has AD, but may be used to help rule out the disease at the point in time the test was performed.

The aim of GE Healthcare research is to enable earlier identification of AD pathophysiology, providing disease-oriented imaging tools to assist in the diagnosis and management of the disease. Dr. Nicolas noted an Alzheimer’s disease International report which reported only 20-50% of patients with the condition is diagnosed with Alzheimer’s disease. So potentially there are between 50-80% of patients, who are not diagnosed and whose condition may not be properly managed, either medically, socially or behaviourally. *** 

While great progress has been made, Dr. Nicolas acknowledges the challenges ahead. “Broadly speaking you have to aggregate a lot of information, including clinical, medical history, cognitive testing, blood testing, and results from imaging. The challenge extends to the different institutions and individuals all working on different IT systems and standards. What algorithms do you use to combine this information?”

Dr. Nicolas points to a project on which GE Healthcare is working which holds great potential in possibly achieving some much-needed value in the assessment of patients with cognitive disorders. Amyloid PET imaging, has only been clinically available since April 2012, when the U.S. Food and Drug Administration (FDA) approved the first radiopharmaceutical for brain amyloid PET imaging.

Amyloid (or beta amyloid) is a protein that builds up as deposits or plaques in the brain in Alzheimer’s patients. Previous methods of assessing the presence of amyloid could only be assessed with the help of a biopsy or post-mortem autopsy of the patient. 

Amyloid PET imaging is able to view the brain in vivo making an assessment of amyloid load in adults with cognitive impairment who are being evaluated for Alzheimer's disease. Detection of AD pathology in life subsequently raises the possibility of developing and assessing new treatment strategies.

“The main challenge is being able to verify and validate the fact that you’re seeing proteins in the images,” said Dr. Nicolas. “This is achieved by assessing the concordance of the imaging with what is discovered in the autopsy. GE Healthcare have been involved in a study to do just that enrolling end-of-life patients in the research, who have agreed to donate their brains for further study. It’s only within the last couple of years that Amyloid PET imaging has really come into its own.”

When asked about what the future might hold for the imaging, diagnosis, and treatment of neurodegenerative diseases, Dr. Nicolas was excited and enthusiastic about the potential of the work GE Healthcare is conducting.

“Patients will have access to more accurate diagnostic tests,” he added. “The healthcare policy and economic aspects will also gain prominence as it will be imperative to demonstrate value and better outcomes for patients to achieve broad acceptance of these technologies.”

Dr. Nicolas also predicted an increased link between the diagnostics and therapeutics, citing AD and other neurodegenerative diseases as an active field of research for pharmaceutical companies because of the unmet need and high prevalence of these conditions. Pharmaceutical companies are looking at targeted treatments assisted by PET imaging in order to tailor treatment to the individual who will benefit the most. 

“From a pharmaceutical perspective, better diagnostic tools will mean an opportunity for effective treatment development. This is where imaging can play a huge role. In 5-10 years’ time, as new AD treatments become available, having a diagnostic test that identifies the brain pathology the treatment targets can help ensure that the right patient gets the right treatment.”

 

Refs

* – World Health Organization. Dementia: a public health priority. Geneva : World Health Organization, 2012. ISBN 978-92-4-156445-8.
** – Hyman BT. The Neuropathological Diagnosis of Alzheimer’s Disease. Clinical-Pathological Studies. Neurobiol Aging.1997 Jul-Aug;18(4 Suppl):S27-32
*** Alzheimer’s Disease International World Alzheimer’s Report 2011 – available at http://www.alz.co.uk/research/WorldAlzheimerReport2011ExecutiveSummary.pdf