Using Tau PET Scan to Distinguish Alzheimer Disease from Other Neurodegenerative Disorders

MedicalResearch.com Interview with:
PET scanner Wikipedia imageRik Ossenkoppele
PhD
Lund University & VU University Medical Center
Oskar Hansson – Lund University

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: [18F]flortaucipir is a relatively novel PET tracer that can be used to detect tau pathology in the living human brain. Previous studies have shown a robust signal in patients with Alzheimer’s disease, but in patients with other types of dementia the signal was more variable.

We aimed to assess the ability of [18F]flortaucipir PET to distinguish Alzheimer’s disease from other neurodegenerative disease in more than 700 study participants. T

he main finding was that [18F]flortaucipir discriminated Alzheimer’s disease patients from patients with other neurodegenerative diseases with high accuracy. Furthermore, [18F]flortaucipir PET outperformed established MRI markers and showed higher specificity than amyloid-β PET.  Continue reading

Amyloid PET Scan Useful in Memory Evaluation

MedicalResearch.com Interview with:
Arno de Wilde, MD / PhD candidate

Department of Neurology & Alzheimer Center
Amsterdam Neuroscience
VU University Medical Center
Amsterdam, the Netherlands

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Previous studies assessing the clinical utility of amyloid imaging used very selected research populations, limiting the translatability to clinical practice. In contrast, we used an unselected memory clinic cohort, offering amyloid PET to ALL patients visiting our memory clinic, and for the purpose of this study, we implemented amyloid PET in our routine diagnostic work-up. Our results demonstrate that amyloid PET has important consequences, in terms of diagnosis and treatment changes, for a significant number of patients within a situation that closely resembles clinical practice. I think that these results are an important step in ‘bridging the gap’ between using amyloid PET in a research setting versus daily clinical practice.

Continue reading

How a PET Can Save Your Heart

MedicalResearch.com Interview with:

Dr-W-Robert-Taylor

Dr. Taylor

Robert Taylor, MD, PhD
Marcus Chair in Vascular Medicine
Executive Vice Chair, Medicine
Director, Division of Cardiology
Professor of Medicine and
Biomedical Engineering
Emory University School of Medicine

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: The early identification and localization of bacterial infections is a critical step for initiating effective treatment.   This is particularly challenging in the setting of infections associated with implanted medical devices.  We have developed a highly specific probe for bacteria that is based on the fact that bacteria have a specific system for taking up maltodextrins which are polysaccharides that mammalian cells cannot take up directly.  We can label this probe with either a fluorescent of radioactive tag that allows visualization of the bacteria.

In the current article, we have used an animal model of implantable cardiac devices to demonstrate that our probe is very specific and sensitive for detecting bacterial infections.  It is worth noting that these are subclinical infections that could not be detected by any other means except for surgical removal.

Continue reading

Patients and Providers Feel Amyloid PET Scanning Diagnosis of Alzheimer’s Disease Beneficial

MedicalResearch.com Interview with:

Liana Apostolova, MD, MSc, FAAN Barbara and Peer Baekgaard Professor  in Alzheimer's Disease Research Professor in Neurology, Radiology. Medical and Molecular Genetics Indiana University School of Medicine Indiana Alzheimer's Disease Center Indianapolis, IN 46202

Dr. Apostolova

Liana Apostolova, MD, MSc, FAAN
Barbara and Peer Baekgaard Professor  in Alzheimer’s Disease Research
Professor in Neurology, Radiology. Medical and Molecular Genetics
Indiana University School of Medicine
Indiana Alzheimer’s Disease Center
Indianapolis, IN 46202

MedicalResearch.com: What is the background for this study?

Response: While many studies have evaluated the diagnostic or prognostic implications associated with amyloid PET, few have explored its effects on the patient or caregiver. Amyloid imaging does not only help clinicians with their diagnosis and management. It also affects patient and caregiver decisions related to lifestyle, financial and long-term care planning, and at times also employment. Few studies to date have explored patient and caregiver views on the clinical use of amyloid PET and the potential benefits they could derive from having more precise diagnosis.

Continue reading

PET Scan Identifies Low Serotonin Functioning Linked To Suicidal Behavior

Maria A. Oquendo, M.D. Professor of Psychiatry Vice Chair for Education Columbia University Medical Center American Psychiatric Association, President International Academy of Suicide Research, President

Dr. Maria Oquendo

MedicalResearch.com Interview with:
Maria A. Oquendo, M.D.
Professor of Psychiatry
Vice Chair for Education
Columbia University Medical Center
American Psychiatric Association, President
International Academy of Suicide Research, President

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: Our team has worked for years on identifying the biological underpinnings of both risk for suicidal behavior (SB) and for predicting the lethality or medical consequences of suicidal behavior. We have shown that if you compare those who are depressed and have had SB to those who are depressed but do not have suicidal behavior, you can see clear differences in the serotonin system using Positron Emission Tomography and a molecule tagged with radioactivity. We predicted that if you could see these differences cross-sectionally, then their presence might also predict suicidal behavior and its lethality in the future. Our study showed that those with higher serotonin 1a binding in the raphe nuclei, which likely indicates low serotonin functioning, made more medically damaging suicide attempts in the two years that followed. They also suffered from more pronounced suicidal ideation in the subsequent year.

Continue reading

Research Supports Upcoming Alzheimer’s Disease Guidelines

Reston, Va.–Two new studies published in the August issue of The Journal of Nuclear Medicine (JNM) provide insight intothe potential of positron emission tomography (PET) to differentiate between types of dementia and to identify pharmaceuticals to slow the progress of dementia. With proposed National Institute on Aging (NIA) and the Alzheimer’s Association guidelines for detecting Alzheimer’s-related brain changesexpected in September, these articles give a preview of what may be to come.

Earlier this year, the NIA and the Alzheimer’s Association released new criteria and guidelines for the diagnosis of Alzheimer’s disease. The new proposed guidelines available this fall will offer additional information regarding the development of tests to measure biological changes in the brain, blood, or spinal fluid to diagnose Alzheimer’s at an earlier stage.

Earlier diagnosis of Alzheimer’s disease is the focus of the JNM article “Amyloid Imaging with 18F-Florbetaben in Alzheimer Disease and Other Dementias.” In this study researchers compared cortical amyloid deposition using 18F-florbetaben and PET in 109 controls and subjects with mild cognitive impairment (MCI), frontotemporal lobar degeneration, dementia with Lewy bodies, vascular dementia, Parkinson’s disease and Alzheimer’s disease.

The results show that 18F-florbetaben performs with the same high accuracy as previously reported with 11C-Pittsburgh Compound B—the most specific and widely used amyloid imaging agent—for distinguishing between certain types of neurodegenerative dementia, particularly for diagnosis of Alzheimer’s disease from frontotemporal dementia.

“The difference between 11C-Pittsburgh Compound B and 18F-florbetaben is that the 18F-florbetaben has a longer half life and is more affordable, making it appropriate for clinical use,” said Christopher Rowe, MD, FRACP, one of the authors of the study.  “This distinction profoundly affects treatment and prognosis and has genetic implications for the family.”

In addition to detecting Alzheimer’s disease earlier, molecular imaging can also be used in clinical trials to help develop pharmaceuticals to prevent or delay the onset of dementia. This is particularly of importance to patients with MCI who have yet to develop Alzheimer’s disease.

“We urgently need tools for conducting drug trials for MCI more efficiently,” noted Karl Herholz, MD, lead author of the study “Evaluation of a Calibrated 18F-FDG PET Score as a Biomarker for Progression of Alzheimer’s Disease and Mild Cognitive Impairment.” He continued, “Clinical outcome parameters show large variability and little sensitivity to progression at that stage, making these trials extremely costly and cumbersome. By using imaging biomarkers as primary outcome parameters, clinical trials can be performed with smaller sample sizes or shorter trial duration without loss of study power.”

The study evaluated a predefined quantitative measure—a PET score—that was extracted automatically from 18F-FDG PET scans using a sample of controls, patients with MCI and patients with Alzheimer’s disease. The PET scores provided a much higher test-retest reliability than standard neuropsychologic test scores (Alzheimer’s Disease Assessment Scale-Cognitive and Mini-Mental State Examination) and superior strength for measuring progression, as well as a valid measurement of cognitive impairment. As such, the PET scores can be considered a valid imaging biomarker to monitor the progression of MCI to Alzheimer’s disease.

“Prevention of dementia by drugs applied at MCI stage would greatly improve quality of life for patients and reduce costs of dementia care and treatment. Thus, development of such drugs and efficient tools for testing them are extremely important,” concluded Herholz.

Alzheimer’s disease is an irreversible, progressive brain disease that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks of daily living. Although treatment can slow the progression of the disease and help manage its symptoms, there is no cure for Alzheimer’s disease. The Alzheimer’s Association estimates that more five million people are currently living with the disorder.

Authors of the article “Amyloid Imaging with 18F-Florbetaben in Alzheimer Disease and Other Dementias” include: Victor Villemagne, Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, Victoria, Australia, Department of Medicine, University of Melbourne, Parkville, Victoria, Australia and The Mental Health Research Institute of Victoria, Parkville, Victoria, Australia; Kevin Ong and Christopher Rowe, Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, Victoria, Australia and Department of Medicine, University of Melbourne, Parkville, Victoria, Australia; Rachel S. Mulligan, Svetlana Pejoska, Gareth Jones, Graeme O’Keefe, Uwe Ackerman, Henri Tochon-Danguy and J. Gordon Chan, Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, Victoria, Australia; Colin L. Masters, The Mental Health Research Institute of Victoria, Parkville, Victoria, Australia; and Gerhard Holl, Cornelia B. Reininger, Lueder Fels, Barbara Putz and Beate Rhode, Bayer Schering Pharma, Berlin, Germany.

Authors of the article “Evaluation of a Calibrated 18F-FDG PET Score as a Biomarker for Progression in Alzheimer Disease and Mild Cognitive Impairment” include: Karl Herholz, Sarah Westwood and Cathleen Haense, Wolfson Molecular Imaging Centre, School of Cancer and Enabling Sciences, University of Manchester, Manchester, United Kingdom, and Graham Dunn, School of Community Based Medicine, University of Manchester, Manchester, United Kingdom.