PET Imaging May Help Find Alzheimer’s

PET imaging, otherwise known as positron emission tomography, is starting to be used to look for signs of Alzheimer’s disease within a patient’s brain tissue.  Rather than used dated pathological techniques to guess when a patient might suffer the onset of Alzheimer’s, PET imaging can be used to look for traces of damaged brain tissue that is synonymous with Alzheimer’s disease.

ScienceDaily  — The use of positron emission tomography (PET) imaging may help identify findings in brain tissue associated with Alzheimer’s disease (AD), according to two articles published Online First by Archives of Neurology, one of the JAMA/Archives journals.

As scientists seek to understand more about AD and other forms of dementia, they are exploring the use of PET, according to background information in the article. This imaging technique involves the use of radioactive tracers to highlight areas of the brain affected by these conditions. Various teams of researchers are studying the effectiveness of different types of tracers for identifying brain findings associated with these conditions.

In one study, David A. Wolk, M.D., from the Penn Memory Center in Philadelphia, and colleagues, evaluated use of a tracer called fluorine 18-labeled flutemetamol for imaging the brain. The study involved conducting PET scans on seven patients who were given a dose of this substance. All had previously undergone a biopsy for normal pressure hydrocephalus, a progressive condition that includes dementia and can be difficult to distinguish from AD. Researchers found correspondence between readings of the PET scans and evidence of amyloid lesions — the plaque associated with AD — provided by microscopic evaluation of the biopsied tissue.

In another study, Adam S. Fleisher, M.D., from Banner Alzheimer’s Institute in Phoenix, and colleagues, evaluated PET imaging using the tracer florbetapir F 18. The study population included 68 individuals with probable AD, 60 individuals with mild cognitive impairment, and 82 healthy individuals who served as controls. PET scanning was used to monitor activity of the agent being studied. These researchers found differences in the brain uptake of florbetapir F 18, between the three groups, and in the detection of amyloid plaque; the differences may be large enough to help distinguish between the conditions, and between impaired versus unimpaired brains.

The authors of both articles suggest that their results may demonstrate ways in which PET imaging can be used with selected tracers to help identify findings associated with AD. “With the potential emergence of disease-specific interventions for AD,” state Wolk et al, “biomarkers that provide molecular specificity will likely become of greater importance in the differential diagnosis of cognitive impairment in older adults.” Indeed, Fleisher et al write, “Amyloid imaging offers great promise to facilitate the evaluation of patients in a clinical setting.”

Commentary: Amyloid Imaging-Liberal or Conservative? Let the Data Decide

In an editorial accompanying the papers, William J. Jagust, M.D., from the Helen Wills Neuroscience Institute at the University of California, Berkeley, comments on the role of amyloid in AD and the detection of this plaque as “a topic of active investigation.” The articles by Wolk et al and Fleisher et al, he suggests, “continue to advance the field.”

Jagust notes that the study by Fleisher et al attempted to define cutoffs for positive or negative presence of amyloid. “Most clinical imaging methods rely on interpretation, not quantitation,” he states. “Nevertheless, quantitation of these scans has considerable value because it provides a reliable measure that can be compared across laboratories on either a continuous or dichotomous level.”

Jagust also discusses the problem of how to treat “borderline” or “intermediate” results. He notes that the study by Wolk et al found “perfect agreement” between the scans and the biopsied tissue in terms of positive or negative ratings.

Further, Jagust adds, the two studies show that cutoff levels may be distinct from agent to agent. “These are likely to be related to differences in the tracer as well as to differences in the methods already noted,” he says. Nevertheless, points out Jagust, “Another interesting point is how exceptionally well all of these tracers perform in comparison to pathology.”

For more http://www.sciencedaily.com/releases/2011/07/110712192045.htm

Share

Posted: July 25th, 2011 under Uncategorized.

RSS Medical Imaging News

  • Novel ultrasound technology to screen for heart conditions developed by engineers October 29, 2014
    Engineers have determined, for the first time, the impact of a ring-shaped vortex on transporting blood flow in normal and abnormal ventricles within the human heart, and have developed a novel ultrasound technology that makes screening cheaper and much easier, making it possible to reach a large number of people and even infants.
  • Brain abnormalities found in chronic fatigue patients October 29, 2014
    An imaging study has found distinct differences between the brains of patients with chronic fatigue syndrome and those of healthy people.
  • New technology shows promise for delivery of therapeutics to the brain October 28, 2014
    Researchers have created “a tool for blood-barrier-brain disruption that uses bursts of sub-microsecond bipolar pulses to enhance the transfer of large molecules to the brain.” According to the authors, the current medical use of chemotherapy to treat brain cancer can be inefficient because of the blood-brain-barrier that impedes the delivery of drugs out of […]
  • Tomosynthesis improves cancer detection in women with dense breast tissue October 28, 2014
    As of October 2014, 19 states have enacted laws requiring women to be directly informed if they have dense breasts and would benefit from supplemental screening. However, the recommended type of supplemental screening for women with dense breasts remains unclear. With 15 additional states considering similar laws and federal legislation introduced, physician […]
  • Preventative action prior to brain surgery: Ultra-high-field MRI reveals language centers in brain in much more detail October 28, 2014
    It is now possible, for the first time, to demonstrate that the areas of the brain that are important for understanding language can be pinpointed much more accurately using ultra-high-field MRI (7 Tesla) than with conventional clinical MRI scanners. This research helps to protect these areas more effectively during brain surgery and avoid accidentally damag […]
  • Ultrasound guides tongue to pronounce 'R' sounds October 27, 2014
    Using ultrasound technology to visualize the tongue’s shape and movement can help children with difficulty pronouncing “r” sounds, according to a small study. The ultrasound intervention was effective when individuals were allowed to make different shapes with their tongue in order to produce the "r" sound, rather than being instructed to make a sp […]
  • Brain development in utero observed by researchers October 27, 2014
    New investigation methods using functional magnetic resonance tomography (fMRT) offer insights into fetal brain development. These "in vivo" observations will uncover different stages of the brain's development. A research group has observed that parts of the brain that are later responsible for sight are already active at this stage.
  • New hope for potential prostate cancer patients October 25, 2014
    It has been more than 30 years since the last major advancement in prostate cancer screening technology, and the latest advancement is now available in the United States. It is estimated that 2014 will see more than 240,000 new cases of prostate cancer, and more than 29,000 deaths from the disease.
  • Breast cancer tumor response to neoadjuvant chemotherapy measured October 23, 2014
    It may be possible to use Diffuse Optical Spectroscopic Tomographic imaging (DOST) to predict which patients will best respond to chemotherapy used to shrink breast cancer tumors before surgery, a study shows.
  • New window of opportunity to prevent cardiovascular, diseases October 23, 2014
    Future prevention and treatment strategies for vascular diseases may lie in the evaluation of early brain imaging tests long before heart attacks or strokes occur, according to a systematic review conducted by a team of cardiologists, neuroscientists, and psychiatrists.

News Items

Links