Advances in Brain Imaging Create Bright Future For People With Degenerative Diseases Like Parkinson's

Yale School of Medicine
Monday, 24 July 2000

Ongoing advances in brain imaging will pave the way for more effective treatment of neurodegenerative diseases like Parkinson's and Alzheimer's, Yale researchers report in the current issue of Science.

"We're an aging population and neurodegenerative diseases are being diagnosed in a growing number of people," said John Seibyl, associate professor of diagnostic radiology and psychiatry at Yale School of Medicine. "We now have tools, many of which have been developed here at Yale, which provide valid biological objective markers of changes occurring in the brains of patients with these diseases, particularly Parkinson's disease."

The tools include diverse imaging methods such as magnetic resonance imaging (MRI), which provides views of anatomic and structural brain abnormalities. Other methods include imaging techniques that measure brain chemicals, such as single photon emission tomography (SPECT) and positron emission tomography (PET). These, Seibyl said, are even better than MRI for assessing patients with neurodegenerative diseases.

The next great horizon in Parkinson's disease and Alzheimer's dementia treatments are designed to slow or arrest the progressive loss of brain cells that characterize the disease, Seibyl said.

"These neuroprotective drugs are promising, but the only way to objectively evaluate which ones are going to be effective, is by using powerful imaging tools," Seibyl said. "These imaging biomarkers are an objective and quantifiable means for assessing how fast brain cells are being lost and when neuroprotective drugs are having a beneficial effect."

A biomarker is a radioactively tagged medication that binds to specific brain cells involved in neurodegenerative diseases. As cells die, they lose the ability to bind to the radioactive tag. The scans demonstrate the extent of the loss by following the patients over time.

Brain imaging in live patients provides a powerful and easily accessible view of the molecular pathology of neurodegenerative diseases. It is essential for determining the chronic timecourse of these disorders, from pre-clinical through diagnosis to end-stage disease, and for assessing the potential of medications that might impede the disease process.

The past decade has seen rapid development of SPECT and PET detection devices or cameras. Improvements have been made in both of these technologies. Imaging can now be used to determine whether a patient has the disease, whether the disease has spread, and, if so, how severely.

Neurotransmitter receptor imaging is the best available biomarker for neurodegenerative diseases and has been used to monitor disease onset, severity and progression, and the pre-clinical phase of the degenerative process in Parkinson's, Alzheimer's and Huntington's Disease.

Kenneth Marek, M.D., associate professor of neurology at Yale co-wrote the article. Seibyl is also chief of the Section of Nuclear Medicine and runs the Neurospect Center, a research lab devoted to brain imaging at Yale.

For more information, or to contact Yale School of Medicine, see their website at: info.med.yale.edu/ysm/