Nov. 16, 2011 at 4:10 PM ET
Hospitals around the country may already have the technology to inexpensively diagnose – or rule out – Alzheimer’s disease, two new studies suggest.
The studies looked at an MRI method that can cheaply and accurately detect changes in the brain that are associated with Alzheimer’s disease. Currently doctors who need an accurate diagnosis must send patients off to a center with a PET scanner. Along with a higher price tag, images from PET scanners require the use of radioactive tracers which carry some risks if a patient is tested repeatedly.
One of the new studies was published in Alzheimer’s and Dementia, the other in Neurology.
"This can become a useful way of diagnosing the disease and managing therapy," said study co-author Dr. John Detre, a professor of neurology and radiology at the Perelman School of Medicine at the University of Pennsylvania. "It can also be used an inexpensive and non-invasive way to document a patient’s response to new drugs. You can repeat tests without risk since you don’t have to inject a radioactive substance every time you want a new measurement."
PET scanners look at how the various brain regions use glucose – the fuel that keeps us thinking. Doctors can tell by the pattern of glucose use whether a brain is developing Alzheimer’s because nerve cells use less glucose when they are beginning to fail. The pattern of bright and dull spots on a scan tell doctors whether brain regions typically hit by Alzheimer’s have been damaged.
The new MRI technique looks at blood flow in each brain region. Detre and his colleagues showed that patterns of blood flow in Alzheimer’s patients mirrored those of glucose use, which means that MRI scans can give the same information as more expensive PET scanners.
The new technique may also help drive drug discovery. Pharmaceutical companies developing Alzheimer’s treatments could inexpensively track patients and, because there is little exposure to radiation, follow-ups can be more frequent with less risk to trial participants, Detre said.
The new method requires only a standard MRI machine and computer programs that are already available to medical centers, Detre said. So, if the technique catches on, it could be widely available in a very short time.
There is no cure for Alzheimer’s, no matter how early the disease is diagnosed. But patients can use an early diagnosis to get their lives in order while they are still cognitively intact and also as a chance to sign up for clinical trials.