New MRI Method for Diagnosing Dementia

Alzheimers disease may be diagnosed using MRI in a new way

(RxWiki News) A test called a spinal tap can test for markers of Alzheimer’s disease (AD). The markers can help doctors tell if dementia is AD or not. An MRI may offer a less invasive way to look at markers.

Researchers used magnetic resonance imaging (MRI) to estimate the amount of two proteins that build up in the brain in Alzheimer’s disease (AD). They compared the estimates to the levels found in spinal fluid tests. The MRI method gave the same diagnosis as the spinal tap about 75 percent of the time.

The MRI method may allow doctors to diagnose AD without the use of spinal tap, which can be invasive and unpleasant.

"Ask a doctor which AD tests are right for you."

The study, led by Corey T. McMillan, PhD, of the Department of Neurology at the University of Pennsylvania, enrolled 185 patients with AD or frontotemporal lobar degeneration (FTLD).

FTLD is a degenerative dementia affecting about as many people as AD. It is different from AD because it is linked to changes in the parts of the brain that control personality and behavior.

AD is linked to the build up of tau and beta amyloid in the brain and affects parts of the brain that control learning and memory. AD and FTLD can share symptoms, so it can be hard to tell them apart in some cases.

The researchers wanted to know if they could use an MRI to look for markers of AD – tau and beta amyloid – that would help doctors know which type of dementia a person had.

All the people in the study had a spinal tap to test for levels of tau and beta amyloid in their spinal fluid. The participants also had an MRI of the brain.

Using the MRI, the researchers looked at the brain tissue and devised a way to estimate the amount of tau and beta amyloid in the brain. 

Then they compared the MRI estimates to the spinal fluid levels to see how their method compared. The MRI estimates gave the same diagnosis as spinal fluid tests about 75 percent of time.

The authors concluded that this method is not invasive like a spinal tap, so may be a better first method of screening. They also said the method could be helpful for new treatment trials.

A spinal tap requires a large needle to be inserted into the spine, which can be painful and scary for some patients. However, MRIs can be costly – up to $5,000. 

Distinguishing between the two types of dementia may help caregivers plan for the progression of the disease. And it may help doctors prescribe the most appropriate treatments.

There are no treatments to stop or slow the progression of AD or FTLD. All treatments currently in use manage symptoms but do not affect the disease process.

Publishing alongside this study report, Christian Habeck, PhD, of Columbia University, and Jennifer L. Whitwell, PhD, of the Mayo clinic, commented about this new method of using MRI.

They commended the new method of using MRI testing by saying that it may be helpful in clinical practice and in future research for dementia.

However, they also said that the method needs to be used again in a separate set of patients. The patients in the study were used to create the method, so the accuracy of the method needs to be shown in a different set of people.

More research needs to be done before this method will be available for clinical use.

The study was published December 26 in Neurology.  The study authors were funded by the Wyncote Foundation, Alfonso Martín Escudero Foundation and the National Institutes of Health. The authors report no conflicts of interest for this study.

Review Date: 
January 10, 2013