Alzheimer’s diagnosis might become simpler with new brain imaging method

By Dr. Ananya Mandal, MDSep 20 2018

Accurate diagnosis of Alzheimer’s disease may be difficult in most patients as similar symptoms can be seen in several other disease conditions as well. Researchers have developed a new brain imaging method that can show the exact presence and distribution of the tau protein depositions in the brain of a persons with Alzheimer’s disease. These tau protein deposits are characteristic of Alzheimer’s disease.

Oskar Hansson. Hansson, professor of clinical memory research at Lund University in Sweden and study leader said in a statement, “The method works very well. I believe it will be applied clinically all over the world in only a few years.” The study results were published in the latest issue of the JAMA (Journal of the American Medical Association).

Alzheimer’s diagnosis might become simpler with new brain imaging method​. Image Credit: Lightspring / Shutterstock

There are two forms of proteins deposits in the brain in patients with Alzheimer’s disease – the tau protein that forms tangles in the brain and the beta amyloid protein that causes plaque formation within the brain. The beta amyloid protein spreads across the brain first and the tau protein spreads at a later stage from the temporal lobes of the brain to other parts. Senior researcher Rik Ossenkoppele, Lund University and Amsterdam University Medical Center explained that the first symptoms and problems begin to appear in the patient when the tau starts to spread and the neurons or brain cells begin to die. Memory difficulties are detected and at that time there is increased tau in the brain Ossenkoppele said and this clinches the diagnosis of Alzheimer’s.

The team including those from Lund-Malmö in southern Sweden as well as others from San Francisco and Seoul studied over 700 patients and looked at memory tests of these patients. They performed PET scans on the brains of these patients and detected tau presence in the brain. PET scans use radioactive markers that light up the desired areas. Oskar Hansson explained that they used specific “tau markers” that were administered intravenously. On scanning the Alzheimer tau presence or absence was clearly detected.

The researchers explain that this new tau-PET method was capable of detecting 90-95 per cent of all cases of Alzheimer’s disease and gave only a few false positive results. This proved its superiority over other methods such as MRI. Beta-amyloid PET is also being used these days for diagnosis and tau-PET method showed fewer false positive results than even the beta-amyloid PET method state the authors of the study.

Hansson said, “If you are found to have tau in the brain according to tau-PET, it is, with few exceptions, due to Alzheimer's disease. If you have normal tau-PET and mild to moderate dementia, your memory problems are most likely due to other neurological diseases.” Early diagnosis can help initiate medication therapy earlier say the experts. This method would also be useful in clinical trials testing drugs to be used in Alzheimer’s to check for their effectiveness.