Repetitive brain traumas such as concussions, which often affect football players, could be detected earlier using a brain imaging technique, researchers say.

In spite of the risks faced by professional athletes, the only way to currently confirm a diagnosis of chronic traumatic encephalopathy, or CTE, is by autopsy.

One indicator of CTE is an accumulation in "clumps" of tau, a kind of protein, in regions of the brain involved in mood and thinking — which can be seen in PET scans.

"The distribution pattern of the abnormal brain proteins, primarily tau, observed in these PET scans, presents a 'fingerprint' characteristic of CTE," said senior study author Dr. Jorge Barrio, a professor of molecular and medical pharmacology at UCLA's David Geffen School of Medicine.

Such scans have been used to detect abnormal tau clumps in the brains of 14 retired professional football players, researchers at UCLA reported in the Proceedings of the National Academy of Sciences.

The scans of the athletes' brains – made possible by combining a chemical marker with the PET scan – were compared with those of 19 men and nine women who had healthy brains, and 12 men and 12 women of similar ages with Alzheimer's disease. CTE is often misdiagnosed as Alzheimer's.

While there is currently no treatment for CTE, early detection would allow doctors to monitor the progress of the disease, and could help athletes make decisions on whether to continue a playing career.

Symptoms of CTE can include loss of short-term memory and certain cognitive abilities. They can also manifest as mood changes, including aggressiveness, irritability, depression and suicidal behavior.

An athlete could go decades without experiencing the initial symptoms following a series of concussions, the researchers noted — making early detection all the more important.

A recent study published in the journal Neurosurgery determined that of 14 professional athletes and three high school football players who died suddenly and unexpectedly, 10 pros and one student displayed evidence of CTE during autopsy.

The UCLA study is one of several avenues of research conducted by scientists in the U.S. with the hopes of diagnosing CTE early.

"This work offers compelling evidence of the ability of [our brain imaging technique] to detect neuropathology in the living brain of American football players in a manner consistent with the pattern of deposition found at autopsy," the UCLA researchers wrote.