Researchers at Asan Medical Center (AMC) have found a method that uses a magnetic resonance imaging (MRI) equipment to predict delayed brain injury after carbon monoxide poisoning, the hospital said Tuesday.

Patients that come into the emergency room with CO poisonings, such as gas leaks and fires, regularly show no eye-catching symptoms once they receive emergency treatment. After discharge, however, they may show signs related to brain damage in the next few weeks. Such symptoms may lead to severe illnesses and sometimes even death, it said.

Delayed brain injury occurs in about 20 to 40 percent of patients recovering from CO poisoning and shows neurological symptoms such as decreased consciousness, cognitive impairment, Parkinson’s and gait disturbance within a few weeks after receiving initial treatment.

The research team, led by Professor Jeon Sang-beom of the neurology department and Professors Sohn Chang-hwan and Kim Won-young of the emergency medicine department at the hospital, have found that by analyzing the results of a brain MRI they could predict delayed brain injuries caused by CO poisoning.

The researchers analyzed brain MRIs from 387 patients, discharged from April 2011 to December 2015 without neurological abnormalities after acute CO poisoning.

Despite the absence of neurologic symptoms, 104 patients had an acute abnormal pattern on their MRI. Among them, 76 patients had delayed brain damage after discharge. In the remaining 283 patients, who had no acute abnormality patterns on their MRI, only 25 patients newly developed symptoms of delayed brain injury after release.

As a result, the team concluded that even if an acute CO poisoning patients shows no specific neurological symptoms after receiving emergency treatment, there is a 73-percent possibility that a severe anomaly pattern on an MRI scan can lead to delayed brain damage.

Also, the researchers classified brain MRI results of patients with delayed brain damage into three patterns -- putamen lesion, diffuse lesion, and local lesion. The team further divided local lesion into three more categories – focal-form lesion, patch-form lesion, and regional-form lesion.

By analyzing the three categories, the team was able to predict delayed brain damage with a sensitivity of 75 percent and specificity of 90 percent. The researchers expect that by predicting delayed brain damage in advance, they can minimize aftereffects and reduce mortality by providing early treatment.

“There is clinical significance in observing acute brain lesions due to carbon monoxide poisoning and predicting future neurological symptoms with its results,” Professor Jeon said. “The treatment of CO poisoning requires not only an initial treatment but also a thorough examination to find any delayed brain damages.”

However, the team also noted, although the most effective treatment to treat acute CO poisoning and prevent delayed brain damage is high-pressure oxygen therapy, which uses specialized medical equipment called a chamber, there are only two or three hospitals that have the device in the metropolitan area. Such lack of machinery makes it difficult for patients with carbon monoxide poisoning to receive proper treatment, it added.

“Based on the results of this study, more research into developing a new guideline treatment by linking brain MRI with blood biomarkers and hyperbaric oxygen therapy needs to happen,” Professor Sohn said.

The results of the research were published in the JAMA Neurology, an international journal in the field of neurology.