Diffusion-weighted imaging may detect brain lesions after carbon monoxide poisoning

Can diffusion-weighted imaging (DWI) detect acute brain lesions? Can it also assess the probability that carbon monoxide poisoning has initiated delayed neurological sequelae (DNS)? According to a study conducted by researchers from the Asan Medical Center at the University of Ulsan College of Medicine in Seoul, South Korea, the answer is yes.  

Treating acute carbon monoxide (CO) poisoning requires preventing such neurological consequences, according to a study recently published in JAMA Neurology. MRI technology plays an important role in assessing DNS, which can manifest two to six weeks after initial resuscitation.  

"Documenting acute lesions that can potentially indicate the subsequent development of DNS could give clinicians and researchers useful information for understanding the pathophysiology of DNS and targeting prevention," said lead author of the study Sang-Beom Jeon, MD, PhD. "We aimed to investigate the prevalence and radiological characteristics of acute brain lesions (ABLs) on diffusion weighted imaging (DWI), which we termed ABLDs, and to determine whether the presence of ABLDs is related to the development of DNS in patients after acute CO poisoning."  

Over the course of roughly four years, from April 2011 to December 2015, researchers conducted the registry-based observational study at the Asan Medical Center in Seoul. In total, 387 patients who had acute carbon monoxide poisoning qualified for the study and underwent DWI. Demographic data, risk factors, level of consciousness at arrival, vital signs and lab results from all patients were collected accordingly.  

"Every patient received 100 percent oxygen by facial mask or mechanical ventilator following endotracheal intubation. Hyperbaric oxygen therapy was delivered if patients manifested signs of serious poisoning (unconsciousness, neurological signs, cardiovascular dysfunction, or severe acidosis) or had a carboxyhemoglobin level of 25 percent or higher," Jeon et al. wrote.   

Furthermore, researchers assessed DNS through the following methods:  

• Routinely requesting neurology consultations for the assessment of neurological signs before discharge.
• Informing patients of DNS symptoms and the researchers contact information.
• Visiting patients to regular follow-up visits in the neurology clinic after discharge.
• Performing telephone interviews with the patient using a questionnaire.
• And having neurologists evaluate DNS but did not have dedicated tools to specify DNS.

Researchers found that of the 387 patients tested, 104 showed brain lesions on diffusion-weighted imaging and delayed neurological sequala occurred in 101 patients, according to the study. The most common locations of ABLs were in the globus pallidus, though all varied in size, shape and distribution. Additionally, 37 percent were women, with a median age of 42 years, and the median time from the end of CO exposure to visiting the hospital was almost three hours.  

"We showed that the presence of ABLDs during the acute phase of CO poisoning was significantly associated with a 14-fold higher risk of developing DNS in the future compared with those who did not have acute brain lesions (ABLs)," Jeon concluded. "The sensitivity and positive predictive value of ABLDs to assess the probability of DNS was approximately 75 percent, and the specificity and negative predictive value were approximately 90 percent. Therefore, we concluded that DWI is a useful modality for detecting ABLs and assessing the probability of DNS in patients with CO poisoning."