QSM scan shows brainstem damage is key to long-term physical and psychological effects of severe COVID-19 infection

In critically ill patients with COVID-19, an ultra-high field quantitative susceptibility mapping (QSM) scanner, called the 7T scanner, allows brainstem to be sensitive to the long-term effects of COVID-19. It has become clear that this is a vulnerable area. Obvious changes can be seen several months after admission.¹

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Symptoms of acute post-COVID-19 syndrome, known as “long coronavirus,” may be related to brainstem abnormalities that have been reported in patients infected with COVID-19. However, conventional MRI scans have not yet shown consistent brainstem abnormalities on follow-up. Using more serious MRI techniques, such as QSM, researchers may be able to identify more subtle changes in the brainstem and other areas of the brain.¹

Previous post-mortem studies of patients who died from severe COVID-19 infection in the early stages of the pandemic showed changes in the brainstem, but these were not due to direct infiltration of the virus into the body, but rather after infection. It was thought to be caused by an immune response. brain. This clarity is important given the brainstem's critical role in many basic bodily functions.²

“The brainstem is a critical connecting box between our consciousness and what's happening inside our bodies,” James Rowe, who co-led the study, said in a news release. “The ability to see and understand how the brainstem changes in response to COVID-19 will help us more effectively explain and treat long-term effects.”²

In this study, researchers investigated QSM abnormalities in the brainstem of COVID-19 patients after hospitalization, according to subregions defined as regions of interest. Once the scans were completed, tests were performed to determine whether brainstem susceptibility correlated with clinical measures of disease severity and laboratory measures of inflammation.¹

A total of 31 people participated in the study. For patient data, the researchers extracted the mean χ from significant clusters indicative of atrophy and fit nine linear models to test associations with laboratory and clinical outcomes. Notably, this study was conducted in patients hospitalized with severe COVID-19 infection early in the pandemic, before a vaccine was available.^1,2

Regional mean χ was increased in the brainstem of the COVID group compared to healthy controls (HC) and was mainly localized in the pontine subregion of the brainstem and medulla oblongata. Voxel-wise analysis of the brainstem identified two major clusters located in the medullary region, with significantly increased χ in the COVID group. Importantly, these clusters partially overlap with brainstem reasons known to be related to body homeostasis and respiratory function.¹

The highest C-reactive protein (CRP) detected during hospitalization was positively correlated with the mean χ value extracted from clusters identified in the medullary portion of the brainstem. Furthermore, associations with World Health Organization severity index and length of hospital stay were weak. Regarding clinical evaluation, no other significant trends were observed.¹

“The fact that we see abnormalities in parts of the brain associated with breathing strongly suggests that the long-term symptoms are an effect of inflammation in the brainstem after infection with COVID-19,” said Katarina, lead author of the study.・Mr. Rua stated in his paper. News release.²

Based on these results, the researchers suggest that brainstem damage occurs following hospitalized COVID-19 infection, impairing autonomic nervous function, and that this contributes to the clinical symptoms of patients with long-term COVID-19 infection. We hypothesize that this will lead to sustainability. Interestingly, the researchers noted that a similar pattern may be observed after severe traumatic brain injury.¹

Brainstem damage caused by COVID-19 not only causes long-term physical effects. The 7T scanner showed some of the psychiatric effects of the disease, as the brainstem monitors fatigue and anxiety, as well as shortness of breath. Dr. Lowe talked about how patients with the most pronounced immune responses showed correspondingly higher levels of anxiety and depression.^1,2

“This approach is a valuable tool to probe the long-term effects of COVID-19 and other potential SARS-CoV diseases on the brain to inform acute and long-term treatment strategies to aid recovery. “This could be the case,” the researchers concluded. .¹

References

1. Rua C, Raman B, Rodgers CT, et al. Quantitative susceptibility mapping of COVID-19 at 7T: Association of brainstem effects and outcomes. brain. 2024:awae215. doi:10.1093/brain/awae215

2. University of Cambridge. Ultra-high-power MRI scans have shown that damage to the brain's “control centers” is behind the symptoms of long-term coronavirus infections. Yurec Alert! News Release. Released on October 7, 2024. Accessed October 9, 2024. https://www.eurekalert.org/news-releases/1060117