Ultra-high-power MRI scan reveals damage to the brain's 'control center' behind long-term symptoms of coronavirus infection

Researchers from the Universities of Cambridge and Oxford have now used ultra-high resolution scanners that allow them to see detailed images of living brains to monitor the potential negative effects of coronavirus infection on the brain.

The researchers scanned the brains of 30 people who were hospitalized with severe coronavirus infections early in the pandemic, before a vaccine was available. Researchers have found that COVID-19 damages areas of the brainstem associated with shortness of breath, fatigue, and anxiety.

The powerful MRI scanner used in this study is known as a 7 Tesla or 7T scanner and can measure inflammation in the brain. The results were published in a magazine brainwill help scientists and clinicians understand the long-term effects of COVID-19 on the brain and other parts of the body. Although this study was started before the long-term effects of coronavirus were recognized, it will help us better understand the situation.

The brainstem, which connects the brain to the spinal cord, is the control center for many basic life functions and reflexes. A collection of nerve cells in the brain stem, known as the nucleus, is responsible for regulating and processing essential bodily functions such as breathing, heart rate, pain, and blood pressure.

“What happens in and around the brainstem is critical to quality of life, but scanning for inflammation in brainstem nuclei in living humans has been impossible due to their small size and difficulty in location.” Lead author Dr Katharina Rua from the Department of Clinical Neuroscience said: “Normally, scientists only take a close look at the brainstem during post-mortem examinations.”

“The brainstem is a critical junction box between our consciousness and what's happening inside our bodies,” said study co-lead Professor James Lowe, also from the Department of Clinical Neuroscience. “The ability to see and understand how the brainstem changes in response to COVID-19 will help us more effectively explain and treat its long-term effects.”

Early in the COVID-19 pandemic, before an effective vaccine was available, postmortem studies of patients who died from severe COVID-19 infection showed changes in the brainstem, including inflammation. Many of these changes were thought to be due to the immune response following infection rather than direct virus entry into the brain.

“People who became severely ill early in the pandemic showed long-term brain changes, likely caused by an immune response to the virus. But it is difficult to measure that immune response in living humans. It’s difficult,” Lowe said. “Regular hospital-grade MRI scanners cannot see inside the brain in the chemical and physical details that we need.”

“But with the 7T scanner, we can now measure these details. Because activated immune cells interfere with ultra-strong magnetic fields, we can now detect how immune cells are behaving. “It will be,” Rua said. “Cambridge was special because we were able to scan even the most serious and infectious patients early in the pandemic.”

Many patients hospitalized early in the pandemic reported fatigue, shortness of breath, and chest pain as long-term and bothersome symptoms. The researchers hypothesized that some of these symptoms are the result of damage to key brainstem nuclei, and that damage persists long after the coronavirus infection has passed.

The researchers identified multiple regions of the brainstem, particularly the medulla oblongata, pons, and midbrain, showing abnormalities consistent with a neuroinflammatory response. The abnormality appeared weeks after admission to the area of ​​the brain responsible for controlling breathing.

“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,” Lua said. “These effects go far beyond the effects of age and gender and are even more pronounced in people with severe COVID-19 infection.”

In addition to the physical effects of Covid-19, the 7T scanner provided evidence of some of the psychological effects of the disease. The brainstem monitors shortness of breath, fatigue, and anxiety. “Mental health is closely linked to brain health, and patients with the most pronounced immune responses also showed higher levels of depression and anxiety,” Dr. Lowe said. “Because of the close relationship between physical health and mental health, changes to the brain stem due to COVID-19 may also lead to poor mental health.”

Researchers say the results could help understand other conditions associated with brainstem inflammation, such as MS and dementia. The 7T scanner can also be used to monitor the effectiveness of various treatments for brain diseases.

“This was a great collaboration in the midst of a pandemic, when testing was extremely difficult. We were surprised at how well the 7T scanner worked,” Lua said. “I was really impressed by how effectively the collaboration between so many different researchers came together in the heat of the moment.”

This research was supported in part by the NIHR Cambridge Biomedical Research Centre, the NIHR Oxford Biomedical Research Center and the University of Oxford Coronavirus Medicine Department Rapid Response Fund.