Long COVID impact on brain caught in advanced MRI

Photo by Fusion Medical Animation on Unsplash

Swedish scientists have used an advanced MRI technique to find a pattern of change in the white matter in brain among the long COVID patients.

Long COVID has perplexed scientists since the pandemic with its victims suffering from brain fogging, chronic fatigue and chest pain weeks and even months after the first symptoms of infection.

This very perplexity led Dr Ida Blystad, a neuroradiologist at Linköping University Hospital and a researcher affiliated with the Department of Health, to search for yet untried ways to see what goes on under the hood with patients suffering from the condition.

There have been numerous prior investigations into persistent issues following COVID-19 that have employed MRI brain scanning. While these studies have identified disparities in comparison to healthy brains, these distinctions are not exclusive to COVID-19.

In their recent study, featured in the journal Brain Communications, the researchers introduced advanced diffusion MRI, a new type of MR imaging. Their primary focus was on the brain's white matter, predominantly composed of nerve axons crucial for transmitting signals between different brain regions and the body.

Deneb Boito, a doctoral student at the Department of Biomedical Engineering at Linköping University, explains that diffusion MRI is an exceptionally sensitive technology capable of detecting changes in the organisation of nerve axons.

Linkoping University visualized the working of diffusion MRI as dark highway lit with a pearl string of car headlights.

Even though we can't see the road itself, we know it's there because cars move easily on it. In a similar way, doctors and researchers use diffusion MRI to understand how the brain is built on a tiny scale, it wrote.

The technology relies on the fact that water is everywhere in the brain and moves through the tissue following the easiest path. By measuring the movement of water molecules along these pathways, researchers can indirectly figure out the structure of the brain's neural pathways, just like we can indirectly tell there's a highway when we see many cars driving on it.

Diffusion MRI finds applications in healthcare, such as diagnosing strokes and planning brain surgeries.

In their study conducted at the Center for Medical Image Science and Visualization in Linköping, the researchers utilised the same advanced version of diffusion MRI.

They examined 16 men who had endured severe COVID-19 and were part of the Linköping COVID-19 Study (LinCos). Despite seven months passing, these individuals still experienced persistent symptoms.

A comparative analysis was performed with a group of healthy individuals devoid of post-COVID symptoms and no history of hospitalisation for COVID. The participants underwent brain examinations using both conventional MRI and diffusion MRI.

The results indicated disparities in the white matter structure of the brain between the two groups, suggesting a potential link to the neurological issues observed in those who suffered from severe COVID-19.

However, the researchers exercise caution in drawing definitive conclusions due to the study's limited sample size. They argued that diffusion MRI measures the brain's microstructure rather than its functionality and advocated the use of more advanced MRI technology beyond conventional MRI.