MRIs reveal brain microstructure changes in people with long COVID
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Key takeaways:
- A novel MRI technique revealed brain microstructure changes after COVID-19 and linked them to long COVID symptoms.
- The scans revealed changes in all patients with COVID-19, regardless of post-COVID conditions.
A novel MRI technique showed brain microstructure changes in people who have had COVID-19, and it traced long COVID symptoms to specific networks of the brain, according to a study.
The study, which will be presented next week at the Radiological Society of North America’s annual meeting, revealed differences between brain alterations in people with long COVID and those who fully recovered after acute infection.
A CDC survey conducted earlier this year found that more than one in 20 adults in the United States has experienced a long COVID symptom — including neurocognitive deficits, disturbed olfaction and fatigue — and that the risk for a post-COVID condition (PCC) can persist for as long as 2 years after infection.
Previous studies have suggested that SARS-CoV-2 infection can affect brain function, in addition to the function of other organs. One study published in October suggested that neurocognitive symptoms of long COVID are associated with persistent viral infection in the gut, causing a depletion of serotonin levels.
In the most recent analysis, Alexander Rau, MD, a resident in the departments of neuroradiology and diagnostic and interventional radiology at University Hospital Freiburg in Germany, and colleagues used the novel MRI technique diffusion microstructure imaging (DMI), which looks at the movement of water molecules in tissues, revealing how the molecules move and at what speeds, to detect small changes to the brain that conventional MRI cannot detect.
“We aimed at revealing the microstructural signature of this pathology in the brain,” Rau told Healio. “For this, we chose DMI as it is a promising technique to approximate the brain tissue’s microstructure in a noninvasive way, and it is well suited to detect pathological alterations.”
Rau and colleagues compared DMI findings from 89 patients with long COVID, 47 control patients who had never experienced a SARS-CoV-2 infection and an additional 38 controls who had COVID-19 but reported no long COVID symptoms.
Among the participants with long COVID, 41% had cognitive impairments, 73% had olfactory impairments and 78% experienced fatigue, according to the study. Additionally, 53% could not return to previous levels of work or personal independence because of long COVID symptoms.
The findings from all three groups revealed a volume-shift from the extraneurite compartment into the free-water fraction for the brain’s gray matter that was linked to the severity of the initial SARS-CoV-2 infection for participants with long COVID and those without long COVID, according to the study.
The researchers further noted that symptom-specific microstructure networks emerged that were “significantly correlated” with cognitive impairments, olfactory impairments and fatigue.
Overall, the DMI data revealed “long-lasting” brain microstructure changes in all participants who had COVID-19, although different patterns of changes were seen among those who did and did not experience long COVID. Rau said the effects seen on DMI were not big enough to derive a biomarker that could distinguish patients with long COVID and those without it, however.
He said the study provided insights into the neuropathological basis of long COVID and that these changes can, in fact, be detected. Moreover, the correlation of specific brain networks to individual long-COVID symptoms supports the use of the DMI technique.
“Further research is required to identify biomarkers predicting the disease course and to identify those at risk for developing [long COVID] and other postinfectious conditions,” Rau said.
References:
- Novel MRI reveals brain changes in long COVID patients. https://press.rsna.org/timssnet/media/pressreleases/14_pr_target.cfm?id=2481. Published Nov. 22, 2023. Accessed Nov. 22, 2023.
- Rau A, et al. Cerebral microstructural alterations in post-COVID conditions are related to cognitive impairment, olfactory dysfunction and fatigue. Presented at: Radiological Society of North America annual meeting; Nov. 26-30, 2023; Chicago.
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Rau A, et al. Cerebral microstructural alterations in post-COVID-conditions are related to cognitive impairment, olfactory dysfunction and fatigue; Presented at: Radiological Society of North America annual meeting; Nov. 26-30, 2023; Chicago.
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