Diffusion tensor imaging features of white matter pathways in the brain after COVID-19 infection.

Purpose: To determine whether there is a difference in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values in white matter pathways in the subacute period after COVID-19 infection and to evaluate the correlation between diffusion tensor imaging (DTI) metrics and laboratory findings.

Material and methods: The study included 64 healthy controls and 91 patients. Patients were classified as group 1 (all patients, n = 91), group 2 (outpatients, n = 58), or group 3 (inpatients, n = 33). The ADC and FA values were calculated from 10 distinct neuroanatomic localizations; DTI values were compared between groups.

Results: Decreased FA values in the cingulum, corpus callosum splenium and genu (CCS-CCG), forceps major, inferior fronto-occipital fasciculus (IFOF), and middle cerebellar peduncle (MCP) observed in group 1 compared with the control group. Group 1 showed elevated ADC values in CCG. Lower FA and higher ADC values in CCG were shown in group 3. The FA values for CCS, IFOF, and MCP in group 3 were lower than those in the control group. Group 3 had the highest ADC values in the CCS. Additionally, the FA values of the CCG were lower in group 3 than in group 2. Oxygen saturation levels and FA values in the CCG and SFOF exhibited a positive correlation.

Conclusion: We speculate that DTI changes in white matter pathways may be associated with axonal damage and demyelination due to impaired white matter integrity following COVID-19 infection during the subacute period.

Clinical significance: Our study showed with DTI findings that there is microstructural damage in white matter pathways in the subacute period of COVID-19 infection and that this damage is related to oxygen saturation levels. Many studies in the literature show that microstructural damage in white matter pathways can lead to clinical neurocognitive dysfunction. We suggest that these cases require more comprehensive studies investigating whether chronic white matter damage is reversible and examining its relationship with neurocognitive dysfunctions in the future.

Main points: Neurological involvement is not rare in COVID-19 infection. We examined various white matter pathways with DTI during the subacute period of COVID-19 infection. We showed changes in DTI parameters indicating a decrease in white matter integrity and microstructural damage in the subacute period follow-up of cases with COVID-19. We found that there was a positive correlation between oxygen saturation levels and decreased FA values in white matter tracts.