# Post COVID-19 condition is associated with altered regional cerebral blood volume as revealed by dynamic susceptibility contrast MRI

## TL;DR

This study finds that people with post-COVID-19 condition have reduced blood volume in certain brain regions, as seen through MRI scans.

## Contribution

The study reveals altered cerebral blood volume in post-COVID-19 condition using DSC MRI, providing new insights into cerebrovascular changes.

## Key findings

- PCC group showed decreased regional cerebral blood volume in multiple brain regions.
- Cerebrovascular alterations were observed months after initial illness in PCC individuals.
- rCBF differences were less pronounced and did not reach high probability thresholds.

## Abstract

Coronavirus disease 2019 (COVID-19) has been associated with central nervous system dysfunction implicating cerebrovascular and neurovascular units, as reflected in lower regional cerebral blood flow among non-hospitalized individuals that experienced post COVID-19 condition (PCC). This study investigates whether PCC is associated with altered regional cerebral blood volume assessed using Dynamic Susceptibility Contrast (DSC) Magnetic Resonance Imaging (MRI). The comparison control group are individuals without PCC who previously experienced cold or flu-like symptoms, or COVID-19.

Fifty-seven participants were recruited: 36 with PCC (mean age: 42.7, standard deviation: 10.4, 26 females) and 21 controls (mean age: 41.6, standard deviation: 14.7, 13 females). T2*-weighted DSC MRI was performed at 3 Tesla to image the first passage of the bolus. A total of 22 regions of interest (ROIs) were considered. Group differences in DSC-derived cerebral blood volume (rCBV) and cerebral blood flow (rCBF) were evaluated using Bayesian regression, providing median group differences, highest density interval (HDI), and the probability of direction (PD) estimates.

The two groups (PCC and controls) were matched for age, sex, days from symptom onset, and number of previous vaccines, but had different degrees of self-report illness severity. The rCBV analysis showed median group differences (range: −0.05 to −0.13), with PD > 0.90, indicating a high probability of decreased rCBV in the PCC group, involving the superior frontal gyrus, thalamus, paracentral lobule, cingulate gyrus, postcentral gyrus, middle frontal gyrus, inferior frontal gyrus, and superior temporal gyrus ROIs. By comparison, group differences in rCBF were muted and did not reach PD > 0.90.

We found group-level differences that were reflected by lower regional rCBV in PCC relative to controls. The imaging findings are suggestive of cerebrovascular alterations several months after the initial illness.