# Carotid Body Size on CT Angiography in Patients With COVID-19 Pneumonia

## TL;DR

This study found that carotid bodies are larger in patients with COVID-19 pneumonia compared to healthy individuals, suggesting possible effects of the disease on these oxygen-sensing structures.

## Contribution

The study is the first to use CT angiography to show carotid body enlargement in COVID-19 patients, linking it to potential sympathetic activation or viral infection.

## Key findings

- Carotid body area was significantly larger in COVID-19 patients (4.9 mm²) compared to controls (3.7 mm²).
- The enlargement may reflect activation of carotid body receptors due to low oxygen levels or sympathetic activity in COVID-19.
- Direct viral infection of carotid bodies is also a possible explanation for the observed enlargement.

## Abstract

Many pathophysiological theories have been expressed regarding increased sympathetic activity along with respiratory failure in patients with COVID-19 pneumonia. In addition, the carotid bodies, which are directly related to increased blood oxygen levels and sympathetic activity, are known to be very rich in the angiotensin-converting enzyme 2 (ACE2) receptor, which the COVID-19 causative virus uses to enter the cell. Therefore, the probability of carotid bodies being affected in patients with COVID-19 pneumonia is quite high. Carotid bodies can be visualized with contrast-enhanced CT angiography (CTA), and we aimed to visualize possible carotid body enlargement in COVID-19 patients with CTA.

We retrospectively evaluated patients who were hospitalized for COVID-19 pneumonia during the pandemic in our hospital and who had CTA examinations at least 3 months after treatment. We drew a Region of Interest (ROI) from the periphery of both carotid bodies and measured the area from the widest part. Similarly, measurements were taken in the control group without a history of COVID-19, and the results of the two groups were compared statistically.

We performed measurements on CTA images of 104 control subjects and 108 patients. The total carotid body area of the patients with COVID-19 pneumonia was 4.9 ± 3.7 mm2, and the carotid body area of the control group was 3.7 ± 2.4 mm2. In comparing the two groups, the carotid body area was found to be statistically significantly larger (p < 0.05) in patients with COVID-19 pneumonia.

The size of the carotid body was found to be larger in patients with COVID-19 pneumonia compared to the control group. This finding may indicate conditions that lead to the activation of carotid body chemo and baroreceptors, such as increased sympathetic activity and a decrease in blood oxygen pressure in patients with COVID-19 pneumonia. Apart from this, it may also be possible for the carotid body to be directly infected with the virus. More specific studies that shed light on this aspect are needed.