Chest x-ray imaging score is associated with severity of COVID-19 pneumonia: the MBrixia score

Spatial resolution in existing chest x-ray (CXR)-based scoring systems for coronavirus disease 2019 (COVID-19) pneumonia is low, and should be increased for better representation of anatomy, and severity of lung involvement. An existing CXR-based system, the Brixia score, was modified to increase the spatial resolution, creating the MBrixia score. The MBrixia score is the sum, of a rule-based quantification of CXR severity on a scale of 0 to 3 in 12 anatomical zones in the lungs. The MBrixia score was applied to CXR images from COVID-19 patients at a single tertiary hospital in the period May 4th-June 5th, 2020. The relationship between MBrixia score, and level of respiratory support at the time of performed CXR imaging was investigated. 37 hospitalized COVID-19 patients with 290 CXRs were identified, 22 (59.5%) were admitted to the intensive care unit and 10 (27%) died during follow-up. In a Poisson regression using all 290 MBrixia scored CXRs, a higher MBrixia score was associated with a higher level of respiratory support at the time of performed CXR. The MBrixia score could potentially be valuable as a quantitative surrogate measurement of COVID-19 pneumonia severity, and future studies should investigate the score's validity and capabilities of predicting clinical outcomes.

Automated summary

The existing chest X-ray (CXR)-based scoring systems for COVID-19 pneumonia have low spatial resolution, which needs to be increased for better evaluation of lung anatomy and severity. In this study, the MBrixia score was developed by modifying the Brixia score to improve spatial resolution. The MBrixia score, based on a rule-based quantification of CXR severity in 12 anatomical zones, was applied to CXR images of COVID-19 patients. The results showed a positive correlation between the MBrixia score and the level of respiratory support at the time of CXR imaging. The MBrixia score has the potential to serve as a quantitative surrogate measurement of COVID-19 pneumonia severity, and further research should investigate its validity and predictive capabilities for clinical outcomes.