Diagnostic accuracy of chest CT for COVID-19 pneumonia in a resource-limited Gaza cohort: a retrospective study of 252 patients.

PURPOSE

The study aimed to evaluate the diagnostic accuracy of chest CT for COVID-19 pneumonia in resource-limited Gaza. It compared CT performance to RT-PCR and examined how CT severity scores and interobserver agreement influence diagnostic accuracy, reproducibility, and clinical utility for early detection and triage.

METHODS

A retrospective analysis was performed on 252 consecutive patients diagnosed with COVID-19 pneumonia between September 2020 and June 2021 at three major governmental hospitals across the Gaza Strip. Chest CT scans were compared to RT-PCR as the gold standard for diagnosis. CT severity scores were calculated using a 25-point system, and interobserver agreement was assessed using kappa statistics. Sensitivity, specificity, and predictive values were calculated for various threshold levels.

RESULTS

Among the 252 patients included in the study, the mean age was 56.81 ± 11.34 years, with 113 males and 139 females. The diagnostic sensitivity of chest CT was 91.4%, with a specificity of 76.4%. The highest accuracy was observed with a severity score threshold of ≥ 15, with a Youden index of 0.630. Interobserver agreement was excellent (kappa = 0.87) for ground-glass opacities and consolidation. The NPV was 71.2%, indicating the need for supplementary RT-PCR testing in low-prevalence cases.

CONCLUSION

Chest CT is a reliable diagnostic adjunct for COVID-19 pneumonia, especially in Gaza's severely resource-limited setting, where CT was more accessible than RT-PCR. A CT severity score threshold of ≥ 15 offers an optimal balance of sensitivity and specificity. These findings highlight the practical role of CT imaging in pandemic response in resource-constrained environments.