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.