COVID-19 S: A new proposal for diagnosis and structured reporting of COVID-19 on computed tomography imaging

Diagn Interv Radiol. 2020 Jul;26(4):315-322. doi: 10.5152/dir.2020.20351.


Purpose: Because of the widespread use of CT in the diagnosis of COVID 19, indeterminate presentations such as single, few or unilateral lesions amount to a considerable number. We aimed to develop a new classification and structured reporting system on CT imaging (COVID-19 S) that would facilitate the diagnosis of COVID-19 in the most accurate way.

Methods: Our retrospective cohort included 803 patients with a chest CT scan upon suspicion of COVID 19. The patients' history, physical examination, CT findings, RT PCR, and other laboratory test results were reviewed, and a final diagnosis was made as COVID 19 or non-COVID 19. Chest CT scans were classified according to the COVID 19 S CT diagnosis criteria. Cohen's kappa analysis was used.

Results: Final clinical diagnosis was COVID-19 in 98 patients (12%). According to the COVID-19 S CT diagnosis criteria, the number of patients in the normal, compatible with COVID 19, indeterminate and alternative diagnosis groups were 581 (72.3%), 97 (12.1%), 16 (2.0%) and 109 (13.6%). When the indeterminate group was combined with the group compatible with COVID 19, the sensitivity and specificity of COVID-19 S were 99.0% and 87.1%, with 85.8% positive predictive value (PPV) and 99.1% negative predictive value (NPV). When the indeterminate group was combined with the alternative diagnosis group, the sensitivity and specificity of COVID-19 S were 93.9% and 96.0%, with 94.8% PPV and 95.2% NPV.

Conclusion: COVID-19 S CT classification system may meet the needs of radiologists in distinguishing COVID-19 from pneumonia of other etiologies and help optimize patient management and disease control in this pandemic by the use of structured reporting.

MeSH terms

  • Adult
  • Betacoronavirus / genetics*
  • Betacoronavirus / isolation & purification
  • COVID-19
  • Cohort Studies
  • Coronavirus Infections / diagnostic imaging*
  • Coronavirus Infections / epidemiology
  • Coronavirus Infections / prevention & control
  • Coronavirus Infections / virology
  • Diagnosis, Differential
  • Diagnostic Tests, Routine / methods
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pandemics / prevention & control
  • Pneumonia / diagnostic imaging*
  • Pneumonia / etiology
  • Pneumonia / pathology
  • Pneumonia, Viral / diagnostic imaging*
  • Pneumonia, Viral / epidemiology
  • Pneumonia, Viral / prevention & control
  • Pneumonia, Viral / virology
  • Predictive Value of Tests
  • Radiologists / statistics & numerical data
  • Retrospective Studies
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • SARS-CoV-2
  • Sensitivity and Specificity
  • Thorax / diagnostic imaging*
  • Tomography, X-Ray Computed / classification*
  • Tomography, X-Ray Computed / methods
  • Turkey / epidemiology