Chest CT outperforms RT-PCR for COVID-19 diagnosis

  • Ai T, et al
  • Radiology
  • 27 Feb 2020

  • curated by Liz Scherer
  • Clinical Essentials
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Takeaway

  • Chest CT has high sensitivity for rapid COVID-19 diagnosis compared with reverse-transcription-PCR (RT-PCR) assay testing.

Why this matters

  •   Consider chest CT for initial COVID-19 screening, evaluation, and follow-up to ensure timely diagnosis and subsequent isolation and treatment, as needed.

Key results

  • 1014 patients, mean age 51 + 15 years, 46% (467/1014) male.
  • RT-PCR positive rate: 59% (56%-62%).
  • Chest CT positive rate: 88% (86%-90%).
  • Chest CT: 97% sensitivity (95%-98%), 25% specificity (22%-30%).
  • CT chest accuracy: 68% (65%-70%).
  • Positive predictive value:
    • 72% in patients > 60 years (P=.001);
    • 62% in those P=.009).
  • Primary chest CT findings: ground-glass opacity (46%), consolidation (50%).
  • 308 patients with negative RT-PCR had chest CT images suggestive of COVID-19:
    • 48% were considered highly likely, 33% probable, and 19% uncertain.
  • Subgroup of negative-to-positive RT-PCR results:
    • 67% (10/15) of cases had positive chest CT vs negative RT-PCR;
    • 93% (14/15) had imaging with typical COVID-19 features before or parallel to initial positive RT-PCR (median interval, 8 days; range, 0-21 days).

Study design

  • Case investigation of diagnostic chest CT value, consistency vs initial, serial RT-PCR testing in Chinese patients, January 6-February 6, 2020.
  • Funding: None.

Limitations

  • Potentially overestimated chest CT sensitivity, underestimated specificity.
  • Limited laboratory, clinical data.