Typical CT features of COVID-19 pneumonia include bilateral lung involvement in form of ground-glass opacities, predominantly in peripheral posterior distribution with lower lung zone predilection. • Subpleural sparing and pleural effusion are seen approximately in one-fifth and onesixth of our COVID-19 cases respectively. • Consolidation, air-bronchograms, central lung involvement and pleural effusion on initial CT chest have prognostic value, seen significantly more in ICU admitted and expired cases. Summary statement: In the evaluation of initial CT chest features of 120 confirmed cases of COVID-19, certain findings are statistically more common in critically ill and expired patients after a short-term follow up including consolidation, air-bronchograms, crazy paving, central lung involvement, and pleural effusion.
Purpose
The increasing trend of chest CT utilization during the COVID-19 pandemic necessitates novel protocols with reduced dose and maintained diagnostic accuracy. We aimed to investigate the diagnostic accuracy of 30-mAs chest CT protocol in comparison with a 150-mAs standard-dose routine protocol for imaging of COVID-19 pneumonia.
Methods
Upon IRB approval, consecutive laboratory-confirmed positive COVID-19 patients aged 50 years or older who were referred for chest CT scan and had same-day normal CXR were invited to participate in this prospective study. First, a standard-dose chest CT scan (150 mAs) was performed. Only if typical COVID-19 pneumonia features were identified, then a low-dose CT (30 mAs) was done immediately. Diagnostic accuracy of low-dose and standard-dose CT in the detection of typical COVID-19 pneumonia features were compared.
Results
Twenty patients with a mean age of 64.20 ± 13.8 were enrolled in the study. There was excellent intrareader agreement in detecting typical findings of COVID-19 pneumonia between low-dose and standard-dose (intraclass correlation coefficient [ICC] = 0.98–0.99,
P
values < 0.001 all readers). The mean effective dose values in standard- and low-dose groups were 6.60 ± 1.47 and 1.80 ± 0.42 mSv, respectively. Also, absolute cancer risk per mean cumulative effective dose values obtained from the standard- and low-dose CT examinations were 2.71 × 10
−4
and 0.74 × 10
−4
, respectively.
Conclusions
According to our study, it was found that proposed low-dose CT chest protocol is reliable in detecting COVID-19 pneumonia in daily practice with significant reduction in radiation dose and estimated cancer risk.
Highlights
CT severity score is a predictor of mortality in nonelderly COVID-19 pneumonia.
CT severity score more than 7.5 has a sensitivity of 83 % in predicting mortality.
The extent of disease should be relayed to the clinician for higher care priorities.
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