CHEST CT USAGE IN COVID-19 PNEUMONIA: MULTICENTER STUDY ON RADIATION DOSES AND DIAGNOSTIC QUALITY IN BRAZIL

Abstract

We assessed variations in chest CT usage, radiation dose and image quality in COVID-19 pneumonia. Our study included all chest CT exams performed in 533 patients from 6 healthcare sites from Brazil. We recorded patients' age, gender and body weight and the information number of CT exams per patient, scan parameters and radiation doses (volume CT dose index-CTDIvol and dose length product-DLP). Six radiologists assessed all chest CT exams for the type of pulmonary findings and classified CT appearance of COVID-19 pneumonia as typical, indeterminate, atypical or negative. In addition, each CT was assessed for diagnostic quality (optimal or suboptimal) and presence of artefacts. Artefacts were frequent (367/841), often related to respiratory motion (344/367 chest CT exams with artefacts) and resulted in suboptimal evaluation in mid-to-lower lungs (176/344) or the entire lung (31/344). There were substantial differences in CT usage, patient weight, CTDIvol and DLP across the participating sites.

Figure 1

Box and whisker plots of median and interquartile ranges CTDI_vol (A) and DLP (B) for chest CT with optimal and suboptimal image quality. There were significant statistical differences in CTDI_vol (P = 0.014) but not in DLP (P = 0.078) for patients with optimal and suboptimal diagnostic quality. Weights of patients with suboptimal evaluation of entire lungs (median weight 70 kg, IQR 25 kg) were significantly lower than those with optimal evaluation (median weight 83 kg, IQR 30 kg) (P < 0.001).

Figure 2

Box and whisker plots summarize the median and interquartile ranges for CTDI_vol (A) and DLP (B) associated with chest CT exams with and without artefacts. There was no significant difference in weights (median weights 80–90 kg) of patients with and without artefacts.