CT Volumes from 2,398 Radiology Practices in the United States: A Real-Time Indicator of the Effect of COVID-19 on Routine Care, January to September 2020.

PURPOSE: To determine the effect of coronavirus disease 2019 (COVID-19) on CT volumes in the United States during and after the first wave of the pandemic. METHODS: CT volumes from 2,398 US radiology practices participating in the ACR Dose Index Registry from January 1, 2020, to September 30, 2020, were analyzed. Data were compared to projected CT volumes using 2019 normative data and analyzed with respect to time since government orders, population-normalized positive COVID-19 tests, and attributed deaths. Data were stratified by state population density, unemployment status, and race. RESULTS: There were 16,198,830 CT examinations (2,398 practices). Volume nadir occurred an average of 32 days after each state-of-emergency declaration and 12 days after each stay-at-home order. At nadir, the projected volume loss was 38,043 CTs per day (of 71,626 CTs per day; 53% reduction). Over the entire study period, there were 3,689,874 fewer CT examinations performed than predicted (of 18,947,969; 19% reduction). There was less reduction in states with smaller population density (15% [169,378 of 1,142,247; quartile 1] versus 21% [1,894,152 of 9,140,689; quartile 4]) and less reduction in states with a lower insured unemployed proportion (13% [279,331 of 2,071,251; quartile 1] versus 23% [1,753,521 of 7,496,443; quartile 4]). By September 30, CT volume had returned to 84% (59,856 of 71,321) of predicted; recovery of CT volume occurred as positive COVID-19 tests rose and deaths were in decline. CONCLUSION: COVID-19 substantially reduced US CT volume, reflecting delayed and deferred care, especially in states with greater unemployment. Partial volume recovery occurred despite rising positive COVID-19 tests.