Digital tomosynthesis improves chest radiograph accuracy and reduces microbiological false negatives in COVID-19 diagnosis.

PURPOSE: Diagnosing pneumonia by radiograph is improvable. We aimed (a) to compare radiograph and digital thoracic tomosynthesis (DTT) performances and agreement for COVID-19 pneumonia diagnosis, and (b) to assess the DTT ability for COVID-19 diagnosis when polymerase chain reaction (PCR) and radiograph are negative. METHODS: Two emergency radiologists with 11 (ER1) and 14 experience-years (ER2) retrospectively evaluated radiograph and DTT images acquired simultaneously in consecutively clinically suspected COVID-19 pneumonia patients in March 2020-January 2021. Considering PCR and/or serology as reference standard, DTT and radiograph diagnostic performance and interobserver agreement, and DTT contributions in unequivocal, equivocal, and absent radiograph opacities were analysed by the area under the curve (AUC), Cohen's Kappa, Mc-Nemar's and Wilcoxon tests. RESULTS: We recruited 480 patients (49 ± 15 years, 277 female). DTT increased ER1 (from 0.76, CI95% 0.7-0.8 to 0.79, CI95% 0.7-0.8; P=.04) and ER2 (from 0.77 CI95% 0.7-0.8 to 0.80 CI95% 0.8-0.8, P=.02) radiograph-AUCs, sensitivity, specificity, predictive values, and positive likelihood ratio. In false negative microbiological cases, DTT suggested COVID-19 pneumonia in 13% (4/30; P=.052, ER1) and 20% (6/30; P=.020, ER2) more than radiograph. DTT showed new or larger opacities in 33-47% of cases with unequivocal opacities in radiograph, new opacities in 2-6% of normal radiographs and reduced equivocal opacities by 13-16%. Kappa increased from 0.64 (CI95% 0.6-0.8) to 0.7 (CI95% 0.7-0.8) for COVID-19 pneumonia probability, and from 0.69 (CI95% 0.6-0.7) to 0.76 (CI95% 0.7-0.8) for pneumonic extension. CONCLUSION: DTT improves radiograph performance and agreement for COVID-19 pneumonia diagnosis and reduces PCR false negatives.

Radiology departments as COVID-19 entry-door might improve healthcare efficacy and efficiency, and emergency department safety.

BACKGROUND: Possible COVID-19 pneumonia patients (ppCOVID-19) generally overwhelmed emergency departments (EDs) during the first COVID-19 wave. Home-confinement and primary-care phone follow-up was the first-level regional policy for preventing EDs to collapse. But when X-rays were needed, the traditional outpatient workflow at the radiology department was inefficient and potential interpersonal infections were of concern. We aimed to assess the efficiency of a primary-care high-resolution radiology service (pcHRRS) for ppCOVID-19 in terms of time at hospital and decision's reliability. METHODS: We assessed 849 consecutive ppCOVID-19 patients, 418 through the pcHRRS (home-confined ppCOVID-19 with negative-group 1- and positive-group 2-X-rays) and 431 arriving with respiratory symptoms to the ED by themselves (group 3). The pcHRRS provided X-rays and oximetry in an only-one-patient agenda. Radiologists made next-step decisions (group 1: pneumonia negative, home-confinement follow-up; group 2: pneumonia positive, ED assessment) according to X-ray results. We used ANOVA and Bonferroni correction, Student T, Chi2 tests to analyse changes in the ED workload, time-to-decision differences between groups, potential delays in patients acceding through the ED, and pcHRRS performance for deciding admission. RESULTS: The pcHRRS halved ED respiratory patients (49.2%), allowed faster decisions (group 1 vs. home-discharged group 2 and group 3 patients: 0:41 ± 1:05 h; 3:36 ± 2:58 h; 3:50 ± 3:16 h; group 1 vs. all group 2 and group 3 patients: 0:41 ± 1:05 h; 5.25 ± 3.08; 5:36 ± 4:36 h; group 2 vs. group 3 admitted patients: 5:27 ± 3:08 h vs. 7:42 ± 5:02 h; all p < 0.001) and prompted admission (84/93, 90.3%) while maintaining time response for ED patients. CONCLUSIONS: Our pcHRRS may be a more efficient entry-door for ppCOVID-19 by decreasing ED patients and making expedited decisions while guaranteeing social distance.