Diagnostic accuracy of lung ultrasound for SARS-CoV-2: a retrospective cohort study

Abstract

Background As medical infrastructures are strained by SARS-CoV-2, rapid and accurate screening tools are essential. In portions of the world, reverse transcription polymerase chain reaction (RT-PCR) testing remains slow and in limited supply, and computed tomography is expensive, inefficient, and involves exposure to ionizing radiation. Multiple studies evaluating the efficiency of lung point-of-care ultrasound (POCUS) have been published recently, but include relatively small cohorts and often focus on characteristics associated with severe illness rather than screening efficacy. This study utilizes a retrospective cohort to evaluate the test characteristics (sensitivity, specificity, likelihood ratios, predictive values) of lung POCUS in the diagnosis of SARS-CoV-2, and to determine lung score cutoffs that maximize performance for use as a screening tool. Results Lung POCUS examinations had sensitivity 86%, specificity 71.6%, NPV 81.7%, and PPV 77.7%. The Lung Ultrasound Score had an area under the curve of 0.84 (95% CI 0.78, 0.90). When including only complete examinations visualizing 12 lung fields, lung POCUS had sensitivity 90.9% and specificity 75.6%, with NPV 87.2% and PPV 82.0% and an area under the curve of 0.89 (95% CI 0.83, 0.96). Lung POCUS was less accurate in patients with a history of interstitial lung disease, severe emphysema, and heart failure. Conclusions When applied in the appropriate patient population, lung POCUS is an inexpensive and reliable tool for rapid screening and diagnosis of SARS-CoV-2 in symptomatic patients with influenza-like illness. Adoption of lung POCUS screening for SARS-CoV-2 may identify patients who do not require additional testing and reduce the need for RT-PCR testing in resource-limited environments and during surge periods.

Mini-COVIDNet: Efficient Lightweight Deep Neural Network for Ultrasound Based Point-of-Care Detection of COVID-19

“…The US imaging can be performed daily for patients having severe infection of the lungs due to COVID-19 for better management [16], [17]. The recent work [18] utilizes POCUS for diagnosis of COVID-19 and was found to be very effective for rapid screening as well as diagnosis of COVID-19 in symptomatic patients. It was also concluded that lung POCUS was not very accurate for patients having a history of heart failure, severe emphysema, and interstitial lung disease [18].…”

“…The recent work [18] utilizes POCUS for diagnosis of COVID-19 and was found to be very effective for rapid screening as well as diagnosis of COVID-19 in symptomatic patients. It was also concluded that lung POCUS was not very accurate for patients having a history of heart failure, severe emphysema, and interstitial lung disease [18]. The availability and use of POCUS screening helped in the identification of symptomatic patients having COVID-19 and does not require performing the RT-PCR test in the resource-constrained settings and during peak periods of a surge in COVID-19 [18].…”

“…It was also concluded that lung POCUS was not very accurate for patients having a history of heart failure, severe emphysema, and interstitial lung disease [18]. The availability and use of POCUS screening helped in the identification of symptomatic patients having COVID-19 and does not require performing the RT-PCR test in the resource-constrained settings and during peak periods of a surge in COVID-19 [18]. In [19], it was suggested to use positive US signs as markers for identification of persons having COVID-19 unless otherwise proven negative by RT-PCR and suggested the possibility of a classification system based on US images (US-COVID-CORADS).…”

Diagnostic accuracy of point-of-care lung ultrasound for COVID-19: A systematic review and meta-analysis

“…Unsurprisingly those who tested positive on RT-PCR had higher scores (optimal cut-off scores are shown in Table 1). (25,26). It was also demonstrated that complete (12-zone) studies were 5% more sensitive and 4% more specific than less thorough studies.…”

“…Brenner et al, showed that when only complete 12-zone studies were included in their analysis, both sensitivity and specificity of LUS were improved. (26) The heterogenous criteria used to determine whether a positive LUS may also have affected the results of the various. Various thresholds were used for ruling in this diagnosis, ranging from any B lines to a minimum number of affected zones to a minimum severity score.…”