Lung ultrasonography in pregnant women during the COVID-19 pandemic: an interobserver agreement study among obstetricians

Medical Imaging in Pregnancy: Safety, Appropriate Utilization, and Alternative Modalities for Imaging Pregnant Patients

This article reviews the existing literature on diagnostic and medical imaging of pregnant women, the risks and safety measures of different medical imaging modalities, and alternative modalities for imaging pregnant patients. Different medical imaging modalities such as MRI, CT scan, ultrasound, nuclear medicine, and X-ray imaging help to evaluate women with recognized or unrecognized pregnancies and identify any underlying complications among pregnant patients. Fetuses are more sensitive to radiation and the effects of medical imaging as compared to adults since they have a rapidly developing cell system. During cell proliferation, migration, and differentiation, fetuses suffer greatly from imaging radiation since they are developing under a dynamic system. To ensure safety, pregnant women should discuss the benefits and risks of medical imaging with their physicians. In addition, radiologists should not perform any medical imaging procedure without the patient's consent, unless the patient cannot make any sound decision. Fetal risks of medical imaging include slow growth and development of the fetus, abortion, malformations, impaired brain function, abnormal childhood growth, and neurological development. Diagnostic imaging procedures are necessary when a condition that needs medical evaluation arises during pregnancy such as appendicitis.

Lung ultrasound versus chest computed tomography for pregnant inpatients with COVID-19

PURPOSE

To compare lung ultrasound (US) and computed tomography (CT) in the assessment of pregnant women with COVID-19.

METHODS

Prospective study comprising 39 pregnant inpatients with COVID-19 who underwent pulmonary assessment with CT and US with a maximum span of 48 h between the exams. The thorax was divided into 12 regions and assessed in terms of the following: the presence of B-lines (>2), coalescent B-lines, consolidation on US; presence of interlobular thickening, ground glass, consolidation on CT. The two methods were scored by adding up the scores from each thoracic region.

RESULTS

A significant correlation was found between the scores obtained by the two methods (rICC = 0.946; p < 0.001). They were moderately in agreement concerning the frequency of altered pulmonary regions (weighted kappa = 0.551). In US, a score over 15, coalescent B-lines, and consolidation were predictors of the need for oxygen, whereas the predictors in CT were a lung score over 16 and consolidation. The two methods, US (p < 0.001; AUC = 0.915) and CT (p < 0.001; AUC = 0.938), were fairly accurate in predicting the need for oxygen.

CONCLUSION

In pregnant women, lung US and chest CT are of similar accuracy in assessing lungs affected by COVID-19 and can predict the need for oxygen.

Review of Machine Learning in Lung Ultrasound in COVID-19 Pandemic

Ultrasound imaging of the lung has played an important role in managing patients with COVID-19-associated pneumonia and acute respiratory distress syndrome (ARDS). During the COVID-19 pandemic, lung ultrasound (LUS) or point-of-care ultrasound (POCUS) has been a popular diagnostic tool due to its unique imaging capability and logistical advantages over chest X-ray and CT. Pneumonia/ARDS is associated with the sonographic appearances of pleural line irregularities and B-line artefacts, which are caused by interstitial thickening and inflammation, and increase in number with severity. Artificial intelligence (AI), particularly machine learning, is increasingly used as a critical tool that assists clinicians in LUS image reading and COVID-19 decision making. We conducted a systematic review from academic databases (PubMed and Google Scholar) and preprints on arXiv or TechRxiv of the state-of-the-art machine learning technologies for LUS images in COVID-19 diagnosis. Openly accessible LUS datasets are listed. Various machine learning architectures have been employed to evaluate LUS and showed high performance. This paper will summarize the current development of AI for COVID-19 management and the outlook for emerging trends of combining AI-based LUS with robotics, telehealth, and other techniques.

Ultrasound findings of lung ultrasonography in COVID-19: A systematic review

PURPOSE

To identify the defining lung ultrasound (LUS) findings of COVID-19, and establish its association to the initial severity of the disease and prognostic outcomes.

METHOD

Systematic review was conducted according to the PRISMA guidelines. We queried PubMed, Embase, Web of Science, Cochrane Database and Scopus using the terms ((coronavirus) OR (covid-19) OR (sars AND cov AND 2) OR (2019-nCoV)) AND (("lung ultrasound") OR (LUS)), from 31st of December 2019 to 31st of January 2021. PCR-confirmed cases of SARS-CoV-2 infection, obtained from original studies with at least 10 participants 18 years old or older, were included. Risk of bias and applicability was evaluated with QUADAS-2.

RESULTS

We found 1333 articles, from which 66 articles were included, with a pooled population of 4687 patients. The most examined findings were at least 3 B-lines, confluent B-lines, subpleural consolidation, pleural effusion and bilateral or unilateral distribution. B-lines, its confluent presentation and pleural abnormalities are the most frequent findings. LUS score was higher in intensive care unit (ICU) patients and emergency department (ED), and it was associated with a higher risk of developing unfavorable outcomes (death, ICU admission or need for mechanical ventilation). LUS findings and/or the LUS score had a good negative predictive value in the diagnosis of COVID-19 compared to RT-PCR.

CONCLUSIONS

The most frequent ultrasound findings of COVID-19 are B-lines and pleural abnormalities. High LUS score is associated with developing unfavorable outcomes. The inclusion of pleural effusion in the LUS score and the standardisation of the imaging protocol in COVID-19 LUS remains to be defined.

Lung Ultrasound Severity Index: Development and Usefulness in Patients with Suspected SARS-Cov-2 Pneumonia-A Prospective Study

Coronavirus disease 2019 (COVID-19) has spread across the world with a strong impact on populations and health systems. Lung ultrasound is increasingly employed in clinical practice but a standard approach and data on the accuracy of lung ultrasound are still needed. Our study's objective was to evaluate lung ultrasound diagnostic and prognostic characteristics in patients with suspected COVID-19. We conducted a monocentric, prospective, observational study. Patients with respiratory distress and suspected COVID-19 consecutively admitted to the Emergency Medicine Unit were enrolled. Lung ultrasound examinations were performed blindly to clinical data. Outcomes were diagnosis of COVID-19 pneumonia and in-hospital mortality. One hundred fifty-nine patients were included in our study; 66% were males and 63.5% had a final diagnosis of COVID-19. COVID-19 patients had a higher mortality rate (18.8% vs. 6.9%, p = 0.04) and Lung Ultrasound Severity Index (16.14 [8.71] vs. 10.08 [8.92], p < 0.001) compared with non-COVID-19 patients. This model proved able to distinguish between positive and negative cases with an area under the receiver operating characteristic (AUROC) equal to 0.72 (95% confidence interval [CI]: 0.64-0.78) and to predict in-hospital mortality with an AUROC equal to 0.81 (95% CI: 0.74-0.86) in the whole population and an AUROC equal to 0.76 (95% CI: 0.66-0.84) in COVID-19 patients. The Lung Ultrasound Severity Index can be a useful tool in diagnosing COVID-19 in patients with a high pretest probability of having the disease and to identify, among them, those with a worse prognosis.

The role of PoCUS in the assessment of COVID-19 patients

The Coronavirus disease 19 (COVID-19) pandemic has increased the burden of stress on the global healthcare system in 2020. Point of care ultrasound (PoCUS) is used effectively in the management of pulmonary, cardiac and vascular pathologies. POCUS is the use of traditional ultrasound imaging techniques in a focused binary manner to answer a specific set of clinical questions. This is an imaging technique that delivers no radiation, is inexpensive, ultraportable and provides results instantaneously to the physician operator at the bedside. In regard to the pandemic, PoCUS has played a significant adjunctive role in the diagnosis and management of co-morbidities associated with COVID-19. PoCUS also offers an alternative method to image obstetric patients and the pediatric population safely in accordance with the ALARA principle. Finally, there have been numerous PoCUS protocols describing the effective use of this technology during the COVID-19 pandemic.

Application of quantitative lung ultrasound instead of CT for monitoring COVID-19 pneumonia in pregnant women: a single-center retrospective study

BACKGROUND

Computed tomography (CT) is the preferred imaging technique for the evaluation of COVID-19 pneumonia. However, it is not suitable as a monitoring tool for pregnant women because of the risk of ionizing radiation damage to the fetus as well as the possible infection of others. In this study, we explored the value of bedside lung ultrasound (LUS) as an alternative to CT for the detection and monitoring of lung involvement in pregnant women with COVID-19.

METHODS

Clinical and LUS data of 39 pregnant women with COVID-19 were retrospectively reviewed. All LUS and CT images were analyzed to summarize the findings and calculate LUS scores and CT scores for each patient. LUS findings were compared with CT, and correlation between LUS scores and CT scores was evaluated.

RESULTS

Among the 39 pregnant women, there were 6 mild-type cases, 29 common-type cases, 4 severe-type cases, and no critical-type cases. The most common LUS findings of COVID-19 pneumonia in pregnant women were various grades of multiple B-lines (84.6%), thickened and irregular pleural lines (71.8%), pleural effusion (61.5%) and small multifocal consolidation limited to the subpleural space (35.9%). The mean LUS score at admission was 0 points in mild-type cases, 10.6 points in common-type cases and 15.3 points in severe-type cases (P < 0.01). The correlation between LUS scores and CT was 0.793. All patients were clinically cured and each underwent an average of three LUS follow-ups during hospitalization. The mean LUS score at discharge was 5.6 points lower than that at admission. The consistency of LUS and chest CT during follow-up was 0.652.

CONCLUSIONS

Quantitative LUS scoring can effectively instead of CT for detecting and monitoring of COVID-19 pneumonia in pregnant women and protect fetuses from the risk of ionizing radiation.

Diagnostic value of lung ultrasound in COVID-19: systematic review and meta-analysis

BACKGROUND:Effective and safe tools assisting triage decisions for COVID-19 patients could optimize the pressure on the healthcare system. COVID-19 often has respiratory manifestations, and medical imaging techniques provide an opportunity to assess the diseases severity. AIMS:To estimate the sensitivity and specificity of lung ultrasound for different degrees of pulmonary involvement in COVID-19 patients by a systematic review of English articles using PubMed and Google Scholar databases. Search terms included lung ultrasound, chest ultrasound, thoracic ultrasound, ultrasonography, COVID-19, SARS-CoV-2, coronavirus, diagnosis, diagnostic value, specificity, and sensitivity. Only studies addressing lung ultrasound diagnostic accuracy for patients with suspected COVID-19 using thoracic computed tomography, reverse transcription polymerase chain reaction, or laboratory data as a reference standard were included. Independent extraction of articles was performed by two authors using predefined data fields with subsequent assessment of study quality indicators. The random-effect model was used to analyze and pool lung ultrasound sensitivity and specificity across the included studies. Sixteen studies met our inclusion criteria, but only three of them divided patients into distinct and defined groups depending on the disease severity. We used the remaining studies data to assess the secondary outcomes: the values of sensitivity and specificity of lung ultrasound for COVID-19 regardless of the patients clinical status. Heterogeneity for primary and secondary outcomes was observed that remained when pooling for different scenarios (screening, assessing severity) and cohorts of participants. Lung ultrasound had the highest accuracy for confirmed COVID-19 patients with severe disease (sensitivity 87.6% 12.3%, specificity 80.5% 7.1%), and the lowest accuracy for the patients with mild disease (sensitivity 72.8% 7.1%, specificity 74.3% 2.7%). CONCLUSIONS:Lung ultrasound can be used in patients with confirmed COVID-19 to detect serious damage to the lung tissue. The diagnostic value of the method for assessing mild and moderate lung lesions is relatively low.

New Insight into Laboratory Tests and Imaging Modalities for Fast and Accurate Diagnosis of COVID-19: Alternative Suggestions for Routine RT-PCR and CT-A Literature Review

The globally inimitable and unremitting outbreak of COVID-19 infection confirmed the emergency need for critical detection of human coronavirus infections. Laboratory diagnostic tests and imaging modalities are two test groups used for the detection of COVID-19. Nowadays, real-time polymerase chain reaction (RT-PCR) and computed tomography (CT) have been frequently utilized in the clinic. Some limitations that confront with these tests are false-negative results, tests redone for follow-up procedure, high cost, and unable to do for all patients. To overcome these limitations, modified and alternative tests must be considered. Among these tests, RdRp/Hel RT-PCR assay had the lowest diagnostic limitation and highest sensitivity and specificity for the detection of SARS-CoV-2 RNA in both respiratory tract and nonrespiratory tract clinical specimens. On the other hand, lung ultrasound (LUS) and magnetic resonance imaging (MRI) are CT-alternative imaging modalities for the management, screening, and follow-up of COVID-19 patients.

Outcomes of universal SARS-CoV-2 testing program in pregnant women admitted to hospital and the adjuvant role of lung ultrasound in screening: a prospective cohort study

BACKGROUND

The emerging evidence for the asymptomatic carriers of SARS-CoV-2 infection emphasized the critical need for universal screening of pregnant women.

OBJECTIVES

This study aimed to present the prevalence of overall and asymptomatic SARS-CoV-2 infection rates in pregnant women admitted to the hospital, and assess the diagnostic accuracy of maternal symptoms and lung ultrasound (LUS) findings in detecting the infection.

PATIENTS AND METHODS

This prospective cohort study was conducted at a single tertiary center in Istanbul, Turkey, for a month period starting from 27 April 2020. Women with a confirmed pregnancy regardless of the gestational week admitted to the obstetric unit with any indication were consecutively underwent LUS and PCR testing for SARS-CoV-2.

RESULTS

A total of 296 patients were included for the final analysis. The universal screening strategy diagnosed 23 pregnant women (7.77%) with SARS-CoV-2 infection. The rate of symptomatic and asymptomatic patients diagnosed with SARS-CoV-2 was found as 3.72% (n = 11) and 4.05% (n = 12), respectively. Four of nine women who underwent a second testing for SARS-CoV-2 upon abnormal LUS findings were found positive eventually (17.4%, n = 4/23). The asymptomatic pregnant women with LUS score of 1 and those with normal LUS findings were considered as likely to be normal. Symptomatic patients with LUS score of 1 and those with score of 2 or 3 were considered as abnormal. On a secondary diagnostic performance analysis, the positive predictive value and the sensitivity were found as 44% and 47.8% for the triage based on maternal symptoms and, 82.3% and 60.9% for the triage based on LUS, respectively.

CONCLUSION

A one-month trial period of universal testing for SARS-CoV-2 infection with RT-PCR in pregnant women who admitted to the hospital showed an overall and asymptomatic infection diagnose rate of 7.77% and 4%, respectively. Using lung ultrasound was found more predictive in detecting the infection than the use of symptomatology solely.

How to perform and interpret the lung ultrasound by the obstetricians in pregnant women during the SARS-CoV-2 pandemic

OBJECTIVE

Evidence for the use of lung ultrasound scan (LUS) examinations in coronavirus 2019 pneumonia is rapidly growing. The safe and non-ionizing nature of LUS drew attention, particularly for pregnant women. This study aimed to contribute to the interpretation of LUS findings in pregnant women for the obstetricians.

MATERIALS AND METHODS

LUS was performed to pregnant women suspected of or diagnosed as having Severe Acute Respiratory syndrome coronavirus-2 (SARS-CoV-2) in the first 24 hours of admission. Fourteen areas (3 posterior, 2 lateral, and 2 anterior) were scanned per patient for at least 10 seconds along the indicated anatomical landmarks. The scan was performed in supine, right-sided and left-sided positions, respectively. Each area was given a score between 0 and 3 according to the specific pattern.

RESULTS

In this study, 21 still images and 21 videoclips that enabled dynamic and real-time evaluation were provided. Pleural line assessment, physiologic A-lines, pathologic B-lines, light beam pattern, white lung pattern, and specific patterns for quick recognition and evaluation are described.

CONCLUSION

The potential advantages and limitations of LUS and its areas of use for obstetricians are discussed. LUS is a promising supplementary imaging tool during the SARS-CoV-2 pandemic. It is easy to perform and may be feasible in the hands of obstetricians after a brief didactic course. It may be a firstline imaging modality for pregnant women.