Lung Ultrasound May Support Diagnosis and Monitoring of COVID-19 Pneumonia

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) is characterized by severe pneumonia and/or acute respiratory distress syndrome in about 20% of infected patients. Computed tomography (CT) is the routine imaging technique for diagnosis and monitoring of COVID-19 pneumonia. Chest CT has high sensitivity for diagnosis of COVID-19, but is not universally available, requires an infected or unstable patient to be moved to the radiology unit with potential exposure of several people, necessitates proper sanification of the CT room after use and is underutilized in children and pregnant women because of concerns over radiation exposure. The increasing frequency of confirmed COVID-19 cases is striking, and new sensitive diagnostic tools are needed to guide clinical practice. Lung ultrasound (LUS) is an emerging non-invasive bedside technique that is used to diagnose interstitial lung syndrome through evaluation and quantitation of the number of B-lines, pleural irregularities and nodules or consolidations. In patients with COVID-19 pneumonia, LUS reveals a typical pattern of diffuse interstitial lung syndrome, characterized by multiple or confluent bilateral B-lines with spared areas, thickening of the pleural line with pleural line irregularity and peripheral consolidations. LUS has been found to be a promising tool for the diagnosis of COVID-19 pneumonia, and LUS findings correlate fairly with those of chest CT scan. Compared with CT, LUS has several other advantages, such as lack of exposure to radiation, bedside repeatability during follow-up, low cost and easier application in low-resource settings. Consequently, LUS may decrease utilization of conventional diagnostic imaging resources (CT scan and chest X-ray). LUS may help in early diagnosis, therapeutic decisions and follow-up monitoring of COVID-19 pneumonia, particularly in the critical care setting and in pregnant women, children and patients in areas with high rates of community transmission.     

Lung Ultrasound vs. Chest X-Ray Study for the Radiographic Diagnosis of COVID-19 Pneumonia in a High-Prevalence Population

BackgroundThe viral illness severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), more commonly known as Coronavirus 2019 (COVID-19), has become a global pandemic, infecting over 100 million individuals worldwide.ObjectivesThe objective of this study was to compare the test characteristics of point-of-care lung ultrasound (LUS) with chest x-ray study (CXR) at radiographically detecting COVID-19 pneumonia.MethodsThis was a single-center, prospective, observational study at an urban university hospital with > 105,000 patient visits annually. Patients ≥ 18 years old, who presented to the Emergency Department with predefined signs and symptoms of COVID-19, were eligible for enrollment. Each patient received an LUS using a portable, handheld ultrasound followed by a single-view, portable anteroposterior CXR. Patients with an abnormal LUS or CXR underwent a non-contrast-enhanced computed tomography scan (NCCT). The primary outcome was the radiographic diagnosis of COVID-19 pneumonia on NCCT.ResultsOne hundred ten patients underwent LUS, CXR, and NCCT; 99 LUS and 73 CXRs were interpreted as positive; 81 NCCTs were interpreted as positive, providing a prevalence of COVID-19 pneumonia of 75% (95% confidence interval [CI] 66–83.2) in our study population. LUS sensitivity was 97.6% (95% CI 91.6–99.7) vs. 69.9% (95% CI 58.8–79.5) for CXR. LUS specificity was 33.3% (95% CI 16.5–54) vs. 44.4% (95% CI 25.5–64.7) for CXR. LUS positive predictive value and negative predictive value were 81.8% (95% CI 72.8–88.9) and 81.8% (95% CI 48.2–97.7), respectively, vs. 79.5% (95% CI 68.4–88), and 32.4% (95% CI 18–49.8), respectively, for CXR.ConclusionLUS was more sensitive than CXR at radiographically identifying COVID-19 pneumonia.     

胸部HRCT评分在新型冠状病毒肺炎诊断中的应用价值

目的探讨新型冠状病毒肺炎（COVID-19）高分辨率CT（HRCT）表现及胸部HRCT评分在COVID-19临床诊疗中的应用价值。 方法收集连云港地区同时行RT-PCR及胸部CT的COVID-19确诊患者28例及非COVID-19患者67例,观察分析病变的分布、范围、形态及密度,纵隔、肺门有无淋巴结,胸腔及胸膜有无异常。根据COVID-19的CT表现,利用胸部HRCT对COVID-19及非COVID-19患者进行评分并分为0~5级,分别评价各等级对COVID-19的诊断价值。 结果28例COVID-19中,胸部HRCT示病变呈双肺胸膜下或多中心分布20例,单发或多发斑片状或节段性磨玻璃密度影11例,磨玻璃伴小叶间隔增厚14例,磨玻璃伴实变8例,实变5例,支气管壁增厚或扩张18例,弥漫性小叶中心磨玻璃样结节分布5例,网格状及蜂窝样纤维索条5例,胸膜增厚1例。COVID-19与非COVID-19患者相比,病变呈双肺胸膜下或多中心分布（71% vs 12%）比例升高,磨玻璃伴小叶间隔增厚（50% vs 13%）比例升高,差异具有统计学意义（P＜0.001）。COVID-19与非COVID-19患者的其他HRCT表现,差异无统计学意义（P＞0.05）。以5级、4级及以上、3级及以上、2级及以上、1级及以上评分标准诊断COVID-19,敏感度、特异度、准确度、阳性预测值、阴性预测值、Kappa值分别为64.3%、97.0%、87.4%、90.0%、86.7%、0.669;92.9%、82.1%、85.3%、68.4%、96.5%、0.679;100.0%、59.7%、71.6%、50.9%、100.0%、0.466;100.0%、29.9%、50.5%、37.3%、100.0%、0.201;100.0%、7.5%、29.5%、31.1%、100.0%、0.045。 结论COVID-19胸部HRCT表现具有一定的特征。胸部HRCT评分可以对COVID-19高度疑似患者的控制及早期治疗提供有效的检查手段,有利于医疗机构控制疫情及提高治愈率。     

Coronavirus Disease 2019 Phenotypes,Lung Ultrasound,Chest Computed Tomography and Clinical Features in Critically Ill Mechanically Ventilated Patients

Chest computed tomography (CT) may provide insights into the pathophysiology of coronavirus disease 2019 (COVID-19), although it is not suitable for a timely bedside dynamic assessment of patients admitted to intensive care unit (ICU); therefore, lung ultrasound (LUS) has been proposed as a complementary diagnostic tool. The aims of this study were to investigate different lungs phenotypes in patients with COVID-19 and to assess the differences in CT and LUS scores between ICU survivors and non-survivors. We also explored the association between CT and LUS, and oxygenation (arterial partial pressure of oxygen [PaO₂]/fraction of inspired oxygen [FiO_2]) and clinical parameters. The study included 39 patients with COVID-19. CT scans revealed types 1, 2 and 3 phenotypes in 62%, 28% and 10% of patients, respectively. Among survivors, pattern 1 was prevalent (p < 0.005). Chest CT and LUS scores differed between survivors and non-survivors both at ICU admission and 10 days after and were associated with ICU mortality. Chest CT score was positively correlated with LUS findings at ICU admission (r = 0.953, p < 0.0001) and was inversely correlated with PaO₂/FiO₂ (r = –0.375, p = 0.019) and C-reactive protein (r = 0.329, p = 0.041). LUS score was inversely correlated with PaO₂/FiO₂ (r = –0.345, p = 0.031). COVID-19 presents distinct phenotypes with differences between survivors and non-survivors. LUS is a valuable monitoring tool in an ICU setting because it may correlate with CT findings and mortality, although it cannot predict oxygenation changes.     

Lung Ultrasound in Patients with Acute Respiratory Failure Reduces Conventional Imaging and Health Care Provider Exposure to COVID-19

Lung ultrasound gained a leading position in the last year as an imaging technique for the assessment and management of patients with acute respiratory failure. In coronavirus disease 2019 (COVID-19), its role may be of further importance because it is performed bedside and may limit chest X-ray and the need for transport to radiology for computed tomography (CT) scan. Since February 21, we progressively turned into a coronavirus-dedicated intensive care unit and applied an ultrasound-based approach to avoid traditional imaging and limit contamination as much as possible. We performed a complete daily examination with lung ultrasound score computation and systematic search of complications (pneumothorax, ventilator-associated pneumonia); on-duty physicians were free to perform CT or chest X-ray when deemed indicated. We compared conventional imaging exams performed in the first 4 wk of the COVID-19 epidemic with those in the same time frame in 2019: there were 84 patients in 2020 and 112 in 2019; 64 and 22 (76.2% vs. 19.6%, p < 0.001) had acute respiratory failure, respectively, of which 55 (85.9%) were COVID-19 in 2020. When COVID-19 patients in 2020 were compared with acute respiratory failure patients in 2019, the median number of chest X-rays was 1.0 (1.0–2.0) versus 3.0 (1.0–4.0) (p = 0.0098); 2 patients 2 (3.6%) versus 7 patients (31.8%) had undergone at least one thoracic CT scan (p = 0.001). A self-imposed ultrasound-based approach reduces the number of chest X-rays and thoracic CT scans in COVID-19 patients compared with patients with standard acute respiratory failure, thus reducing the number of health care providers exposed to possible contamination and sparing personal protective equipment.     

Utility of Point-of-Care Lung Ultrasound for Clinical Classification of COVID-19

In this study, the utility of point-of-care lung ultrasound for clinical classification of coronavirus disease (COVID-19) was prospectively assessed. Twenty-seven adult patients with COVID-19 underwent bedside lung ultrasonography (LUS) examinations three times each within the first 2 wk of admission to the isolation ward. We divided the 81 exams into three groups (moderate, severe and critically ill). Lung scores were calculated as the sum of points. A rank sum test and bivariate correlation analysis were carried out to determine the correlation between LUS on admission and clinical classification of COVID-19. There were dramatic differences in LUS (p < 0.001) among the three groups, and LUS scores (r = 0.754) correlated positively with clinical severity (p < 0.01). In addition, moderate, severe and critically ill patients were more likely to have low (≤9), medium (9–15) and high scores (≥15), respectively. This study provides stratification criteria of LUS scores to assist in quantitatively evaluating COVID-19 patients.     

Ultrasound versus Computed Tomography Assessment of Focal Lung Aeration in Invasively Ventilated ICU Patients

It is unknown whether and to what extent the penetration depth of lung ultrasound (LUS) influences the accuracy of LUS findings. The current study evaluated and compared the LUS aeration score and two frequently used B-line scores with focal lung aeration assessed by chest computed tomography (CT) at different levels of depth in invasively ventilated intensive care unit (ICU) patients. In this prospective observational study, patients with a clinical indication for chest CT underwent a 12-region LUS examination shortly before CT scanning. LUS images were compared with corresponding regions on the chest CT scan at different subpleural depths. For each LUS image, the LUS aeration score was calculated. LUS images with B-lines were scored as the number of separately spaced B-lines (B-line count score) and the percentage of the screen covered by B-lines divided by 10 (B-line percentage score). The fixed-effect correlation coefficient (β) was presented per 100 Hounsfield units. A total of 40 patients were included, and 372 regions were analyzed. The best association between the LUS aeration score and CT was found at a subpleural depth of 5 cm for all LUS patterns (β = 0.30, p < 0.001), 1 cm for A- and B1-patterns (β = 0.10, p < 0.001), 6 cm for B1- and B2-patterns (β = 0.11, p < 0.001) and 4 cm for B2- and C-patterns (β = 0.07, p = 0.001). The B-line percentage score was associated with CT (β = 0.46, p = 0.001), while the B-line count score was not (β = 0.07, p = 0.305). In conclusion, the subpleural penetration depth of ultrasound increased with decreased aeration reflected by the LUS pattern. The LUS aeration score and the B-line percentage score accurately reflect lung aeration in ICU patients, but should be interpreted while accounting for the subpleural penetration depth of ultrasound.     

Diagnostic Imaging in Newborns,Children and Adolescents Infected with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): Is There a Realistic Alternative to Lung High-Resolution Computed Tomography (HRCT) and Chest X-Rays? A Systematic Review of the Literature

Chest computed tomography has been frequently used to evaluate patients with potential coronavirus disease 2019 (COVID-19) infection. However, this may be particularly risky for pediatric patients owing to high doses of ionizing radiation. We sought to evaluate COVID-19 imaging options in pediatric patients based on the published literature. We performed an exhaustive literature review focusing on COVID-19 imaging in pediatric patients. We used the search terms “COVID-19,” “SARS-CoV2,” “coronavirus,” “2019-nCoV,” “Wuhan virus,” “lung ultrasound (LUS),” “sonography,” “lung HRCT,” “children,” “childhood” and “newborn” to query the online databases PubMed, Medical Subject Headings (MeSH), Embase, LitCovid, the World Health Organization COVID-19 database and Medline Bireme. Articles meeting the inclusion criteria were included in the analysis and review. We identified only seven studies using lung ultrasound (LUS) to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in newborns and children. The studies evaluated small numbers of patients, and only 6% had severe or critical illness associated with COVID-19. LUS showed the presence of B-lines in 50% of patients, sub-pleural consolidation in 43.18%, pleural irregularities in 34.09%, coalescent B-lines and white lung in 25%, pleural effusion in 6.82% and thickening of the pleural line in 4.55%. We found 117 studies describing the use of chest X-ray or chest computed tomography in pediatric patients with COVID-19. The proportion of those who were severely or critically ill was similar to that in the LUS study population. Our review indicates that use of LUS should be encouraged in pediatric patients, who are at highest risk of complications from medical ionizing radiation. Increased use of LUS may be of particularly high impact in under-resourced areas, where access to chest computed tomography may be limited.     

Portable Pocket-Sized Ultrasound Scanner for the Evaluation of Lung Involvement in Coronavirus Disease 2019 Patients

Ultrasound imaging of the lung (LUS) and associated tissues has demonstrated clinical utility in coronavirus disease 2019 (COVID-19) patients. The aim of the present study was to evaluate the possibilities of a portable pocket-sized ultrasound scanner in the evaluation of lung involvement in patients with COVID-19 pneumonia. We conducted 437 paired readings in 34 LUS evaluations of hospitalized individuals with COVID-19. The LUS scans were performed on the same day with a standard high-end ultrasound scanner (Venue GO, GE Healthcare, Chicago, IL, USA) and a pocket-sized ultrasound scanner (Butterfly iQ, Butterfly Network Inc., Guilford, CT, USA). Fourteen scans were performed on individuals with severe cases, 11 on individuals with moderate cases and nine on individuals with mild cases. No difference was observed between groups in days since onset of symptoms (23.29 ± 10.07, 22.91 ± 8.91 and 28.56 ± 11.13 d, respectively; p = 0.38). No significant differences were found between LUS scores obtained with the high-end and the portable pocket-sized ultrasound scanner. LUS scores in individuals with mild respiratory impairment were significantly lower than in those with moderate and severe cases. Our study confirms the possibilities of portable pocket-sized ultrasound imaging of the lung in COVID-19 patients. Portable pocket-sized ultrasound scanners are cheap, easy to handle and equivalent to standard scanners for non-invasive assessment of severity and dynamic observation of lung lesions in COVID-19 patients.     

Lung Assessment with Point-of-Care Ultrasound in Respiratory Coronavirus Disease (COVID-19): A Prospective Cohort Study

Lung ultrasound (LUS) has shown promising diagnostic potential in different pulmonary conditions. We evaluated the diagnostic accuracy of LUS for pulmonary COVID-19. In this prospective cohort study at a Swiss tertiary care center, patients hospitalized with suspected COVID-19 were scanned using a 12-zone protocol. Association of a summation score (0–36 points) with the final diagnosis was tested using the area under the receiver operating characteristic curve and sensitivity and specificity at different cutoff points. Of the 49 participants, 11 (22%) were later diagnosed with COVID-19. LUS score showed excellent diagnostic performance, with an odds ratio of 1.30 per point (95% confidence interval [CI], 1.09–1.54, p = 0.003) and an area under the curve of 0.85 (95% CI, 0.71–0.99). At a cutoff of 8/36 points, 10 of 11 participants later diagnosed with COVID-19 were correctly predicted (sensitivity 91%, 95% CI, 59%–100%), and 29 of the 38 who were not diagnosed with COVID-19 were correctly ruled out (specificity 76%, 95% CI, 60%–89%). LUS demonstrated promising discriminatory potential in people hospitalized with suspected COVID-19.     

重症新型冠状病毒肺炎临床和肺部超声影像特点

目的探讨重症新型冠状病毒肺炎（简称"新冠肺炎"）肺部超声影像学特征，为临床诊治提供参考。 方法选择广州市第八人民医院ICU收治的29例重症新冠肺炎患者，其中重型15例，危重型14例，入ICU 24 h内进行肺部超声评分（LUS），同时收集患者性别、年龄、氧合指数（OI）和病程，计算临床肺部感染评分（CPIS）（由体温、OI、胸部X线片或CT、气道分泌物、白细胞计数组成）。 结果29例患者中男性23例（79.3%），年龄（62.59±11.91）岁，LUS（19.28±4.96）分，OI（184.24±66.18）mmHg（1 mmHg=0.133 kPa），CPIS 4（3，4）分，病程（12.48±5.34） d，其中LUS与OI呈显著负相关（r=-0.742，P=0.000），与CPIS呈显著正相关（r=0.504，P=0.005）。危重型患者的LUS及CPIS明显高于重型患者，OI则明显降低，差异均有统计学意义（P<0.05），两组间性别、年龄和病程比较差异无统计学意义（P>0.05）。348个肺部超声检查区域中主要表现为B2征象，危重型与重型患者比较，N征象明显减少（9.5% vs 23.3%），C征象明显增多（17.3% vs 4.4%），病变区域比例明显增加（90.5% vs 76.7%），差异均有统计学意义（P<0.01）；前区、侧区、后区肺部病变区域依次增加（63.8%，87.9%，98.3%），相互比较差异均有统计学意义（P<0.01）；左肺与右肺超声征象分布和病变区域比较差异无统计学意义（P>0.05）。 结论肺部超声能床旁实时评估重症新冠肺炎患者肺部病变性质、范围，为重症患者的诊断和治疗提供重要参考依据。     

Modality alignment contrastive learning for severity assessment of COVID-19 from lung ultrasound and clinical information

The outbreak of COVID-19 around the world has caused great pressure to the health care system, and many efforts have been devoted to artificial intelligence (AI)-based analysis of CT and chest X-ray images to help alleviate the shortage of radiologists and improve the diagnosis efficiency. However, only a few works focus on AI-based lung ultrasound (LUS) analysis in spite of its significant role in COVID-19.In this work, we aim to propose a novel method for severity assessment of COVID-19 patients from LUS and clinical information. Great challenges exist regarding the heterogeneous data, multi-modality information, and highly nonlinear mapping. To overcome these challenges, we first propose a dual-level supervised multiple instance learning module (DSA-MIL) to effectively combine the zone-level representations into patient-level representations. Then a novel modality alignment contrastive learning module (MA-CLR) is presented to combine representations of the two modalities, LUS and clinical information, by matching the two spaces while keeping the discriminative features. To train the nonlinear mapping, a staged representation transfer (SRT) strategy is introduced to maximumly leverage the semantic and discriminative information from the training data.We trained the model with LUS data of 233 patients, and validated it with 80 patients. Our method can effectively combine the two modalities and achieve accuracy of 75.0% for 4-level patient severity assessment, and 87.5% for the binary severe/non-severe identification. Besides, our method also provides interpretation of the severity assessment by grading each of the lung zone (with accuracy of 85.28%) and identifying the pathological patterns of each lung zone. Our method has a great potential in real clinical practice for COVID-19 patients, especially for pregnant women and children, in aspects of progress monitoring, prognosis stratification, and patient management.     

Early identification of novel coronavirus (COVID-19) pneumonia using clinical and radiographic findings

IntroductionThe Japanese Respiratory Society (JRS) scoring system is a useful tool for identifying Mycoplasma pneumoniae pneumonia. Most COVID-19 pneumonia in non-elderly patients (aged <60 years) are classified as atypical pneumonia using the JRS scoring system. We evaluated whether physicians could distinguish between COVID-19 pneumonia and M. pneumoniae pneumonia using chest computed tomography (CT) findings. In addition, we investigated chest CT findings if there is a difference between the variant and non-variant strain.MethodsThis study was conducted at five institutions and assessed a total of 823 patients with COVID-19 pneumonia (335 had lineage B.1.1.7.) and 100 patients with M. pneumoniae pneumonia.ResultsIn COVID-19 pneumonia, at the first CT examination, peripheral, bilateral ground-glass opacity (GGO) with or without consolidation or crazy-paving pattern was observed frequently. GGO frequently had a round morphology (39.2%). No differences were observed in the radiological findings between the non-B.1.1.7 groups and B.1.1.7 groups. The frequency of pleural effusion, lymphadenopathy, bronchial wall thickening and nodules (tree-in-bud and centrilobular) was low. In contrast to COVID-19 pneumonia, bronchial wall thickening (84%) was observed most frequently, followed by nodules (81%) in M. pneumoniae pneumonia. These findings were significantly higher in M. pneumoniae pneumonia than COVID-19 pneumonia.ConclusionsOur results demonstrated that a combination of the JRS scoring system and chest CT findings is useful for the rapid presumptive diagnosis of COVID-19 pneumonia in patients aged <60 years. However, this clinical and radiographic diagnosis is not adapted to elderly people.     

Bilateral spontaneous pneumothorax in SARS-CoV-2 infection: A very rare,life-threatening complication

In the coronavirus disease 2019 (COVID-19) era, the presence of acute respiratory failure is generally associated with acute respiratory distress syndrome; however, it is essential to consider other differential diagnoses that require different, and urgent, therapeutic approaches. Herein we describe a COVID-19 case complicated with bilateral spontaneous pneumothorax. A previously healthy 45-year-old man was admitted to our emergency department with sudden-onset chest pain and progressive shortness of breath 17 days after diagnosis with uncomplicated COVID-19 infection. He was tachypneic and presented severe hypoxemia (75% percutaneous oxygen saturation). Breath sounds were diminished bilaterally on auscultation. A chest X-ray revealed the presence of a large bilateral pneumothorax. A thoracic computed tomography (CT) scan confirmed the large bilateral pneumothorax, with findings consistent with severe COVID-19 infection. Chest tubes were inserted, with immediate clinical improvement. Follow-up chest CT scan revealed resolution of bilateral pneumothorax, reduction of parenchymal consolidation, and formation of large bilateral pneumatoceles. The patient remained under observation and was then discharged home. Bilateral spontaneous pneumothorax is a very rare, potentially life-threatening complication in patients with COVID-19. This case highlights the importance of recognizing this complication early to prevent potentially fatal consequences.