Lung ultrasound scan non-inferior to chest X-ray for COVID-19 pneumonia diagnosis

11th February 2022

A lung ultrasound scan is an imaging modality found to be non-inferior to chest X-rays for the diagnosis of COVID-19 pneumonia

The use of a lung ultrasound scan has been observed to be non-inferior to the use of chest X-rays for the diagnosis of patients with COVID-19 viral pneumonia. This was the conclusion of a study by a team from U.O.C. Geriatria, Accettazione Geriatrica e Centro di Ricerca per l’invecchiamento, Ancona, Italy.

The use of a lung ultrasound has been advocated for use in symptomatic medical inpatients with known or suspected COVID-19, to support the diagnosis of pneumonitis. Lung ultrasound enables the identification of early lung involvement during the course of an infection with COVID-19.

Nevertheless, the specific role of lung ultrasound in COVID-19 is still evolving and a recent review concluded that the current enthusiasm for lung ultrasound should be directed into strong controlled studies and descriptive analyses towards determining patient outcomes. In addition, ultrasound findings should also be taken in context of all other clinical and radiological.

For the present, retrospective analysis, the authors wanted to demonstrate the usefulness of a lung ultrasound scan in the early diagnosis of COVID-19 positive patients and to compare these results with those of a chest X-ray.

Both the ultrasound and chest X-rays were performed on patients during the visit to an emergency department with symptoms suggestive of COVID-19 and there were no exclusions, such as that all patients who received both a lung ultrasound and chest X-ray were included in the analysis.

The authors used multiple regression analysis in an effort to identify whether any of the observed changes on the lung ultrasound were significant predictors of both the presence of a positive COVID-19 test result and other clinical outcomes such as the need for intubation and subsequent COVID-19-related mortality.

Lung ultrasound scan findings in relation to COVID-19

A total of 479 patients were included in the retrospective analysis, of whom, 82.6% tested positive for COVID-19 (mean age 66.4 years, 41.2% female). The most common findings on the ultrasound were B-lines (80.17%), irregular pleural lines (59.3%) and small sub-pleural consolidations (55.3%). Moreover, a normal chest X-ray was found in only 18.9% of cases.

When looking at the results of the lung ultrasound, there were some significant differences between COVID-19 positive and negative patients. For example, both pleural effusion (P < 0.001) and B-lines (P < 0.001) were significantly different for the two groups of patients.

Using multiple regression analysis, the authors identified how only B-lines and small consolidation were significant predictors of whether a patient tested positive for COVID-19. However, when using adjusted regression models, only consolidations (p < 0.001) on the lung ultrasound scan was significantly associated with a positive COVID-19 test result.

Additional analyses also revealed that predictors of the need for orotracheal intubation were ultrasound findings of small consolidation (p = 0.004) and how the presence of ultrasound effusion was a significant predictor of subsequent COVID-19 mortality (p = 0.045), as was X-ray small consolidation (p = 0.043).

Discussing these findings, the authors suggested that their data showed the value of lung ultrasound for the diagnosis of COVID-19 in patients presenting to an emergency department. They added how lung ultrasound was potentially useful for risk stratification of patients given the association of findings with the need for intubation and the mortality risk.

They concluded that a lung ultrasound scan was shown to be non-inferior to a chest X-ray and that the ultrasound findings were associated with the presence of a positive test result for COVID-19.

Citation
Caroselli C et al. Early Lung Ultrasound Findings in Patients With COVID‐19 Pneumonia. A Retrospective Multicenter Study of 479 Patients J Ultrasound Med 2022

Abnormal chest x-ray increases probability of detecting intrathoracic malignancy

15th October 2021

The presence of an abnormal chest X-ray led to an increased diagnosis of intrathoracic malignancies including non-small cell lung cancer.

An abnormal chest x-ray can help to triage patients who might have lung cancer although the evidence base to support this role is incomplete. However, many studies in the past have failed to adequately define a positive chest x-ray and because of this, a team from the Department of Clinical Radiology, St James Hospital, Leeds, UK, decided to retrospectively examine a cohort of consecutive “self-request” chest x-rays collected as part of the National Awareness and Early Diagnosis Initiative (NAEDI) in the UK. The aim of their study was to establish the accuracy of the chest x-ray in the investigation of malignancy amongst symptomatic adults over the age of 50 years.

For the purposes of the study, the team defined as positive, an abnormal chest x-ray that resulted in the further investigation with computed tomography (CT). Furthermore, because the term thoracic malignancy encompasses a range of tumours, they focused on evaluating the accuracy of the chest x-rays in the detection of non-small cell carcinomas (NSCLC). As part of the NAEDI, patients completed a questionnaire and were able to obtain a chest x-ray without the need for a referral on a walk-in basis to the radiology department, provided that they met the eligibility criteria (based on the questionnaire results) which were symptoms lasting longer than three weeks (cough, haemoptysis, shortness of breath, chest pain, change in voice or loss of weight). At the time of the study, a history of smoking was not a requirement. The main outcomes reported were the sensitivity and specificity for NSCLC and all primary intrathoracic malignancies within a one and two year period. The team determined the sensitivity as the number of cancer diagnoses identified on the basis of a positive CXR divided by the total number of cancers observed. Specificity was defined as the number of negative CXRs divided by the total number of CXRs in those without cancer.

Findings

A total of 8,948 questionnaires were evaluated with 496 (5%) abnormal chest x-rays (i.e., positive) and which resulted in a diagnosis of 133 patients with a primary intrathoracic malignancy in the first year and 168 after 2 years, including 105 and 133 NSCLC in the first and second year respectively.

The sensitivity for NSCLC identified within 1-year was 76.2% (CI 68.0–84.3) and the specificity 95.3% (CI 94.9–95.7). Within 2-years, the corresponding sensitivity was 60.2% (CI 51.8–68.5) and specificity 95.3% (CI 94.8–95.7). Although smoking was excluded from the inclusion criteria, 23% of the cohort were current smokers and 44% ex-smokers. The corresponding 1-year sensitivity for the detection of NSCLC in smokers was 83.3% (95% CI 67.1 – 92.4) and 71.6% (95% CI 57.7 – 82.3) for ex-smokers. The corresponding specificities were 94.2% (current smokers) and 95.4% (ex-smokers).

The authors noted that while a negative chest x-ray does not exclude a diagnosis of malignancy, the baseline risk of lung cancer in the current cohort was 1.9% and that a negative x-ray would reduce this risk to 0.8%. They concluded that a positive chest x-ray is strongly predictive for the presence of malignancy but added that a negative result does not conclusively exclude the diagnosis but allows for an estimation of the risk of malignancy.

Citation

Bhartia BSK et al. A prospective cohort evaluation of the sensitivity and specificity of the chest X-ray for the detection of lung cancer in symptomatic adults. Eur J Radiol 2021