Lung Ultrasound Outperforms Chest X-Rays for Diagnosing Pneumonia in Children

Point-of-care lung ultrasound diagnoses community-acquired pneumonia in children more accurately than chest radiography, according to a systematic review and meta-analysis published in the Egyptian Pediatric Association Gazette. Pooling data from twenty studies covering 2,984 pediatric patients, researchers found that ultrasound achieved a pooled sensitivity of 91 percent (95% CI: 89–93%) and a specificity of 86 percent (95% CI: 83–88%), while chest radiography reached a sensitivity of 88 percent (95% CI: 87–90%) and a specificity of only 76 percent (95% CI: 71–80%).

The analysis, conducted in accordance with PRISMA 2020 guidelines and registered in PROSPERO, searched PubMed, Embase, Scopus, and the Cochrane Library from inception through September 2025. Included studies enrolled pediatric patients aged up to 18 years with suspected community-acquired pneumonia who underwent lung ultrasound, chest radiography, or both, using clinical assessment or computed tomography as reference standards. Summary receiver operating characteristic analysis yielded an area under the curve of 0.9569 for ultrasound versus 0.9291 for chest radiography, indicating stronger overall diagnostic discrimination for the bedside modality.

Community-acquired pneumonia remains one of the leading causes of morbidity and mortality worldwide, with more than three million deaths annually, and children are particularly vulnerable. UNICEF estimates place the incidence of childhood pneumonia at over 1,400 cases per 100,000 children, roughly one case in seventy-one children each year, and the infection is the leading cause of mortality in children under five in low- and middle-income countries. Diagnosis is complicated by non-specific symptoms such as cough, fever, and tachypnoea that overlap with bronchiolitis and viral upper respiratory infections.

Chest radiography has been the conventional imaging standard since X-rays were discovered in 1895, but it carries well-documented drawbacks in pediatric care. Interpretation varies between observers, technical factors including the patient’s hydration status and the phase of illness can produce false-negative or false-positive results, and the ionizing radiation involved raises particular concern in children, who are more radiosensitive than adults and face a longer lifetime risk of radiation-induced malignancies. Lung ultrasound, by contrast, is rapid, non-invasive, and radiation-free, relying on acoustic impedance differences between air-filled and consolidated lung tissue to reveal characteristic artifacts and patterns.

The authors attribute ultrasound’s higher sensitivity largely to its technical ability to visualize the subpleural lung parenchyma using high-frequency transducers in the 7–14 MHz range. Consolidations with tissue-like echotexture, dynamic air bronchograms, B-lines, and pleural line abnormalities are the key sonographic markers of pneumonia, and children’s thinner chest walls provide favorable acoustic windows for detecting them. Several included studies reported that ultrasound identified pulmonary consolidations and pleural effusions missed by initial chest radiography, with some of those findings later confirmed by computed tomography.

The pooled ultrasound estimates came from eight studies, while twelve studies contributed the chest radiography figures. Unadjusted sensitivity for lung ultrasound across the primary studies varied widely, from 78.5 percent to 100 percent, and most of the included research, sixteen of the twenty studies, used prospective designs. The studies were largely single-center investigations with sample sizes ranging from 42 to 949 participants, published between 2012 and 2023.

The review’s authors caution that the pooled figures should be interpreted carefully because of substantial heterogeneity in reference standards. Six studies used chest radiography itself as the reference, an approach that introduces incorporation bias, since chest radiography has a known false-negative rate of roughly 20 percent for pediatric pneumonia, meaning consolidations visible only on ultrasound are misclassified as false positives. Three studies used computed tomography, which is anatomically accurate but not clinically routine for uncomplicated pneumonia, and selective CT use can introduce verification bias. Ten studies relied on composite clinical references integrating symptoms, laboratory markers, imaging, and treatment response, which reflects real-world practice but risks misclassification. Notably, pooled estimates from CT-referenced studies yielded higher ultrasound specificity, 92 percent, than studies using radiography or clinical diagnosis, 84 percent, consistent with the principle that an imperfect reference standard attenuates measured accuracy toward the null.

Quality assessment with the QUADAS-2 tool revealed recurring methodological concerns. Lack of blinding of sonographers to clinical data was a frequent source of bias, since knowledge of high pre-test probability could consciously or unconsciously influence interpretation of subtle findings. Studies conducted in pediatric intensive care units were rated high risk because critically ill children do not represent the broader spectrum of pneumonia severity seen in general emergency departments, and convenience sampling in some studies excluded eligible patients. The absence of microbiological confirmation in almost all included studies also means bacterial and viral pneumonia cannot be reliably distinguished, and sonographic findings of viral and bacterial lower respiratory infections frequently overlap.

The review also addresses practical barriers to implementing ultrasound beyond diagnostic accuracy. Unlike radiology departments, many ultrasound programs lack formal quality assurance mechanisms, with images often not stored or systematically peer-reviewed, which can create medicolegal concerns. Institutional acceptance poses another hurdle: admitting teams such as hospitalists and infectious disease consultants may lack confidence in ultrasound interpretation, leading to repeated imaging that negates the radiation-sparing benefits. The authors argue these barriers can be overcome through image archiving, peer review, multidisciplinary education, and institution-wide protocols.

Ultrasound has recognized technical limits as well: it cannot penetrate air-filled lung, so deep or central consolidations that do not reach the pleural surface may be missed, and its performance depends on operator skill, with optimal training requirements still undefined. The authors conclude that point-of-care ultrasound represents an accurate, non-ionizing imaging option that could serve as a first-line modality, particularly in emergency and resource-limited settings, but recommend it be used alongside clinical assessment, with a low threshold for radiography or computed tomography when clinical suspicion remains high despite negative ultrasound findings. They call for standardized protocols, training curricula, and large pragmatic trials examining whether ultrasound-driven pathways improve patient-centered outcomes such as antibiotic use, length of stay, and healthcare costs.

Subject of Research: Diagnostic accuracy of point-of-care lung ultrasound versus chest radiography for community-acquired pneumonia in children

Article Title: Diagnostic accuracy of point-of-care lung ultrasound compared to chest radiography for identifying community-acquired pneumonia in children: a systematic review and meta-analysis

Article References: Shaban, A., Zaki, H. A., Shaban, E. E., Shaban, A., Elkandow, A., Abdelrahim, M. G., Elmelliti, H., & Abosamak, M. F. (2026). Diagnostic accuracy of point-of-care lung ultrasound compared to chest radiography for identifying community-acquired pneumonia in children: a systematic review and meta-analysis. Egyptian Pediatric Association Gazette, 74(1), Article 117. https://doi.org/10.1186/s43054-026-00617-1

Image Credits: AI Generated

DOI: 10.1186/s43054-026-00617-1

Keywords: lung ultrasound, POCUS, chest radiography, community-acquired pneumonia, pediatrics, diagnostic accuracy, meta-analysis, systematic review, medical imaging, radiation-free imaging, emergency medicine, QUADAS-2