O RIG INAL RES EA RC H Open Access
Diagnostic use of lung ultrasound compared
to chest radiograph for suspected
pneumonia in a resource-limited setting
, Jordan Rupp
, Frances M. Russell
, Jason Saunders
, Brian Bales
and Darlene R. House
Background: Lung ultrasound is an effective tool for diagnosing pneumonia in developed countries. Diagnostic
accuracy in resource-limited countries where pneumonia is the leading cause of death is unknown. The objective of
this study was to evaluate the sensitivity of bedside lung ultrasound compared to chest X-ray for pneumonia in
adults presenting for emergency care in a low-income country.
Methods: Patients presenting to the emergency department with suspected pneumonia were evaluated with
bedside lung ultrasound, single posterioranterior chest radiograph, and computed tomography (CT). Using CT as
the gold standard, the sensitivity of lung ultrasound was compared to chest X-ray for the diagnosis of pneumonia
using McNemar’s test for paired samples. Diagnostic characteristics for each test were calculated.
Results: Of 62 patients included in the study, 44 (71%) were diagnosed with pneumonia by CT. Lung ultrasound
demonstrated a sensitivity of 91% compared to chest X-ray which had a sensitivity of 73% (p = 0.01). Specificity of
lung ultrasound and chest X-ray were 61 and 50% respectively.
Conclusions: Bedside lung ultrasound demonstrated better sensitivity than chest X-ray for the diagnosis of
pneumonia in Nepal.
Trial registration: ClinicalTrials.gov, registration number NCT02949141. Registered 31 October 2016.
Keywords: Lung ultrasound, Pneumonia, Nepal, Diagnosis, Developing countries
Pneumonia is one of the leading causes of death world-
wide, and in low-income countries, it is the leading cause
of death . These deaths may be prevented by early
detection and targeted antibiotic therapy . However, the
diagnosis of pneumonia is not always clear on presenta-
tion to health care facilities. Imaging usually includes a
chest X-ray or, in some cases, a thoracic computed tomog-
raphy (CT) scan. While the latter has the highest sensitiv-
ity, it is associated with high costs and higher doses of
radiation [3, 4]. Because of these limitations, chest X-ray
continues to be the main diagnostic modality for pneumo-
nia despite its low sensitivity (43–78%) [4–8].
Several studies in high-income countries and one
study by Liu et al. in China, a middle-income country,
have shown ultrasound to be a reliable tool to diagnose
pneumonia with a higher sensitivity and specificity than
chest X-ray [8–13]. Ultrasound is a safe, portable, and
inexpensive diagnostic modality that is widely used in
resource-limited countries . In remote areas with
limited access to X-rays, clinicians are reliant on their
physical examination, which also has limited sensitivity
(47–69%), and therefore, ultrasound for diagnosing
pneumonia has the potential to be very useful in this set-
ting . Even in urban settings, use of bedside ultra-
sound can alleviate diagnostic dilemmas with critically ill
patients, especially where facilities lack portable X-rays.
However, the diagnostic accuracy of ultrasound to diag-
nose pneumonia in low-income countries like Nepal has
not yet been studied. Results from studies in high-
income countries are difficult to extrapolate to settings
* Correspondence: email@example.com
Department of General Practice and Emergency Medicine, Patan Academy
of Health Sciences, PO Box 26500, Kathmandu, Nepal
Department of Emergency Medicine, Indiana University School of Medicine,
Indianapolis, IN, USA
Full list of author information is available at the end of the article
International Journal of
© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.
Amatya et al. International Journal of Emergency Medicine (2018) 11:8