Volume sweep imaging lung teleultrasound for detection of COVID-19 in Peru: a multicentre pilot study

Abstract

Objectives: Pulmonary disease is a significant cause of morbidity and mortality in adults and children, but most of the world lacks diagnostic imaging for its assessment. Lung ultrasound is a portable, low-cost, and highly accurate imaging modality for assessment of pulmonary pathology including pneumonia, but its deployment is limited secondary to a lack of trained sonographers. In this study, we piloted a low-cost lung teleultrasound system in rural Peru during the COVID-19 pandemic using lung ultrasound volume sweep imaging (VSI) that can be operated by an individual without prior ultrasound training circumventing many obstacles to ultrasound deployment.

Design: Pilot study.

Setting: Study activities took place in five health centres in rural Peru.

Participants: There were 213 participants presenting to rural health clinics.

Interventions: Individuals without prior ultrasound experience in rural Peru underwent brief training on how to use the teleultrasound system and perform lung ultrasound VSI. Subsequently, patients attending clinic were scanned by these previously ultrasound-naïve operators with the teleultrasound system.

Primary and secondary outcome measures: Radiologists examined the ultrasound imaging to assess its diagnostic value and identify any pathology. A random subset of 20% of the scans were analysed for inter-reader reliability.

Results: Lung VSI teleultrasound examinations underwent detailed analysis by two cardiothoracic attending radiologists. Of the examinations, 202 were rated of diagnostic image quality (94.8%, 95% CI 90.9% to 97.4%). There was 91% agreement between radiologists on lung ultrasound interpretation among a 20% sample of all examinations (κ=0.76, 95% CI 0.53 to 0.98). Radiologists were able to identify sequelae of COVID-19 with the predominant finding being B-lines.

Conclusion: Lung VSI teleultrasound performed by individuals without prior training allowed diagnostic imaging of the lungs and identification of sequelae of COVID-19 infection. Deployment of lung VSI teleultrasound holds potential as a low-cost means to improve access to imaging around the world.

Keywords: COVID-19; Chest imaging; RADIOLOGY & IMAGING; RESPIRATORY MEDICINE (see Thoracic Medicine); Telemedicine; Ultrasound.

Figure 1

Lung volume sweep imaging (VSI) teleultrasound system. Illustration of the components of the lung teleultrasound system. In this system, individuals without prior ultrasound experience are guided into entering patient clinical history and performing the lung VSI protocol via an application installed on a tablet. The tablet sends the imaging and clinical history to a cloud accessed by a radiologist to produce a diagnostic report. The diagnostic report is sent back to the tablet to be shared with the health centre. Blue arrows represent input of data, and green arrows represent the flow of the diagnostic report. PACS, picture archiving and communication system.

Figure 2

Lung volume sweep imaging (VSI) protocol. Poster demonstrating each step of the lung VSI protocol performed in this study. Transverse and sagittal orientation scans are acquired in the anterior, lateral, and posterior lung fields. The 12 sweeps compose a full volumetric acquisition of the lungs. A-L represent the order the sweeps were performed in this study with sweep A being the first step and sweep L being the last step.

Figure 3

Screenshots from the teleultrasound system. (A) Screenshot of the protocol select screen on the tablet. (B) Screenshot of the initial screen to enter patient clinical information after selecting the lung protocol. (C) Screenshot of the recording screen while obtaining a volume sweep imaging (VSI) cine clip. (D) Screenshot showing the recording screen once several VSI clips have been obtained.

Figure 4

Example images from lung ultrasound volume sweep imaging (VSI) examinations performed by individuals without prior ultrasound experience. (A) Labelled sagittal orientation still image from a VSI sweep with A-lines signifying aerated normal lung in a 7-year-old asymptomatic patient. (B) Labelled sagittal orientation still image from the same sweep more inferiorly shows the basilar lung. The sweep has been submitted as online supplemental video 2. (C) Labelled transverse orientation still image from a VSI sweep with B-lines in a 77-year-old symptomatic patient with confirmed COVID-19 infection. (D) Labelled sagittal orientation still image from the same patient. The sagittal sweep has been submitted as online supplemental video 3.