A Feasibility Study of Smartphone-Based Telesonography for Evaluating Cardiac Dynamic Function and Diagnosing Acute Appendicitis with Control of the Image Quality of the Transmitted Videos

Abstract

Our aim was to prove the feasibility of the remote interpretation of real-time transmitted ultrasound videos of dynamic and static organs using a smartphone with control of the image quality given a limited internet connection speed. For this study, 100 cases of echocardiography videos (dynamic organ)-50 with an ejection fraction (EF) of ≥50 s and 50 with EF <50 %-and 100 cases of suspected pediatric appendicitis (static organ)-50 with signs of acute appendicitis and 50 with no findings of appendicitis-were consecutively selected. Twelve reviewers reviewed the original videos using the liquid crystal display (LCD) monitor of an ultrasound machine and using a smartphone, to which the images were transmitted from the ultrasound machine. The resolution of the transmitted echocardiography videos was reduced by approximately 20 % to increase the frame rate of transmission given the limited internet speed. The differences in diagnostic performance between the two devices when evaluating left ventricular (LV) systolic function by measuring the EF and when evaluating the presence of acute appendicitis were investigated using a five-point Likert scale. The average areas under the receiver operating characteristic curves for each reviewer's interpretations using the LCD monitor and smartphone were respectively 0.968 (0.949-0.986) and 0.963 (0.945-0.982) (P = 0.548) for echocardiography and 0.972 (0.954-0.989) and 0.966 (0.947-0.984) (P = 0.175) for abdominal ultrasonography. We confirmed the feasibility of remotely interpreting ultrasound images using smartphones, specifically for evaluating LV function and diagnosing pediatric acute appendicitis; the images were transferred from the ultrasound machine using image quality-controlled telesonography.

Trial registration: ClinicalTrials.gov NCT02271048.

Keywords: Clinical imaging viewing; Smartphone; Telesonography.

Figures

Fig. 1

Remote viewing system using a smartphone: ultrasound videos on the smartphone display transmitted from the ultrasound machine in real time

Fig. 2

Flow diagram of the study design. EC echocardiography, US ultrasonography, LCD liquid crystal display

Fig. 3

Screenshot of original image on LCD monitor of ultrasound machine and the transmitted image on smartphone display: The resolution of a single frame of echocardiography video is reduced by approximately 20 %

Fig. 4

The process of video presentation for the double stimulus impairment scale (DSIS) evaluation; the original videos on the LCD monitor and the transmitted images on the smartphone were sequentially presented to the reviewers for 8 s, separated by 3-s intervals