Interpretation of remotely downloaded pocket-size cardiac ultrasound images on a web-enabled smartphone: validation against workstation evaluation

Background: Pocket-size ultrasound has increased echocardiographic portability, but expert point-of-care interpretation may not be readily available. The aim of this study was to test the hypothesis that remote interpretation on a smartphone with dedicated medical imaging software can be as accurate as on a workstation.

Methods: Eighty-nine patients in a remote Honduran village underwent echocardiography by a nonexpert using a pocket-size ultrasound device. Images were sent for verification of point-of-care diagnosis to two expert echocardiographers in the United States reading on a workstation. Studies were then anonymized, randomly ordered, and reinterpreted on a smartphone with a dedicated, Health Insurance Portability and Accountability Act-compliant application. Point-of-care diagnosis was considered accurate if any abnormal finding was matched and categorized at the same level of severity (mild, moderate, or severe) by either expert interpretation.

Results: The mean age was 54 ± 23 years, and 57% of patients were women. The most common indications for echocardiography were arrhythmia (33%), cardiomyopathy (28%), and syncope (15%). Using the workstation, point-of-care diagnoses were changed in 38% of cases by expert overread (41% left ventricular function correction, 38% valvulopathy correction, 18% poor image quality). Expert interobserver agreement was excellent at 82%, with a Cohen's κ value of 0.82 (95% confidence interval, 0.70-0.94). Intraobserver agreement comparing interpretations on workstations and smartphones was 90%, with a Cohen's κ value of 0.86 (95% confidence interval, 0.76-0.97), signifying excellent intertechnology agreement.

Conclusions: Remote expert echocardiographic interpretation can provide backup support to point-of-care diagnosis by nonexperts when read on a dedicated smartphone-based application. Mobile-to-mobile consultation may improve access in previously inaccessible locations to accurate echocardiographic interpretation by experienced cardiologists.