With recent advancements in miniaturization of technology, how do we know when commercially developed devices are ready for clinical practice implementation? From fitness trackers to wireless medical devices, mobile and digital health technology presents physicians with a plethora of potentially promising and disruptive technologies. We evaluated one such device, Google Glass (Google, Mountain View, CA), a wearable computer with an integrated display screen and a voice-activated camera for transmitting and interpreting transthoracic echocardiographic (TTE) videos.
We selected 14 anonymized TTE studies recorded using an iE33 (Royal Philips, Amsterdam, The Netherlands), with 17 video loops (three studies had two video loops) and a total of 25 key findings (one to five per study). These findings were chosen for their clinical relevance in decision making, such as decreased left ventricular and/or right ventricular systolic function or pericardial effusion. These studies were re-recorded using Google Glass, placed at a distance of 40 to 45 cm from an echocardiography reading room monitor. Three cardiology faculty members (two with level 2 and one with level 3 echocardiography training) and seven cardiology fellows (five second-year fellows and two first-year fellows) were asked to view the Google Glass–obtained recordings on a desktop monitor, an iPad, an iPhone, and Google Glass, as well as the original TTE recordings viewed on a reading room monitor ( Figure 1 ). An interpretation score was calculated by assigning one point to each correct interpretation (maximum score, 25). At least 48 hours were required between each interpretation, and images were shown in random sequence to limit recall. Subjective ratings of image quality and confidence of TTE interpretation were obtained using an aggregate five-point Likert-type scale. The Wilcoxon matched-pairs signed rank test was used to compare interpretation scores for each device. A two-tailed P value < .05 was considered to indicate statistical significance. Analyses were performed using SPSS version 23 (IBM, Armonk, NY).
The interpretation score of the original study viewed on a reading room monitor (24.2 ± 0.9) was superior to the interpretation scores of the Google Glass–obtained recordings viewed on a desktop monitor (21.4 ± 1.4), an iPad (18.3 ± 1.6), an iPhone (18.8 ± 1.3), and Google Glass (17.1 ± 2.0) ( P < .01 for all comparisons). In a poststudy survey of the Google Glass recording quality, seven participants (70%) were somewhat satisfied with the image quality, while three participants (30%) were neutral. With regard to making recommendations on the basis of the recordings, two participants were somewhat comfortable, while the remaining eight were neutral.
The addition of echocardiography to clinical assessment improves diagnostic accuracy and aids in the optimal use of health care resources. Even though the use of echocardiography nearly doubled from 1999 to 2008, it may still be underused in some clinical settings. Point-of-care echocardiography has become increasingly possible with the miniaturization of echocardiographic technology, including pocket ultrasound devices or transducers that can be connected to smart phones or tablets. Pocket-sized echocardiographic devices may provide excellent diagnostic accuracy in the hands of experienced operators. The European Association of Echocardiography mandates specific training for point-of-care echocardiography, while emphasizing that its use should be limited to clinical questions that can be answered using these devices. Therefore, even as the technology has become smaller, more convenient, and cheaper, the technical expertise required for image acquisition and interpretation has not changed (and might actually be increased depending on device design and quality). The American Society of Echocardiography Remote Echocardiography with Web-Based Assessments for Referrals at a Distance study has shown that images obtained by trained sonographers can be uploaded to a cloud computing environment and remotely assessed in <12 hours by physicians worldwide. The Value of Interactive Scanning for Improving the Outcome of New-Learners in Transcontinental Tele-Echocardiography trial used a transcontinental tele-echocardiography educational system to remotely train physicians in image acquisition and image interpretation, with no difference in interpretation accuracy in onsite versus online training participants.
However, convenience should not sacrifice the diagnostic quality of studies used for clinical diagnosis. In our study, interpretation of original TTE studies on high-quality, desktop screens had diagnostic accuracy of 97% (even among physicians with various levels of training in TTE interpretation). As the images were transferred via recordings, diagnostic accuracy decreased to 84% and decreased even further to 68% to 72% when interpretation was performed using smaller screens (smart phone, tablet, head-mounted display). This was likely due at least in part to the relatively low resolution of the video camera we used (720p) and the inability to zoom and autofocus on the device display. Another important limitation of wearable optical displays is the need for real-time, high-speed, transmission of recorded information, secure and compliant with the Health Insurance Portability and Accountability Act, which raises concerns about data privacy and security.
In summary, the use of wearable optical displays is currently limited in its ability to allow remote TTE viewing and interpretation, likely because of limitations in image quality and resolution. Although such devices are not yet “ready for prime time,” with continued technological evolution, they may have a role in clinical practice in the future.