Vscan VIEW - Fall 2014

Study acquisition Ultrasonographers attempted to acquire standard echocardiography projections of parasternal (long axis and short axis); subcostal; and apical 2-, 3-, and 4-chamber views with PME (Vscan) before doing comprehensive TTE (Philips iE33 xMATRIX) with an echocardiograph system. Ultrasonographers were encouraged to complete the PME examination in 5 minutes or less to simulate the length of time a physician might use the PME device as part of the physical examination. The color flow function of the device was turned off to facilitate rapid acquisition of images in keeping with a first-pass examination.

Study interpretation
Two cardiology fellows with two months or less of basic
echocardiography training and two faculty cardiologists with
advanced training in echocardiography individually interpreted
PME images, which included measurements of the left
ventricular end-diastolic dimensions in the parasternal long-axis
view with electronic calipers built into the software of the PME
device. Color flow and mitral regurgitation were not assessed to
facilitate rapid acquisition of images consistent with a first-pass
screening examination.*

Discussion Accuracy of interpretation of PME images by faculty and fellows is detailed in Table 1 as shown. Physicians with less experience disagreed with each other about what the PME images showed more than physicians with more experience. The findings are promising but suggest the device is not ready for general heart assessment use by clinicians untrained in obtaining and interpreting cardiac images.

Liebo, MD, M., Israel, MD, R., Lillie, PhD, E., Smith, MD, M., Rubenson, MD, D., & Topol, MD, E. (2011). Is Pocket Mobile Echocardiography the Next-Generation Stethoscope? A Cross-sectional Comparison of Rapidly Acquired Images With Standard Transthoracic Echocardiography. Annals of Internal Medicine, 155(1), 33-38.

Eric J. Topol, MD

is a cardiologist at Scripps in La Jolla, California. He leads the flagship NIH supported Scripps Translational Science Institute and is Professor of Genomics at The Scripps Research Institute. He also serves as Chief Academic Officer of Scripps Health and is a co-founder of the West Wireless Health Institute. In 2012, he was voted the most influential physician executive in the United States by Modern Healthcare. He was elected to the Institute of Medicine of the National Academy of Sciences and is one of the top 10 most cited researchers in medicine.

Table 1. Visualizability, Accuracy, and Variability of Readings of Images Obtained by Using Pocket Mobile Echocardiography
TTE
Variable
Abnormal, Visualized, True-Positive Plus True-Negative
Readings (Visualized/Total), %/%*

Variability (l)

Overall Attendings Fellows Overall Attendings Fellows Overall
( 4 Raters)

Attendings ( 2 Raters)

Fellows ( 2 Raters)

Ejection fraction

14(low) 95 93 97 95/91 97/91 93/91 0.71 0.95 0.68

WMA† 13 83 85 81 89/74 90/77 87/71 0.72 0.90 0.47 LVEDD 15(enlarged)95 95 94 92/87 94/90 91/85 0.67 0.82 0.55 Pericardial effusion

(significant)

94 94 94 NA NA NA NA NA NA
Aortic
valve

6 82 86 80 96/79 97/83 95/76 0.76 0.84 0.75

Mitral valve

7 90 90 90 85/77 88/79 82/74 0.35 0.59 0.29

IVCsize‡ 12 75 73 77 78/58 81/59 74/57 0.42 0.84 0.39 IVC inferior vena cava; LVEDD left ventricular end-diastolic dimension; NA not available; T TE transthoracic echocardiography; WMA wall-motionabnormality.

* T TE measurements were not visualized on every scan. The first estimate is the proportion of true-positive and true-negative readings among all scans in which the measurement was visualized (number varies by measurement). The second estimate is the proportion of true-positive and true-negative readings in all patients (n = 97).