The magnetic resonance imaging (MRI) scan, which takes 30 to 60 minutes, reigns as the current gold standard for hospital heart health measurement. MRI tests are seldom used due to the cost and limited availability. The current second best test is an echocardiograph, obtained via an ultrasound machine. Ultrasound tests take about 45 minutes and require a trained technician. According to a recent study, the echocardiogram may soon yield its silver standard status to a smartphone app.

Engineers at the California Institute of Technology (Caltech) Huntington Medical Research Institute and the University of Southern California (USC) may have obsolesced echocardiography ultrasound testing extremely quickly with the help of a standard smartphone. The researchers reported their results in The Journal of Critical Care Medicine. The success of the work, which moved unexpectedly rapidly from invention to the collection of clinical validation data, is based on measuring the amount the carotid artery moves neck skin when the heart beats. Doctors held iPhone 5 cameras against 72 volunteers’ necks for one to two minutes. Next, the volunteers received MRI exams. The iPhone app’s +/-9.9%  measurement error rate compared favorably to echocardiography’s +/-10.2% error rate. The app measures expansion and contraction of artery walls in the neck to calculate heart blood flow. This measurement, called left ventricle ejection fraction (LVEF) turns out to be a key indicator of what’s happening with someone’s ticker. The app shows the relative blood flow from the heart, aka ejection fraction or EF, a key heart health indicator along with heart rate and other measurements.

With the Caltech/USC smartphone app, patients could test their heart function in less than two minutes without the help — or even presence — of a medical professional. According to the report’s senior author Mory Gharib, “This [test]  has the potential to revolutionize how doctors and patients can screen for and monitor heart disease both in the U.S. and the developing world.”