NEW YORK (Reuters Health) – An iPhone with dedicated software for evaluation of coronary CT angiography (CTA) is highly accurate for detecting and excluding significant stenosis, according to a report in the May JACC: Cardiovascular Imaging.

Coronary CTA interpretation has traditionally required expensive, dedicated, stand-alone 3-dimensional imaging workstations – but new software is making it possible to perform the same tasks on mobile handheld devices.

In the first study of its kind, Dr. Troy M. La Bounty from Weill Cornell Medical College-New York Presbyterian Hospital, New York, and colleagues compared the diagnostic accuracy of using an iPhone 3G device versus a dedicated imaging workstation for interpretation of coronary CTA.

The 102 patients in the study underwent not only CTA but angiography as well. All had stable chest pain and no known coronary artery disease. A total of 405 arteries were included in the study.

Two experienced readers (including one with no iPhone experience) interpreted the CTA images on the hand-held device; a third experienced reader provided an opinion when necessary to achieve consensus. One of the first two readers also re-interpreted the images on a dedicated workstation, at least 4 weeks later and in different sequences.

Quantitative coronary angiography showed significant coronary stenosis at the 50% threshold in 26 patients (26%) and 40 arteries (10%). Angiography confirmed significant stenosis in the left main artery in 1% of patients, in the left anterior descending artery in 11%, in the left circumflex artery in 12%, and in the right coronary artery in 16%.

The iPhone was 95% sensitive and 85% specific overall for detecting significant coronary artery stenosis.

Coronary artery calcium score and body-mass index (BMI) did not influence the diagnostic performance of the iPhone, but study interpretability increased significantly with heart rates of 65 beats/min or lower and with intrascan heart rate variability below 10 beats/min.

There was good agreement between interpretations on the mobile handheld device and on the dedicated 3D imaging workstation, with no significant differences in sensitivity, specificity, or positive or negative predictive value between the techniques.

“The current handheld device represents an early step in the use of remote imaging technology in medical diagnosis,” the investigators conclude.

They add, “Further advances (such as the ability to perform 3D reconstructions) and additional research evaluating these devices may permit their future use in clinical care.”

Reference:

J Am Coll Cardiol Img 2010;3:482-490.