We often picture out doctors as somebody in white coat with a stethoscope hanging around his neck but this iconic image may change in the future as the 200 year old stethoscope, commonly used by doctors to diagnose patients, may be replaced by hand-held ultrasound devices.

In an editorial published in the journal Global Heart, Jagat Narula and Bret Nelson from Icahn School of Medicine at Mount Sinai, New York, said that the pocket sized ultrasound devices can diagnose problems in the body more accurately than the iconic stethoscope, which has been in use since 1816.

"Many experts have argued that ultrasound has become the stethoscope of the 21st century," the editorial reads. "At the time of writing, several manufacturers offer hand-held ultrasound machines slightly larger than a deck of cards, with technology and screens modelled after modern smartphones."

Ultrasound machines have been around since the 1950's but they weren't as widely used as the stethoscope because of their size. They used to be so big it wasn't easy to carry them along but with the advent of better computer technology, modern ultrasound machines now come in smaller sizes.

The pocket-sized ultrasound devices may be so small they can easily fit in the pocket but they are efficient enough to help doctors diagnose lung, heart and other problems in the body more accurately. Using the device can improve diagnostic accuracy and reduce complications as compared with the stethoscope. "With ultrasound devices, one can not only look at the heart, but all of the organs in the body," Narula said.

What may prevent the ultrasound device from replacing the traditional stethoscope, however, is the price. The hand-held ultrasound device is priced between $8,000 and $10,000, far more expensive than the stethoscope but the authors predicted that the growth of the smartphone-style device will continue. "Certainly the stage is set for disruption; as LPs were replaced by cassettes, then CDs and .mp3s, so too might the stethoscope yield to ultrasound. Medical students will train with portable devices during their preclinical years, and witness living anatomy and physiology previously only available through simulation." the authors said.