It is frankly difficult to imagine modern medical practice without the use of medical ultrasound imaging as a diagnostic technology – the availability of this critical resource is simply assumed in modern practice. Its evolution has been dramatic in the last decades, moving toward an extremely beneficial ubiquity that was unimaginable within our lifetimes.
Ultrasound has been in use since the mid-20th century, though not in medicine. An early use was to detect internal flaws in steel before they were reshaped into locomotive parts, avoiding many catastrophic failures. The seminal study that opened the doors to modern medical use of ultrasound came in 1958 when the first images were published that showed actual images from human bodies reconstructed from reflected sound waves.
Early technology wasn’t at all ready for everyday use, though. Patients needed to be immersed in a water tank to avoid extraneous artifacts in the then-still crude imaging process. The equipment took up an entire room, and there was no hope of taking it portably to wards and units where the most critical patients were confined.
Advances in the ‘60s and 70’s led to real-time two-dimensional imaging using self-contained equipment on wheeled carts that could be moved by a single technologist to wards, critical-care units, ORs, and even ERs to meet the rapidly growing appetite for the non-invasive, non-ionizing, and pain-free anatomical data that ultrasound could provide. Real-time 2D scanning allowed for analysis of the heart and of a moving fetus, for example, which was never available previously. Technology developed rapidly that allowed for quantitative analysis of blood flow within the body using Doppler interrogation of moving red blood cells, and later allowing for color-coded mapping of blood flow patterns within cardiac chambers and somatic arteries and veins.
Fueled by growing diagnostic demand from clinicians as well as by vigorous competition amongst system manufacturers, new and innovative ways were developed to send sound waves into bodies, and methods were developed to extract greater amounts of information from the returning signals.
Throughout the ‘80s and early ’90s, the performance demands on the ultrasound systems grew exponentially. The carts were crammed with the latest hardware of the age – dozens of circuit boards, hundreds of programmed memory chips, connectors for multiple transducers, and of course a sizeable and heavy CRT display on top of it all. For Radiology systems a camera was in place that used standard X-ray films to capture still images. For cardiology units a professional quality VCR was needed to record real-time data, and a thermal strip chart recorder was installed to capture quantitative M-mode images. System cooling fans were a must, and some of these carts weighed in at close to 400 pounds. Many required a 20 amp plug to satisfy a growing hunger for electrical power. Often labs had to increase their air conditioning capacity by 5,000 BTUs/hour to accommodate the heat output from the systems.
Despite this, systems were portable, making visits to patient floors, and more importantly to Intensive and Coronary Care units, possible. Due to their bulk patient rooms had to be rearranged to place the units at bedside – awkward when there were several IV poles and pieces of wired telemetry in place. Fine-tuning the position of several hundred pounds of equipment on overworked casters often grew frustrating. Imaging evidence was captured and returned to the lab for any necessary processing and analysis, as all images were on tape, strip chart paper, or matrix-formatted films.
In 1996 the first system that followed the model of a standard computer was introduced, loading the OS and all functions from disk, capturing images to digital storage, and communicating them immediately via by then standard Ethernet hospital backbones. No more film cameras were needed, nor strip chart recorders, or VCRs. Still, carts weighed a few hundred pounds, and the use model was unchanged – if you needed an ultrasound you needed to call the right department to get a technologist up or to get a patient delivered to the lab.
The desire for a high-availability solution for obtaining and archiving important ultrasound data routinely or immediately, without phone calls or scheduling, had been a dream for decades. When would imaging be part of routine vitals for certain patients? Clinicians can certainly learn to obtain needed images. Handheld wireless equipment can certainly be more cost-effective than full cart-based systems.
Only when a constellation of technical requirements was realized – ultra miniaturization of microprocessors and computing power, omnipresence of WiFi and Bluetooth technology, dramatic increases in battery technology, and universal availability of portable imaging devices, such as cell phones and tablets – only then could a clinician carry an ultrasound system in the pocket of their lab coat alongside its older sibling, the stethoscope – and this is exactly what Vave has brought to the world today.
Rick Bennett, Echocardiographic Clinical Engineer, Vave Health