Almost everything we do at Metropolitan Acoustics is within the audible frequency range – roughly 20 Hz to 20 kHz. Sound above this range is called ultrasound, and you’re likely familiar with its role in medical imaging. However, ultrasound has many additional applications in medicine that continue to evolve. Read on to learn how both conventional and cutting-edge ultrasonic technologies are used in healthcare.
How Does Ultrasonic Imaging Work?
To form an ultrasonic image, a transducer within the ultrasound probe first produces a burst of sound several orders of magnitude above the upper limit of hearing, sometimes up to 20 MHz. The pressure waves race through the targeted area of the body over four times faster than speed of sound in air due to the higher density of human tissue. The same transducer then acts as a microphone to record the returning sound that has been reflected off tissue within the body. The ultrasound machine processes these returning signals, using differences in amplitude and timing to construct an image. Anechoic regions such as fluid are displayed as black whereas highly reflective materials such as bone, foreign objects, or kidney stones appear bright white. The rate of this process can be adjusted based on other factors such as the field of view or resolution of the image, which is dependent on the purpose of the ultrasound, but typically happens 10 to 100 times per second!
Ultrasonic Imaging Procedures
Beyond diagnostics, ultrasound is frequently used in real time to guide medical procedures. Injections, biopsies, and certain surgical interventions benefit from ultrasonic guidance as metal instruments are highly reflective and stand out clearly from the surrounding tissue or fluid. Without the use of ultrasound, many of these procedures would be done tactilely or using laparoscopy. A procedure guided by ultrasound translates to less risk than a purely tactile one and even less invasive than laparoscopic surgeries – meaning faster recovery time.
Therapeutic Ultrasound Devices
There are also several therapeutic uses for ultrasound that are preferred by doctors and patients alike for their ability to be outpatient procedures that require no surgery and may even be performed without anesthesia. Burst Wave Lithotripsy (BWL) and Shock Wave Lithotripsy (SWL) are two such procedures that use targeted pulses of ultrasound to break kidney stones into smaller fragments that are easier to pass. There are also similar devices that are used to break up calcified plaque within arteries. This particular device from Johnson & Johnson is used in conjunction with a balloon angioplasty as arteries with more severe calcification are not as flexible and at risk for serious adverse events, such as a perforation, as the balloon inflates.
While we are not medical professionals at Metropolitan Acoustics, and rarely even consider ultrasound, we can certainly appreciate how sound is being used to improve medical outcomes, reduce invasiveness, and expand what’s possible in modern healthcare. All thanks to some ultra cool sound!