Q: Please can you give a brief introduction to ultrasound devices? How do they work?
A: Ultrasound devices use sound waves to image the organs of the body safely, without the use of radiation. The sound waves are produced by applying a current to a piezoelectric crystal housed in a transducer. The crystal alters shape and creates a sound wave.
When the transducer containing the crystal is applied to the patient the sound enters the body and is then reflected back to the transducer when it encounters an interface. The sound wave that is reflected back to the transducer changes the shape of the crystal and creates an electrical current. The intensity of the returning sound wave determines the intensity displayed on the image.
A gray-scale image is then created depending on the intensity of the returning echoes ranging from black, which represents fluid in the body, mid–greys which may represent organs such as the liver and uterus through to white which represents highly reflective objects such as bone.
Each organ of the body has its own characteristic pattern of echoes – disease processes change the normal echo patterns of organs enabling detection.
Q: What are ultrasound devices used for?
A: Ultrasound imaging has many clinical applications including fetal monitoring, vascular imaging, procedure guidance, and general diagnostic imaging.
Handheld ultrasound systems are intended to be used as an adjunct to the physical exam where more expensive systems are not available such as:
-Diagnosis. Ruling in pathology for clinical examinations of the abdomen, the pelvis, obstetric, cardiac, and the peripheral vascular system.
-Screening. These types of procedures are the so-called “quick-look” examinations to rapidly determine if the patient should proceed to a further, more exhaustive ultrasound examination or perhaps another diagnostic test. A specific example of a screening tests is Abdominal Aortic Aneurysms (“AAA”) screening.
-Guidance. This is one of the fastest growing applications of portable ultrasound systems. Handheld systems are suitable for large vessel vascular/venous access, pleural and abdominal fluid drainage guidance, liver biopsy guidance, and bladder aspiration.
Q: When were handheld ultrasound devices first developed?
A: There is no universally accepted definition of “handheld” ultrasound devices. Some manufacturers have used the term “handheld” with ultrasound products as large as a laptop computer.
Through working extensively with clinicians, it is developed the view that a true “handheld” should be small enough to fit in one’s pocket or to comfortably hang around a clinician’s neck, like a stethoscope, and that the device should weigh no more than one pound (450 grams).
Q: What are the benefits of a handheld ultrasound device?
A: Handheld ultrasound is of greatest benefit when due to size, portability, or cost, larger and more expensive ultrasound systems are unavailable. Because of their more convenient size and substantially lower cost, handheld ultrasound devices are entering a range of clinical settings where previously ultrasound use was impractical.
The fastest growth in the ultrasound market has come from portable systems sold into “emerging markets” like emergency medicine and intensive care, and handheld ultrasound is continuing this trend.
Rural and remote doctors who previously had limited access to ultrasound departments can also assess their patients and rule-in whether they need urgent medical attention requiring travel or air lifting.
Emergency and Intensive Care physicians can assess their patients in the department saving time and improving patient management rather than waiting to transport the patient to and from the ultrasound department.
Obstetric staff are able to quickly and easily determine the presence of a baby’s heart beat and fetal position.
Hand held ultrasound devices allow simple effective ultrasound examinations to be performed at the point of care – speeding up decision making by the clinician.