Without Heinrich we would have no units for the frequency of our probes.
We can thank him for these units as well as for proving Maxwell’s theory of electromagnetism, leading to the invention of radio and television. I suppose we should really be interested in thanking his grandnephew, Carl, who invented medical ultrasonography. Either way, Thanks Hertz family.
One common source of confusion or false positives in the FAST exam is the assessment of the left upper quadrant. We’ve already covered some tips on improving your view of the spleen. This post will illustrate how the stomach can mimic free fluid to the unprepared.
The first image shows a perisplenic (left upper quadrant) view on ultrasound. Note the spleen (S), kidney (K), and diaphragm (D).
As the operator fans anterior and posterior to assess for fluid, anechoic fluid with some dirty shadows and slightly irregular margins is seen (bounded by arrows). This structure is often visualized anterior and medial to the spleen, and represents fluid within the stomach.
The video better illustrates fanning through a sagittal plane and encountering this common artifact.
Scan through the area carefully to ensure this fluid is all accounted for within the confines of the stomach, and does not layer out around the kidney, spleen, or highlight bowel loops at its margins.
Finding the right angle is critical to optimal imaging. In fact ‘right angle’ or perpendicular imaging is the best way to get a clear image. At 90 degrees, many more sound beams reflect back to the transducer than at more shallow angles.
In addition, the ultrasound energy is more spread out when it connects to the tissue at an angle, as seen above.
In this image of the kidney, notice the inferior aspect of the kidney (right arrow) is imaged at nearly 90 degrees. The white lines represent the plane of the kidney.
It has the sharpest border and is well-distinguished from the liver. The middle arrow represents the path of ultrasound energy hitting the the kidney off 90 degrees. Not a bad image but doesn’t look as good as the one imaged at 90 degrees. Finally, the left arrow represents the beam hitting the kidney almost parallel. Note that the kidney-liver interface looks fuzzy and there is a great loss of detail. Most of the ultrasound energy is reflecting off the surface AWAY from the transducer- hardly any is available to reflect back towards the transducer and yield a good image.
Thus, angling the probe 90 degrees to the structure you want to image can increase resolution and improve your image quality.
Sinai’s own Dr. Lana Friedman, Pediatric Emergency Medicine Fellow, was just named one of three recipients of the prestigious SPR Fellow Clinical Research Award. Her abstract entitled, “Accuracy of Point-of-Care Ultrasound (PoCUS) by Novice Pediatric Emergency Sonologists in the Diagnosis of Skull Fractures,” was selected from a very competitive pool of submissions. She will present the abstract at the PAS meeting in Denver in April.
Congratulations to Dr. Friedman and her research advisor, Dr. Jim Tsung!
On November 17, 2011 Dr. Braden Hexom presented research organized by Mount Sinai and conducted at JFK Hospital in Liberia. The project,
Evaluation of Novel Obstetrics Ultrasound Curriculum for Local Healthcare Providers in Liberia
Bentley S, Hexom B, Nelson BP
described a novel ultrasound curriculum developed in concert with providers in Liberia after a needs assessment and analysis of various use models of ultrasound deployment in the area.
It was determined that among the highest-yield applications of point-of-care ultrasound was pregnancy evaluation, especially during the third trimester. According to the United Nations Population Fund, Liberia’s rate of maternal mortality is among the highest in sub-Saharan Africa (994 per 100,000 live births). Increasingly international organizations such as WINFOCUS have lauded ultrasound as a means of empowering patients and providers in under-resourced areas and improving the quality of care delivered.
A great presentation by Alberta Spreafico (Outreach and International Development Program Coordinator at Henry Ford Health Systems) highlights this topic in an eloquent and inspiring fashion. See below for her TED talk!