The G Scale

• Jason Birnholz, MD

Sep 27, 2018

• Ultrasound, DI Executive

Figure 1 Courtesy of the Boston GlobeFigure

Figure 2 A bistable image of an industrial sponge with cutout holes, 1970. Courtesy of J. Birnholz, MD













Figure 3 10mm pseudo-nodule with 5mm nucleus in a commercial elastography phantom (Sonoscanner U-Lite, 38mm linear array, 10MHz center freq.) Courtesy of Jason Birnholz, MD

http://www.diagnosticimaging.com/ultrasound/g-scale?rememberme=1&elq_mid=3721&elq_cid=894206

Medicine is conservative, because safety comes from sticking with what is established and works. Ultrasound is a powerful diagnostic resource that has provided actionable information throughout its history. The problem is that a lot of policies and practices were solidified when equipment performance was less, general medical sophistication and knowledge were less, and societal needs were different. A lot of the world is playing sonic, sandlot baseball. It’s time to move into digital stadia, where smart ultrasound adjusts the playing field for the application game we are playing.

Comet Tail Artefact CTA and RingDown Artefact RDA

The term comet tail artefact [CTA ] in LUS has caused confusion simply because it is used to describe any vertical artefact, in particular B-lines, which is an ringdown artefact [RDA]. CTA and RDA are generated by distinct mechanisms; while reverberation due to acoustic impedance difference is the mechanism of generating CTA, RDA are caused by resonant vibration due to bubble tetrahedral complexes or their equivalents.

Their appearance in LUS will depend on the state of the lung to provide the right acoustic environment for their generation, in both healthy and diseased patients. Using pneumothorax and interstitial syndrome as examples, we illustrated that the lung comets (CTAs) and B-lines (RDA) have distinct roles in disease diagnosis and the potential pitfalls if they are simply lumped together and called CTAs.