Ultrasound Basics

Abstract

Ultrasound is a growing technology in the field of interventional pain management and for the treatment of musculoskeletal injuries. Ultrasound depends upon sound, which is mechanical energy transmitted through a medium by vibration of particles within that medium, forming sound waves, which can be measured. Different tissues have differing speeds of transmission of sound, and it is this change in speed of transmission that allows for two-dimensional reconstruction of the tissue as an image. Using ultrasound, different tissues give different appearances. We refer to the “echogenicity” of respective tissues based upon their appearances using ultrasound. To fully optimize image quality, the ultrasonographer must understand how to manipulate the settings on the ultrasound device including adjusting for depth, gain, time gain compensation, and Doppler ultrasound and selecting the appropriate ultrasound probe. Ultrasound is an excellent choice for soft tissue procedures including intercostal nerve blocks, tenotomies, and aspiration of fluid. Ultrasound-guided procedures can be done in-plane or out-of-plane depending on the comfort or skill level of the practitioner and proximity to sensitive targets. The use of ultrasound may decrease the complication rate of soft tissue procedures. Knowledge of basic anatomy, use of the ultrasound machine, and having a systematic approach are essential for successful ultrasound-guided injections.