Ultrasound

• Ultrasound imaging still uses the idea of sound waves (sonography) for detection.
• The probe sounds energy out and accepts reflective energy. Look at the way that some tissues reflect or absorb the energy. That is how the image is created.
• Ultrasound should be used as a way to guide a diagnosis, not determine.
• Ultrasound can be used with intervention or guiding a diagnosis.
• The ultrasound computer takes the energy and creates an image.
• The image is created in real-time. This is a large difference in ultrasound compared to other imaging methods. This includes seeing movement in real-time.
• The largest limitation of ultrasound is image distortion. This is created by whether or not you are using the right probe and how far away the tissue is that you are attempting to see.
• Curvilinear probes are best for abdominal ultrasound. It is able to expand the waves wider. This however results in more scattering (loss of the sound) as the waves travel farther away. Also, tissues that are farther away from the probe will seem larger than those closer.
• As sound waves make their way through tissues, they can become slightly ‘lost’ due to large amounts of fluid in our tissues.
• Tissues that are less water-filled and have more space, have a lot of echo.
• Tissues that are filled with water have no echo, and the sound is distorted (sound is being absorbed as it goes through the water).
• The top of the ultrasound is skin and subcutaneous tissue. You are looking superficial to deep.
• Cortical bone images are very bright (not fluid-filled).
• Subcortical bone will show up as black. This is because all of the sound hits the cortical bone and immediately bounces back (no waves go through the cortical bone).
• Tendons image bright.
• Muscles image dark due to good blood supply. Muscles will have white stripes, which is typically fascia.
• Hyperechoic tissues reflect more energy. They will produce brighter images.
• Hypoechoic tissues reflect little energy. They will produce dark images.
• Ligaments are bright on ultrasound.
• Bursa is dark on ultrasound.
• Hyaline cartilage is dark on ultrasound when next to light cortical bone.
• Fibrocartilage is bright on ultrasound. it is difficult to distinguish next to bone.