basics/intro Flashcards
what is the angle of insonation?
the angle of the beam relative to the tissue or organ of interest, strongest echoes occur when angle of incidence approaches the angle of reflection
what is the definition of anisotropy?
change in the properties of a structure when evaluated in different directions
what is the most common artifact with MSK scanning?
what is the minimum off angle that can cause anisotropy?
anisotropy, can affect tendons, ligaments, nerves and sometimes muscle
little as 5* off
what is reverberation artifact?
when waves pass thru 2 approximated reflective planes, they will be repeatedly reflected between the 2 interfaces
part of the beams return, and part of them bounce back and fourth between the 2
what is side lobe artifact?
can be observed in cystic lesions when the machine misinterprets the signals from the side lobes as waves that have originated from the main beam
seen as hyper reflective objects in the cyst
what can edge artifact be mistaken for?
thickened paratenon
what is range ambiguity artifact?
when the returning 1st pulse echoes arrive after the 2nd pulse echoes have been transmitted
returning 1st pulse echoes will be incorrectly placed near the transducer
causes several parallel lines inside a cyst
what appearance do tendons have?
whisk broom appearance in SAX
what is enesthesis?
where the tendon mineralizes at the insertion point to bone
what is paratenon?
collection of loose connective tissue between the sheath and the tendon, aids in tendon movement
what is a retinaculum?
band of fibrous tissue that holds tendon in position and limits movement, makes a tunnel
what is fibrocartilage?
functions as a shock absorber, found in the meniscus and intervertebral discs
what is articular/hyaline cartilage?
found at the terminal ends of bones in joints, follows contour of the bone surface
minimizes friction and allows weight distribution
what is each muscle fiber covered in?
endomysium
what are groups of fibers covered in?
fascicles
