DI 4

• High sensitivity, low specificity
• Poor anatomy
• Radiation

• Electrical energy into crystal→ deformation → sound energy
• US

• sound energy reflects off tissues turning into electrical energy → image
• DU

• Reflection of sound energy
• Amount of reflection determine by echogenicity

Ability of tissue to reflect energy

• Bone
• Tendon
• nerve

Cyst

Muscle w/ hyperechoic fat

• 1. low cost
• 2. portable
• 3. can image w hardware
• 4. can do w/ dynamic movement
• 5. can compare sides

• 1. Operator dependent
• 2. Bad of obese pts
• 3. *** cannot cross bone (cant see in SC)
• 4. time consuming

• Fast, cheep, readily available
• Not as good as MR and CT for certain conditions

X-rays penetrate body causing ionization (darkening) of the silver atoms on the film whenever the item is radiotranslucent

• Based on density of object
• Bone: white
• Water/ muscle/ soft tissue: gray (more dense than air)
• Fat: black
• Air :black

Thickness and shape