1.6 Advanced Imaging - DUS

diagnostic ultrasound equipment

pulser, transducer, scan converter, monitor, gel

pulser

delivers electrical energy to ultrasound transducer

transducer

contains array of crystals to generate and receive ultrasound waves, convert the reflected waves to electrical signals (piezoelectric crystals)

linear probe

rays do not spray, flat surface

curvilinear probe

for deeper structures, fanned rays

gel is required on probe to

stabilize and couple the image for viewing, good with convex structures to prevent sliding off

with muscle or tendon imaging

it may be helpful to view during contraction or stretch of the muscle to separate fibers and make pathologies more visible

pt position for ultrasound

relaxed, able to add resistance, imager can view structure at all times

longitudinal sonogram

long axis, scan along the muscle line

transverse sonogram

short axis, scan the thickness of the muscle

tissues with large amounts of reflection

hyperechoic, bright

tissues with small amounts of reflection

hypoechoic, dark

tissues with no reflection

anechoic

echogenicity

color and ocntract

echotexture

internal appearance

ultrasound does not penetrate

bone, cortical bone will be bright, no return from subcortical bone

muscle echogenity

dark image relative to fascia on either side (hypoechoic)

echotexture of muscle

"starry night" - bright spots of fascia and adipose

echogenity of tendon

hyperechoic

echotexture of tendon

parallel fibers in long axis, dense spotted appearance in short axis

echogenity of ligament

hyperechoic

echotexture of ligament

more dense than tendon, randomized fibers

cartilage is primarily made up of

water - will be anechoic

echogenity of nervous tissue

hyperechoic to muscle, hypoechoic to tendons/ligaments, usually run next to anechoic vessels

echotexture of nervous tissue

honeycomb

advantages of ultrasound

cost, availability, value and real time imaging

disadvantages to ultrasound

higher reliance on operator, doesnt penetrate bone, DUS will not cross air interface