evaluation of image quality Flashcards
(46 cards)
2 fixed anatomical borders
medial, superior
2 mobile anatomical borders
lateral, inferior
positioning requirements for CC view
posterior tissue, 30-40% muscle, PNL w/in 1cm of MLO, NIP
positioning requirements for MLO view
posterior tissue from axilla to IMF, convex muscle shape down to PNL, out and up lift, NIP
lateral-posterior and superior tissues potentially not well imaged on the ____ view
cc
medial-posterior tissue potentially not well imaged on the ____ view
mlo
3 top reasons for failure on the CC view
PNL not within 1 cm of MLO view- short PNL = poor visualization of the posterior tissue
excessive exaggeration
skin folds or artifacts
failure on the MLO view
poor visualization of posterior tissue,
improper demonstration of the pectoralis muscle,
inadequate amount of pectoralis muscle,
drooping tissue,
skin folds,
breast positioned too high on IR,
inadequate IMF,
inadequate anterior breast compression
poor separation of glandular tissue, unequal exposure of tissue, allows for motion
inadequate compression
breast looks uniform in thickness, reduces dose, reduces unsharpness
optimal compression
motion seen on 2D images- 3 fixes:
increase KVP= decrease in exposure time
hold breath
patient sit down
compression min/max suggestions
pounds
newtons
decanewtons
15-27 LBS
70-120 N
7-12 DaN
which portion should be checked for tautness
anterior
the most common problem in mammography between under/over exposure- according to 1999 ACR manual
underexposure
results in decreased radiographic contrast and when its only present in the densest part of the breast it will obscure lesions and micro-calcifications; image looks “washed out”
underexposure
in mammo you want ___ contrast and ____ dose; ____ contrast allows us to see subtle differences
high
low
high
7 common causes for poor contrast
underexposure
image run under wrong label
inadequate compression
failure to use grid
excessive kvp
improper positioning
implant/hardware
inadequate compression =
beam hardening
ability of the mammo system to capture fine detail in an images
sharpness
1 cause of image unsharpness
patient motion
5 causes of image unsharpness
patient motion
inadequate compression
increase to focal spot size
increase OID
decrease to SID
decreases the ability of the radiologist to recognize tiny structures like calcifications and low contrast structures
noise
another name for noise
radiographic mottle
anything we can see on a mammo image that does not reflect actual breast tissue
artifacts
