Imaging of the Urological System Flashcards
scintigraphy?
giving a radioactive isotope to patient and using radiography to locate e.g. overactive thyroid in cats
imaging modalities?
radiography
ultrasound
cytoscopy
MRI
scintigraphy
computed tomography
computed tomography?
slices of the patient
metal in radiography?
prevents photons passing through as it absorbs them- so remains white as the photons haven’t passed through to the film
gas in radiography?
doesn’t absorb the photons so they pass through to the film so the film turns black
contrast studies?
increasing the contrast between the subject of interest and surrounding tissue making them more obvious to the eye
positive contrast in contrast radiography?
contrast agents contain elements that absorb a large proportion of x-rays, so appear white on radiographs
iodine can be used
negative contrast for contrast radiography?
low density substances which don’t absorb many x-rays, so appear darker on radiographs
can use air, carbon dioxide or nitrous oxide
double contrast in contrast radiography?
double contrast often used where both agents are used together
collimation?
can increase or decrease the amount of photons released from x-ray head
lateral abdominal radiograph - so where is the beam centred on?
on mid abdomen
collimation to ensure we include: dorsal skin edge, diaphragm, ventral skin edge and pelvic outlet
how do we position a ventrodorsal abdominal radiograph?
centred on midline caudal to last rib
collimation to include:
entire diaphragm
pelvic outlet
lateral skin edges
where do kidneys lie?
lie retroperitoneally in the dorsal abdomen surrounded by fat
more fat = more contrast = better visibility
where do the ureters lie?
lie in the retroperitoneal space proximally and enter the peritoneal cavity more distally before terminating in the trigone of the bladder
ureters on radiographs?
they are not visible on plain radiographs unless surrounded by significant fat
where are kidneys best assessed from in radiographic anatomy?
best assessed from ventrodorsal radiograph
left and right should be similar in size
size can be objectively assessed in relation to craniocaudal length of L2 on VD view
shape of cats kidneys?
more rounded in shape
need to do what to legs in order to see urethra properyl?
pull back legs forward so that they don’t overlap
pneumocystogram?
removed urine and injected air into bladder
what does the ultrasound use to work?
it uses transmission of sound waves through tissue to produce an image
how is an ultrasound wave produced?
a current is applied to the piezo-elements in the transducer producing an ultrasound wave
echogenicity?
the shade of grey
hyperechoic?
birght grey
hypoechoic?
dark grey
