Ch 41 Kidneys & Ureters Flashcards
Which lateral provides more longitudinal distinction between L and R kidneys?
RIGHT lateral
Which kidney is more mobile and likelier to be displaced ventrally in a fatty retroperitoneum?
LEFT
Both kidneys are relatively round with a smooth surface. Fat opacity is visible at the renal hilus in the lateral view (black arrows); this is a normal finding in many cats.
Normal renal length compared to L2 in dogs?
UP TO 3.5
2.5 - 3.5
Normal renal length compared to L2 in cats?
UP TO 3
2.4 - 3
> > older cats without clinical disease or neutered cats: 1.9 - 2.6
non-neutered: 2.1 - 3.2
What effect does neutered status have on kidney length in cats?
Intact, cats tend to have larger, kidneys, 2.1- 3.2x L2
vs neutered: 1.9 - 2.6x
Which contrast medium for excretory urography has less complications - iodinated or non-ionic? why?
Non-ionic, due to low osmolality
Why does the use of nonionic contrast medium lead to fewer complications?
a) It has a higher osmolarity
b) It has a lower osmolarity
c) It is administered orally
d) It is less effective
b) It has a lower osmolarity
What are contraindications for excretory urography?
a) Hypertension, hyperthyroidism
b) Anuric renal failure, dehydration, hypotension
c) Diabetes, obesity
d) Hyperlipidemia, arthritis
b) Anuric renal failure, dehydration, hypotension…and known hypersensitivity to iodinated contrast media
Dose for IV iodinated contrast medium
600 to 700 mg iodine (I) / kg body weight
Which views and when, for excretory urography
VD and RL
- immediately after injection
- 5, 20, and 40 minutes (or until a diagnosis is reached)
Oblique projections for better visualization of the ureters can be added at 5 minutes and later time points
What are the 2 phases of an excretory urogram?
nephrogram and pyelogram
When should rads be taken after IV contrast for visualisation of renal arteries? which view?
VD, 5-7 seconds
How does a pyelogram phase come about?
Contrast is re-absorbed (with water) into the tubules, and is then excreted into the pelvis /diverticula / ureter
How do you recognise the nephrogram phase?
contrast arrives into the glomerular vessels and is filtered into the nephron
- the renal parenchyma is unniformly opacified
When does the nephrogram phase start and end?
10s - 2 minutes
pre-con
1 min (nephrogram)
5 min (pyelogram)
What percentage of normal dogs still have contrast in the renal parenchyma (nephrogram) 2 hours post-con?
25%
Normal width of ureters
no more than 2-3mm
25%
If renal function is normal, the collecting system is consistently (more/less) opaque than the renal parenchyma.
MORE
Ureter filling (during urogram) may be non-uniform due to
peristalsis
When does the nephrogram phase begin after contrast medium injection?
A) Immediately
B) After 10 seconds
C) After 1 minute
D) After 2 minutes
B) After 10 seconds
what could happen if you administer too much contrast into the renal pelvis too quickly?
overdistension; it could rupture
How is the renal medulla divided from the cortex?
by the hyperechoic interlobar vessels and pelvic diverticula
which is dorsal and which is sagittal?
A - dorsal
B - sagittal
which benefits does an antegrade pyelography have over IV contrast urogram?
- contrast medium is not diluted (with urine)
- presence is not dependent on renal function
What does the duration and degree of kidney opacification during an excretory urogram indicate?
it is (rough) indication of renal function
How do you perform an antegrade pyelogram?
Remove 1-2ml urine from the pelvis
Administer approx. 1/2 this volume of contrast
How does a diuretic help with visualising ureteral jets at the UVJ?
- increases the frequency of urine production (temporarily)
- alters the USG (lowers it) in relation to the urine already in the bladder
Why are some feline renal cortices hyperechoic?
fat deposition
what may be confused with renal mineralisation but is actually normal anatomy?
Arcuate vessels at the corticomedullary junction, they may produce distal acoustic shadowing
What is the hyperechoic anatomy surrounding the renal pelvis called (dense fibrous tissue and fat)?
Sinus
Normal kidney size (cm) in cats
3 to 4.3cm
What is the ratio kidney length to aorta diameter in normal dogs ?
5.5 - 9.1
Which renal vessels can be identified with Doppler?
Renal a. and v.
interarcuate
arcuate
interlobular
Resistive index
What should the renal pulsatility index be less than in dogs / cats?
Dogs: <1.52
Cats: <1.29
Which dose of contrast for CT renal angiography?
reduced dose; 400 mg I / kg bodyweight
When is the optimal time to visualise ureters in CT following IV contrast? how long does opacification persist?
3 minutes
1 hour