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
In CT, the normal kidney length measures:
- ratio with L2 body
- ratio with aortic diameter
2.7 (2.5-2.9)
7.4 (7.07 - 7.74)
Compared with other renal function testing, renal scintigraphy using technetium-99m diethylenetriamine pentaacetic acid has the advantage of:
being able to determine the relative contribution of each kidney to total renal function.
Is increased renal echogenicity indicative of acute or chronic disease?
observed with both
Which changes occur with AKIs?
enlargement
subcapsular/ perirenal effusion
cortical hyperechogenicity
severe: medullary increase in hyperechogenicity =lack of corticomedullary distinction
appearance of kidneys with ethylene glycol toxicity and why
hyperechoic cortex and medulla due to deposits of calcium oxalate crystals, with hypoechoic rim between them
what tends to cause bilateral irregularly shaped renomegaly?
lymphoma
For which disease is a subcapsular hypoechoic thickening predictive for and what does it represent?
renal lymphoma, subcapsular infiltrate (rather than fluid)
80.9% PPV, 66.7% NPV
what does a corticomedullary rim correspond to? which conditions?
hypercalcemic nephropathy
FIP (pyogranulomatous vasculitis)
leptospirosis
acute tubular necrosis
** also seen in clinically normal dogs and cats***
Which 3 changes will result in renal distortion?
atrophy
infarction
fibrosis
same Cairn terrier aged 4 mo and 16mo
renal dysplasia;
What are the 2 types of renal mineralisation?
nephrolithiasis and dystrophic mineralisation (nephrocalcinosis)
What is more typical location-wise of nephrocalcinosis vs. nephrolithiasis?
nephrocalcinosis tends to be in the diverticula (linear hyperechoic striations)
nephrolithiasis tends to be in the pelvis (curvilinear hyperechoic surface with distal shadow)
PKD : mode of inheritance in (which) cats? what mode of inheritance in (which) dogs?
DLH - autosomal dominant
Cairn terriers - recessive
PKD is associated with which changes in other organs?
hepatic and pancreatic cysts
Where are cysts found in the kidney?
corticomedullary junction
Which renal disease is found in GSD?
Nodular dermatofibrosis in German shepherd dogs is associated with renal cystadenocarcinoma.
RCND (renal cystadenocarcinoma and nodular dermatofibrosis).
https://pubmed.ncbi.nlm.nih.gov/30672048/ - SAYS OTHERWISE
which dogs get renal cystadenocarcinoma and nodular dermatofibrosis?
GSD, onset 5-6 years onwards
a large amount of subcapsular fluid in an older cat is typically:
perinephric pseudocyst
what is the fluid in a perinephric pseudocyst?
- transudate
- exudate
- urine
- haemmorhage
transudate, associated with interstitial nephritis
post-con renal masses are generally
hypoattenuating to normal parenchyma, due to lack of filtration. can be heterogenous if cavitated/necrotic
Renal round cell tumours (e.g. __) are typically (hyperechoic/hypoechoic/cavitated)
histiocytic sarcoma, lymphosarcoma
hypoechoic
how does lymphosarcoma differ frok other renal tumours?
typically bilateral; also in cats has a hypoechoic subcapsular thickening
cavitated renal masses are typically which neoplasia?
hemangiosarcoma
PKD - bilateral renomegaly with undulating margins; hepatic cysts
what is another appearance of lymphosarcoma other than diffuse hypoechogenicity?
Focal or multifocal nodules
The main diameter of the renal pelvis with pyelonephritis, what is 3.6 mm in dogs and 4.0 mm in cats. However, there is a large overlap with normal animals. What is another parameter of the pelvis to look for?
shape - usually distorted with infection, resulting in blended and asymmetric pelvic diverticula.
content - there may be echogenic debris, rather than anechoic urine
Acute renal FAILURE is often associated with (finding).
perirenal effusion
What bone is affected first in renal hyperparathyroidism?
Skull - mandible / maxilla
What boney changes occur with renal hyparathyroidism?
generalised osteopenia > thinning of the subperiosteal cortex which leads to a double cortical line (the periosteum and inner cortex)
- this is replaced by fibrous tissue, so it becomes radiolucent.
- in the mandible/maxilla, the lamina dura disappears, so the teeth appear very opaque in contrast
How might renal hyperparathyroidism affect other structures e.g. blood vessels?
metastatic mineralisation, if Ca:P is increased, which can affect stomach, parenchymal organs, blood vessels
When can parathyroid hyperplasia be detected in renal failure?
when it is chronic
What does this indicate: Poor initial nephrogram that fades quickly
- Insufficient dose of contrast medium
- Primary polyuric renal failure
POOR INITIAL nephrogram followed by progressive increase in
opacification indicates:
- Acute extrarenal obstruction
- Systemic hypotension before contrast-medium
administration - Poor renal blood flow
Poor opacification of the pyelogram phase indicates
- Renal failure—decreased concentrating ability
GOOD INITIAL nephrogram followed by persistent or increasing opacity, indicates:
- Systemic hypotension (may be contrast-medium–induced)
- Contrast-medium–induced renal failure * Acute tubular necrosis
- Acute tubular obstruction
What percentage of which species has pre-ureteral vena cava / circumcaval ureter?
22.4% of cats
What is pre-ureteral vena cava / circumcaval ureter and to what does it predispose cats?
The ureter courses dorsal to the caudal vena cava and displaces the vena cava ventrally. This anomaly may predispose cats for urinary tract signs.
Renal pelvis dilation greater than ___ mm has a high specificity for ureteral obstruction.
13
The resistive index is expected to _________ in an obstructed kidney after administration of a diuretic
increase
dog with congenital polycystic kidney disease, 5 minutes after intravenous injection of iodinated contrast medium. There is opacification of the kidneys during the nephrogram phase with multiple small filling defects corresponding to the cystic lesions.
dog with congenital polycystic kidney disease, 18 hours after IV injection of iodinated contrast medium. The nephrogram persists over a long period of time. Contrast medium has been excreted through the biliary system and had accumulated in the colon. Contrast medium–induced renal failure was suspected.
The sensitivity for detection of ureteroliths when combining radiographs and ultrasound is approximately __%.
90
Are ectopic ureters normal in size or dilated?
Can be normal, but typically dilated and tortuous with associated hydropnephrosis
what are ureterocoeles?
cystic dilations of the distal ureteral submucosa, often associated with ectopic ureters
appearance of ureterocoeles in post-con CT or contrast urography? on US?
CT/rad: round, contrast-filling structure in bladder wall
US: round anechoic cystic structure at the UVJ
TCC in the ureter; which is likelier - primary bladder TCC that has extended into the ureter, or a primary ureteral TCC?
bladder TCC that has extended into ureter
primary ureteral tumors:
leiomyoma/sarcoma
TCC
Which growths have been described in proximal ureters in dogs?
fibroepithelial polyps - unknown etiology, good prognosis when removed
Where do fibroepithelial polyps appear in canine ureters?
proximal aspect
what is a urinoma?
encapsulated urine leakage
dog with a body wall hernia. The left kidney is displaced dorsally into paraspinal soft tissues. The kidney enhances normally, and the renal vessels are intact (white arrows)
urethra and distal ureters in a dog with bilateral ectopic ureters. The two ureters (white arrows) course dorsal to the urethra. They inserted into the urethra just caudal to this image plane.
The focal opacities in the caudal aspect of the retroperitoneal space (black arrow) are due to end-on projection of the deep circumflex arteries and veins. These opacities should not be misinterpreted as ureteral calculi. Visualization of these vessels in lateral radiographs is more common in patients with abundant retroperitoneal fat.
