Ch.41-Kidneys and Ureters Flashcards
What are your radiographic findings and ddx?
Discussion question…
Breed over represented in forming polycystic kidneys?
Inherited polycystic kidney disease is seen in
long-haired cats (autosomal dominant), sometimes associated
with hepatic and pancreatic cysts
***In dogs, cairn terriers (recessive
mode of inheritance) and can be identified at a young age.***
CT image findings?
Transverse computed tomography (CT) image of the 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.
Dosage for contrast for CT:
IV contrast 400 to 800 mg I/kg body weight
What’s yor dx?
Abscess in crania pole of kidney
the cranial pole of the kidney is enlarged and contains a poorly delineated hypoechoic cavity. A focus of hyperintensity w/ reverberation artifact is seen (consistent w/ gas)
What is Pre-ureteral vena cava (or circumcaval ureter)?
a common vascular anomaly in cats (prevalence of 22.4%) where the ureter courses dorsal to the caudal vena cava and displaces the vena cava ventrally. This anomaly has been associated with ureteral strictures in people and may predispose cats
for urinary tract signs.
Indications of renal evaluation via US:
Any signs of renal dysfunciton
**Ultrasound is the method of choice to evaluate renal architecture
and vascularity**
Dx based on this US image?
ureterolith
When do you take rads after contrast administration in excretrory urography?
VD and right lateral radiographs are acquired
immediately after injection and are repeated typically after 5,
20, and 40 minutes or until a diagnosis is reached.
Differential diagnoses for ureteral dilatation include:
obstruction (e.g., calculi, clots, strictures, masses), ectopic ureter, inflammation (e.g., ureteritis, pyelonephritis), atony, and ureteral tears.
Explain what happens wafter giving the contrast in an excretory urography?
- renal areteries become opacified approx. 5-7 seconds post injection
- excretory urogram can be divided in 2 phases:
- nephrogram phase: uniform opacification of the renal parenchyma. begins after ~10 secs post inj and lasts up to 2 min until pyelogram phase starts
- pyelogram phase: contrast is concentrated in the renal tubules
Ddx:
hypercalcemia
FIP
acute tubular necorsis
lepto
pyogranulomatous vasculitis
Perirenal or subcapsular fluid may be the
result of:
acute renal failure, urine leakage, ureteral obstruction,
hemorrhage, abscessation, perirenal pseudocysts, and neoplasia.
Abdominal or pelvic canal trauma may affect the kidneys
and/or ureters. What image modality allows most complete evaluation of these damages?
CT provides the most complete evaluation of suspected renal trauma.CT allows simultaneous assessment of trauma to soft tissue and bones, as well as blood supply of injured
organs
What’s your dx?
Ventrodorsal (VD) oblique radiograph from an excretory
urogram of a dog with bilateral ectopic ureter.
What are your findings?
Dilation of right renal pelvis and ureter
the renal pelvis is distended
but not filled with contrast medium; instead there is a large filling defect. This filling defect extends into a
dilated, tortuous proximal ureter, obstructing it (B, arrow).
Advantages of antegrade US Pyelography? And what is the indication to do this procedure? What are some contraindications?
This procedure can be performed in azotemic patients without
loss of image quality. In addition, each renal pelvis and ureter
can be assessed individually.
The main indication for this procedure is suspected
ureteral obstruction. Renal pelvis diameter should e at least 5mm
Patients w/ coagulopathies
What’s your ultrasonographic findings and most likely dx?
Renal lymphoma tends to occur bilaterally and causes
enlarged, irregularly shaped kidneys with a hyperechoic cortex.
Focal or multifocal nodules and masses have also been
reported.
What’s your ultrasonographic findings and most likely dx?
Ethylene glycol toxicity leads to the most dramatic increase
in cortical and medullary echogenicity with a hypoechoic
rim at the corticomedullary junction and hypoechoic central
medullary regions
Other tumors that
may affect the kidneys are:
histiocytic sarcoma, plasma cell
tumor, metastatic carcinoma, hemangiosarcoma, and lympho-
sarcoma.
How do kidneys look in CT?
soft tissue attenuating, except for a small
amount of fat surrounding the renal pelvis.
What are your US findings:
Pelvis dilation due to pyelonephritis. The renal
medulla is hyperechoic, resulting in poor corticomedullary definition. The
retroperitoneal fat surrounding the kidney is very hyperechoic and inflamed.
Acute pyelonephritis can lead to mild renal enlargement,
whereas renal size is reduced in chronic pyelonephritis.
Peninephric speudocyst has been associated with what disease?
Pseudocyst formation is caused by a transudate and has been
associated with underlying renal parenchymal disease, such as
interstitial nephritis. The affected kidneys are often reduced
in size and have signs of chronic renal disease
US signs of acute renal injury
Ultrasonographic findings associated
with acute kidney injury leading to acute tubular nephrosis
or necrosis, interstitial nephritis or glomerulonephritis include
renal enlargement, subcapsular or perirenal effusion, and
cortical hyperechogenicity.
What is the normal diameter of ureters:
Normal ureters are not more than 2 to 3 mm in width.
What are some ddx?
hydronephrosis, perirenal cyst, primary renal carcinoma
Ureteral tumors are rare. Reported types include:
leiomyoma,
leiomyosarcoma, and transitional cell carcinoma. Extension of
a transitional cell carcinoma of the urinary bladder neck into
the distal ureter is common. Fibroepithelial polyps in the
proximal aspect of the ureter have been described in dogs.
Indications for extrectory urography:
suspected or hx of trauma
hematuria
suspected ectopic ureters
locating a kidney in the prescence of a retroperitoneal mass
What dog breed is associated with renal cystadenocarcinoma and have concurrent dermatofibrosis?
Nodular
dermatofibrosis in German shepherd dogs is associated with
renal cystadenocarcinoma.
Primary renal tumors:
renal adenocarcinoma, squamous cell carcinoma,
papillary carcinoma, and nephroblastoma
Ddx acute renal failure
toxins (e.g., ethylene glycol, lily
in cats, and grapes in dogs)
bacterial, protozoal, and rickettsial
infections (e.g., leptospirosis, babesiosis, Lyme disease, pyelone-
phritis)
drugs, hypercalcemia, sepsis, ischemia,
multiple organ
dysfunction syndrome,
pancreatitis, and hyperviscosity.
Advantage of CT over radiographs for a contrast study?
CT has the advantage that the entire
urinary tract can be imaged without superimposition of any
other structure.
At what level the right and left kidneys are usually seen on rads?
Left: L1-L3 (dogs)
Right: 13th rib (dogs)
In cats: between L1-L4
US signs for chronic renal disease
decreased corticomedullary definition
cortical cysts (have been observed w/ chronic degenerative renal changes)
mineralized foci in cortex
small kidneys
irregular margination
can see cortical infartcs
Can you use MRI and Nuclear Scintigraphy to evaluate the kidneys?
Yes
What’s your radiographic findings, ddx and most likely dx?
Soft tissue opacity mass effects where the kidneys are supposed to be.
ddx: polycystic kidneys, lymphoma, leukemia, congenital ectopic ureters, bilateral hydroneprosis, acute renal failure
did an ultrasound and saw this… what is your dx?
polycystic kidneys
How do normal kidneys look like in US?
Smoothly thin hyperechoic capsule
renal cortex in most patients is hypoechoic to isoechoic to liver and spleen
medulla is hypoechoic
well defined corticomedullary definition
renal pelvis diamters < or = to 2mm
normal cat kidney size 3-4.3mm
normal dog size 10mm/10lb added wihtin the normal range of 3-10cm
Renal pelvis dilation greater
than ____ has a high specificity for ureteral obstruction.
13 mm
Describe how does the renal pelvis look like in a contrast study:
The
normal renal pelvis is curvilinear and less than 2 mm in width.
Where should you look for the ureters in th urinary bladder?
presence of two urine jets from the
dorsolateral bladder wall.
Mean renal pelvis diameter of dogs and cats w/ pyelonephritis is approx:
3.6 mm in dogs and 4.0 mm in cats.
More important, the shape of the renal pelvis is usually distorted with infection, resulting
in blunted and asymmetric pelvic diverticula, seen both on excretory urography and ultrasound
What are ueteroceles?
are cystic dilations of the submucosal portion
of the distal ureter and are often associated with an ectopic
ureter.
Usually wihtin the bladder lumen
contraindications for excretory urography include:
anuric renal failure
dehydration
hypotension
known hypersensitivity to iodinated media
Renal hyperparathyroidism leads to:
generalized osteopenia evidenced by thinning of the bone cortex with a double cortical line.The skull is usually affected first. Bone resorption of the maxilla and mandible with fibrous replacement results
in thickening with reduced radiopacity.
What’s your US findings and most likely dx?
Severe hydronephrosis due to ureteral obstruciton
Normal renal length in cats on rads:
normal renal length has been measured
to be 2.4 to 3.0 times the length of L2.
Intact cats tend to have larger kidneys (2.1-3.2 times length of L2) vs neutered cats (1.9-2.6 times length of L2)
What’s your radiographic finding?
Ureteral dilation
Normal renal length in dogs on rads:
Renal
length in normal dogs ranges between 2.5 and 3.5 times the
length of L2
What is the dose for contrast in excretory urography?
Iodinated contrast medium is administered intravenously
as a bolus injection at a dose of 600 to 700 mg iodine (per
kg body weight.
Describe how does the renal divertical looks in a contrast study
The pelvic diverticula may be seen in some dogs and most cats and appear as thin (1 mm) spikes radiating from the pelvis
toward the periphery.
**Neither the renal pelvis nor diverticula
should have blunted, rounded edges.**
