Ultrasound - urinary system, kidneys Flashcards
The bladder is usually examined when its in what state
it is distended with urine as an empty or minimally distended urinary bladder may appear to have thickened walls on ultrasonographic examination.
Is between the last 2 mammary chains.
Normal bladder wall thickness in dogs is
1 mm, with thickness increasing mildly as body weight increases.
Wall thickness depends on the degree of filling.
If the bladder isminimally distended(0.5 mL/kg), bladder wall thickness is 2.3 ± 0.43 mm.
If the bladder ismildly distended(2 mL/kg), bladder wall thickness is 1.6 ± 0.29 mm.
If the bladder ismoderately distended(4 mL/kg), bladder wall thickness is 1.4 ± 0.28 mm.
In cats, urinary bladder wall thickness ranges from
1.3 to 1.7 mm.
The urinary bladder should be evaluated in what view with what transducer?
in long axis and short axis, from the apex to the level of the urethra at the ureterovesicular junction.
A 5-, 7.5-, or 10-MHz convex, linear, or vector transducer.
Should be full of urine, not empty. Is between the last 2 mammary chains.
Where should you look when aiming to U/S the urethra?
Place the transducer in a long-axis sagittal position at the level of the urinary bladder.
Move the transducer caudally until the trigone region is identified.
When the transducer cannot move any farther caudally due to the presence of the pubic bone, angle the transducer footprint in a caudal direction.
In females, the urethra should be followed for several centimeters beyond
the urinary bladder to evaluate for (2)
any abnormal urethral thickening or mineralization.
The distal ureters (if seen) can be evaluated as they enter at the ureteral papillae, which are located
along the dorsal urinary bladder wall adjacent to the cranial aspect of the trigone.
Occasionally, echogenic ureteral jets may be seen entering the urinary bladder lumen at the level of the ureteral papillae secondary to ureteral peristalsis.
The histologic layers of the urinary bladder
are difficult to define using U/S in a moderately distended urinary bladder.
If the layers are evident, they will consist of the following: (4)
4 layers: serosa, muscle, submucosa, mucosa
- Outer serosal layer (hyperechoic)
- Three smooth muscle layers (hypoechoic)
- Lamina propria submucosal layer (hyperechoic),
*which parallels the inner mucosal layer (hypoechoic).
Side-lobe artifacts, or pseudosludge, are caused by
mismapped reflections of the secondary U/S beam into anechoic regions, resulting in echogenic areas within the urinary bladder lumen that can be mistaken easily for sedimentation.
Angling the transducer can sometimes decrease the severity of the artifact and, thus, rule out sedimentation in the urinary bladder.
Alternatively, the patient can be imaged in a standing position to assess for gravity dependence, which would be
characteristic of true sludge.
Ureterocele is
a rare congenital ureteral malformation that can be associated with ectopic ureters.
An intravesicular ureterocele is characterized by focal cystic dilation of the distal submucosal portion of the ureter that protrudes into the urinary bladder lumen.
In the fetus, the urachus connects the apex of the urinary bladder with the allantoic sac through the umbilical cord.
Before birth, this structure normally
atrophies. Incomplete closure of the urachus may result in (3)
patent urachus (uncommon in dogs and cats)
urachal diverticulum, or
urachal cyst
What is polypoid cystitis?
Polypoid cystitis is a reversible, exophytic, inflammatory lesion of the bladder mucosa.
basically multiple small masses (polyps) (usually located cranioventrally) that project into the urinary bladder lumen.
What is Emphysematous Cystitis?
Gas-producing micro-organisms (eg, Escherichia coli, Aerobacter, Proteus, Clostridium) accumulate within the urinary bladder wall, lumen, and ligaments.
These micro-organisms ferment glucose, with gas as a by-product. As a result, in patients with glucosuria secondary to diabetes mellitus, gas can be present in
the urinary bladder wall.
Ultrasonographically, the urinary bladder wall is irregularly marginated and hyperechoic, with acoustic shadowing and reverberation produced by the gas.
The position of the gas in the wall
can help differentiate emphysematous cystitis from a normal colon containing gas within its lumen; in emphysematous cystitis the position of the gas does not change with the position of the patient.
TCC
Transitional cell carcinoma (TCC) is the most common neoplasm of the urinary bladder.
It is typically an irregular urinary bladder wall mass with a broad-based attachment projecting into the urinary bladder lumen in the trigone region.
TCCs can be extensive, invading
the ureters, urethra, and/or prostate,
causing lower urinary tract obstruction
and hydronephrosis.
These tumors are typically very vascular and may have areas of dystrophic mineralization.
Urethral TCC is associated with a hypoechoic and thickened wall with a hyperechoic mucosal lining.
Squamous cell carcinoma (SCC) is a
urinary bladder neoplasm of what origin
epithelial origin.
Urinary bladder neoplasms of
mesenchymal origin include botryoid
rhabdomyosarcoma, chemodectoma,
leiomyosarcoma, leiomyoma,
fibroma, fibrosarcoma, hemangioma,
hemangiosarcoma, lymphoma, and mast
cell tumor.
Differentiation of urinary bladder neoplasms is not possible
ultrasonographically; biopsy or traumatic
catheterization is needed for definitive
diagnosis.
How to tell where ureters enter the bladder aka the ureteovesicular junction?
You’ll see raised uretal papillae within the bladder lumen.
The proximal urethra (prostatic urethra in male dogs) can be visualized as…?
The membranous urethra can be visualized …?
The proximal urethra (prostatic urethra in male dogs) can be visualized as a tubular hypoechoic structure continuing caudal to the trigone region of the urinary bladder and extending to the level of the pubic bone.
The membranous urethra cannot be visualized due to its location within the pelvis.
urachal diverticulum with calculus
refraction artefact due to fluid in bladder as well as effusion in peritoneal cavity
cystic calculi
echogenic material in bladder, large blood clot
thickened bladder wall, chronic cystitis
bladder mass in lumen
These are normal Kidneys on U/S.
emphysematous cystitis (bacteria produced gas in the bladder wall)
Measurement of kidney sizes.
Best measured from x-rays compared to L2.
Cats 1.9- 2.6 x L2 length
Dogs 2.75-3.25 x L2 length
Two kidneys should be the same size.
Cat: 3,8-4,4 cm (3,2-4,2 cm)
Dog:
5-9 kg = 3,2 -5,2 cm
10-19 kg= 4.8-6.7 cm
20-29 kg = 5.2-7.8 cm
30-39 kg= 6.1-9.3 cm
40-49 kg= 6.3-9.1 cm
50-59 kg= 7.5-10.1 cm
Echogenicity of the normal kidneys.
A thin echogenic capsule may be visible except at the poles.
The renal cortex is hypoechoic and finely granular in texture.
Usually isoechoic or slightly hypoechoic relative to the liver.
The renal cortex should normally be less echogenic than the spleen.
The medulla is anechoic and divided into segments by the echogenic diverticula and vessels (which may look like hyperechogenic lines).
Ddx for cortical hyperechogenicity.
Ddx for reduced corticomedullary distinction.
perinephric pseudocyst (called pseudo cause they’re not inside the kidney but just outside of it)
fluid-filled fibrous sacs that surround the kidney and are not lined by an epithelium.
In cats, PNPs can be congenital, idiopathic or neoplastic, or occur in association with chronic renal failure.
polycystic kidneys
poor corticomedullary distinction
renal pelvis mildly distended
this is presumptive pyelonephritis in a cat
renal pelvis and proximal ureter distended
dx obstructive hydronephrosis + hydroureter secondary to ureteral calculi
