Transcript Kidney and Bladder US - News, Events, and Publications

Kidney and Bladder US
Mike Ackerley
Kidney
Advantage over other modalities?
 What do you see normally?
 What can we diagnose?
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Advantages
Ease with which the extent of the disease can be
determined within the kidney for focal disease
 Ease of assessment of renal pelvic or ureteral
dilation when fluid distended
 The location and relevance of renal
mineralization can also be assessed
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– When radiographically ID focal renal pelvic or ureteral
mineral opacities and the question of whether
hydronephrosis is present
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Biopsy or fine-needle aspiration can be
expedited by ultrasonographic guidance,
improving the margin of safety as well.
Normals
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Length in saggital plane
– Dog: variable with size of dog
– Cat: 2.8 – 4.2 cm
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Cortex
– In dogs more bright than the liver, but less bright than spleen
– In cats variable, may be equal brightness to that of liver and
approach that of the spleen
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Medullary Papillae
– The renal medulla in dogs and cats is less echogenic than the
cortex.
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Arcuate vessels
Pelvic recess
Renal vessels
Renal pelvis
– If high resolution (7.5 – 10 MHz) transducer is used
Capsule
Pelvis
Cortex
Medulla
Pathology
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Distension
– Diuresis: bilaterally symmetrical and usually mild
– Hydronephrosis: pelvic dilation may become very gross, with
only a think rim of surrounding parenchymal tissue (idiopathic,
or secondary to ureteric obstruction)
– Renal calculus: strongly reflective surface with distal acoustic
shadowing also present.
– Chronic pyelonephritis: the pelvis may dilate while the diverticula
remain small
– Renal neoplasia: secondary dilation of the renal pelvis and
proximal ureter, or mechanical obstruction of the pelvis
– Ectopic ureter: due to stenosis of the ureter ending and/or
ascending infection
– Renal pelvic blood clot: following renal biopsy, coagulopathy,
bleeding neoplasm, idiopathic renal hemorrhage, or trauma
Hydronephrosis
Hydronephrosis
Pathology
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Focal parenchymal abnormalities
– Well circumscribed, anechoic parenchymal
lesion
– Hypoechoic parenchymal lesion
– Hyperechoic parechymal lesion
– Heterogeneous/complex parenchymal lesion
– Medullary rim sign
– Acoustic shadowing
Pathology
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Well circumscribed, anechoic parenchymal
lesion
– Thin smooth wall: single or multiple cysts
– Thick/irregular wall:
 Cyst
 Hematoma
 Abscess
 neoplasia
Pathology
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Hypoechoic parenchymal lesion
– Neoplasia
 Lymphosarcoma
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Hyperechoic parenchymal lesion
– Neoplasia
 1º: chondrosarcoma, hemangioma
 Metastatic: hemangiosarcoma, thyroid
adenocarcinoma
Pathology
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Heterogeneous/ Complex parenchymal
lesion
– Neoplasia
– Abscess
– Hematoma
– Granuloma
– Acute infarct
– Polycystic disease
Polycystic Kidneys
Renal Infarct
Pathology
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Medullary rim sign
– Normal in cats
– Nephrocalcinosis
– Ethylene glycol toxicity
– Chronic interstitial nephritis
– Cats - FIP
Pathology
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Acoustic Shadowing
– Deep to pelvic fat
– Renal calculus
Nephrolith
Pathology
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Diffuse parenchymal abnormalities
– Increased cortical echogenicity
– Decreased corticomedullary definition
Pathology
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Increased cortical echogenicity
– Normal cats
– Inflammatory disease
 Glomerulonephritis
 Interstitial nephritis
 FIP
– Acute tubular necrosis/nephrosis (toxins)
– Renal dysplasia
– Nephrocalcinosis
– Neoplasia
 Diffuse lymphosarcoma
Pathology
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Decreased corticomedullary definition
– End-stage kidneys
– Multiple small cysts
What can we diagnose?
Infarcts
 Cysts/Abscess/Hematoma
 Renal calculus
 Big neoplasia
 Pelvic Dilation
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Bladder
Advantage over other modalities?
 What do you see normally?
 What can we diagnose?

Advantages
Able to evaluate bladder wall thickness
 Able to visualize non-radiopaque
stones/cyrstals (C U)
 Cystocentesis
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Normals
Best when bladder moderately full Ovoid in
shape, with slight elongation caudally at trigone
 Don’t normally see ureters
 Three layers (∆ with size)
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– Mucosa: Hyperechoic
– Muscular: Hypo– Serosal: Hyper-
Normal wall thickness (cat): 1.7 mm ± 0.56
 Normal wall thickness (dog): 1.6 mm
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Pathology
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Calculi
– acoustic shadows are observed deep to calculi
that exceed the diameter of the beam.
– echogenicity and acoustic shadow generation
are independent of chemical composition
(doesn’t matter struvite VS cystine)
– Ballottement doesn’t move calculi, but let
animal stand and calculi will fall.
 Helps differentiate from mineralized bladder wall
and colonic shadowing
Cystic Calculi
Pathology
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Gas bubbles
– Will float to the top, to differentiate from
calculi
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Blood clots
– non-shadowing
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Crystalline sediment
– Vigorous ballottement
– Swirling pattern when standing
Blood Clot
Pathology
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Mural changes
– Cystitis
– Neoplasia
Pathology
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Cystitis
– Chronic cystitis results in diffuse thickening of
the bladder wall
– bladder wall becomes abnormally hypoechoic,
and the normal layering becomes less parallel
– normal sonographic appearance of the
bladder does not rule out the presence of mild
or acute cystitis or idiopathic lower urinary
tract disease in cats
Chronic Cystitis
Pathology
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Neoplasia
– TCC: irregularly shaped, broad-based,
hypoechoic masses protruding into the
bladder lumen
– echo pattern depends on if if fibrosis,
mineralization, and necrosis have developed
– An abrupt transition often observed between
neoplastic mass & adjacent bladder wall
Neoplasia
Pathology
Sonographic appearance of polypoid cystitis,
adherent blood clots, and mural hematomas is
similar to that of neoplasia
 Observation of ureter dilation adjacent to the
bladder wall mass & focal medial iliac
lymphadenopathy tends to support the diagnosis
of neoplasia
 Need aspirate, but must weigh that benefit
against the possibility of seeding the needle
tract with tumor cells
 Traumatic catheterization is useful to retrieve
cells from the mass
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What can we diagnose?
Crystalline sediment
 Calculi
 Blood clots?
 Gas
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