Ultrasonography
Dr. LeeAnn Pack
Dipl. ACVR
Normal Anatomy - Liver
 Size of liver
– Assessed subjectively (rads are superior)
 Parenchyma
– Homogenous, uniform
– Interrupted only by portal & hepatic veins
 Portal veins have echogenic walls
 Hepatic veins = black tubes
 Hepatic arteries are not seen
Normal Anatomy - Liver
 Echogenicity
– Dog: Spleen > liver > kidney
– Cat: Spleen = liver > kidney
 Texture
– More coarse texture than spleen
Normal Anatomy
Portal vein
Diaphragm
Normal
Abnormal
Vasculature
 Portal veins
– More echogenic than hepatic veins due
to surrounding fibro-fatty tissue
– Less visible with PSS, fibrosis, &
cirrhosis
 Hepatic veins
– Best seen cranially near diaphragm
(emptying into vena cava)
– Walls not visible
Vasculature
Indications for US - GB







Thickened wall
Stones
Mucoceles
Cholestasis
Cholecystitis
“Sludge”
Icterus
US Technique - GB
 How to find it?
 Anechoic, round to
oval structure to
right of mid-line
Normal Anatomy - GB
 Wall is thin
echogenic line
 Size of GB is
variable
 Cat GB is bi-lobed
Feline Bi-lobed GB
Enhancement
Pathology - GB
 Kiwi-shaped extensions
– GB mucocele
 Hyperechoic areas in wall
– Edema
– Acute inflammation
 Large, hyperechoic sediment
– Sludge vs Cholelith
 Cholelith – usually cause acoustic shadowing
GB Mucocele
GB Mucocele
GB Mucocele + perf
Cholelith
Sludge in GB
Thickened GB Wall
Normal Anatomy Spleen
Splenic Hilus
Normal
Abnormal
Ultrasound Technique - Spleen
 Left side of body
 Head of spleen
– Under border of rib cage on left
 Body & tail of spleen
– Along left body wall
– Ventral or lateral to left kidney
 Scan sagittal & transverse
Anatomy
 Size of normal spleen variable
– Assessed subjectively
– Enlarged spleen may cross midline or
extend caudally to the bladder
 Parenchyma
– Homogenous, finely textured
 Echogenicity
– Dog: Spleen > liver > kidney
– Cat: Spleen = liver > kidney
Normal Spleen
Anatomy
 Capsule
– Smooth, regular, VERY echogenic
 Splenic veins
– Only other structure normally visualized
– Poorly visualized except near hilus
 “Whale tail”
– Enlargement subjective
 Hilus
– Check for lymphadenopathy
Splenic Hilus
Non Homogenous
Splenic Mass
Neoplasia
 Lymphosarcoma
– Diffuse or focal/multifocal
– Hypoechoic or hyperechoic
– Can appear normal
 Hematoma, hemangioma,
hemangiosarcoma
– Unable to differentiate
– Focal
– Hypoechoic, hyperechoic or mixed
Lymphosarcoma
Hemangiosarcoma
Thrombosis
Splenic Thrombus
Myelolipoma
U/S Technique - Bladder
 Use high-resolution transducers (7-12
MHz)
 Located very superficially
 Pressing too hard distorts the image
Normal Anatomy - Bladder
 Bladder wall thickness (1-2mm)
– Dog: 1.6 mm
– Cat: 1.7 mm
 Wall thickness changes with bladder
size
 Ureters & urethra not visible unless
filled with urine
Pathology
 Intraluminal changes
– Urinary calculi
– Gas bubbles
– Cellular and crystalline debris
– Blood clots
 Bladder wall changes
– Cystitis
– Neoplasia
– Polyps
Urinary Calculi
 Calculi very hyperechoic
 Large calculi can cause acoustic
shadowing
 Ballotment doesn’t usually make calculi
move, but standing the animal will
Urinary Calculi
Calculi
Cystic Calculi
Cystic Calculi
Debris
 Variable echogenicity
 Can become thick enough to form
confluent layer with bladder wall
 Vigorous ballotment will cause a
swirling pattern – looks like snow globe
Cystitis
 Chronic cystitis leads to diffuse thickening
of wall
 Small mucosal masses sometimes present
 Muscular hypertrophy caused by chronic
partial lower urinary tract obstruction
 Emphysematous cystitis
Cystitis
Chronic Cystitis
Neoplasia
 Single or multiple masses
 Irregularly shaped, broad-based hypo or
hyperechoic masses protruding into
bladder lumen
 Transitional cell carcinoma most
common
Neoplasia
Neoplasia
Indications for U/S - Kidneys
 U/S very useful for evaluating:
– Size, shape, position, echogenicity
 In some cases, has replaced EU’s
– Provides more info regarding morphology
 Does NOT provide information about
renal function
U/S Technique - Kidneys
 The left kidney is found just medial to the
head of the spleen
– Usually close to the body wall so start at body wall
and pull transducer medial
 The right kidney resides in the renal fossa of
the liver
– Start at liver and proceed caudal along body wall
– Can be more difficult to find and more difficult to
make a “pretty image”
– May be under the rib cage
Normal Anatomy - Kidney
 Location
– Left kidney: caudal to stomach & caudomedial to spleen
– Right kidney: within caudate process of
caudate lobe of liver
 Length (in sagittal plane):
– Dog: depends on size & weight of the dog
– Cat: 2.8-4.2 cm
 Echogenicity
– Cortex hyperechoic to the medullary portion
Normal Anatomy - Kidney
 The cortex and medulla should be of equal
thickness and clearly defined
 Capsule is slightly hyperechoic
 Best to see renal pelvis on the transverse
view
Normal Anatomy - Kidney
Note the Capsule
Lymphosarcoma
Renal Infarct
Polycystic Kidneys
Polycystic Kidneys
Lymphosarcoma
Interstitial Nephritis
Ethylene Glycol
Large Renal Cyst
Nephrolith
Normal Sagittal
Hydronephrosis
Hydronephrosis
Hydronephrosis
Hydroureter
Normal Transverse
Hydronephrosis