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

Diaphragm

Portal vein

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

Normal

Splenic Hilus

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 & caudo-medial 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