Download Abdominal Ultrasonography in the Horse Equipment Indications

Abdominal Ultrasonography in
the Horse
Leanne Begg BVSc DipVetClinStud
MS MACVSc DipACVIM
RANDWICK EQUINE CENTRE
Equipment
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2.5 mHz phased array
Indications
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Colic
Abnormal biochemistry
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Urea/creatinine
Urea/creatinine – kidneys
AST/GGT/alk
AST/GGT/alk phos/bilirubin – liver
Abnormal haematology
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Leucocytosis
Elevated fibrinogen – looking for abscess –
spleen, liver or anywhere!
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Abdominal ultrasonography
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Stomach
Small intestine/colon
Liver
Spleen
Kidneys
Bladder
Stomach
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Left side, 10th to 13th intercostal space,
ventral to ventral lung margin, medial to
spleen
Hypoechoic wall and an echogenic luminal
surface as is normally gas filled
Indications
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Evaluate stomach wall – neoplasia
My preference is endoscopy with 3m
endoscope, as can visualise whole wall
when empty and biopsy if required.
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Small intestine
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Duodenum – right side, 10 to 12th rib
space, mid abdomen, medial to the liver
and lateral to RDC, extends to the ventral
aspect of right kidney.
Right lung covers variable amount of right
liver lobe
Normal diameter 22-3.75mm
Anterior enteritis
Distended small intestine
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Can be seen anywhere
Colics,
Colics, assess caudal abdomen under flank
(don’
(don’t get kicked!) and if distended will
see
Assess peristaltic activity/ileus
activity/ileus
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Distended small intestine
Indications
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Colic – but prefer rectal exam – good in
minis and foals
Anterior enteritis – colic, fever, refluxing
Weight loss/PLE/malabsorption
loss/PLE/malabsorption – see low
albumin, if severe low globulin, glucose
absorption test useful
Colon
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Right dorsal colon thickness in Right
Dorsal Colitis
Normal thickness is 2 – 3.75mm
Normal appearance is high amplitude gas
echo with smooth curvilinear appearance
Haustral markings evident
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Indications
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Right Dorsal Colitis (PBZ toxicity) – low albumin,
colic, useful diagnostic test vs GA/Laparotomy
GA/Laparotomy
and biopsy
Assess motility/ileus
motility/ileus
Impactions
Intussusceptions = ‘donut’
donut’ or ‘bulls eye’
eye’
Displacements – nephrospenic entrapment – see
colon lateral to spleen and cannot visualise left
kidney
Liver
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Right side, 6th to 15th intercostal spaces
Ventral to lung margin
Left side, 7th to 9th intercostal spaces
Portal veins – echogenic walls and anechoic
centres of varying size
Hepatic veins – anechoic vascular structures
Hepatic arteries and biliary system usually not
visible
Indications
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Elevated AST, GGT, alkaline phosphatase,
phosphatase,
bilirubin (conjugated) = biliary
obstruction, bile acids
Chronically (liver failure), see low albumin,
low urea (converts ammonia to urea)
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Indications
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Site for liver biopsy – right 12th to 14th I/C
space, lines from tuber coxae to elbow
and shoulder
Do clotting profile first - PT, PTT (platelet
count, fibrinogen, FDP, ATIII)
Spleen
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Left side along ventral lung border
Extends to lateral aspect of left kidney
(forms ‘window’
window’ for scanning kidney)
Ventrally can go to ventral abdominal
midline
Can be seen lateral or medial to liver
More echogenic than liver
Indications
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Rarely primary site of disease in the horse,
but secondarily affected
Neoplasia
Abscesses
Haematoma
Site for biopsy/aspirate
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Indications
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Haemoabdomen – peritoneal fluid PCV
=/< peripheral PCV
Colic – dorsal displacement of left colon
Liver/spleen – LHS?
Kidneys
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Right kidney – between last 2 ribs on the
right (15th to 17th I/C space at level of
tuber coxae);
coxae); ‘equilateral triangle’
triangle’ shape
Left kidney – behind last rib in paralumbar
fossa – ‘bean’
bean’ shape – ‘window’
window’ created by
spleen
Normally 10 – 14cm medially to laterally
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Kidneys
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Normally cortex more hyperechoic than
medulla; corticomedullary junction
distinct (with 5MHz probe;higher
frequency improves resolution)
Renal pelvis is hyperechoic line due to
intrapelvic fat and fibrous tissue
Normal ureter not visible unless dilated
Indications
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Elevated urea/creatinine
urea/creatinine
Haematuria
ARF vs CRF
Identify nephroliths
Differentiate diffuse from focal disease
Identify ideal area to biopsy
Approach
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Transcutaneous vs rectal
Gas in bowel may block image
Transrectal better for visualising ureters
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Right kidney
Left kidney
Bladder
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Rectal approach best in adult
5 mHz probe
Urine anechoic to varying degrees of
echogenicity normally
‘Sedimentation’
Sedimentation’ can be normal
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Indications
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Examine bladder wall
Identify uroliths
Endoscopy of bladder also useful to
identify source of blood in haematuria
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