Abdominal Ultrasonography in the Horse. Equipment. Indications. Leanne Begg BVSc DipVetClinStud MS MACVSc DipACVIM RANDWICK EQUINE CENTRE

Transcription

1 Abdominal Ultrasonography in the Horse Leanne Begg BVSc DipVetClinStud MS MACVSc DipACVIM RANDWICK EQUINE CENTRE Equipment 2.5 mhz phased array Colic Abnormal biochemistry Urea/creatinine kidneys AST/GGT/alk phos/bilirubin liver Abnormal haematology Leucocytosis Elevated fibrinogen looking for abscess spleen, liver or anywhere! 1

2 Abdominal ultrasonography Stomach Small intestine/colon Liver Spleen Kidneys Bladder Stomach Left side, 10 th to 13 th intercostal space, ventral to ventral lung margin, medial to spleen Hypoechoic wall and an echogenic luminal surface as is normally gas filled Evaluate stomach wall neoplasia My preference is endoscopy with 3m endoscope, as can visualise whole wall when empty and biopsy if required. 2

3 Small intestine Duodenum right side, 10 to 12 th 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 mm2 Anterior enteritis Distended small intestine Can be seen anywhere Colics,, assess caudal abdomen under flank (don t t get kicked!) and if distended will see Assess peristaltic activity/ileus ileus 3

4 Distended small intestine Colic but prefer rectal exam good in minis and foals Anterior enteritis colic, fever, refluxing Weight loss/ple/malabsorption see low albumin, if severe low globulin, glucose absorption test useful Colon Right dorsal colon thickness in Right Dorsal Colitis Normal thickness is mm Normal appearance is high amplitude gas echo with smooth curvilinear appearance Haustral markings evident 4

5 Right Dorsal Colitis (PBZ toxicity) low albumin, colic, useful diagnostic test vs GA/Laparotomy and biopsy Assess motility/ileus ileus Impactions Intussusceptions = donut or bulls eye Displacements nephrospenic entrapment see colon lateral to spleen and cannot visualise left kidney Liver Right side, 6 th to 15 th intercostal spaces Ventral to lung margin Left side, 7 th to 9 th 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 Elevated AST, GGT, alkaline phosphatase, bilirubin (conjugated) = biliary obstruction, bile acids Chronically (liver failure), see low albumin, low urea (converts ammonia to urea) 5

6 Site for liver biopsy right 12 th to 14 th I/C space, lines from tuber coxae to elbow and shoulder Do clotting profile first - PT, PTT (platelet count, fibrinogen, FDP, ATIII) Spleen Left side along ventral lung border Extends to lateral aspect of left kidney (forms window for scanning kidney) Ventrally can go to ventral abdominal midline Can be seen lateral or medial to liver More echogenic than liver Rarely primary site of disease in the horse, but secondarily affected Neoplasia Abscesses Haematoma Site for biopsy/aspirate 6

7 Haemoabdomen peritoneal fluid PCV =/< peripheral PCV Colic dorsal displacement of left colon Liver/spleen LHS? Kidneys Right kidney between last 2 ribs on the right (15 th to 17 th I/C space at level of tuber coxae); equilateral triangle shape Left kidney behind last rib in paralumbar fossa bean shape window created by spleen Normally 10 14cm medially to laterally 7

8 Kidneys 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 Elevated urea/creatinine Haematuria ARF vs CRF Identify nephroliths Differentiate diffuse from focal disease Identify ideal area to biopsy Approach Transcutaneous vs rectal Gas in bowel may block image Transrectal better for visualising ureters 8

9 Right kidney Left kidney Bladder Rectal approach best in adult 5 mhz probe Urine anechoic to varying degrees of echogenicity normally Sedimentation can be normal 9

10 Examine bladder wall Identify uroliths Endoscopy of bladder also useful to identify source of blood in haematuria 10