South African Equine Veterinary Association Congress 2015 Protea Hotel Stellenbosch
tissue and this must be differentiated from a renal calculus (no acoustic shadow with the former).
The ureters are unlikely to be visible unless distended but can be imaged transrectally from the
bladder.
In acute renal failure, the kidneys commonly appear normal; in some cases reduced echogenicity
and swollen capsule may be seen, with a very distinct cortico-medullary junction. Chronic renal
failure causes increased echogenicity and the kidneys will be smaller and irregular in outline,
possible with nephroliths.
Peritoneal cavity
Peritoneal fluid is not always imaged in normal horses. Small volumes may be seen between
abdominal organs and should be hypoechoic and homogenous. Increased volume can be a nonspecific finding in many gastrointestinal disease processes, including inflammatory bowel disease,
peritonitis and neoplasia. Large amounts of fluid acts as a good acoustic window and often loops
of intestine can be seen floating freely in the fluid. Increased echogenicity is indicative of
increased cellularity, and haemorrhage has a characteristic swirling image. Intestinal rupture is
associated with large volumes of fluid and fibrin deposition.
Further reading
Bethell S et al (2010) Repeatability and reproducibility of transabdominal ultrasonographic intestinal wall thickness
measurements in thoroughbred horses. Vet Radiol Ultrasound 51 (6) 647-651.
Epstein K et al (2008) Serial gastrointestinal ultrasonography following exploratory celiotomy in normal adult horses.
Vet Radiol Ultrasound 49 (6) 584-588.
Epstein K et al (2008) Gastrointestinal ultrasonography in normal adult ponies. Vet Radiol Ultrasound 49 (3) 282286.
Freeman S L (2003) Diagnostic ultrasonography of the mature equine abdomen. Equine Vet Educ. 15 (6) 319-330.
Kihurani et al (2009) Transcutaneous ultrasonographic evaluation of the air-filled equine stomach and duodenum
following gastroscopy. Ultrasound 50 (4) 429-435.
LeJeune S & Whitcomb M B (2014) Ultrasound of the equine acute abdomen. Vet Clin Eq 30 353-381.
Pease A P et al (2004) Accuracy of increased large-intestine wall thickness during ultrasonography for diagnosing
large colon torsion in 42 horses. Vet Radiol Ultrasound 45 (3) 220-224.
Whitcomb M B (2012) Ultrasound and the nonacute abdomen: the abdominal organs. Proceed. AAEP 58 28-37.jmc
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