Ultrasonographic examination of the abdomen of the goat. II. Liver, spleen, urinary tract and greater omentum

Abstract

This review article describes the ultrasonographic findings of the liver, spleen, urinary tract and greater omentum that were previously obtained in studies of healthy female Saanen goats. Real-time B-mode ultrasonography and a linear or convex 5.0 to 7.5 MHz transducer are used to scan standing goats from both sides. The urinary bladder and urethra are also examined transrectally. The liver is scanned from the intercostal spaces (ICSs) on the right from dorsal to ventral. The parenchymal pattern consists of numerous fine echoes that are homogenously distributed across the entire organ. The dorsal visible margin of the liver runs parallel to the lung in a cranioventral to caudodorsal direction. The visible extent of the liver is largest in the 7th and 8th ICSs and the maximum thickness is measured in the 10th ICS. The caudal vena cava has a triangular shape in cross section and is seen only at the 11th or 12th ICS. The portal vein is oval to circular in cross section with stellate ramifications into the liver parenchyma. The gallbladder is pear-shaped and sometimes extends beyond the ventral margin of the liver depending on the amount of bile. In most goats, the gallbladder is only seen from the 9th or 10th ICS. The spleen is scanned from the left where it is almost always seen from the 11th and 12th ICSs. The parenchymal ultrasonographic pattern is similar to that of the liver. The splenic vessels are embedded in the parenchyma and are seen in longitudinal or cross section. The kidneys are best visualized from the flank and last two ICSs on the right. The ultrasonographic appearance varies with the sectional plane. In a sagittal plane through the hilus, the parenchyma is homogenous with fine, evenly distributed echoes. The medullary pyramids are seen near the sinus as oval to circular hypoechoic structures. The hyperechoic sinus is at the centre of the kidney. The urinary bladder is best visualized transrectally but can also be seen in many goats from either inguinal region. The content of the bladder is usually anechoic and the diameter ranges from 1.0 to 4.8 cm. The urethra is seen transrectally as two adjacent parallel echoic lines without an apparent lumen.

Ultrasonography of kidney and spleen in clinically healthy llamas and alpacas

“…However, in all animals examined the normal non-dilated ureter could not be viewed sonographically. This is also true for cattle, rams and goats [25][26][27][28]. The various structures of the kidneys reported had the same sonographic appearances, whereby the following structures could be imaged: a hyperechoic capsule, a hypoechoic renal cortex, anechoic medullary pyramids and the hyperechoic sinus and hilus.…”

“…In contrast to llamas and alpacas, in most ruminants both kidneys are visible from the right flank when using the percutaneous technique. This is due to the rumen that fills almost the entire left half of the abdomen [25][26][27][28][29][30]. Hence it is surprising that the camelid C1, that is comparable to the rumen of cattle and small ruminants, does not displace the left kidney medially and it could only be imaged in our study from the left abdomen.…”

“…The reported length of the kidneys of goats is between 6.6 and 9.9 cm and the width is between 3.9 and 6.3 cm. In rams, kidney size varies from 7.5 to 9.1 cm in length and 4.1 to 5.4 cm in width [25][26][27]. Comparing these dimensions between camelids and small ruminants, llamas and alpacas appear to have kidneys of similar width.…”

“…The spleen was best viewed in the left paralumbar fossa at the level of the 3rd to 7th transverse processes of the lumbar spine, in both transverse and sagittal views. For anatomic reasons this is different to cattle and small ruminants, where the spleen can be viewed between the 8th and the 12th intercostal spaces [26,31,32]. Knowing the ultrasonographic L-shape of this organ and its location next to the kidney is important for performing and interpreting these sonograms.…”

“…The spleen is surrounded by an echoic capsule that can be clearly differentiated. The splenic parenchyma consists of multiple, small, regularly spaced homogeneous echoes, and the splenic vessels appear anechoic [26,31]. Measurement of the distance between medial and lateral margins of the splenic parenchyma before the splenic bend became visible proved to be a suitable location, since it was reproducible.…”