Abdominal Ultrasound - Using Practice Based Machines

Equipment and scanning technique
KEY: use highest frequency transducer that penetrates to area under investigation and display smallest depth of field necessary. Curved linear transducers combine desirable characteristics of sector and linear transducers - providing wide near and far fields of view. Start with 7.5 MHz transducer at depth 4–8 cm and then 5.0 MHz. Most rectal and tendon probes are 5–7.5 MHz and work well for visualisation of most abdominal structures.

Liver
Liver parenchyma is homogeneous and of medium echogenicity. Bile ducts are not normally visible, but the portal veins are. Hepatic veins can be traced to the caudal vena cava, although this structure can only be visualised in smaller horses. Estimation of hepatic size in horses is hard and is only relative. In older horses atrophy of the right liver lobe is common making it hard to image any liver in some normal aged animals. Hepatomegaly should be considered if the liver continues beyond the border of the costo- chondral junctions. The ventral margin of the liver should always appear sharp. [...]