Feline abdominal ultrasonography: what's normal? what's abnormal? The liver.

PRACTICAL RELEVANCE: Abdominal ultrasound plays a vital role in the diagnostic work-up of many cats presenting to general and specialist practitioners. Ultrasound examination of the liver can be key in the diagnosis of diseases such as hepatic lipidosis and hepatic neoplasia. CLINICAL CHALLENGES: Despite ultrasonography being a commonly used modality, many practitioners are not comfortable performing an ultrasound examination or interpreting the resulting images. Even differentiating between normal variation and pathological changes can be challenging for all but the most experienced. When assessing the liver via ultrasound, a diffuse alteration in liver echogenicity may be difficult to detect unless the change is marked and, although comparisons can be made with the spleen and kidneys, this relies on these organs being normal. EQUIPMENT: Ultrasound facilities are readily available to most practitioners, although use of ultrasonography as a diagnostic tool is highly dependent on operator experience. AIM: This review, the first in an occasional series on feline abdominal ultrasonography, discusses ultrasonographic examination of the normal and diseased liver, with focus on the liver parenchyma. It is aimed at general practitioners who wish to improve their knowledge of and confidence in feline abdominal ultrasound and is accompanied by high-resolution images. Ultrasound-guided sampling of the liver is also covered. Future articles will discuss the biliary tree and hepatic vascular anomalies. EVIDENCE BASE: Information provided in this article is drawn from the published literature and the author's own clinical experience.