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 Liver assessment is subjective. Edges of the liver lobes should be sharply pointed. Rounded margins of liver lobes and hepatic extension (especially the left lobes) beyond the costal arch suggest enlargement. Abdominal radiography is more reliable for the determination of hepatomegaly.

 Target lesions. Single target lesions have a high predictive value for malignancy. When multiple target lesions are seen, the positive predictive value of malignancy increases from 74% to 81% (Cuccovillo and Lamb 2002), and Global FAST is a rapid and quick assessment test for localized versus disseminated disease by surveying the remainder of the abdomen (AFAST), the thorax (TFAST) including heart (TFAST), and lung (Vet BLUE).

 Normal echogenicity rule of thumb. The spleen (S) is more echogenic (hyperechoic) than the liver (Li) which is the same or slightly more echogenic (brighter) than the cortex of the kidney (CK), remembered as S > Li ≥ CK or by the mnemonic “SLiCK.” For the feline, hepatic echogenicity is often compared to the adjacent falciform fat and the feline liver should be isoechoic to slightly hypoechoic to the falciform fat.

 Gallbladder wall thickness is normally <1 mm in cats and <3 mm in dogs (Hittmair et al. 2001; Spaulding 1993; Quantz et al. 2009).

 Gallbladder luminal content is generally homogeneous anechoic bile although degrees of gallbladder sludge may be considered as clinically irrelevant or may indicate cholestasis based on the patient’s clinical profile (Tsukagoshi et al. 2012).

 Being fluid filled, the gallbladder is subject to several artifacts including side‐lobe, slice thickness, edge shadowing, and acoustic enhancement in the far‐field; and the liver and gallbladder, being adjacent to the strong soft tissue–air interface between the diaphragm and the aerated lung, are subject to mirror image artifact.

 In cats, tortuosity of the bile duct can be a normal variation; however, a bile duct greater than 4 mm (≥5 mm) is considered to be consistent with extrahepatic biliary obstruction.

 When you are unable to effectively visualize the gallbladder using ultrasound (likely due to mineralized material or air), a good rule of thumb is to add radiography.