Answer

c. Liver ultrasound

Ultrasonography is currently the first imaging option in the workup of a patient with cholestasis. If biliary dilatation is present, cholestasis is 'extrahepatic'. If biliary dilatation is not present, cholestasis is 'intrahepatic'. Although in a patient with clinical characteristics suggestive of PBC (middle-aged woman, associated thyroid disease), AMA is the initial test, an ultrasound should always be performed to rule out extrahepatic obstruction. Hepatitis B is very rarely the cause of cholestasis. Hemochromatosis does not lead to cholestasis.