ARDMS (American Registry for Diagnostic Medical Sonography) Practice Test

What does the presence of gallstones typically appear as on ultrasound?

1. Hypoechoic masses with increased vascularity

2. Echogenic foci with posterior acoustic shadowing

3. Solid masses with uniform texture

4. Fluid-filled cystic structures

The correct answer is: Echogenic foci with posterior acoustic shadowing

The presence of gallstones on ultrasound is characterized by echogenic foci, which appear as bright spots on the imaging due to their composition. These stones reflect ultrasound waves effectively, creating a strong echogenic signal. Accompanying this echogenicity, there is typically posterior acoustic shadowing, which occurs because the gallstones block the transmission of ultrasound waves to the tissues behind them. This shadowing is a key feature that helps differentiate gallstones from other structures, as it indicates the presence of a strongly reflective object. In contrast to the other descriptions, hypoechoic masses with increased vascularity would suggest different pathological processes, often related to vascular lesions or possibly tumors. Solid masses with uniform texture do not correlate with gallstones, as gallstones typically have a varied and irregular surface. Lastly, fluid-filled cystic structures are indicative of different types of lesions, such as cysts or abscesses, rather than calcified stones like gallstones. Thus, the correct presentation of gallstones on ultrasound is best described by the echogenic foci with associated posterior acoustic shadowing.