Unusual causes of sonographic nonvisualization or nonrecognition of the gallbladder: a review.

Nonvisualization of the gallbladder by ultrasound in a fasting patient usually indicates calculous gallbladder disease. However, a number of other less common conditions can prevent gallbladder visualization or recognition. The latter occurs when the location or the morphology of the gallbladder is so altered that the gallbladder is difficult to identify. These conditions can be classified as: (1) congenital anomalies, (2) gallbladder contraction not due to stones, (3) conditions that cause shadowing or reverberation from the near wall of the gallbladder, and (4) the solid gallbladder pattern. Their distinction is important to proper patient management.