A comparison of the "phrygian cap" deformity with bistable and gray scale ultrasound.

Sixteen patients with a "phrygian cap" deformity of the gall bladder seen with oral cholecystography were further evaluated with both bistable and gray scale ultrasound. The bistable technique produced internal echoes that were suspicious of gall stones. When this same area was reevaluated with the more accurate gray scale technique, the folded-fundus deformity was clearly visualized.