Abdominal ultrasound has low accuracy in differentiating gall bladder<unk>  from cancer and is operator dependent. However, it is used as the exam of the first-line due to its wide availability. Ultrasound findings may show thickened gall bladder wall, tiny anechoic spaces (Rokitansky–Aschoff sinuses or RAS), and twinkling artifact (or comet-tail reverberation). Comet tail reverberation, which is due to reflections from cholesterol crystals, is a highly specific sign for<unk> . On CT scan, it may show rosary sign, showing mucosal epithelium with intramural diverticula. Magnetic resonance imaging also plays an important role in the diagnosis of Rokitansky–Aschoff sinuses. In fat-suppression MRI, RAS present with small, rounded, high signal intensity foci, called “pearl necklace sign”.
Adenomyomatosis
Verrucous carcinoma
Mammoplasia
Adenoma
Stromal tumor
Epithelial-myoepithelial carcinoma
Adenosarcoma
Epithelial dysplasia