Fig. 5

Gallbladder adenomyomatosis: typical US findings in annular type (a), fundal type (b and d), segmental type (c) and diffuse type (e). Gallbladder wall thickening (line) is always seen in gallbladder adenomyomatosis, but it is non-specific. On b-mode images, Rokitansky–Aschoff sinuses (arrows) typically appear anechoic (a), but they can also appear hyperechoic if cholesterine crystals or calcifications are present (b and c). Comet-tail reverberation artefacts (Figures b and e, arrowheads) or acoustic shadowing (c, arrowheads) are usually observed profoundly in RAS. On colour Doppler images (d), twinkling artefacts (arrowheads) may be observed profoundly in RAS