I have seen many patients reported on ultrasound having gall bladder sludge balls or just sludge ,on sonogram there were hyperechoic foci without shadow,but on surgery they came out to be stones,can anyone give some idea.
From my meagre experience we can say gall stones vary in density , size & formation ( cholesterol, pigment stone etc ). US bean can hardly pass through gall stones, though the pigment stone look more like crystals. In general all stones of more than 1-2 mm size should cast shadow though beam must strike at the centre. & we have to make some positioning of the patient. Some times stones may float over sludge when some confusion might occur. Sludge ball should not cast acoustic shadow & usually not hyperechoic, though a nidus could be forming in the center of the ball giving a hyperechoic appearance, as a precursor stone. Some times echogenic sludge gives broad acoustic shadow posterioly, which could clear off with the underlying process improving. A sludge ball could be associated with concomitant small stones( specially in the neck ) also.
Small non-shadowing stones can be a real challenge. The technical factors of the exam can play an important role in whether or not stones will shadow. First of all, do not use CrossBeam or SonoCT as this may well remove the shadow. Second of all use the highest possible frequency and ensure that the focal point is at or just below the level of the echos. Repositioning the patient to achieve a more shallow scan depth can also help. Sonographers don't always optimize the technical factors on their equipment adequately to demonstrate this important artifact.
I believe there are 3 important factors, one is the percentageof material of which the stones are made (pigments, cholesterol and calcium), secondly the size stones ( because of beam width) and thirdly our machine setting.
the definition of stones vs tumefactive sludge is less clear than we sometimes assume. Sones have a crystalline core (or are mostly crystalline), while sludge represents aggregated bile salts or organic debris. In fact, there is often an element of all of these. So, if there is a (relatively) small crystalline core, with aggregrated pigment and organic matrix, we would likely call it "tumefactive sludge" on US. The surgeon can roll it in his hand, and may therefore call it a stone; while the pathologist may also favor calling it a stone because of the crystal core. I think that often the apparent disparity is do more to definition than sonographic mistake.
"If,there are no acoustic shadow in gallbladder,we consider that is polip"
Polyps are defined by their pathological, not sonographic, appearance. You are welcome to call it a polyp, but it will frequently actually represent adenomyomatosis or pigment stone, and not a polyp. The differences can be academic, since the management, based on symptoms, overlap.