A kidney stone, medically called a nephrolithiasis or renal calculus, is a hard deposit of minerals and salts that forms within the kidney. On ultrasound, kidney stones appear as strongly echogenic foci within the renal collecting system that produce a clean posterior acoustic shadow, similar to gallstones. While CT scanning without contrast is considered the gold standard for detecting kidney stones, ultrasound is commonly used as the first-line imaging study, particularly in pregnant women, children, and patients being followed for known stones, because it avoids radiation exposure. Ultrasound can also detect the indirect effects of kidney stones, such as hydronephrosis, and can assess for ureteral jets in the bladder to evaluate ureteral obstruction.
Sonography Term