Calculus, originally called infinitesimal calculus or "the calculus of infinitesimals", is the mathematical study of continuous change, in the same way that geometry is the study of shape and algebra is the study of generalizations of arithmetic operations. It has two major branches, differential calculus and integral calculus; the former concerns instantaneous rates of change, and the slopes of curves, while integral calculus concerns accumulation of quantities, and areas under or between curves. [Source: Wikipedia ]

- Bile duct filling defect
- Bladder filling defect
- Bladder outlet obstruction
- Echo within gallbladder
- Echoes within bile ducts
- Fallopian tube calcification
- Hydronephrosis
- Intraluminal ureteral filling defect
- Obstruction of ureter
- Pancreatic duct dilatation
- Pancreatic duct ectasia
- Pancreatic duct obstruction
- Renal collecting system echoes
- Seminal vesicle calcification
- Solid renal mass
- Ureteral and renal pelvic calcification
- Urethral filling defect
- Vas deferens calcification