Fluoroscopy has made endourology possible, but its two dimensionality and poor tissue contrast limit its applications. Recent advances in computer technology are making it possible for surgeons to interact with three-dimensional CT and MR images. Initial interactive navigation systems tracked the position of surgical instruments on previously acquired images using optical, ultrasonic, or electromagnetic devices. More recently, real-time imaging and instrument tracking have become possible, such as with the open interventional MR scanners. The problems created by patient motion and tissue deformation during manipulation may thereby be overcome.
