An interruption of the contour of a body structure revealed by radiographic contrast material. It may be due to an obstruction caused by blood clots, emboli, malignancies, or extrinsic compression.
A deviation seen in contrast X-rays can be due to a lesion taking up space within a hollow organ. Generally, during contrast X-rays, a substance that is impermeable to X-rays, known as a contrast medium, is infused into a hollow bodily structure, like the intestine. X-rays are then taken, with the dye highlighting the form of the structure. Any entity that extends into the cavity of a body structure, like polyps in the large intestine or a tumor in the bladder, obstructs that area from filling with the contrast medium, thereby causing a malformed shape to appear on the X-ray.