Filling defect
Defect in the area that would normally fill with contrast medium in an X-ray or MRI examination. A filling defect in most cases indicates some disease process, and may be caused by different pathological conditions like extensive atheromatous plaques, endothelial dissection, endothelial flaps, thrombus or thromboembolism. Laminar flow during contrast injection may mimic filling defects. A careful evaluation of the probable causes is important whenever a filling defect is seen.
GE Healthcare Glossary