Berlex Inc. is  recalling a single lot (No. 41500A) of its intravenous x-ray contrast agent, Ultravist Injection 370 mgI/mL, 125 mL, (iopromide injection) NDC 50419-246-12, EXP 01/2007, due to the presence of particulate matter in conjunction with crystallization. Berlex is undertaking this recall in consideration of the potential for serious safety problems if the product is administered to patients, including thrombosis of blood vessels, thromboembolism, and injury or infarction of end organs such as heart, kidney, and brain, according to a Berlex release.