What is injected in angiography to help visualize blood vessels?

In angiography, a contrast agent specifically designed for vascular imaging is injected to enhance the visibility of blood vessels during the procedure. This contrast agent contains substances that can absorb X-rays or other forms of radiation, allowing radiologists to obtain clear images of the vascular structures. By providing a stark contrast between the blood vessels and the surrounding tissues, these agents make it possible to identify abnormalities such as blockages, aneurysms, or malformations within the vascular system.

The other options do not perform the necessary function that the contrast agent offers in the context of angiography. A saline solution might be used for hydration or even as a flush, but it wouldn’t provide the imaging clarity needed for vascular visualization. Local anesthetics are primarily for patient comfort during procedures but do not contribute to imaging. Similarly, while radioisotopes have their applications in nuclear medicine for different types of imaging, they are not used in standard angiographic procedures, which rely on enhanced X-ray imaging through contrast agents. Therefore, the use of a specifically designed contrast agent is crucial for successful angiographic visualization of blood vessels.