Which procedure involves taking a series of radiographs after injecting contrast material into a vessel?

The procedure that involves taking a series of radiographs after injecting contrast material into a vessel is known as an angiogram. This imaging technique is specifically designed to visualize blood vessels and can help in diagnosing conditions related to the cardiovascular system. By using a contrast dye, the angiogram enhances the visibility of the vessels during imaging, making it easier for healthcare professionals to identify blockages, aneurysms, or other vascular abnormalities.

In contrast, the other terms listed refer to different medical concepts. Anorexia pertains to a loss of appetite, aphasia refers to a communication disorder that affects a person's ability to process and use language, and aphagia is the inability to swallow. None of these terms are related to the imaging of blood vessels, which distinctly identifies angiography as the correct answer.