Define "digital subtraction angiography."

Digital subtraction angiography refers to a specialized imaging technique that focuses on visualizing blood vessels, primarily the vascular structures within the body. This methodology employs a digital imaging process where a series of images are taken before and after the contrast agent is introduced into the bloodstream. The key aspect is that the first set of images, which contains all the surrounding structures such as bones and soft tissues, serves as a baseline or background.

Once the images are captured, the system subtracts the background information from the image taken after the contrast medium is injected. This subtraction effectively leaves behind only the images of the blood vessels, providing a clear and detailed view of their anatomy and any potential abnormalities. This clarity is crucial for diagnostic purposes, enabling healthcare professionals to identify issues like blockages, aneurysms, or other vascular conditions.

The other options, while relating to medical imaging or therapy, do not accurately describe digital subtraction angiography. Specifically, it does not pertain to imaging bones, radiation therapy, or advanced MRI techniques for muscle imaging; instead, it is distinctly about the enhanced visualization of blood vessels through the process of digitally subtracting unnecessary background data.