angiography

Angiography is a medical imaging technique used to visualize the inside of blood vessels and organs of the circulatory system. It typically involves the introduction of a radiopaque contrast agent and the use of X-ray, computed tomography (CT), or magnetic resonance (MR) imaging to generate images of the vascular tree. Conventional catheter angiography is invasive: a catheter is inserted into an artery, usually through the groin or wrist, advanced to the target vessels, and contrast is injected while fluoroscopic X-ray images are acquired. Digital subtraction angiography (DSA) enhances image contrast by removing background structures.

Noninvasive alternatives include CT angiography (CTA) and MR angiography (MRA), which can image vessels without catheterization. Time-resolved or three-dimensional techniques improve visualization of flow, collateral circulation, and vessel morphology.

Indications include detection and characterization of vascular disease such as aneurysms, stenosis, occlusions, and arteriovenous malformations, as well as tumors. Angiography is also used to plan and guide interventions such as angioplasty, stenting, embolization, or surgical planning.

Procedure and safety: Preparation may include assessment of kidney function and allergy risk to contrast. The procedure is usually performed in a radiology suite with local anesthesia and sometimes sedation. Afterward, puncture-site care and hydration reduce complications.

Risks and limitations: contrast reactions, nephrotoxicity, radiation exposure, arterial injury or bleeding, infection, and, for cerebral angiography, rare strokes or neurologic events. Noninvasive methods (CTA, MRA) reduce some risks but may have lower spatial or temporal resolution.