Vascular radiology is a type of interventional radiology, which uses image guidance methods to gain access to and view most organs, and organ systems, for diagnostic or treatment purposes. Images are used to direct interventional procedures, which are usually done with needles and catheters (narrow tubes). Through a wide range of minimally invasive techniques, certain conditions can be treated through the skin that might otherwise require surgery. The technology includes the use of balloons, catheters, stents (small tubes), and other devices. Common interventional imaging technologies include fluoroscopy (a type of X-ray), CT, ultrasound and MRI. Common vascular radiology procedures may include: angiography (imaging blood vessels to look for abnormalities with the use of various contrast media injected into veins); balloon angioplasty/stent (opening narrowed or blocked blood vessels using a tiny balloon, and sometimes placing a stent); embolisation (e.g. blocking abnormal blood vessels to stop bleeding); and thrombolysis (to dissolve blood clots).