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Lower spine and pelvis

The vertebrae of the spi ne and the thick hip bones are easy to see on this X-ray. The tailbone of the spine can be seen faintly in the hollow between the hip bones.

Angiography

Angiography is an imaging procedure used to examine blood vessels, particularly arteries (arteriography). Angiograms can help doctors diagnose blood vessel disorders and are frequently performed before surgery on a blood vessel to locate the sites of blockages or other problems. Before an angiogram, a contrast medium (dye) containing iodine (which shows up on X-rays) is injected through a thin, flexible tube (catheter) inserted through a small incision into the femoral artery in the groin, the brachial artery in the elbow, or one of the carotid arteries in the neck. A rapid series of X-ray pictures is then taken of the arteries. Any abnormalities in the arteries will show up on the X-rays.

Magnetic resonance angiography (MRA) uses MRI (page 113) with angiography. In MRA, specific radio-pulse sequences are used (usually without using X-rays and usually without injecting a contrast medium) to create and enhance images.

THE PROCEDURE

If you are having an angiogram, you will be asked to lie very still on an examining table. The area in which the catheter is inserted will be numbed with an anesthetic. A needle is inserted through the skin into the artery, and a long, thin wire with a soft tip is inserted through the needle. The needle is then removed and the catheter threaded over the wire into the blood vessel. When the contrast medium is injected, you will feel a sensation of warmth for a few seconds. The procedure lasts from a few minutes to a few hours. After the examination, you may be asked to lie still for a few hours. Angiography poses a slight risk of damage to blood vessels (at the site of the injection or anywhere along the blood vessel during passage of the catheter) and a risk of an allergic reaction to the contrast medium.

Aneurysm in a carotid artery

This angiogram reveals an aneurysm, an abnormal ballooning of a weakened area in the wall of an artery (red area on left), as viewed from the back of the head. This aneurysm is in a carotid artery (one of two main arteries that supply blood to the head and neck). If an aneurysm in the brain ruptures, it can cause a stroke.

Narrowed coronary artery An angiogram of the arteries of the heart (called a cardiac arteriogram) is used to diagnose heart disease. In this image, the contrast medium reveals a narrowed section in the left coronary artery (arrow) that has reduced blood flow to that part of the heart muscle. A total blockage can cause a heart attack. The long, pink, unbroken areas in the image are healthy blood vessels.

Inflamed arteries in legs

This angiogram (taken with MRA) shows diseased arteries (dark pink areas) in the legs of a person with arteritis (inflammation in the walls of the arteries). The arteries in the legs originate in the iliac arteries of the groin (the groin is the brownish, circular area at top center).

Arteries to the kidneys

The arteries that supply blood to the kidneys (the renal arteries) are red in this angiogram. The kidneys appear yellow. The renal arteries branch off the abdominal aorta (the large red blood vessel running vertically down the center of the image). The vertebrae of the spine and several ribs are barely visible.

Ultrasound

Ultrasound is an imaging procedure that uses high-frequency sound waves to produce an image. Although ultrasound was initially used to view fetuses, it is now used to examine every organ of the body, including the heart (an echocardiogram). Because ultrasound does not pose a risk of exposure to radiation, it is increasingly taking the place of conventional X-rays (see page 109) for diagnosing many different conditions. In ultrasound, sound waves are directed into the body through a wandlike device called a transducer, which is moved around the skin over the area to be examined. Ultrasound produces clear images of soft tissues and