Today, many catheter angiographic studies have been replaced by less invasive methods, such as Computed Tomography Angiography (CTA) that does not require that a catheter be inserted.

CTA is commonly used to:

• Examine the pulmonary arteries in the lungs to rule out pulmonary embolism, a serious but treatable condition.
• Visualize blood flow in the renal arteries (those supplying the kidneys) in patients with high blood pressure and those suspected of having kidney disorders. Narrowing (stenosis) of a renal artery is a cause of high blood pressure (hypertension) in some patients and can be corrected. A special computerized method of viewing the images makes renal CT angiography a very accurate examination. Also done in prospective kidney donors.
• Identify aneurysms in the aorta or in other major blood vessels. Aneurysms are diseased areas of a weakened blood vessel wall that bulges out — like a bulge in a tire. Aneurysms are life-threatening because they can rupture.
• Identify dissection in the aorta or its major branches. Dissection means that the layers of the artery wall peel away from each other—like the layers of an onion. Dissection can cause pain and can be life-threatening.
• Identify a small aneurysm or arteriovenous malformation inside the brain that can be life-threatening.
• Detect atherosclerotic disease that has narrowed the arteries to the legs.
• Detect thrombosis (clots) in veins, for example large veins in the pelvis and legs. Such clots can travel to the lungs and result in pulmonary embolism.

CTA is also used to detect narrowing or obstruction of arteries in the pelvis and in the carotid arteries, which bring blood from the heart to the brain. When a stent has been placed to restore blood flow in a diseased artery, CTA will show whether it is serving its purpose. Examining arteries in the brain may help reach a correct diagnosis in patients who complain of headaches, dizziness, ringing in the ears or fainting. Injured patients may benefit from CTA if there is a possibility that one or more arteries have been damaged. In patients with a tumor, it may be helpful for the surgeon to know the details of arteries feeding the growth.

For more information on CT Angiography visit the web site:
http://www.radiologyinfo.org/en/info.cfm?pg=angioct

Magnetic Resonance Angiography (MRA)

Magnetic resonance imaging (MRI) is a method of producing extremely detailed pictures of body tissues and organs without the need for x-rays. The electromagnetic energy that is released when exposing a patient to radiofrequency waves in a strong magnetic field is measured and analyzed by a computer, which forms two- or three-dimensional images that may be viewed on a TV monitor. MR angiography (MRA) is an MRI study of the blood vessels. It utilizes MRI technology to detect, diagnose and aid the treatment of heart disorders, stroke, and blood vessel diseases. MRA provides detailed images of blood vessels without using any contrast material, although a special form of contrast material is often given to make the MRI images even clearer. The procedure is painless, and the magnetic field is not known to cause tissue damage of any kind.

Common uses of MRA:

• The carotid arteries in the neck that conduct blood to the brain are a common site of atherosclerosis, which may severely narrow or block off an artery, reducing blood flow to the brain and even causing a stroke. If an ultrasound study shows that such disease is present, many surgeons will perform the necessary operation after confirmation with MRA, dispensing with the need for catheter angiography.
• MRA has found wide use in checking patients for diseased intracranial (in the head) arteries, so that only those with positive findings will need to undergo a more invasive catheter study.
• MRA is also used to detect disease in the aorta and in blood vessels supplying the kidneys, lungs and legs.
• Patients with a family history of arterial aneurysm, a ballooning out of a segment of the vessel wall, can be screened with MRA to see if they have a similar disorder that has not produced symptoms. If an aneurysm is found, it may be eliminated surgically, possibly avoiding serious or fatal bleeding.

For more information on MR Angiography visit the web site:
http://www.radiologyinfo.org/en/info.cfm?pg=angiomr