(Angiogram-Kidneys, Renal Angiography, Renal Arteriogram, Renal Arteriography)
What is a renal angiogram?
An angiogram, also called an arteriogram, is an x-ray image of the blood vessels. It is performed to evaluate various vascular conditions, such as an aneurysm (ballooning of a blood vessel), stenosis (narrowing of a blood vessel), or blockages.
A renal angiogram is an angiogram of the blood vessels of the kidneys. A renal angiogram may be used to assess the blood flow to the kidneys.
Fluoroscopy is often used during a renal venogram. Fluoroscopy is the study of moving body structures - similar to an x-ray "movie." A continuous x-ray beam is passed through the body part being examined, and is transmitted to a TV-like monitor so that the body part and its motion can be seen in detail.
How is an angiogram performed?
In order to obtain an x-ray image of a blood vessel, an intravenous (IV) access is necessary so that a contrast dye can be injected into the body's circulatory system. This contrast dye causes the blood vessels to appear opaque on the x-ray image, thus allowing the physician to better visualize the structure of the vessel(s) under examination.
Many arteries can be examined by an angiogram, including the arterial systems of the legs, kidneys, brain, and heart.
For a renal angiogram, IV access may be obtained through a large artery such as the femoral artery in the groin. Once IV access is obtained, the contrast dye is injected and a series of x-ray pictures is made. These x-ray images show the arterial, venous, and capillary blood vessel structures and blood flow in the kidneys.
Other related procedures that may be used to diagnose kidney problems include kidney, ureters, and bladder (KUB) x-ray, computed tomography (CT scan) of the kidneys, kidney biopsy, kidney scan, kidney ultrasound, and renal venogram. Please see these procedures for additional information.
How do the kidneys work?
The body takes nutrients from food and converts them to energy. After the body has taken the food that it needs, waste products are left behind in the bowel and in the blood.
The kidneys and urinary system keep chemicals, such as potassium and sodium, and water in balance, and remove a type of waste, called urea, from the blood. Urea is produced when foods containing protein, such as meat, poultry, and certain vegetables, are broken down in the body. Urea is carried in the bloodstream to the kidneys.
Two kidneys, a pair of purplish-brown organs, are located below the ribs toward the middle of the back. Their function is to:
remove liquid waste from the blood in the form of urine
keep a stable balance of salts and other substances in the blood
produce erythropoietin, a hormone that aids the formation of red blood cells
regulate blood pressure
The kidneys remove urea from the blood through tiny filtering units called nephrons. Each nephron consists of a ball formed of small blood capillaries, called a glomerulus, and a small tube called a renal tubule.
Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney.
Reasons for the Procedure
A renal angiogram may be performed to detect abnormalities of the blood vessels of the kidneys. Such abnormalities may include, but are not limited to, the following:
stenosis or vasospasm (spasm of the blood vessel)
arteriovenous malformation (an abnormal connection between the arteries and veins)
thrombosis (a blood clot within a blood vessel) or occlusion (blockage of a blood vessel)
renovascular hypertension (high blood pressure in the kidneys’ blood vessels)
Other conditions that may be detected by a renal angiogram include tumors, hemorrhage (bleeding), complications of kidney transplantation, and the invasion of a tumor into the blood vessels. Kidney failure and other chronic kidney diseases may be evaluated by a renal angiogram. An angiogram may be used to deliver medications directly into the tissue or organ needing treatment, such as the administration of a clotting medication to a bleeding site or cancer medication into a tumor.