A radiologist is a medical doctor who specializes in the use and interpretation of Xrays, ultrasounds and other diagnostic tests such as CT or MRI scans. An interventional radiologist is a radiologist with additional training. The interventional radiologist uses these diagnostic tools to help identify blood vessels or spaces within the body for the purpose of inserting catheters or drainage tubes or to perform procedures or treatments.
Critically ill patients usually undergo a number of diagnostics tests during their admission. Some tests can be performed at the bedside, while others require the patient to go to the radiology department. When a patient is taken to the radiology department to have a catheter inserted or a treatment performed that requires the use of diagnostic equipment, you may be told that the patient has gone to "interventional radiology".
An Angiogram is a type of xray that is done to look at blood vessels. Prior to taking the Xray, a special catheter is inserted into a large artery (usually in the groin) and advanced until it reaches the arteries we are interested in studying. Once the catheter is positioned at the entrance of the desired blood vessel, a dye is injected into the blood vessel. The dye (called contrast) appears white on an xray film . As the dye flows through the blood vessels, the blood vessel shape and diameter can be seen (Image 1).
Image 1: The aorta and femoral artery (which carries blood to the left leg) is highlighted by the use of contrast.
Angiograms can be used to look at most arteries in the body. A cerebral angiogram looks specifically at the blood vessles to the brain. A coronary angiogram, often called a Cardiac Catheterization or Heart Catherization (or Heart Cath) looks at the arteries of the heart.
Angiograms are done to identify disease of the arteries. They can detect narrowing or blockage of a vessel, aneurysms and/or bleeding from a vessel wall.
An angioplasty is a procedure that can be performed during an angiogram. During an angiogram, specially designed catheters with balloons can be inserted into a narrowed blood vessel. The balloon can be inflated to force the narrowed blood vessel to open (balloon angioplasty). A small stent (or "cage") can be inserted into the narrowed area to help keep it "splinted" open. This is often referred to as angioplasty with stenting.
Angiogram can be combined with other procedures. For example, certain types of aneurysms (a sac or bulge in a blood vessel wall) can be treated by feeding thin platinum coils into the neck of the aneurysm (called coiling). Once the aneurysm is filled with coils, blood flow into the aneurysm will stop. This reduces the chance that the aneurysm will rupture. This type of procedure can be very useful when the aneurysm if either hard to reach or in an area where surgery can be very dangerous (e.g., aneurysms in the brain).
Angiogram can be used to identify area of bleeding. Material that causes blood to clot can be injected into bleeding vessels. This is called catheter directed embolization. This type of procedure can sometimes identify bleeding from areas that are difficult to find during surgery. Catheter directed embolization can sometimes be used to avoid more invasive procures. For example, a lacerated spleen can cause life-threatening hemorrhage (severe bleeding). If the bleeding can be controlled by catheter directed embolization, the patient may be able to recover without needing to have their spleen removed.
Intraveneous contrast carries a risk of causing kidney damage. As well, some people are allergic to contrast. Before giving a patient contrast, we will ask about allergies and review the patient's kidney function. The potential risk of any test is always weighed against the possible benefits. If we have to give contrast to someone whose kidneys are at risk, we may administer fluid or medication before the test to help protect the kidney.