can form in communication with essentially any artery in the body. With the high volume of cardiac catheterizations performed today, femoral artery pseudoaneurysms, in addition to pseudoaneurysms of arteriovenous fistulas used for hemodialysis, are the most common. Pseudoaneurysms can form in the legs days, months, or even years after blunt or penetrating trauma. Although aneurysms and left ventricular aneurysms may involve any wall segment, "aneurysms" in the posterolateral wall are frequently due to pseudoaneurysms. In contrast, the most common location for a true left ventricular aneurysm involves the apex of the heart. A pseudoaneurysm can also occur in the aorta as a consequence of traumatic aortic rupture. Outside of the heart, pseudoaneurysms associated with pancreatitis can occur in several of the abdominal vessels, including the superior mesenteric artery, superior pancreaticoduodenal artery, inferior pancreaticoduodenal artery, and others. Treatment Many options exist for the treatment of pseudoaneurysms. While surgery was the gold-standard treatment in the past, several less-invasive treatment options are popular today. Covered stent Since the pseudoaneurysm communicates with an artery through a hole in the arterial wall, a covered stent may be placed endovascularly across this hole to "exclude it," or to prevent it from receiving blood flow from the artery. The covered stent is composed of metal and is covered with Teflon (PTFE) or another sterile fabric-like material. The covered stent remains in place permanently, and the pseudoaneurysm, without a continuous flow of arterial blood, then thromboses. Advantages of this technique are that it has a high success rate without the need for an open surgery. Complications include covered stent migration, persistent leakage of blood into the pseudoaneurysm, fracturing (breaking) of the stent, and infection of the stent or of the arterial insertion site. Ultrasound probe compression Another option for treatment is ultrasound probe compression of the neck of the pseudoaneurysm. The "neck" of the pseudoaneurysm is the narrow path of blood flow between the artery, through the arterial wall, and into the pseudoaneurysm cavity. The artery, neck, and pseudoaneurysm are seen on ultrasound. The ultrasound probe can be pushed firmly against the patient's skin to compress the neck of the pseudoaneurysm for usually about 20 minutes. During this time, the blood within the pseudoaneurysm clots; after the probe is then removed, the pseudoaneurysm will hopefully remain clotted and will not continue to expand. The procedure may be stopped early due to patient discomfort. It is less successful if