Endoleak Types in Radiology Endoleak Types in Radiology
Endoleak Types in Radiology Endoleak Types in Radiology
An endoleak is a complication that can occur following endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAA), and understanding its types is crucial for accurate diagnosis and management. Essentially, an endoleak refers to the persistent blood flow outside the lumen of the endograft but within the aneurysm sac, which can jeopardize the success of the repair by allowing continued aneurysm expansion and potential rupture. Radiologists play a vital role in detecting and classifying endoleaks through various imaging modalities, primarily computed tomography angiography (CTA), duplex ultrasonography, and magnetic resonance angiography (MRA). Endoleak Types in Radiology Endoleak Types in Radiology
Endoleaks are classified into five main types based on their source and pathophysiology. Type I endoleaks occur due to an inadequate seal at the proximal or distal attachment sites of the graft, leading to direct flow into the aneurysm sac. These are considered high-risk and often require urgent intervention because they can cause rapid aneurysm expansion. On imaging, they are characterized by contrast extravasation at the graft ends, often seen on CTA as a jet of contrast entering the sac during arterial phase imaging.
Type II endoleaks are the most common and result from retrograde flow into the aneurysm sac via branch vessels, such as lumbar arteries, the inferior mesenteric artery, or accessory renal arteries. They are frequently incidental findings on follow-up imaging and tend to have a benign course, although persistent or enlarging sacs may necessitate treatment. On imaging, they appear as slow, persistent contrast pooling within the sac during delayed phases.
Endoleak Types in Radiology Endoleak Types in Radiology Type III endoleaks are caused by defects or separations in the endograft fabric or modular disconnections between components of the graft. These leaks create direct communication from the systemic circulation into the aneurysm sac, posing a significant risk of rupture if not addressed. On imaging, they are evident as contrast flowing through discontinuities in the graft material, often seen during the arterial phase.
Type IV endoleaks are due to the inherent porosity of the graft material, leading to blood seepage through the fabric. They are typically seen immediately after deployment and tend to resolve spontaneously as the graft endothelizes. Imaging features are subtle, showing diffuse, low-flow contrast within the sac without a distinct jet, often difficult to distinguish from other leak types. Endoleak Types in Radiology Endoleak Types in Radiology
Type V, or endotension, is a somewhat controversial category where the aneurysm sac enlarges without any detectable leak on imaging. The etiology is unclear but may involve transudation of blood products or pressure transmission through the graft. Diagnosis is primarily exclusionary, based on serial imaging. Endoleak Types in Radiology Endoleak Types in Radiology
Detecting and accurately classifying endoleaks is essential for guiding appropriate management, whether it involves surveillance, endovascular re-intervention, or surgical repair. Radiological assessment must be meticulous, with multiphase CTA being the gold standard for its high sensitivity and specificity. Understanding the distinct imaging features of each endoleak type enables clinicians to tailor their treatment strategies effectively, ultimately improving patient outcomes.
Endoleak Types in Radiology Endoleak Types in Radiology In summary, the classification of endoleaks into five types reflects their underlying mechanisms and guides clinical decision-making. Continuous advancements in imaging techniques and materials used in EVAR are aimed at reducing their incidence and enhancing early detection.
