Until recently open surgical repair was the only treatment option available for patients with abdominal aortic aneurysms. With the introduction and now widespread use of endovascular stent grafts, patients once considered poor surgical candidates are undergoing successful endovascular repair. With this technology comes great responsibility on imaging in order to plan the procedure. Each device must be measured specifically for the patient prior to the procedure. Measurements of import include the maximum aneurysm diameter, the length of the abdominal aorta, and the degree of tortuosity of the aorta. These factors must be taken into consideration in the planning of these procedures,
Fig. 1. Contrast enhanced MRA of the abdomen and pelvis Fig. 2. Sagittal reformat of an MRA of the abdomen and pelvis demonstrate an infrarenal AAA with bilateral common iliac demonstrates an infrarenal aneurysm with a severely angulated aneurysms (white arrows). Incidentally noted is a left renal artery neck (arrow) stenosis (black arrow)
as each device must conform to each individual patient to avoid possible complications. Routinely a 15mm proximal neck is required for adequate sealing. The endograft diameter is usually 2 to 3 mm larger than the vessel lumen. If the endograft diameter is too small or if the length of the proximal neck is too short, there may be an inadequate seal. An inadequate seal can lead to perigraft flow or en-doleak. Similarly, too large an endograft diameter may lead to folding of the graft, which can also lead to endoleak. Endografts that are too long or too short can lead to seal problems and ultimately to endoleaks, limb kinking or limb occlusion.
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.