Endovascular repair of descending thoracic aortic aneurysm is an attractive approach. Candidates for endovascular repair should have an inner aortic diameter of 23-37 mm adjacent to the aneurysm without signifi cant thrombus or calcifi cation in these so called landing zones. They should have at least 2 cm of normal aorta both proximal and distal to the aneurysm to ensure adequate fi xationof the divece. Endografting of the descending thoracic aorta requires preoperative measurements of the diameter of the proximal and distal necks of the aneurysm, tratment length, and proximal and distal angulation. This information can be obtained from CT-ic angiography using three dimensional reconstruction.