Value of Three-Dimensional Reconstructions in Evaluating Thoracic Aortic Aneurysms
Aneurysms of the thoracic aorta may be difficult to assess with conventional digital subtraction angiography because it is a projection-based technique. Alternatively, spiral computed tomography (CT) angiography is limited because it does not allow slice orientation and a panoramic view. Post-processing techniques, such as volume rendering (VR), can generate three-dimensional (3D) images from a spiral CT data set. Tissues of interest can be selectively enhanced by adjusting densities to optimize their evaluation. Furthermore, 3D techniques allow presentation of multiplanar reformatted images, such as curved sections of the vascular lumen along the vessel course.
The images presented are of the thoracic aorta in a 24-year-old man with Marfan’s disease and previous aortic valve replacement. Spiral CT examination was performed with a single detector scanner, and the images were sent to a dedicated workstation. The patient underwent conventional catheter arteriography, with placement of 3 endovascular stent-grafts from the left subclavian artery to the celiac trunk.
VR allows a panoramic view of the thoracic aorta (Figures 1 and 2⇓ and Movies I through III). Moreover, the spatial relationships among surrounding structures are clearly visualized. Multiplanar images allow precise measurements.
In conclusion, 3D techniques should be routinely used for preoperative and follow-up evaluations of thoracic aortic aneurysms.
Movies I, II, and II are available as an online-only Data Supplement at http://www.circulationaha.org.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
Circulation encourages readers to submit cardiovascular images to the Circulation Editorial Office, St Luke’s Episcopal Hospital/Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.