Pseudoaneurysm of the abdominal aorta: evaluation with virtual angioscopy of spiral-CT data sets.

We describe a case of graft-related pseudoaneurysm of the abdominal aorta evaluated with spiral CT and DSA. Spiral CT data sets were processed to obtain surface-rendered internal views (virtual angioscopy, VA) of the graft and the pseudoaneurysm, and to demonstrate from inside the lumen the site of dehiscence. A jet flow phenomenon inside the pseudoaneurysm was observed at DSA. Spiral-CT axial images, multiplanar volume reconstructions with maximum intensity projections, and shaded surface display showed the site of rupture. The VA findings were: (a) from inside the graft lumen, the evidence of a communication canal between the graft and the pseudoaneurysm; and (b) from inside the pseudoaneurysm, the presence of a jet flow. The VA findings showed good correlation with those obtained with the other imaging techniques.

Detection of accessory renal arteries with virtual vascular endoscopy of the aorta.

PURPOSE: To evaluate the diagnostic accuracy of virtual vascular endoscopy (VVE) in the detection of accessory renal arteries. METHODS: We retrospectively reviewed the CT angiography data sets of 67 patients (29 male and 38 female; age range 17-72 years, mean age 53 years) imaged for the study of the renal arteries, and affected by renovascular hypertension. All patients also had intraarterial digital subtraction angiography (DSA). CT angiography data sets were processed to obtain maximum intensity projection (MIP) and surface-rendered VVE of the aorta. Axial images, MIP, and VVE were evaluated separately and in combination in the detection of accessory renal arteries. Their results in terms of sensitivity and specificity were then compared with DSA. RESULTS: Axial images had a sensitivity of 88% and specificity of 94% for accessory renal artery detection, MIP had a sensitivity of 88% and specificity of 98%, and VVE had a sensitivity of 63% and a specificity of 88% (p < 0.05 vs DSA), but these increased to 88% and 98% respectively if endoscopic views were integrated with the other display techniques. CONCLUSION: VVE based on surface rendering does not add substantial benefits to CTY angiography; by contrast MIP is the most accurate display technique for the detection of accessory renal arteries.