Influence of geometric and hemodynamic parameters on aneurysm visualization during three-dimensional rotational angiography: an in vitro study.

BACKGROUND AND PURPOSE Aneurysm depiction with three-dimensional (3D) rotational angiography is influenced by investigator-defined parameters such as image acquisition and contrast agent injection and by the hemodynamic pattern in the parent artery and aneurysm. To assess the impact of the geometric configuration of parent artery and aneurysm on the 3D visualization of saccular aneurysms, we studied silicone aneurysm models under pulsatile-flow conditions. METHODS Rotational angiography was performed in three bifurcation and three lateral aneurysm models with ostia of different widths. Three acquisition modalities (5, 8, and 14 seconds in duration, acquisition rate of 10 frames per second) and two techniques for the injection of contrast material (continuous flow and injection with an initial bolus) were applied. 3D reconstructions were obtained with a volume-rendering technique. RESULTS Bifurcation aneurysms were visualized with high accuracy. Filling deficits distant to the inflow zone could be compensated for with the bolus-injection technique, and complete depiction of aneurysm shape was achieved in the 8-second rotation with 20 mL of contrast agent. In lateral aneurysms, the accuracy of 3D reconstructions depended on the width of the ostium. Although rotational studies in wide-necked lateral aneurysms yielded adequate reconstructions, 3D visualization of small-necked aneurysms was incomplete with the preferential depiction of the distal shell, which represents the inflow zone into the aneurysmal lumen. CONCLUSION Contrast agent injection with the initial-bolus technique improved the depiction of aneurysms, compared with the continuous-flow method. Reconstructions of rotational studies of narrow-necked lateral aneurysms yielded incomplete visualization of the aneurysm.