Flat-detector computed tomography with intravenous contrast material application in experimental aneurysms: comparison with multislice CT and conventional angiography

Abstract

Background: Despite limited soft tissue resolution flat-detector computed tomography (FD-CT) provides substantial superior spatial resolution in comparison with multislice computed tomography (MS-CT). This may add value in the visualization of small vascular structures if intravenous contrast application leads to substantial opacification and visibility of intracranial vessels or aneurysms.

Purpose: To evaluate the feasibility of visualization of vascular structures by FD-CT angiography (FD-CTA) after intravenous contrast injection compared with MS-CTA and intra-arterial digital subtracted angiography (IADSA) in an animal model.

Material and methods: Aneurysms were created in the right common carotid artery in six New Zealand White Rabbits using the elastase technique. Imaging was performed using FD-CTA, MS-CTA (injection of 1 ml/kg body weight) and IADSA. Anonymized volume rendering reconstruction (VRT), maximum intensity projection (MIP), and multiplanar reconstruction (MPR) images were reconstructed and evaluated by two experienced reviewers for aneurysm geometry and vascular structure anatomy using standard tools of a dedicated workstation.

Results: Aneurysms could be successfully created in all animals. Measurements of aneurysm geometry (aneurysm height, width, neck width) and vascular structures (brachiocephalic trunk, carotid artery diameter and plane) were nearly identical in all three modalities. Intra- and inter-observer correlations of the different parameters showed high r values between 0.83 and 0.99.

Conclusion: Our results show the feasibility of FD-CTA in comparison with MS-CTA and IADSA in an animal model. Despite limited soft tissue resolution, opacification of vascular structures with sufficient contrast to the surrounding structures was possible in all animals. Vascular structures appeared better delineated in FD-CTA than in MS-CTA, probably due to the superior spatial resolution.