Standardized Evaluation of CT Angiography with Remote Generation of 3D Video Sequences for the Detection of Intracranial Aneurysms

Abstract

Computed tomography (CT) angiography is a well-known imaging technique commonly applied to both the detection and therapy planning of intracranial aneurysms. For this purpose, current studies predominantly focus on three-dimensional (3D) representations of CT angiographic volumes obtained with varying visualization approaches on different computers. Interactive manipulation performed by users individually is an important prerequisite for data analysis. However, this leads to inconsistent and barely reproducible 3D visualization results. Furthermore, the quality of any 3D representation depends on the applied visualization strategy (eg, maximum-intensity projection, shaded-surface display, direct volume rendering). To overcome these limitations, the authors present a novel method for standardized visualization of CT angiographic volumes, consisting of three steps: (a) transfer of the image data to a remote high-end graphics workstation, (b) automatic 3D visualization with high-resolution direct volume rendering, and (c) consecutive video generation performed according to a standardized protocol. The recorded video sequences are transferred for evaluation to a local desktop computer. In the experimental setup, high-quality videos based on 3D visualizations were produced in less than 60 minutes per patient. Although aneurysms above the skull base are usually visualized with excellent quality, the analysis of aneurysms at the skull base is still difficult.

CT Angiography of Intracranial Aneurysms: A Focus on Postprocessing

“…A model for a standardized postprocessing algorithm has been proposed by our research group (45). Our approach is based on an automated 3D image reconstruction generated by a remote high-end workstation.…”

Clinical evaluation of bone-subtraction CT angiography (BSCTA) in head and neck imaging

“…One reason may be that CTA is still not a uniformly standardized method, particularly with regards to image post-processing [26]. In one study, 57% of false negative findings were related to aneurysms located at or within the skull base, although they contributed to only 36% of all aneurysms [27]. An obvious explanation therefore is that infraclinoid aneurysms may be hidden by bone.…”

Adaptive Script Based Animations for Intervention Planning

“…Iserhardt-Bauer et al [7] generated simple clinical videos efficiently using standard views and visualizations parameters. Tomandl et al [8] evaluated the benefit of standardized high quality videos in clinical routine and state that those videos are a viable approach for standardized and reproducible visualizations. Facilities to improve interactive dataset traversal by animation of transfer functions for volume rendering were introduced by Correa et al [9].…”

“…4. Standardization: Animations for intervention planning should be standardized to afford comparisons and to facilitate the recognition of structures in different animations [7], [8], [10].…”

“…In the example the scene is introduced and all lymph nodes are emphasized according to their size while other structures like bones and muscles are toned down to give a little context information (Fig. 3): [1,7] 'Scene' introduce // rotating the scene 360 degrees [8,10] 'Lymphnodes' showBySize // show lymph nodes colored by size…”