Local and Remote Visualization Techniques for Interactive Direct Volume Rendering in Neuroradiology

Abstract

The increasing capabilities of magnetic resonance (MR) imaging and multisection spiral computed tomography (CT) to acquire volumetric data with near-isotropic voxels make three-dimensional (3D) postprocessing a necessity, especially in studies of complex structures like intracranial vessels. Since most modern CT and MR imagers provide limited postprocessing capabilities, 3D visualization with interactive direct volume rendering requires expensive graphics workstations that are not available at many institutions. An approach has been developed that combines fast visualization on a low-cost PC system with high-quality visualization on a high-end graphics workstation that is directly accessed and remotely controlled from the PC environment via the Internet by using a Java client. For comparison of quality, both techniques were applied to several neuroradiologic studies: visualization of structures related to the inner ear, intracranial aneurysms, and the brainstem and surrounding neurovascular structures. The results of pure PC-based visualization were comparable with those of many commercially available volume-rendering systems. In addition, the high-end graphics workstation with 3D texture-mapping capabilities provides visualization results of the highest quality. Combining local and remote 3D visualization allows even small radiologic institutions to achieve low-cost but high-quality 3D visualization of volumetric data.

CT Angiography of Intracranial Aneurysms: A Focus on Postprocessing

“…The basic principle is to select several groups of voxels according to their attenuation in Hounsfield units and to assign them a color and a so-called opacity (28,29) (Fig 7). When dVR is used to create CT angiograms, the voxels of high attenuation containing information about bony structures are selected separately from those voxels with an attenuation between 100 and 300 HU containing information about contrast-enhanced vascular structures.…”

“…Unfortunately, the quality of dVR highly depends on many factors like the quality of the workstation and the applied rendering algorithm (29). Therefore, dVR is not a unique method and available studies are still not comparable.…”

Three-dimensional visualization of neurovascular relationships in the posterior fossa: technique and clinical application

“…Nonetheless, this is misleading 7,10,20,28,44 in terms of computer graphics, because 3D visualization comprises all methods of volume rendering, which allow us to extract and show 3D representations of 3D imaging data (for example, MR imaging volumes). 1,6,14,15,42,43 The resulting illustrations should provide 3D objects that are close to reality based on the underlying imaging data. 2,5,14,16,36,43 Attempts at 3D visualization have been made in two studies, but neither of them presented any details about the applied principles and methods of image Object.…”

Craniotomia dirigida por tomografia computadorizada com reconstrução tridimensional: nota técnica

“…Imagens tomográficas convencionais podem ser p ó s -p rocessadas em imagens 3D, pro p o rc i o n a n d o melhor noção espacial da anatomia, levando a um efeito muito semelhante às peças anatômicas e a própria situação operatória que será encontrada pelo cirurgião [10][11][12][13][14] .…”