Image visualization and post-processing techniques

Abstract

The application of imaging techniques to original axial images of a CT scan in order to derive additional information or hide unwanted information that distracts from the clinical findings is called image post-processing. Image post-processing requires modification of a 3D image volume, which in most cases consists of a stack of individual axial images. The fundamental 3D unit in this volume is called a «voxel». Ideally, volume image data are of high spatial resolution and isotropic in nature, i.e., each voxel is of equal dimensions in all three spatial axes, and forms the basis for image display in arbitrarily oriented imaging planes and advanced image postprocessing techniques. With the advent of multi-slice CT and its on-going refinement, isotropic sub-millimeter voxels can be obtained for the majority of clinical examinations. This has improved the diagnostic quality of image post-processing such that it has become a vital component of medical imaging today, in particular for CT angiography (Prokop 1997, Rankin 1999, Addis 2001). The axial source images contain the basic information of a CT scan. They can be supplemented by basic 3D post-process ing tools and advanced methods for the analysis of complex anatomy, automated quantification, and functional evaluation (Vogl 2002, van Ooijen 2003, de Feyter 2005). © 2007 Springer-Verlag Berlin Heidelberg.