Cardiothoracic Image Postprocessing

Abstract

Image postprocessing is the use of imaging techniques either to derive additional information from the original axial images of a CT scan or to hide unwanted information that distracts from the clinical findings. The basis for image postprocessing is a three-dimensional image volume, which in most cases consists of a stack of individual axial images. The fundamental three-dimensional unit in this volume is called a “voxel.” Ideally, the spatial resolution of volume image data is high and isotropic, i.e., each voxel is of equal dimensions in all three spatial axes. Isotropic sub-millimeter resolution is the basis for image display in arbitrarily oriented imaging planes and advanced image postprocessing techniques. With the advent of multi-detector row CT (MDCT) and its ongoing refinement, isotropic sub-millimeter voxels can be obtained for the majority of clinical examinations, improving the diagnostic quality of image postprocessing and turning it into a vital component of medical imaging today, in particular for CT angiography (Prokop et al. 1997; Rankin 1999; Addis et al. 2001; Lawler et al. 2002).