Multidimensional visualization in echocardiography: an introduction.

X-ray films depict three-dimensional objects as shadows in a two-dimensional plane; thus, objects become superimposed. Computed tomography and other types of tomographic imaging, such as ultrasonography, acquire two-dimensional images of a material property within a thin slice. Sequential adjacent two-dimensional tomograms can be used to construct three-dimensional displays of objects. Visualization, a field of computer science, enables scientists to measure image attributes (extraction of features), identify features (classification), separate objects from one another (segmentation), and produce comprehensible, information-dense images from three-dimensional data sets (rendering). A three-dimensional rendering of the heart can be used to represent only one component of the heart, such as the atrial septum or the ventricular chamber, and can be shaded or colored to enhance comprehension. Three-dimensional images rendered sequentially over time result in a dynamic four-dimensional display. This report describes multidimensional visualization of objects and tissues and specifically discusses examples from echocardiography.