Survey of Labeling Techniques in Medical Visualizations

Abstract

Annotations of relevant structures and regions are crucial in diagnostics, treatment planning, medical team meetings as well as in medical education. They serve to focus discussions, present results of collaborative decision making, record and forward diagnostic findings, support orientation in complex or unfamiliar views on the data, and study anatomy. Different techniques have been presented for labeling the original data in 2D slice views, surface representations of structures extracted from the data, e.g., organs and vasculature, and 3D volume rendered representations of the data. All aim at a clear visual association of labels and structures, visible and legible labels, and a fast and aesthetic labeling while considering individual properties of the data and its representation and tackling various issues, e.g., occlusion of structures by labels, overlapping labels, and crossings of lines connecting labels with structures. We survey the medical labeling work and propose a classification with respect to the employed labeling technique. We give guidelines for choosing a technique dependent on the data representation, e.g., surface rendering or slice view, the type of structures to be labeled, and the individual requirements on an effective label layout.