How many templates does it take for a good segmentation?: error analysis in multiatlas segmentation as a function of database size

  • Authors:
  • Suyash P. Awate;Peihong Zhu;Ross T. Whitaker

  • Affiliations:
  • Scientific Computing and Imaging (SCI) Institute, University of Utah;Scientific Computing and Imaging (SCI) Institute, University of Utah;Scientific Computing and Imaging (SCI) Institute, University of Utah

  • Venue:
  • MBIA'12 Proceedings of the Second international conference on Multimodal Brain Image Analysis
  • Year:
  • 2012

Quantified Score

Hi-index 0.00

Visualization

Abstract

This paper proposes a novel formulation to model and analyze the statistical characteristics of some types of segmentation problems that are based on combining label maps / templates / atlases. Such segmentation-by-example approaches are quite powerful on their own for several clinical applications and they provide prior information, through spatial context, when combined with intensity-based segmentation methods. The proposed formulation models a class of multiatlas segmentation problems as nonparametric regression problems in the high-dimensional space of images. The paper presents a systematic analysis of the nonparametric estimation's convergence behavior (i.e. characterizing segmentation error as a function of the size of the multiatlas database) and shows that it has a specific analytic form involving several parameters that are fundamental to the specific segmentation problem (i.e. chosen anatomical structure, imaging modality, registration method, label-fusion algorithm, etc.). We describe how to estimate these parameters and show that several brain anatomical structures exhibit the trends determined analytically. The proposed framework also provides per-voxel confidence measures for the segmentation. We show that the segmentation error for large database sizes can be predicted using small-sized databases. Thus, small databases can be exploited to predict the database sizes required ("how many templates") to achieve "good" segmentations having errors lower than a specified tolerance. Such cost-benefit analysis is crucial for designing and deploying multiatlas segmentation systems.