Combination Strategies in Multi-Atlas Image Segmentation: Application to Brain MR Data Articles uri icon

publication date

  • August 2009

start page

  • 1266

end page

  • 1277

issue

  • 8

volume

  • 28

International Standard Serial Number (ISSN)

  • 0278-0062

Electronic International Standard Serial Number (EISSN)

  • 1558-0062

abstract

  • It has been shown that employing multiple atlas images improves segmentation accuracy in atlas-based medical image segmentation. Each atlas image is registered to the target image independently and the calculated transformation is applied to the segmentation of the atlas image to obtain a segmented version of the target image. Several independent candidate segmentations result from the process, which must be somehow combined into a single final segmentation. Majority voting is the generally used rule to fuse the segmentations, but more sophisticated methods have also been proposed. In this paper, we show that the use of global weights to ponderate candidate segmentations has a major limitation. As a means to improve segmentation accuracy, we propose the generalized local weighting voting method. Namely, the fusion weights adapt voxel-by-voxel according to a local estimation of segmentation performance. Using digital phantoms and MR images of the human brain, we demonstrate that the performance of each combination technique depends on the gray level contrast characteristics of the segmented region, and that no fusion method yields better results than the others for all the regions. In particular, we show that local combination strategies outperform global methods in segmenting high-contrast structures, while global techniques are less sensitive to noise when contrast between neighboring structures is low. We conclude that, in order to achieve the highest overall segmentation accuracy, the best combination method for each particular structure must be selected.

keywords

  • image segmentation; voting; biomedical imaging; cancer; fuses; imaging phantoms; humans; level set; scholarships; atlas-based segmentation; classifier combination; combination of segmentations; majority voting; weighted voting; classifiers; digital image storage; learning systems; image segmentation; algorithm; article; brain; factual database; histology; human; image processing; image quality; methodology; nuclear magnetic resonance imaging; statistical analysis; algorithms; data interpretation; statistical; computer assisted; magnetic resonance imaging