The hippocampus has been known to be an important structure as a biomarker for Alzheimer's disease (AD) and other neurological and psychiatric diseases. However, it requires accurate, robust and reproducible delineation of hippocampal structures. In this study, an automated hippocampal segmentation method based on a graph-cuts algorithm combined with atlas-based segmentation and morphological opening was proposed. First of all, the atlas-based segmentation was applied to define initial hippocampal region for a priori information on graph-cuts. The definition of initial seeds was further elaborated by incorporating estimation of partial volume probabilities at each voxel. Finally, morphological opening was applied to reduce false positive of the result processed by graph-cuts. In the experiments with twenty-seven healthy normal subjects, the proposed method showed more reliable results (similarity index. = 0.81. ±. 0.03) than the conventional atlas-based segmentation method (0.72. ±. 0.04). Also as for segmentation accuracy which is measured in terms of the ratios of false positive and false negative, the proposed method (precision. = 0.76. ±. 0.04, recall. = 0.86. ±. 0.05) produced lower ratios than the conventional methods (0.73. ±. 0.05, 0.72. ±. 0.06) demonstrating its plausibility for accurate, robust and reliable segmentation of hippocampus.
Bibliographical noteFunding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology ( 2011-0014862 ). This work was also supported by the Korea Science and Engineering Foundation (KOSEF) NLRL program grant funded by the Korean Government (MEST) ( 2011-0028333 ).
- Atlas-based segmentation
- Graph cuts algorithm
- Magnetic Resonance Imaging
- Morphological operation
- Partial volume estimation