Dissing, Bjørn Skovlund

Larsen, Rasmus

Ramsøy, Thomas

Skimminge, Arnold Jesper Møller

Here we investigate how regions in the Medial Temporal Lobe(MTL) in a dataset consisting of 13 di®erent people changes us- ing a Principal Component Analysis(PCA). The regions investigated are the Temporopolar, Parahippocampal, Entorhinal, Hippocampal, Perirhi- nal and Amygdalar regions. The MTL is located fairly deep in the brain where the contrast is quite low, and region-boundaries can be di±cult to ¯nd, which is why a shape guiding term would be helpful for a segmen- tation algorithm. An expert used an interactive tool to draw binary(1 inside and 0 out- side) Volumes Of Interests(VOI) for each of the 13 subjects. As the brain is symmetric, 12 VOIs has been drawn for each subject. A simultane- ous multi-shape rigid registration scheme, similar to the one used in [Tsai et al., 2004] was used on the training shapes to remove linearities. As these are binary shapes, a set-di®erence cost function is minimized be- tween all shapes. To represent shapes in the coupled shape model, signed distance maps(SDM) was used, [Tsai et al., 2004]. The eigen-problem was solved on the covariance matrix using svd, to ¯nd the eigenshapes and their magnitude. Seven modes of variation was extracted, represent- ing 75% of the total variance which each represents di®erent modes of variations. An interactive program was developed to investigate how the ¯rst seven modes changes the shapes. In ¯gures 1 to 3 the most signi¯cant mode is seen varying with §2¾ from the meanshape. Fig. 1. meanshape + 2¾ Fig. 2. meanshape Fig. 3. meanshape - 2¾ References [Tsai et al., 2004] Tsai, A.,Wells, W., Tempany, C., Grimson, E. og Willsky, A. (2004). Mutual information in coupled multi-shape model for medical image segmentation. Elsevier Science

Online Research Database In Technology

Coupled Shape Modeling of the MedialTemporal LobeBjørn Skovlund Dissing, Rasmus Larsen, Arnold Skimminge and ThomasRamsøyInformatics and Mathematical ModellingTechnical University of Denmark, Building 321DK-2800 Kgs. Lyngby, DenmarkAbstract. Here we investigate how regions in the Medial TemporalLobe(MTL) in a dataset consisting of 13 different people changes us-ing a Principal Component Analysis(PCA). The regions investigated arethe Temporopolar, Parahippocampal, Entorhinal, Hippocampal, Perirhi-nal and Amygdalar regions. The MTL is located fairly deep in the brainwhere the contrast is quite low, and region-boundaries can be difficult tofind, which is why a shape guiding term would be helpful for a segmen-tation algorithm.An expert used an interactive tool to draw binary(1 inside and 0 out-side) Volumes Of Interests(VOI) for each of the 13 subjects. As the brainis symmetric, 12 VOIs has been drawn for each subject. A simultane-ous multi-shape rigid registration scheme, similar to the one used in[Tsai et al., 2004] was used on the training shapes to remove linearities.As these are binary shapes, a set-difference cost function is minimized be-tween all shapes. To represent shapes in the coupled shape model, signeddistance maps(SDM) was used, [Tsai et al., 2004]. The eigen-problemwas solved on the covariance matrix using svd, to find the eigenshapesand their magnitude. Seven modes of variation was extracted, represent-ing 75% of the total variance which each represents different modes ofvariations. An interactive program was developed to investigate how thefirst seven modes changes the shapes. In figures 1 to 3 the most significantmode is seen varying with ±2σ from the meanshape.Fig. 1. meanshape + 2σ Fig. 2. meanshape Fig. 3. meanshape - 2σReferences[Tsai et al., 2004] Tsai, A., Wells, W., Tempany, C., Grimson, E. og Willsky, A. (2004).Mutual information in coupled multi-shape model for medical image segmentation.Elsevier Science.

Coupled Shape Modeling of the Medial Temporal Lobe

http://orbit.dtu.dk/ws/files/3648952/imm5149.pdf

Coupled Shape Modeling of the Medial Temporal Lobe

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology