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An individual representative target brain in Talairach space
NemoImage
13, Number
6, 2001, Part 2 of 2 Parts ID
Eal@
METHODS
- ANALYSIS
An Individual RepresentativeTarget Brain in Talairach Space Jack Lancaster, Peter Kochunov, Peter Fox
University of Texas Health Science Center at San Antonio, Research Imaging Center Background Target brains are used to transform individual images to a standard brain space. An individual target, as in the 1988 Talairach atlas [l], or an average target, as the MN1305 average [2], are common. An individual high-resolution target is desirable for high degree-of-freedom warping but may lead to bias in anatomical studies. To overcome this problem, we developed methods for defining, constructing, and evaluating a “minimal-deformation target” (MDT) brain for a group [3]. The goal was to provide a standard, reproducible target image with features common to the group. The product of mean deformation and dispersion distance, derived from deformation fields, was used to formulate a cost function. A best individual target (BIT) brain was determined, maximally homologous with anatomical features of the group. The BIT brain, transformed using an average deformation field, resulted in a single target brain, representative of the group. We used this processing strategy to make a representative target brain for Talairach space. Methods Twenty Tl-weighted anatomical 3-D MR images were selected from a group of healthy volunteers (8 males, 12 females; 19-31 years) in the ICBM project [4]. All brain images were globally spatially normalized using Convex Hull software [5]. Brains were analyzed to find the BIT. It was MDT transformed to a representative target brain [3]. Key distance measures and locations of the AC and PC were compared with published values for the Talairach atlas [5].
An individual target brain for Talairach space was created. This 3-D MR target brain image can be used with various spatial normalization Talairach space. Work is underway to create a complete brain model (including contributing brains. Table.
Dimensions
of Representative
Landmark Left Right Front-to-back Top-to-bottom Distances relative
and Talairach
applications cerebellum)
to transform and increase
brain images to the number of
Brain Representative 69 mm 68 mm 174mm 116mm
brain
Talairach
brain
-68 mm 68 mm 172mm 118mm
to AC.
References 1. Talairach .I, Toumoux P(1988). Co-Planar Stereotaxic Atlas of the Human Brain. New York Thieme Medical Publishers. 2. Evans A, Collins D, Holmes C (1996). Computational approaches to quantifying human neuroanatomical variability. In “Brain Mapping: The Methods” (Toga A., Mazziotta J. Eds.) pp. 343-361. Academic Press. 3. Kochunov P, Lancaster J, Thompson P, et al (2000). Regional Spatial Normalization: Towards the Optimal Target. JCAT. In review. 4. Mazziotta JC, Toga AW, Evans A, et al (1995). A probabilistic atlas of the human brain: theory and rationale for its development. Neuroimage 2:89-101. 5. Lancaster JL, Fox PI, Downs H, et al (1999). Global spatial normalization of the human brain using convex hulls. J Nucl Med, 40(6):942-955.
S180
13, Number
6, 2001, Part 2 of 2 Parts ID
Eal@
METHODS
- ANALYSIS
An Individual RepresentativeTarget Brain in Talairach Space Jack Lancaster, Peter Kochunov, Peter Fox
University of Texas Health Science Center at San Antonio, Research Imaging Center Background Target brains are used to transform individual images to a standard brain space. An individual target, as in the 1988 Talairach atlas [l], or an average target, as the MN1305 average [2], are common. An individual high-resolution target is desirable for high degree-of-freedom warping but may lead to bias in anatomical studies. To overcome this problem, we developed methods for defining, constructing, and evaluating a “minimal-deformation target” (MDT) brain for a group [3]. The goal was to provide a standard, reproducible target image with features common to the group. The product of mean deformation and dispersion distance, derived from deformation fields, was used to formulate a cost function. A best individual target (BIT) brain was determined, maximally homologous with anatomical features of the group. The BIT brain, transformed using an average deformation field, resulted in a single target brain, representative of the group. We used this processing strategy to make a representative target brain for Talairach space. Methods Twenty Tl-weighted anatomical 3-D MR images were selected from a group of healthy volunteers (8 males, 12 females; 19-31 years) in the ICBM project [4]. All brain images were globally spatially normalized using Convex Hull software [5]. Brains were analyzed to find the BIT. It was MDT transformed to a representative target brain [3]. Key distance measures and locations of the AC and PC were compared with published values for the Talairach atlas [5].
An individual target brain for Talairach space was created. This 3-D MR target brain image can be used with various spatial normalization Talairach space. Work is underway to create a complete brain model (including contributing brains. Table.
Dimensions
of Representative
Landmark Left Right Front-to-back Top-to-bottom Distances relative
and Talairach
applications cerebellum)
to transform and increase
brain images to the number of
Brain Representative 69 mm 68 mm 174mm 116mm
brain
Talairach
brain
-68 mm 68 mm 172mm 118mm
to AC.
References 1. Talairach .I, Toumoux P(1988). Co-Planar Stereotaxic Atlas of the Human Brain. New York Thieme Medical Publishers. 2. Evans A, Collins D, Holmes C (1996). Computational approaches to quantifying human neuroanatomical variability. In “Brain Mapping: The Methods” (Toga A., Mazziotta J. Eds.) pp. 343-361. Academic Press. 3. Kochunov P, Lancaster J, Thompson P, et al (2000). Regional Spatial Normalization: Towards the Optimal Target. JCAT. In review. 4. Mazziotta JC, Toga AW, Evans A, et al (1995). A probabilistic atlas of the human brain: theory and rationale for its development. Neuroimage 2:89-101. 5. Lancaster JL, Fox PI, Downs H, et al (1999). Global spatial normalization of the human brain using convex hulls. J Nucl Med, 40(6):942-955.
S180