Article
Surface-based morphing for visualisation of functional MRI
Oberflächen-Morphing zur Darstellung von f-MRT Daten
Search Medline for
Authors
Published: | April 23, 2004 |
---|
Outline
Text
Objective
The inter-individual variability of the complexities of cortical geography often impedes studies of functional specialisation. The display of functional data in the stereotactic space may lead to underestimation of the distance activated areas, as two points close to each other in stereotactic space can be distant in Euclidean space. In this study we discuss compensation strategies involving explicit reconstruction and display of cortical surfaces (including 3D native configuration, 2D slices, extensively smoothed surfaces, spherical representations and cortical flat maps).
Methods
Functional MRI studies of 7 patients during standardised paradigms for hand-, foot-, and tongue movements were performed and EPI T2* weighted images were acquired. Data analysis was done with the Brain Voyager software (Brain Innovation, Maastricht, NL) on a standard PC. Statistical maps for the time course of activated voxels and corresponding 3D surfaces were rendered. The data were reconstructed as native 3D surfaces, extremely smooth surfaces, spheres and flat maps. Each reconstruction class was evaluated in terms of visibility, surface topology, compactness, parameterisation and ease of localisation of the presented data.
Results
The functional motor areas were clearly visible in all reconstructed surfaces. Activation within the sulci was not visible in native 3D reconstruction, whereas these areas can clearly be displayed on the morphed surfaces. Inflated models and flat maps were superior in demonstrating the spatial extent of an activated area. For inter individual comparison, data mapping on well-defined geometrical objects like spheres, which can then be matched, is a new and alternative solution.
Conclusions
Surface-based morphing allows functional data to be displayed while respecting the surface topology in contrast to slice representations or flat maps. The kind of graphical data representation chosen depends on the intention of visualisation. Surface-based morphing of functional and anatomical data is a new perspective for visualisation and 3D reconstruction of functional MRI data.