Quantitative Analysis of White Matter Fiber Properties along Geodesic Paths

Diffusion Tensor Imaging (DTI) is becoming a routine magnetic resonance technique to study white matter properties and alterations of fiber integrity due to pathology. The advanced MRI technique needs postprocessing by adequate image processing and visualization tools. Analysis of DTI in clinical studies so far use manual definition of regions or interest or image matching followed by voxel-based analysis. This paper presents a novel concept that extracts major fiber bundles by tractography and provides a statistical analysis of diffusion properties along fibers, i.e. geodesic paths within the three-dimensional brain image. Fiber tracing thus serves as a sophisticated, efficient method for defining complex regions of interests along major fiber tracts not accessible otherwise. Fiber bundles extracted from a set of subjects are parametrized by arc-length and mapped to a common coordinate system centered at well-defined anatomical landmarks. The description of the methodology is guided by the example of measuring diffusion properties along the left and right cingulate. We also present preliminary results from an ongoing clinical neonatal study that studies early brain development.