The reconstruction of the corticospinal tract in the human brain is a clinically important task for both surgical planning and population studies. Diffusion MRI tractography provides an in-vivo and patient-specific technique for mapping the tract’s geometry; however, crossing fibers present a challenge for the standard tensor model. In this paper, we explore the use multi-fiber models that have been shown to overcome some of these issues, and we apply methods for potentially improving on previous work with model-based processing. We conduct experiments with three real clinical dataset including normal and tumor-infiltrated corticospinal tracts and the arcuate fasciculus. We show our results with visualizations of the fiber bundles alongside volumetric data and tumor surface models. We found the multi-fiber reconstructions included lateral projections of the corticospinal tract in most cases and frontal projections of the arcuate fasciculus in one case. Our results suggest this approach could be considered for clinical applications of corticospinal tract modeling.