MR-guided focused ultrasound ablation targets small thalamic nuclei that are frequently difficult to distinguish from surrounding tissue. The ability to accurately evaluate the success in ablating the target nuclei is essential for predicting treatment outcome and evaluating surgical performance. We show microstructural changes in the thalamus that may prevent accurate post-surgical tractography. We propose a straightforward technique that reconstructs neuronal connections in the pre-surgical brain using the post-operative lesioned area as a seed-region for constrained spherical deconvolution based tractography. The proportion of tracts leading to regions known to be connected to the target nuclei is then evaluated.