• risonanza magnetica
• sostanza bianca
• trattografia
• tronco encefalico

Background: Diffusion tensor imaging (DTI)-based tractography of the brainstem is a useful presurgical planning tool for resection of focal lesions of the brainstem, due to the tight crowding of gray matter nuclei, and white matter pathways in a narrow space. Previous DTI-based atlases of brainstem connections identified a few major tracts, with limited spatial resolution.
Objective: To create high-resolution, wide-population based, comprehensive atlas of the single white matter tracts of the brainstem, and present a tractography-based review of the traditional approaches to the brainstem.
Methods: We applied advanced deterministic fiber tractography to a template of 488 subjects from the Human Connectome Project (HCP-488). Five formalin fixed brains were studied for surgical landmarks. Then, Luxol Fast Blue stained histological sections were used to validate the results of tractography.
Results: The tractographic anatomy of single white matter tracts is described, including: the cerebellar peduncles, the corticospinal tract (CST), the corticopontine tracts (CPTs), the medial lemniscus (ML), the lateral lemniscus (LL), the spinothalamic tract (STT), the rubrospinal tract (RST), the central tegmental tract (CTT), the medial longitudinal fasciculus (MLF), the dorsal longitudinal fasciculus (DLF). Then, the reconstructed 3-dimensional brainstem model was sectioned at the level of classical surgical approaches, namely: the supracollicular approach, the infraclollucular approach, the lateral mesencephalic sulcus approach, the perioculomotor approach, the supracollicular approach, the infracollicular approach, the paratrigeminal approach, the antrolateral approach to the medulla, the retro-oivary sulcus approach. The tractographic sections were successfully validated by comparison with histological sections. Finally, the practical application of our advanced tractography method is presented in two clinical cases.
Conclusion: The study demonstrates the successful use of advanced deterministic fiber tractography as a tool for improving the knowledge of basic neuroanatomy of the brainstem, for a better understanding of traditional surgical approaches, and for presurgical planning of focal lesion resections.