Magnetic resonance techniques for the brainstem.

Imaging of the brainstem is a real challenge from the technical point of view, because it is a very complex structure. There are gray matter nuclei with vital functions mixed to white matter tracts with very important connections, as the Cortico-Spinal Tract (CST). On the other hand, the situation of the brainstem, near bony structures and surrounded by vessels adds even more difficulties due to the lower homogeneity of the field and the flow effect of both the vessels and the CSF. Structural imaging with 3-D sequences, either in T1 or T2 has been a major advance in the diagnosis of small lesions of the brainstem. Advanced techniques such as Spectroscopy, Diffusion and Perfusion sequences add important information that can reliably handle many lesions in which biopsy is a very high risk. Therefore, proper management of imaging techniques is particularly important in lesions of the brainstem.