**9. Acknowledgment**

168 Neuroimaging for Clinicians – Combining Research and Practice

option of *in vivo* applications for clinical purposes and basic science research with quite comfortable accessibility. Volumetric and multi-sequence acquisitions of MRI images supply different sets of data, for instance, macroscopic anatomy, differentiation of gray and white matter, detection of iron deposits, fiber tracking, spectroscopy, BOLD effect in addition to the possibility of re-slicing and generating 3D reconstructions of the brain. It is even possible to differentiate the cortical layers in MRI (Fatterpekar et al., 2002). However, the protocol used to achieve this definition was a 9.4 T machine and each specimen was submitted to an overnight acquisition time of 14 hours and 17 minutes. This is not possible in living patients, not only because of the long acquisition time, but also due to movement artifacts including breathing. The subthalamic nucleus is a good example for this discussion, because it is an important target to place electrodes in Deep Brain Stimulation (DBS) for treatment of Parkinson's disease, (Limousin et al., 1995; Benabid et al., 2001; Hamani et al*.*, 2004) dystonia and epilepsy, and obsessive-compulsive disorders (Mallet et al., 2002).The real limits of STh within the hypointense image in the region lateral to the red nucleus is still matter of debate (Littlechild et al., 2003; Pollo et al., 2003; Dormont et al., 2004 ;Andrade-Souza et al., 2005 ; Sather & Patil, 2007; Stancanello et al., 2008; Kitajima et al., 2008;Caire et al., 2009; Vertinsky et al., 2009).The problem seems bigger if we consider that most neurosurgery services use 1.5 to 3.0 T magnetic fields in MRI acquisition. Although MRI images have improved in recent years, no sharp limits are really observed. Additionally, the iron content of the nucleus is unevenly distributed, predominating in its anterior aspects. We cannot forget as well the artifacts such as partial volume effect that distort the images and blur the nuclear outlines when we target small volumes (Ballester et al., 2002). On the other hand, the pioneer experiences of the first atlases based in brain histology have recently obtained substantial improvement with the addition of new staining techniques, imunohistochemestry specific to different subcellular and membrane structures of neurons and glial cells, and the development of softwares and algorithms to warp and correct the errors induced by tissue processing, all of which have made it more reliable and precise. Functional neurosurgery is aimed at functional targets, but these functional units are linked to an anatomical substrate. If we can in the future overlap the cytoarchitecture, intraoperative electrophysiology, and high-resolution functional images, we will surely be able to better understand the function and structure relationship and propose new

treatments for diseases that have seemed hopeless until now .

The future directions of image-guided neurosurgery include coherent 3D histological and histochemical volumes which can be interactively visualized and precisely warped to a given MRI scan. Templates and 3D reconstructions should be in electronic format and available over the internet , with a user-friendly interface that allows neurosurgical planning and better

The field of neurosurgery-driven brain localization is still open and growing. Technological progress will greatly improve the precision of brain targeting. Atlases are an important part of this process, and together with the developing brain imaging methods and electrophysiology,

understanding of complex brain structures and spatial and functional relationships.

future works will open new frontiers to the knowledge of the human brain as a whole.

**7. Future perspectives** 

**8. Conclusion** 

The authors would like to thank all the members of the team participating on the São Paulo-Würzburg collaborative project and their representatives: Dr. Lea T. Grinberg, Dr.Wilson Jacob Filho, Prof. Dr. Manoel Jacobsen Teixeira, Prof. Dr. Edson Amaro Jr, and Prof. Dr. Carlos Augusto Pascualucci.

The author, Eduardo Joaquim Lopes Alho, has a scholarship for doctoral studies in the Julius-Maximilian Universität Würzburg, supported by the Brazilian agency CAPES in cooperation with the German agency DAAD .

Special thanks also to Bruna Barbosa Teodoro Felix, and to David Rochester for reviewing the chapter.
