Background: Registration is a key process in comparing different image sets. The registered images are used by surgeons for reasons of evaluation and surveillance (e.g.post-operative position control and particular health state evaluation). To compare images at an appropriate level of quality, it requires an understanding of how the images are related to each other and which registration basis and transformation should be chosen, to achieve the best possible registration result. The intention of this thesis is, to develop and evaluate a registration method for comparing the amount of cerebrospinal fluid, in order to apply it as a basis for the deep brain stimulation. Since the cerebrospinal fluid has an influence on the electrical current within the brain it is important, to know how much cerebrospinal fluid exists.

Material and Methods: This thesis presents a straightforward approach, to register magnetic resonance (MR) image sets by subtracting the normalized intensities and by calculating the particular rigid transformations. Two T2 weighted image sets and two spoiled gradient recalled echo (SPGR) image sets were used for the registration process. Furthermore the T2 images were used for the validation of the whole registration method.

Results: Both image set modalities, the T2 as well as the SPGR were successfully registered using the developed registration method. Therefore a translation correction of 54pixels in x-direction, respectively 65 pixels in y-direction (T2) and 7 pixels in x-direction, respectively 6 pixels in y-direction (SPGR) was necessary. The detected rotation of 1.5 °in the T2 matching set was adjusted too. The SPGR matching set showed no rotation. The median sum of squares of intensity differences resulted in a value of 6438 (T2) and25.86 (SPGR). The validation procedure constitutes an indication that the developed registration process is reliable and stable.

Conclusion: The implemented registration procedure constitutes a straightforward, timeconsuming approach, which is useful to gain results within the same image modality. If there is any need for an inter-modality registration, the approach must be changed.