Advancing the characterization of neuronal cyto architecture by x ray phase contrast tomography To bring physiology and pathology of the human brain into better micro anatomical and histological context studies with different methodologies are required. Established techniques such as electron microscopy or histology show limitations in view of invasiveness labor intense and artifact prone sample preparation as well as an adequate ratio between resolution and volume throughput. For this reason X ray phase contrast tomography (PC CT) has been proposed as a three dimensional non destructive imaging technique which requires less effort in sample preparation and can assess larger volumes. Furthermore it offers quantitative electron density based contrast even for unstained tissue. Up to now however PC CT studies fell short in number of samples so that structural alterations caused by neurodegenerative diseases cannot be distinguished from physiological inter subject variations. In this thesis the scalability of PC CT with respect to the required number of samples and resolution to volume throughput is demonstrated and the methodology is advanced with respect to data acquisition processing and segmentation. In addition to the human cerebellum cortex and hippocampus are studied. Concerning quantification and analysis of PC CT data this work introduces optimal transport analysis to obtain quantitative metrics of the cyto architecture and to identify changes due to neurodegenerative diseases. For the case of Alzheimer’s disease this workflow reveals a yet undescribed compactification of granular cells in the human hippocampus. This thesis also provides optimized configurations to study neural tissues with laboratory instrumentation and – finally – provides new correlative imaging approaches in particular with scanning electron microscopy.