High-Resolution Mapping of the Human Olfactory Bulb Using X-Ray Phase Contrast Tomography and Virtual Surface Unfolding

The human olfactory bulb (OB) is a complex neural structure critical for odor processing and one of the earliest sites of pathology in a number of neurodegenerative diseases. We used X–ray phase contrast tomography (XPCT) to obtain high–quality 3D images of OB tissue from postmortem patients, allowing detailed visualization of soft tissue microarchitecture, including the olfactory glomeruli. To improve spatial analysis, we developed a computational unfolding method that transforms the curved surface of the OB into a 2D map. This transformation preserves anatomical relationships, allowing accurate quantification of glomeruli by number, size, shape, and distribution. The unfolded representations of OB image support in–depth statistical analysis and are compatible with machine learning tools for automated detection and classification of OB morphological structures. This method provides a powerful framework for studying olfactory function and identifying early structural changes in diseases such as Parkinson's disease, Alzheimer's disease, and COVID–19–associated anosmia. By integrating XPCT with virtual unfolding, we offer a new approach to mapping OB morphological features with increased clarity and diagnostic accuracy.