Structural analysis of micro-channels in human temporal bone

Abstract

Recently, numerous micro-channels have been discovered in the human temporal bone by micro-CT-scanning. Preliminary structure of these channels has suggested they contain a new separate blood supply for the mucosa of the mastoid air cells, which may have important functional implications. This paper proposes a structural analysis of the microchannels to corroborate this role. A local structure tensor is first estimated. The eigenvalues obtained from the estimated local structure tensor were then used to build probability maps representing planar, tubular, and isotropic tensor types. Each tensor type was assigned a respective RGB color and the full structure tensor was rendered along with the original data. Such structural analysis provides new and relevant information about the micro-channels but also their connections to mastoid air cells. Before carrying a future statistical analysis, a more accurate representation of the micro-channels in terms of local structure tensor analysis using adaptive filtering is needed.

Enhancement of micro-channels within the human mastoid bone based on local structure tensor analysis

“…3. The probability of each neighbourhood belonging to either a rank 1, rank 2, or a rank 3 tensor, as defined in [5] and recalled from [3], can further be investigated from the local structure tensor by p1, p2, and p3, where…”

“…4(B). As stated in [3], to obtain rank 1, rank 2 and rank 3 tensors, a set of quadrature filter responses were computed over the whole volume so as to estimate the structure tensor given in Eq. 3.…”

“…5(B). When carefully observing the results from the previous study [3], the very thin microchannels are not fully represented along their path. The noise further corrupts their definition.…”

“…2 where the micro-channels are observed within the white ellipsoid at the vicinity of the ear canal (EC). In order to gain further knowledge about these micro-channels, a geometrical analysis has been carried out using a micro-CT scan of a single human temporal bone specimen [3]. The extraction of tubular and planar structures and combinations thereof, using local structure tensor analysis ( [5]), revealed microchannels of different size and shape.…”

“…Furthermore, presence of noise in the data prevents a clear visualisation of the micro-channels path within the bone and their linking to adjacent air cells. This study therefore proposes an extension of the local structure tensor analysis ( [3]), by enhancing the micro-CT data, while reducing the noise level using adaptive filtering [6]. Fig.…”