Trabecular bone score (TBS) the new parameter of 2D texture analysis for the evaluation of 3D bone micro architecture status

X-ray is a technology that is used for numerous applications in the medical field. The process of X-ray projection gives a 2-dimension (2D) grey-level texture from a 3- dimension (3D) object. Until now no clear demonstration or correlation has positioned the 2D texture analysis as a valid indirect evaluation of the 3D microarchitecture. TBS is a new texture parameter based on the measure of the experimental variogram. TBS evaluates the variation between 2D image grey-levels. The aim of this study was to evaluate existing correlations between 3D bone microarchitecture parameters - evaluated from μCT reconstructions - and the TBS value, calculated on 2D projected images. 30 dried human cadaveric vertebrae were acquired on a micro-scanner (eXplorer Locus, GE) at isotropic resolution of 93 μm. 3D vertebral body models were used. The following 3D microarchitecture parameters were used: Bone volume fraction (BV/TV), Trabecular thickness (TbTh), trabecular space (TbSp), trabecular number (TbN) and connectivity density (ConnD). 3D/2D projections has been done by taking into account the Beer-Lambert Law at X-ray energy of 50, 100, 150 KeV. TBS was assessed on 2D projected images. Correlations between TBS and the 3D microarchitecture parameters were evaluated using a linear regression analysis. Paired T-test is used to assess the X-ray energy effects on TBS. Multiple linear regressions (backward) were used to evaluate relationships between TBS and 3D microarchitecture parameters using a bootstrap process. BV/TV of the sample ranged from 18.5 to 37.6% with an average value at 28.8%. Correlations' analysis showedthat TBSwere strongly correlatedwith ConnD(0.856≤r≤0.862; p<0.001),with TbN (0.805≤r≤0.810; p<0.001) and negatively with TbSp (−0.714≤r≤−0.726; p<0.001), regardless X-ray energy. Results show that lower TBS values are related to "degraded" microarchitecture, with low ConnD, low TbN and a high TbSp. The opposite is also true. X-ray energy has no effect onTBS neither on the correlations betweenTBS and the 3Dmicroarchitecture parameters. In this study, we demonstrated that TBS was significantly correlated with 3D microarchitecture parameters ConnD and TbN, and negatively with TbSp, no matter what X-ray energy has been used. This article is part of a Special Issue entitled ECTS 2011. Disclosure of interest: None declared.

How to Measure Scope Variables when no Metrics Exist : Application to Landscape Quality Measurement and Hedonic Price Evaluation

Landscape is an example of a non-market good where no metrics exist to measure its quality. The paper proposes an original methodology to nevertheless estimate scope variables in those circumstances, allowing then to better test if people's willingnesstopay for such good is sensitive to the scope. The methodology is based on techniques developed in the context of multicriteria decision analysis. It is applied to assess the quality of the landscape of several Swiss alpine resorts. This assessment is then used as an explanatory variable in a hedonic price function to explain the rent of apartments and to derive an implicit price of the landscape quality.

Mapping complex tissue architecture with diffusion spectrum magnetic resonance imaging.

Methods are presented to map complex fiber architectures in tissues by imaging the 3D spectra of tissue water diffusion with MR. First, theoretical considerations show why and under what conditions diffusion contrast is positive. Using this result, spin displacement spectra that are conventionally phase-encoded can be accurately reconstructed by a Fourier transform of the measured signal's modulus. Second, studies of in vitro and in vivo samples demonstrate correspondence between the orientational maxima of the diffusion spectrum and those of the fiber orientation density at each location. In specimens with complex muscular tissue, such as the tongue, diffusion spectrum images show characteristic local heterogeneities of fiber architectures, including angular dispersion and intersection. Cerebral diffusion spectra acquired in normal human subjects resolve known white matter tracts and tract intersections. Finally, the relation between the presented model-free imaging technique and other available diffusion MRI schemes is discussed.

Al di là del fiume - attraverso il fiume: il basso corso del Ter in Catalogna

La ricerca prende in considerazione dal punto di vista dell’architettura e dell’urbanistica la relazione tra la città e il fiume che la attraversa o la lambisce; l’insediamento umano viene analizzato nel contesto del bacino idrografico al quale appartiene. La ricerca è stata sviluppata in seno alla tesi dottorale ora in fase di elaborazione presso il Departamento de Urbanismo y Ordenación del Territorio dell’Universidad Politecnica de Catalunya. La tesi ha come caso studio il tratto basso del fiume Ter in Catalogna. Nella discussione sul paesaggio urbano contemporaneo oggi la riflessione è centrata sulla città che si territorializza; la dimensione urbana interferisce con gran parte della superficie della terra facendo sfumare le tradizionali distinzioni tra urbano e non-urbano, tra spazio costruito e spazio aperto. In questo contesto, quale termine di conciliazione tra la dinamica naturale e la costruzione storica dei luoghi prodotta dall’intervento umano, il fiume si rivela uno strumento essenziale di analisi e progetto. L’obiettivo di questa ricerca è suggerire un’approssimazione al progetto della città che si sviluppa lungo il corso fluviale costruendo strumenti per la riflessione “attraverso il fiume”. Partendo dall’ipotesi che la città si insedia lungo un corso d’acqua secondo una sintassi territoriale stabilita dalla geografía e dalla geomorfologia del fiume stesso, il fine è fornire strumenti per il processo di recupero degli spazi fluviali in contesti urbanizzati. Il fiume diviene componente geografica chiave degli insediamenti dispersi e risorsa per costruirne l’abitabilità.

Enterprise Architecture Management Design: Towards Understanding Organizational Contingencies, Design Principles and Effectiveness

Despite the increasing popularity of enterprise architecture management (EAM) in practice, many EAM initiatives either do not fully meet the expected targets or fail. Several frameworks have been suggested as guidelines to EA implementation, but companies seldom follow prescriptive frameworks. Instead, they follow very diverse implementation approaches that depend on their organizational contingencies and the way of adopting and evolving EAM over time. This research strives for a broader understanding of EAM by exploring context-dependent EAM adoption approaches as well as identifying the main EA principles that affect EA effectiveness. Based on two studies, this dissertation aims to address two main questions: (1) EAM design: Which approaches do companies follow when adopting EAM? (2) EA principles and their impact: What impact does EA principles have on EA effectiveness/quality? By utilizing both qualitative and quantitative research methods, this research contributes to exploring different EAM designs in different organizational contingencies as well as using EA principles as an effective means to achieve principle-based EAM design. My research can help companies identify a suitable EAM design that fits their organizational settings and shape their EA through a set of principles.