Mapping the Spatial Evolution of Proximal Femur Osteoporosis: A Retrospective Cross-Sectional Study Based on CT Scans.

Purpose: The purpose of this study was to quantify the modifications occurring in osteoporosis at the level of the human proximal femur throughout the trabecular structure, along with the identification of certain anatomic regions preferentially affected by osteoporosis. Another goal was to map the evolution of the radiodensity of the trabecular bone as osteoporosis progresses to an advanced stage. Methods: The study included CT scans (right femur) from 51 patients, out of which 40 had various degrees of osteoporosis, but no other local pathology. Ten regions of interest in two orthogonal slices have been identified and the differences in radiodensity as well as their evolution have been statistically analyzed in terms of relative and absolute changes. Results: A detailed spatial map showing the evolution of osteoporosis was obtained. As osteoporosis evolved, the relative decrease in radiodensity was inversely correlated to the radiodensity of the healthy bone. In particular, the region covering the Ward triangle decreased the most, by an average 61-62% in osteopenia and 101-106% in advanced osteoporosis, while the principal compressive group was affected the least, showing a decrease by an average 14-15% in osteopenia and 29-32% in advanced osteoporosis. The absolute decrease in radiodensity was not correlated to the radiodensity of the healthy bone and was shifted to the inferior-posterior edge of the femur. Inside the femoral head, the upper region was affected the most in absolute terms, while the greater trochanter was less affected than the femoral neck. The maximum metaphyseal cortical bone density was unaffected by the progression of osteoporosis. Conclusion: Significant differences were noticed in terms of the absolute and relative osteoporotic changes in radiodensity related to different anatomical regions of the human femoral bone. These differences become more pronounced as the disease progresses.

Correlations between Endoscopic and Histopathological Assessment of Helicobacter pylori-Induced Gastric Pathology-A Cross-Sectional Retrospective Study.

Helicobacter pylori (H. pylori) infects about half of the world's population and can lead to premalignant lesions and gastric cancer. Updated data about the correlation of histopathological diagnostics with endoscopic diagnostics are scarce. The objective of this study was to identify the concordance between endoscopic and histopathologic findings, with a focus on premalignant lesions. We performed a cross sectional, retrospective study over a 4-year period (2017−2021) on adult patients with dyspeptic symptoms and positive RUT (rapid urease test) in a single hospital centre, with a total of 133 patients infected with H. pylori being included in the study. Statistical associations between endoscopic appearance and histopathological results were found for atrophic antral gastritis (p = 0.001), intestinal metaplasia of the antrum (p = 0.018), gastric polyps (p < 0.001) and gastric corpus cancer (p = 0.012). Females were more likely to be diagnosed through endoscopy with gastric atrophy or intestinal metaplasia (p = 0.031), while chronic atrophic gastritis in corpus was more prevalent in patients older than 65 (p = 0.024). Overall, our study reveals only 21% concordance between Giemsa stain and RUT, highlighting the importance of combining rapid testing with endoscopic and histopathological diagnostic methods for a more accurate early diagnosis and prevention of gastric cancer.

Quantum Criticality and Formation of a Singular Fermi Liquid in the Attractive SU(N>2) Anderson Model.

While much is known about repulsive quantum impurity models, significantly less attention has been devoted to their attractive counterparts. This motivated us to study the attractive SU(N) Anderson impurity model. While for the repulsive case the phase diagram features mild N dependence and the ground state is always a Fermi liquid, in the attractive case a Kosterlitz-Thouless charge localization phase transition is revealed for N>2. Beyond a critical value of attractive interaction, an abrupt jump appears in the number of particles at the impurity site, and a singular Fermi liquid state emerges, where the scattering of quasiparticles is found to exhibit power law behavior with fractional power. The capacity diverges exponentially at the quantum critical point, signaling the Kosterlitz-Thouless transition.

PET-based quantification of statistical properties of hypoxic tumor subvolumes in head and neck cancer.

PURPOSE: PET hypoxia imaging of head and neck cancer (HNC) has the potential to stratify the response to radiochemotherapy. The aim of this work was to quantify the statistical properties of hypoxic tumor subvolumes measured by PET, and their impact on failure rate of standard chemoradiation. METHODS: A PubMed search was undertaken to identify relevant publications between 2001 and July 2015, containing original data regarding the properties of HNC hypoxic subvolumes and their evolution during therapy, measured using specific PET tracers. RESULTS: The number and intensity of hypoxic voxels is significantly reduced during therapy. Patients are 4.2 times more likely to have negative outcome if baseline hypoxic. The change of the hypoxic volume during therapy, as well as the statistical distribution of the hypoxic fraction (HF), is quantified and analyzed. HF strongly correlates with the median T/M (tumor-to-muscle) SUV (standard uptake value) ratio, but not with gross tumor volume. Hypoxia is 2.2 times more frequently manifest in T3 + T4 than in T1 + T2 primary tumors. Calculated quantities are presented for primary and nodal tumors separately, where available. CONCLUSIONS: Although hypoxia diminishes during chemoradiation, it is a major predictor of outcome. HF, if large enough, can be predicted from the median T/M SUV ratio. CT-delineated gross tumor size does not influence the percentage of hypoxic voxels. Primary tumors are less likely hypoxic at an earlier stage.