Real-Time US-CT fusion imaging for guidance of thermal ablation in of renal tumors invisible or poorly visible with US: results in 97 cases

Purpose To assess the capability of ultrasound-computed tomography (US-CT) fusion imaging to guide a precise targeting of renal tumors invisible or poorly visible with US Materials and methods From 2016 renal tumors poorly visible or inconspicuous/invisible at US were treated at our institution with the guidance of US/CT fusion in a room equipped with CT scanner. Feasibility of the procedure, accuracy of targeting, complications, and technique efficacy were evaluated. Results Of 227 patients treated from 2016 to March 2020, 91 patients (65 males and 26 females, mean age 68.5 ± 10.1 years) with 97 renal lesions (mean maximum diameter 21.6 ± 9.4 mm) inconspicuous/invisible (29/97, 29.9%) or poorly visible (68/97, 70.1%) at US underwent treatment under US-CT fusion guidance. US-CT fusion imaging guidance was always technically feasible and enabled correct targeting in 97/97/(100%) of cases. Technical success was achieved in 93/97 lesions (95.9%). Three lesions were retreated during the same ablative session, while 1 was retreated in a subsequent session. Thus, primary efficacy was achieved in one session in 96/97 (98.9%) cases and secondary efficacy in 97/97 (100%) cases Conclusion US-CT image fusion guidance allows for a correct tumor targeting of renal tumors poorly visible or inconspicuous/invisible with US alone, with a high rate of technical success and technique efficacy

Health-related quality of life in patients with primary open-angle glaucoma. An Italian multicentre observational study

Purpose: As a progressive condition, glaucoma may impair health-related quality of life (HRQoL), due to vision loss and other factors. This study evaluated HRQoL in a cohort of patients treated for primary open-angle glaucoma (POAG) and assessed its association with clinical features. Methods: This was an Italian, multicentre, cross-sectional, observational study with the subgroup of newly diagnosed patients with POAG prospectively followed up for one year. Patients with previous or new diagnosis (or strong clinical suspicion) of POAG aged >18 years were considered eligible. Information was collected on demographic characteristics, medical history, clinical presentation and POAG treatments. HRQoL was measured using the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) and Glaucoma Symptom Scale (GSS). Subscale and total scores were obtained and a Pearson correlation coefficient between instruments’ scores calculated. Results: A total of 3227 patients were enrolled from 2012 to 2013 and 3169 were analysed. Mean age was 66.9 years. A total of 93.8% had a previous diagnosis (median duration: 8.0 years). Median values for mean deviation and pattern standard deviation were 3.9 and 3.6 dB, respectively. Mean scores on most subscales of the NEI-VFQ-25 exceeded 75.0 and mean GSS subscale scores ranged between 70.8 and 79.7 (with a total mean score of 74.8). HRQoL scores on both scales were significantly inversely associated with POAG severity. Conclusion: In this large sample of Italians treated for POAG, disease severity was limited and HRQoL scores were high. QoL decreased with advancing disease severity. These findings confirm the role of vision loss in impairing QoL in POAG, underlying the importance of timely detection and appropriate treatment

Modelli continui 1D di sistemi di blocchi in forma di archi e piattabande

Si consideri un sistema costituito da blocchi collegati da giunti di spessore sottile, disposti in modo da costituire un ‘arco’ o una ‘piattabanda’ di altezza e larghezza costanti. I solidi ‘arco’ e ‘piattabanda’ abbiano un asse costituto da una curva regolare piana, e da un segmento di retta, rispettivamente. I giunti siano disposti con regolarità in modo da determinare una variazione regolare della forma dei blocchi. In una prima fase di modellazione si assume che i blocchi siano corpi rigidi e i giunti interfacce elastiche.Successivamente si introduce un modello di trave monodimensionale con sezioni rigide per descrivere sommariamente il comportamento meccanico dei sistemi a blocchi. Si considera innanzitutto una configurazione iniziale in cui l’asse della trave coincide con l’asse del solido ‘arco’ o ‘piattabanda’ e le sezioni sono disposte lungo questo seguendo l’assetto dei giunti. Nel caso dell’arco, le sezioni sono ortogonali alla linea d’asse mentre nel caso della piattabanda formano un angolo variabile con continuità. Il caso più generale è quello in cui l’asse è una linea curva e le sezioni non sono ad esso ortogonali. Postulando una relazione di equivalenza in potenza tra i processi dinamici del modello discreto e quelli della trave, per atti di moto test corrispondenti, si esprimono le azioni di contatto della trave in funzione di quelle nel discreto ( vedi Masiani et al. 1995 ). Assegnata quindi una relazione costitutiva per le azioni di contatto del modello discreto, si ricava la relazione corrispondente per la azioni interne della trave.Tramite la relazione costitutiva il modello continuo, pur se sommario, si rivela capace di tenere in conto aspetti legati alla disomogeneità del materiale e alla geometria dei blocchi

The effects of warping on the postbuckling behaviour of thin-walled structures

A direct 1D model able to describe the mechanical behaviour of thin-walled beams is used to analyse the initial postbuckling of some sample frames. The model allows to take into account the boundary conditions on warping in a very simple way and proves to be a very efficient tool for the analysis of thin-walled frames. Making use of the FEM based COMSOL multiphysics software, numerical results for a number of L frames are obtained and shown

On the Postbuckling Analysis of Thin-Walled Frames

Using a direct one dimensional beam model with an internal structure including a kinematical descriptor which accounts for gross warping, the analysis of an L frame made up of thin walled beams is performed up to the initial postbuckling range. The beams have cross sections with only one axis of symmetry but the frame is symmetric and symmetrically loaded. Numerical results have been obtained by means of the finite element method using the COMSOL Multiphysics software. The results show that, despite the geometric and dynamic symmetry of the frame and depending on the transmission of warping between the beams, the frame can be imperfection sensitive

On the Postbuckling Behaviour of Thin Walled Beams with In-Plane Deformable Cross-Sections

"In this paper a procedure for obtaining a beam model from a thin plate theory, is introduced. The starting point is the theory proposed by Koiter which describes the deformation of the plate in a kinematically exact way. By assuming some fair constraints on the plate motion, its deformation measures can be described by means of four scalar parameters that are a measure of the elongation, two bending terms and the torsion of a 1D continuum. Given that the plate is thin and made up of a material that is isotropic elastic and linear in the 2D finite strains, its strain energy is written in terms of the 1D strains. The resulting function is then given a power expansion. Taking the derivative of this expression with respect to the 1D strain measures, the constitutive functions of the corresponding stress measures are obtained. Some samples show how the procedure can be used to study the mechanical behaviour of TWBs with open cross sections.

A 1D nonlinear TWB model derived from an assembly of Koiter Shells

In this work, TWBs with open cross sections are considered. At first they are viewed as an assembly of plates each one of them being a wall of the TWB. Each plate is then modeled as a Koiter shell, initially flat. This allows for using the two fundamental forms of the middle surface of the shell as strain measures. On the middle surface of each plate two local coordinates are introduced: we will call them longitudinal and transversal, respectively. It is assumed that the components of the displacement field which characterize the middle surface kinematics can be expressed as a product of two functions: one defined along the longitudinal coordinate and one defined along the transversal coordinate. Given an explicit expression of the latter functions the 2D plate fields are reduced to 1D ones. The functions of the transversal coordinate are chosen so that the stretch along it together with the membrane shear, vanish. It is worth noting that the linearization of these constraints leads to the well known Vlasov’s assumptions. The walls are assembled by imposing suitable boundary conditions on their longitudinal edges. This procedure gives rise to an hyperelastic 1D beam model in which at least the warping is taken into account. The main features of the model are shown by means of some simple application