SAMCEP Society consensus on the treatment of upper facial lines with botulinum neurotoxin type A: A tailored approach.

BACKGROUND: The safety and efficacy of botulinum neurotoxin type A (BoNTA) treatments are well established, but injection techniques, target muscles, and toxin doses continue to evolve, with each refinement producing improvements in treatment outcomes. The recommendations in this consensus move away from standard templates and illustrate how to tailor treatments to individual patterns and strengths of muscle activity, and patient preferences. METHODS: Seventeen experts in the fields of plastic surgery, dermatology, ophthalmology, otorhinolaryngology, and neurology convened in 2022 to develop consensus-based recommendations for the use of botulinum toxin A for the treatment of horizontal forehead lines, glabellar frown lines, and crow's feet lines that reflect current clinical practice. The focus was on how to tailor injections to individual patients to optimize treatment outcomes. RESULTS: For each upper face indication, consensus members describe how to perform a dynamic assessment to optimize the dose and injection technique for each patient. A tailored treatment protocol is presented for commonly observed patterns of dynamic lines. Units of Inco are defined and the precise location of injection points, illustrated with the use of anatomical images. CONCLUSION: This consensus provides up-to-date recommendations on the tailored treatment of upper facial lines based on the latest research and collective clinical experience of the expert injectors. Optimal outcomes require thorough patient evaluation, both at rest and during animation, using both visual and tactile cues; detailed understanding of facial muscular anatomy and how opposing muscles interact; and use of a BoNTA with high precision to target identified zones of excess muscle activity.

Feasibility study of a mixed reality tool for real 3D visualization and planning of left atrial appendage occlusion.

In left atrial appendage occlusion (LAAO), pre-procedural imaging is pivotal to describe the highly variable LAA anatomy and to guide the operator in device sizing and interventional planning. Multiplanar reconstruction and 3D rendering are used for the interpretation of 3D CT datasets. However, this method of review of such imaging, which is mediated by 2D screens, may be limited due to the lack of true 3D visualization of the structures of interest; Mixed Reality (MxR) may further improve the CT-based pre-procedural planning by allowing for real-3D visualizations with holographic replicas of anatomical models. In this manuscript we present a novel software based on MxR and we evaluated its feasibility on different LAA morphologies. The morphological analysis of the holographic anatomical models was successfully applied for all the patients (n â€‹= â€‹4) independently from the morphology and it was performed in less than 10 minutes. Our findings suggest that with further developments MxR could have the potential to become a pivotal tool in LAA occlusion planning thanks to the real-3D perception, possibly leading to a more accurate and faster planning phase.

Subject-specific multiscale modeling of aortic valve biomechanics.

A Finite Element workflow for the multiscale analysis of the aortic valve biomechanics was developed and applied to three physiological anatomies with the aim of describing the aortic valve interstitial cells biomechanical milieu in physiological conditions, capturing the effect of subject-specific and leaflet-specific anatomical features from the organ down to the cell scale. A mixed approach was used to transfer organ-scale information down to the cell-scale. Displacement data from the organ model were used to impose kinematic boundary conditions to the tissue model, while stress data from the latter were used to impose loading boundary conditions to the cell level. Peak of radial leaflet strains was correlated with leaflet extent variability at the organ scale, while circumferential leaflet strains varied over a narrow range of values regardless of leaflet extent. The dependency of leaflet biomechanics on the leaflet-specific anatomy observed at the organ length-scale is reflected, and to some extent emphasized, into the results obtained at the lower length-scales. At the tissue length-scale, the peak diastolic circumferential and radial stresses computed in the fibrosa correlated with the leaflet surface area. At the cell length-scale, the difference between the strains in two main directions, and between the respective relationships with the specific leaflet anatomy, was even more evident; cell strains in the radial direction varied over a relatively wide range ([Formula: see text]) with a strong correlation with the organ length-scale radial strain ([Formula: see text]); conversely, circumferential cell strains spanned a very narrow range ([Formula: see text]) showing no correlation with the circumferential strain at the organ level ([Formula: see text]). Within the proposed simulation framework, being able to account for the actual anatomical features of the aortic valve leaflets allowed to gain insight into their effect on the structural mechanics of the leaflets at all length-scales, down to the cell scale.

Mass-spring models for the simulation of mitral valve function: Looking for a trade-off between reliability and time-efficiency.

Patient-specific finite element (FE) models can assess the impact of mitral valve (MV) repair on the complex MV anatomy and function. However, FE excessive time requirements hamper their use for surgical planning; mass-spring models (MSMs) represent a more approximate approach but can provide almost real-time simulations. On this basis, we implemented MSMs of three healthy MVs from cardiac magnetic resonance (cMR) imaging to simulate the systolic MV closure, including the in vivo papillary muscles and annular kinematics, and the anisotropic and non-linear mechanical response of MV tissues. To test MSM reliability we compared the systolic peak configurations computed by MSMs and FE: mismatches by less than twice the in-plane cMR image resolution were detected over 75% of the leaflets' surface, independently of the MSM mesh refinement and of the specific MV anatomy. Data on MSMs time-efficiency and data from the comparison of MSMs vs. FE models suggest that MSM could represent a suitable trade-off between almost real-time simulations and reliability when computing MV systolic configuration, with the potential to be used in a clinical setting either as a support to the decisional process or as a virtual training tool.

Towards the improved quantification of in vivo abnormal wall shear stresses in BAV-affected patients from 4D-flow imaging: Benchmarking and application to real data.

Bicuspid aortic valve (BAV), i.e. the fusion of two aortic valve cusps, is the most frequent congenital cardiac malformation. Its progression is often characterized by accelerated leaflet calcification and aortic wall dilation. These processes are likely enhanced by altered biomechanical stimuli, including fluid-dynamic wall shear stresses (WSS) acting on both the aortic wall and the aortic valve. Several studies have proposed the exploitation of 4D-flow magnetic resonance imaging sequences to characterize abnormal in vivo WSS in BAV-affected patients, to support prognosis and timing of intervention. However, current methods fail to quantify WSS peak values. On this basis, we developed two new methods for the improved quantification of in vivo WSS acting on the aortic wall based on 4D-flow data. We tested both methods separately and in combination on synthetic datasets obtained by two computational fluid-dynamics (CFD) models of the aorta with healthy and bicuspid aortic valve. Tests highlighted the need for data spatial resolution at least comparable to current clinical guidelines, the low sensitivity of the methods to data noise, and their capability, when used jointly, to compute more realistic peak WSS values as compared to state-of-the-art methods. The integrated application of the two methods on the real 4D-flow data from a preliminary cohort of three healthy volunteers and three BAV-affected patients confirmed these indications. In particular, quantified WSS peak values were one order of magnitude higher than those reported in previous 4D-flow studies, and much closer to those computed by highly time- and space-resolved CFD simulations.

A novel approach to the quantification of aortic root in vivo structural mechanics.

Understanding aortic root in vivo biomechanics can help in elucidating key mechanisms involved in aortic root pathologies and in the outcome of their surgical treatment. Numerical models can provide useful quantitative information. For this to be reliable, detailed aortic root anatomy should be captured. Also, since the aortic root is never unloaded throughout the cardiac cycle, the modeled geometry should be consistent with the in vivo loads acting on it. Achieving such consistency is still a challenge, which was tackled only by few numerical studies. Here we propose and describe in detail a new approach to the finite element modeling of aortic root in vivo structural mechanics. Our approach exploits the anatomical information yielded by magnetic resonance imaging by reconstructing the 3-dimensional end-diastolic geometry of the aortic root and makes the reconstructed geometry consistent with end-diastolic loading conditions through the estimation of the corresponding prestresses field. We implemented our approach through a semiautomated modeling pipeline, and we applied it to quantify aortic root biomechanics in 4 healthy participants. Computed results highlighted that including prestresses into the model allowed for pressurizing the aortic root to the end-diastolic pressure while matching the image-based ground truth data. Aortic root dynamics, tissues strains, and stresses computed at relevant time points through the cardiac cycle were consistent with a broad set of data from previous computational and in vivo studies, strongly suggesting the potential of the method. Also, results highlighted the major role played by the anatomy in driving aortic root biomechanics.

Trans-physeal anterior cruciate ligament reconstruction in adolescents.

PURPOSE: The aim of the study was to evaluate, in a group of adolescents, the onset of varus-valgus deviations in the sagittal plane after performing a trans-tibial trans-epiphyseal technique of ACL reconstruction with a follow-up of at least 2 years. METHODS: Seventy-one patients aged 12-15 years old (Tanner scale 3 and 4) have undergone ACL reconstruction with STG using arthroscopy. All patients were evaluated clinically using the visual analogue scale (VAS), the Lysholm score and the Tegner activity score at the time of surgery. All patients were reevaluated after a follow-up period of at least 2 years (T1) using the VAS, the Lysholm score, the Tegner activity score and radiographic studies in order to compare the operated limb with the healthy control limb. RESULTS: Valgus difference exceeding 2° in the knee axis between the operated limb and the healthy control limb was observed only in three patients (4.2%: 95% CI 0.88-11.86%). The average difference was <1° (0.3°, 95% CI 0.0-0.55). CONCLUSION: The trans-tibial trans-epiphyseal technique of ACL reconstruction, according to the results obtained, seems to be a valid alternative procedure, when performed by a skilled orthopaedic surgeon, offering an excellent safety profile and at the same time very good clinical results. LEVEL OF EVIDENCE: IV.

Influence of the aortic valve leaflets on the fluid-dynamics in aorta in presence of a normally functioning bicuspid valve.

In this work, we consider the blood fluid-dynamics in the ascending aorta in presence of a normally functioning bicuspid aortic valve (BAV). In particular, we perform an unsteady finite element study in real geometries with physiological velocity boundary conditions at the inlet to assess the effect of the inclusion of the leaflets on the fluid-dynamic abnormalities characterizing BAV cases. To this aim, we perform a comparison in two geometries (a dilated and a non-dilated ones) among three scenarios which are built up for each geometry: BAV without leaflets, BAV with leaflets, and tricuspid case with leaflets. For each case, we compute four indices quantifying flow asymmetry, reversal flows, helical patterns, and wall shear stresses. Our results show that the inclusion of the leaflets increases the fluid-dynamics abnormalities, especially for the non-dilated configuration, which presents a greater increment of the indices. In particular, we observe that the values of the time-averaged wall shear stress and of the systolic jet asymmetry increase by approximatively 100 and 40%, respectively, when considering the leaflets.

A novel passive left heart platform for device testing and research.

Integration of biological samples into in vitro mock loops is fundamental to simulate real device's operating conditions. We developed an in vitro platform capable of simulating the pumping function of the heart through the external pressurization of the ventricle. The system consists of a fluid-filled chamber, in which the ventricles are housed and sealed to exclude the atria from external loads. The chamber is connected to a pump that drives the motion of the ventricular walls. The aorta is connected to a systemic impedance simulator, and the left atrium to an adjustable preload. The platform reproduced physiologic hemodynamics, i.e. aortic pressures of 120/80 mmHg with 5 L/min of cardiac output, and allowed for intracardiac endoscopy. A pilot study with a left ventricular assist device (LVAD) was also performed. The LVAD was connected to the heart to investigate aortic valve functioning at different levels of support. Results were consistent with the literature, and high speed video recordings of the aortic valve allowed for the visualization of the transition between a fully opening valve and a permanently closed configuration. In conclusion, the system showed to be an effective tool for the hemodynamic assessment of devices, the simulation of surgical or transcatheter procedures and for visualization studies.

High accuracy in knee alignment and implant placement in unicompartmental medial knee replacement when using patient-specific instrumentation.

PURPOSE: The influence of patient-specific instrumentations on the accuracy of unicompartmental medial knee replacement remains unclear. The goal of this study was to examine the ability of patient-specific instrumentation to accurately reproduce postoperatively what the surgeon had planned preoperatively. METHODS: Twenty consecutive patients (20 knees) who suffered from isolated unicompartmental medial osteoarthritis of the knee and underwent medial knee replacement using newly introduced magnetic resonance imaging-based patient-specific instrumentation were assessed. This assessment recorded the following parameters: (1) the planned and the postoperative mechanical axis acquired through long-leg AP view radiographies; (2) the planned and the postoperative tibial slope acquired by means of standard AP and lateral view radiographies; and (3) the postoperative fit of the implanted components to the bone in coronal and sagittal planes. The hypothesis of the study was that there was no statistically significant difference between postoperative results and preoperatively planned values. RESULTS: The study showed that (1) the difference between the postoperative mechanical axis (mean 1.9° varus ± 1.2° SD) and the planned mechanical axis (mean 1.8° varus ± 1.2° SD) was not statistically significant; (2) the difference between the postoperative tibial slope (mean 5.2° ± 0.6° SD) and the planned tibial slope (mean 5.4° ± 0.6° SD) was statistically significant (p = 0.008); and (3) the postoperative component fit to bone in the coronal and sagittal planes was accurate in all cases; nevertheless, in one knee, all components were implanted one size smaller than preoperatively planned. Moreover, in two additional cases, one size thinner and one size thicker of the polyethylene insert were used. CONCLUSIONS: This study suggests that overall patient-specific instrumentation was highly accurate in reproducing postoperatively what the surgeon had planned preoperatively in terms of mechanical axis, tibial slope and component fit to bone. LEVEL OF EVIDENCE: IV.

Electrical conditioning of adipose-derived stem cells in a multi-chamber culture platform.

In tissue engineering, several factors play key roles in providing adequate stimuli for cells differentiation, in particular biochemical and physical stimuli, which try to mimic the physiological microenvironments. Since electrical stimuli are important in the developing heart, we have developed an easy-to-use, cost-effective cell culture platform, able to provide controlled electrical stimulation aimed at investigating the influence of the electric field in the stem cell differentiation process. This bioreactor consists of an electrical stimulator and 12 independent, petri-like culture chambers and a 3-D computational model was used to characterize the distribution and the intensity of the electric field generated in the cell culture volume. We explored the effects of monophasic and biphasic square wave pulse stimulation on a mouse adipose-derived stem cell line (m17.ASC) comparing cell viability, proliferation, protein, and gene expression. Both monophasic (8 V, 2 ms, 1 Hz) and biphasic (+4 V, 1 ms and -4 V, 1 ms; 1 Hz) stimulation were compatible with cell survival and proliferation. Biphasic stimulation induced the expression of Connexin 43, which was found to localize also at the cell membrane, which is its recognized functional mediating intercellular electrical coupling. Electrically stimulated cells showed an induced transcriptional profile more closely related to that of neonatal cadiomyocytes, particularly for biphasic stimulation. The developed platform thus allowed to set-up precise conditions to drive adult stem cells toward a myocardial phenotype solely by physical stimuli, in the absence of exogenously added expensive bioactive molecules, and can thus represent a valuable tool for translational applications for heart tissue engineering and regeneration.

Autologous collagen-induced chondrogenesis technique (ACIC) for the treatment of chondral lesions of the talus.

PURPOSE: Autologous collagen-induced chondrogenesis technique (ACIC) combines microfractures with the use of an injectable atelocollagen matrix that allows performing the whole cartilage repair treatment arthroscopically. The aim of this study was to evaluate the in vitro cytocompatibility of this biomaterial using human bone marrow mesenchymal stem cells and human chondrocytes. Moreover, the preliminary data of five patients affected by chondral lesion of the talus treated with the ACIC technique are shown. METHODS: Human bone marrow mesenchymal stem cells and human chondrocytes were seeded on solid and pre-solid atelocollagen scaffolds. Cell-scaffold constructs were cultured for 7 days and then prepared for histological analyses. Arthroscopic ACIC was performed in five patients affected by chondral lesions of the talus; they were clinically evaluated with AOFAS, VAS and Tegner score before and then after 6 months from surgery. RESULTS: In vitro results showed that both bone marrow mesenchymal stem cells and chondrocytes were able to efficiently colonize the whole construct, from the surface to the core, only when seeded on the pre-solid atelocollagen scaffold, but not on its solid form. No adverse events were observed in the patients treated with the ACIC technique; a significant improvement in VAS pain scale and in AOFAS score was found at 6 months follow up. CONCLUSION: Injectable atelocollagen can be considered a feasible scaffold for cartilage repair treatment, in particular if used in its pre-solid form. ACIC leads to good clinical results in the treatment for chondral lesions of the talus even if longer follow-up and a higher number of patients are necessary to confirm these data. LEVEL OF EVIDENCE: IV.

The role of vaginal Lactobacillus Rhamnosus (Normogin®) in preventing Bacterial Vaginosis in women with history of recurrences, undergoing surgical menopause: a prospective pilot study.

BACKGROUND: Bacterial vaginosis (BV), a poly-microbial clinical syndrome, is the most common cause of vaginal symptoms among women. The recurrence rate of BV is up to 30% after traditional antimicrobial therapy. Lactobacillus rhamnosus vaginal tablets have demonstrated to be a reliable topical effective and safe treatment to reduce the BV recurrence rate. AIM: to assess topical long-lasting (6 months) Lactobacillus rhamnosus effectiveness in decreasing recurrences in women with positive anamnesis of recurrent BV and concomitant hypo-estrogenism as consequence of surgical menopause. PATIENTS AND METHODS: A total of 22 consecutive patients affected by recurrent BV and treated for surgical menopause for benign pathology were enrolled. All women were treated with Lactobacillus rhamnosus vaginal tablets (Normogin(®)) according to the following protocol: 1 tablet/day for 6 days, than two tablets per week for 2 months and then one tablet once a week till 6 months. RESULTS: Of the 22 women enrolled only one has been lost after the first visit. A total of 21 cases were reported; 7 out of 21 had only one case of recurrence, while 2 out of 21 had two episodes of BV during the year successive to menopause. No side effects have been reported. CONCLUSIONS: Considering the low recurrence rate of BV during follow-up it seems that long-lasting treatment with vaginal tablets of Lactobacillus rhamnosus could reduce the BV recurrence also in women at high risk with positive history of pathology and undergoing surgical menopause with a safe profile. This study supports the use of vaginal Lactobacillus rhamnosus administration in high risk population without side effects.

Fabrication of 3D cell-laden hydrogel microstructures through photo-mold patterning.

Native tissues are characterized by spatially organized three-dimensional (3D) microscaled units which functionally define cells-cells and cells-extracellular matrix interactions. The ability to engineer biomimetic constructs mimicking these 3D microarchitectures is subject to the control over cell distribution and organization. In the present study we introduce a novel protocol to generate 3D cell laden hydrogel micropatterns with defined size and shape. The method, named photo-mold patterning (PMP), combines hydrogel micromolding within polydimethylsiloxane (PDMS) stamps and photopolymerization through a recently introduced biocompatible ultraviolet (UVA) activated photoinitiator (VA-086). Exploiting PDMS micromolds as geometrical constraints for two methacrylated prepolymers (polyethylene glycol diacrylate and gelatin methacrylate), micrometrically resolved structures were obtained within a 3 min exposure to a low cost and commercially available UVA LED. The PMP was validated both on a continuous cell line (human umbilical vein endothelial cells expressing green fluorescent protein, HUVEC GFP) and on primary human bone marrow stromal cells (BMSCs). HUVEC GFP and BMSCs were exposed to 1.5% w/v VA-086 and UVA light (1 W, 385 nm, distance from sample = 5 cm). Photocrosslinking conditions applied during the PMP did not negatively affect cells viability or specific metabolic activity. Quantitative analyses demonstrated the potentiality of PMP to uniformly embed viable cells within 3D microgels, creating biocompatible and favorable environments for cell proliferation and spreading during a seven days' culture. PMP can thus be considered as a promising and cost effective tool for designing spatially accurate in vitro models and, in perspective, functional constructs.

Preliminary baropodometric analysis of young soccer players while walking: geometric morphometrics and comparative evaluation.

AIM: The plantar support and its modifications are widely studied because of their bearing on posture. In particular, past studies have focused on the support modification during specific athletic tasks to highlight the eventual correlations between foot type and the most frequent sport injuries, due to intrinsic and extrinsic components that involve the structural and functional dynamics that act on the plantar vault during static and dynamic condition. These studies have been conducted by analyzing the morphological variation of the footprint during the performance. METHODS: In the present study the variation in shape of the baropodometrical footprint of young soccer players, has been analyzed using geometric morphometrics. This approach permits a quantification of the morphological variation of the subjects using Cartesian coordinates placed at specific points on the footprint outline, and to correlate them with physical variables. RESULTS: In the present study the young soccer players displayed a narrowing of the footprint due to a transversal variation on the isthmus, when compared to children of the same age who did not play soccer. These results suggest a physiological and biomechanical organization of the foot type in soccer due to the specific athletic tasks involved. CONCLUSION: As the foot type, in sport, is strictly associated to recurrent injuries, the result obtained in this study should be considered as indicative for future analysis. In fact, a clear and univocal knowledge of this phenomenon would be useful in the planning of a training protocol to reduce the incidence of sport related injuries.

In vitro hemodynamics and valve imaging in passive beating hearts.

Due to their high complexity, surgical approaches to valve repair may benefit from the use of in vitro simulators both for training and for the investigation of those measures which can lead to better clinical results. In vitro tests are intrinsically more effective when all the anatomical substructures of the valvular complexes are preserved. In this work, a mock apparatus able to house an entire explanted porcine heart and subject it to pulsatile fluid-dynamic conditions was developed, in order to enable the hemodynamic analysis of simulated surgical procedures and the imaging of the valvular structures. The mock loop's hydrodynamic design was based on an ad-hoc defined lumped-parameter model. The left ventricle of an entire swine heart was dynamically pressurized by an external computer-controlled pulse duplicator. The ascending aorta was connected to a hydraulic circuit which simulated the input impedance of the systemic circulation; a reservoir passively filled the left atrium. Accesses for endoscopic imaging were located in the apex of the left ventricle and in the aortic root. The experimental pressure and flow tracings were comparable with the typical in vivo curves; a mean flow of 3.5±0.1l pm and a mean arterial pressure of 101±2 mmHg was obtained. High-quality echographic and endoscopic video recordings demonstrated the system's excellent potential in the observation of the cardiac structures dynamics. The proposed mock loop represents a suitable in vitro system for the testing of minimally-invasive cardiovascular devices and surgical procedures for heart valve repair.

Computational modeling for the optimization of a cardiogenic 3D bioprocess of encapsulated embryonic stem cells.

We present a computational fluid dynamics (CFD)-based model aimed at the identification of optimized culture conditions promoting efficient cardiogenesis of hydrogel-bead-encapsulated embryonic stem cells (ESCs) within a rotating bioreactor. The numerical approach, integrating diffusion, convection, and multiphase fluid dynamics calculations, allowed to evaluate (i) the microgravity motion of the floating beads, (ii) the O(2) delivery to the cells, also (iii) taking into account the cellular O(2) consumption, as a function of different rotation speeds of the breeding chamber. According to our results, a 25 rpm rotation (i) enhances an adequate mixing of the cell carriers, avoiding sedimentation and excessive packing, also maintaining a quite homogeneous distribution of the suspended beads and (ii) imparts a proper cellular O(2) supply, providing cells close to a normoxia condition. The bioreactor working conditions derived from the numerical analysis allowed the attainment of in vitro long-term cell viability maintenance, supporting efficient large-scale generation of ESC-derived cardiomyocytes (ESC-DCs) through a chemical-based conditioning bioprocess. In conclusion, we demonstrated the feasibility of using CFD-based tools, as a reliable and cost-effective strategy to assist the design of a 3D cardiogenic bioprocess.

In vitro study of aortic valves treated with neo-chordae grafts: hydrodynamics and tensile force measurements.

Reparative surgery of the aortic root functional unit (ARFU) allows for a better preservation of the functionality of the native structure compared to prosthesis implantation. Post-operative results are satisfactory, whereas mid- and long-term results are challenging, for example in terms of cusps prolapse recurrence. At the Cardiothoracic Surgery Unit of the Sacco Hospital, a new surgical technique aimed at the stabilization in time of the results of standard ARFU repair operations has been applied. This technique, inspired by the mitral neo-chordae (NC) implantation, consists of implanting an e-PTFE suture thread between the prolapsed cusp and the sinotubular junction. Aim of this study was to assess the influence of NC implantation on the ARFU functioning by evaluating with an owned pulsatile in vitro apparatus the force magnitude acting on the NC and the dynamic behavior of porcine ARFUs treated according to the operating-room procedures. The maximum recorded values of the mean and peak diastolic forces were 0.064 and 0.186 N, respectively, and were linearly dependent upon the mean diastolic pressure across the valve. In addition, the measurements of the opening-closing times and valve leakage volumes, performed at pre- and post-surgeries, yielded that the valve functionality was not significantly influenced by NC implantation.

Left ventricular modelling: a quantitative functional assessment tool based on cardiac magnetic resonance imaging.

We present the development and testing of a semi-automated tool to support the diagnosis of left ventricle (LV) dysfunctions from cardiac magnetic resonance (CMR). CMR short-axis images of the LVs were obtained in 15 patients and processed to detect endocardial and epicardial contours and compute volume, mass and regional wall motion (WM). Results were compared with those obtained from manual tracing by an expert cardiologist. Nearest neighbour tracking and finite-element theory were merged to calculate local myocardial strains and torsion. The method was tested on a virtual phantom, on a healthy LV and on two ischaemic LVs with different severity of the pathology. Automated analysis of CMR data was feasible in 13/15 patients: computed LV volumes and wall mass correlated well with manually extracted data. The detection of regional WM abnormalities showed good sensitivity (77.8%), specificity (85.1%) and accuracy (82%). On the virtual phantom, computed local strains differed by less than 14 per cent from the results of commercial finite-element solver. Strain calculation on the healthy LV showed uniform and synchronized circumferential strains, with peak shortening of about 20 per cent at end systole, progressively higher systolic wall thickening going from base to apex, and a 10° torsion. In the two pathological LVs, synchronicity and homogeneity were partially lost, anomalies being more evident for the more severely injured LV. Moreover, LV torsion was dramatically reduced. Preliminary testing confirmed the validity of our approach, which allowed for the fast analysis of LV function, even though future improvements are possible.

Visualization and simulated surgery of the left ventricle in the virtual pathological heart of the Virtual Physiological Human.

Ischaemic heart failure remains a significant health and economic problem worldwide. This paper presents a user-friendly software system that will form a part of the virtual pathological heart of the Virtual Physiological Human (VPH2) project, currently being developed under the European Commission Virtual Physiological Human (VPH) programme. VPH2 is an integrated medicine project, which will create a suite of modelling, simulation and visualization tools for patient-specific prediction and planning in cases of post-ischaemic left ventricular dysfunction. The work presented here describes a three-dimensional interactive visualization for simulating left ventricle restoration surgery, comprising the operations of cutting, stitching and patching, and for simulating the elastic deformation of the ventricle to its post-operative shape. This will supply the quantitative measurements required for the post-operative prediction tools being developed in parallel in the same project.