Partial Occlusion Research Articles

Amodal Completion: Mental Imagery or 3D Modeling?

AbstractIn amodal completion the mind in some sense completes the visual perceptual representation of a scene by representing parts of the scene hidden behind other objects. Cognitive science has had a lot to say about how amodal completion occurs but has had little to say about the format of the representations involved and the way in which they represent. Some philosophers hold that amodal completions take the form of sensory imaginings of the occluded portions. This theory poses a puzzle for both philosophy and neuroscience about how the occluded parts are imagined to be located relative to the unoccluded parts. A better theory begins with the observation that for many purposes it is useful to suppose that the mind contains mental models of three-dimensional structure. Visual perceptions and mental images may be conceived as mental models that represent external scenes by virtue of homomorphism and which possess both a deep aspect, representing both visible and occluded three-dimensional structure, and a perspectival aspect, representing only an arrangement of visible surfaces. In these terms we can explain various problem-solving abilities, such as the ability to imagine what a scene will look like from another point of view. Amodal completions can be treated as deep perceptual representations of three-dimensional structure. Thus amodal completions do not consist of mental imagery, but they can be used to generate mental imagery representing how a scene would look from alternative points of view.

Пациент с негнойным тромбозом кавернозного синуса и кластерной головной болью: роль телемедицинской консультации.

Cerebral venous thrombosis may be due to partial or complete occlusion of cortical veins or cerebral venous sinuses, of which cavernous sinus thrombosis is the least frequently diagnosed (1.3% of cases). Septic thrombosis of the cavernous sinus is more frequently diagnosed, but aseptic variant of development is also possible. The aim of this work was to present a clinical case of a change in the diagnostic hypothesis during the observation by a neurologist of a telemedicine service of a patient with cluster headache and further detection of non-septic thrombosis of the cavernous sinus.

Midterm Outcome of Branch Vessel Stenting for Superior Mesenteric Artery Malperfusion Complicating with Acute Aortic Dissection.

To investigate the midterm stent patency and patient prognosis after stenting for superior mesenteric artery malperfusion complicating with acute aortic dissection. Thirteen patients who underwent branch vessel stenting for superior mesenteric artery malperfusion between 2011 and 2021 in six institutions were retrospectively reviewed. By comparing pre- and postoperative computed tomography scans in the same plane, the length of the stent implanted in the superior mesenteric artery and the stent-to-vessel diameter ratio were measured. The technical and clinical success of stenting, midterm patient prognosis, and stent patency were evaluated. Superior mesenteric artery stenting was technically successful in 12 patients (92.3%). The mean length of the stents implanted in the superior mesenteric artery was 61.3 ± 39.4 mm (range, 14-127 mm). The mean proximal and distal stent-to-vessel diameter ratios were 1.02 ± 0.16 and 1.30 ± 0.42, respectively. A weak correlation was found between the length of the stents implanted in the superior mesenteric artery and the distal stent-to-vessel diameter ratio (R2 = 0.34). Two major complications occurred, one of which resulted in death within 30 days, and 12 (92.3%) were clinically successful. Of these 12 patients, no recurrent intestinal ischemia occurred during the follow-up duration (mean, 45.2 months). Partial occlusion of the stent distal edge without intestinal ischemia was observed in one patient (distal stent-to-vessel diameter ratio = 2.33) 42 months after stenting. The overall survival rate and primary stent patency rate were 84.6% and 91.7%, respectively. Midterm stent patency and survival after superior mesenteric artery stenting for malperfusion were acceptable.

Preliminary results of intracranial aneurysm treatment with derivo2heal embolization device

IntroductionThe Derivo 2 Heal Embolization Device (D2HED) is a novel flow diverter (FD) providing a fibrin-/heparin-based surface coating aiming at lower thrombogenicity. We evaluate periprocedural aspects and preliminary aneurysm occlusion efficacy for intracranial aneurysm treatment.MethodsThirty-four D2HEDs deployments (34 aneurysms, 32 patients) between 04/2021 and 10/2023 were analyzed. All patients were under dual antiplatelet therapy (dAPT). Periprocedural details, adverse events, and follow-up (FU) imaging were reviewed by consultant-level neuroradiologists. Complication rates and aneurysm occlusion efficacy are compared with performance data of other FDs based on literature research.ResultsEach intervention succeeded in the deployment of one D2HED. Significant and/or increased intraaneurysmal contrast stagnation immediately after D2HED deployment was seen in 73.5% of cases according to O’Kelly-Marotta (OKM) grading scale. Clinically relevant early adverse events occurred in three patients: Among them two cases with fusiform aneurysms in the posterior circulation (ischemic events, early in-stent-thrombosis) and one patient (ischemic event) out of the majority of 31 treated internal carotid artery aneurysms (3,2%). Regarding mid-term FU (> 165 days), one aneurysm did not show progressive occlusion presumably caused by a prominent A1 segment arising from the terminal ICA aneurysm itself. Apart from that, mid-term complete / partial occlusion rates of 80% / 20% could be demonstrated.ConclusionOur case series - although suffering from restricted sample size - suggests a potential effectiveness of D2HED in managing intracranial aneurysms. Further studies with larger samples are warranted to quantify long-term occlusion efficacy and the impact of antithrombogenic surface coating on the necessary (d)APT.

CTM-YOLOv8n: A Lightweight Pedestrian Traffic-Sign Detection and Recognition Model with Advanced Optimization

Traffic-sign detection and recognition (TSDR) is crucial to avoiding harm to pedestrians, especially children, from intelligent connected vehicles and has become a research hotspot. However, due to motion blurring, partial occlusion, and smaller sign sizes, pedestrian TSDR faces increasingly significant challenges. To overcome these difficulties, a CTM-YOLOv8n model is proposed based on the YOLOv8n model. With the aim of extracting spatial features more efficiently and making the network faster, the C2f Faster module is constructed to replace the C2f module in the head, which applies filters to only a few input channels while leaving the remaining ones untouched. To enhance small-sign detection, a tiny-object-detection (TOD) layer is designed and added to the first C2f layer in the backbone. Meanwhile, the seventh Conv layer, eighth C2f layer, and connected detection head are deleted to reduce the quantity of model parameters. Eventually, the original CIoU is replaced by the MPDIoU, which is better for training deep models. During experiments, the dataset is augmented, which contains the choice of categories ‘w55’ and ‘w57’ in the TT100K dataset and a collection of two types of traffic signs around the schools in Tianjin. Empirical results demonstrate the efficacy of our model, showing enhancements of 5.2% in precision, 10.8% in recall, 7.0% in F1 score, and 4.8% in mAP@0.50. However, the number of parameters is reduced to 0.89M, which is only 30% of the YOLOv8n model. Furthermore, the proposed CTM-YOLOv8n model shows superior performance when tested against other advanced TSDR models.

Robotically assisted outflow graft anastomosis in minimally invasive left-ventricular assist device implantation: feasibility, surgeon comfort, and operative times in an anatomical study.

Upper hemi-sternotomy is a common approach for outflow graft anastomosis to the ascending aorta in minimally invasive left-ventricular assist device implantation. Right mini-thoracotomy may also be used, but use of robotic assistance has been reported only anecdotally. The aim of our study was to confirm the feasibility of robotically assisted suturing of the outflow graft anastomosis and to assess performance metrics for the robotic suturing part of the procedure. The procedure was carried out in eight cadaver studies by two surgeons. The assist device pump head was inserted through a left-sided mini-thoracotomy and the outflow graft was passed toward a right-sided second interspace mini-thoracotomy through the pericardium. After placement of a partial occlusion clamp on the ascending aorta, a longitudinal aortotomy was performed and the outflow graft to ascending aorta anastomosis was carried out robotically. The procedure was feasible in all eight attempts. The mean outflow graft anastomotic time was 20.1 (SD 6.8) min and the mean surgeon confidence and comfort levels to complete the anastomoses were 8.3 (SD 2.4) and 6.9 (SD2.2), respectively, on a ten-grade Likert scale. On open inspection of the anastomoses, there was good suture alignment in all cases. We conclude that suturing of a left-ventricular assist device outflow graft to the human ascending aorta is very feasible with good surgeon comfort. Anastomotic times are acceptable and suture placement can be performed with appropriate alignment.

Flow Diverter

The flow diverter is a relatively new but revolutionary technology in the realm of Endo vascular management of complex cerebral aneurysms. The traditional approach in the past has been stent deployment assisted coil embolisation. However, this maybe associated with partial occlusion or late recanalisation of the aneurysm. While planning the procedure for any cerebral aneurysm, the neurosurgeon needs to consider the morphology of the intracranial aneurysm as well as its proximity to the vascular branches and perforators. Giant (>25mm diameter), large (>10mm diameter), wide necked and fusiform aneurysms are the most challenging ones to treat.(1) The flow diverter works on the following principles (a)the stent deployed disrupts the blood flow from the parent vessel into the aneurysm (b) the stent works like a scaffolding for the growth of endothelial cells and separates the aneurysm from the parent vessel and gradually blocks it.(2) It is inducing endoluminal reconstruction in contrast to endosaccular filling in the older procedures. Moreover, it spares the origin of perforators from getting occluded. The sac gradually shrinks and finally collapses. This has excellent outcomes in comparison to conventional procedures for large or wide-necked aneurysms. This fascinating, innovative technology is associated with lesser complications and higher success rates. It is backed by landmark trials including the ‘Pipeline Embolisation Device for the Intracranial treatment of Aneurysms (PITA)’ trial and the ‘Pipeline for Uncoilable or Failed Aneurysms (PUFs) trial.(1) The device has thrombogenic potential and the patient needs to be on anti platelet therapy to prevent thromboembolism and late in-stent stenosis. A diversified complex case of multiple giant internal carotid artery aneurysms managed by latest phenomenal advanced technique of flow diversion in Neurointervention spectrum, that is, FLOW DIVERTER (FD). This young lady presented with sudden onset right sided complete opthalmoplegia and headache. Her investigations revealed bilateral ICA large to giant aneurysms. Considering all aspects of her case, she was counselled and planned for FD placement with some coils.

INVESTIGATING THE RELATIONSHIP BETWEEN BLEEDING, CLOTTING, AND COAGULOPATHY DURING AUTOMATED PARTIAL REBOA STRATEGIES IN A HIGHLY LETHAL PORCINE HEMORRHAGE MODEL.

Background: Death due to hemorrhagic shock, particularly, noncompressible truncal hemorrhage, remains one of the leading causes of potentially preventable deaths. Automated partial and intermittent resuscitative endovascular balloon occlusion of the aorta (i.e., pREBOA and iREBOA, respectively) are lifesaving endovascular strategies aimed to achieve quick hemostatic control while mitigating distal ischemia. In iREBOA, the balloon is titrated from full occlusion to no occlusion intermittently, whereas in pREBOA, a partial occlusion is maintained. Therefore, these two interventions impose different hemodynamic conditions, which may impact coagulation and the endothelial glycocalyx layer. In this study, we aimed to characterize the clotting kinetics and coagulopathy associated with iREBOA and pREBOA, using thromboelastography (TEG). We hypothesized that iREBOA would be associated with a more hypercoagulopathic response compared with pREBOA due to more oscillatory flow. Methods: Yorkshire swine (n = 8/group) were subjected to an uncontrolled hemorrhage by liver transection, followed by 90 min of automated pREBOA, iREBOA, or no balloon support (control). Hemodynamic parameters were continuously recorded, and blood samples were serially collected during the experiment (i.e., eight key time points: baseline (BL), T0, T10, T30, T60, T90, T120, T210 min). Citrated kaolin heparinase assays were run on a TEG 5000 (Haemonetics, Niles, IL). General linear mixed models were employed to compare differences in TEG parameters between groups and over time using STATA (v17; College Station, TX), while adjusting for sex and weight. Results: As expected, iREBOA was associated with more oscillations in proximal pressure (and greater magnitudes of peak pressure) because of the intermittent periods of full aortic occlusion and complete balloon deflation, compared to pREBOA. Despite these differences in acute hemodynamics, there were no significant differences in any of the TEG parameters between the iREBOA and pREBOA groups. However, animals in both groups experienced a significant reduction in clotting times (R time: P < 0.001; K time: P < 0.001) and clot strength (MA: P = 0.01; G: P = 0.02) over the duration of the experiment. Conclusions: Despite observing acute differences in peak proximal pressures between the iREBOA and pREBOA groups, we did not observe any significant differences in TEG parameters between iREBOA and pREBOA. The changes in TEG profiles were significant over time, indicating that a severe hemorrhage followed by both pREBOA and iREBOA can result in faster clotting reaction times (i.e., R times). Nevertheless, when considering the significant reduction in transfusion requirements and more stable hemodynamic response in the pREBOA group, there may be some evidence favoring pREBOA usage over iREBOA.

Use of the Scepter Dual-Lumen Balloon Catheter for Transarterial Onyx Embolization of Cranial Dural Arteriovenous Fistulas

Dual-lumen balloon microcatheters allow for controlled anterograde flow of Onyx while providing proximal flow arrest, thereby obviating the need for a second microcatheter or Onyx plug formation. We sought to assess the safety and efficiency of the Scepter dual-lumen balloon microcatheter in trans arterial Onyx embolization of intracranial dural arteriovenous fistulas (DAVFs). We conducted a retrospective study of 36 patients with cranial DAVFs in which a Scepter balloon microcatheter was used between 2016 and2023. Our study comprised 36 patients, mostly male (n= 23, 63.8%) with a mean age of 60.8 years. Most DAVFs were in the occipital lobe (n= 24, 66.7%), and 50% had external carotid artery supply from the occipital artery. Eighteen (50%) of DAVFs were Cognard type III and IV, respectively. About one third (33.3%, n= 12) of the DAVFs drained into the transverse sigmoid junction, and 27.7% (n= 10) had direct cortical venous drainage into supratentorial or posterior fossa veins. Complete occlusion was obtained in 22 (61.1%) patients while partial occlusion was observed in 14 (38.9%) patients. One patient (2.8%) developed a retroperitoneal hematoma. At final follow-up, complete occlusion was observed in 21 (77.8%) and partial occlusion was observed in 8 (22.2%). Recurrence was observed in 4/30 (13.3%) patients, and retreatment was required in 6 (18.75%) cases. At midterm follow-up, our study showed low morbidity and modest complete occlusion rates using the Scepter for transarterial Onyx embolization of high-grade DAVFs.

Long-term risk of hemorrhage and mortality after treatment of high-grade intracranial dural arteriovenous fistulas

BackgroundDespite recent multi-institutional efforts, long-term data on clinical and radiological outcomes after treatment of high-grade dural arteriovenous fistulas (dAVFs) remain scarce. This study aimed to evaluate the long-term risk of...

Metabolic effects of training with blood flow restriction

Relevance. Training with limited blood flow, which is performed with partial vascular occlusion using inflatable cuffs, can cause an increase in skeletal muscle mass and strength, similar to those observed with classical high-intensity training with weights, although with a noticeably lower mechanical load. Performing a load with a restriction of blood flow leads to the accumulation of metabolites, recruitment of motor neurons with a higher excitation threshold, edema of muscle cells, an increase in the concentration of reactive oxygen species, which, in turn, contributes to hypertrophy of muscle fibers, increased muscle strength, mitochondrial biogenesis, angiogenesis, increased activity of glucose transporters. Based on this, training with limited blood flow should have a positive effect on metabolic health.The aim of the study is a theoretical analysis of the metabolic effects of blood flow restriction training in healthy individuals and in clinical populations.Methods and organization of the study - this review examines the metabolic effects of TOK in both healthy and clinical populations.Conclusions. BFR can be considered as a potential method for improving muscle function and metabolism of glucose, triglycerides and fatty acids.

Evaluating Visual Dependence in Postural Stability Using Smartphone and Stroboscopic Glasses

This study explores the efficacy of integrating stroboscopic glasses with smartphone-based applications to evaluate postural control, offering a cost-effective alternative to traditional forceplate technology. Athletes, particularly those with visual and visuo-oculomotor enhancements due to sports, often suffer from injuries that necessitate reliance on visual inputs for balance—conditions that can be simulated and studied using visual perturbation methods such as stroboscopic glasses. These glasses intermittently occlude vision, mimicking visual impairments that are crucial in assessing dependency on visual information for postural stability. Participants performed these tasks under three visual conditions: full vision, partial vision occlusion via stroboscopic glasses, and no vision (eyes closed), on foam surfaces to induce postural instability. The use of a smartphone app to measure postural sway was validated against traditional force plate measurements, providing a comparative analysis of both tools under varied sensory conditions. We investigated postural parameters like anterior–posterior and medial–lateral sway ranges, root mean square values, 95% confidence ellipse area, and sway velocity and median dominant sway frequency from both the smartphone and the force plates. Our findings indicate that force plates exhibit high sensitivity to various visual conditions, as evidenced by significant differences observed in certain postural parameters, which were not detected by smartphone-based measurements. Overall, our findings indicate that smartphones show promise as a cost-effective alternative to force plate measurements for routine monitoring of postural control in sports, although they may not achieve the same level of accuracy as force plates. The integration of stroboscopic glasses further refined the assessment by effectively simulating visual impairments, thereby allowing precise evaluation of an individual’s ability to maintain balance under visually perturbed conditions.

Integrating local and distant radiation-induced lung injury: Development and validation of a predictive model for ventilation loss.

Investigations on radiation-induced lung injury (RILI) have predominantly focused on local effects, primarily those associated with radiation damage to lung parenchyma. However, recent studies from our group and others have revealed that radiation-induced damage to branching serial structures such as airways and vessels may also have a substantial impact on post-radiotherapy (RT) lung function. Furthermore, recent results from multiple functional lung avoidance RT trials, although promising, have demonstrated only modest toxicity reduction, likely because they were primarily focused on dose avoidance to lung parenchyma. These observations emphasize the critical need for predictive dose-response models that effectively incorporate both local and distant RILI effects. We develop and validate a predictive model for ventilation loss after lung RT. This model, referred to as P+A, integrates local (parenchyma [P]) and distant (central and peripheral airways [A]) radiation-induced damage, modeling partial (narrowing) and complete (collapse) obstruction of airways. In an IRB-approved prospective study, pre-RT breath-hold CTs (BHCTs) and pre- and one-year post-RT 4DCTs were acquired from lung cancer patients treated with definitive RT. Up to 13 generations of airways were automatically segmented on the BHCTs using a research virtual bronchoscopy software. Ventilation maps derived from the 4DCT scans were utilized to quantify pre- and post-RT ventilation, serving, respectively, as input data and reference standard (RS) in model validation. To predict ventilation loss solely due to parenchymal damage (referred to as P model), we used a normal tissue complication probability (NTCP) model. Our model used this NTCP-based estimate and predicted additional loss due radiation-induced partial or complete occlusion of individual airways, applying fluid dynamics principles and a refined version of our previously developed airway radiosensitivity model. Predictions of post-RT ventilation were estimated in the sublobar volumes (SLVs) connected to the terminal airways. To validate the model, we conducted a k-fold cross-validation. Model parameters were optimized as the values that provided the lowest root mean square error (RMSE) between predicted post-RT ventilation and the RS for all SLVs in the training data. The performance of the P+A and the P models was evaluated by comparing their respective post-RT ventilation values with the RS predictions. Additional evaluation using various receiver operating characteristic (ROC) metrics was also performed. We extracted a dataset of 560 SLVs from four enrolled patients. Our results demonstrated that the P+A model consistently outperformed the P model, exhibiting RMSEs that were nearly half as low across all patients (13±3 percentile for the P+A model vs. 24±3 percentile for the P model on average). Notably, the P+A model aligned closely with the RS in ventilation loss distributions per lobe, particularly in regions exposed to doses ≥13.5Gy. The ROC analysis further supported the superior performance of the P+A model compared to the P model in sensitivity (0.98vs. 0.07), accuracy (0.87vs. 0.25), and balanced predictions. These early findings indicate that airway damage is a crucial factor in RILI that should be included in dose-response modeling to enhance predictions of post-RT lung function.

Multi-dimensional CNN Based Feature Extraction with Feature Fusion and SVM for Human Activity Recognition in Surveillance Videos

Background/Objectives: The accurate recognition of human activities from video sequences is very challenging due to low resolution, cluttered background, partial occlusion, and different viewpoints. Machine learning (ML) based automated HAR from surveillance videos is required with the fusion of various feature extraction techniques. Methods: In this paper, SVM with feature fusion is utilized for automatic recognition from surveillance videos. A Histogram of Oriented Gradient (HOG) is used to segment the frame to differentiate humans from other objects or background noise in the input video frames. The multi-feature extraction can be accomplished in terms of Gabor Wavelet Transform (GWT), Autocorrelogram, Gray-Level Co-Occurrence Matrix (GLCM), HSV histogram, and Multi-dimensional CNN. The proposed approach is implemented in MATLAB software and compared with existing approaches like Space-Time Interest Point (STIP) and Histogram of Optical Flow (HOF). Findings: The proposed approach outperforms the existing approaches in terms of reduced time consumption and high accuracy, 99.886% when using the UCF101 dataset and 99.538% when using the UTKinect dataset. Novelty: The most discriminative feature information is obtained with the feature-level fusion technique. From the feature information, various human actions are recognized with the classification algorithm. Keywords: Human activity recognition, Machine Learning, Surveillance Videos, Human detection algorithm, Feature extraction, SVM classifier

Apple-and-pin drawings by blind novices show occluded features: region theory

Abstract Sighted children drawing an apple with a pin through it show the hidden parts of the pin. That is, not only is the pin shown running towards the apple and out the other side, it is also shown inside the apple, without a single break, and so the sketch depicts the occluded parts of the pin. Several investigators have offered theories of the observation. We report here on tangible raised-line drawings by young blind people who are novices at drawing. They also include occluded segments of the pin. To explain the drawings we use the John Willats region theory. In this account, enclosed regions represent the volumes of 3D objects. According to region theory, what is in the interior of an object should be shown in the drawing even if it cannot be seen or touched. As a result, since occluded parts of the pin are inside the apple, blind children, like sighted children, include them in their drawings. In region theory, for both the blind and the sighted, long lines on a 2D pictorial surface represent elongated objects in the scene and regions on the surface represent 3D objects and their contents. The basis of region theory may be that sensory information for pins and lines has high-frequency components, and for apples and regions has lower-frequency components.

PREBOA vs ER-REBOA impact on blood utilization and resuscitation requirements: A pilot analysis.

Partial occlusion of the aorta is a resuscitation technique designed to maximize proximal perfusion while allowing a graduated amount of distal flow to reduce the ischemic sequelae associated with complete aortic occlusion. The pREBOA catheter affords the ability to titrate perfusion as hemodynamics allows, however, the impact of this new technology for REBOA on blood use and other resuscitative requirements is currently unknown. We hypothesize pREBOA's ability to provide partial occlusion, when appropriate, decreases overall resuscitative requirements when compared to ER-REBOA. The entire AAST AORTA Registry was used to compare resuscitation requirements between all ER-REBOA and pREBOA. Unpaired t-tests were used to compare resuscitation strategies including packed red blood cells (PRBCs), fresh frozen plasma (FFP), platelets, cryoprecipitate, crystalloids, and need for pressors. When comparing ER-REBOA (n=800) use to pREBOA (n=155), initial patient presentations were similar except for age (44 vs 40 p=0.026) and rates of blunt injury (78.4% vs 78.7% p<0.010). Zone-1 occlusion was used less often in ER-REBOA (65.8 vs 71.7 p=0.046). Partial occlusion was performed in 85% of pREBOA compared to 11% in ER-REBOA (p<0.050). Vitals at the time of REBOA were worse in ER-REBOA, and received significantly more units of PRBCs, FFP, platelets, and liters of crystalloids than pREBOA (p<0.05). Rates of ARDS and septic shock were lower in pREBOA (p<0.05). When comparing pREBOA to ER-REBOA, there has been a rise in Zone-1 and partial occlusion. In our pilot analysis of the AORTA Registry, there was a reduction in administration of pRBC, FFP, platelets, and crystalloids. Though further prospective studies are required, this is the first to demonstrate an association between pREBOA, partial occlusion, and reduced blood use and resuscitative requirements.

Efficiency of cavitary varnishes containing experimental bioglass particles in the occlusion of dentinal tubules.

This research aims to evaluate the efficiency of cavitary varnishes containing experimental bioglasses in the occlusion of dentinal tubules. One hundred and sixty-eight cervical buccal dentin samples were obtained from bovine teeth. Samples were randomized into the following groups: I. Distilled Water (DW); II. Cavity Varnish (CV); III. Colgate® Sensitive Pro-Relief™ (CS); IV. 45S5 Bioglass (45S5); V. KSr Bioglass strontium potassium (KSr); VI. P Bioglass phosphorus (P); and VII. PSi Bioglass phosphorus silica (PSi). The treatments were applied to the surfaces of the samples, which were then subjected to simulated brushing. The samples were analyzed for a) characterization of bioactive glasses; b) surface roughness; c) descriptive analysis of the dentin surface; d) total versus occluded number of dentinal tubules; e) diameter of the dentinal tubules; f) chemical composition of the dentin surfaces, and g) dentin permeability. All groups treated with biomaterials without the brushing challenge showed an increase in roughness and (total or partial) occlusion of the dentinal tubules. The PSi group had the best values for occlusion, while the KSr group had the highest calcium and phosphorus concentrations. After the brushing challenge the roughness was controlled by the presence of biomaterials; 45S5, KSr, and PSi showed occlusion of the dentin tubules. All bioactive glasses showed reduced tooth permeability compared to distilled water. The PSi group had the smallest tubule diameter and highest phosphorus concentration. KSr and PSi bioglasses are promising materials for dentin occlusion and remineralization and are promising new biomaterials for the treatment of dentin hypersensitivity.

Using Deep Learning to Increase Eye-Tracking Robustness, Accuracy, and Precision in Virtual Reality.

Algorithms for the estimation of gaze direction from mobile and video-based eye trackers typically involve tracking a feature of the eye that moves through the eye camera image in a way that covaries with the shifting gaze direction, such as the center or boundaries of the pupil. Tracking these features using traditional computer vision techniques can be difficult due to partial occlusion and environmental reflections. Although recent efforts to use machine learning (ML) for pupil tracking have demonstrated superior results when evaluated using standard measures of segmentation performance, little is known of how these networks may affect the quality of the final gaze estimate. This work provides an objective assessment of the impact of several contemporary ML-based methods for eye feature tracking when the subsequent gaze estimate is produced using either feature-based or model-based methods. Metrics include the accuracy and precision of the gaze estimate, as well as drop-out rate.

A RARE COMPLICATION OF MITRAL TEER PROCEDURE: CLIP LATE DETACHMENT AND EMBOLIZATION

Abstract Intraprocedural and late complications of MitraClip implantation have already been described. This report highlights the importance of conventional surgical options in the event of percutaneous treatment failure. An 85–year–old woman with a history of chronic anemia, and thalassemia Minor was referred to our clinic for severe mitral regurgitation (MR) due to a P2 flail with significant calcification of the posterior mitral annulus. During the Heart Team discussion, age and comorbidities led to consider the patient eligible for TEER with the MitraClip system (EuroSCORE II 9,34%; STS score 7,47%). TEER procedure was uneventful: one XTW was deployed at the level of the flail (A2–P2), a second XTW was then placed more lateral to treat a separate residual jet, and one NTW was finally placed between them. MR reduction was considered acceptable (moderate MR, mean grad 6 mmHg). After two months, symptoms worsened, and TTE showed severe MR (no device detachment) with increased sPAP and associated moderate TR. A couple of weeks later, the patient was hospitalized. Chest X–ray revealed clip embolization confirmed by coronary angiography that showed an XTW Clip embolized to the Right coronary sinus with partial occlusion of the ostium. Percutaneous clip retrieval is described in the literature, but the embolized device position and the presence of recurrent severe MR led us to prefer an urgent surgical intervention. Under CPB, the embolized XTW was easily retrieved through a small aortotomy; the intervention was completed by mitral valve replacement and tricuspid valve repair. The postoperative course was uneventful. Predischarge TTE showed normal mitral bioprosthesis function, mild AR, mild TR, and preserved LV function. DISCUSSION Clip embolization is a rare but potentially critical complication of TEER and can happen periprocedurally or on early follow–up. Single leaflet detachment is more common, but complete detachment and embolization can occur. Therapeutic options are represented by surgical or transcatheter approaches according to embolization sites and patient comorbidities. In our case, the risk of potential coronary obstruction or thrombosis and the concomitant need for MR treatment have led us to consider surgery as the first option. CONCLUSION TEER can be graved by acute or late complications. The best approach has to be tailored to each patient, and surgery can be an effective and safe option even for initially discarded high–risk patients.

Feasibility of Intraoperative Proctosigmoidoscopy After Discoid Bowel Resection for Deep Infiltrating Endometriosis: A Pilot Multicenter Study

Although surgery is the gold standard treatment for pain refractory to medical management or partial occlusion owing to rectosigmoid endometriosis, surgical resection can be associated with major perioperative complications. From general surgery experience, intraoperative proctosigmoidoscopy has shown encouraging results as a feasible, safe, and effective technique in reducing the risk of complications related to intestinal anastomosis after segmental resection. Unfortunately, there are no studies evaluating its role after discoid resection for rectosigmoid endometriosis. A pilot, multicentric, observational, prospective, cohort study. Two academic hospitals, from March 1 to December 31, 2022. We enrolled all consecutive fertile-age patients affected by symptomatic endometriosis scheduled for laparoscopic discoid bowel resection. Inclusion criteria were (1) age between 18 and 50 years, (2) diagnosis of rectosigmoid endometriosis performed by transvaginal ultrasound and/or magnetic resonance imaging, and (3) women scheduled for laparoscopic discoid bowel resection of endometriosis at low risk of segmental resection. During data analysis, enrolled patients were divided into 2 study groups for comparisons based on whether or not the intraoperative proctosigmoidoscopy was performed upon surgeons' discretion after discoid resection for treating endometriosis, in addition to standard integrity tests. Primary outcome was the rate of intraoperative proctosigmoidoscopy success. Secondary study outcomes were the differences between the intraoperative proctosigmoidoscopy group and the nonintraoperative proctosigmoidoscopy group in (1) mean of total operative time and (2) rate of perioperative complications. A total of 28 patients were enrolled and equally distributed in the 2 groups. The rate of intraoperative proctosigmoidoscopy success was 86%. No significant difference was reported between the 2 groups in terms of total operative time (p = .1) and intraoperative and postoperative complications (p = .5 and p = 1, respectively), with no surgical complication related to intraoperative proctosigmoidoscopy. Intraoperative proctosigmoidoscopy seems as a feasible and non-time-consuming intraoperative procedure in women undergone discoid resection for rectosigmoid endometriosis. Larger studies with longer follow-up period are necessary to confirm our findings and assess clinical benefits over standard procedure.