Anatomical Shape Research Articles

Image2SSM: Reimagining Statistical Shape Models from Images with Radial Basis Functions.

Statistical shape modeling (SSM) is an essential tool for analyzing variations in anatomical morphology. In a typical SSM pipeline, 3D anatomical images, gone through segmentation and rigid registration, are represented using lower-dimensional shape features, on which statistical analysis can be performed. Various methods for constructing compact shape representations have been proposed, but they involve laborious and costly steps. We propose Image2SSM, a novel deep-learning-based approach for SSM that leverages image-segmentation pairs to learn a radial-basis-function (RBF)-based representation of shapes directly from images. This RBF-based shape representation offers a rich self-supervised signal for the network to estimate a continuous, yet compact representation of the underlying surface that can adapt to complex geometries in a data-driven manner. Image2SSM can characterize populations of biological structures of interest by constructing statistical landmark-based shape models of ensembles of anatomical shapes while requiring minimal parameter tuning and no user assistance. Once trained, Image2SSM can be used to infer low-dimensional shape representations from new unsegmented images, paving the way toward scalable approaches for SSM, especially when dealing with large cohorts. Experiments on synthetic and real datasets show the efficacy of the proposed method compared to the state-of-art correspondence-based method for SSM.

Progressive DeepSSM: Training Methodology for Image-To-Shape Deep Models.

Statistical shape modeling (SSM) is an enabling quantitative tool to study anatomical shapes in various medical applications. However, directly using 3D images in these applications still has a long way to go. Recent deep learning methods have paved the way for reducing the substantial preprocessing steps to construct SSMs directly from unsegmented images. Nevertheless, the performance of these models is not up to the mark. Inspired by multiscale/multiresolution learning, we propose a new training strategy, progressive DeepSSM, to train image-to-shape deep learning models. The training is performed in multiple scales, and each scale utilizes the output from the previous scale. This strategy enables the model to learn coarse shape features in the first scales and gradually learn detailed fine shape features in the later scales. We leverage shape priors via segmentation-guided multi-task learning and employ deep supervision loss to ensure learning at each scale. Experiments show the superiority of models trained by the proposed strategy from both quantitative and qualitative perspectives. This training methodology can be employed to improve the stability and accuracy of any deep learning method for inferring statistical representations of anatomies from medical images and can be adopted by existing deep learning methods to improve model accuracy and training stability.

Fully Bayesian VIB-DeepSSM.

Statistical shape modeling (SSM) enables population-based quantitative analysis of anatomical shapes, informing clinical diagnosis. Deep learning approaches predict correspondence-based SSM directly from unsegmented 3D images but require calibrated uncertainty quantification, motivating Bayesian formulations. Variational information bottleneck DeepSSM (VIB-DeepSSM) is an effective, principled framework for predicting probabilistic shapes of anatomy from images with aleatoric uncertainty quantification. However, VIB is only half-Bayesian and lacks epistemic uncertainty inference. We derive a fully Bayesian VIB formulation and demonstrate the efficacy of two scalable implementation approaches: concrete dropout and batch ensemble. Additionally, we introduce a novel combination of the two that further enhances uncertainty calibration via multimodal marginalization. Experiments on synthetic shapes and left atrium data demonstrate that the fully Bayesian VIB network predicts SSM from images with improved uncertainty reasoning without sacrificing accuracy.

Kreativitas Tata Cahaya Moderen Dalam Pertunjukan Wayang Kulit Bali Masa Kini

The problem of puppet show lighting in the puppet show is a very important element to be carefully considered as it is a medium in projecting shadow puppets on the screen.Because lighting is very influential ( the result of the projected shadow) that project the identity of Balinese leather puppet figures, which contain aesthetic and symbolic values. In principle, the use of lighting in puppet shows should be able to produce a high carrying capacity, not merely the modern practicality but it also able to illuminate according to the form of puppets in a surreal form.It also supports the expected dramatic atmosphere, such as scenery or background depiction,in order to anticipate the shift in the thoughts of contemporary puppet viewers who tend to be realists. In line with the objective of this research which is to produce the anatomical shape of Balinese Wayang Kulit with an ideal proportions of electric lighting. It also aims to produce a scenery that is in accordance to the style of Balinese Wayang Kulit which is not realistic. The method used is the Practice-based Research method , a creating and studying works of art based method. This practice-can produce the ideal shape and anatomy of wayang and the harmony between scenery and wayang.

Survival rates of anatomically shaped and tapered slip cemented femoral implants: an analysis of 76,281 femoral implants of the Dutch arthroplasty register (LROI).

In cemented total hip arthroplasty (THA) various shapes and geometries of femoral implants are in use. Collarless, polished, and tapered (CPT) implants, and anatomically shaped (AS) implants are most commonly used. Due to their different design features, this might lead to different survival outcomes. In this register-based study, overall implant survival and short-term complications of CPT and AS cemented implants were evaluated. Data of the Dutch Arthroplasty Register (LROI) were used. Cemented femoral implants, which could be classified as CPT or AS were included in this study. Implants were excluded when no classification could be made or if implanted <100 times. Survival analyses were performed using Kaplan-Meier survival analysis and multivariable Cox-proportional hazard analysis. 76,281 cemented THAs were included. At a mean of 5.1 years follow-up (SD 3.1, range 0-12 years), the overall survival of the AS implants was higher compared with the CPT implants, with a survival, of 99.2% and 99.0% respectively (log-rank; p < 0.001). Multivariable regression analysis revealed a higher rate for revision because of loosening of the AS implants (HR 2; CI, 1.4-3.1). AS implants had a lower rate for periprosthetic fractures compared with the CPT implants (HR 0.13; CI, 0.07-0.23). Both designs show excellent overall survival rates at short-term follow-up. There is a higher overall survival of AS implants when compared with CPT implants. Revision for implant loosening, however, was statistically significantly higher in AS implants when compared with the CPT implants.

A High-Fidelity Artificial Urological System for the Quantitative Assessment of Endoscopic Skills.

Minimally-invasive surgery is rapidly growing and has become a standard approach for many operations. However, it requires intensive practice to achieve competency. The current training often relies on animal organ models or physical organ phantoms, which do not offer realistic surgical scenes or useful real-time feedback for surgeons to improve their skills. Furthermore, the objective quantitative assessment of endoscopic skills is also lacking. Here, we report a high-fidelity artificial urological system that allows realistic simulation of endourological procedures and offers a quantitative assessment of the surgical performance. The physical organ model was fabricated by 3D printing and two-step polymer molding with the use of human CT data. The system resembles the human upper urinary tract with a high-resolution anatomical shape and vascular patterns. During surgical simulation, endoscopic videos are acquired and analyzed to quantitatively evaluate performance skills by a customized computer algorithm. Experimental results show significant differences in the performance between professional surgeons and trainees. The surgical simulator offers a unique chance to train endourological procedures in a realistic and safe environment, and it may also lead to a quantitative standard to evaluate endoscopic skills.

Gel Cohesivity and Breast Augmentation: Applications to Clinical Practice.

Abstract Matching breast implant gel cohesivity to the patient’s needs based on anatomical and soft tissue considerations and patient preferences is essential to optimizing aesthetic outcomes and patient satisfaction. Generally, gel cohesivity contributes to the feel and shape of the breast, which reflects volume distribution within the breast. Studies on the physical properties of silicone gel breast implants have established the relative cohesivity of implants from several manufacturers. Comprehensive patient education, tissue-based preoperative planning, and a thorough understanding of how implant properties may affect outcomes are recommended before breast augmentation. This review summarizes the literature on breast implant physical properties with a focus on gel cohesivity and translates gel cohesivity to practical considerations in choosing the right implant for the right patient in primary augmentation. Based on clinical experience, the authors generally recommend lower-cohesivity implants for patients who desire a tapered upper pole or a natural appearance/“anatomic shape” as well as for those with a high body mass index or a large amount of native breast tissue. Medium-cohesivity implants are most widely used and are appropriate for those with ptosis/augmentation mastopexy, patients with tight skin envelope, and for those seeking upper pole fullness. A high-cohesivity implant is recommended for patients desiring a round shape, those with constricted lower poles, and patients with a postpartum loose envelope, a thin, soft tissue envelope, or fibrous breast tissue.

Y-shape osteotomy combined with subtalar arthrodesis for calcaneus malunion: a retrospective study

BackgroundThis retrospective study aimed to introduce a novel method for simultaneous Y-shape osteotomy combined with subtalar arthrodesis for calcaneus malunion and to evaluate the feasibility of this method.MethodsWe retrospectively analysed the clinical and imaging data of 11 patients with calcaneus malunion treated using Y-shape osteotomy and subtalar arthrodesis who were admitted to our hospital from June 2018 to October 2020. The patients included 9 males and 2 females aged from 24 to 69 years old, with an average age of 42.18 years. The clinical and radiological results were assessed with the Visual Analogue Scale (VAS) pain score and American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score. In addition, functional recovery and general quality of life were evaluated using the 12-Item Short-Form Survey (SF-12).ResultsAll radiological parameters were significantly improved at the last follow-up, with increases of 14.37°, 9.18°, and 4.51 mm in the Böhler’s angle, calcaneal pitch angle, and talocalcaneal height, respectively, and decreases of 6.39 mm and 6.18° in the calcaneal width and Hindfoot alignment angle (p < 0.05). The mean AOFAS and VAS scores at the last follow-up improved compared with those preoperatively, from 34.18 ± 9.53 to 84.18 ± 11.59 and from 6.90 ± 1.22 to 1.90 ± 1.13, respectively (p < 0.05). The SF-12 physical and mental health scores were 49.65 ± 6.84 and 52.68 ± 7.88, respectively. Furthermore, the early postoperative complications included skin necrosis in one and sural neuralgia in one patient, and the late postoperative complication included ankle pain in one patient. No other complications, such as implant discomforts, malunion, nonunion and re-fracture, were presented.ConclusionThese results indicate that Y-shape osteotomy combined with subtalar arthrodesis is an effective new method for the treatment of calcaneal malunion. Advantages include improvement of the anatomic shape of the calcaneus and union rates for subtalar arthrodesis.

Using Optimal Transport to Improve Spherical Harmonic Quantification of Complex Biological Shapes.

The knowledge of the anatomical shape of both gross and microscopic structures is the key to understanding the effects of disease processes on cellular structure. Geometric morphometric methods, such as Procrustes superimposition, and Spherical Harmonics (SPHARM), have been used to capture the biological shape variation and group differences in morphology. Previous SPHARM-MAT techniques use the CALD algorithm to parameterize the mesh surface. It starts from initial mapping and performs local and global smoothing methods alternately to control the area and length distortions simultaneously. However, this parameterization may not be sufficient in complex morphological cases. To bridge this gap, we propose SPHARM-OT, an enhanced SPHARM surface modeling method using optimal transport (OT) for spherical parameterization. First, the genus 0 3D objects are conformally mapped onto a sphere. Then the optimal transport theory via spherical power diagram is introduced to minimize the area distortion. This new algorithm can effectively reduce the area distortion and lead to a better reconstruction result. We demonstrate the effectiveness of the method by applying it to the human sphenoidal paranasal sinuses.

The landscape of tumor cell states and spatial organization in H3-K27M mutant diffuse midline glioma across age and location

Histone 3 lysine27-to-methionine (H3-K27M) mutations most frequently occur in diffuse midline gliomas (DMGs) of the childhood pons but are also increasingly recognized in adults. Their potential heterogeneity at different ages and midline locations is vastly understudied. Here, through dissecting the single-cell transcriptomic, epigenomic and spatial architectures of a comprehensive cohort of patient H3-K27M DMGs, we delineate how age and anatomical location shape glioma cell-intrinsic and -extrinsic features in light of the shared driver mutation. We show that stem-like oligodendroglial precursor-like cells, present across all clinico-anatomical groups, display varying levels of maturation dependent on location. We reveal a previously underappreciated relationship between mesenchymal cancer cell states and age, linked to age-dependent differences in the immune microenvironment. Further, we resolve the spatial organization of H3-K27M DMG cell populations and identify a mitotic oligodendroglial-lineage niche. Collectively, our study provides a powerful framework for rational modeling and therapeutic interventions.

Abstract 10736: Statistical Shape Modeling Reveals Anatomic Shape Features Associated With the Outcome of Optimal Medical Therapy in Uncomplicated Type B Aortic Dissection

Introduction: Currently, Type B aortic dissection (TBAD) without the presence of either organ malperfusion or aortic rupture is managed with optimal medical therapy (OMT) consisting of an aggressive anti-hypertensive medical regimen and surveillance imaging. Although OMT achieves excellent early survival, the long-term outcomes with OMT alone remain poor. In this study, we identified anatomic shape features that correlate with OMT failure and aortic growth rates in uncomplicated TBAD via statistical shape modeling (SSM). Methods: Contrast CT scans of patients with acute uncomplicated TBAD were analyzed from 25 patients who were initially treated with OMT. OMT failure was defined as aortic intervention (surgical or endovascular repair, n = 8). Statistical shape models were constructed using principal component analysis (PCA) and partial least square regression (PLSR) to extract anatomic shape features from the aorta and flap geometries. For 14 of the 25 patients, additional follow-up CT scans (5 to 117 months) were used to quantify the rate of aortic expansion. Results: Four PCA (feature 5: p = 0.048, 12: p = 0.005, 14: p = 0.047, 24: p = 0.038) and two PLSR (feature 1: p = 0.000, 2: p = 0.004) shape features were effective at separating OMT failure patients and patients who were adequately treated with OMT. Two PCA features were moderately correlated with aortic growth rate (correlation coefficient, feature 11; r = 0.579, 21: r = 0.503). A PLSR feature was correlated with the growth rate (r = 0.867). Representative shape features are shown in Figure 1. Conclusions: Anatomic shape features extracted from SSM were correlated with the outcomes of OMT and aortic growth rate. SSM shape features may provide additional anatomic risk factors in addition to aortic diameter that predicts aneurysmal degeneration and the need for surgical intervention. Future investigations will incorporate the SSM shape features to determine the risk of OMT failure in uncomplicated TBAD patients.

Multimodal 3D printing of biodegradable shape memory elastomer resins for patient specific soft tissue repair

Acrylated poly(glycerol-dodecanedioate) (APGD), a biodegradable shape memory polymer, is a photocurable resin developed for 3D printing of biomaterial implants that is especially suited for minimally invasive procedures. 3D printing has numerous advantages over traditional manufacturing modalities including production of complex porous geometries, improved feature resolution, and lower production costs on a per part basis for low volume clinical production. Material extrusion (ME) and vat photopolymerization (VP) printing are two prevalent 3D printing modalities used in tissue engineering. Compared to VP printing, ME printing offers a higher degree of customization by allowing co- or multi-material prints, along with biologic cell printing. VP printing offers higher throughput and capability for printing more complex geometries, versus ME printing, with shorter manufacturing times, making it a more commercially viable choice for clinically translatable materials. Motivated by each printing modalities’ unique advantages, APGD resins for ME and VP printing were developed and assessed for crosslinker and photoinitiator (PI) concentration effect on resin time to gel point, storage modulus and viscosity. Increasing crosslinker concentration decreased the gel time and increased the storage modulus of cured resin. Significant differences in printed sample geometry along with material and mechanical properties resulted from using the two printing modalities. ME samples had larger void volume (6.1 ± 1.2% vs. 0.2 ± 0.4%), lower gel content (55.3 ± 2.6% vs. 68.7 ± 1.9%), and less shape fixity (77.4 ± 4.7 vs. 97.3 ± 3.7%) compared to VP samples. VP printing generated complicated 3D anatomic shapes of higher quality than ME printing. In conclusion, this manuscript provides the first report of APGD 3D printing that can be applied to shape memory, resorbable medical devices.

Ultrasonographic Evaluation of Soft Tissue Calcifications in the Head and Neck Region Detected on Panoramic Radiographs.

The aim of this study is to present a comparison between panoramic radiographs and USG imaging with a focus on revealing the advantages of USG over radiographs, and to show the distribution of calcifications detected in USG by considering the age and gender. A total of 148 patients with soft tissue calcifications as seen on panoramic radiographs were examined with USG imaging. Sialoliths, carotid artery calcifications, tonsilloliths, phleboliths and lymph node calcifications were examined in terms of anatomical localization, distribution and shape. In the USG evaluation of these 148 patients, soft tissue calcifications were observed in 113 (76.4%) patients. The mean age of the patients with calcification was 55.6 ± 13.1 (min: 22-max: 77). Bilateral calcifications were detected in 25 (22.1%) patients, whereas unilateral calcifications were found in 88 (77.9%) patients. While the rates of tonsilloliths, sialoliths, phleboliths, and lymph node calcifications were statistically similar in male and female patients, the rate of carotid artery calcifications was found to be higher in men than in women (P=0.017). No statistical significance was found between age groups in terms of the formation of soft tissue calcifications (P=0.117). Panoramic radiographs may mislead clinicians in the diagnosis and differential diagnosis of soft tissue calcifications in the head and neck region due to the presence of distortion, superpositions, metal artefacts, and ghost images. USG is an important diagnostic tool in determining the localization of soft tissue calcifications that can be confused on two-dimensional radiographs, their relationship with neighboring structures, and defining calcification. It can be used safely in the detection of soft tissue calcifications as it provides dynamic imaging without the use of radiation or contrast material compared to other advanced imaging methods.

Determine the functional and radiological outcome of T3 proximal femur nail in the treatment of intertrochanteric fracture of femur

&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt; T3 is the new generation nail used for fixation of intertrochanteric fractures. The lag screw is designed to transfer the load of the femoral head into the nail shaft by bridging the fracture line to allow fast and secure fracture healing. The load carrying thread design of the T3 lag screw provides large surface contact to the cancellous bone, this provides high resistance against cut out.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; 30 subjects attending the study were operated with T3 proximal femur nail in the treatment of intertrochanteric fracture of femur. Prospective, randomised case-controlled study done over period of 1 year.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Significant results were obtained while comparing the mean RUSH score and mean Harris hip score at different postoperative follow-up time intervals with good to excellent outcome and less operative time and low complications rate.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; T3 is the new generation nail used for fixation of intertrochanteric fractures and is a dependable implant for the fixation. It has good to excellent outcomes and takes less operative time with low complication rates. The anatomical shape of the nail is universal for all indications involving the treatment of intertrochanteric fractures. The load carrying thread design of the T3 lag screw provides large surface contact to the cancellous bone, thus providing high resistance against cut out. The set screw prevents rotation of the lag screw. The T3 has a single screw passing into the neck of the femur and its Set Screw that is passed into the proximal part of the femoral nail sits into the groove of the Lag screw, thus providing rotational stability.&lt;/p&gt;

Salvage Reconstruction of Oncologic Humeral Defects with Free Fibula Flap after Failure with Prosthesis-based Reconstruction

PURPOSE: Advancements in orthoplastic reconstructive surgery have enabled surgeons to perform limb salvage surgery successfully after long bone tumor extirpation of upper extremities. A variety of reconstructive options (allograft, prosthetics, allograft-prosthetic combination, non-vascularized autografts) exist for surgical rehabilitation of such cases. Even though reconstruction by prosthesis is most commonly used in this setting, the associated risks of mechanical failure, aseptic loosening, and infection, can potentially lead to failure and amputation. Furthermore, revision procedures of the primary surgery after implant failure are complicated by unfavorable local tissue properties like massive bone loss, unreliable local tissue, and osteopenic process of the host bone. Therefore, prosthetic reconstruction is usually undesirable; whereas vascularized bone flaps have proven to be an excellent alternative to restore the biomechanical framework of the limb. Herein, we present the free fibula flap (FFF) used to reconstruct oncological humeral defects previously treated with prosthetic based reconstruction which failed. METHOD: We conducted a retrospective review of patients who underwent salvage of the humeral reconstructions in which the prosthesis failed, during 2009 and 2019. We included patients with previous reconstruction of humeral defects only with prosthetic material and no tissue transfer. All cases were reconstructed with the FFF. The Musculoskeletal Tumor Society (MSTS) scoring system was used to evaluate functional outcomes. RESULTS: The mean age was 24 ± 5.54 years. Six male patients (85.7%) and one female were included (14.3%). None of the patients had comorbidities. Four patients had primitive neuro-ectodermal tumors (57.1%) while three had osteogenic sarcomas (42.9%). All patients had the radial nerve preserved during onco-resection. The average gap between implant surgery and salvage with FFFs was 77.5 ± 49.024 months. The indications for salvage with the FFF were infection of implants (42.9%) and aseptic loosening (57.1%). The defects were located proximally in seven patients (85.7%) and mid-shaft in one patient (14.3%). Seven patients had adjuvant chemotherapy (85.7%), while two had neoadjuvant radiotherapy (28.6%). The defect length after debridement and implant removal was 13 ± 5.62 cm. The fibula head was incorporated in 57.1% of the flaps (n=4). For flap fixation dynamic compression plates was used in one patient (14.3%); number 20 cerclage wiring, prolene mesh, and ethibond was used in another patient (14.3%); K wires were used in four patients (57.1%); and ethibond in 1 patient (14.3%). Only one flap had a double venous anastomosis. Two patients underwent re-exploration of the anastomosis (57.1%), the only flap harvested with a skin paddle required debridement of the cutaneous component (14.3%), and one patient had wound dehiscence (14.3%). Six flaps survived (85.7%). Bone union was achieved at 17 ± 1.25 weeks on average. The average MSTS score was 74.9%. The average follow up was 59.57 ± 43.48 months. CONCLUSION: The FFF is a resourceful alternative for the management of a failed prosthesis after oncologic resection of the proximal and mid-humerus, especially with previously infected prosthetic material. Due to its anatomical shape and the vascularized nature of tissue, the FFF provides a long bone segment for humeral reconstruction.

A multicohort geometric deep learning study of age dependent cortical and subcortical morphologic interactions for fluid intelligence prediction

The relationship of human brain structure to cognitive function is complex, and how this relationship differs between childhood and adulthood is poorly understood. One strong hypothesis suggests the cognitive function of Fluid Intelligence (Gf) is dependent on prefrontal cortex and parietal cortex. In this work, we developed a novel graph convolutional neural networks (gCNNs) for the analysis of localized anatomic shape and prediction of Gf. Morphologic information of the cortical ribbons and subcortical structures was extracted from T1-weighted MRIs within two independent cohorts, the Adolescent Brain Cognitive Development Study (ABCD; age: 9.93 ± 0.62 years) of children and the Human Connectome Project (HCP; age: 28.81 ± 3.70 years). Prediction combining cortical and subcortical surfaces together yielded the highest accuracy of Gf for both ABCD (R = 0.314) and HCP datasets (R = 0.454), outperforming the state-of-the-art prediction of Gf from any other brain measures in the literature. Across both datasets, the morphology of the amygdala, hippocampus, and nucleus accumbens, along with temporal, parietal and cingulate cortex consistently drove the prediction of Gf, suggesting a significant reframing of the relationship between brain morphology and Gf to include systems involved with reward/aversion processing, judgment and decision-making, motivation, and emotion.

Regional left ventricle scar detection from routine cardiac computed tomography angiograms using latent space classification

Objectives:The aim of this study is to develop an automated method of regional scar detection on clinically standard computed tomography angiography (CTA) using encoder–decoder networks with latent space classification. Background:Localising scar in cardiac patients can assist in diagnosis and guide interventions. Magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) is the clinical gold standard for scar imaging; however, it is commonly contraindicated. CTA is an alternative imaging modality that has fewer contraindications and is widely used as a first-line imaging modality of cardiac applications. Methods:A dataset of 79 patients with both clinically indicated MRI LGE and subsequent CTA scans was used to train and validate networks to classify septal and lateral scar presence within short axis left ventricle slices. Two designs of encoder–decoder networks were compared, with one encoding anatomical shape in the latent space. Ground truth was established by segmenting scar in MRI LGE and registering this to the CTA images. Short axis slices were taken from the CTA, which served as the input to the networks. An independent external set of 22 cases (27% the size of the cross-validation set) was used to test the best network. Results:A network classifying lateral scar only achieved an area under ROC curve of 0.75, with a sensitivity of 0.79 and specificity of 0.62 on the independent test set. The results of septal scar classification were poor (AUC < 0.6) for all networks. This was likely due to a high class imbalance. The highest AUC network encoded anatomical shape information in the network latent space, indicating it was important for the successful classification of lateral scar. Conclusions:Automatic lateral wall scar detection can be performed from a routine cardiac CTA with reasonable accuracy, without any scar specific imaging. This requires only a single acquisition in the cardiac cycle. In a clinical setting, this could be useful for pre-procedure planning, especially where MRI is contraindicated. Further work with more septal scar present is warranted to improve the usefulness of this approach.

The Efficacy of Three Rotary Systems (Reciproc Blue, WaveOne Gold, and AF Blue R3) in Preparing Simulated, Highly Curved Root Canals: An In Vitro Study.

Purpose This study aimed to evaluate the effectiveness of three rotary, single-file, and reciprocating systems in terms of preparation time and canal centralization in simulated highly curved root canal preparation. Materials and methods The study sample consisted of 45 simulated canals with a curvature of 40°. They were randomly distributed into three experimental groups: Group 1-Reciproc Blue; Group 2-WaveOne Gold; and Group 3-AF Blue R3. A glide path was established by #10 hand K-file, then red dye was colored on the simulated canals, and photographs of the sample were taken before preparation. Then, the canals of each group were prepared, and other photographs were taken after preparation. The images of the two phases were combined using AutoCAD, where the canal was divided into three parts and the preparation area was measured from the right and left sides of each part of the canal. The preparation time for each system was also measured. Results While there were no statistically significant differences in the rate of preserving canal centralization in the middle and apical thirds between preparation groups, a statistically significant difference was found in the coronal third, as the Reciproc Blue and WaveOne Gold systems have a greater ability to maintain the centrality of the canal compared to the AF Blue R3 system. While there were no statistically significant differences between the Reciproc Blue and WaveOne Gold systems in the coronal third, as for the preparation time, it was found that there were statistically significant differences in the preparation time between the groups in favor of the WaveOne Gold system. Conclusion Both preparation systems (Reciproc Blue and WaveOne Gold) maintained the anatomical shape and canal centrality, with more cons for WaveOne Gold compared to the Reciproc Blue system. Regarding the volumetric changes, AF Blue R3 had the greatest changes compared to the Reciproc Blue and WaveOne Gold systems. WaveOne Gold Group, in terms of canal preparation time, showed the least time among the investigated groups.

Feasibility of a longitudinal statistical atlas model to study aortic growth in congenital heart disease

Abstract Background Studying anatomical shape progression over time is of utmost importance to refine our understanding of clinically relevant processes. These include vascular remodelling, such as aortic dilation, which is particularly important in some congenital heart defects (CHD). Purpose A novel methodological framework for analysing three-dimensional (3D) shape changes over time (“growth”) has been applied for the first time in a CHD scenario, i.e., bicuspid aortic valve (BAV) disease, the most common CHD. Methods Three-dimensional aortic shapes (n=94) reconstructed as surface meshes from cardiovascular magnetic resonance imaging (MRI) data represented the input for a longitudinal shape atlas model, using multiple scans over time (n=2–4 scans per patient). This model relies on diffeomorphic transformations in the absence of point-to-point correspondence, and on the correct combination of initialization, estimation, and registration parameters. Results We computed the 3D shape trajectory of an average disease progression over time in our cohort (Picture 1, grey to blue shapes), as well as time-dependent parameters, geometric variations and the average shape of the population (Picture 1, red shape). Results cover a spatiotemporal spectrum of visual and numerical information that can be further used to investigate clinical associations and stratify patients, as such capturing aortic remodelling in the presence of BAV aortopathy. Conclusion This proof-of-concept study demonstrates the feasibility of applying advanced statistical shape models to track disease progression and stratify patients with CHD. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): British Heart Foundation and NIHR BRC

The reasonable therapeutic modality for biliary duct-to-duct anastomotic stricture after liver transplantation: ERCP or PTC?

ObjectiveTo compare the initial success rate, feasibility, and effectiveness of endoscopic retrograde cholangiopancreatography (ERCP) versus percutaneous transhepatic cholangiography (PTC) for anastomotic biliary stricture after liver transplantation (LT).MethodsWe retrospectively analyzed the data collected during January 2015 to December 2021 from liver transplantation recipients who developed anastomotic biliary stricture after liver transplantation and treated by ERCP and/or PTC. The success rate, complications and patients’ survival rate of ERCP and PTC procedures was evaluated.ResultsForty-eight patients who underwent LT and were confirmed to have the anastomotic biliary stricture were enrolled. Overall, 48/48 patients underwent single or multiple ERCP procedures as the first line therapy; 121 therapeutic ERCPs (3.36 ± 2.53 ERCPs per patient) were performed in 36/48 patients successfully. All the 12 patients who failed ERCP tend to have special bile duct conditions such as overlong, angle shaped, and/or extremely narrowed bile duct and underwent PTC as an alternative treatment. The initial success rate of ERCP was 75% (36/48) while the success rate of ERCP for the 12 patients with special bile duct was 0% (0/12). PTC was an effective second-line treatment for those 12 patients who failed ERCP, and 58.33% (7 of 12 cases) were treated successfully. The average procedure time in PTC group was significantly lower than ERCP group (t=2.292, P=0.027). The feasibility of ERCP was associated with the anatomical shape of bile duct and the severity of the stricture site. Finally, the cumulative survival rate was 100% (12/12) in PTC group compared to 86.11% (31/36) in ERCP group (χ2 = 0.670, P=0.413).ConclusionERCP is the gold standard method for the diagnosis and effective intervention for the management of biliary complications after LT. However, its use in certain types of biliary complications (e.g., patients with severe anastomotic biliary stricture and those with overlong and angle shaped bile ducts) is not promising and associated with significant risk of complications. PTC and other interventions should be studied along with ERCP for patients for whom ERCP may not work. The feasibility and efficacy of primary management can be predicted by the noninvasive imaging examinations like Magnetic Resonance Cholangiopancreatography (MRCP) before the procedure, which may help with the choice of the most reasonable therapeutic modality and avoiding unnecessary financial burden and complications.