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We describe a novel approach for compressing truncated signed distance fields (TSDF) stored in 3D voxel grids, and their corresponding textures. To compress the TSDF, our method relies on a block-based neural network architecture trained end-to-end, achieving state-of-the-art rate-distortion trade-off. To prevent topological errors, we losslessly compress the signs of the TSDF, which also upper bounds the reconstruction error by the voxel size. To compress the corresponding texture, we designed a fast block-based UV parameterization, generating coherent texture maps that can be effectively compressed using existing video compression algorithms. We demonstrate the performance of our algorithms on two 4D performance capture datasets, reducing bitrate by 66% for the same distortion, or alternatively reducing the distortion by 50% for the same bitrate, compared to the state-of-the-art., Comment: Danhang Tang and Saurabh Singh have equal contribution

Nowadays, floating-point temporal-spatial datasets are routinely generated from scientific observational apparatuses or computer simulations at an unprecedented pace. The sheer amount of these large volumetric datasets on the order of terabytes or petabytes consume massive resources in terms of bandwidth, storage and computational power. On the other hand, scientists, equipped with low-end post-analysis machines, often find it impossible to visualize and analyze these massive datasets with such limited resources in hand, not to mention their ultimate goal of real time analysis and visualization. To solve this discrepancy, a compact data representation has to be generated and a trade-off between resource consumption and analytical precision has to be found. There are many existing volumetric representation generating methods, almost all of which adopts some kind of hand-engineered heuristics to extract the effective portion of the datasets. However, the trade-off between resource consumption and analytical quality could not be well established due to the introduction of hand-engineered heuristics. In this paper, we present a deep learning based method that can adaptively capture the inherently complicated dynamics of temporal-spatial volumetric datasets without introducing any hand engineered features. We train an autoencoder based neural network with quantization and adaptation. Compared with existing methods, our method could learn data representation at a much lower compressed/uncompressed rate while preserving the details of original datasets. Also, our method could adapt with different data distribution and conduct compression and decompression in real time. Through extensive experiments, we show the effectiveness and efficiency of our approach over existing methods.

The recent high core gains of 29% in laser fusion experiments at the LLE Rochester are evaluated and compared with related earlier measurements where surprisingly the self-similarity model for volume compression provides a common description. This is a proof that the isentropic conditions of stagnation-free compression were mostly fulfilled at the optimized experimental gains, in contrast to highly entropy-producing shock and central spark conditions. Some projections are given of how these results may be generalized to volume ignition for the parameters of the NIF (National Ignition Facility). The proof of stagnation-free volume compression for the best laser fusion gains indicates the advantages of volume ignition, which not only is ‘robust’ and simply follows the natural adiabatic compression, but also is much less sensitive to instabilities and mixing. However, its essential advantage is that it is free from symmetry problems – in contrast to spark ignition, with its spherical detonation front.

This paper presents a test slice difference (TSD) technique to improve test data compression. It is an efficient method and only needs one scan cell. Consequently, hardware overhead is much lower than cyclical scan chains (CSR). As the complexity of VLSI continues to grow, excessive power supply noise has become seriously. We propose a new compression scheme which smooth down the switching activity and reduce the test data volume simultaneously.

Based on first-principles calculations, we predict a substantial increase in the optical dielectric function of LiAsSe$_2$ under pressure. We find that the optical dielectric constant is enhanced threefold under volume compression. This enhancement is mainly due to the dimerization strength reduction of the one-dimensional (1D) As--Se chains in LiAsSe$_2$, which significantly alters the wavefunction phase mismatch between two neighboring chains and changes the transition intensity. By developing a tight-binding model of the interacting 1D chains, the essential features of the low-energy electronic structure of LiAsSe$_2$ are captured. Our findings are important for understanding the fundamental physics of LiAsSe$_2$ and provide a feasible way to enhance the material optical response that can be applied to light harvesting for energy applications., Comment: 13 pages, 6 figures

Volume data sets are becoming increasingly large and numerous with advances in acquisition methods and in computers. To date, the most commonly used lossless compression software for volume data sets are Lempel-Ziv-based applications designed for text compression. We present an improved lossless volume compression algorithm based on Lempel-Ziv '77.

Compression and decompression of volume data is gaining increasing importance, especially with wide use of volume visualization techniques in distributed environments. Hitherto researchers have used direct extensions of still- image and video compression techniques to volume data, but these are associated with limitations of scalar quantization. We present an orientation band (ORB) technique for volume compression that exploits orientation information, and consequently preserves structure within the data. The ORB scheme uses a hybrid of lossless (pyramidal) and lossy (vector quantized) techniques to compress within user-specified space and error bounds. The resulting compressed volumes are suited for progressive network transmission and for fast volume rendering.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Volume data such as those acquired by magnetic resonance imaging techniques can be compressed efficiently using the wavelet transform. Wavelet compression methods need to retain both the value and the location of the significant coefficients. We present experimental results demonstrating the use of zerotree encoding methods in wavelet compression can enhance the ability to further compress volume data.

This research explores the principles, implementation, and optimization of a competitive volume compression system based on fractal image compression. The extension of fractal image compression to volumetric data is trivial in theory. However, the simple addition of a dimension to existing fractal image compression algorithms results in infeasible compression times and noncompetitive volume compression results. This paper extends several fractal image compression enhancements to perform properly and efficiently on volumetric data, and introduces a new 3D edge classification scheme based on principal component analysis. Numerous experiments over the many parameters of fractal volume compression suggest aggressive settings of its system parameters. At this peak efficiency, fractal volume compression surpasses vector quantization and approaches within 1 dB PSNR of the discrete cosine transform. When compared to the DCT, fractal volume compression represents surfaces in volumes exceptionally well at high compression rates, and the artifacts of its compression error appear as noise instead of deceptive smoothing or distracting ringing.

Objective The purpose of this study was to develop a new biomechanical index for assessing the elastic characteristics of carotid plaques and to test the association between carotid plaque elasticity and ischemic cerebrovascular events (ICEs). Methods One hundred and eighteen carotid plaques were detected with real-time three-dimensional ultrasonography in 104 patients. All patients received MRI and were divided into two groups according to the history of ICEs: patients with ICEs (n = 58, including 20 patients with transient ischemic attack and 38 with ischemic stroke) and patients without ICEs (n = 46). The carotid plaque volume at end diastole (Vd) and end systole (Vs) was measured by use of a TomTec (Munich, Germany) workstation. Plaque volume compression ratio (VCR) was calculated as (Vd - Vs)/ Vd X 100 and the reproducibility of VCR measurement was analyzed. The carotid intima-media thickness, plaque area and plaque acoustic density were also measured. Multivariate logistic regression was used to test the association between ICEs and plaque ultrasonic parameters or traditional risk factors including age, sex, smoking, blood pressure, history of coronary heart disease, levels of serum low-density lipoprotein, triglyceride and glucose. Results Satisfactory images of carotid plaques were obtained in all patients by real-time three-dimensional ultrasonography. Patients with ICEs and patients without ICEs differed significantly in VCR (22.19 ± 8.42 vs. 13.95 ± 7.86, P

The paper specifies a novel coder/decoder that compresses sequences of 3D texture data to support the haptic rendering of animated volumes. Lossy compression gives 25% of the original size. Lossy compression and clipping gives 3% but requires the renderer to query for new data when the point of contact moves. We evaluated the codec by means of rendering volumes on a 3-DOF Phantom 1.5A that simulated viscosity for each texture element. In this setting, we studied the impact of information loss in controlled experiments. We validated that our codec preserves haptic perception. An area of application is the development of network-distributed virtual environments that generate visual and haptic feedback

BACKGROUND: Three-dimensional ultrasound images allow virtual sonography even at a distance. However, the size of final 3-D files limits their transmission through slow networks such as the Internet. OBJECTIVE: To analyze compression techniques that transform ultrasound images into small 3-D volumes that can be transmitted through the Internet without loss of relevant medical information. METHODS: Samples were selected from ultrasound examinations performed during, 1999-2000, in the Obstetrics and Gynecology Department at the University Hospital in La Laguna, Canary Islands, Spain. The conventional ultrasound video output was recorded at 25 fps (frames per second) on a PC, producing 100- to 120-MB files (for from 500 to 550 frames). Processing to obtain 3-D images progressively reduced file size. RESULTS: The original frames passed through different compression stages: selecting the region of interest, rendering techniques, and compression for storage. Final 3-D volumes reached 1:25 compression rates (1.5- to 2-MB files). Those volumes need 7 to 8 minutes to be transmitted through the Internet at a mean data throughput of 6.6 Kbytes per second. At the receiving site, virtual sonography is possible using orthogonal projections or oblique cuts. CONCLUSIONS: Modern volume-rendering techniques allowed distant virtual sonography through the Internet. This is the result of their efficient data compression that maintains its attractiveness as a main criterion for distant diagnosis. [J Med Internet Res 2001;3(2):e21]

Scientific simulations on high-performance computing (HPC) systems can generate large amounts of floating-point data per run. As compared to lossless compressors, lossy compressors, such as SZ and ZFP, can reduce data volume more aggressively while maintaining the usefulness of the data. However, a reduction ratio of more than two orders of magnitude is almost impossible without seriously distorting the data. In deep learning, the autoencoder has shown potential for data compression. Whether the autoencoder can deliver similar performance on scientific data, however, is unknown. In this paper, we for the first time conduct a comprehensive study on the use of autoencoders to compress real-world scientific data and illustrate several key findings on using autoencoders for scientific data reduction. We implement an autoencoder-based compression prototype to reduce floating-point data. Our study shows that the out-of-the-box implementation needs to be further tuned in order to achieve high compression ratios and satisfactory error bounds. Our evaluation results show that, for most test datasets, the tuned autoencoder outperforms SZ by 2 to 4X, and ZFP by 10 to 50X in compression ratios, respectively. Our practices and lessons learned in this work can direct future optimizations for using autoencoders to compress scientific data.

Background: The relationship between anterior cruciate ligament (ACL) injury and anatomical structures is still a topic of debate. Purpose: The aim of this study was to compare knee geometry in demographically matched ACL-injured and ACL-intact athletes. Methods: We conducted a case-control study comparing 2 groups, each consisting of 55 professional athletes (44 men and 11 women): 1 group with complete ACL tears (cases) and 1 group with intact ACLs (controls). The groups were compared using magnetic resonance imaging (MRI) in terms of intercondylar notch geometry, tibial plateau characteristics, and ACL volume. Results: Among cases and controls, we found the cases had lower notch width (20.24 ± 2.68 mm vs. 22.04 ± 2.56 mm, respectively) and notch width index (0.29 ± 0.03 vs. 0.31 ± 0.03, respectively). The mean ACL volume in the cases (1181.63 mm3 ± 326 mm3) was also lower than in controls (1352.61 mm3 ± 279.84 mm3). The parameters of tibial slope geometry were comparable between groups. In addition, women had lower ACL volume than men (1254 ± 310 mm3 vs. 890 ± 267 mm3, respectively) and higher medial posterior tibial slope (4.76 ± 2.6 vs. 6.63 ± 1.83, respectively). Among cases, women had narrower notch width than men (16.9 ± 2.42 mm vs. 21.08 ± 2.03 mm). However, notch width index was comparable between male (0.3 ± 0.02) and female (0.28 ± 0.03) cases. Conclusion: Our findings suggest that narrow notch width and low ACL volume may enhance the risk of ACL injury among athletes. There was no association found between posterior tibial slope and ACL injury between athletes with injured ACLs and controls. Further study is indicated.

Background The majority of fetal structural defects can be detected in the second trimester, thus this is the main time for screening for structural defects. 3D imaging of the fetal brain does not create a common part of this screening. Methods This prospective observational study was conducted at the Fetal Medicine Center of The Gynecological-Obstetrical Department of the University Hospital Olomouc in years 2017- 2020. The study sample was 451 consecutively scanned morphologically normal fetuses attending for routine second trimester anatomical survey at 20-22 weeks of pregnancy. A transabdominal 3D ultrasound volume acquisition of fetal brain was obtained from an axial and sagittal plane using skull sutures as an acoustic window. Results Both the corpus callosum (CC) and the vermis (VC) were detected in 51.7% of examinations in the sagittal plane, and in 31.7% in the axial plane. In 61.9% of the examinations, there was at least partial detection in both planes. Maternal BMI was found to be the only significant predictor of the quality of imaging in both planes. Conclusion 3D acquisition of fetal brain images in the sagittal plane followed by manipulation of acquired volume was valuable in assessment of corpus callosum and cerebellar vermis. This allows reconstruction of the sagittal plane that can be difficult to obtain in 2D imaging.

Background: Tumor regression grade (TRG) correlates with prognosis in patients with locally advanced rectal cancer (LARC), but there is controversy regarding the use of magnetic resonance imaging (MRI) for determining TRG. This study to evaluate the diagnostic value of change rate in signal intensity (SI) and volume (V) from MRI to TRG following preoperative chemoradiotherapy (CRT) in patiens with LARC.Materials and methods: This retrospective analysis examined 82 LARC patients who were admitted to our institution between Oct 2017 and Oct 2019. Patients underwent pre- and post-CRT T2-weighted (T2W), diffusion-weighted (DW)/apparent diffusion coefficient (ADC), and contrast-enhanced T1-weighted (ceT1W) MRI. Change rate of volume and relative SI ratio(%△V and %△SIR) from each sequence were determined. All LARCs were confirmed pathologically and classified into TRG 0, 1, 2 and 3. Descriptive statistics and receiver operating characteristic (ROC) analysis, with calculation of area under the curve (AUC), were used to compare the diagnostic performances. Results: Sixteen patients had TRG-0, 15 had TRG-1, 35 had TRG-2, and 16 had TRG-3. Except for ADC-%△SIR, the remaining%△V and %△SIR on T1W, DWI, and ceT1W had significant differences among the four groups. %△V and/or %△SIR did not distinguish TRG-1 from TRG-2 nor TRG-2 from TRG-3, but differences between other TRGs were identified by %△V and/or %△SIR on T2W, DWI, and ceT1W. The combined use of DW-%△V and T2W-%△SIR provided the best diagnostic performance in distinguishing of TRG-0 from TRG-2 (AUC: 0.954) and from TRG-3 (AUC: 1.000).Conclusions: Preoperative MRI of LARC patients can determine TRG and may improve selection of the preoperative therapy.

Statement of problem The anatomic complexity of the ear challenges conventional maxillofacial prosthetic rehabilitation. The introduction of specialized scanning hardware integrated into computer-aided design and computer-aided manufacturing (CAD-CAM) workflows has mitigated these challenges. Currently, the scanning hardware required for digital data acquisition is expensive and not readily available for prosthodontists in developing regions. Purpose The purpose of this virtual analysis study was to compare the accuracy and precision of 3-dimensional (3D) ear models generated by scanning gypsum casts with a smartphone camera and a desktop laser scanner. Material and methods Six ear casts were fabricated from green dental gypsum and scanned with a laser scanner. The resultant 3D models were exported as standard tessellation language (STL) files. A stereophotogrammetry system was fabricated by using a motorized turntable and an automated microcontroller photograph capturing interface. A total of 48 images were captured from 2 angles on the arc (20 degrees and 40 degrees from the base of the turntable) with an image overlap of 15 degrees, controlled by a stepper motor. Ear 1 was placed on the turntable and captured 5 times with smartphone 1 and tested for precision. Then, ears 1 to 6 were scanned once with a laser scanner and with smartphones 1 and 2. The images were converted into 3D casts and compared for accuracy against their laser scanned counterparts for surface area, volume, interpoint mismatches, and spatial overlap. Acceptability thresholds were set at 0.70 for spatial overlap. Results The test for smartphone precision in comparison with that of the laser scanner showed a difference in surface area of 774.22 ±295.27 mm2 (6.9% less area) and in volume of 4228.60 ±2276.89 mm3 (13.4% more volume). Both acceptability thresholds were also met. The test for accuracy among smartphones 1, 2, and the laser scanner showed no statistically significant differences (P>.05) in all 4 parameters among the groups while also meeting both acceptability thresholds. Conclusions Smartphone cameras used to capture 48 overlapping gypsum cast ear images in a controlled environment generated 3D models parametrically similar to those produced by standard laser scanners.

The topics of sub-specialization and regionalization of care have garnered increased attention among pediatric surgeons. Thyroid surgeries are one such sub-specialty and are commonly concentrated within practices. A national survey was conducted examining current surgeon practices and beliefs surrounding pediatric thyroid surgery.Non-resident members of the American Pediatric Surgical Association (APSA) were surveyed in October 2020. Respondents were stratified based on self-reported thyroid surgical experience. Those who performed thyroid surgery were asked about surgical technique and operative practices; those who did not were asked about referral patterns. All respondents were asked about perceptions surrounding the volume-outcome relationship for pediatric thyroid surgery.Among 1015 APSA members, 405 (40%) responded, with 79% (317/400) practicing at academic hospitals, 58% (232/401) practicing in major metropolitan area, and 41% (161/392) with over 10 years of attending pediatric surgery experience. Most respondents (88%, n = 356) agreed that thyroid surgery volume affects outcome, though wide variation was reported in the annual case threshold for "high volume" surgery. Eighty-four respondents (21%) reported performing ≥ 1 pediatric thyroid surgery in the past year. Of these, 82% routinely use recurrent laryngeal nerve monitoring, 32% routinely send hemithyroidectomy patients home the same day, and there was little consensus surrounding postoperative hypocalcemia management. The majority of respondents endorse performing thyroid procedures with a colleague.Pediatric thyroid surgery appears to be performed by a subset of active pediatric surgeons, most of whom endorse the use of a dual operating team. More evidence is needed to build consensus around additional perioperative practices.

Objective : To evaluate, by means of cone beam computed tomography (CBCT), the volume change of maxillary sinuses in patients that underwent orthodontic maxillary posterior en masse intrusion anchored with miniplates. Materials and Methods : The sample consisted of pretreatment (T1) and posttreatment (T2) CBCT scans obtained from 14 patients (4 male and 10 female), with a mean age of 32.4 years, that underwent orthodontic maxillary posterior en masse intrusion anchored with miniplates in the zygomatic crest. The mean treatment duration was 20 months and the mean intrusion movement was 2.4 mm. Maxillary sinus volume was measured by means of the software ITK SNAP (version 3.8.0) in T1 and T2 CBCT scans. The changes in sinuses volume were calculated by T1-T2 values. Data were analyzed statistically with Wilcoxon test at 5% of level of significance and the method error was analyzed with Wilcoxon test, intraclass correlation and Dahlberg's formula. Results : The mean difference (T1-T2) was -242.85 mm³ (p = 0.396) for the right sinus and -32.5 mm³ (p = 0.875) for the left sinus. A slight increase in the volume of the sinuses was shown although these results were not statistically significant. Conclusion : The orthodontic maxillary posterior en masse intrusion anchored with miniplates did not influence significantly the maxillary sinus volume.

In this paper, a new data augmentation algorithm, named Mask2Defect is proposed. Via prior knowledge based data infusing, this method is able to generate defects with varied features. Large volume of defects with different shapes, severities, scales, rotation angles, spatial locations, and part numbers can be generated in a controllable manner. These generated defects will work as teacher samples to fine-tune the inspection model, and automatically adapt it to a wider range of defects. To be specific, we first encode the prior knowledge into the teacher mask via the Industrial Prior Knowledge Encoder, and render the defect details according to the mask with the Mask-to-Defect Construction Network. Then, the Fake-to-Real Domain Transformation GAN is used to transform the rendered samples from the fake domain into the real defect domain. Experiments reveal that the synthesized image quality of our method outperforms the state-of-the-art generative methods, and the performance of the inspection model in defect classification and localization has also been improved by fine-tuned with the generated samples.

Objectives This study aimed to determine the correlation between alveolar cleft volume and fenestration and dehiscence in the adjacent alveolar bone in patients with unilateral cleft lip and palate (UCLP) using cone-beam computed tomography (CBCT) sections. Materials and methods In this descriptive, cross-sectional study, CBCT scans of 68 non-syndromic patients with UCLP aged between 6 and14 years were selected. All patients were treated in Iran and had undergone lip and palate repair surgery within the first 3 to 18 months after birth. CBCT scans had been taken after orthodontic expansion and prior to alveolar bone grafting surgery. Cleft volume, fenestration and dehiscence were assessed using Mimics software. Data were analyzed using independent t-test, Kruskal-Wallis test, Spearman's correlation coefficient and logistic regression model. Results The mean alveolar cleft volume was 628.66±172.84 mm3. There was a significant negative correlation between cleft volume and fenestration (P Conclusion The Mimics software can be successfully used to estimate the cleft volume prior to surgical procedures in UCLP patients. The results suggest that the alveolar cleft volume can be used as an aid to assess the periodontal condition of adjacent teeth. The cleft volume has a negative and positive correlation with fenestration and dehiscence respectively.

Background The association between volume and outcomes has led to recommendations that patients undergo surgery at high-volume centers. We aimed to determine if older patients with rectal cancer are undergoing operations at high-volume centers. Methods We identified patients ≥50 years old who underwent rectal cancer resection using the NCDB (2004–2015). Tertiles were used to categorize facility volume and distance traveled. Results Higher facility volume was associated with improved outcomes. Patients >75 years old were less likely than patients 50–59 years old to be treated at high-volume centers. Traveling >16.8 miles was associated with treatment at high-volume facilities, however patients >75 years old were less likely to travel >16.8 miles. Conclusions Higher facility volume is associated with improved outcomes after rectal cancer resection. However, older patients are less likely to be treated at high-volume facilities. Older patients travel shorter distances for care, suggesting that care integration across networks must be optimized.

We present a user-initialized, automated segmentation method for use with echocardiograms (echo). The method uses an iterative Dijkstra's algorithm, a strategic node selection, and a novel cost matrix formulation based on intensity peak prominence, termed the Prominence Iterative Dijkstras algorithm, or ProID. ProID is initialized with three user-input clicks per time-series scan. ProID was tested using artificial echo images representing five different systems. Results showed accurate LV contours and volume estimations as compared to the ground-truth for all systems. Using the CAMUS dataset, we demonstrate ProID maintained similar Dice similarity scores to other automated methods. ProID was then used to analyze a clinical cohort of 66 pediatric patients, including normal and diseased hearts. Output segmentations, end-diastolic, end-systolic volumes, and ejection fraction were compared against manual segmentations from two expert readers. ProID maintained an average Dice score of 0.93 when comparing against manual segmentation. Comparing the two expert readers, the manual segmentations maintained a score of 0.93 which increased to 0.95 when they used ProID. Thus, ProID reduced the inter-operator variability across the expert readers. Overall, this work demonstrates ProID yields accurate boundaries across age groups, disease states, and echo platforms with low computational cost and no need for training data.

Background Given the complexity of living donor hepatectomy, it is expected that high hospital volume will better outcomes. This study aims to evaluate post-operative outcomes for living donor hepatectomy in a medium volume liver transplant centre and compare to outcomes in high volume centres. Also, it serves as a validation tool for framework of structure-process-outcome model for safe living donor hepatectomy program. Methods 204 donors who underwent donor hepatectomy between June 1996 to September 2019 were reviewed retrospectively and compared to outcomes in high volume centres. Results At 6 months, overall donor morbidity rate was 20/204 (9.8%). Wound complications were most common at 5/204 (2.5%). Majority of complications were either Clavien grade 1 or 2 and only 3 donors had Clavien grade 3 complications. There was zero donor mortality. Discussion Our centre's donor morbidity rate of 9.8% is the one of the lowest reported in the published literature. With increased experience, stringent donor selection and enhanced perioperative care by a multi-disciplinary team, outcomes in a medium volume centre can match the outcomes reported in high volume centres. The framework for quality in terms of structure, process and outcomes is presented which can be adopted for developing programs.

Introduction This study aims to define the impact that the novel Coronavirus Disease 2019 (COVID-19) pandemic has had on the volume of common plastic and reconstructive procedures. Methods TrinetX is a national, federated database that was utilitzed in surveying plastic and reconstructive procedural volumes among 53 Healthcare organizations (HCO) between March 2018 and May 2021. This timeframe was divided into pre-pandemic (March 2018 to February 2020) and pandemic periods (March 2020 to May 2021). Each period was then sub-divided into the four seasons of the year and mean monthly procedural volume per HCO was compared. A student's t-tests comparing pre-pandemic and pandemic seasonal mean procedural volumes were used for statistical analysis. Results A total of 366,032 patient encounters among 53 HCO were included. The average seasonal volume per HCO of all procedures decreased from 872.11 procedures during pre-pandemic seasons to 827.36 during pandemic seasons. Spring 2020 volumes declined for most procedures as 15 of 24 (63%) assessed procedure categories experienced statistically significant decreases. Spring 2021 experienced rebounds with 15 of 24 (63%) assessed procedures showing statistically significant increases. Conclusion During the pandemic period, the average procedural volume per HCO of 14 procedure categories was significantly less than the pre-pandemic average procedural volume. As a whole, there was a inverse relationship between new United States COVID-19 cases and plastic and reconstructive surgery procedure volumes.

Background: Manual segment target volumes were time-consuming and inter-observer variability couldn’t be avoided. With the development of computer science, auto-segmentation had the potential to solve this problem. Objective: To evaluate the accuracy and stability of Atlas-based and deep-learning-based auto-segmentation of the intermediate risk clinical target volume, composed of CTV2 and CTVnd, for nasopharyngeal carcinoma quantitatively. Methods and Materials: A cascade-deep-residual neural network was constructed to automatically segment CTV2 and CTVnd by deep learning method. Meanwhile, a commercially available software was used to automatically segment the same regions by Atlas-based method. The datasets included contrast computed tomography scans from 102 patients. For each patient, the two regions were manually delineated by one experienced physician. The similarity between the two auto-segmentation methods was quantitatively evaluated by Dice similarity coefficient, the 95th Hausdorff distance, volume overlap error and relative volume difference, respectively. Statistical analyses were performed using the ranked Wilcoxon test. Results: The average Dice similarity coefficient (±standard deviation) given by the deep-learning- based and Atlas-based auto-segmentation were 0.84(±0.03) and 0.74(±0.04) for CTV2, 0.79(±0.02) and 0.68(±0.03) for CTVnd, respectively. For the 95th Hausdorff distance, the corresponding values were 6.30±3.55 mm and 9.34±3.39 mm for CTV2, 7.09±2.27 mm and 14.33±3.98 mm for CTVnd. Besides, volume overlap error and relative volume difference could also predict the same situations. Statistical analyses showed significant difference between the two auto-segmentation methods (p Conclusions: Compared with the Atlas-based segmentation approach, the deep-learning-based segmentation method performed better both in accuracy and stability for meaningful anatomical areas other than organs at risk.

PURPOSE To investigate the volumetric facial soft tissue changes associated with wearing complete dentures using 3D face scans. MATERIALS AND METHODS Forty volunteers, 20 men and 20 women, were recruited for the study and treated with maxillary and mandibular complete dentures. Six facial scans were taken of each subject. Three scans were wearing a complete denture, and three without them. The 3D face scans were captured with the volunteers in three mouth positions: closed, relaxed, and smiling. Each scan was superimposed in order to analyze and quantify the linear measurements of 14 soft tissue landmarks and the total volume that the subject gained with the prosthesis. RESULTS Three variables were evaluated in each analysis: gender, mouth attitude, and age category. In the analysis of the soft tissue landmarks, there was a significant effect of age, with patients older than 75 years showing the greatest changes (P < .05). The landmarks that showed the most changes were those located around the mouth. In the volume analysis, the variable with the highest influence was gender, with men gaining more volume than women (P < .05). CONCLUSION Complete dentures have a significant effect on volumetric change in perioral tissues. These changes are marked in patients older than 75 years. Compared to women, men depicted greater volumetric changes with complete dentures. These results open a new avenue for clinicians and developers using face scans to design future restorations for edentulous patients.

Urinary bladder volume monitoring can benefit from contactless measurements, as alternative to the traditional medical methods of transurethral catheterization or ultrasound examination. The emerging modality of Magnetic Induction Tomography (MIT) offers the possibility for estimation of the intravesical volume in the physiological and pathological states using conductivity map reconstructions of the tissues present in the pelvic region. Within MIT, eddy currents originating from the conductive urine can produce their own magnetic field in response to an external magnetic source that is susceptible of being detected outside the body by means of a static ring of sensing coils. However, the ill-conditioned and ill-posed nature of the MIT Inverse Problem make the numerical implementation and conductivity estimation highly laborious. In this paper, we present a rotational frame model based on the MIT principles with application in urodynamic studies, which allows to extend the number of contactless measurements without increasing the overall dimension of the simulation domain, at the expense of solving multiple MIT Forward Problems. On the inversion process, the single-step Gauss-Newton method with Laplacian regularizer is recruited to estimate the bladder volume non-invasively and remotely (estimation error of 19%) using a simplified (quasi 2D) approximation to the distribution of eddy currents in the examined region, therefore paving the way for this technique to surpass the current limitations found in intravesical volume monitoring.

Three-dimensional ultrasound (US) of abdominal aortic aneurysms (AAAs) is limited by the field-of-view of the 3D-US transducer. To obtain an extended field-of-view (XFoV), two transducer navigation system-assisted US protocols have been developed: XFoV-2D and XFoV-3D. In this study, the XFoV US protocols were compared with the currently available 3D-US protocol with standard field-of-view (FoV-st) and the established gold standard, computed tomography angiography (CTA). A total of 65 patients with AAA were included, and AAA imaging was processed offline with prototype software. The novel XFoV-2D and XFoV-3D protocols allowed for assessment of full AAA volume in significantly more patients (45/65 [69%] and 43/65 [66%], respectively), compared with the current 3D-US standard, FoV-st (30/65 [46%] patients). The mean difference in AAA volume estimation between each XFoV US protocol and 3-D CTA differed significantly (XFoV-2D: 16.9 mL, XFoV-3D: 7.6 mL, p = 0.002), indicating that XFoV-3D agreed best with 3D-CTA. No significant difference was found in the variance of full AAA volume quantification between each XFoV US protocol and CTA (p = 0.49). It is concluded that the XFoV US protocols improved the generation of full AAA volumes compared with the currently available 3D-US technology, with AAA volume estimates comparable to CTA estimates.

Objective: The aim of this study is to investigate the effect of complex decongestive physiotherapy (CDP) plus intermittent pneumatic compression (IPC) applications on upper extremity circumference and volume in patients with lipedema. Methods and Results: All participants included in the study were included in a treatment protocol consisting of CDP and IPC. The Perometer 400 NT was used in the measurement of upper extremity volume and circumference before and after treatment. The measurements were performed in four reference points. According to the Perometer results before and after CDP, statistically significant reduction was found in the circumference of 3 of the 4 points of measurements performed in each of the left and right upper extremities. When the volume assessments were compared, it was seen that statistically significant reduction was found in the volume of both limbs. Conclusion: A treatment program consisting of CDP and IPC can be effective in reducing the circumference and volume of the arm in patients with upper extremity lipedema. So, CDP applications can help prevent the development of complications such as lipolymphedema, hypertension, and heart failure. Clinical Trial Registration number: NCT04643392 https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S000AF9B&selectaction=Edit&uid=U00055NT&ts=2&cx=-3oevdw.

Background: Lymphedema (LE) is a significant clinical problem for breast cancer survivors. While the water displacement test and circumferential assessment using a tape measure (TM) are common methods to assess differences in arm volumes, faster and more reliable methods are needed. Study purposes, in breast cancer survivors (n = 294), were to compare the average total arm volumes and interlimb volume ratios for women with and without a history of LE, using a TM and three-dimensional (3D), whole-body surface scanner (3D scan); compare the level of agreement between arm volumes and interlimb volume ratios obtained using the two devices; and evaluate the percent agreement between the two measures in classifying cases of LE using three accepted thresholds. Methods and Results: Measurements were done using a spring-loaded TM and Fit3D ProScanner. Paired t-tests and Bland-Altman analyses were used to achieve the study aims. For circumference and volume comparisons, compared with the 3D scan, values obtained using the TM were consistently smaller. In terms of level of agreement, the Bland-Altman analyses demonstrated large biases and wide limits of agreement for the calculated arm volumes and volume ratios. In terms of the classification of caseness, using the 200-mL interlimb volume difference criterion resulted in 81.6% overall agreement; using the >10% volume difference between the affected and unaffected arms resulted in 78.5% overall agreement; and using the volume ratio ≥1.04 criterion resulted in 62.5% overall agreement. For all three accepted threshold criteria, the percentage of cases was significantly different between the TM and 3D scan techniques. Conclusions: The 3D technology evaluated in this study has the potential to be used for self-initiated surveillance for LE. With improvements in landmark identification and software modifications, it is possible that accurate and reliable total arm volumes can be calculated and used for early detection.

Modern advanced phasor measurement units are developed with ultrahigh reporting rates to meet the demand for monitoring the power systems dynamics in detail. Due to the large volume of data, the communication and storage systems are seriously challenged with the presence of ultrahigh-density (UHD) synchrophasor and point-on-wave (POW) data. Therefore, it is an urgent task to compress the UHD data for more efficient communication and data storage. This article proposes several methods to compress the synchrophasor and POW data in a lossless manner. First, an improved time-series special compression (ITSSC) method is proposed to compress the UHD frequency data. Second, a delta-difference Huffman method is combined with the time-series special compression algorithm to compress the UHD phase angle data. Finally, a cyclical high-order delta modulation method is proposed to compress the UHD POW data. The proposed models are extensively tested and compared with different existing lossless compression algorithms using the field-collected synchrophasor and POW data at different reporting rates. The results indicate that the proposed algorithms are efficient in performing lossless compression for the UHD synchrophasor and POW data in real time.

OBJECTIVE The optimal treatment paradigm for large arteriovenous malformations (AVMs) is controversial. One approach is volume-staged stereotactic radiosurgery (VS-SRS). The authors previously reported efficacy of VS-SRS for large AVMs in a multiinstitutional cohort; here they focus on risk of symptomatic adverse radiation effects (AREs). METHODS This is a multicentered retrospective review of patients treated with a planned prospective volume staging approach to stereotactically treat the entire nidus of an AVM, with volume stages separated by intervals of 3–6 months. A total of 9 radiosurgical centers treated 257 patients with VS-SRS between 1991 and 2016. The authors evaluated permanent, transient, and total ARE events that were symptomatic. RESULTS Patients received 2–4 total volume stages. The median age was 33 years at the time of the first SRS volume stage, and the median follow-up was 5.7 years after VS-SRS. The median total AVM nidus volume was 23.25 cm3 (range 7.7–94.4 cm3), with a median margin dose per stage of 17 Gy (range 12–20 Gy). A total of 64 patients (25%) experienced an ARE, of which 19 were permanent. Rather than volume, maximal linear dimension in the Z (craniocaudal) dimension was associated with toxicity; a threshold length of 3.28 cm was associated with an ARE, with a 72.5% sensitivity and a 58.3% specificity. In addition, parietal lobe involvement for superficial lesions and temporal lobe involvement for deep lesions were associated with an ARE. CONCLUSIONS Size remains the dominant predictor of toxicity following SRS, but overall rates of AREs were lower than anticipated based on baseline features, suggesting that dose and size were relatively dissociated through volume staging. Further techniques need to be assessed to optimize outcomes.

Classification algorithms face difficulties when one or more classes have limited training data. We are particularly interested in classification trees, due to their interpretability and flexibilit...

A new correction method for laser Doppler velocimetry (LDV) measurement volume effects on the time-averaged velocity statistics is proposed by considering the probability density function of streamwise fluctuating velocity and the streamwise cross-sectional area of the measurement volume. The proposed correction method is fundamentally different from previous correction methods using a laser intensity profile of LDV. We propose a simple equation to correct the measurement volume effects. By using the equation and calculating both measurement locations and volumes precisely, the correction for the measurement volume effects on time-averaged velocity statistics can be performed on the basis of LDV measurement data. By comparing with the correction method proposed by Durst et al. (1995), the two correction methods provide almost the same results. In addition, the validity and applicability to high Reynolds numbers or low spatial resolution conditions of the two correction methods are confirmed.

PURPOSE To investigate the accuracy of a segment-counting method in predicting lung function and volume after stapler-based thoracoscopic segmentectomy in comparison with lobectomy. METHODS Between 2014 and 2018, patients who underwent these procedures were retrospectively reviewed. Thoracic computed tomography and spirometry data before and 1 year after the surgery were assessed. We evaluated the differences between the predicted values using a segment-counting method and the actual postoperative values for lung function and volume in each group. Sub-analyses were also performed to assess the impact of the number of staples and resected segments in predicting patient outcomes. RESULTS We included 116 patients (segmentectomy, 69; lobectomy, 47). Actual postoperative lung function and volume values matched the predicted values in the stapler-based segmentectomy group, and significantly exceeded the predictions in the lobectomy group (P

Background Studies of the hospital volume-outcome relationship have highlighted that a greater volume activity improves patient outcomes. While this finding has been known for years, most studies to date have failed to delve into what underlies this relationship. Objective This study aimed to shed light on the basis of the hospital volume effect on patient outcomes by comparing treatment modalities for epithelial ovarian carcinoma patients. Data An exhaustive dataset of 355 patients in first-line treatment for Epithelial Ovarian Carcinoma (EOC) in 2012 in three regions of France was used. These regions account for 15% of the metropolitan French population. Methods In the presence of endogeneity induced by a reverse causality between hospital volume and patient outcomes, we used an instrumental variable approach. Hospital volume of activity was instrumented by the distance from patients’ homes to their hospital, the population density, and the median net income of patient municipalities. Results Based on our parameter estimates, we found that the rate of complete tumor resection would increase by 15.5 percentage points with centralized care, and by 8.3 percentage points if treatment decisions were coordinated by high-volume centers compared to decentralized care. Conclusion As volume alone is an imperfect correlate of quality, policy-makers need to know what volume is a proxy for in order to devise volume-based policies.

The digitisation of heritage is being rapidly realised in many parts of the world thanks to LiDAR technology. In addition to the simple digital preservation of heritage, 3D acquisition makes it possible to monitor the structural condition and assess possible damage. This paper presents a method for modelling the lost volume of a heritage bridge. The selected case study is the Fillaboa bridge, in Salvaterra de Miño, Spain, which has two cutwaters with the same cutting angle, one of which is damaged and has a stone loss. The bridge was acquired with a Terrestrial Laser Scanner. The method consists of the following processes. First, the walls of the whole cutwater are segmented and aligned by Iterative Closest Point algorithm over the damaged cutwater. Second, the distance between the two point clouds is calculated and the damaged area is delimited in both point clouds. And third, the alpha shape algorithm is applied to model the point cloud of the damaged area to a polygon. By searching for the optimal alpha radius, the polygon that best fits the damaged volume is generated. The proposed method also allows digital reconstruction of the damaged area, although it is sensitive to acquisition problems, which require manual interventions in the processing. The accuracy of the method is mainly dependent on the acquired point cloud registration (with an RMS error of 60mm) and the ICP registration error (31mm). Its use is limited to the existence of two geometries that allow superposition: one in good condition and one damaged to compare.

This study aims to investigate the relationship of the persistence of metopic suture (PMS), frontal sinus volume (FSV), and olfactory fossa depth (OFD).Tomography scans of 1,603 patients aged 18-65 years were evaluated for the presence of PMS. In the study, 74 PMS cases and 74 controls were included. The appearance of each individual's frontal sinus was classified as aplasia, hypoplasia, or normal. Two observers independently measured the lateral lamella length (LLL), OFD, and FSV. Interobserver agreement was evaluated with the intraclass correlation coefficient (ICC) and Cohen's kappa coefficient (κ).The prevalence of PMS was found to be 4.99% [95% confidence interval (CI): 4.03-6.17]. The PMS group had five times higher hypoplasia/aplasia than the controls (52.70%, 95% CI: 41.48-63.66 and 10.81%, 95% CI: 5.58-19.91, respectively; p0.001). An "almost perfect" agreement was detected among observers for the frontal sinus appearance classification: κ=0.807, p0.001. The ICC of continuous measurements for OFD, LLL, and FSV, respectively, presented "excellent" reliability: 0.956, 0.958, and 0.981, with p0.001 for each. LLL was shorter, OFD was shallower, and FSV was smaller in the PMS group than the control group (p0.001). There was a moderate positive correlation between OFD, LLL, and FSV (r=0.306, r=0.302).This study interprets that the presence of PMS is related frontal sinus development and volume. With PMS, a smaller FS, shorter lateral lamella, and shallower olfactory fossa may be expected.Bu çalışma, persistan metopik sütür (PMS) ile olfaktör fossa derinliği (OFD), ve frontal sinüs volümü (FSV) arasındaki ilişkiyi araştırmayı amaçlamaktadır.Yaşları 18-65 arasında değişen 1.603 hastanın tomografileri PMS varlığı açısından değerlendirildi. Yetmiş dört PMS olgusu ve 74 kontrol çalışmaya dahil edildi. Her bireyin frontal sinüs görünümü aplazi, hipoplazi veya normal olarak sınıflandırıldı. Lateral lamella uzunluğu (LLU), OFD ve FSV ölçümleri iki gözlemci tarafından bağımsız olarak yapıldı. Gözlemciler arası uyum değerlendirilirken, sürekli değişkenler için sınıf içi korelasyon katsayısı (ICC) ve Cohen’s kappa katsayısı (κ) kullanıldı.PMS prevalansı %4,99 [güven aralığı (GA) %95: 4,03-6,17] olarak bulundu. Hipoplazi/aplazi, PMS grubunda kontrol grubuna göre beş kat daha fazlaydı (sırasıyla %52,70; GA %95: 41,48-63,66 ve %10,81; GA %95: 5,58-19,91, p0,001). Frontal sinüs görünüm sınıflandırması için gözlemciler arasında “mükemmel” bir uyum tespit edildi: κ=0,807, p0,001. OFD, LLU ve FSV için ICC “mükemmel” güvenilirlik sundu: Her biri için sırasıyla 0,956, 0,958 ve 0,981 ve p0,001. PMS grubunda, LLU daha kısaydı, OFD daha sığdı ve FSV, kontrol grubuna göre daha küçüktü (her biri için p0,001). OFD, LLU ve FSV arasında orta derecede pozitif korelasyon vardı (r=0,306, r=0,302).Bu çalışmanın sonucunda, PMS’nin frontal sinüs gelişimi ve volümü ile ilişkili olduğu bulunmuştur. PMS varlığında daha küçük bir FS, daha kısa lateral lamella ve daha az derin olfaktör fossa beklenebilir.

Aim To assess the impact of the COVID-19 outbreak on trends in hospital admissions and number of diagnostic and therapeutic procedures in the largest tertiary vascular center in Hungary. Patients and Methods A retrospective analysis was carried out. The first wave of the COVID-19 pandemic occurred approximately from March 15 until June 1 in Hungary. We have compared the same period of 2020 to 2019. Electronic medical records were reviewed for the clinical status of the patients and treatment-related information. Results The total number of diagnostic angiographies and therapeutic interventions in 2020 (N = 233) decreased significantly (P = 0.046) compared to 2019 (N = 373). The ratio of Fontaine stage I–II cases to Fontaine stage III–IV cases for both diagnostic angiographies and therapeutic interventions was significantly lower (OR, 2.11; 95% CI, 1.26–3.59; P = 0.007 and OR, 3.22; 95% CI, 1.67–6.52; P < 0.001) in 2020 (0.36 and 0.27) than in 2019 (0.77 and 0.89). There was also a negative but not significant change in the number of supra-aortic (including internal carotid artery stenting) (P = 0.128) and other vascular therapeutic interventions (superior vena caval stenting, hemodialysis access percutaneous transluminal angioplasty [PTA], visceral artery/vein PTA/stenting, embolization) (P = 0.452) in 2020 (N = 16 and N = 21) compared to 2019 (N = 39 and N = 37). Conclusion The first wave of the COVID-19 pandemic had a negative effect on the total number of endovascular procedures in the largest tertiary vascular center in Hungary.

Guangtai Shen, 1 Xiaoqiang Yu, 1 Tianyang Sun, 1 Tian Hou, 1 Heping He, 1 Tubuxin Bai, 1 Zhipeng Zhang, 1 Xiaoli Ding, 1 Qingping Li, 2 Ying Liang, 3 Yuhua Ma 4 1Department of Breast and Thyroid Surgery, Inner Mongolia Xing’an League People’s Hospital, Ulanhot, Inner Mongolia, 137400, People’s Republic of China; 2Department of Operating Room, Inner Mongolia Xing’an League People’s Hospital, Ulanhot, Inner Mongolia, 137400, People’s Republic of China; 3Department of Pathology, Inner Mongolia Xing’an League People’s Hospital, Ulanhot, Inner Mongolia, 137400, People’s Republic of China; 4Department of Anesthesiology, Inner Mongolia Xing’an League People’s Hospital, Ulanhot, Inner Mongolia, 137400, People’s Republic of ChinaCorrespondence: Xiaoqiang YuDepartment of Breast and Thyroid Surgery, Inner Mongolia Xing’an League People’s Hospital, Ulanhot, Inner Mongolia, 137400, People’s Republic of ChinaTel/Fax +86 0482-8413761Email yuxq66_dr@163.comObjective: To verify the volume similarity between unilateral mammary gland and autologous omentum in adult females.Methods: A total of 63 patients diagnosed with stage 0–II breast cancer and partial non-lactating multi-fistula mastitis in the breast surgery department of Inner Mongolia Xing’an League People’s Hospital from 2007 to 2020 were enrolled in the study, including 52 cases of stage 0–II breast cancer and 11 cases of non-lactating multi-fistula mastitis. The volume of the resected mammary gland and the omentum were measured by a “soft tissue measuring cylinder” and recorded. The appearance of the reconstructed breast was compared with that of the healthy side. The correlation between unilateral mammary gland volume and autologous omentum volume was analyzed by linear regression.Results: Valid data were obtained for 60 cases. Affected breast size, curve, texture, nipple, and inframammary fold after omentum breast reconstruction were similar and symmetrical to those of the unaffected side. Postoperative complications occurred in most patients; the majority of these (76.67%) involved numbness of the nipple, and other complications were few. Patient satisfaction with postoperative appearance, feel, and movement of the breast, as well as total treatment costs, was over 75.0%. Linear regression analysis indicates a linear relationship between subcutaneous gland volume (x) and autologous omentum volume (y): y = 0.9847x - 1.2132, R 2 = 0.9742.Conclusion: Only when the dissociated pedicled omentum is completely obtained under laparoscopy can the whole subcutaneous residual cavity of the mammary gland be filled to the same volume. This study verifies that the volume of the unilateral mammary gland is similar to that of the autologous omentum in adult females.Keywords: unilateral mammary gland, omentum, volume, similarity, laparoscope, breast reconstruction

Background: This study aimed to reveal changes in thyroid gland volume and functions in patients having undergone sleeve gastrectomy (SG). Methods: In this retrospective cohort study, the thyroid-s...

After total or subtotal maxillectomy, reconstruction using a free rectus abdominis myocutaneous (RAMC) flap is a fundamental and useful option. The purpose of the present study was to clarify the degree of flap volume change and volume distribution change with time after total or subtotal maxillectomy and free RAMC flap reconstruction and to examine the factors affecting the results.A total of 20 patients who underwent total or subtotal maxillectomy with free RAMC flap reconstruction were examined, and the flap volume change rate (volume at final evaluation [POD 181-360] / volume at initial evaluation [POD 5-30]) was investigated using the results of imaging tests. Moreover, the flap was divided into four blocks (A-D) in the cranio-caudal direction, and the volume change of each block was individually analyzed.The overall volume change rate of fat/muscle/total was 0.84 ± 0.21/0.36 ± 0.08/0.67 ± 0.15, at the mean follow-up period of 309±35 days after the operation. The multiple regression analysis revealed that weight loss (for fat), postoperative RT (for fat and muscle), and young age (for muscle) were independently associated with flap volume loss. The results also indicated that the fat volume was stable, whereas the muscle volume decreased to40% over time, assuming there were no influencing factors. Regarding flap volume distribution change, the fat volume tended to gather toward the central-cranial direction, while the muscle volume gathered toward the cranial direction, and total flap volume gathered toward the central direction.

This article presents a review of the methods of determining spleen size in sonography, computed tomography, and magnetic resonance imaging. The review aims to summarize the data on the methods of estimating the linear dimensions of the spleen and splenic volume and describe the physiological variability of spleen size depending on sex, age, and different physiological conditions. We systematized the methods used for measuring the spleen and presented them in the form of a table, analyzed the results of previous studies, and compared the accuracy of different methods of calculating the splenic volume using a variety of diagnostic methods.