3D Renderings Research Articles

Utility of transillumination and transparency renderings in 3D transthoracic imaging.

Transillumination (TI) is a new 3D rendering tool that uses a freely movable virtual light source to enhance depth, contours, and image detail. The TI model was recently modified to allow the operator adjust the degree of transparency of both cardiac and extra-cardiac structures. While the addition of transparency was shown to significantly improve quality in 3D transesophageal imaging, this has not yet been shown for transthoracic (TTE) imaging. We prospectively studied 35 patients who underwent clinically indicated TTE with standard 3D acquisition, as well as TI with and without transparency. Six experienced echocardiographers were shown images of all three display types in random order. Each image was scored independently using a Likert Scale while assessing each of the following aspects: ability to identify anatomy or pathology, depth perception, degree of anatomic detail, and border delineation. All experts perceived an incremental value of the transparency mode, compared to TI without transparency and standard 3D rendering, in terms of ability to identify anatomy or pathology (4.15 ± 0.97 vs. 3.88 ± 0.99 vs. 2.52 ± 1.41, p < 0.01), depth perception (4.33 ± 0.78 vs. 3.88 ± 0.82 vs. 2.29 ± 1.07, p < 0.01), degree of anatomic detail (4.08 ± 1.0 vs. 3.89 ± 0.79 vs. 2.31 ± 1.08, p < 0.01), and border delineation (4.44 ± 0.80 vs. 3.90 ± 0.78 vs. 2.42 ± 1.13, p < 0.01). Compared to standard 3D and TI renderings of TTE images, the addition of transparency significantly improves both image quality and diagnostic confidence.

Experimental program on the flexural response of steel joist top chord extensions

This article describes an experimental program performed to investigate the stability response of the top chord member of open web steel joists extending as cantilevered members to support floor or roof extensions. The program included 15 full-scale specimens. Four different cross-sections were examined: single-C's, double C's back-to-back, double angle back-to-back, and cross-sections formed by a C-shape and an angle placed back-to-back. C and angle cross-section profiles were varied as well as the boundary conditions used for the top chord extension. The buckled shapes were examined using digitally scanned 3D renderings and monitored image correlation data. The ultimate strength, strains and the displacements of the extensions were measured to characterize their behaviours and be able to reproduce the test results with numerical simulations. Tensile tests and 4-point bending tests were performed to characterize the material properties. The influence of the restraint conditions and the type of section on flexural strength is presented. In all extension tests, failure took place at, or near the support by a combination of flexural yielding, lateral-torsional buckling (LTB) and local buckling. Extensions built with single C shapes without top flange lateral bracing failed by LTB and could not reach their plastic flexural strength. All specimens with top flange bracing could attain their plastic flexural capacity, although local buckling was observed near the bearing seats in most cases. For the deeper 2-C cross-sections, LTB of the individual C shapes also occurred near the support. Design methods for joist top chord extensions must account for these instability mechanisms.

Smartphone-Based Light Detection and Ranging for Remote Patient Evaluation and Monitoring.

LIDAR (from “light detection and ranging” or “laser imaging, detection, and ranging”) is an evolving three-dimensional scanning technology with historical applications in various fields. However, the applicability of LIDAR in the field of medicine has mostly not been examined thus far. Here, we review the basic principles governing LIDAR and its potential to be used in three notable use cases in the context of remote patient monitoring: geriatric fall prevention, postoperative recovery monitoring, and home safety assessment. For assisting geriatric populations, LIDAR can create 3D renderings of their home environments and classify which objects may be associated with risk for falls. These risk factors can then be forwarded to both patients and providers in order for them to discuss how to make the patient’s environment safer. LIDAR is also capable of mapping the range of extremity motion in patients undergoing postoperative recovery. Such LIDAR data is simple to acquire and record for these patients and could enable unique metrics to be developed to assess patient outcomes in postoperative recovery. Finally, LIDAR can also reproduce 3D home models to identify attributes of their environments that could be harmful to infants. Given the recent momentum in telehealth following the events of the coronavirus 2019 disease (COVID-19) pandemic, LIDAR may also be a powerful tool in driving new insights from quality improvement initiatives through remote patient monitoring.

Rock mass performance monitoring with topology preserving quantised vector spaces

This work explains the development of a so-called rock mass system performance map, that provides a backdrop to assist in performance interpretation. The rock mass system performance maps presented in this paper are 2D graphical devices prepared using Sammon mappings, Learning Vector Quantisation, Self-Organising Topological Maps and combinations of these mathematical techniques. Using supervised or unsupervised learning methods, these algorithms project and partition high-dimensional vector spaces, of a dimension equal to the number of environmental and rock mass condition parameters considered, into 2D categories of rock mass condition. In providing 2D renderings, the techniques aim to preserve properties of the characterising vector space such as adjacency of states and topology. The condition of a rock mass can be ‘plotted’ on that map by identifying its k-nearest neighbours and interpreted relative to stability metric categories. Should the defining vector space include rock mass properties or environmental parameters that are repeatedly measured, or possibly continuously monitored, then the rock mass condition marker traces out a performance trajectory across the performance map. An example of rock mass performance map synthesis and use is presented.

Research on China’s the Oldest Wooden Building Structure in the Tang Dynasty-the Restoration Model of the Main Hall of Nanchan Temple, Re-Understanding the Value of Heritage

China has a long five thousand years of cultural history. There is much precious architectural heritage have been preserved, and during the most prosperous period of the Tang Dynasty, there are only two wooden structures of the Tang Dynasty that have been preserved. They are the Main Hall of Nanchan Temple and the Main Hall of Foguang Temple in Wutai Mountain, Shanxi Province, China. This paper is based on the Main Hall of Nanchan Temple, which was established more than 1,200 years ago, as the research object. By referring to the restoration report in 19801, the 1/10 scale large wooden structure model of the Main Hall of Nanchan Temple was made for the first time; the Main Hall of Nanchan Temple drawings and 3D renderings was systematically drawn. Secondly, this paper analyses and interprets the three criteria for identifying the value of the heritage, combined with the status of Chinese heritage protection, and from the perspective of the authenticity and integrity of the heritage, combined with the two restoration fortifications of the Main Hall of Nanchan Temple, and systematically carried out. After sorting out, summed up constructive opinions suitable for the protection of Chinese heritage, to better highlight the universal value of heritage.

Depth correction of 3D NanoSIMS images using secondary electron pixel intensities.

Strategies that do not require additional characterization to be performed on the sample or the collection of additional secondary ion signals are needed to depth correct 3D SIMS images of cells. Here, we develop a depth correction strategy that uses the pixel intensities in the secondary electron images acquired during negative-ion NanoSIMS depth profiling to reconstruct the sample morphology. This morphology reconstruction was then used to depth correct the 3D SIMS images that show the components of interest in the sample. As a proof of concept, we applied this approach to NanoSIMS depth profiling data that show the 15N-enrichment and 18O-enrichment from 15N-sphingolipids and 18O-cholesterol, respectively, within a metabolically labeled Madin-Darby canine kidney cell. Comparison of the cell morphology reconstruction to the secondary electron images collected with the NanoSIMS revealed that the assumption of a constant sputter rate produced small inaccuracies in sample morphology after approximately 0.66 μm of material was sputtered from the cell. Nonetheless, the resulting 3D renderings of the lipid-specific isotope enrichments better matched the shapes and positions of the subcellular compartments that contained 15N-sphingolipids and 18O-cholesterol than the uncorrected 3D SIMS images. This depth correction of the 3D SIMS images also facilitated the detection of spherical cholesterol-rich compartments that were surrounded by membranes containing cholesterol and sphingolipids. Thus, we expect this approach will facilitate identifying the subcellular structures that are enriched with biomolecules of interest in 3D SIMS images while eliminating the need for correlated analyses or additional secondary ion signals for the depth correction of 3D NanoSIMS images.

Full circumferential morphological analysis of Schlemm's canal in human eyes using megahertz swept source OCT.

We performed full circumferential imaging of the Schlemm's canal (SC) of two human eyes using a Fourier domain mode-lock laser (FDML) based 1.66-MHz SS-OCT prototype at 1060 nm. Eight volumes with overlapping margins were acquired around the limbal area with customized raster scanning patterns designed to fully cover the SC while minimizing motion artifacts. The SC was segmented from the volumes using a semi-automated active contour segmentation algorithm, whose mean dice similarity coefficient was 0.76 compared to the manual segmentation results. We also reconstructed three-dimensional (3D) renderings of the 360° SC by stitching the segmented SCs from the volumetric datasets. Quantitative metrics of the full circumferential SC were provided, including the mean and standard deviation (SD) of the cross-sectional area (CSA), the maximum CSA, the minimum and maximum SC opening width, and the number of collector channels (CC) stemming from the SC.

3D Volume Rendering Pulmonary Reconstructions in Covid-19 pneumonia at Computed Tomography

3D Volume Rendering Pulmonary Reconstructions in Covid-19 pneumonia at Computed Tomography

Investigating the evolution of fractures in clay–based ceramics during repeated freeze-thawing cycles using X-ray micro-computed tomography and image analysis

This work presents a study on the fracturing behaviour of a quartz tempered clay-based ceramic subjected to damage in freeze-thaw cycles. X-ray micro-computed tomography (micro-CT) provided high-resolution imaging of the ceramic before and during the freeze-thaw treatment, allowing to analyse a fully water-saturated sample using a special thermal stage designed to keep the sample frozen during analyses. Micro-CT 3D renderings showed the internal features of the specimen (i.e., quartz grain distribution), the increment of fracture count and size, and the detachment of ceramic and/or temper fragments from the edges of the sample over the cycles. Selected 2D micrographs, before and after freeze-thawing treatment, were analysed using the MATLAB toolbox FracPaQ. This software provided detailed data on fracture length, intensity, density, orientation and connectivity, and enabled to interpret the process of fracture initiation and propagation inside the material. These results showed that the temper plays a crucial role in ceramic fracturing behaviour under freeze-thawing conditions, as damage propagation is influenced by quartz grain distribution and orientation within the material. The study described in this work, not only offers new insights into the fracture dynamics of freeze-thawed clay-based ceramics, but also presents a new methodological approach to quantitatively measure fracture damage in porous materials.

Automatic Segmentation of Bone Selective MR Images for Visualization and Craniometry of the Cranial Vault

Solid-state MRI has been shown to provide a radiation-free alternative imaging strategy to CT. However, manual image segmentation to produce bone-selective MR-based 3D renderings is time and labor intensive, thereby acting as a bottleneck in clinical practice. The objective of this study was to evaluate an automatic multi-atlas segmentation pipeline for use on cranial vault images entirely circumventing prior manual intervention, and to assess concordance of craniometric measurements between pipeline produced MRI and CT-based 3D skull renderings. Dual-RF, dual-echo, 3D UTE pulse sequence MR data were obtained at 3T on 30 healthy subjects along with low-dose CT images between December 2018 to January 2020 for this prospective study. The four-point MRI datasets (two RF pulse widths and two echo times) were combined to produce bone-specific images. CT images were thresholded and manually corrected to segment the cranial vault. CT images were then rigidly registered to MRI using mutual information. The corresponding cranial vault segmentations were then transformed to MRI. The "ground truth" segmentations served as reference for the MR images. Subsequently, an automated multi-atlas pipeline was used to segment the bone-selective images. To compare manually and automatically segmented MR images, the Dice similarity coefficient (DSC) and Hausdorff distance (HD) were computed, and craniometric measurements between CT and automated-pipeline MRI-based segmentations were examined via Lin's concordance coefficient (LCC). Automated segmentation reduced the need for an expert to obtain segmentation. Average DSC was 90.86 ± 1.94%, and average 95th percentile HD was 1.65 ± 0.44 mm between ground truth and automated segmentations. MR-based measurements differed from CT-based measurements by 0.73-1.2 mm on key craniometric measurements. LCC for distances between CT and MR-based landmarks were vertex-basion: 0.906, left-right frontozygomatic suture: 0.780, and glabella-opisthocranium: 0.956 for the three measurements. Good agreement between CT and automated MR-based 3D cranial vault renderings has been achieved, thereby eliminating the laborious manual segmentation process. Target applications comprise craniofacial surgery as well as imaging of traumatic injuries and masses involving both bone and soft tissue.

Identifying optimal graphical level of detail to support orienting with 3D geo-visualizations

ABSTRACT Limited hardware processing capacities and network bandwidth constrain the quality and quantity of photogrammetrically derived 3D terrain models that users can effectively visualize. In the present study, we examined what graphical level of detail (LOD) is sufficient to support effective spatial localization and orientation in 3D renderings of large-scale environments. We developed an interactive desktop split-screen orienting and geo-visualization task using photogrammetrically derived 3D terrain models, manipulating LOD on a trial-by-trial basis, tracking interactions during geo-visualization, and measuring orienting performance. Results demonstrated moderate (rather than maximum) LOD is sufficient for spatial orientation, suggesting new guidelines for the collection, transmission, and visualization of terrain models on end-user devices. We discuss these findings within the context of spatial perception, cognition, and behavior.

Stereoscopic virtual reality does not improve knowledge acquisition of congenital heart disease.

Advances in virtual reality have made it possible for clinicians and trainees to interact with 3D renderings of hearts with congenital heart disease in 3D stereoscopic vision. No study to date has assessed whether this technology improved instruction compared to standard 2D interfaces. The purpose of this study was to assess whether stereoscopic virtual reality improves congenital heart disease anatomy education. Subjects in a prospective, blinded, randomized trial completed a pre-test assessing factual and visuospatial knowledge of common atrioventricular canal and were randomized to an intervention or control group based on their score. The intervention group used a 3D virtual reality (VR) headset to visualize a lecture with 3D heart models while the control group used a desktop (DT) computer interface with the same models. Subjects took a post-test and provided subjective feedback. 51 subjects were enrolled, 24 in the VR group & 27 in the DT group. The median score difference for VR subjects was 12 (IQR 9-13.3), compared to 10 (IQR 7.5-12) in the DT group. No difference in score improvement was found (p = 0.11). VR subjects' impression of the ease of use of their interface was higher than DT subjects (median 8 vs 7, respectively, p = 0.01). VR subjects' impression of their understanding of the subject matter was higher than desktop subjects (median 7 vs 5, respectively, p = 0.01). There was no statistically significant difference in the knowledge acquisition observed between the stereoscopic virtual reality group and the monoscopic desktop-based group. Participants in virtual reality reported a better learning experience and self-assessment suggesting virtual reality may increase learner engagement in understanding congenital heart disease.

Gene Therapy of Dominant CRX-Leber Congenital Amaurosis using Patient Stem Cell-Derived Retinal Organoids.

SummaryMutations in the photoreceptor transcription factor gene cone-rod homeobox (CRX) lead to distinct retinopathy phenotypes, including early-onset vision impairment in dominant Leber congenital amaurosis (LCA). Using induced pluripotent stem cells (iPSCs) from a patient with CRX-I138fs48 mutation, we established an in vitro model of CRX-LCA in retinal organoids that showed defective photoreceptor maturation by histology and gene profiling, with diminished expression of visual opsins. Adeno-associated virus (AAV)-mediated CRX gene augmentation therapy partially restored photoreceptor phenotype and expression of phototransduction-related genes as determined by single-cell RNA-sequencing. Retinal organoids derived from iPSCs of a second dominant CRX-LCA patient carrying K88N mutation revealed the loss of opsin expression as a common phenotype, which was alleviated by AAV-mediated augmentation of CRX. Our studies provide a proof-of-concept for developing gene therapy of dominant CRX-LCA and other CRX retinopathies.

Product representations in conjoint analysis in an LMIC setting: Comparing attribute valuation when three-dimensional physical prototypes are shown versus two-dimensional renderings

Conjoint experiments (CEs) provide designers with insights into consumer preferences and are one of several user-based design approaches aimed at meeting users’ needs. Traditional CEs require participants to evaluate products based on two-dimensional (2D) visual representations or written lists of attributes. Evidence suggests that product representations can affect how participants perceive attributes, an effect that might be exacerbated in a Low- and Middle-Income Country setting where CEs have seldom been studied.This study examined how physical three-dimensional (3D) prototypes and 2D renderings with written specifications of attribute profiles generated differences in estimated utilities of a CE about a hypothetical new tool for electronic-waste recycling, among workers in North-Eastern Thailand. Two independent CEs were performed with each representation form. Ninety participants across both experiments each ranked three sets of five alternative tool concept solutions from most to least preferred. The results of the conjoint analysis guided the design of a tool optimized for user preferences, which was then distributed to half of the sample through a Becker-DeGroot-Marschak auction experiment. One month after the auction, participants completed an endline survey.The results point toward potential differences in relative importance of different product attributes based on product representation. Price was found to have no significant impact on the valuation of tools in either experiment. The differences in relative importance of product attributes may have been explained by the limitations of 2D renderings for conveying sizes.Further research is needed to understand the impact of product representation on preferences in this context. We recommend careful consideration for product representations – specifically, how well the representations convey all product attributes being evaluated – in CEs. Using a combination of 2D renderings and 3D product features might have satisfied both the speed and low-cost advantages of renderings while enabling participants to have a better sense of product features.

Methods of 3d Rendering in Modern Web-Browsers

This paper reviews methods of rendering 3d models in modern web-browsers, texture mapping for the model and methods of creating and integrating a javascript-library into a modern web-application. The result of this paper, is a web-application for an online service to view 3d models of clothes on a 3d model of a human in a web-browser and a demonstration of the usage of the library.Every day, many people shop online. There are online stores for this. You can easily order any product you need from them. However, there is a problem with products for which the size or appearance of the product is important, namely clothing. When buying clothes online, the buyer is often not sure if a certain thing will suit him, because there is no way to look at clothes with other clothes. For example, the buyer orders a T-shirt or pants, but he is not sure whether the combination will be successful or not. The purpose of the work is to solve this problem, namely, to give customers the opportunity to view a combination of different pieces of clothing (T-shirts and pants) on a 3-d mannequin.Currently, there are many javascript libraries for displaying 3D graphics in a web browser. However, most of them require some knowledge in the field of 3-d visualization, namely: formats of 3-d models; cartesian coordinates in three-dimensional space; texture maps and materials; lighting; cameras and field of view.Although most libraries (detailed analysis and comparison in the next section) do not require complete and in-depth knowledge in this area, some things may not be obvious. Because of this, trivial problems can take a lot of time that could go into developing your own product.As it is shown that there are several scenarios where this technology would be useful, it has been decided to create a javascript library so that this code could be reused in various projects, in one way or another related to the technology of 3D visualization of clothing. Also, creating a library will allow you to divide the code of your own project into different parts, or speed up development and reduce the number of errors during the development, testing and deployment of the project.Manuscript received 10.06.2020

18280 3D rendering of lentigo maligna features in vivo

Reflectance confocal microscopy (RCM) is now available for clinical use to evaluate cutaneous lesions in vivo before biopsy. This technology is particularly valuable for patients where there is concern of melanoma on sun damaged skin (lentigo maligna) versus a benign lentigo or seborrheic keratosis. Trained physicians can identify lentigo maligna tumors using 2D horizontal RCM image stacks or mosaics. However, there is valuable information missing when assessing lesions in 2D. Instead of reviewing only the 2D confocal images, we have generated 3D renderings of image stacks to augment our ability to visualize relevant features. Presently our efforts are focused on 3 areas of interest. 1) The extent of melanocytic dendricity: a hallmark of lentigo maligna tumors evident in RCM. Dendrites reside in multiple planes, therefore their morphology can only be fully revealed with 3D reconstructions. 2) The location of melanocytic cells within the context of the 3D volume: making upper (epidermal) regions and lower (dermal) regions simultaneously apparent. 3) The normal undulation of the dermal-epidermal junction: this wave-like interface becomes flattened or eroded in lentigo maligna as compared with benign neoplasms. Visualization of the DEJ structure (or lack of) which transects the horizontal planes of RCM image stacks is only possible in 3D. The impact of 3D confocal images on clinical care and potential artificial intelligence (AI) diagnostic algorithms has yet to be fully determined. Currently 3D processing provides critical data regarding location, structure and morphology, thereby supporting the diagnostic capabilities of RCM.

MicroCT Imaging of Heart Valve Tissue in Fluid.

Heart valve computational models require high quality geometric input data, commonly obtained using micro-computed tomography. Whether in the open or closed configuration, most studies utilize dry valves, which poses significant challenges including gravitational and surface tension effects along with desiccation induced mechanical changes. These challenges are overcome by scanning in a stress-free configuration in fluid. Utilizing fluid backgrounds however reduces overall contrast due to the similar density of fluid and tissue. The work presented here demonstrates imaging of the mitral valve by utilizing an iodine-based staining solution to improve the contrast of valve tissue against a fluid background and investigates the role of stain time and concentration. It is determined that an Olea europaea oil bath with a relatively high concentration, short stain time approach produces high quality imagery suitable for creating accurate 3D renderings. Micro-CT scanning of heart valves in fluid is shown to be feasible using iodine staining techniques.

Comprehensive non-invasive analysis of lower urinary tract anatomy using MRI.

Anatomic changes that coincide with aging including benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) negatively impact quality of life. Use of MRI with its exquisite soft tissue contrast, full field-of-view capabilities, and lack of radiation is uniquely suited for quantifying specific lower urinary tract features and providing comprehensive measurements such as total bladder wall volume (BWV), bladder wall thickness (BWT), and prostate volume (PV). We present a technique for generating 3D anatomical renderings from MRI to perform quantitative analysis of lower urinary tract anatomy. T2-weighted fast-spin echo MRI of the pelvis in 117 subjects (59F;58M) aged 30-69 (49.5 ± 11.3) without known lower urinary tract symptoms was retrospectively segmented using Materialise software. Virtual 3D models were used to measure BWV, BWT, and PV. BWV increased significantly between the 30-39 and 60-69year age group in women (p = 0.01), but not men (p = 0.32). BWV was higher in men than women aged 30-39 and 40-49 (p = 0.02, 0.05, respectively) ,but not 50-59 or 60-69 (p = 0.18, 0.16, respectively). BWT was thicker in men than women across all age groups. Regional differences in BWT were observed both between men and women and between opposing bladder wall halves (anterior/posterior, dome/base, left/right) within each sex in the 50-59 and 60-69year groups. PV increased from the 30-39 to 60-69year groups (p = 0.05). BWT was higher in subjects with enlarged prostates (> 40cm3) (p = 0.05). Virtual 3D MRI models of the lower urinary tract reliably quantify sex-specific and age-associated changes of the bladder wall and prostate.

Bone-Selective Magnetic Resonance Imaging as a Nonradiative Alternative to Computed Tomography for Cranial Vault Imaging: Concordance and Implementation of an Automated Segmentation Pipeline for Timely Image Processing

BACKGROUND: Computed tomography (CT) is the clinical gold standard for high-resolution 3-dimensional (3D) visualization of cortical bone structures. However, CT ionizing radiation exposure is associated with the development of malignancy. Bone-selective magnetic resonance imaging (MRI) and bone-selective image reconstruction provide a radiation-free imaging modality with diagnostic and surgical planning uses. This technique, though applicable to many realms of plastic and reconstructive surgery, is of specific interest to craniofacial surgeons whose patients often require multiple pre- and postoperative CT scans, enduring a higher cumulative risk of malignancy. As it stands, the implementation of bone-selective MRI in clinical practice is prevented by a paucity of CT and bone-selective MRI concordance data and the time and labor intensive process required to produce bone-selective MR-based 3D skull segmentations. The manual segmentation process takes about 1.5 hours of time per MRI. Our study evaluates both the accuracy of a novel bone-selective MRI technique (dual-radiofrequency pulse, dual-echo, 3D ultrashort echo time) and the utility of a segmentation pipeline. OBJECTIVES: Part 1. Evaluate the concordance between MR-based and CT-based 3D skull renderings Part 2. Describe and evaluate a novel multiatlas segmentation pipeline DESIGN/METHODS: Part 1: A cadaver skull and the skulls of 5 healthy adult volunteers were scanned with bone-selective MR and thin-slice CT. Semi-automatic bone segmentation (1.5 hours/scan) was performed creating 3D renderings of the skulls. Mimics software was used to measure 8 anatomic distances from the 3D renderings. Lin’s Concordance Correlation test was applied to assess agreement between MR and CT-based 3D renderings. Part 2. CT and bone-selective MR images were acquired from 16 additional healthy adult volunteers, yielding 21 MR/CT pairs. The CT images were segmented using a semi-automated method to generate “ground truth” labels for the MR images. An automated multiatlas segmentation pipeline was then used to segment the 3D MR images using a 2-step process consisting of a training and segmentation. The training step develops an “atlas package,” which represents the varying anatomy from different subjects. The segmentation step uses the atlas package to generate segmentations for new subjects using several image registration steps. RESULTS: MR-based measurements differed from CT-based measurements by mean percent difference ranging from 2.3% to 5.0%. Lin’s Concordance Correlation ranged from 0.998 to 1.000. The segmentation pipeline took 10 minutes per segmentation with an average symmetric surface distance of 0.96 ± 0.15 mm between the manual reference segmentation and the corresponding automated segmentations. CONCLUSIONS: This study demonstrates high concordance between the gold standard (thin-slice CT) and our novel imaging modality as well as an 89% reduction in segmentation time. This technique is highly applicable to craniofacial surgery as well as cases involving extremity surgery, musculoskeletal trauma, and bone tumors. It additionally allows acquision of data of both soft and hard tissue structures from a single imaging modality with no radiation exposure. The demonstrated reduced segmentation time would allow bone-selective MRI to be used in clinical practice without a delay in treatment. We plan to investigate the accuracy of this technique as a tool for craniosynostosis diagnosis as well as in craniofacial virtual surgical planning.

Assessment of manual adjustment performed in clinical practice following deep learning contouring for head and neck organs at risk in radiotherapy.

Background and purposeAuto-contouring performance has been widely studied in development and commissioning studies in radiotherapy, and its impact on clinical workflow assessed in that context. This study aimed to evaluate the manual adjustment of auto-contouring in routine clinical practice and to identify improvements regarding the auto-contouring model and clinical user interaction, to improve the efficiency of auto-contouring.Materials and methodsA total of 103 clinical head and neck cancer cases, contoured using a commercial deep-learning contouring system and subsequently checked and edited for clinical use were retrospectively taken from clinical data over a twelve-month period (April 2019–April 2020). The amount of adjustment performed was calculated, and all cases were registered to a common reference frame for assessment purposes. The median, 10th and 90th percentile of adjustment were calculated and displayed using 3D renderings of structures to visually assess systematic and random adjustment. Results were also compared to inter-observer variation reported previously. Assessment was performed for both the whole structures and for regional sub-structures, and according to the radiation therapy technologist (RTT) who edited the contour.ResultsThe median amount of adjustment was low for all structures (<2 mm), although large local adjustment was observed for some structures. The median was systematically greater or equal to zero, indicating that the auto-contouring tends to under-segment the desired contour.ConclusionAuto-contouring performance assessment in routine clinical practice has identified systematic improvements required technically, but also highlighted the need for continued RTT training to ensure adherence to guidelines.