3D Coverage Research Articles

Designing breezeways to enhance wind environments in high-density cities: A comprehensive analysis of ten morphological parameters

To advance urban breezeway designs, this paper presents a pioneering and comprehensive study of breezeway morphological parameters. Ten parameters, selected through extensive literature review, include coverage ratio, porosity, line density, sinuosity, rotation angle, width, length, average height, height variation, and aspect ratio. Regression analysis, utilizing over 200 data points collected from wind tunnel experiments in Hong Kong, established correlations between these parameters and pedestrian-level wind velocity ratio (VRpoint). Results reveal that among the 2D parameters, width, length, line density, and coverage ratio exhibit the strongest correlations with VRpoint, while aspect ratio and porosity emerge as significant factors among the 3D parameters. Notably, simple 2D parameters, coverage ratio and width, effectively substitute for their 3D counterparts, porosity and aspect ratio, in high-density urban areas. Furthermore, the results highlight the parameters’ relative contributions to urban ventilation. From a street-level perspective, VRpoint is primarily influenced by configurations of street segments (width, 80%) and street intersections (rotation angle, 20%). From a neighborhood-level perspective, permeability (coverage ratio, 35%), fragmentation (line density, 30%), and roughness (average height, 35%) are critical factors. Illustrative examples are provided to facilitate the translation of findings into spatial analysis tools and design guidelines to assist planners and decision-makers in sustainable developments.

Three-dimensional assessment of subchondral arc and hip joint coverage angles in the asymptomatic young adult hip.

The primary objective of this study was to develop a custom algorithm to assess three-dimensional (3D) acetabular coverage of the femoral head based on surface models generated from computed tomography (CT) imaging. The secondary objective was to apply this algorithm to asymptomatic young adult hip joints to assess the regional 3D acetabular coverage variability and understand how these novel 3D metrics relate to traditional two-dimensional (2D) radiographic measurements of coverage. The algorithm developed automatically identifies the lateral- and medial-most edges of the acetabular lunate at one-degree intervals around the acetabular rim based on local radius of curvature. The acetabular edges and the center of a best-fit sphere to the femoral head are then used to compute the mean 3D subchondral arc angles and hip joint coverage angles in five acetabular octants. This algorithm was applied to hip models generated from pelvis/hip CT imaging or abdomen/pelvis CT angiograms of 50 patients between 17 and 25 years of age who had no history of congenital or developmental hip pathology, neuromuscular conditions, or bilateral pelvic and/or femoral fractures. Corresponding 2D acetabular coverage measures of lateral center edge angle (LCEA) and acetabular arc angle (AAA) were assessed on the patients' clinical or digitally reconstructed radiographs. The 3D subchondral arc angle in the superior region (58.0 [54.6-64.8] degrees) was significantly higher (p < 0.001) than all other acetabular subregions. The 3D hip joint coverage angle in the superior region (26.2 [20.7-28.5] degrees) was also significantly higher (p < 0.001) than all other acetabular subregions. 3D superior hip joint coverage angle demonstrated the strongest correlation with 2D LCEA (r = 0.649, p < 0.001), while 3D superior-anterior subchondral arc angle demonstrated the strongest correlation with 2D AAA (r = 0.718, p < 0.001). The 3D coverage metrics in the remaining acetabular regions did not strongly correlate with typical 2D radiographic measures. The discrepancy between standard 2D measures of radiographic acetabular coverage and actual 3D coverage identified on advanced imaging indicates potential discord between anatomic coverage and the standard clinical measures of coverage on 2D imaging. As 2D measurement of acetabular coverage is increasingly used to guide surgical decision-making to address acetabular deformities, this work would suggest that 3D measures of acetabular coverage may be important to help discriminate local coverage deficiencies, avoid inconsistencies resulting from differences in radiographic measurement techniques, and provide a better understanding of acetabular coverage in the hip joint, potentially altering surgical planning and guiding surgical technique.

Three-Dimensional Coverage Path Planning for Cooperative Autonomous Underwater Vehicles: A Swarm Migration Genetic Algorithm Approach

Cooperative marine exploration tasks involving multiple autonomous underwater vehicles (AUVs) present a complex 3D coverage path planning challenge that has not been fully addressed. To tackle this, we employ an auto-growth strategy to generate interconnected paths, ensuring simultaneous satisfaction of the obstacle avoidance and space coverage requirements. Our approach introduces a novel genetic algorithm designed to achieve equivalent and energy-efficient path allocation among AUVs. The core idea involves defining competing gene swarms to facilitate path migration, corresponding to path allocation actions among AUVs. The fitness function incorporates models for both energy consumption and optimal path connections, resulting in iterations that lead to optimal path assignment among AUVs. This framework for multi-AUV coverage path planning eliminates the need for pre-division of the working space and has proven effective in 3D underwater environments. Numerous experiments validate the proposed method, showcasing its comprehensive advantages in achieving equitable path allocation, minimizing overall energy consumption, and ensuring high computational efficiency. These benefits contribute to the success of multi-AUV cooperation in deep-sea information collection and environmental surveillance.

3D regional evaluation of right ventricular myocardial work from cineCT.

Regional myocardial work (MW) is not measured in the right ventricle (RV) due to a lack of high spatial resolution regional strain (RS) estimates throughout the ventricle. We present a cineCT-based approach to evaluate regional RV performance and demonstrate its ability to phenotype three complex populations: end-stage LV failure (HF), chronic thromboembolic pulmonary hypertension (CTEPH), and repaired tetralogy of Fallot (rTOF). 49 patients (19 HF, 11 CTEPH, 19 rTOF) underwent cineCT and right heart catheterization (RHC). RS was estimated from full-cycle ECG-gated cineCT and combined with RHC pressure waveforms to create regional pressure-strain loops; endocardial MW was measured as the loop area. Detailed, 3D mapping of RS and MW enabled spatial visualization of strain and work strength, and phenotyping of patients. HF patients demonstrated more overall impaired strain and work compared to the CTEPH and rTOF cohorts. For example, the HF patients had more akinetic areas (median: 9%) than CTEPH (median: <1%, p=0.02) and rTOF (median: 1%, p<0.01) and performed more low work (median: 69%) than the rTOF cohort (median: 38%, p<0.01). The CTEPH cohort had more impairment in the septal wall; <1% of the free wall and 16% of the septal wall performed negative work. The rTOF cohort demonstrated a wide distribution of strain and work, ranging from hypokinetic to hyperkinetic strain and low to medium-high work. Impaired strain (-0.15≤RS) and negative work were strongly-to-very strongly correlated with RVEF (R=-0.89, p<0.01; R=-0.70, p<0.01 respectively), while impaired work (MW≤5 mmHg) was moderately correlated with RVEF (R=-0.53, p<0.01). Regional RV MW maps can be derived from clinical CT and RHC studies and can provide patient-specific phenotyping of RV function in complex heart disease patients. Evaluating regional variations in right ventricular (RV) performance can be challenging, particularly in patients with significant impairments due to the need for 3D spatial coverage with high spatial resolution. ECG-gated cineCT can fully visualize the RV and be used to quantify regional strain with high spatial resolution. However, strain is influenced by loading conditions. Myocardial work (MW) - measured clinically derived as the ventricular pressure-strain loop area - is considered a more comprehensive metric due to its independence of preload and afterload. In this study, we sought to develop regional RV myocardial work (MW) assessments in 3D with high spatial resolution by combining cineCT-derived regional strain with RV pressure waveforms from right heart catheterization (RHC). We developed our method using data from three clinical cohorts who routinely undergo cineCT and RHC: patients in heart failure, patients with chronic thromboembolic pulmonary hypertension, and adults with repaired tetralogy of Fallot.We demonstrate that regional strain and work provide different perspectives on RV performance. While strain can be used to evaluate apparent function, similar profiles of RV strain can lead to different MW estimates. Specifically, MW integrates apparent strain with measures of afterload, and timing information helps to account for dyssynchrony. As a result, CT-based assessment of RV MW appears to be a useful new metric for the care of patients with dysfunction.

Machine learning-based 3D scan coverage prediction for smart-control applications

Automatic control of a workpiece being manufactured is a requirement to ensure in-line correction and thus move towards a more intelligent manufacturing system. There is therefore a need to develop control strategies which are capable of taking precise account of real working conditions and enabling first-time-right control. As part of such a smart-control strategy, this paper introduces a machine learning-based approach capable of accurately predicting a priori the 3D coverage of a part according to a scan configuration given as input, i.e. predicting before scanning it which areas of the part will be acquired for real. This corresponds to a paradigm shift, where coverage estimation no longer relies on theoretical visibility criteria, but on rules learned from a large amount of data acquired in real-life conditions. The proposed 3D Scan Coverage Prediction Network (3DSCP-Net) is based on a 3D feature encoding and decoding module, which is capable of taking into account the specifics of the scan configuration whose impact on the 3D coverage is to be predicted. To take account of real working conditions, features are extracted at various levels, including geometric ones, but also features characterising the way structured-light projection behaves. The method is thus able to incorporate inter-reflection and overexposure issues into the prediction process. The database used for the training was built using an ad-hoc platform specially designed to enable the automatic acquisition and labelling of numerous point clouds from a wide variety of scan configurations. Experiments on several parts show that the method can efficiently predict the scan coverage, and that it outperforms conventional approaches based on purely theoretical visibility criteria.

Natural source-field induced polarisation exploration of an iron-oxide copper-gold (IOCG) deposit under thick cover

Induced polarisation (IP) is a common geophysical method of exploration for disseminated sulphides. However, in areas with deep (>200 m) and conductive (10 Ωm or less) cover, the technique is less successful as it requires a significant transmitter source and large-offset dipoles. An alternative approach is to use natural-variations in Earth’s external magnetic field as the polarising source of the signal, known as natural-field IP. This paper presents a study of extracting IP information from electrical dipole observations during a broadband magnetotelluric (MT) program with a 9 km by 9 km grid of 100 sites above the Vulcan IOCG deposit beneath 750 m of cover, ∼40 km north of the Olympic Dam IOCG mine in South Australia. Inter-site transfer functions between 95 sites and five reference sites at the southeast and southwest corners of the grid were computed to determine a phase shift between horizontal electric fields in the bandwidth of 1–100 s period. Phase shifts of up to – 5 degrees were centred on a region of brecciated hematite where drill holes intersected pyrite, and an inferred fault-zone from passive seismics that marks the boundary between upper crust that is resistive (>100 Ω.m) with high magnetic susceptibility to the south of the fault, and a region of conductive crust (<10 Ω.m) which is low magnetic susceptibility. Our study suggests that the natural-field IP method can identify regions of polarizable minerals beneath deep cover where artificial power sources cannot be feasibly deployed. Such surveys are cheaper, safer, and easier to deploy as only receivers are required, and 3D coverage can be obtained as the source-field is of much larger dimension than the survey array. In addition, the natural-field IP signals are observed as part of the MT program so that both electrical resistivity and polarisation parameters can be determined.

Autonomous Full 3D Coverage Using an Aerial Vehicle, Performing Localization, Path Planning, and Navigation Towards Indoors Inventorying for the Logistics Domain

Over the last years, a rapid evolution of unmanned aerial vehicle (UAV) usage in various applications has been observed. Their use in indoor environments requires a precise perception of the surrounding area, immediate response to its changes, and, consequently, a robust position estimation. This paper provides an implementation of navigation algorithms for solving the problem of fast, reliable, and low-cost inventorying in the logistics industry. The drone localization is achieved with a particle filter algorithm that uses an array of distance sensors and an inertial measurement unit (IMU) sensor. Navigation is based on a proportional–integral–derivative (PID) position controller that ensures an obstacle-free path within the known 3D map. As for the full 3D coverage, an extraction of the targets and then their final succession towards optimal coverage is performed. Finally, a series of experiments are carried out to examine the robustness of the positioning system using different motion patterns and velocities. At the same time, various ways of traversing the environment are examined by using different configurations of the sensor that is used to perform the area coverage.

Minimal number of sensors for 3D coverage

This paper presents some theoretical results on the smaller number Nk(a, b, c) of sensors to achieve k coverage for the 3D rectangular area [0, a] × [0, b] × [0, c]. The first properties outline some theoretical results for the numbers Nk(a, b, c), including symmetry, subadditivity, and monotony on each variable. We use then these results to establish some lower and upper bounds for Nk(a, b, c). The main contribution proposes a result concerning the minimal density of sensors to achieve k-coverage.

Surrogate-assisted sine Phasmatodea population evolution algorithm applied to 3D coverage of mobile nodes

Deploying static wireless sensor nodes is prone to network coverage gaps, resulting in poor network coverage. In this paper, an attempt is made to improve the network coverage by moving the locations of the nodes. A surrogate-assisted sine Phasmatodea population evolution algorithm (SASPPE) is used to evaluate the network coverage. A 50×50\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$50 \ imes 50$$\\end{document} hill simulation environment was tested for the number of nodes of 30 and 40 and radii of 3, 5 and 7, respectively. The results show that the SASPPE algorithm has the highest coverage, which can be up to 23.624% higher than the PPE algorithm, and up to 5.196% higher than the PPE algorithm, ceteris paribus. The SASPPE algorithm mixes the GSAM with LSAMs, which balances the computational cost of the algorithm and the algorithm’s ability to find optimal results. The use of hierarchical clustering enhances the stable type of the LSAMs. In addition, LSAMs are easy to fall into local optimality when they are modeled with local data, and the use of sine Phasmatodea population evolution algorithm (Sine-PPE) for searching in LSAMs alleviates the time for the algorithm to fall into local optimality. On 30D, 50D, and 100D, the proposed algorithm was tested by 7 test functions. The results show that the algorithm has significant advantages on most functions.

Towards improved 3D reconstruction of cystoscopies through real-time feedback for frame reacquisition.

Cystoscopic video can be cumbersome to review; however, preservation of data in the form of 3D bladder reconstructions has the potential to improve patient care. Unfortunately, not all cystoscopy videos produce viable reconstructions, because their underlying frames contain artifacts such as motion blur and bladder debris, which consequently make them unusable for 3D reconstructions. Here, we develop a real-time pipeline, termed the Assessment and Feedback Pipeline (AFP), that alerts clinicians when unusable frames are detected and encourages them to recollect the last few seconds of data. We show that the AFP classifies frames as usable or unusable with a balanced accuracy of 81.60% and demonstrate that use of the AFP improves 3D reconstruction coverage. These results suggest that clinical implementation of the AFP would improve 3D reconstruction quality through real-time detection and recollection of unusable frames.

Prediction of 3-Dimensional Coverage Surface Area of the Femoral Head in Hip Dysplasia Through Conventional Computed Tomography.

Assessment of 3-dimensional (3D) femoral head coverage is critical in evaluating, preoperative planning, and treating hip dysplasia. To (1) propose a mathematical model to establish 3D femoral head coverage using conventional computed tomography (CT), (2) determine the correlation of 2D parameters with 3D coverage, and (3) characterize the patterns of dysplasia based on 3D morphology. Cross-sectional study; Level of evidence, 3. We identified 30 patients (n = hips) with symptomatic dysplasia and 30 patients (n = hips) without dysplasia. Patients with dysplastic hips were matched with regard to sex, age, and body mass index to those with nondysplastic hips. Preoperative CTs were analyzed using 3D software, and 3D femoral head surface area coverage (FHSAC; in %) was assessed in 4 quadrant zones: anteromedial, anterolateral, posteromedial, and posterolateral. To assess lateral coverage of the femoral head, we introduced the anterolateral femoral head coverage angle (ALFC) and the posterolateral femoral head coverage angle (PLFC). Reduced femoral head coverage was more pronounced in dysplastic versus nondysplastic hips in the anterolateral quadrant (18% vs 40.7%, respectively) and posterolateral quadrant (35.8% vs 56.9%, respectively) (P < .0001 for both). Dysplastic hips had smaller ALFC and PLFC (18.4° vs 38.7°; P < .0001; 47.2° vs 72.3°; P = .0002). Anterolateral and posterolateral FHSAC were strongly correlated with the ALFC (r = 0.88; P < .0001) and the PLFC (r = 0.82; P < .0001) along with the lateral center-edge angle (anterolateral, r = 0.75; P < .0001; posterolateral, r = 0.73; P < .0001). Prediction models established for FHSAC had strong agreement with explanatory CT variables (anterolateral: r = 0.91; P < .0001; posterolateral: r = 0.90; P < .0001). The cutoff values for anterolateral and posterolateral FHSAC were 25% and 41%, respectively. In dysplastic hips, global deficiency was most common (15/30 hips), 9 hips showed an anterolateral deficiency, and 4 hips had a posterolateral deficiency pattern. The ALFC and The PLFC were strongly correlated with 3D lateral FHSAC and were able to predict 3D coverage accurately.

Urban 2D and 3D morphology and the pattern of ozone pollution: a 68-city study in China

ContextAir pollution significantly impacts urban sustainable development and public health. Urban ozone pollution (UOP) is currently one of the most challenging tasks for urban air pollution control, and is possibly linked to urban morphology. However, the effect of urban two-dimensional (2D) (coverage or density, etc.) and three-dimensional (3D) (density + height, etc.) morphology on the UOP concentration remains unclear.ObjectivesThe objective of this study was to explore the influence of urban morphology on UOP concentration and provide useful information to control urban air pollutants.MethodsFirst, based on building height and remotely sensed UOP data from 68 Chinese cities, the general spatial pattern of urban 3D morphology and UOP was detected across different climate zones in China. Then, this study used variance decomposition to investigate the contribution of 2D and 3D urban morphology to UOP in China.ResultsThe study showed that China's urban morphology was dominated by Medium Rise & Medium Density (MRMD). Large cities had higher UOP levels in summer, especially for the urban morphology with Low Rise & High Density (LRHD). Further, UOP concentrations were substantially higher in the southern temperate zone than in other climatic zones. Anthropogenic factors (rather than natural factors) were always the dominant factors influencing UOP across different seasons; specifically, urban 2D and 3D morphology can explain 40% of UOP variation. The effects of urban 3D and 2D morphologies on UOP concentrations varied seasonally. Urban 2D morphology dominated in spring, whereas 3D morphology dominated in winter.ConclusionsOur study elucidates the effect of urban morphology on UOP and provides insights for sustainable urban development.

Scalable Task Allocation with Communications Connectivity for Flying Ad-Hoc Networks

Task allocation enables heterogeneous agents to execute heterogeneous tasks in the domain of unmanned aerial vehicles, while responding to dynamic changes in the environment and available resources to complete complex, multi-objective missions, leading to swarm intelligence. We propose a bio-inspired approach using digital pheromones to perform scalable task allocation when the number of agents, tasks, and the diameter of the communications graph increase. The resulting emergent behaviour also enables idle agents in the swarm to provide periodic or continuous connectivity between disconnected parts of the swarm. We validate our results through simulation and demonstrate the feasibility of our approach by applying it to the 3D coverage and patrol problem.

AI-Based UAVs 3D Coverage Deployment in 6G-Enabled IoV Networks for Industry 5.0

AI-Based UAVs 3D Coverage Deployment in 6G-Enabled IoV Networks for Industry 5.0

User orientation and position-based transmission characteristics analysis of a LiFi system

Abstract The objective of the work is to analyze the downlink signal-to-interference-plus-noise ratio (SINR), transmission rate, bit error rate (BER), and average BER in terms of the irradiance angle of the receiver’s orientation and incident light and transmitter-to-receiver separation distance. The research considered two Light Fidelity (LiFi) access points (APs) for this analysis in a smart classroom context. The work derived the best favorable irradiance angle in terms of transmitter–receiver separation at which user devices achieve the highest SINR and transmission rate considering both two-dimensional (2D) and three-dimensional (3D) coverage areas. Moreover, the work analyzed SINR-based BER and average BER for the same communication scenario. The research derived that 47° to 50° irradiance angles of the receiver’s orientation and incident light offer the most favorable performance.

Evaluation of Automated Coverage and Distance Mapping Selections to Improve Reliability and Clinical Utility of 3D Weightbearing CT Assessments

Category: Other; Hindfoot Introduction/Purpose: Progressive collapsing foot deformity (PCFD) is a complex three-dimensional (3D) deformity where adjacent structures may adopt subtle differences in positioning that result in increased contact or subluxation. Recent studies have highlighted the need for and utility of 3D analyses in PCFD using weightbearing CT (WBCT) and bone segmentation. Beyond the limitations of triplanar imaging, 3D distance and coverage mapping analyses have further highlighted key regional differences like sinus tarsi narrowing ahead of impingement and early middle facet uncoverage ahead of collapse. However, these analyses rely upon manual identification of subregions hindering the utility of 3D mapping clinically. The objective of this study was to compare an automated selection process with manual selections in the context of subtalar regional distance and coverage maps in PCFD. Methods: In this IRB-approved retrospective study, WBCT data of 20 consecutive patients with flexible PCFD and 10 controls were analyzed. Subregions of the peritalar surface (middle and posterior facets of the calcaneus and talus; sinus tarsi area) were manually selected by two experts on manually generated bone surfaces of all 30 feet. An automated algorithm for selecting coverage area was applied to identify the same regions on the semi-automatically generated bones (Figure). A 3D distance mapping (DM) technique was used to create coverage maps (CMs) across the entire peritalar surface where areas with distances less than 4mm were defined as covered. DM and CM percentages were compared using intra-class correlations and t-tests between PCFD and control groups. The Sørensen–Dice index, or Dice coefficient, was used for comparisons of selections on the semi-automated surfaces to evaluate reproducibility of expert selections. Results: The automated process produced identical selections resulting in perfect intra-method ICCs of 1.00 for all regions and Dice coefficients of 1.00. The average Dice coefficient for all manual selections was 0.903 (range: 0.865-0.935) indicating that observers were able to reliably select the same regions with 90% overlap. When assessing reliability of manual selections, intra- observer ICCs ranged from 0.41-0.92 while inter-observer ICCs ranged from 0.47-0.99 were found. Despite strong significant correlations, average coverage was significantly lower in the sinus tarsi region of the automated selections vs the manual selections (34.3±16.8% vs 23.1±12.7%, p&lt; 0.005). However, mean distances in each region were not significantly different in the middle facet or the sinus tarsi regions (p=0.323, p=0.095, respectively). Conclusion: Understanding of the complex 3D deformities that constitute PCFD requires sensitive and reproducible measures. Fully automated 3D assessments of coverage and bone relations can help improve understanding these deformities aiding in diagnosis, staging, and objective evaluation of treatment effects. Prior work with this method has specifically identified the middle facet and sinus tarsi regions as being of particular importance. Compared to manual selections, these regions were well identified by the automated process. This represents a major step toward viable use of fully automated 3D coverage and distance mapping when evaluating PCFD patients.

Rapid Construction of 3D Biomimetic Capillary Networks with Complex Morphology Using Dynamic Holographic Processing

AbstractMicrovascular networks (MVNs) are crucial transportation systems in living creatures for nutrient distribution, fluid flow, energy transportation and so on. However, artificial manufacturing of MVNs, especially capillary networks with diameters (average 6 ≈ 9 µm), has always been a problem and bottleneck in tissue engineering due to the lack of efficient manufacturing methods. Herein, a dynamic holographic processing method is reported for producing 3D capillary networks with complex biomimetic morphologies. Combining the axial scanning of the focused beam and the dynamic display of holograms, biomimetic bifurcated microtubes, and porous microtubes with programmable morphologies are rapidly produced by two‐photon polymerization (TPP). As a proof‐of‐concept demonstration, porous microtubes are used as 3D capillary network scaffolds for culturing human umbilical vein endothelial cells (HUVECs) to facilitate the exchange of nutrients and metabolites. Endothelial cells around the vascular scaffolds manifest obvious tight connections and 3D coverage after 3 days in vitro, which reveals that the scaffolds play a significant role in the morphology of dense vascularization. This flexible and rapid method of producing capillary networks provides a versatile platform for vascular physiology, tissue regeneration, and other biomedical areas.

3D CEST MRI with an unevenly segmented RF irradiation scheme: A feasibility study in brain tumor imaging.

To integrate 3D CEST EPI with an unevenly segmented RF irradiation module and preliminarily demonstrate it in the clinical setting. A CEST MRI with unevenly segmented RF saturation was implemented, including a long primary RF saturation to induce the steady-state CEST effect, maintained with repetitive short secondary RF irradiation between readouts. This configuration reduces relaxation-induced blur artifacts during acquisition, allowing fast 3D spatial coverage. Numerical simulations were performed to select parameters such as flip angle (FA), short RF saturation duration (Ts2), and the number of readout segments. The sequence was validated experimentally with data from a phantom, healthy volunteers, and a brain tumor patient. Based on the numerical simulation and l-carnosine gel phantom experiment, FA, Ts2, and the number of segments were set to 20°, 0.3 s, and the range from 4 to 8, respectively. The proposed method minimized signal modulation in the human brain images in the kz direction during the acquisition and provided the blur artifacts-free CEST contrast over the whole volume. Additionally, the CEST contrast in the tumor tissue region is higher than in the contralateral normal tissue region. It is feasible to implement a highly accelerated 3D EPI CEST imaging with unevenly segmented RF irradiation.

Defining the Borderline Dysplastic Hip: High Variability in Acetabular Coverage and Femoral Morphology on Low-Dose Computed Tomography.

Borderline acetabular dysplasia is commonly radiographically defined as a lateral center-edge angle (LCEA) of 20° to 25°. While the variability of plain radiographic assessment of this population has been reported, an understanding of the variability of 3-dimensional (3D) hip morphology remains to be better defined. To investigate the variability of 3D hip morphology present on low-dose computed tomography (CT) in the setting of symptomatic borderline acetabular dysplasia and to determine if plain radiographic parameters correlate with 3D coverage. Cohort study (diagnosis); Level of evidence, 2. A total of 70 consecutive hips with borderline acetabular dysplasia undergoing hip preservation surgery were included in the current study. Plain radiographic evaluation included LCEA, acetabular inclination, anterior center-edge angle (ACEA), anterior wall index (AWI), posterior wall index (PWI), and alpha angles on anteroposterior, 45° Dunn, and frog-leg views. All patients underwent low-dose pelvic CT for preoperative planning, which allowed detailed characterization of 3D morphology relative to normative data. Acetabular morphology was assessed with radial acetabular coverage (RAC) calculated according to standardized clockface positions from 8:00 (posterior) to 4:00 (anterior). Coverages at 10:00, 12:00, and 2:00 were classified as normal, undercoverage, or overcoverage relative to 1 SD from the mean of normative RAC values. Femoral morphology was assessed with femoral version, alpha angle (measured at 1:00 increments), and maximum alpha angle. Correlation was assessed with the Pearson correlation coefficient (r). Lateral coverage (12:00 RAC) was deficient in 74.1% of hips with borderline dysplasia. Anterior coverage (2:00 RAC) was highly variable, with 17.1% undercoverage, 72.9% normal, and 10.0% overcoverage. Posterior coverage (10:00 RAC) was also highly variable, with 30.0% undercoverage, 62.9% normal, and 7.1% overcoverage. The 3 most common patterns of coverage were isolated lateral undercoverage (31.4%), normal coverage (18.6%), and combined lateral and posterior undercoverage (17.1%). The mean femoral version was 19.7°± 10.6° (range, -4° to 59°), with 47.1% of hips having increased femoral version (>20°). The mean maximum alpha angle was 57.2° (range, 43°-81°), with 48.6% of hips having an alpha angle ≥ 55°. The ACEA and AWI were poorly correlated with radial anterior coverage (r = 0.059 and 0.311, respectively), while the PWI was strongly correlated with radial posterior coverage (r = 0.774). Patients with borderline acetabular dysplasia demonstrate highly variable 3D deformities, including anterior, lateral, and posterior acetabular coverage; femoral version; and alpha angle. Plain radiographic assessments of anterior coverage are poorly correlated with anterior 3D coverage on low-dose CT.

Paper 65: Novel CT-Derived 3D Modeling Assessing Dysplastic Hips Versus Controls Demonstrates Decreased 2D Lateral Center Edge Angle, but not Tönnis Angle, Predicts Decreased 3D Anterolateral Coverage

Paper 65: Novel CT-Derived 3D Modeling Assessing Dysplastic Hips Versus Controls Demonstrates Decreased 2D Lateral Center Edge Angle, but not Tönnis Angle, Predicts Decreased 3D Anterolateral Coverage