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1.
Sensors (Basel) ; 21(11)2021 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-34071704

RESUMEN

Vision-based 3D human pose estimation approaches are typically evaluated on datasets that are limited in diversity regarding many factors, e.g., subjects, poses, cameras, and lighting. However, for real-life applications, it would be desirable to create systems that work under arbitrary conditions ("in-the-wild"). To advance towards this goal, we investigated the commonly used datasets HumanEva-I, Human3.6M, and Panoptic Studio, discussed their biases (that is, their limitations in diversity), and illustrated them in cross-database experiments (for which we used a surrogate for roughly estimating in-the-wild performance). For this purpose, we first harmonized the differing skeleton joint definitions of the datasets, reducing the biases and systematic test errors in cross-database experiments. We further proposed a scale normalization method that significantly improved generalization across camera viewpoints, subjects, and datasets. In additional experiments, we investigated the effect of using more or less cameras, training with multiple datasets, applying a proposed anatomy-based pose validation step, and using OpenPose as the basis for the 3D pose estimation. The experimental results showed the usefulness of the joint harmonization, of the scale normalization, and of augmenting virtual cameras to significantly improve cross-database and in-database generalization. At the same time, the experiments showed that there were dataset biases that could not be compensated and call for new datasets covering more diversity. We discussed our results and promising directions for future work.


Asunto(s)
Imagenología Tridimensional , Iluminación , Bases de Datos Factuales , Humanos
2.
Medicine (Baltimore) ; 100(22): e26247, 2021 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-34087913

RESUMEN

RATIONALE: Open total dislocation of ankle joint is rare and often caused by high-energy injury. The present study describes a patient with open total lateral dislocation of ankle joint without fractures and obtained a satisfactory clinical result following early debridement and irrigation, one-stage repairment of ligaments, and plaster external fixation. PATIENT CONCERNS: The patient, a 45-year-old male, complained of right foot pain with bleeding and limited motion. Physical examination showed a 15-cm open wound at the medial ankle region, with soft tissues impaired and ankle bones exposed. The 3 dimensional reconstruction computed tomography (CT) examination showed an open total dislocation of ankle joint without concomitant fractures. DIAGNOSES: open total lateral dislocation of ankle joint without fractures. INTERVENTIONS: Early modern wound care including thorough debridement and irrigation on the wound was performed to remove contaminated soft tissues. Subsequently, the dislocated ankle joint was reduced by hand and the medial and lateral collateral ligaments were repaired using wire anchors. OUTCOMES: The medial wound healed at 2 weeks after surgery, and several common complications such as infection and skin necrosis did not occur. The last follow-up showed a good range of metatarsal flexion and extension of the injured foot, and obvious signs of traumatic arthritis were not observed. According to Kaikkonen ankle function score, the patient was assessed with 90 points. LESSONS: For open total dislocation of ankle joint, early treatment should focus on debridement and irrigation, reduction and fixation of the dislocated ankle, protection of the weak soft tissues, and stable external fixation to promote wound healing and reduce the incidence of related complications.


Asunto(s)
Articulación del Tobillo/patología , Desbridamiento/métodos , Luxaciones Articulares/cirugía , Irrigación Terapéutica/métodos , Cuidados Posteriores , Articulación del Tobillo/diagnóstico por imagen , Humanos , Imagenología Tridimensional/instrumentación , Luxaciones Articulares/diagnóstico , Ligamentos Laterales del Tobillo/lesiones , Ligamentos Laterales del Tobillo/cirugía , Masculino , Persona de Mediana Edad , Rango del Movimiento Articular/fisiología , Traumatismos de los Tejidos Blandos/patología , Traumatismos de los Tejidos Blandos/cirugía , Tomografía Computarizada por Rayos X/métodos , Resultado del Tratamiento , Heridas y Lesiones/patología , Heridas y Lesiones/cirugía
3.
Shanghai Kou Qiang Yi Xue ; 30(2): 219-224, 2021 Apr.
Artículo en Chino | MEDLINE | ID: mdl-34109367

RESUMEN

PURPOSE: To use three-dimensional reconstruction measurement, preoperative diagnosis, surgical design, surgical simulation, guide plate production, navigation verification and effect evaluation of orthognathic surgery assisted by digital technology, in order to explore more scientific and reasonable programs and procedures of orthognathic surgery. METHODS: Twenty-five patients with congenital dental and maxillofacial deformity were selected as the experimental subjects, craniofacial spiral CT was conducted before surgery and CT data were imported into Mimics 20.0 software to establish a 3D head digital model. The bone landmarks in three-dimensional reconstruction digital model were selected, measured, analyzed and diagnosed, and the design of the surgical plan and the production of the guide plates were performed. Surgical navigation system was used to confirm the maxillary position, verify the bone retention and guide precise bone grinding during operation. Craniofacial spiral CT was conducted 1 week after surgery for postoperative validation of the surgical design protocol. Statistical analysis was performed using SPSS 24.0 software package. RESULTS: All 25 patients were operated according to the digital orthognathic surgery design and procedure.There were no significant differences in X, Y and Z three-dimensional directions in 10 actual landmarks between the postoperative actual head model and the preoperative predictive head model(P>0.05). CONCLUSIONS: Orthognathic surgery assisted by digital technology has the advantages of precision and minimal invasiveness.


Asunto(s)
Cirugía Ortognática , Procedimientos Quirúrgicos Ortognáticos , Cirugía Asistida por Computador , Tecnología Digital , Humanos , Imagenología Tridimensional , Maxilar/diagnóstico por imagen , Maxilar/cirugía , Tomografía Computarizada Espiral
4.
Int J Oral Maxillofac Implants ; 36(3): 442-449, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34115056

RESUMEN

PURPOSE: To investigate the effect of implant angulation, non-free-end partial edentulism, and number of scan bodies on the accuracy of digital impressions of multiple implants in partially edentulous arches. MATERIALS AND METHODS: Four reference models of partially edentulous mandibles with implants (RM1, RM2, RM3, and RM4) representing different intraoral situations were each scanned 10 times by an intraoral scanner. Reference scans were obtained by a laboratory scanner. Test scans were compared with reference scans to obtain the distance deviations (Δd) and angular deviations (Δθ) between scan bodies for trueness assessment. Differences among the repeated test scans of each model were measured and recorded as Δdp and Δθp for precision assessment. The Student t test (α = .05) was used to compare Δd, Δθ, Δdp, and Δθp of different reference models, including RM2 vs RM1 (effect of non-free-end partial edentulism), RM3 vs RM1 (effect of implant angulation), and RM4 vs RM1 (effect of number of scan bodies). RESULTS: The implant with 17-degree angulation in RM3 showed significantly lower Δd, Δθ, and Δθp compared with the parallel implant in RM1 (Δd: P = .0382, Δθ: P = .0267, Δθp: P = .0417). The RM2 of non-free-end partial edentulism had lower distance and angular deviations than RM1, but without a significant difference. The number of scan bodies had no significant effect on the Δd, Δθ, Δdp, and Δθp of RM4 and RM1. CONCLUSION: Angulated implants showed better accuracy of digital impressions in partially edentulous arches compared with parallel implants. Non-free-end partial edentulism was attributed to improved accuracy, while the number of scan bodies showed no effect.


Asunto(s)
Implantes Dentales , Boca Edéntula , Diseño Asistido por Computadora , Técnica de Impresión Dental , Modelos Dentales , Humanos , Imagenología Tridimensional
5.
J Biomed Nanotechnol ; 17(5): 952-959, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-34082880

RESUMEN

Image registration technology is a key technology used in the process of nanomaterial imaging-aided diagnosis and targeted therapy effect monitoring for abdominal diseases. Recently, the deep-learning based methods have been increasingly used for large-scale medical image registration, because their iteration is much less than those of traditional ones. In this paper, a coarse-to-fine unsupervised learning-based three-dimensional (3D) abdominal CT image registration method is presented. Firstly, an affine transformation was used as an initial step to deal with large deformation between two images. Secondly, an unsupervised total loss function containing similarity, smoothness, and topology preservation measures was proposed to achieve better registration performances during convolutional neural network (CNN) training and testing. The experimental results demonstrated that the proposed method severally obtains the average MSE, PSNR, and SSIM values of 0.0055, 22.7950, and 0.8241, which outperformed some existing traditional and unsupervised learning-based methods. Moreover, our method can register 3D abdominal CT images with shortest time and is expected to become a real-time method for clinical application.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Nanoestructuras , Imagenología Tridimensional , Redes Neurales de la Computación , Tecnología
6.
Int J Comput Dent ; 24(2): 117-123, 2021 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-34085497

RESUMEN

AIM: A technique for merging digital intraoral and CBCT scans for implant-supported complete-arch fixed dental prostheses (FDPs) is described. The aim is to improve the dimensional accuracy of intraoral scans in edentulous arches. MATERIALS AND METHOD: Two files are recorded: an intraoral scan and a CBCT scan, both obtained with scan bodies connected to the implants in the same position. The intraoral scan is then divided into several fragments and realigned, taking as reference the position of the implants recorded in the CBCT file. RESULTS: An improved intraoral digital model with corrected implant positions appropriate for complete-arch implant FDPs is generated. CONCLUSION: The methodology proposed can minimize possible intraoral scanning error and deliver more reliable digital impressions for implant-supported complete-arch FDPs.


Asunto(s)
Implantes Dentales , Tomografía Computarizada de Haz Cónico Espiral , Diseño Asistido por Computadora , Técnica de Impresión Dental , Modelos Dentales , Humanos , Imagenología Tridimensional
7.
Int J Comput Dent ; 24(2): 157-164, 2021 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-34085501

RESUMEN

AIM: Dental research involves variations between actual and reference datasets of master models to determine the metric accuracy through transfer accuracy tests. Various methods of measurement are used to analyze the results, which are often subjected to direct comparisons. Hence, the aim of the present study was to analyze the influence and effect on results of different methods of digital data analysis, being coordinate-based analysis (CBA) and best-fit superimposition analysis. MATERIALS AND METHODS: A model with four implants and a reference cuboid was digitized through computed tomography (CT), which served as the master model. Ten implant impressions were made using a Trios (3Shape) intraoral scanner, and three different scan bodies (nt-trading, Kulzer, and Medentika) were used. The deviations between the master model and the digital impressions were analyzed using CBA and best-fit superimposition analysis. Statistical analysis was performed using SPSS 25. RESULTS: The deviations in the CBA and best-fit superimposition analysis ranged from 0.088 ± 0.012 mm (mean ± SE; Medentika, 14) to 0.199 ± 0.021 mm (Kulzer, 26), and from 0.042 ± 0.010 mm (Medentika, 16) to 0.074 ± 0.006 mm (Kulzer, 16), respectively. Significant differences were observed between the implant positions in the CBA and the digital measurements at each implant position, whereas the best-fit analysis showed no significant difference between the scan bodies and implant positions. CONCLUSION: CBA displays an advantage over best-fit superimposition analysis in the detection of possible influencing factors for primarily scientific purposes. However, a global analysis and visualization of angles and torsions is difficult, for which a best-fit evaluation is needed. However, a best-fit analysis better represents the clinical try-in. It is associated with the risk that possible disturbing factors and resulting errors might be leveled out and their identification camouflaged.


Asunto(s)
Implantes Dentales , Técnica de Impresión Dental , Diseño Asistido por Computadora , Análisis de Datos , Materiales de Impresión Dental , Modelos Dentales , Humanos , Imagenología Tridimensional
8.
Comput Methods Programs Biomed ; 206: 106117, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34022696

RESUMEN

BACKGROUND AND OBJECTIVE: Liver tumor ablation is often guided by ultrasound (US). Due to poor image quality, intraoperative US is fused with preoperative computed tomography or magnetic tomography (CT/MR) images to provide visual guidance. As of today, the underlying 2D US to 3D CT/MR registration problem remains a very challenging task. METHODS: We propose a novel pipeline to address this registration problem. Contrary to previous work, we do not formulate the problem as a regression task, which - for the given registration problem - achieves a low performance regarding accuracy and robustness due to the limited US soft-tissue contrast and the inter-patient variability on liver vessels. Instead, we first estimate the US probe angle roughly by using a classification network. Given this coarse initialization, we then improve the registration by formulation of the problem as a segmentation task, estimating the US plane in the 3D CT/MR through segmentation. RESULTS: We benchmark our approach on 1035 clinical images from 52 patients, yielding average registration errors of 11.6° and 4.7 mm, which outperforms the state of the art SVR method[1]. CONCLUSION: Our results show the efficiency of the proposed registration pipeline, which has potential to improve the robustness and accuracy of intraoperative patient registration.


Asunto(s)
Aprendizaje Profundo , Neoplasias Hepáticas , Humanos , Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Neoplasias Hepáticas/diagnóstico por imagen , Neoplasias Hepáticas/cirugía , Tomografía Computarizada por Rayos X , Ultrasonografía
9.
Nat Commun ; 12(1): 3067, 2021 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-34031389

RESUMEN

Diffractive optical elements (DOEs) are used to shape the wavefront of incident light. This can be used to generate practically any pattern of interest, albeit with varying efficiency. A fundamental challenge associated with DOEs comes from the nanoscale-precision requirements for their fabrication. Here we demonstrate a method to controllably scale up the relevant feature dimensions of a device from tens-of-nanometers to tens-of-microns by immersing the DOEs in a near-index-matched solution. This makes it possible to utilize modern 3D-printing technologies for fabrication, thereby significantly simplifying the production of DOEs and decreasing costs by orders of magnitude, without hindering performance. We demonstrate the tunability of our design for varying experimental conditions, and the suitability of this approach to ultrasensitive applications by localizing the 3D positions of single molecules in cells using our microscale fabricated optical element to modify the point-spread-function (PSF) of a microscope.


Asunto(s)
Inmersión , Dispositivos Ópticos , Impresión Tridimensional , Imagenología Tridimensional/métodos , Microscopía Fluorescente/métodos , Nanotecnología , Impresión Tridimensional/instrumentación , Sensibilidad y Especificidad
10.
Med Sci Monit ; 27: e930435, 2021 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-33947821

RESUMEN

BACKGROUND The anatomy of the coracoid process and coracoclavicular (CC) ligament have been described and the correlation between them has been assessed based on 3-dimensional computed tomography (CT) reconstruction and magnetic resonance imaging (MRI), which provide a guide for coracoclavicular ligament reconstruction. MATERIAL AND METHODS Data were collected from 300 patients who underwent both CT and MRI of the shoulder joint from January 2017 to January 2019 at the Jiang'an Hospital of Traditional Chinese Medicine. The coracoid process was observed and classified and parameters of the CC ligament were measured according to different corneal types. All of the statistics were collected and classified by 2 radiologists, and average values were determined.Measurements of segments were taken as follows: ab - In the coronal plane, the length of the CC ligament from the central point of the CC ligament at the clavicular attachment to the CC ligament at the center of the CC attachment); ac - The distance from the center point of the CC ligament at the supraclavicular attachment to the acromioclavicular joint; de - In the sagittal plane, the length of the CC ligament from the center of the clavicular attachment to the coracoid attachment point; fg - The maximum diameter of the CC ligament at the anterior and posterior margins of the clavicle attachment; hi - The largest diameter of the CC ligament at the anterior and posterior edge of the coracoid process attachment; dj - The distance of the coracoclavicular ligament from the center point of the coracoid process attachment to the coracoid process tip; kl - The distance in the supraclavicular plane from the coracoclavicular ligament to the subcoracoid process. RESULTS The analysis showed that there are 5 types of coracoid process: gourd (31%), short rod (20%), long rod (22.3%), wedge (10.3%), and water drop (6.3%). There were statistically significant differences between the lengths of the ac and hi segments in the among the wedge and gourd-type and the short rod and water drop-type coracoid processes. There were statistically significant differences between the lengths of the ab, de, and fg segments in the short rod, gourd, and long rod-type coracoid processes. There were statistically significant differences between the lengths of the ac, fg, hi, dj, and kl segments in the water drop, gourd, and long rod-type coracoid processes. CONCLUSIONS The present study indicated that measurement of the CC ligament and the different shapes of the coracoid process provide an anatomical basis for the diagnosis and treatment of shoulder diseases and the data can be used to improve the safety of CC ligament reconstruction.


Asunto(s)
Apófisis Coracoides/anatomía & histología , Apófisis Coracoides/cirugía , Ligamentos Articulares/anatomía & histología , Ligamentos Articulares/cirugía , Articulación Acromioclavicular/anatomía & histología , Articulación Acromioclavicular/cirugía , Adulto , Clavícula/anatomía & histología , Clavícula/cirugía , Femenino , Humanos , Imagenología Tridimensional/métodos , Imagen por Resonancia Magnética/métodos , Masculino , Estudios Retrospectivos , Articulación del Hombro/anatomía & histología , Articulación del Hombro/cirugía , Tomografía Computarizada por Rayos X/métodos
11.
Nat Commun ; 12(1): 2921, 2021 05 19.
Artículo en Inglés | MEDLINE | ID: mdl-34012021

RESUMEN

Spatial light modulators have become an essential tool for advanced microscopy, enabling breakthroughs in 3D, phase, and super-resolution imaging. However, continuous spatial-light modulation that is capable of capturing sub-millisecond microscopic motion without diffraction artifacts and polarization dependence is challenging. Here we present a photothermal spatial light modulator (PT-SLM) enabling fast phase imaging for nanoscopic 3D reconstruction. The PT-SLM can generate a step-like wavefront change, free of diffraction artifacts, with a high transmittance and a modulation efficiency independent of light polarization. We achieve a phase-shift > π and a response time as short as 70 µs with a theoretical limit in the sub microsecond range. We used the PT-SLM to perform quantitative phase imaging of sub-diffractional species to decipher the 3D nanoscopic displacement of microtubules and study the trajectory of a diffusive microtubule-associated protein, providing insights into the mechanism of protein navigation through a complex microtubule network.


Asunto(s)
Microscopía de Contraste de Fase/métodos , Proteínas de Ciclo Celular/metabolismo , Simulación por Computador , Oro , Humanos , Imagenología Tridimensional/métodos , Imagenología Tridimensional/estadística & datos numéricos , Luz , Nanopartículas del Metal/ultraestructura , Microscopía de Fuerza Atómica , Microscopía de Interferencia/métodos , Microscopía de Interferencia/estadística & datos numéricos , Microscopía de Contraste de Fase/estadística & datos numéricos , Proteínas Asociadas a Microtúbulos/metabolismo , Microtúbulos/metabolismo , Microtúbulos/ultraestructura , Nanotecnología , Nanotubos/ultraestructura , Fenómenos Ópticos , Proteínas de Schizosaccharomyces pombe/metabolismo , Factores de Tiempo , Tubulina (Proteína)/metabolismo
12.
Eur J Radiol ; 140: 109739, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33945922

RESUMEN

OBJECTIVE: To compare the image quality of VIBE sequence using controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA-VIBE) and using generalized autocalibrating partially parallel acquisitions (GRAPPA-VIBE) in liver magnetic resonance examination, and to evaluate the effect of non-rigid 3D-registration motion correction (MOCO) combined with CAIPIRINHA-VIBE on liver spatial location registration. METHODS: A total of 85 patients underwent pre-contrast GRAPPA-VIBE and CAIPIRINHA-VIBE breath-hold scan in the mask phase, and then underwent CAIPIRINHA-VIBE breath-hold scan in arterial phase, portal vein phase and delay phase after administration. After the scanning of four phases of CAIPIRINHA-VIBE completed, 3D images without and with MOCO of each phase were automatically generated. The images quality of GRAPPA-VIBE and CAIPIRINHA-VIBE without MOCO in the mask phase was scored subjectively by two physicians. The number of slices at the top of the diaphragm in the arterial phase was taken as the base slice, and that in the other stages subtracted with the base slice for CAIPIRINHA without and with MOCO. The range of diaphragm movement in each phase was counted by + N/- N statistics. RESULTS: The image quality and the scores of CAIPIRINHA-VIBE were significantly higher than those of GRAPPA-VIBE in respiratory motion artifact suppression, liver edge sharpness and intrahepatic vascular sharpness (p < 0.05). The spatial position consistency of the liver with MOCO is significantly better than that without MOCO. CONCLUSION: CAIPIRINHA-VIBE with MOCO can be used instead of conventional GRAPPA-VIBE sequence in upper abdominal MRI enhancement examination, especially for patients with poor breath-hold.


Asunto(s)
Medios de Contraste , Aumento de la Imagen , Aceleración , Artefactos , Contencion de la Respiración , Humanos , Imagenología Tridimensional , Hígado/diagnóstico por imagen , Imagen por Resonancia Magnética , Espectroscopía de Resonancia Magnética , Reproducibilidad de los Resultados
13.
Eur J Radiol ; 140: 109738, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33945923

RESUMEN

PURPOSE: Increasing economic pressure and patient demands for comfort require an ever-increasing acceleration of scan times without compromising diagnostic certainty. This study tested the new acceleration technique Compressed SENSE (CS-SENSE) as well as different reconstruction methods for the lumbar spine. METHODS: In this prospective study, 10 volunteers and 14 patients with lumbar disc herniation were scanned using a sagittal 2D T2 turbo spin echo (TSE) sequence applying different acceleration factors of SENSE and CS-SENSE. Gradient echo (GRE), autocalibration (CS-Auto) and TSE prescans were tested for reconstruction. Images were analysed by two readers regarding anatomical delineation, diagnostic certainty (for patients only) and image quality as well as objectively calculating the root mean square error (RMSE), structural similarity index (SSIM), SNR and CNR. The Friedman test and Chi-squared were used for ordinal, ANOVA for repeated measurements and Tukey Kramer test for continuous data. Cohen's kappawas calculated for interreader reliability. RESULTS: CS-SENSE outperformed SENSE and CS-Auto regarding RMSE (e.g. CS-SENSE 1.5: 43.03 ±â€¯11.64 versus SENSE 1.5: 80.41 ±â€¯17.66; p = 0.0038) and SSIM as well as in the subjective rating for CS-SENSE 3 TSE. In the patient setting image quality was unchanged in all subjective criteria up to CS-SENSE 3 TSE (all p > 0.05) compared to standard T2 with 43 % less scan time while the GRE prescan only allowed a reduction of 32 %. CONCLUSION: Combining a TSE prescan with CS-SENSE enables significant scan time reductions with unchanged ratings for lumbar spine disc herniation making this superior to the currently used SENSE acceleration or GRE reconstructions.


Asunto(s)
Imagenología Tridimensional , Desplazamiento del Disco Intervertebral , Humanos , Desplazamiento del Disco Intervertebral/diagnóstico por imagen , Imagen por Resonancia Magnética , Estudios Prospectivos , Reproducibilidad de los Resultados
14.
Nat Commun ; 12(1): 2583, 2021 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-33972516

RESUMEN

Quantitative micromechanical characterization of single cells and multicellular tissues or organisms is of fundamental importance to the study of cellular growth, morphogenesis, and cell-cell interactions. However, due to limited manipulation capabilities at the microscale, systems used for mechanical characterizations struggle to provide complete three-dimensional coverage of individual specimens. Here, we combine an acoustically driven manipulation device with a micro-force sensor to freely rotate biological samples and quantify mechanical properties at multiple regions of interest within a specimen. The versatility of this tool is demonstrated through the analysis of single Lilium longiflorum pollen grains, in combination with numerical simulations, and individual Caenorhabditis elegans nematodes. It reveals local variations in apparent stiffness for single specimens, providing previously inaccessible information and datasets on mechanical properties that serve as the basis for biophysical modelling and allow deeper insights into the biomechanics of these living systems.


Asunto(s)
Imagenología Tridimensional/métodos , Micromanipulación/instrumentación , Micromanipulación/métodos , Microscopía de Fuerza Atómica/métodos , Análisis de la Célula Individual/instrumentación , Análisis de la Célula Individual/métodos , Acústica , Animales , Fenómenos Biomecánicos , Caenorhabditis elegans/anatomía & histología , Caenorhabditis elegans/citología , Pared Celular/ultraestructura , Lilium/citología , Microscopía Electrónica de Rastreo , Morfogénesis , Células Vegetales , Polen/citología , Polen/ultraestructura
15.
J Vis Exp ; (170)2021 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-33938881

RESUMEN

Structure-from-motion (SfM) photogrammetry is a technique used to generate three-dimensional (3D) reconstructions from a sequence of two-dimensional (2D) images. SfM methods are becoming increasingly popular as a noninvasive way to monitor many systems, including anthropogenic and natural landscapes, geologic structures, and both terrestrial and aquatic ecosystems. Here, a detailed protocol is provided for collecting SfM imagery to generate 3D models of benthic habitats. Additionally, the cost, time efficiency, and output quality of employing a Digital Single Lens Reflex (DSLR) camera versus a less expensive action camera have been compared. A tradeoff between computational time and resolution was observed, with the DSLR camera producing models with more than twice the resolution, but taking approximately 1.4-times longer to produce than the action camera. This primer aims to provide a thorough description of the steps necessary to collect SfM data in benthic habitats for those who are unfamiliar with the technique as well as for those already using similar methods.


Asunto(s)
Ecosistema , Imagenología Tridimensional/métodos , Fotogrametría
16.
J Vis Exp ; (170)2021 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-33938887

RESUMEN

Orthodontic tooth movement is a complex biological process of altered soft and hard tissue remodeling as a result of external forces. In order to understand these complex remodeling processes, it is critical to study the tooth and periodontal tissues within their 3D context and therefore minimize any sectioning and tissue artefacts. Mouse models are often utilized in developmental and structural biology, as well as in biomechanics due to their small size, high metabolic rate, genetics and ease of handling. In principle this also makes them excellent models for dental related studies. However, a major impediment is their small tooth size, the molars in particular. This paper is aimed at providing a step by step protocol for generating orthodontic tooth movement and two methods for 3D imaging of the periodontal ligament fibrous component of a mouse mandibular molar. The first method presented is based on a micro-CT setup enabling phase enhancement imaging of fresh collagen tissues. The second method is a bone clearing method using ethyl cinnamate that enables imaging through the bone without sectioning and preserves endogenous fluorescence. Combining this clearing method with reporter mice like Flk1-Cre;TdTomato provided a first of its kind opportunity to image the 3D vasculature in the PDL and alveolar bone.


Asunto(s)
Imagenología Tridimensional/métodos , Mandíbula/diagnóstico por imagen , Diente Molar/diagnóstico por imagen , Ligamento Periodontal/diagnóstico por imagen , Técnicas de Movimiento Dental , Animales , Fenómenos Biomecánicos , Cinamatos , Modelos Animales de Enfermedad , Ratones , Microtomografía por Rayos X/métodos
17.
Biomed Res Int ; 2021: 5585629, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33997021

RESUMEN

Purpose: Obstructive sleep apnea is a condition involving repetitive partial or complete collapse of the pharyngeal airway, especially in patient with mandibular hypoplasia. The present study investigated the differences between the volume of the oropharyngeal airway and the minimum axial area in three skeletal patterns through the use of cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans of 147 patients were collected to measure the upper oropharyngeal airway volume (UOV), lower oropharyngeal airway volume (LOV), upper oropharyngeal airway area (UOA), minimum upper oropharyngeal airway area (MUOA), lower oropharyngeal airway area (LOA), minimum lower oropharyngeal airway area (MLOA), anatomical structures (orbitale, Or; porion, Po; pogonion, Pog; hyoid, H; second cervical vertebra, C2; fourth cervical vertebra, C4), and relevant angles. Statistical analysis was performed using analysis of variance and Pearson's test. Results: Compared with patients in Class II, those in Class III and Class I exhibited a significantly anterior position of H and Pog. The vertical positions of H and Pog revealed no significant difference between the three skeletal patterns. Patients in skeletal Class III exhibited significantly larger oropharyngeal area (UOA, MUOA, LOA, MLOA) and oropharyngeal airway (UOV and LOV) than those in skeletal Class II did. The horizontal position of Pog had a moderately significant correlation with UOA (r = 0.471) and MUOA (r = 0.455). Conclusion: Patients in skeletal Class II had significantly smaller oropharyngeal airway areas and volumes than those in Class III did. The minimum oropharyngeal cross-sectional area had a 67% probability of occurrence in the upper oropharyngeal airway among patients in Class I and Class II and a 50% probability of occurrence among patients in Class III.


Asunto(s)
Huesos/diagnóstico por imagen , Tomografía Computarizada de Haz Cónico , Orofaringe/diagnóstico por imagen , Adulto , Análisis de Varianza , Puntos Anatómicos de Referencia , Huesos/anatomía & histología , Femenino , Humanos , Imagenología Tridimensional , Masculino , Orofaringe/anatomía & histología , Adulto Joven
18.
Adv Exp Med Biol ; 1317: 53-74, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33945132

RESUMEN

Forensic craniofacial identification encompasses the practices of forensic facial approximation (aka facial reconstruction) and craniofacial superimposition within the field of forensic art in the United States. Training in forensic facial approximation methods historically has used plaster copies, high-cost commercially molded skulls, and photographs. Despite the increased accessibility of computed tomography (CT) and the numerous studies utilizing CT data to better inform facial approximation methods, 3D CT data have not yet been widely used to produce interactive resources or reference catalogs aimed at forensic art practitioner use or method standardization. There are many free, open-source 3D software packages that allow engagement in immersive studies of the relationships between the craniofacial skeleton and facial features and facilitate collaboration between researchers and practitioners. 3D CT software, in particular, allows the bone and soft tissue to be visualized simultaneously with tools such as transparency, clipping, and volume rendering of underlying tissues, allowing for more accurate analyses of bone to soft tissue relationships. Analyses and visualization of 3D CT data can not only facilitate basic research into facial variation and anatomical relationships relevant for reconstructions but can also lead to improved facial reconstruction guidelines. Further, skull and face surface models exported in digital 3D formats allow for 3D printing of custom reference models and novel training materials and modalities for practitioners. This chapter outlines the 3D resources that can be built from CT data for forensic craniofacial identification methods, including how to view 3D craniofacial CT data and modify surface models for 3D printing.


Asunto(s)
Imagenología Tridimensional , Tomografía Computarizada por Rayos X , Cara/diagnóstico por imagen , Medicina Legal , Cráneo/diagnóstico por imagen
19.
Bone Joint J ; 103-B(5): 931-938, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33934640

RESUMEN

AIMS: The morphology of medial malleolar fracture is highly variable and difficult to characterize without 3D reconstruction. There is also no universally accepeted classification system. Thus, we aimed to characterize fracture patterns of the medial malleolus and propose a classification scheme based on 3D CT reconstruction. METHODS: We retrospectively reviewed 537 consecutive cases of ankle fractures involving the medial malleolus treated in our institution. 3D fracture maps were produced by superimposing all the fracture lines onto a standard template. We sliced fracture fragments and the standard template based on selected sagittal and coronal planes to create 2D fracture maps, where angles α and ß were measured. Angles α and ß were defined as the acute angles formed by the fracture line and the horizontal line on the selected planes. RESULTS: A total of 121 ankle fractures were included. We revealed several important fracture features, such as a high correlation between posterior collicular fractures and posteromedial fragments. Moreover, we generalized the fracture geometry into three recurrent patterns on the coronal view of 3D maps (transverse, vertical, and irregular) and five recurrent patterns on the lateral view (transverse, oblique, vertical, Y-shaped, and irregular). According to the fracture geometry on the coronal and lateral view of 3D maps, we subsequently categorized medial malleolar fractures into six types based on the recurrent patterns: anterior collicular fracture (27 type I, 22.3%), posterior collicular fracture (12 type II, 9.9%), concurrent fracture of anterior and posterior colliculus (16 type III, 13.2%), and supra-intercollicular groove fracture (66 type IV, 54.5%). Therewere three variants of type IV fractures: transverse (type IVa), vertical (type IVb), and comminuted fracture (type IVc). The angles α and ß varied accordingly. CONCLUSION: Our findings yield insight into the characteristics and recurrent patterns of medial malleolar fractures. The proposed classification system is helpful in understanding injury mechanisms and guiding diagnosis, as well as surgical strategies. Cite this article: Bone Joint J 2021;103-B(5):931-938.


Asunto(s)
Fracturas de Tobillo/clasificación , Fracturas de Tobillo/diagnóstico por imagen , Imagenología Tridimensional , Tomografía Computarizada por Rayos X/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos
20.
Int J Comput Dent ; 24(1): 9-17, 2021 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-34006059

RESUMEN

AIM: The transfer of 3D implant position planning to the clinical site is challenging. The aim of this study was to compare in vitro this transfer accuracy by using dynamic real-time navigation or static surgical guides. MATERIALS AND METHODS: Deviations between planned and actual pilot drill positions were calculated (Denacam and NobelGuide; each n = 90), matching pre- and postoperative CBCT images: entry point, angle, tip (each 3D); depth, mesiodistal/bucco-oral entry points, and angles (each 1D). The influence of the maxilla and mandible, implant region (anterior/posterior), and marker position (ipsilateral/contralateral, Denacam only) was investigated (Mann-Whitney U test). RESULTS: No significant differences occurred regarding entry point (3D), mesiodistal/bucco-oral entry points (1D) or mesiodistal angle (1D) (P > 0.05). The angular and tip deviations (3D) were significantly smaller using Denacam (2.16 ± 0.59 degrees, 0.80 ± 0.55 mm; NobelGuide 2.54 ± 1.19 degrees, 1.09 ± 0.56 mm; P = 0.024, P < 0.0001). The deviations in depth and bucco-oral angle (1D) were significantly smaller using NobelGuide (1.05 ± 0.50 mm, 1.02 ± 1.16 degrees; Denacam 1.50 ± 0.64 mm, 1.51 ± 0.82 degrees; P < 0.0001). Significantly smaller deviations occurred within the mandible (Denacam, 5/8 parameters). Region and marker position showed no influence. No distinct influences were found with the use of NobelGuide. CONCLUSION: Denacam might possibly be a promising alternative to static surgical guides.


Asunto(s)
Implantes Dentales , Cirugía Asistida por Computador , Diseño Asistido por Computadora , Tomografía Computarizada de Haz Cónico , Implantación Dental Endoósea , Humanos , Imagenología Tridimensional , Maxilar/cirugía
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