Identifying and documenting osseous trauma from shark attacks by post mortem CT examination and autopsy.

A 15-year-old male was attacked by a large white shark while surfing. CT examination revealed an above-knee amputation of the right lower extremity with stripping of soft tissues from the groin distally. 3-dimensional volume rendering did not show any fragments of shark teeth but did reveal linear gouges, areas of shaving of cortical bone and an inverted 'V'-shaped defect at the distal margin of the femoral shaft. At autopsy these injuries were confirmed in addition to areas with fine parallel cross-striations matching the marginal serrations of the teeth of a white shark. Thus, while post mortem CT with 3-dimensional reconstruction at high resolution can show the nature and number of the bony injuries following shark attack, it is complimented by pathological examination which may find fine parallel grooves from teeth serrations. Post mortem 3-dimensional volume rendering may also help to find or exclude fragments of teeth, and silicone casting may provide a permanent record of bone lesions.

3D Echocardiogram Visualization: A New Method Based on "Focus + Context".

3D echocardiography (3DE) is the standard modality for visualizing heart valves and their surrounding anatomical structures. Commercial cardiovascular ultrasound systems commonly offer a set of parameters that allow clinical users to modify, in real time, visual aspects of the information contained in the echocardiogram. To our knowledge, there is currently no work that demonstrates if the methods currently used by commercial platforms are optimal. In addition, current platforms have limitations in adjusting the visibility of anatomical structures, such as reducing information that obstructs anatomical structures without removing essential clinical information. To overcome this, the present work proposes a new method for 3DE visualization based on "focus + context" (F+C), a concept which aims to present a detailed region of interest while preserving a less detailed overview of the surrounding context. The new method is intended to allow clinical users to modify parameter values differently within a certain region of interest, independently from the adjustment of contextual information. To validate this new method, a user study was conducted amongst clinical experts. As part of the user study, clinical experts adjusted parameters for five echocardiograms of patients with complete atrioventricular canal defect (CAVC) using both the method conventionally used by commercial platforms and the proposed method based on F+C. The results showed relevance for the F+C-based method to visualize 3DE of CAVC patients, where users chose significantly different parameter values with the F+C-based method.

Cascade spatial and channel-wise multifusion network with criss cross augmentation for corneal segmentation and reconstruction.

High-quality 3D corneal reconstruction from AS-OCT images has demonstrated significant potential in computer-aided diagnosis, enabling comprehensive observation of corneal thickness, precise assessment of morphological characteristics, as well as location and quantification of keratitis-affected regions. However, it faces two main challenges: (1) prevalent medical image segmentation networks often struggle to accurately process low-contrast corneal regions, which is a vital pre-processing step for 3D corneal reconstruction, and (2) there are no reconstruction methods that can be directly applied to AS-OCT sequences with 180-degree scanning. To combat these, we propose CSCM-CCA-Net, a simple yet efficient network for accurate corneal segmentation. This network incorporates two key techniques: cascade spatial and channel-wise multifusion (CSCM), which captures intricate contextual interdependencies and effectively extracts low-contrast and obscure corneal features; and criss cross augmentation (CCA), which enhances shape-preserved feature representation to improve segmentation accuracy. Based on the obtained corneal segmentation results, we reconstruct the 3D volume data and generate a topographic map of corneal thickness through corneal image alignment. Additionally, we design a transfer function based on the analysis of intensity histogram and gradient histogram to explore more internal cues for better visualization results. Experimental results on CORNEA benchmark demonstrate the impressive performance of our proposed method in terms of both corneal segmentation and 3D reconstruction. Furthermore, we compare CSCM-CCA-Net with state-of-the-art medical image segmentation approaches using three challenging medical fundus segmentation datasets (DRIVE, CHASEDB1, FIVES), highlighting its superiority in terms of segmentation accuracy. The code and models will be made available at https://github.com/qianguiping/CSCM-CCA-Net.

An optimized CT-dense agent perfusion and micro-CT imaging protocol for chick embryo developmental stages.

Compared to classical techniques of morphological analysis, micro-CT (µ-CT) has become an effective approach allowing rapid screening of morphological changes. In the present work, we aimed to provide an optimized micro-CT dense agent perfusion protocol and µ-CT guidelines for different stages of chick embryo cardiogenesis. Our study was conducted over a period of 10 embryonic days (Hamburger-Hamilton HH36) in chick embryo hearts. During the perfusion of the micro-CT dense agent at different developmental stages (HH19, HH24, HH27, HH29, HH31, HH34, HH35, and HH36), we demonstrated that durations and volumes of the injected contrast agent gradually increased with the heart developmental stages contrary to the flow rate that was unchanged during the whole experiment. Analysis of the CT imaging confirmed the efficiency of the optimized parameters of the heart perfusion.

A System for Mixed-Reality Holographic Overlays of Real-Time Rendered 3D-Reconstructed Imaging Using a Video Pass-through Head-Mounted Display-A Pathway to Future Navigation in Chest Wall Surgery.

Background: Three-dimensional reconstructions of state-of-the-art high-resolution imaging are progressively being used more for preprocedural assessment in thoracic surgery. It is a promising tool that aims to improve patient-specific treatment planning, for example, for minimally invasive or robotic-assisted lung resections. Increasingly available mixed-reality hardware based on video pass-through technology enables the projection of image data as a hologram onto the patient. We describe the novel method of real-time 3D surgical planning in a mixed-reality setting by presenting three representative cases utilizing volume rendering. Materials: A mixed-reality system was set up using a high-performance workstation running a video pass-through-based head-mounted display. Image data from computer tomography were imported and volume-rendered in real-time to be customized through live editing. The image-based hologram was projected onto the patient, highlighting the regions of interest. Results: Three oncological cases were selected to explore the potentials of the mixed-reality system. Two of them presented large tumor masses in the thoracic cavity, while a third case presented an unclear lesion of the chest wall. We aligned real-time rendered 3D holographic image data onto the patient allowing us to investigate the relationship between anatomical structures and their respective body position. Conclusions: The exploration of holographic overlay has proven to be promising in improving preprocedural surgical planning, particularly for complex oncological tasks in the thoracic surgical field. Further studies on outcome-related surgical planning and navigation should therefore be conducted. Ongoing technological progress of extended reality hardware and intelligent software features will most likely enhance applicability and the range of use in surgical fields within the near future.

Enhancing View Synthesis with Depth-Guided Neural Radiance Fields and Improved Depth Completion.

Neural radiance fields (NeRFs) leverage a neural representation to encode scenes, obtaining photorealistic rendering of novel views. However, NeRF has notable limitations. A significant drawback is that it does not capture surface geometry and only renders the object surface colors. Furthermore, the training of NeRF is exceedingly time-consuming. We propose Depth-NeRF as a solution to these issues. Specifically, our approach employs a fast depth completion algorithm to denoise and complete the depth maps generated by RGB-D cameras. These improved depth maps guide the sampling points of NeRF to be distributed closer to the scene's surface, benefiting from dense depth information. Furthermore, we have optimized the network structure of NeRF and integrated depth information to constrain the optimization process, ensuring that the termination distribution of the ray is consistent with the scene's geometry. Compared to NeRF, our method accelerates the training speed by 18%, and the rendered images achieve a higher PSNR than those obtained by mainstream methods. Additionally, there is a significant reduction in RMSE between the rendered scene depth and the ground truth depth, which indicates that our method can better capture the geometric information of the scene. With these improvements, we can train the NeRF model more efficiently and achieve more accurate rendering results.

Comparison of two 3D reconstruction models for understanding of complicated female pelvic tumors.

OBJECTIVE: Three-dimensional (3D) reconstructed models have been shown to improve visualization in complex female pelvic tumors. Cinematic rendering (CR) is a 3D imaging technique for computed tomography (CT) images, which creates more realistic images with the ability to enhance imaging of anatomical features for diagnosis. This study was set up to compare two types of 3D models and to validate the use of 3D anatomical techniques for the diagnosis of complex female pelvic tumors. METHODS: The preclinical, randomized, two-sequence crossover investigation was performed from December 2022 to January 2023 at First Affiliated Hospital of Chongqing Medical University. Sixteen residents and 10 attending surgeons assessed the cases of 23 patients with two types of 3D model images. The surgeons were randomly assigned to two assessment sequences (CR-3D model group and CT-3D model group). For each case, participants selected one question that probed fundamental questions about the tumor's genesis throughout each assessment period. Following a 4-week washout period, case assessments were transferred to the other image modality. RESULTS: The main result assessment was the accuracy of the answers. The time to answer the questions and the case assessment questionnaire was added as a secondary outcome. The mean scores in the CR-3D models (19.35 ± 1.87) varied significantly from those in the CT-CR group (16.77 ± 1.8) (P < 0.001), and solving the questions in the CT-3D model sequence (41.96 ± 6.31 s) varied significantly from that in the CR-3D model sequence (52.88 ± 5.95 s) (P < 0.001). Subgroup analysis revealed that there were statistically significant variations in the scores of female reproductive tumors, pelvic tumors other than the reproductive system, and retroperitoneal tumors (P = 0.005). Analysis of the assessment questionnaire showed that more surgeons choose CR 3D reconstruction (8.31 ± 0.76 vs 7.15 ± 1.19, P < 0.001). CONCLUSIONS: The results suggest that each 3D reconstruction method has its own advantages. Surgeons feel that CR reconstruction models are a useful technique that can improve their comprehension of complex pelvic tumors, while traditional 3D models have an advantage in terms of speed to diagnosis.

Accuracy of solid portion size measured on multiplanar volume rendering images for assessing invasiveness in lung adenocarcinoma manifesting as subsolid nodules.

Background: The solid component of subsolid nodules (SSNs) is closely associated with the invasiveness of lung adenocarcinoma, and its accurate assessment is crucial for selecting treatment method. Therefore, this study aimed to evaluate the accuracy of solid component size within SSNs measured on multiplanar volume rendering (MPVR) and compare it with the dimensions of invasive components on pathology. Methods: A pilot study was conducted using a chest phantom to determine the optimal MPVR threshold for the solid component within SSN, and then clinical validation was carried out by retrospective inclusion of patients with pathologically confirmed solitary SSN from October 2020 to October 2021. The radiological tumor size on MPVR and solid component size on MPVR (RSSm) and on lung window (RSSl) were measured. The size of the tumor and invasion were measured on the pathological section, and the invasion, fibrosis, and inflammation within SSNs were also recorded. The measurement difference between computed tomography (CT) and pathology, inter-observer and inter-measurement agreement were analyzed. Receiver operating characteristic (ROC) analysis and Bland-Altman plot were performed to evaluate the diagnostic efficiency of MPVR. Results: A total of 142 patients (mean age, 54±11 years, 39 men) were retrospectively enrolled in the clinical study, with 26 adenocarcinomas in situ, 92 minimally invasive adenocarcinomas (MIAs), and 24 invasive adenocarcinomas (IAs). The RSSl was significantly smaller than pathological invasion size with fair inter-measurement agreement [intraclass correlation coefficient (ICC) =0.562, P<0.001] and moderate interobserver agreement (ICC =0.761, P<0.001). The RSSm was significantly larger than pathological invasion size with the excellent inter-measurement agreement (ICC =0.829, P<0.001) and excellent (ICC =0.952, P<0.001) interobserver agreement. ROC analysis showed that the cutoff value of RSSm for differentiating adenocarcinoma in situ from MIA and MIA from IA was 1.85 and 6.45 mm (sensitivity: 93.8% and 95.5%, specificity: 85.7% and 88.2%, 95% confidence internal: 0.914-0.993 and 0.900-0.983), respectively. The positive predictive value-and negative predictive value of MPVR in predicting invasiveness were 92.8% and 100%, respectively. Conclusions: Using MPVR to predict the invasive degree of SSN had high accuracy and good inter-observer agreement, which is superior to lung window measurements and helpful for clinical decision-making.

Neural radiance fields-based multi-view endoscopic scene reconstruction for surgical simulation.

PURPOSE: In virtual surgery, the appearance of 3D models constructed from CT images lacks realism, leading to potential misunderstandings among residents. Therefore, it is crucial to reconstruct realistic endoscopic scene using multi-view images captured by an endoscope. METHODS: We propose an Endoscope-NeRF network for implicit radiance fields reconstruction of endoscopic scene under non-fixed light source, and synthesize novel views using volume rendering. Endoscope-NeRF network with multiple MLP networks and a ray transformer network represents endoscopic scene as implicit field function with color and volume density at continuous 5D vectors (3D position and 2D direction). The final synthesized image is obtained by aggregating all sampling points on each ray of the target camera using volume rendering. Our method considers the effect of distance from the light source to the sampling point on the scene radiance. RESULTS: Our network is validated on the lung, liver, kidney and heart of pig collected by our device. The results show that the novel views of endoscopic scene synthesized by our method outperform existing methods (NeRF and IBRNet) in terms of PSNR, SSIM, and LPIPS metrics. CONCLUSION: Our network can effectively learn a radiance field function with generalization ability. Fine-tuning the pre-trained model on a new endoscopic scene to further optimize the neural radiance fields of the scene, which can provide more realistic, high-resolution rendered images for surgical simulation.

Anatomical and Three-Dimensional Study of the Female Feline Abdominal and Pelvic Vascular System Using Dissections, Computed Tomography Angiography and Magnetic Resonance Angiography.

This study describes the anatomical characteristics of the abdominal and pelvic vascular system of two healthy mature female cats via three-dimensional contrast enhanced computed tomography angiography, non-contrast enhanced magnetic resonance angiography and three-dimensional printing. Volume-rendering computed tomography angiography images were acquired from the ventral aspect using RadiAnt, Amira and OsiriX MD Dicom three-dimensional formats, and three-dimensional printing was obtained and compared with the corresponding computed tomography angiography images. Non-contrast enhanced magnetic resonance angiography was made using the time-of-flight imaging in ventral, oblique and lateral views. In addition, three cadavers with colored latex injection were dissected to facilitate the identification of the vascular structures. Three-dimensional computed tomography angiography showed the main vascular structures, whereas with the time-of-flight blood appeared with a high signal intensity compared with associated abdominal and pelvic tissues. Three-dimensional computed tomography angiography images and time-of-flight sequences provided adequate anatomical details of the main arteries and veins that could be used for future feline anatomical and clinical vascular studies of the abdomen and pelvis.

The guiding value of the cinematic volume rendering technique in the preoperative diagnosis of brachial plexus schwannoma.

This study aimed to explore and compare the guiding value of Maximum Intensity Projection (MIP) and Cinematic Volume Rendering Technique (cVRT) in the preoperative diagnosis of brachial plexus schwannomas. We retrospectively analyzed the clinical and imaging data of 45 patients diagnosed with brachial plexus schwannomas at the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2022. The enhanced three-dimensional short recovery time inversion-recovery fast spin-echo imaging (3D-STIR-SPACE) sequence served as source data for the reconstruction of MIP and cVRT. Two independent observers scored the image quality and evaluated the location of the tumor and the relationship between the tumor and the brachial plexus. The image quality scores of the two reconstruction methods were compared using the nonparametric Wilcoxon signed-rank test, and the consistency between the image and surgical results was assessed using the weighted kappa. Compared to MIP images, cVRT images had a better performance of overall image quality (p < 0.001), nerve and lump visualization (p < 0.001), spatial positional relationship conspicuity (p < 0.001), and diagnostic confidence (p < 0.001). Additionally, the consistency between the cVRT image results and surgical results (kappa =0.913, P<0.001) was higher than that of the MIP images (kappa =0.829, P<0.001). cVRT provides a high guiding value in the preoperative diagnosis of brachial plexus schwannomas and is an important basis for formulating surgical plans.

Cinematic rendering improves the AO/OTA classification of distal femur fractures compared to volume rendering: a retrospective single-center study.

Purpose: Correctly classifying distal femur fractures is essential for surgical treatment planning and patient prognosis. This study assesses the potential of Cinematic Rendering (CR) in classifying these fractures, emphasizing its reported ability to produce more realistic images than Volume Rendering (VR). Methods: Data from 88 consecutive patients with distal femoral fractures collected between July 2013 and July 2020 were included. Two orthopedic surgeons independently evaluated the fractures using CR and VR. The inter-rater and intra-rater agreement was evaluated by using the Cicchetti-Allison weighted Kappa method. Accuracy, precision, recall, and F1 score were also calculated. Diagnostic confidence scores (DCSs) for both imaging methods were compared using chi-square or Fisher's exact tests. Results: CR reconstruction yielded excellent inter-observer (Kappa = 0.989) and intra-observer (Kappa = 0.992) agreement, outperforming VR (Kappa = 0.941 and 0.905, respectively). While metrics like accuracy, precision, recall, and F1 scores were higher for CR, the difference was not statistically significant (p > 0.05). However, DCAs significantly favored CR (p < 0.05). Conclusion: CR offers a superior visualization of distal femur fractures than VR. It enhances fracture classification accuracy and bolsters diagnostic confidence. The high inter- and intra-observer agreement underscores its reliability, suggesting its potential clinical importance.

Displasia frontometafisaria 2 asociada con deformidad torácica e hipertensión arterial pulmonar: a propósito de un caso y revisión bibliográfica / Frontometaphyseal dysplasia 2 associated with thoracic deformity, and pulmonary arterial hypertension: a case report and review of literature

La displasia frontometafisaria 2 (DFM2) es una enfermedad rara causada por una mutación en el gen MAP3K7. En este artículo, se informa sobre un paciente de 7 años con DFM2 causada por una variante nueva de corte y empalme en MAP3K7. El paciente presenta las características frecuentes de la DFM2, pero algunas nunca antes informadas. No se dispone de una descripción sistemática de las características de las imágenes tomográficas de la DFM2. Describimos ciertas diferencias en las características de la DFM2, la bibliografía publicada y las manifestaciones imagenológicas generales de la DFM2. Este caso resalta la importancia del valor clínico de la tomografía computada (TC) y la renderización de volúmenes (VR) en el diagnóstico de la DFM2. Las características de la DFM2 pueden observarse claramente en los estudios tomográficos, lo que señala la gran importancia de la TC para el diagnóstico y el tratamiento precoces de los pacientes con DFM2.

Frontometaphyseal dysplasia 2 (FMD2) is a rare disease caused by MAP3K7 gene mutation. We report a 7-year-old sporadic patient with FMD2 due to a de novo splicing variant in MAP3K7. He has the common characteristics of FMD2 but also has some characteristics that have never been reported, which increases the clinical phenotype of FMD2. Moreover, no systematic description of the imaging characteristics of FMD2 in computed tomography (CT) is available. In the present work, we found some different features of FMD2, reviewed previous literature, and summarized the general imaging manifestations of FMD2. This case emphasizes the important clinical value of CT and VR in the diagnosis of FMD2. We can clearly find the characteristics of FMD2 by CT examination, indicating its great significance for the prompt diagnosis and treatment of FMD2 patients.

In Vivo Computed Tomography Direct Volume Rendering of the Anterior Ethmoidal Artery: A Descriptive Anatomical Study

Abstract Introduction The clinical relevance of the anatomy and variations of the anterior ethmoidal artery (AEA) is outstanding, considering its role as a landmark in endoscopic surgery, its importance in the therapy of epistaxis, and the high risks related to iatrogenic injuries. Objective To provide an anatomical description of the course and relationships of the AEA, based on direct computed-tomography (CT)-based 3D volume rendering. Methods Direct volume rendering was performed on 18 subjects who underwent (CT) with contrast medium for suspected cerebral aneurism. Results The topographical location of 36 AEAs was assessed as shown: 10 dehiscent (27.8%), 20 intracanal (55.5%), 6 incomplete canals (16.7%). Distances from important topographic landmarks are reported. Conclusion This work demonstrates that direct 3D volume rendering is a valid imaging technique for a detailed description of the anterior ethmoidal artery thus representing a useful tool for head pre-operatory assessments.

Peeled and piled volume models of the stomach made from a cadaver's sectioned images / Modelos de volumen descortezados y apilados del estómago producidos a partir de imágenes seccionales de un cadáver

Diagnosing and treating stomach diseases requires as many of the related anatomy details as possible. The objective of this study based on the sectioned images of cadaver was to offer interested clinicians anatomical knowledge about the stomach and its neighbors from the new viewpoint. For the raw data, sectioned images of a male cadaver without stomach pathology were used. By manual segmentation and automatic interpolation, a high-quality volume model of the stomach was reconstructed. The model was continuously peeled and piled to synthetically reveal the inside and outside of the stomach. The anterior, posterior, right, and left views of the models were compared with a chosen sectioned image. The numerous stomach images were then put into user-friendly browsing software. Some advantages of this study are that the sectioned images reveal real stomach color with high resolution; the peeled and piled volume models result in new features of the stomach and surroundings; and the processed models can be conveniently browsed in the presented software. These image data and tutorial software are expected to be helpful in acquiring supplementary morphologic information on the stomach and related structures.

El diagnóstico y el tratamiento de enfermedades del estómago requieren del conocimiento del mayor número de detalles posible sobre su anatomía. El objetivo de este estudio, basado en secciones de imágenes de cadáver, es ofrecer a los médicos la anatomía del estómago y sus estructuras vecinas desde un nuevo punto de vista. Se utilizaron imágenes de secciones de un cadáver, de sexo masculino, sin patología del estómago. Por segmentación manual y automática de interpolación, se reconstruyó un modelo de volumen de alta calidad del estómago. El modelo fue descortezado y apilado para revelar sintéticamente el interior y exterior del estómago. Se compararon los puntos de vista anterior, posterior, derecho e izquierdo de los modelos en una sección elegida. Las numerosas imágenes del estómago luego fueron puestas en el software de navegación de fácil uso para el profesional. Algunas de las ventajas de este estudio son que las imágenes seccionadas revelan el color real del estómago con alta resolución; los modelos de volumen descortezados y apilados dan lugar a nuevas funciones del estómago y sus estructuras circundantes; y los modelos procesados pueden ser convenientemente navegados en el software presentado. Se espera que estos datos de imagen y el tutorial del programa sean de utilidad para la adquisición de información morfológica complementaria sobre el estómago y las estructuras relacionadas.

Real-time external labeling layout algorithm for Direct Volume Rendering

Illustrations used in technical and scientific texts often employ labels to correlate the graphic elements and their textual descriptions. Researchers have proposed several algorithms to determine the layout of the annotations on images rendered at interactive frame rates. Generally these layouts can be classified as internal or external. This paper proposes a new algorithm for locating external labels during the real-time direct rendering of volume data. The proposed algorithm uses only the rows of pixels corresponding to the labels anchor points, which optimizes the performance and facilitates its implementation, avoiding the computation of the convex hull for the generated image. Both, the overall visualization performance and the cost of the proposed algorithm are kept in real-time (60 fps) for medium size volumes (about 2563 voxels)(AU).

Las ilustraciones utilizadas en documentos científicos y técnicos utilizan frecuentemente etiquetas para correlacionar los elementos gráficos y sus textos descriptivos. Los investigadores han propuesto diversos algoritmos para determinar el posicionamiento en tiempo real de las correspondientes anotaciones en las imágenes obtenidas en un marco interactivo. Generalmente estos posicionamientos se clasifican como internos o externos. Este artículo propone un nuevo algoritmo para ubicar etiquetas externas en tiempo real durante la obtención de datos de volumen. El algoritmo propuesto usa solo las filas de píxels correspondientes a los puntos de presentación de las etiquetas lo que optimiza el desempeño y facilita la implementación haciendo innecesarios algunos cálculos. Tanto el desempeño general de la vista como el costo del algoritmo propuesto se obtienen en tiempo real (60 fps) para volúmenes de mediana talla (alrededor de 256 voxels)(AU)