Anatomical Details Research Articles

Incidence, epidemiology, radiology, and classification of metastatic spine tumors: WFNS Spine Committee recommendations.

Spinal metastasis (SMs) are the most encountered tumors of the spine. Their occurrence is expected roughly around one to two years after primary tumor diagnosis. Since the advent of Magnetic Resonance Imaging (MRI), this technology has been considered the gold standard for SMs diagnosis and characterization due to its precise ability to comprehend the rate of soft tissue compression/invasion (dural sac/nervous tissue), which is one of the main drivers of management strategies. Computed Tomography (CT) remains unbeatable when a detailed bony anatomy and instability assessment is searched. Nuclear medicine technologies may have a role in diagnosis when standard MR or CT study findings are inconclusive or when the extent of the systemic metastatic disease is studied. The main objective of this study is to offer an update on the epidemiology and radiology of spinal metastasis (SMs), endorsed by the WFNS Spine Committee. A systematic review of the literature of the last ten years gave 1531 results with "spine/spinal metastatic tumors/metastasis AND radiology OR imaging OR classification" as search strings in all fields, of which 56 papers were fully analyzed. The results were discussed and voted on in two consensus meetings of the WFNS (World Federation of Neurosurgical Societies) Spine Committee, reaching a positive or negative consensus using the Delphi method. The committee stated nine recommendations on two main topics: (1) Incidence and epidemiology of SMs; (2) Radiology and classifications of SMs.

Dynamic CT myocardial perfusion combined with coronary CT angiography for detecting hemodynamical significance of coronary artery stenosis: a comparative study.

This study aimed to evaluate the diagnostic performance of combined dynamic stress CT myocardial perfusion imaging (CTP) and coronary CT angiography (CTA) alongside CT-derived fractional flow reserve (CT-FFR) in detecting hemodynamically significant coronary artery disease (CAD). A total of 33 patients (86 vessels) who underwent coronary CTA, dynamic stress CTP, and coronary angiography were included. Vessels exhibiting 30-90% stenosis were subjected to FFR analysis based on coronary angiography (Angio-FFR). Hemodynamic significance, determined by Angio-FFR ≤ 0.80, and imaging findings were evaluated. The evaluation involved a comparison between the combined use of coronary CTA, CTP and CT-FFR, versus the sole use of coronary CTA. Out of 86 coronary vessels, 17 (19.8%) exhibited hemodynamically significant stenosis. The sensitivity, specificity, and accuracy of coronary CTA for detecting ischemia were 94.12%, 34.78%, and 46.51%, respectively. Adding CTP to CTA improved specificity to 88.41%, and accuracy to 87.21%, respectively. The area under the curve (AUC) for the discrimination of functional significant stenosis was 0.798 when using CTA alone, and for CTA plus CTP, it reached 0.910. Furthermore, the combination of CTA, CTP and CT-FFR, showed accuracy of 88.37%, sensitivity of 88.24% and specificity of 88.41% with the AUC of 0.946. The integration of dynamic CTP with CTA significantly enhances the diagnostic accuracy for identifying patients with hemodynamically significant CAD, compared to the use of CTA alone. This study underscores the value of combining CTP, CT-FFR, and CTA in improving diagnostic precision for CAD. The combination of CTP, CT-FFR and CTA offers a multifaceted assessment for patients with CAD by simultaneously providing anatomical detail, functional analysis, and physiological quantification, which facilitating rapid, accurate, and optimal clinical decision-making and significantly enhances patient management.

X-ray fluoroscopy guided localization and steering of miniature robots using virtual reality enhancement

In developing medical interventions using untethered milli- and microrobots, ensuring safety and effectiveness relies on robust methods for real-time robot detection, tracking, and precise localization within the body. The inherent non-transparency of human tissues significantly challenges these efforts, as traditional imaging systems like fluoroscopy often lack crucial anatomical details, potentially compromising intervention safety and efficacy. To address this technological gap, in this study, we build a virtual reality environment housing an exact digital replica (digital twin) of the operational workspace and a robot avatar. We synchronize the virtual and real workspaces and continuously send the robot position data derived from the image stream into the digital twin with short average delay time around 20–25 ms. This allows the operator to steer the robot by tracking its avatar within the digital twin with near real-time temporal resolution. We demonstrate the feasibility of this approach with millirobots steered in confined phantoms. Our concept demonstration herein can pave the way for not only improved procedural safety by complementing fluoroscopic guidance with virtual reality enhancement, but also provides a platform for incorporating various additional real-time derivative data, e.g., instantaneous robot velocity, intraoperative physiological data obtained from the patient, e.g., blood flow rate, and pre-operative physical simulation models, e.g., periodic body motions, to further refine robot control capacity.

A Workflow for Creating Gastric Computational Models from SPARC Scaffolds

In-silico studies are an ideal medium to model and improve our understanding of the mechanisms underlying gastric motility in health and disease. In this study, a workflow to create computational models of the stomach was developed using SPARC scaffolds. Three anatomically based finite element method (FEM) models of the rat stomach incorporating experimental measurements of muscle layer thickness and fiber orientations across the stomach were developed: (i) 2D (surface) FEM model with no thickness, (ii) 3D (volume) FEM model with a fixed thickness across the longitudinal and circular muscle layers, and (iii) 3D (volume) FEM model with varying thickness across the longitudinal and circular muscle layers. The three FEM models were subsequently used in whole-organ slow wave simulations and the impact of anatomical details on the simulation outcomes was investigated. The 3D FEM model with varying thickness was the most computationally expensive, while the 2D FEM model provided the fastest solution (a 200 s simulation took 8 min vs. 38 h to solve). The spatiotemporal profiles of the slow wave activation and propagation in the three FEM models were in good agreement. The largest temporal difference of 1 s in cellular activation was observed between the 2D FEM model and the varying thickness 3D FEM model in the most distal-stomach regions. These FEM models and developed workflow will be used in in-silico studies to improve our understanding of the structure-function relationship in the stomach and identify the optimal parameters of electrical therapies, an alternative treatment for the motility disorders in the stomach. In addition, the developed workflow can be readily used to generate computational models of other organs using SPARC scaffolds.

Resolution-dependent MRI-to-CT translation for orthotopic breast cancer models using deep learning.


This study aims to investigate the feasibility of utilizing generative adversarial networks (GANs) to synthesize high-fidelity CT images from lower-resolution MR images. The goal is to reduce patient exposure to ionizing radiation while maintaining treatment accuracy and accelerating MR image acquisition. The primary focus is to determine the extent to which low-resolution MR images can be utilized to generate high-quality CT images through a systematic study of spatial resolution-dependent MRI-to-CT image conversion. 
Approach. 
Paired MRI-CT images were acquired from healthy control and tumor models, generated by injecting MDA-MB-231 and 4T1 tumor cells into the mammary fat pad of nude and BALB/c mice to ensure model diversification. To explore various MRI resolutions, we downscaled the highest-resolution MR image into three lower resolutions. Using a customized U-Net model, we automated region of interest masking for both MRI and CT modalities with precise alignment, achieved through three-dimensional affine paired MRI-CT registrations. Then our customized models, Nested U-Net Generative Adversarial Network (NUGAN) and Attention U-Net Generative Adversarial Network (AUGAN), were employed to translate low-resolution MR images into high-resolution CT images, followed by evaluation with separate testing datasets.
Main Results.
Our approach successfully generated high-quality CT images (0.142 mm²) from both lower-resolution (0.282 mm²) and higher-resolution (0.142 mm²) MR images, with no statistically significant differences between them, effectively doubling the speed of MR image acquisition. Our customized GANs successfully preserved anatomical details, addressing the typical loss issue seen in other MRI-CT translation techniques across all resolutions of MR image inputs.
 Significance. 
This study demonstrates the potential of using low-resolution MR images to generate high-quality CT images, thereby reducing radiation exposure and expediting MRI acquisition while maintaining accuracy for radiotherapy.&#xD.

Integrating Super-Resolution with Deep Learning for Enhanced Periodontal Bone Loss Segmentation in Panoramic Radiographs

Periodontal disease is a widespread global health concern that necessitates an accurate diagnosis for effective treatment. Traditional diagnostic methods based on panoramic radiographs are often limited by subjective evaluation and low-resolution imaging, leading to suboptimal precision. This study presents an approach that integrates Super-Resolution Generative Adversarial Networks (SRGANs) with deep learning-based segmentation models to enhance the segmentation of periodontal bone loss (PBL) areas on panoramic radiographs. By transforming low-resolution images into high-resolution versions, the proposed method reveals critical anatomical details that are essential for precise diagnostics. The effectiveness of this approach was validated using datasets from the Chungbuk National University Hospital and the Kaggle data portal, demonstrating significant improvements in both image resolution and segmentation accuracy. The SRGAN model, evaluated using the Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index Measure (SSIM) metrics, achieved a PSNR of 30.10 dB and an SSIM of 0.878, indicating high fidelity in image reconstruction. When applied to semantic segmentation using a U-Net architecture, the enhanced images resulted in a dice similarity coefficient (DSC) of 0.91 and an intersection over union (IoU) of 84.9%, compared with 0.72 DSC and 65.4% IoU for native low-resolution images. These results underscore the potential of SRGAN-enhanced imaging to improve PBL area segmentation and suggest broader applications in medical imaging, where enhanced image clarity is crucial for diagnostic accuracy. This study also highlights the importance of further research to expand the dataset diversity and incorporate clinical validation to fully realize the benefits of super-resolution techniques in medical diagnostics.

Exploring the feasibility of FOCUS DWI with deep learning reconstruction for breast cancer diagnosis: A comparative study with conventional DWI.

This study compared field-of-view (FOV) optimized and constrained undistorted single-shot diffusion-weighted imaging (FOCUS DWI) with deep-learning-based reconstruction (DLR) to conventional DWI for breast imaging. This study prospectively enrolled 49 female patients suspected of breast cancer from July to December 2023. The patients underwent conventional and FOCUS breast DWI and data were reconstructed with and without DLR. Two radiologists independently evaluated three images per patient using a 5-point Likert scale. Objective evaluations, including signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC), were conducted using manual region of interest-based analysis. The subjective and objective evaluations were compared using the Friedman test. The scores for the overall image quality, anatomical details, lesion conspicuity, artifacts, and distortion in FOCUS-DLR DWI were higher than in conventional DWI (all P < 0.001). The SNR of FOCUS-DLR DWI was higher than that of conventional and FOCUS DWI (both P < 0.001), while FOCUS and conventional DWI were similar (P = 0.096). Conventional, FOCUS, and FOCUS-DLR DWI had similar CNR and ADC values. Our findings indicate that images produced by FOCUS-DLR DWI were superior to conventional DWI, supporting the applicability of this technique in clinical practice. DLR provides a new approach to optimize breast DWI.

Study on the effect of chlorogenic acid on the antimicrobial effect, physical properties and model accuracy of alginate impression materials.

Dental impressions are essential for accurately capturing the detailed anatomy of teeth and surrounding oral structures. However, these impressions often become contaminated with saliva and blood, making proper disinfection necessary. The application of chemical disinfectants has been associated with negative side effects, leading to suboptimal disinfection practices in clinical settings. The purpose of this study was to evaluate the effectiveness of chlorogenic acid (CA) as a disinfectant for alginate impression materials, the impact of CA disinfection on the physical properties and dimensional accuracy of alginate impressions was also investigated. The physical properties of alginate impression materials, such as elastic recovery, strain-in-compression, initial setting time, and fluidity, were assessed after mixing the alginate impression materials with three different concentrations of CA solution (10 mg/mL, 15 mg/mL, 20 mg/mL). To evaluate the antimicrobial effect of CA, alginate impressions mixed with a 10 mg/mL CA solution and impressions mixed with distilled water (control group) were contaminated with four types of microorganism: Escherichia coli, Staphylococcus aureus, Candida albicans, and Streptococcus pneumoniae. Following a five-minute incubation period, a CA solution at a concentration of either 50mg/mL, 55 mg/mL, or 60 mg/mL was sprayed on the samples for disinfection. Samples were collected at different time intervals (10 min, 20 min, 30min) and cultured to determine the number of colony-forming units (CFU/mL), providing insight into the antimicrobial efficacy of these CA solutions. The dimensional accuracy of alginate impressions was assessed in three groups: one with alginate impressions mixed with distilled water, another with alginate impressions sterilized with available chlorine (2,000 mg/L) mixed with distilled water, and the last group consisting of alginate impressions mixed with 10 mg/mL CA solution and sprayed with 60 mg/mL CA solution. Both the standard model and the plaster model underwent 3D scanning, and the data were processed and compared by software. The root mean square (RMS) was used as a parameter to evaluate the deviation between models. All alginate impression materials mixed with either 10 mg/mL, 15 mg/mL, or 20 mg/mL concentrations of CA solution met the ISO 21563 standard for elastic recovery, strain-in-compression, and fluidity. However, only the material mixed with a concentration of 10 mg/mL CA had an initial setting time within the range specified by the T-6505 Japanese industrial standard. The application of CA solution by mixing or spraying showed significant antimicrobial effects on Staphylococcus aureus, Escherichia coli, Candida albicans, and Streptococcus pneumoniae. There was no significant difference in the dimensional accuracy of the alginate impressions between the group of the CA solution applied, the blank group, or the chlorine intervention group.

CT imaging analysis of the C7 pedicle and lateral mass in children aged 0–14 years

Background and objectiveThere is currently a lack of anatomical research on the C7 pedicle and lateral mass in children aged 0–14 years, and experience with pediatric lower cervical spine surgeries remains limited. This study aims to investigate the anatomical structure of the C7 pedicle and lateral mass in a large pediatric sample to understand their growth patterns, providing imaging and anatomical references for pediatric lower cervical spine surgeries and the design of pediatric C7 screws. MethodsWe measured 12 parameters, including the width, length, height, and angles of the C7 pedicle and lateral mass in children aged 0–14 years. The t-test was used to analyze bilateral and gender differences, and least squares regression was applied for curve fitting analysis. ResultsThe size parameters of the C7 pedicle and lateral mass generally increased with age, while angular parameters fluctuated within specific ranges. The average values for each parameter between ages 0–14 were as follows: D1: 2.78–5.28 mm, D2: 18.15–30.54 mm, D3: 2.44–6.01 mm, angle A: 38.05–44.48°; D4: 6.81–10.94 mm, D5: 5.37–11.23 mm, D6: 8.07–13.28 mm, D7: 1.94–4.88 mm, D8: 5.67–9.39 mm, angle C: 18.50–28.80°, angle D: 43.23–52.01°, angle E: 33.74–44.96°. Bilateral analysis showed no significant differences for most parameters across most age groups, with differences mainly observed in angle A, angle C, D6, and D8. Gender differences were primarily noted in length parameters across different age groups, especially in the 3–4, 6–7, 9–11, and 13–14 age groups. Regression analysis indicated that most parameters followed cubic function curves, while a few followed power or quadratic function curves. ConclusionThis study provides detailed CT imaging anatomy of the C7 pedicle and lateral mass in children aged 0–14 years. Preoperative thin-slice CT scans and careful measurements of key parameters are essential for pediatric lower cervical spine surgeries. The findings offer valuable imaging and anatomical references for pediatric posterior cervical fixation surgery and screw design.

Congenital partial diaphragmatic eventration presenting with Chilaiditi’s sign: a case report

BackgroundChilaiditi’s sign is an incidental radiographic finding, associated with intestinal disposition located between liver and right diaphragm. It is considered as an acquired rather than a congenital condition and the prevalence ranges from 1.18% to 2.4% according to recent adult retrospective studies. The aspects of this rare entity with regards to a 7-month-old male initially misdiagnosed as diaphragmatic hernia is discussed.Case presentationA 4-month-old Caucasian male was misdiagnosed with a congenital diaphragmatic hernia owing to previous hospitalization with complaints of respiratory tract infection. On admission 3 months later, he was free of any signs and symptoms of intestinal obstruction or respiratory distress. Thorax computed tomography revealed Chilaiditi’s sign. A diagnostic laparoscopy was regarded necessary to evaluate the anatomical details. The most prominent finding was the lack of muscle fibers and almost transparent appearance of the medial aspect of the partially eventrated right hemidiaphragm. Owing to delicate anatomical presentation, diaphragmatic plication was considered hazardous. The patient is doing well and under follow-up.ConclusionsIt is obvious that Chilaiditi’s sign is not always a completely incidental finding of no consequence, and may indicate an underlying congenital diaphragmatic pathology, clearly defined by laparoscopic evaluation in this case.

The Key Role of 3D TEE in Assessing the Morphology of Degenerative Mitral Valve Regurgitation

Two-dimensional transthoracic echocardiography (2D TTE) and two-dimensional transesophageal echocardiography (2D TEE) are regarded as the main imaging techniques for the assessment of degenerative mitral valve regurgitation (DMVR). However, describing the complex morphology of DMVR with 2D TTE and 2D TEE remains at the very least challenging. Three-dimensional (3D) TEE is an ideal technique for illustrating the extremely variable morphology of DMVR, providing images of unparalleled quality in terms of anatomical detail. In this review, we describe the key role of 3D TEE in various morphological scenarios that reflect everyday experiences in an echocardiographic laboratory. We also discuss the growing role of 3D TEE in mitral valve (MV) transcatheter edge-to-edge repair (TEER) and new modalities such as photorealistic and transparent displays, surface rendering parametric color maps, new algorithms for MVR quantification, and the potential role of new mini-TEE probes in adult patients with DMVR.

Gross Anatomy of the Equine Masseter Muscle: Lamination and Intramuscular Course of the N. Massetericus.

The masticatory muscles of the horse are arranged in an asymmetrical pattern. Four individual muscles on the medial side of the mandible are opposed by one muscle (M. masseter) on the lateral side. However, recent studies on various herbivorous mammals indicate that the masseter muscle features a complex stratigraphic structure that might account for a functional diversity resembling an arrangement of several individual muscles. The functional consideration of the multidirectional equine masticatory movements leads to a similar hypothesis. In order to elucidate the detailed anatomy of the equine masseter muscle, eight cadaveric equine heads were dissected. Additional 29 skull specimens were assessed with regard to the masseteric attachment within the Fossa masseterica. A constant arrangement of nine individual muscular layers within the masseteric muscle was determined. The individual layers were clearly separated by tendon plates and their attachment areas at the masseteric fossa of the mandible were arranged in a constant pattern of bony ridges. With similar consistency, the main trunk of the masseteric nerve was found to run from dorsocaudal to ventrorostral: On that course, the nerve penetrated between the muscular layers from medial to lateral at constant positions. The findings of this study serve as a basis for further studies with the aim of developing biomechanical concepts of equine masticatory movement.

A 3D-Printed, High-Fidelity Pelvis Training Model: Cookbook Instructions and First Experience.

Background: Since laparoscopic surgery became the gold standard for colorectal procedures, specific skills are required to achieve good outcomes. The best way to acquire basic and advanced skills and reach the learning curve plateau is by using dedicated simulators: box-trainers, video-trainers and virtual reality simulators. Laparoscopic skills training outside the operating room is cost-beneficial, faster and safer, and does not harm the patient. When compared to box-trainers, virtual reality simulators and cadaver models have no additional benefits. Several laparoscopic trainers available on the market as well as homemade box and video-trainers, most of them using plastic boxes and standard webcams, were described in the literature. The majority of them involve training on a flat surface without any anatomical environment. In addition to their demonstrated benefits, box-trainers which add anatomic details can improve the training quality and skills development of surgeons. Methods: We created a 3D-printed anatomic pelvi-trainer which offers a real-size narrow pelvic space environment for training. The model was created starting with a CT-scan performed on a female pelvis from the Anatomy Museum (Cluj-Napoca University of Medicine and Pharmacy, Romania), using Invesalius 3 software (Centro de Tecnologia da informação Renato Archer CTI, InVesalius open-source software, Campinas, Brazil) for segmentation, Fusion 360 with Netfabb software (Autodesk software company, Fusion 360 with Netfabb, San Francisco, CA, USA) for 3D modeling and a FDM technology 3D printer (Stratasys 3D printing company, Fortus 380mc 3D printer, Minneapolis, MN, USA). In addition, a metal mold for casting silicone valves was made for camera and endoscopic instruments ports. The trainer was tested and compared using a laparoscopic camera, a standard full HD webcam and "V-Box" (INTECH-Innovative Training Technologies, Milano, Italia), a dedicated hard paper box. The pelvi-trainer was tested by 33 surgeons with different qualifications and expertise. Results: We made a complete box-trainer with a versatile 3D-printed pelvi-trainer inside, designed for a wide range of basic and advanced laparoscopic skills training in the narrow pelvic space. We assessed the feedback of 33 surgeons regarding their experience using the anatomic 3D-printed pelvi-trainer for laparoscopic surgery training in the narrow pelvic space. Each surgeon tested the pelvi-trainer in three different setups: using a laparoscopic camera, using a webcam connected to a laptop and a "V-BOX" hard paper box. In the experiments that were performed, each participant completed a questionnaire regarding his/her experience using the pelvi-trainer. The results were positive, validating the device as a valid tool for training. Conclusions: We validated the anatomic pelvi-trainer designed by our team as a valuable alternative for basic and advanced laparoscopic surgery training outside the operating room for pelvic organs procedures, proving that it supports a much faster learning curve for colorectal procedures without harming the patients.

A Multi-Hierarchical Complementary Feature Interaction Network for Accelerated Multi-Modal MR Imaging

Magnetic resonance (MR) imaging is widely used in the clinical field due to its non-invasiveness, but the long scanning time is still a bottleneck for its popularization. Using the complementary information between multi-modal imaging to accelerate imaging provides a novel and effective MR fast imaging solution. However, previous technologies mostly use simple fusion methods and fail to fully utilize their potential sharable knowledge. In this study, we introduced a novel multi-hierarchical complementary feature interaction network (MHCFIN) to realize joint reconstruction of multi-modal MR images with undersampled data and thus accelerate multi-modal imaging. Firstly, multiple attention mechanisms are integrated with a dual-branch encoder–decoder network to represent shared features and complementary features of different modalities. In the decoding stage, the multi-modal feature interaction module (MMFIM) acts as a bridge between the two branches, realizing complementary knowledge transfer between different modalities through cross-level fusion. The single-modal feature fusion module (SMFFM) carries out multi-scale feature representation and optimization of the single modality, preserving better anatomical details. Extensive experiments are conducted under different sampling patterns and acceleration factors. The results show that this proposed method achieves obvious improvement compared with existing state-of-the-art reconstruction methods in both visual quality and quantity.

New Insights on the Turin Shroud’s Body Image: Face Image at Different Wavelengths and its Double Superficiality

Various images of the face of the Turin Shroud Man, acquired at different wavelengths, from the near infrared region to the ultraviolet, have been studied and compared. A correlation as a function of the wavelength, between the penetration depth in the fabric of the incident light and the anatomic details visible on the images, is discussed based on the physical properties of linen threads and light. In addition, the backside of the Turin Shroud, in correspondence of the region of the face, has been examined, evidencing the possible presence of a second superficial image impressed on the backside. Notwithstanding the high level of scientific knowledge today reached, there is no known physical/chemical process which allows to explain all the properties of the Turin Shroud’s body image. According to our scientific knowledge, the corpse of a dead man cannot produce an energy capable to imprint on a linen cloth an image with all the microscopical and macroscopical properties discovered by analyzing the body image of the Turin Shroud, which has not yet been reproduced in any laboratory in the world. According to faith the corpse of a living Man can do it, during the resurrection, assuming a different state of matter. With this respect, the Turin Shroud can be considered as a two-thousand-old relic witnessing to the humanity, just in the age of science, the reasonableness of the faith in the resurrection.

Arrangements of intramembranous muscles of wings are influenced by body mass across the radiation of phyllostomid bats.

Extensive research into bat flight mechanisms has highlighted the complex functional and evolutionary dynamics of their wing structures, yet the anatomical details of certain wing muscles remain elusive. In particular, the intramembranous plagiopatagiales proprii muscles, located within the plagiopatagium-an area of the wing lacking direct joint connections-exhibit remarkable variation across bat families. These muscles, which extend anteroposteriorly in macroscopic bundles, play a crucial role in wing stiffening, modulating membrane tension, and reducing wing curvature during flight. Since larger bats tend to have higher wing loading (WL; the ratio of body mass [BMa] to wing area) and may therefore experience increased patagial curvature and resultant drag, we hypothesized that body size significantly influences the evolutionary development of the plagiopatagiales proprii muscles. This study investigates the relationship between BMa and the morphology of the plagiopatagiales proprii in New World leaf-nosed bats (Phyllostomidae), employing bivariate allometry, multivariate analysis, and comparative phylogenetic methods across 24 species from eight phyllostomid subfamilies. Our findings reveal a significant phylogenetic signal in muscle architecture, along with positive evolutionary allometry in muscle area. This suggests an adaptive increase in muscle size in larger species, likely to counterbalance the increased WL, reduce wing curvature, and minimize drag. This research enhances our understanding of the functional and adaptive morphological evolution of intramembranous wing muscles in phyllostomid bats, underscoring their evolutionary significance.

Medical Image Fusion for Multiple Diseases Features Enhancement

ABSTRACTThroughout the past 20 years, medical imaging has found extensive application in clinical diagnosis. Doctors may find it difficult to diagnose diseases using only one imaging modality. The main objective of multimodal medical image fusion (MMIF) is to improve both the accuracy and quality of clinical assessments by extracting structural and spectral information from source images. This study proposes a novel MMIF method to assist doctors and postoperations such as image segmentation, classification, and further surgical procedures. Initially, the intensity‐hue‐saturation (IHS) model is utilized to decompose the positron emission tomography (PET)/single photon emission computed tomography (SPECT) image, followed by a hue‐angle mapping method to discriminate high‐ and low‐activity regions in the PET images. Then, a proposed structure feature adjustment (SFA) mechanism is used as a fusion strategy for high‐ and low‐activity regions to obtain structural and anatomical details with minimum color distortion. In the second step, a new multi‐discriminator generative adversarial network (MDcGAN) approach is proposed for obtaining the final fused image. The qualitative and quantitative results demonstrate that the proposed method is superior to existing MMIF methods in preserving the structural, anatomical, and functional details of the PET/SPECT images. Through our assessment, involving visual analysis and subsequent verification using statistical metrics, it becomes evident that color changes contribute substantial visual information to the fusion of PET and MR images. The quantitative outcomes demonstrate that, in the majority of cases, the proposed algorithm consistently outperformed other methods. Yet, in a few instances, it achieved the second‐highest results. The validity of the proposed method was confirmed using diverse modalities, encompassing a total of 1012 image pairs.

A Macrocyclic Hybrid PET/MRI Probe for Quantitative Perfusion Imaging In Vivo.

Perfusion dynamics play a vital role in delivering essential nutrients and oxygen to tissues while removing metabolic waste products. Imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET) use contrast agents to visualize perfusion and clearance patterns; however, each technique has specific limitations. Hybrid PET/MRI combines the quantitative power and sensitivity of PET with the high functional and anatomical detail of MRI and holds great promise for precision in molecular imaging. However, the development of dual PET/MRI probes has been hampered by challenging synthesis and radiolabeling. Here, we present a novel PET/MRI probe, [18F][Gd(FL1)], which exhibits excellent stability comparable to macrocyclic MRI contrast agents used in clinical practice. The unique molecular design of [18F][Gd(FL1)] allows selective and expeditious radiolabeling of the gadolinium chelate in the final synthetic step. Leveraging the strengths of MRI and PET signals, the probe enables quantitative in vivo mapping of perfusion and excretion dynamics through an innovative voxel-based analysis. The diagnostic capabilities of [18F][Gd(FL1)] were demonstrated in a pilot study on healthy mice, successfully detecting early cases of unilateral renal dysfunction, a condition that is typically challenging to diagnose. This study introduces a new approach for PET/MRI and emphasizes a streamlined probe design for practical synthesis and improved diagnostic accuracy.

Translucent zirconia dental prosthesis processed by Direct Ink Writing: Updates and challenges

Direct ink writing (DIW) is an extrusion-based additive manufacturing technique, which uses a layer-by-layer deposition of an ink, usually containing high solid loads and low concentration of additives, to provide plasticity and structural stability for the construction of near-net-shaped pieces. In this work, a zirconia stabilized with 5 mol% Y2O3 colloidal ink was developed aiming to obtain dense prototypes, partially translucent, with potential for making dental prostheses. Cylindrical pieces (Ø 20 mm × 2.5 mm), prismatic bars (55 × 5 × 4 mm) and 3-element dental prostheses were printed based on Computer-aided design (CAD) models, using a printing speed of 10 mm.s−1 and a nozzle with Ø 0.25 mm. The printed samples were dried at strictly controlled conditions, debinded using an optimized thermal cycle, and sintered at 1600 °C-2 h. The sintered parts were characterized by X-ray diffraction, scanning electron microscopy, Vickers hardness, fracture toughness and bending strength. Concerning dental prosthesis, a post-processing finishing strategy was performed on pre-sintered bodies to highlight the anatomical details. After sintering, samples presented relative density around 94–95 %, Vickers hardness, fracture toughness and Young Modulus of 12.7 ± 0.3GPa, 5.31 ± 0.21 MPa.m1/2 and 195.4 ± 45 GPa, respectively. A characteristic strength (σ0) of 303 MPa was attained, which is above the requirements for its application as ceramic single-unit dental prostheses. A critical analysis of the technological difficulties of this 3D printing technique for manufacturing dental prostheses is presented, while future directions are addressed.

The concept of the Schwann cell by Louis Ranvier and his school: The ‘interannular segment’ as a cell unit

ABSTRACT The hundredth anniversary of the death of French histologist Louis Ranvier (1835‒1922) is an opportunity to reexamine his elaboration of the first concept of the Schwann cell. A loyal supporter of Theodor Schwann and his discoveries, and an attentive reader of the work of Albert von Kölliker, Ranvier studied the anatomic details of the myelinated nerve fiber with picrocarminate staining. The diffusion of the dye into the nerve fiber at the cut ends and at the sites of the annular constrictions (Ranvier’s nodes) set him on the path to defining a new cellular entity surrounding the axon, the “interannular segment,” comprising a Schwann nucleus, myelin, and cytoplasm. Ramón y Cajal recognized in 1913 that this concept of the Schwann cell according to Ranvier and his pupil William Vignal had been a brilliant intuition, but it was widely rejected until it was rediscovered using electron microscopy in the 1950s. The article reconstructs the steps of Ranvier and Vignal in building this Schwann cell concept, as well as establishing bridges with the discoveries of the 1950s.