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1.
ACS Nano ; 18(33): 22080-22094, 2024 Aug 20.
Article de Anglais | MEDLINE | ID: mdl-39102350

RÉSUMÉ

Meningeal vascular network is significant in neurology and neurosurgery. However, high-resolution imaging of intact meningeal vascular network is lacking. In this work, we develop a practical experimental method to ensure that the intact meninges are morphologically unfolded and fixed in an agarose gel. With the help of high-brightness polymer dots (Pdots) as probe, macroscopic and detailed imaging of the vascular network on the intact dorsal meninges can be performed. Meningeal vessels are symmetrically distributed along the superior sagittal sinus, and the distribution of meningeal vessels had a certain degree of hierarchy. The meninges are thicker blood vessels and capillary networks from the outside to the inside. Moreover, the diameter of the capillaries is 3.96 ± 0.89 µm. Interestingly, meningeal primo vessels in the central nervous system of mice is imaged with the diameter of 4.18 ± 1.18 µm, which has not been reported previously. It is worth mentioning that we found that orthotopic xenografts of brain tumors caused the appearance of corneal neovascularization and morphological changes in optic nerve microvessels. In conclusion, our work provides an effective Pdots-based imaging method for follow-up research on meningeal vascular-related diseases, and illustrates that the eye can serve as a window for the prevention and diagnosis of brain diseases.


Sujet(s)
Encéphale , Méninges , Animaux , Souris , Méninges/imagerie diagnostique , Méninges/vascularisation , Encéphale/vascularisation , Encéphale/imagerie diagnostique , Colorants fluorescents/composition chimique , Humains , Oeil/vascularisation , Oeil/imagerie diagnostique , Polymères/composition chimique , Tumeurs du cerveau/imagerie diagnostique , Tumeurs du cerveau/anatomopathologie , Imagerie optique , Boîtes quantiques/composition chimique
2.
Neuroradiology ; 66(9): 1481-1493, 2024 Sep.
Article de Anglais | MEDLINE | ID: mdl-38995394

RÉSUMÉ

BACKGROUND: Visualizing (micro)vascular structures remains challenging for researchers and clinicians due to limitations in traditional radiological imaging methods. Exploring the role of vascular development in craniofacial malformations in experimental settings can enhance understanding of these processes, with the effectiveness of high-resolution imaging techniques being crucial for successful research in this field. Micro-CT imaging offers 3D microstructural insights, but requires contrast-enhancing staining agents (CESAs) for visualizing (micro)-vascular tissues, known as contrast-enhanced micro-CT (CECT). As effective contrast agents are crucial for optimal visualization, this review focuses on comparative studies investigating such agents for micro-vascular tissue imaging using micro-CT. Furthermore, we demonstrate the utilization of B-Lugol solution as a promising contrast agent for acquiring high-quality micro-CT images of (micro)vascular structures in human embryonic samples. METHOD: This scoping review followed Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols. PubMed database provided relevant articles, screened initially by title and abstract. Inclusion and exclusion criteria defined outcomes of interest. RESULTS: From an initial search, 273 records were identified, narrowed down to 9 articles after applying our criteria. Additionally, two articles were added through citation searching. This, a total of 11 articles were incorporated in this study. CONCLUSION: This micro-CT contrast agent review underscores the need for tailored choices based on research goals. Both Barium sulfate and Iodine-based agents showing excellent results, providing high resolution (micro) vascular content, especially in ex-vivo specimens. However, careful consideration of protocols and tissue characteristics remains imperative for optimizing the effectiveness of micro-CT imaging for the study of cranio-facial vascular development.


Sujet(s)
Produits de contraste , Microtomographie aux rayons X , Humains , Microtomographie aux rayons X/méthodes , Imagerie tridimensionnelle/méthodes
3.
Sensors (Basel) ; 24(14)2024 Jul 19.
Article de Anglais | MEDLINE | ID: mdl-39066086

RÉSUMÉ

Single-pixel imaging (SPI) is an alternative method for obtaining images using a single photodetector, which has numerous advantages over the traditional matrix-based approach. However, most experimental SPI realizations provide relatively low resolution compared to matrix-based imaging systems. Here, we show a simple yet effective experimental method to scale up the resolution of SPI. Our imaging system utilizes patterns based on Hadamard matrices, which, when reshaped to a variable aspect ratio, allow us to improve resolution along one of the axes, while sweeping of patterns improves resolution along the second axis. This work paves the way towards novel imaging systems that retain the advantages of SPI and obtain resolution comparable to matrix-based systems.

4.
Diagnostics (Basel) ; 14(13)2024 Jun 25.
Article de Anglais | MEDLINE | ID: mdl-39001242

RÉSUMÉ

BACKGROUND: Macular telangiectasia (MacTel), also known as idiopathic juxtafoveolar telangiectasis (IJFTs), involves telangiectatic changes in the macular capillary network. The most common variant, MacTel type 2, has distinct clinical features and management strategies. METHODS: This study offers a comprehensive review of MacTel and focuses on a series of three patients diagnosed with MacTel type 2 in our clinic. A meticulous ophthalmological evaluation, augmented by high-resolution imaging techniques like optical coherence tomography (OCT), OCT angiography (OCT-A), fundus autofluorescence (FAF), fluorescein angiography (FA), and adaptive optics (AOs) imaging, was conducted. RESULTS: The findings revealed normal anterior segment features and a grayish discoloration in the temporal perifoveal area on fundus examination. OCT exhibited hyporeflective cavities in the inner and outer neurosensory retina, along with other changes, while OCT-A identified retinal telangiectatic vessels in the deep capillary plexus. FAF demonstrated increased foveal autofluorescence, while FA initially detected telangiectatic capillaries followed by diffuse perilesional leakage in the later phase. Adaptive optics images showed the cone mosaic pattern. Notably, one patient developed a macular hole as a complication, which was successfully managed surgically. CONCLUSION: This study underscores the challenges in diagnosing and managing MacTel, emphasizing the importance of a multidisciplinary approach and regular follow-ups for optimal outcomes.

5.
J Synchrotron Radiat ; 31(Pt 4): 923-935, 2024 Jul 01.
Article de Anglais | MEDLINE | ID: mdl-38861370

RÉSUMÉ

X-rays can penetrate deeply into biological cells and thus allow for examination of their internal structures with high spatial resolution. In this study, X-ray phase-contrast imaging and tomography is combined with an X-ray-compatible optical stretcher and microfluidic sample delivery. Using this setup, individual cells can be kept in suspension while they are examined with the X-ray beam at a synchrotron. From the recorded holograms, 2D phase shift images that are proportional to the projected local electron density of the investigated cell can be calculated. From the tomographic reconstruction of multiple such projections the 3D electron density can be obtained. The cells can thus be studied in a hydrated or even living state, thus avoiding artifacts from freezing, drying or embedding, and can in principle also be subjected to different sample environments or mechanical strains. This combination of techniques is applied to living as well as fixed and stained NIH3T3 mouse fibroblasts and the effect of the beam energy on the phase shifts is investigated. Furthermore, a 3D algebraic reconstruction scheme and a dedicated mathematical description is used to follow the motion of the trapped cells in the optical stretcher for multiple rotations.

6.
Annu Rev Anal Chem (Palo Alto Calif) ; 17(1): 103-126, 2024 Jul.
Article de Anglais | MEDLINE | ID: mdl-38603469

RÉSUMÉ

The electrochemical interface formed between an electrode and an electrolyte significantly affects the rate and mechanism of the electrode reaction through its structure and properties, which vary across the interface. The scope of the interface has been expanded, along with the development of energy electrochemistry, where a solid-electrolyte interphase may form on the electrode and the active materials change properties near the surface region. Developing a comprehensive understanding of electrochemical interfaces and interphases necessitates three-dimensional spatial resolution characterization. Atomic force microscopy (AFM) offers advantages of imaging and long-range force measurements. Here we assess the capabilities of AFM by comparing the force curves of different regimes and various imaging modes for in situ characterizing of electrochemical interfaces and interphases. Selected examples of progress on work related to the structures and processes of electrode surfaces, electrical double layers, and lithium battery systems are subsequently illustrated. Finally, this review provides perspectives on the future development of electrochemical AFM.

7.
Water Res ; 255: 121548, 2024 May 15.
Article de Anglais | MEDLINE | ID: mdl-38569357

RÉSUMÉ

Rhizoremediation of wetland plants is an environmentally friendly strategy for sediment phosphorous (P) removal, the basic underlying principle of which is the complex interactions between roots and microorganisms. This study investigated the immobilization and mobilization mechanisms of P in the rhizosphere of wetland plants using high-resolution spatial visualization techniques and metagenomic sequencing. Two-dimensional visualization of the spatial distribution of P, iron (Fe) and manganese (Mn) indicated that the sequestration of Fe-oxides rather than Mn-oxides caused the depletion of labile P, resulting in an increase in the Fe-adsorbed P fraction. Plants altered the rhizospheric environments and P-cycling microbial community to mobilize low-availability P from sediments. Mineral P solubilization and organic P mineralization were enhanced by local acidification and increased phosphatase activity, respectively. Microbial P mobilization also increased with increasing relative abundances of P solubilization and mineralization genes (gcd and phnW) and decreasing P transportation genes (ugpA, ugpB, and pit) genes in the rhizosphere. These processes led to the remobilization of 10.04 % of inorganic P, and 15.23 % of organic P, in the rhizosphere during the incubation period. However, the resupply of P via the above processes did not compensate for the depletion of rhizospheric P via root uptake and mineral sequestration. Our results provide novel insights into the mechanisms of rhizospheric P cycling, which will help to inform future phytoremediation strategies.

8.
Skeletal Radiol ; 53(9): 1889-1902, 2024 Sep.
Article de Anglais | MEDLINE | ID: mdl-38441616

RÉSUMÉ

In musculoskeletal imaging, CT is used in a wide range of indications, either alone or in a synergistic approach with MRI. While MRI is the preferred modality for the assessment of soft tissues and bone marrow, CT excels in the imaging of high-contrast structures, such as mineralized tissue. Additionally, the introduction of dual-energy CT in clinical practice two decades ago opened the door for spectral imaging applications. Recently, the advent of photon-counting detectors (PCDs) has further advanced the potential of CT, at least in theory. Compared to conventional energy-integrating detectors (EIDs), PCDs provide superior spatial resolution, reduced noise, and intrinsic spectral imaging capabilities. This review briefly describes the technical advantages of PCDs. For each technical feature, the corresponding applications in musculoskeletal imaging will be discussed, including high-spatial resolution imaging for the assessment of bone and crystal deposits, low-dose applications such as whole-body CT, as well as spectral imaging applications including the characterization of crystal deposits and imaging of metal hardware. Finally, we will highlight the potential of PCD-CT in emerging applications, underscoring the need for further preclinical and clinical validation to unleash its full clinical potential.


Sujet(s)
Maladies ostéomusculaires , Photons , Tomodensitométrie , Humains , Tomodensitométrie/méthodes , Maladies ostéomusculaires/imagerie diagnostique , Appareil locomoteur/imagerie diagnostique
9.
Heliyon ; 10(4): e26172, 2024 Feb 29.
Article de Anglais | MEDLINE | ID: mdl-38390116

RÉSUMÉ

This research presents a groundbreaking approach in virus-related research, addressing challenges in electron microscopy (EM). This imaging technique has been crucial in exploring virus structures; however, traditional methods involve complex sample preparations and the risk of contamination. Herein, we introduce an approach that overcomes these obstacles, enabling high-resolution virus imaging without toxic staining procedures. Focusing on Begomovirus particles, an economically significant plant virus genus, our images confirm their non-enveloped structure and their twin icosahedral symmetry. Our methods involve sample collection, purification, and crystallization, followed by transmission electron microscopy - selected area electron diffraction (TEM-SAED) analysis. Notably, this study achieves 2D and 3D virus imaging through standard TEM, providing a new avenue for virus structure analysis and advancing virus-related research. Remarkable high image quality stemmed from the crystallization process, offering exciting possibilities for improving virus research and diagnosis while eliminating staining limitations.

10.
Clin Case Rep ; 12(1): e8376, 2024 Jan.
Article de Anglais | MEDLINE | ID: mdl-38161648

RÉSUMÉ

This study paper's main goal is to report rare cases of skull base meningiomas that exemplify the complexities of diagnosis, therapy, and postoperative care. By describing these rare cases, we hope to advance knowledge of the clinical signs, difficulties, and prognoses of skull base meningiomas in a challenging anatomical setting. In the posterior cranial fossa, our investigation reveals a unique example of skull base meningioma that involved numerous cranial nerves and complex vasculature. A variety of visual abnormalities were present in the patient's clinical presentations, highlighting the wide range of symptoms that these tumors might cause depending on their precise positions. These cases highlight the critical importance of preoperative imaging, including high-resolution MRI and angiography, as well as the diagnostic difficulties these tumors pertain. By reporting these instances, our research adds to the body of knowledge about skull base meningiomas and offers insightful information about the nuances of their therapies. Our findings highlight the importance of individualized treatment plans, interdisciplinary cooperation, and the demand for continued study to better comprehend these convoluted tumors. Such studies are essential for advancing our knowledge of these enigmatic tumors, guiding clinical judgment, and eventually improving patient outcomes. These findings are important because they can fill information gaps, improve treatment plans, and encourage additional research in neuro-oncology. Abstract: This study presents a series of three rare cases of skull base meningiomas, emphasizing the complexities in diagnosis, treatment, and postoperative care. The patients' clinical presentations and imaging highlighted the diverse symptoms and challenges associated with these tumors, found in intricate anatomical locations. The cases underscore the crucial role of preoperative high-resolution imaging and angiography in diagnostic accuracy. Surgical intervention, guided by a multidisciplinary approach, is pivotal in managing these demanding cases. Histopathological examinations confirmed atypical meningiomas. The postoperative phases involved meticulous care to ensure optimal recovery and functional outcomes. Our findings contribute to the understanding of skull base meningiomas, emphasizing the need for personalized treatment plans and ongoing research to improve patient outcomes in neuro-oncology.

11.
Phys Med Biol ; 69(4)2024 Feb 05.
Article de Anglais | MEDLINE | ID: mdl-38241726

RÉSUMÉ

Objective. High-resolution magnetic resonance imaging (MRI) can enhance lesion diagnosis, prognosis, and delineation. However, gradient power and hardware limitations prohibit recording thin slices or sub-1 mm resolution. Furthermore, long scan time is not clinically acceptable. Conventional high-resolution images generated using statistical or analytical methods include the limitation of capturing complex, high-dimensional image data with intricate patterns and structures. This study aims to harness cutting-edge diffusion probabilistic deep learning techniques to create a framework for generating high-resolution MRI from low-resolution counterparts, improving the uncertainty of denoising diffusion probabilistic models (DDPM).Approach. DDPM includes two processes. The forward process employs a Markov chain to systematically introduce Gaussian noise to low-resolution MRI images. In the reverse process, a U-Net model is trained to denoise the forward process images and produce high-resolution images conditioned on the features of their low-resolution counterparts. The proposed framework was demonstrated using T2-weighted MRI images from institutional prostate patients and brain patients collected in the Brain Tumor Segmentation Challenge 2020 (BraTS2020).Main results. For the prostate dataset, the bicubic interpolation model (Bicubic), conditional generative-adversarial network (CGAN), and our proposed DDPM framework improved the noise quality measure from low-resolution images by 4.4%, 5.7%, and 12.8%, respectively. Our method enhanced the signal-to-noise ratios by 11.7%, surpassing Bicubic (9.8%) and CGAN (8.1%). In the BraTS2020 dataset, the proposed framework and Bicubic enhanced peak signal-to-noise ratio from resolution-degraded images by 9.1% and 5.8%. The multi-scale structural similarity indexes were 0.970 ± 0.019, 0.968 ± 0.022, and 0.967 ± 0.023 for the proposed method, CGAN, and Bicubic, respectively.Significance. This study explores a deep learning-based diffusion probabilistic framework for improving MR image resolution. Such a framework can be used to improve clinical workflow by obtaining high-resolution images without penalty of the long scan time. Future investigation will likely focus on prospectively testing the efficacy of this framework with different clinical indications.


Sujet(s)
Bisacodyl/analogues et dérivés , Imagerie par résonance magnétique , Modèles statistiques , Mâle , Humains , Rapport signal-bruit , Encéphale/imagerie diagnostique , Traitement d'image par ordinateur/méthodes
12.
Laryngoscope ; 134(2): 684-687, 2024 Feb.
Article de Anglais | MEDLINE | ID: mdl-37462362

RÉSUMÉ

OBJECTIVE: The vascular anatomy of the proximal subscapular artery has been previously classified into 2 major types depending on the presence of a common subscapular trunk. The purpose of this study was to determine the utility, reliability, and cost of routine chest imaging to identify these anatomical variations. METHODS: Data were collected retrospectively at a tertiary medical center for patients who were undergoing CT chest for various indications between October 2019 and October 2020. Two independent and blinded readers interpreted CT chest with contrast of 52 patients for a total 104 sides. RESULTS: The proximal branching pattern of the subscapular system was identified to have a common trunk in 99 (95%) sides. The remaining five sides (5%) demonstrated two arterial pedicles; with one patient exhibiting the variant anatomy bilaterally. CONCLUSION: Preoperative CT chest with contrast can accurately identify anatomic variation of the subscapular vascular system. For complex reconstruction requiring a single anastomosis in the vessel depleted neck, preoperative imaging can assure selection of a type I vascular anatomy of the proximal subscapular system. Preoperative imaging with contrasted CT has value in assessing this anatomy when planning for chimeric flaps involving circumflex scapular and thoracodorsal arteries. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:684-687, 2024.


Sujet(s)
Cardiopathies congénitales , Scapula , Lambeaux chirurgicaux , Humains , Études rétrospectives , Reproductibilité des résultats , Lambeaux chirurgicaux/vascularisation , Scapula/imagerie diagnostique , Tomodensitométrie
13.
J Biophotonics ; 17(1): e202300275, 2024 01.
Article de Anglais | MEDLINE | ID: mdl-37703431

RÉSUMÉ

Histopathology for tumor margin assessment is time-consuming and expensive. High-resolution full-field optical coherence tomography (FF-OCT) images fresh tissues rapidly at cellular resolution and potentially facilitates evaluation. Here, we define FF-OCT features of normal and neoplastic skin lesions in fresh ex vivo tissues and assess its diagnostic accuracy for malignancies. For this, normal and neoplastic tissues were obtained from Mohs surgery, imaged using FF-OCT, and their features were described. Two expert OCT readers conducted a blinded analysis to evaluate their diagnostic accuracies, using histopathology as the ground truth. A convolutional neural network was built to distinguish and outline normal structures and tumors. Of the 113 tissues imaged, 95 (84%) had a tumor (75 basal cell carcinomas [BCCs] and 17 squamous cell carcinomas [SCCs]). The average reader diagnostic accuracy was 88.1%, with a sensitivity of 93.7%, and a specificity of 58.3%. The artificial intelligence (AI) model achieved a diagnostic accuracy of 87.6 ± 5.9%, sensitivity of 93.2 ± 2.1%, and specificity of 81.2 ± 9.2%. A mean intersection-over-union of 60.3 ± 10.1% was achieved when delineating the nodular BCC from normal structures. Limitation of the study was the small sample size for all tumors, especially SCCs. However, based on our preliminary results, we envision FF-OCT to rapidly image fresh tissues, facilitating surgical margin assessment. AI algorithms can aid in automated tumor detection, enabling widespread adoption of this technique.


Sujet(s)
Carcinome basocellulaire , Carcinome épidermoïde , Tumeurs cutanées , Humains , Tumeurs cutanées/imagerie diagnostique , Tumeurs cutanées/chirurgie , Chirurgie de Mohs/méthodes , Intelligence artificielle , Études de faisabilité , Tomographie par cohérence optique/méthodes , Carcinome basocellulaire/imagerie diagnostique , Carcinome basocellulaire/chirurgie , Carcinome basocellulaire/anatomopathologie , Carcinome épidermoïde/imagerie diagnostique , Carcinome épidermoïde/chirurgie
14.
Geobiology ; 22(1): e12579, 2024.
Article de Anglais | MEDLINE | ID: mdl-37984450

RÉSUMÉ

Frutexites-like microstructures are described from the exhumed Late Devonian reef complexes of the northern Canning Basin, Western Australia. Several high-resolution imaging techniques, including X-ray microcomputerised tomography, scanning electron microscopy and X-ray fluorescence microscopy, were used to investigate morphology and composition in two samples. Three types of Frutexites-like microstructures (Types I-III) have been identified. Type I, found lining an early marine cement-filled cavity in fore-reef grainstone facies, consists of dendritic structures formed primarily of coccoid bacteria with filamentous bacteria embedded in sheets of amorphous extracellular polymeric substances (EPS). These ferromanganiferous dendrites have laminated to spheroidal textures. Types II and III are from a toe-of-slope hardground. Type II grew in a crypt between two corals, is also dendritic and composed of bacilliform and filamentous bacteria embedded in an amorphous EPS sheet. The opaqueness of these ferriferous dendrites precludes more detailed description of textures. Type III grew as branching columnar microstromatolites and is composed of entwined filaments of Girvanella, Rothpletzella and Wetheredella with Fe-enriched outer walls that generate Frutexites-like microstructures. Types I and II resemble Frutexites sensu stricto as defined by Maslov (Stromatolites, Trudy Instituta geologicheskikh nauk Akademiya nauk SSR, 1960) and are the result of the consecutive growth and permineralisation of biofilms composed of mixed bacterial communities growing in cryptic habitats. Type III superficially resembles Frutexites sensu stricto based on macroscopic field observations, however, detailed microscopic analysis reveals that it is composed of Fe-enriched tubular walls surrounded by Mn-enriched calcite.


Sujet(s)
Bactéries , Carbonate de calcium , Carbonate de calcium/composition chimique , Australie , Microscopie électronique à balayage , Australie occidentale
15.
Jpn J Radiol ; 42(2): 158-164, 2024 Feb.
Article de Anglais | MEDLINE | ID: mdl-37633874

RÉSUMÉ

Recently, computed tomography with photon-counting detector (PCD-CT) has been developed to enable high-resolution imaging at a lower radiation dose. PCD-CT employs a photon-counting detector that can measure the number of incident X-ray photons and their energy. The newly released PCD-CT (NAEOTOM Alpha, Siemens Healthineers, Forchheim, Germany) has been in clinical use at our institution since December 2022. The PCD-CT offers several advantages over current state-of-the-art energy-integrating detector CT (EID-CT). The PCD-CT does not require septa to create a detector channel, while EID-CT does. Therefore, downsizing the anode to achieve higher resolution does not affect the dose efficiency of the PCD-CT. CT is an indispensable modality for evaluating ear ossicles. The ear ossicles and joints are clearly depicted by PCD-CT. In particular, the anterior and posterior legs of the stapes, which are sometimes unclear on conventional CT scans, can be clearly visualized. We present cases of congenital anomalies of the ossicular chain, ossicular chain dislocation, tympanosclerosis, and cholesteatoma in which PCD-CT was useful. This short article reports the usefulness of PCD-CT in the 3D visualization of the ear ossicles.


Sujet(s)
Amélioration d'image radiographique , Tomodensitométrie , Humains , Fantômes en imagerie , Tomodensitométrie/méthodes , Amélioration d'image radiographique/méthodes , Photons , Osselets de l'audition/imagerie diagnostique
16.
Methods Mol Biol ; 2748: 55-72, 2024.
Article de Anglais | MEDLINE | ID: mdl-38070107

RÉSUMÉ

The extracellular matrix (ECM) is a network woven out of more than 1300 different proteins, of which ≈300 are structural. Their presence, distribution, and abundance change between and within tissues. It is also increasingly clear that the ECM is remodeled in disease-specific patterns. The interactions between organ- or disease-specific ECM and resident cells are a subject of intense research and engineering. Precisely mapping the three-dimensional ECM structure across tissues and diseases is therefore a fundamental task. Here, we discuss in situ decellularization of tissues (ISDoT) as an essential tool to map the ECM supporting primary and metastatic tumors in experimental mice.


Sujet(s)
Matrice extracellulaire , Ingénierie tissulaire , Souris , Animaux , Matrice extracellulaire/métabolisme , Ingénierie tissulaire/méthodes , Structures d'échafaudage tissulaires/composition chimique
17.
Phys Med Biol ; 69(1)2023 Dec 26.
Article de Anglais | MEDLINE | ID: mdl-38048627

RÉSUMÉ

Objective.This study aims at investigating a novel super resolution CBCT imaging approach with a dual-layer flat panel detector (DL-FPD).Approach.With DL-FPD, the low-energy and high-energy projections acquired from the top and bottom detector layers contain over-sampled spatial information, from which super-resolution CT images can be reconstructed. A simple mathematical model is proposed to explain the signal formation procedure in DL-FPD, and a dedicated recurrent neural network, named suRi-Net, is developed based upon the above imaging model to nonlinearly retrieve the high-resolution dual-energy information. Physical benchtop experiments are conducted to validate the performance of this newly developed super-resolution CBCT imaging method.Main Results.The results demonstrate that the proposed suRi-Net can accurately retrieve high spatial resolution information from the low-energy and high-energy projections of low spatial resolution. Quantitatively, the spatial resolution of the reconstructed CBCT images from the top and bottom detector layers is increased by about 45% and 54%, respectively.Significance.In the future, suRi-Net will provide a new approach to perform high spatial resolution dual-energy imaging in DL-FPD-based CBCT systems.


Sujet(s)
Apprentissage profond , Tomodensitométrie hélicoïdale à faisceau conique , Tomodensitométrie à faisceau conique/méthodes , Fantômes en imagerie , Tomodensitométrie
18.
Cureus ; 15(11): e48974, 2023 Nov.
Article de Anglais | MEDLINE | ID: mdl-38111406

RÉSUMÉ

Shoulder joint pain is a complex and prevalent clinical concern affecting individuals across various ages and lifestyles. This review delves into the pivotal role of high-resolution imaging techniques, namely ultrasound and magnetic resonance imaging (MRI), in the comprehensive assessment and management of shoulder joint pain. We explore the anatomical foundations of the shoulder, common etiologies of pain, and the significance of precise diagnosis. High-resolution imaging facilitates the identification of various shoulder pathologies and is crucial in treatment planning, surgical interventions, and long-term prognosis assessment. We examine emerging technologies, discuss challenges and limitations, and chart potential future developments, emphasizing the ongoing evolution of imaging in this critical healthcare domain. In conclusion, high-resolution imaging is an indispensable tool, continually advancing to meet the diagnostic and therapeutic needs of individuals grappling with shoulder joint pain.

19.
Int J Mol Sci ; 24(21)2023 Nov 04.
Article de Anglais | MEDLINE | ID: mdl-37958958

RÉSUMÉ

Chromatin is now regarded as a heterogeneous and dynamic structure occupying a non-random position within the cell nucleus, where it plays a key role in regulating various functions of the genome. This current view of chromatin has emerged thanks to high spatiotemporal resolution imaging, among other new technologies developed in the last decade. In addition to challenging early assumptions of chromatin being regular and static, high spatiotemporal resolution imaging made it possible to visualize and characterize different chromatin structures such as clutches, domains and compartments. More specifically, super-resolution microscopy facilitates the study of different cellular processes at a nucleosome scale, providing a multi-scale view of chromatin behavior within the nucleus in different environments. In this review, we describe recent imaging techniques to study the dynamic organization of chromatin at high spatiotemporal resolution. We also discuss recent findings, elucidated by these techniques, on the chromatin landscape during different cellular processes, with an emphasis on the DNA damage response.


Sujet(s)
Chromatine , Nucléosomes , Microscopie , Génome , Noyau de la cellule
20.
Med Phys ; 2023 Nov 28.
Article de Anglais | MEDLINE | ID: mdl-38014777

RÉSUMÉ

BACKGROUND: Misalignment or double-contouring artifacts can appear in high-resolution 3D cone beam computed tomography (CBCT) images, potentially indicating geometric accuracy issues in the projection data. Such artifacts may go unnoticed in low-resolution images and could be associated with changes in the focal spot (FS) position. PURPOSE: High-resolution 3D-CBCT imaging by a mobile imaging device with a large gantry clearance offers more versatility for clinical workflows in image-guided brachytherapy (IGBT), intraoperative radiation therapy (IORT), and spinal, as well as maxillofacial surgery. However, misalignment or double-contouring artifacts hinder workflow advancements in these domains. This paper introduces intrinsic calibration and geometrical correction methods as extensions to a well-established technique for addressing geometrical deviations resulting from factors such as gravity or mechanical inconsistencies. These extensions cover shifts and drifts of the FS depending on FS size selection, temperature, tube current, and tube potential. The proposed methods effectively mitigate artifacts in high-resolution CBCT images stemming from geometrical inaccuracies in projection data, without requiring additional equipment like a pinhole device. METHODS: Geometrical offsets and drifts of the x-ray tube FS were characterized on a mobile multi-purpose imaging system, the ImagingRing-m. A pinhole-like experiment was simulated by adjusting the movable collimation unit to a small rectangular aperture within the FS size range. The influence of filament selection, that is, FS size, temperature, the relatively low tube currents, as well as tube potential settings have been studied on two different monobloc types sharing the same x-ray tube insert. The Catphan 504 and an Alderson head phantom were used to assess resulting image artifacts. RESULTS: Switching the FS size to one different from what was used for geometrical (gravitation, mechanical variations) calibration induced the most notable position changes of the x-ray FS, resulting in double-contouring artifacts and blurring of high-resolution 3D-CBCT images. Incorporating these shifts into a geometrical correction method effectively minimized these artifacts. Thermal drifts exhibited the second largest geometrical changes, comparable to FS size shifts across the thermal operating conditions of the x-ray system. The proposed thermal drift compensation markedly reduced thermal drift effects. Tube current and potential had little impact within the range of available tube currents, eliminating the need for compensation in current applications. CONCLUSIONS: Augmenting the geometrical calibration pipeline with proposed FS drift compensations yielded significant enhancements in image quality for high-resolution reconstructions. While compensation for thermal effects posed challenges, it proved achievable. The roles of tube current and potential were found to be negligible.

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