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[Ocular Trauma] Anatomy and Examination in Ocular Trauma || Imaging Examination
摘要： Technology advances at a great pace. Particularly in medicine and, one may venture to say, even more so in the field of ophthalmology. Yet, regarding ocular trauma, the physician stands between multiple crossroads when deciding which imaging examination method to choose from. He must find balance between cost-benefit, medicolegal purposes, immediate or intermediate availability, and prioritizing strategy-modifying information, more often than not relying on century-old techniques, mixed with state-of-the-art technologies, and always based on solid clinical evaluation to make the best decision in a reasonably short time. This chapter will attempt to introduce the imaging examination techniques of X-ray, computed tomography scan, magnetic resonance imaging, B-ultrasound, biomicroscopy, optical coherence tomography, and specular microscopy now available for the assessment in ocular trauma, their working mechanisms, scopes, as well as their strong and weak points.
关键词： Computed tomography scan,Ocular trauma,Magnetic resonance imaging,B-ultrasound,Optical coherence tomography,Specular microscopy,Examination,X-ray,Biomicroscopy,UBM
更新于2025-09-10 09:29:36
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Posterior Eye Shape Measurement With Retinal OCT Compared to MRI
摘要： PURPOSE. Posterior eye shape assessment by magnetic resonance imaging (MRI) is used to study myopia. We tested the hypothesis that optical coherence tomography (OCT), as an alternative, could measure posterior eye shape similarly to MRI. METHODS. Macular spectral-domain OCT and brain MRI images previously acquired as part of the Singapore Epidemiology of Eye Diseases study were analyzed. The right eye in the MRI and OCT images was automatically segmented. Optical coherence tomography segmentations were corrected for optical and display distortions requiring biometry data. The segmentations were ?tted to spheres and ellipsoids to obtain the posterior eye radius of curvature (Rc) and asphericity (Qxz). The differences in Rc and Qxz measured by MRI and OCT were tested using paired t-tests. Categorical assignments of prolateness or oblateness using Qxz were compared. RESULTS. Fifty-two subjects (67.8 6 5.6 years old) with spherical equivalent refraction from t0.50 to (cid:2)5.38 were included. The mean paired difference between MRI and original OCT posterior eye Rc was 24.03 6 46.49 mm (P ? 0.0005). For corrected OCT images, the difference in Rc decreased to (cid:2)0.23 6 2.47 mm (P ? 0.51). The difference between MRI and OCT asphericity, Qxz, was (cid:2)0.052 6 0.343 (P ? 0.28). However, categorical agreement was only moderate (j ? 0.50). CONCLUSIONS. Distortion-corrected OCT measurements of Rc and Qxz were not statistically signi?cantly different from MRI, although the moderate categorical agreement suggests that individual differences remained. This study provides evidence that with distortion correction, noninvasive of?ce-based OCT could potentially be used instead of MRI for the study of posterior eye shape.
关键词： asphericity,optical coherence tomography,magnetic resonance imaging,myopia
更新于2025-09-10 09:29:36
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Disturbed interhemispheric functional connectivity in visual pathway in individuals with unilateral retinal detachment: A resting state fMRI study
摘要： Previous neuroimaging studies demonstrated that retinal detachment (RD) subjects were associated with abnormal spontaneous brain activities; however, whether the altered interhemispheric functional connectivity (FC) occurred in RD patients remains unknown. The current study tried to explore the alternations of interhemispheric FC of the whole brain in unilateral RD patients using the voxel-mirrored homotopic connectivity (VMHC) method and their connections to clinical features. Methods: We recruited 30 patients with RD (16 males and 14 females) and 30 healthy controls (HCs) (16 males and 14 females) whose age and sex were closely matched. All subjects underwent the rs-fMRI scans. The VMHC method was applied to directly assess the hemispheres’ functional interaction. The VMHC in these brain areas, which could be used as biomarkers to differentiate RD from HC, was identified by the receiver operating characteristic (ROC) curve analyses. The relations between these patients’ clinical features and their mean VMHC signal values in multiple brain regions were calculated by Pearson correlation analysis. Results: RD patients had significantly lower VMHC values than HCs in the bilateral occipital lobe (Brodmann areas, BA 18), bilateral superior temporal gyrus (BA 39), and bilateral cuneus (BA 19). Moreover, the mean VMHC signal values of the bilateral cuneus were in positive correlation with the duration of the RD (r = 0.446, P = 0.013). Conclusion: Our results provided an evidence of disturbed interhemispheric FC in the visual area occurred in RD patients, which might provide some useful information to understand the neural mechanism of RD patients with acute vision loss. Furthermore, the VMHC values might indicate the progress of the RD.
关键词： Retinal detachment,Functional magnetic resonance imaging,Static condition,Voxel-mirrored homotopic connectivity
更新于2025-09-10 09:29:36
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[IEEE 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Espoo, Finland (2018.8.27-2018.9.1)] 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials) - Tunability methods for magnetic resonance imaging applications of metasurfaces
摘要： In this work, we propose and discuss methods of tuning eigenmode resonance frequencies of wire metasurfaces. Fine tuning of metasurface properties is essential for maximizing its coupling with transmitting and receiving radiofrequency (RF) coils of a magnetic resonance imaging (MRI) system. We have studied numerically and experimentally two designs of metasurfaces with different tunability mechanisms. The first design is a hybrid structure based on periodic wires with extremities penetrating high-permittivity dielectric volumes, where tunability achieved by changing properties of the dielectric parts. The second metasurface is formed by an array of capacitively loaded telescopic wires that permit to adjust the eigenmode resonance frequencies by mechanical expansion of the wires. Both metasurfaces demonstrated the spectacular capability to locally enhance the magnetic field of an external RF coil being precisely tuned to the Larmor frequency of a clinical MRI scanner.
关键词： metasurfaces,RF coils,tunability,eigenmode resonance frequencies,magnetic resonance imaging
更新于2025-09-09 09:28:46
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Integrated Whole Body MR/PET: Where Are We?
摘要： Whole body integrated magnetic resonance imaging (MR)/positron emission tomography (PET) imaging systems have recently become available for clinical use and are currently being used to explore whether the combined anatomic and functional capabilities of MR imaging and the metabolic information of PET provide new insight into disease phenotypes and biology, and provide a better assessment of oncologic diseases at a lower radiation dose than a CT. This review provides an overview of the technical background of combined MR/PET systems, a discussion of the potential advantages and technical challenges of hybrid MR/PET instrumentation, as well as collection of possible solutions. Various early clinical applications of integrated MR/PET are also addressed. Finally, the workflow issues of integrated MR/PET, including maximizing diagnostic information while minimizing acquisition time are discussed.
关键词： Positron emission tomography,MR/PET,Magnetic resonance imaging,Hybrid imaging
更新于2025-09-09 09:28:46
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Single-Breath-Hold Whole-heart Unenhanced Coronary MRA Using Multi-shot Gradient Echo EPI at 3T: Comparison with Free-breathing Turbo-field-echo Coronary MRA on Healthy Volunteers
摘要： We investigated the feasibility of single breath hold unenhanced coronary MRA using multi-shot gradient echo planar imaging (MSG-EPI) on a 3T-scanner. Methods: Fourteen volunteers underwent single breath hold coronary MRA with a MSG-EPI and free-breathing turbo field echo (TFE) coronary MRA at 3T. The acquisition time, signal to noise ratio (SNR), and the contrast of the sequences were compared with the paired t-test. Readers evaluated the image contrast, noise, sharpness, artifacts, and the overall image quality. Results: The acquisition time was 88.1% shorter for MSG-EPI than TFE (24.7 ± 2.5 vs 206.4 ± 23.1 sec, P < 0.01). The SNR was significantly higher on MSG-EPI than TFE scans (P < 0.01). There was no significant difference in the contrast on MSG-EPI and TFE scans (1.8 ± 0.3 vs 1.9 ± 0.3, P = 0.24). There was no significant difference in image contrast, image sharpness, and overall image quality between two scan techniques. The score of image noise and artifact were significantly higher on MSG-EPI than TFE scans (P < 0.05). Conclusion: The single breath hold MSG-EPI sequence is a promising technique for shortening the scan time and for preserving the image quality of unenhanced whole heart coronary MRA on a 3T scanner.
关键词： men,coronary angiography,respiration,magnetic resonance imaging
更新于2025-09-09 09:28:46
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[SpringerBriefs in Applied Sciences and Technology] Internet of Things and Personalized Healthcare Systems || Role of Imaging Modality in Premature Detection of Bosom Irregularity
摘要： Since last 60 years, bosom (breast) tumor is the major cause of death amid females worldwide. Earliest possible detection will raise the endurance rate of patients. Premature detection of bosom tumor is big challenge in medical science. Medical studies proven that imaging modalities like mammography, thermography, ultrasound, and magnetic resonance imaging (MRI) play a vigorous role to detect breast irregularity earliest. This paper enhances the knowledge on two imaging practices, one is mammography and another is thermography. It aids to identify the limitations in existing technologies and helps to plan the new methodology.
关键词： Bosom tumor,Ultrasound,MRI—magnetic resonance imaging,Mammography,Thermography
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - SIRF: Synergistic Image Reconstruction Framework
摘要： The combination of positron emission tomography (PET) with magnetic resonance (MR) imaging opens the way to more accurate diagnosis and improved patient management. At present, the data acquired by PET and MR scanners are essentially processed separately, and the search for ways to improve accuracy of the tomographic reconstruction via synergy of the two imaging techniques is an active area of research. The aim of the collaborative computational project on PET and MR (CCP-PETMR), supported by the UK engineering and physical sciences research council (EPSRC), is to accelerate research in synergistic PET-MR image reconstruction by providing an open access software platform for efficient implementation and validation of novel reconstruction algorithms. In this paper, we present the first release of the Synergistic Image Reconstruction Framework (SIRF) software suite from the CCP-PETMR. SIRF provides user-friendly Python and MATLAB interfaces to advanced PET and MR reconstruction packages written in C++ (currently this uses STIR, Software for Tomographic Image Reconstruction, for PET and Gadgetron for MR, but SIRF will be able to link to other reconstruction engines in the future as appropriate). The software is capable of reconstructing images from real scanner data. Both of the available integrated clinical PET-MR systems (Siemens and GE) are being targeted, and a suitable data format exchange is being negotiated with the manufacturers.
关键词： Magnetic Resonance Imaging,Research Software Engineering,Scientific Programming,Positron Emission Tomography
更新于2025-09-09 09:28:46
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Imaging as a Personalized Biomarker for Prostate Cancer Risk Stratification
摘要： Biomarkers provide objective data to guide clinicians in disease management. Prostate-specific antigen serves as a biomarker for screening of prostate cancer but has come under scrutiny for detection of clinically indolent disease. Multiple imaging techniques demonstrate promising results for diagnosing, staging, and determining definitive management of prostate cancer. One such modality, multiparametric magnetic resonance imaging (mpMRI), detects more clinically significant disease while missing lower volume and clinically insignificant disease. It also provides valuable information regarding tumor characteristics such as location and extraprostatic extension to guide surgical planning. Information from mpMRI may also help patients avoid unnecessary biopsies in the future. It can also be incorporated into targeted biopsies as well as following patients on active surveillance. Other novel techniques have also been developed to detect metastatic disease with advantages over traditional computer tomography and magnetic resonance imaging, which primarily rely on defined size criteria. These new techniques take advantage of underlying biological changes in prostate cancer tissue to identify metastatic disease. The purpose of this review is to present literature on imaging as a personalized biomarker for prostate cancer risk stratification.
关键词： magnetic resonance imaging (MRI),cancer staging,active surveillance,radical prostatectomy,Gleason score,radiation therapy
更新于2025-09-09 09:28:46
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Lanthanide-doped Hafnia Nanoparticles for Multimodal Theranostics: Tailoring the Physicochemical Properties and Interactions with Biological Entities
摘要： High-Z metal oxide nanoparticles hold promise as imaging probes and radio-enhancers. Hafnium dioxide nanoparticles have recently entered clinical evaluation. Despite promising early clinical findings, the potential of HfO2 as a matrix for multimodal theranostics is yet to be developed. Here, we investigate the physicochemical properties and the potential of HfO2-based nanoparticles for multimodal theranostic imaging. Undoped and lanthanide (Eu3+, Tb3+, and Gd3+)-doped HfO2 nanoparticles were synthesized and functionalized with various moieties, including poly(vinylpyrrolidone) (PVP), (3-aminopropyl)triethoxysilane (APTES) and folic acid (FA). We show that different synthesis routes, including direct precipitation, microwave-assisted synthesis, and sol-gel chemistry allow preparation of hafnium dioxide particles with distinct physicochemical properties. Sol-gel based synthesis allows preparation of uniform nanoparticles with dopant incorporation efficiencies superior to the other two methods. Both luminescence and contrast properties can be tweaked by lanthanide doping. We show that MRI contrast can be unified with radio-enhancement by incorporating lanthanide dopants in the HfO2 matrix. Importantly, ion leaching from the HfO2 host matrix in lysosomal-like conditions was minimal. For Gd:HfO2 nanoparticles, leaching was reduced >10× compared to Gd2O3 and no relevant cytotoxic effects have been observed in monocyte-derived macrophages for nanoparticle concentrations up to 250 μg/mL. Chemical surface modification allows further tailoring of the cyto- and hemocompatibility and enables functionalization with molecular targeting entities, which lead to enhanced cellular uptake. Taken together, the present study illustrates the manifold properties of HfO2-based nanomaterials with prospective clinical utility beyond radio-enhancement.
关键词： x-ray,magnetic resonance imaging,functionalization,bioimaging,hafnium dioxide
更新于2025-09-09 09:28:46