Scanning Laser Ophthalmoscopy

2017 ◽  
pp. 18-21
Keyword(s):  
Light Intensity ◽  
Laser Beam ◽  
Imaging Technique ◽  
Morphological Changes ◽  
Imaging Techniques ◽  
Tissue Level ◽  
Scanning Laser ◽  
Scanning Laser Ophthalmoscopy ◽  
Imaging Device ◽  
Scanning Laser Microscopy

The aim of retinal imaging techniques is visualization of morphological changes at the cellular and tissue level. Various techniques are used for this purpose. The scanning laser ophthalmoscopy (SLO), a retinal optical imaging device based on standard scanning laser microscopy is an imaging technique that scans the fundus with a highly collimated narrow laser beam and measures the backscattered light intensity. Here, progress on developing SLO instruments and their applications in ophthalmology are reviewed.

scholarly journals An Alternative Phase-Sensitive THz Imaging Technique for Art Conservation: History and New Developments at the ENEA Center of Frascati

2020 ◽  
Vol 10 (21) ◽  
pp. 7661
Author(s):  
Andrea Doria ◽  
Gian Piero Gallerano ◽  
Emilio Giovenale ◽  
Luca Senni ◽  
Manuel Greco ◽  
...  
Keyword(s):  
Optical Properties ◽  
Free Electron ◽  
Imaging Technique ◽  
Imaging Techniques ◽  
Dielectric Materials ◽  
Art Conservation ◽  
Alternative Technique ◽  
Thz Imaging ◽  
Imaging Device ◽  
Conservation History

In recent years, THz imaging techniques have been used in several fields of application. At the beginning of the century, the low availability of powerful THz sources was one of the limiting factors to the advancement of THz technology. At the ENEA center in Frascati, two Free Electron Lasers (FELs) operating in the THz spectral region were available at that time, making it possible to exploit all the features of THz imaging. In this paper, we will describe an alternative THz imaging technique, developed over 15 years of studies at the ENEA center of Frascati, and its application in the art conservation field, reporting the latest results of such studies on the optical properties of pigments in the GHz-THz region of the spectrum, on the possibility of detecting biological weeds under mosaic tiles and on the THz analysis of ancient leather wallpapers. This alternative technique was first developed in the framework of a bilateral collaboration between Japan and Italy, the THz-ARTE Project, which involved NICT (Tokyo), NNRICP (Nara), ENEA (Frascati) and IFAC-CNR (Florence). Most of the THz imaging techniques at that time were based on THz-Time Domain (THz-TD) devices. In the paper will be described how this alternative technique is able to measure the phase of the reflected radiation, thus providing information on the optical properties of the materials under study, such as mural paintings and mosaics. This makes it possible to detect the presence of hidden artworks, additional elements under paint layers, and dielectric materials. To describe the potential and the limits of this alternative imaging technique we will start from a description of the first THz imaging setup at the ENEA center of Frascati, based upon a THz Free Electron Laser. A description of the theoretical principle underlying this technique will be given. The first results in the field of art conservation are summarized, while the new results of a systematic study on the optical properties of pigments are reported and the realization of a portable THz imaging device, and its application “on site” for the analysis of frescoes are shown. The success of this prototype lead to the identification of different types of artworks as possible targets to be studied. New results about the ability of detecting water, and possibly the water content of biological weeds, under mosaic tiles are described, while new experimental measurements on Leather Wallpapers, both “in situ” and in a laboratory environment, are discussed later. A final analysis on the pro and the cons of this alternative imaging technique and on its possible utilization with the developed prototype is carried out together with the considerations on possible future developments and its potential use as an extension of other imaging techniques.

scholarly journals Myopic retinal changes screening: comparison of sensitivity and specificity among 15 combinations of ultrawide field scanning laser ophthalmoscopy images

2021 ◽  
Author(s):  
Xuan Deng ◽  
Silvia Tanumiharjo ◽  
Qianyin Chen ◽  
Shengnan Li ◽  
Huimin Lin ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Confidence Interval ◽  
Diagnostic Test ◽  
Scanning Laser ◽  
Test Accuracy ◽  
Scanning Laser Ophthalmoscopy ◽  
Reference Standard ◽  
High Performing ◽  
Primary Screening ◽  
Optimal Evaluation

Aims: To investigate the evaluation indices (diagnostic test accuracy and agreement) of 15 combinations of ultrawide field scanning laser ophthalmoscopy (UWF SLO) images in myopic retinal changes (MRC) screening to determine the combination of imaging that yields the highest evaluation indices in screening MRC. Methods: This is a retrospective study of UWF SLO images obtained from myopes and were analyzed by two retinal specialists independently. 5-field UWF SLO images that included the posterior (B), superior (S), inferior (I), nasal (N) and temporal (T) regions were obtained for analysis and its results used as a reference standard. The evaluation indices of different combinations comprising of one to four fields of the retina were compared to determine the abilities of each combinations screen for MRC. Results: UWF SLO images obtained from 823 myopic patients (1646 eyes) were included for the study. Sensitivities ranged from 50.0% to 98.9% (95% confidence interval (CI), 43.8-99.7%); the combinations of B+S+I (97.3%; 95% CI, 94.4-98.8%), B+T+S+I (98.5%; 95% CI, 95.9-99.5%), and B+S+N+I (98.9%; 95% CI, 96.4-99.7%) ranked highest. Furthermore, the combinations of B+S+I, B+T+S+I and B+S+N+I also revealed the highest accuracy (97.7%; 95% CI, 95.1-100.0%, 98.6%; 95% CI, 96.7-100.0%, 98.8%; 95% CI, 96.9-100.0%) and agreement (Kappa = 0.968, 0.980 and 0.980). For the various combinations, specificities were all higher than 99.5% (95% CI, 99.3-100.0%). Conclusion: In our study, screening combinations of B+S+I, B+T+S+I and B+S+N+I stand out with high-performing optimal evaluation indices. However, when time is limited, B+S+I may be more applicable in primary screening of MRC.

scholarly journals Design and Synthesis of Luminescent Lanthanide-Based Bimodal Nanoprobes for Dual Magnetic Resonance (MR) and Optical Imaging

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 354
Author(s):  
Walid Mnasri ◽  
Mahsa Parvizian ◽  
Souad Ammar-Merah
Keyword(s):  
Magnetic Resonance ◽  
Optical Imaging ◽  
Imaging Technique ◽  
Imaging Techniques ◽  
Design And Synthesis ◽  
Bimodal Imaging ◽  
Successive Image ◽  
Complete Set ◽  
Magnetic Resonance Imaging Mri ◽  
Physical And Chemical

Current biomedical imaging techniques are crucial for the diagnosis of various diseases. Each imaging technique uses specific probes that, although each one has its own merits, do not encompass all the functionalities required for comprehensive imaging (sensitivity, non-invasiveness, etc.). Bimodal imaging methods are therefore rapidly becoming an important topic in advanced healthcare. This bimodality can be achieved by successive image acquisitions involving different and independent probes, one for each mode, with the risk of artifacts. It can be also achieved simultaneously by using a single probe combining a complete set of physical and chemical characteristics, in order to record complementary views of the same biological object at the same time. In this scenario, and focusing on bimodal magnetic resonance imaging (MRI) and optical imaging (OI), probes can be engineered by the attachment, more or less covalently, of a contrast agent (CA) to an organic or inorganic dye, or by designing single objects containing both the optical emitter and MRI-active dipole. If in the first type of system, there is frequent concern that at some point the dye may dissociate from the magnetic dipole, it may not in the second type. This review aims to present a summary of current activity relating to this kind of dual probes, with a special emphasis on lanthanide-based luminescent nano-objects.

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