scholarly journals Chronic Monitoring of Vascular Progression after Ischemic Stroke Using Multiexposure Speckle Imaging and Two-Photon Fluorescence Microscopy

2015 ◽  
Vol 35 (6) ◽  
pp. 933-942 ◽  
Author(s):  
Christian J Schrandt ◽  
SM Shams Kazmi ◽  
Theresa A Jones ◽  
Andrew K Dunn
Keyword(s):  
Imaging Techniques ◽  
Multiphoton Microscopy ◽  
Recovery Process ◽  
Vascular Density ◽  
Speckle Imaging ◽  
Flow Measurements ◽  
Thrombotic Occlusion ◽  
Imaging Protocol ◽  
Volume Fractions ◽  
Two Photon

Monitoring the progression of the vascular structure and cerebral blood flow (CBF) after brain injury is vital to understand the neurovascular recovery process. Multiexposure speckle imaging (MESI) provides a quantitatively accurate technique for chronically measuring the postocclusion CBF perfusion of the infarct and peri-infarct regions in rodent stroke models, while multiphoton microscopy offers direct visualization of the microvascular structure. In this paper, we present imaging outcomes extending 35 days after photo-thrombotic occlusion, tracking the progression of the vasculature throughout this period. We compare MESI flow estimates within the unresolvable parenchyma with subsurface microvascular volume fractions taken with two-photon microscopy in the same regions to assess how the vascular density influences the surface-integrated MESI flow values. The MESI flow measurements and volume fractions are shown to have high correlations (r=0.90) within areas of recovering vasculature in the peri-infarct region. We also observe vascular reorientation occurring within the microvascular structure throughout the 35-day postocclusion period. With the combination of a chronic mouse model and relatively noninvasive optical imaging techniques, we present an imaging protocol for monitoring long-term vascular progression after photo-thrombotic occlusion with the potential to test the efficacy of rehabilitation and pharmacological therapies.

scholarly journals Multiphoton Microscopy for Ophthalmic Imaging

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Emily A. Gibson ◽  
Omid Masihzadeh ◽  
Tim C. Lei ◽  
David A. Ammar ◽  
Malik Y. Kahook
Keyword(s):  
Harmonic Generation ◽  
Second Harmonic ◽  
Imaging Techniques ◽  
Multiphoton Microscopy ◽  
Tissue Imaging ◽  
Third Harmonic ◽  
Two Photon ◽  
Disease Mechanisms ◽  
Ophthalmic Imaging ◽  
Anti Stokes

We review multiphoton microscopy (MPM) including two-photon autofluorescence (2PAF), second harmonic generation (SHG), third harmonic generation (THG), fluorescence lifetime (FLIM), and coherent anti-Stokes Raman Scattering (CARS) with relevance to clinical applications in ophthalmology. The different imaging modalities are discussed highlighting the particular strength that each has for functional tissue imaging. MPM is compared with current clinical ophthalmological imaging techniques such as reflectance confocal microscopy, optical coherence tomography, and fluorescence imaging. In addition, we discuss the future prospects for MPM in disease detection and clinical monitoring of disease progression, understanding fundamental disease mechanisms, and real-time monitoring of drug delivery.

scholarly journals Imaging and SERS Study of the Au Nanoparticles Interaction with HPV and Carcinogenic Cervical Tissues

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3758
Author(s):  
Andrea Ceja-Fdez ◽  
Ramon Carriles ◽  
Ana Lilia González-Yebra ◽  
Juan Vivero-Escoto ◽  
Elder de la Rosa ◽  
...  
Keyword(s):  
Multiphoton Microscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Rapid Screening ◽  
Emission Region ◽  
Sem Images ◽  
Spectral Signatures ◽  
Two Photon ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Gold Nps

In this work, gold NPs were prepared by the Turkevich method, and their interaction with HPV and cancerous cervical tissues were studied by scanning electron microscopy, energy-dispersive x-ray spectroscopy, confocal and multiphoton microscopy and SERS. The SEM images confirmed the presence and localization of the gold NPs inside of the two kinds of tissues. The light absorption of the gold NPs was at 520 nm. However, it was possible to obtain two-photon imaging (red emission region) of the gold NPs inside of the tissue, exciting the samples at 900 nm, observing the morphology of the tissues. The infrared absorption was probably due to the aggregation of gold NPs inside the tissues. Therefore, through the interaction of gold nanoparticles with the HPV and cancerous cervical tissues, a surface enhanced Raman spectroscopy (SERS) was obtained. As preliminary studies, having an average of 1000 Raman spectra per tissue, SERS signals showed changes between the HPV-infected and the carcinogenic tissues; these spectral signatures occurred mainly in the DNA bands, potentially offering a tool for the rapid screening of cancer.

Intravital multiphoton microscopy of dynamic renal processes

2005 ◽  
Vol 288 (6) ◽  
pp. F1084-F1089 ◽  
Author(s):  
Bruce A. Molitoris ◽  
Ruben M. Sandoval
Keyword(s):  
Proximal Tubule ◽  
Multiphoton Microscopy ◽  
Field Of View ◽  
Glomerular Permeability ◽  
Structural Alterations ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Dynamic Events ◽  
Subcellular Resolution ◽  
Functioning Kidney

Recent advances in microscopy and optics, computer sciences, and the available fluorophores used to label molecules of interest have empowered investigators to utilize intravital two-photon microscopy to study the dynamic events within the functioning kidney. This emerging technique enables investigators to follow functional and structural alterations with subcellular resolution within the same field of view over seconds to weeks. This approach invigorates the validity of data and facilitates analysis and interpretation as trends are more readily determined when one is more closely monitoring indicative physiological parameters. Therefore, in this review we emphasize how specific approaches will enable studies into glomerular permeability, proximal tubule endocytosis, and microvascular function within the kidney. We attempt to show how visual data can be quantified, thus allowing enhanced understanding of the process under study. Finally, emphasis is given to the possible future opportunities of this technology and its present limitations.

scholarly journals Respiratory-gated KES imaging of a rat model of acute lung injury at the Canadian Light Source

2017 ◽  
Vol 24 (3) ◽  
pp. 679-685 ◽  
Author(s):  
P. Deman ◽  
S. Tan ◽  
G. Belev ◽  
N. Samadi ◽  
M. Martinson ◽  
...  
Keyword(s):  
Lung Injury ◽  
Contrast Agent ◽  
Light Source ◽  
Imaging Techniques ◽  
Image Acquisition ◽  
Brown Norway ◽  
Pulmonary Vasculature ◽  
Imaging Method ◽  
Imaging Protocol ◽  
Iodinated Contrast

In this study, contrast-enhanced X-ray tomographic imaging for monitoring and quantifying respiratory disease in preclinical rodent models is proposed. A K-edge imaging method has been developed at the Canadian Light Source to very accurately obtain measurements of the concentration of iodinated contrast agent in the pulmonary vasculature and inhaled xenon in the airspaces of rats. To compare the iodine and xenon concentration maps, a scout projection image was acquired to define the region of interest within the thorax for imaging and to ensure the same locations were imaged in each K-edge subtraction (KES) acquisition. A method for triggering image acquisition based on the real-time measurements of respiration was also developed to obtain images during end expiration when the lungs are stationary, in contrast to other previously published studies that alter the respiration to accommodate the image acquisition. In this study, images were obtained in mechanically ventilated animals using physiological parameters at the iodine K-edge in vivo and at the xenon K-edge post mortem (but still under mechanical ventilation). The imaging techniques were performed in healthy Brown Norway rats and in age-matched littermates that had an induced lung injury to demonstrate feasibility of the imaging procedures and the ability to correlate the lung injury and the quantitative measurements of contrast agent concentrations between the two KES images. The respiratory-gated KES imaging protocol can be easily adapted to image during any respiratory phase and is feasible for imaging disease models with compromised lung function.

scholarly journals Extended depth of focus multiphoton microscopy via incoherent pulse splitting

2020 ◽  
Author(s):  
Bingying Chen ◽  
Tonmoy Chakraborty ◽  
Stephan Daetwyler ◽  
James D. Manton ◽  
Kevin Dean ◽  
...  
Keyword(s):  
Multiphoton Microscopy ◽  
Laser Pulses ◽  
Low Complexity ◽  
Phase Mask ◽  
Light Sources ◽  
Depth Of Focus ◽  
Ultrafast Laser Pulses ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
Extended Depth Of Focus

AbstractWe present a phase mask that can be easily added to any multi-photon raster scanning microscope to extend the depth of focus five-fold at a small loss in lateral resolution. The method is designed for ultrafast laser pulses or other light-sources featuring a low coherence length. In contrast to other methods of focus extension, our approach uniquely combines low complexity, high light-throughput and multicolor capability. We characterize the point-spread function in a two-photon microscope and demonstrate fluorescence imaging of GFP labeled neurons in fixed brain samples as imaged with conventional and extended depth of focus two-photon microscopy.

scholarly journals Role of Imaging in Diagnosis and Management of COVID-19: A Multiorgan Multimodality Imaging Review

2021 ◽  
Vol 8 ◽  
Author(s):  
Vinithra Varadarajan ◽  
Mahsima Shabani ◽  
Bharath Ambale Venkatesh ◽  
Joao A. C. Lima
Keyword(s):  
Multimodality Imaging ◽  
Imaging Techniques ◽  
Standard Of Care ◽  
Review Article ◽  
Health Centers ◽  
Imaging Modalities ◽  
Imaging Protocol ◽  
Diagnosis And Management ◽  
Radiologic Findings

In this pandemic of Coronavirus disease 2019 (COVID-19), a vast proportion of healthcare resources, including imaging tools, have been dedicated to the management of affected patients; yet, the frequent reports of unknown presentations and complications of disease over time have been changing the usual standard of care and resource allocation in health centers. As of now, we have witnessed multisystemic symptoms requiring the collaboration of different clinical teams in COVID-19 patients' care. Compared to previous viral pandemics, imaging modalities are now playing an essential role in the diagnosis and management of patients. This widespread utility of imaging modalities calls for a deeper understanding of potential radiologic findings in this disease and identifying the most compatible imaging protocol with safety precautions. Although initially used for respiratory tract evaluation, imaging modalities have also been used for cardiovascular, neurologic, and gastrointestinal evaluation of patients with COVID-19. In this narrative review article, we provide multimodality and multisystemic review of imaging techniques and features that can aid in the diagnosis and management of COVID-19 patients.

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