Development of a Deep Learning-Based System for Optic Nerve Characterization in Transorbital Ultrasound Images on a Multicenter Data Set.

Objective: Characterization of the optic nerve through measurement of optic nerve diameter (OND) and optic nerve sheath diameter (ONSD) using transorbital sonography (TOS) has proven to be a useful tool for the evaluation of intracranial pressure (ICP) and multiple neurological conditions. We describe a deep learning-based system for automatic characterization of the optic nerve from B-mode TOS images by automatic measurement of the OND and ONSD. In addition, we determine how the signal-to-noise ratio in two different areas of the image influences system performance.

Effect of physical stimuli on hair follicle deposition of clobetasol-loaded Lipid Nanocarriers.

Clobetasol propionate (CLO) is a potent glucocorticoid used to treat inflammation-based skin, scalp, and hair disorders. In such conditions, hair follicles (HF) are not only the target site but can also act as drug reservoirs when certain formulations are topically applied. Recently, we have demonstrated nanostructured lipid carriers (NLC) containing CLO presenting epidermal-targeting potential.

Simulation and Experimental Characterization of Lateral Imaging Resolution of Ultrasound Systems and Assessment of System Suitability for Acoustic Optic Nerve Sheath Diameter Measurement.

Background And Purpose: Optic nerve sheath diameter (ONSD) is used for the estimation of intracranial pressure (ICP). But there are still doubts about the quality of the images and the lateral resolution. Our aim is to investigate the system suitability and best lateral resolution of different ultrasound systems for acoustic ONSD measurement.

Tissue-Mimicking Geometrical Constraints Stimulate Tissue-Like Constitution and Activity of Mouse Neonatal and Human-Induced Pluripotent Stem Cell-Derived Cardiac Myocytes.

The present work addresses the question of to what extent a geometrical support acts as a physiological determining template in the setup of artificial cardiac tissue. Surface patterns with alternating concave to convex transitions of cell size dimensions were used to organize and orientate human-induced pluripotent stem cell (hIPSC)-derived cardiac myocytes and mouse neonatal cardiac myocytes. The shape of the cells, as well as the organization of the contractile apparatus recapitulates the anisotropic line pattern geometry being derived from tissue geometry motives.

Optoacoustic imaging of subcutaneous microvasculature with a class one laser.

We developed a combined imaging platform allowing optoacoustic and ultrasound imaging based on a low energy laser and a handheld probe. The device is based on a sensitive single element 35-MHz focused transducer, a 2-D piezoscanner and a dual-wavelength switchable Nd:YAG laser. Acoustical detection and optical illumination are confocal for optimization of optoacoustic signal-to-noise ratio.

Comparison of the optoacoustic signal generation efficiency of different nanoparticular contrast agents.

Optoacoustic imaging represents a new modality that allows noninvasive in vivo molecular imaging with optical contrast and acoustical resolution. Whereas structural or functional imaging applications such as imaging of vasculature do not require contrast enhancing agents, nanoprobes with defined biochemical binding behavior are needed for molecular imaging tasks. Since the contrast of this modality is based on the local optical absorption coefficient, all particle or molecule types that show significant absorption cross sections in the spectral range of the laser wavelength used for signal generation are suitable contrast agents.

Fluorescence response of human HER2+ cancer- and MCF-12F normal cells to 200MHz ultrasound microbeam stimulation: a preliminary study of membrane permeability variation.

Targeted mechanical cell stimulation has been extensively studied for a better understanding of its effect on cellular mechanotransduction signaling pathways and structures by utilizing a variety of mechanical sources. In this work, an ultrasound-driven single cell stimulation method is thus proposed, and a preliminary study is carried out by comparing the fluorescence intensities representing a change in cell membrane permeability between MDA-MB-435 human HER2+ cancer cells (∼40-50μm in diameter) and MCF-12F normal cells (∼50-60μm) in the presence of ultrasound. A 200MHz single element zinc oxide (ZnO) transducer is employed to generate ultrasound microbeam (UM) whose beamwidth and depth of focus are 9.

Antitumor necrosis factor-α antibody-coupled gold nanorods as nanoprobes for molecular optoacoustic imaging in arthritis.

Optoacoustic molecular imaging can provide spatially resolved information about the presence of molecular markers in vivo. We synthesized elongated gold nanorods having an absorption maximum in the range of 1064 nm modified with the antibodies infliximab and certolizumab for targeting TNF-α to detect inflammation in arthritic mouse knees. We showed an differential enhancement of optoacoustic signal amplitudes after the injection of infliximab-, but not certolizumab-modified and PEGylated control particles on arthritic and healthy control mice by using a fast-scanning optoacoustic imaging platform based on a pulsed Nd:YAG laser and a single focused ultrasound transducer.

Near-infrared dye-loaded PLGA nanoparticles prepared by spray drying for photoacoustic applications.

Introduction: Nanoparticulate contrast agents are of great interest for diagnostic applications with high resolution in medicine. Here we present polymer-based degradable nanoparticles exhibiting a near infrared (NIR) absorption suitable for photoacoustic imaging.

Methods: The nanoparticles were prepared by incorporation of indocyanine green (ICG) as NIR dye in poly[(rac-lactide)-co-glycolide] (PLGA) via an optimized spray drying process.

Targeted cell immobilization by ultrasound microbeam.

Various techniques exerting mechanical stress on cells have been developed to investigate cellular responses to externally controlled stimuli. Fundamental mechanotransduction processes about how applied physical forces are converted into biochemical signals have often been examined by transmitting such forces through cells and probing its pathway at cellular levels. In fact, many cellular biomechanics studies have been performed by trapping (or immobilizing) individual cells, either attached to solid substrates or suspended in liquid media.

Preparation and biological evaluation of multifunctional PLGA-nanoparticles designed for photoacoustic imaging.

Unlabelled: Nanoparticulate contrast agents for molecular imaging have attracted widespread interest for diagnostic applications with high resolution in medicine. Here we introduce polymer-based multifunctional nanoparticles exhibiting a near-infrared absorption in the range of the Nd:YAG laser wavelength of 1064 nm as a novel resorbable photoacoustic (PA) contrast system and report about their biological evaluation. Submicron-sized spherical nanoparticles with a high encapsulation efficiency (>87%) were created by incorporation of near-infrared dyes (IR5/IR26) in poly[(rac-lactide)-co-glycolide] (PLGA) with 50 mol% glycolide content via a specific spray-drying process in good yield (>75%).

High frequency optoacoustic microscopy.

Photoacoustic imaging--also called optoacoustic imaging--is a new hybrid modality of high tissue contrast which is based on the varying optical properties of tissue. The acoustic signal generated by pulsed laser absorption reports tissue-specific information with high spatial resolution. To increase the intrinsic contrast in tissue, absorbing particles are of great interest for optical imaging because of their considerable capacity to absorb and scatter light at visible and near-infrared wavelengths.

High frequency ultrasound tissue characterization and acoustic microscopy of intracellular changes.

The objective of this work is to investigate changes in the acoustic properties of cells when exposed to chemotherapy for monitoring treatment response. High frequency ultrasound spectroscopy (10-60 MHz) and scanning acoustic microscopy (0.9 GHz) were performed on HeLa cells (Ackermann et al.

Mechanical properties of single cells by high-frequency time-resolved acoustic microscopy.

In this paper, we describe a new, high-frequency, time-resolved scanning acoustic microscope developed for studying dynamical processes in biological cells. The new acoustic microscope operates in a time-resolved mode. The center frequency is 0.

Subunits alpha, beta and gamma of the epithelial Na+ channel (ENaC) are functionally related to the hypertonicity-induced cation channel (HICC) in rat hepatocytes.

Specific small interfering RNA (siRNA) constructs were used to test for the functional relation of subunits alpha, beta, and gamma of the epithelial Na(+) channel (ENaC) to the hypertonicity-induced cation channel (HICC) in confluent rat hepatocytes. In current-clamp recordings, hypertonic stress (300 --> 400 mosM) increased membrane conductance from 75.4 +/- 9.

Imaging of focal contacts of chicken heart muscle cells by high-frequency acoustic microscopy.

A study of the adhesion of embryonic chicken heart muscle cells was conducted with a newly developed time-resolved acoustic microscope, which operates in the GHz-frequency range. The interpretation of the acoustical images of the heart muscle cells was done in combination with the fluorescence optical microscopy. A comparison between the acoustical images of chicken heart muscle cells and optical images of the same cells after staining showed that the actin fibers end inside the dark streaks in the acoustical images and thus represent the focal contacts (FCs).

In-vivo observation of cells with a combined high-resolution multiphoton-acoustic scanning microscope.

We present a combined multiphoton-acoustic microscope giving collocated access to the local morphological as well as mechanical properties of living cells. Both methods relay on intrinsic contrast mechanisms and dispense with the need of staining. In the acoustic part of the microscope, a gigahertz ultrasound wave is generated by an acoustic lens and the reflected sound energy is detected by the identical lens in a confocal setup.

Combined ultrasound and optoacoustic system for real-time high-contrast vascular imaging in vivo.

In optoacoustic imaging, short laser pulses irradiate highly scattering human tissue and adiabatically heat embedded absorbing structures, such as blood vessels, to generate ultrasound transients by means of the thermoelastic effect. We present an optoacoustic vascular imaging system that records these transients on the skin surface with an ultrasound transducer array and displays the images online. With a single laser pulse a complete optoacoustic B-mode image can be acquired.