Mechanism of Amplified Photoacoustic Effect for Silica-Coated Spherical Gold Nanoparticles.

Plasmonic nanomaterials are effective photoacoustic (PA) contrast agents with diverse biomedical applications. While silica coatings on gold nanoparticles (AuNPs) have been demonstrated to increase PA efficiency, the underlying mechanism remains elusive. Here, we systematically investigated the impact of silica coatings on PA generation under picosecond and nanosecond laser pulses.

Multiparametric ultrasound imaging for early-stage steatosis: Comparison with magnetic resonance imaging-based proton density fat fraction.

Background: The prevalence of liver diseases, especially steatosis, requires a more convenient and noninvasive tool for liver diagnosis, which can be a surrogate for the gold standard biopsy. Magnetic resonance (MR) measurement offers potential, however ultrasound (US) has better accessibility than MR.

Purpose: This study aims to suggest a multiparametric US approach which demonstrates better quantification and imaging performance than MR imaging-based proton density fat fraction (MRI-PDFF) for hepatic steatosis assessment.

Image-guided focused ultrasound-mediated molecular delivery to breast cancer in an animal model.

Tumors become inoperable due to their size or location, making neoadjuvant chemotherapy the primary treatment. However, target tissue accumulation of anticancer agents is limited by the physical barriers of the tumor microenvironment. Low-intensity focused ultrasound (FUS) in combination with microbubble (MB) contrast agents can increase microvascular permeability and improve drug delivery to the target tissue after systemic administration.

Simultaneous imaging of ultrasonic relative backscatter and attenuation coefficients for quantitative liver steatosis assessment.

Prevalence of liver disease is continuously increasing and nonalcoholic fatty liver disease (NAFLD) is the most common etiology. We present an approach to detect the progression of liver steatosis based on quantitative ultrasound (QUS) imaging. This study was performed on a group of 55 rats that were subjected to a control or methionine and choline deficient (MCD) diet known to induce NAFLD.

Photoacoustic graphic equalization and application in characterization of red blood cell aggregates.

A photoacoustic (PA) graphic equalization (PAGE) algorithm was developed to characterize the relative size of optical absorbing aggregates. This technique divides the PA signal into frequency bands related to different-sized optical absorbers. Simulations of a material containing optical absorbing microparticles of varying size were used to assess PAGE performance.

Disease-Specific Imaging Utilizing Support Vector Machine Classification of H-Scan Parameters: Assessment of Steatosis in a Rat Model.

In medical imaging, quantitative measurements have shown promise in identifying diseases by classifying normal versus pathological parameters from tissues. The support vector machine (SVM) has shown promise as a supervised classification algorithm and has been widely used. However, the classification results typically identify a category of abnormal tissues but do not necessarily differentiate progressive stages of a disease.

Intercellular Arc Signaling Regulates Vasodilation.

Injury responses require communication between different cell types in the skin. Sensory neurons contribute to inflammation and can secrete signaling molecules that affect non-neuronal cells. Despite the pervasive role of translational regulation in nociception, the contribution of activity-dependent protein synthesis to inflammation is not well understood.

Multiparametric ultrasound imaging for the assessment of normal versus steatotic livers.

Liver disease is increasing in prevalence across the globe. We present here a multiparametric ultrasound (mpUS) imaging approach for assessing nonalcoholic fatty liver disease (NALFD). This study was performed using rats (N = 21) that were fed either a control or methionine and choline deficient (MCD) diet.

Multifocused Ultrasound Therapy for Controlled Microvascular Permeabilization and Improved Drug Delivery.

Focused ultrasound (FUS) exposure of micro-bubble (MB) contrast agents can transiently increase microvascular permeability allowing anticancer drugs to extravasate into a targeted tumor tissue. Either fixed or mechanically steered in space, most studies to date have used a single element focused transducer to deliver the ultrasound (US) energy. The goal of this study was to investigate various multi-FUS strategies implemented on a programmable US scanner (Vantage 256, Verasonics Inc.

Understanding the Contrast Mechanism in Rotation Elastogram: A Parametric Study.

Ultrasound elastography has been found to be useful in different clinical applications. For example, in breast imaging, axial strain elastography provides information related to tissue stiffness, which is used to characterize breast lesions as either benign or malignant. In addition, these lesions also differ in their bonding properties.