Automated Force-Coupled Ultrasound Method for Calibration-Free Carotid Artery Blood Pressure Estimation.

We develop, automate and evaluate a calibration-free technique to estimate human carotid artery blood pressure from force-coupled ultrasound images. After acquiring images and force, we use peak detection to align the raw force signal with an optical flow signal derived from the images. A trained convolutional neural network selects a seed point within the carotid in a single image.

Variation of Shear Wave Elastography With Preload in the Thyroid: Quantitative Validation.

Objectives: Thyroid shear wave elastography (SWE) has been shown to have advantages compared to biopsy or other imaging modalities in the evaluation of thyroid nodules. However, studies show variability in its assessment. The objective of this study was to evaluate whether stiffness measurements of the normal thyroid, as estimated by SWE, varied due to preload force or the pressure applied between the transducer and the patient.

Experimental Validation of Longitudinal Speed of Sound Estimates in the Diagnosis of Hepatic Steatosis (Part II).

This study validates a non-invasive, quantitative technique to diagnose steatosis within tissue. The proposed method is based on two fundamental concepts: (i) the speed of sound in a fatty liver is lower than that in a healthy liver and (ii) the quality of an ultrasound image is maximized when the beamformer's speed of sound matches the speed in the medium under examination. The method uses image brightness and sharpness as quantitative image-quality metrics to predict the true sound speed and capture the effects of fat infiltration, while accounting for the transmission through subcutaneous fat.

Quantitative Hepatic Fat Quantification in Non-alcoholic Fatty Liver Disease Using Ultrasound-Based Techniques: A Review of Literature and Their Diagnostic Performance.

Non-alcoholic fatty liver disease is a condition that is characterized by the presence of >5% fat in the liver and affects more than one billion people worldwide. If adequate and early precautions are not taken, non-alcoholic fatty liver disease can progress to cirrhosis and death. The current reference standard for detecting hepatic steatosis is a liver biopsy.

Surgery for Obesity and Related Diseases: I. A Novel Approach to the Quantification of the Longitudinal Speed of Sound and Its Potential for Tissue Characterization.

Described here is a method to determine the longitudinal speed of sound in speckle-dominated ultrasound images. The method is based on the concept that the quality of an ultrasound image is maximized when the beamformer's speed of sound matches the speed in the medium. The method captures the quality of the ultrasound image using two quantitative image-quality metrics: image brightness and sharpness around the intended focal zone.

High-throughput particle separation and concentration using spiral inertial filtration.

A spiral inertial filtration (SIFT) device that is capable of high-throughput (1 ml/min), high-purity particle separation while concentrating recovered target particles by more than an order of magnitude is reported. This device is able to remove large fractions of sample fluid from a microchannel without disruption of concentrated particle streams by taking advantage of particle focusing in inertial spiral microfluidics, which is achieved by balancing inertial lift forces and Dean drag forces. To enable the calculation of channel geometries in the SIFT microsystem for specific concentration factors, an equivalent circuit model was developed and experimentally validated.

Enrichment of tumor-initiating breast cancer cells within a mammosphere-culture microdevice.

We report for the first time a microdevice that enables the selective enrichment, culture, and identification of tumor-initiating cells on native polydimethylsiloxane (PDMS). For nearly a decade, researchers have identified tumor-initiating breast cancer cells within heterogeneous populations of breast cancer cells by utilizing low-attachment serum-free culture conditions, which lead to the formation of spheroidal colonies (mammospheres) that are enriched for tumor-initiating cells. However, the utility of this assay has been limited by difficulties in combining this culture-plate-based technique with other cellular and molecular analyses.