Ultrasonic viscoelasticity imaging of nonpalpable breast tumors: preliminary results.

Rationale And Objectives: Improvements in the diagnosis of early breast cancers depend on a physician's ability to obtain the information necessary to distinguish nonpalpable malignant and benign tumors. Viscoelastic features that describe mechanical properties of tissues may help to distinguish these types of lesions.

Materials And Methods: Twenty-one patients with nonpalpable, pathology-confirmed Breast Imaging Reporting and Data System (BIRADS) 4 or 5 breast lesions (10 benign, 11 malignant) detected by mammography were studied.

Spatial regulation of inflammation by human aortic endothelial cells in a linear gradient of shear stress.

Objective: Atherosclerosis is a focal disease that develops at sites of low and oscillatory shear stress in arteries. This study aimed to understand how endothelial cells sense a gradient of fluid shear stress and transduce signals that regulate membrane expression of cell adhesion molecules and monocyte recruitment.

Methods: Human aortic endothelial cells were stimulated with TNF-alpha and simultaneously exposed to a linear gradient of shear stress that increased from 0 to 16 dyne/cm2.

Role of ultrasonic shear rate estimation errors in assessing inflammatory response and vascular risk.

Atherosclerotic lesions preferentially originate in arterial regions that experience low wall shear stress (WSS) and reversing flow patterns. Therefore, routinely monitoring arterial WSS may help to identify the potential sites of early atherosclerosis. A new noninvasive ultrasonic method implemented with coded excitation techniques was utilized to improve WSS estimation accuracy and precision by providing high spatial and temporal resolution.

Modeling and phantom studies of ultrasonic wall shear rate measurements using coded pulse excitation.

Wall shear rate (WSR) is the derivative of blood velocity with respect to vessel radius at the endothelial cell (EC) surface. The product of WSR and blood viscosity is the wall shear stress (WSS) that has been identified as an important factor for atherosclerosis development. High echo signal-to-noise ratio (eSNR) and high spatial resolution are crucial for minimizing the errors in WSR estimates.