Color Flow Ultrasound Spatial Sampling Beam Density for Partial Volume-Corrected Three-Dimensional Volume Flow (3DVF): Theory, Simulation, and Experiment.

Objective: The purpose of this study was to quantify the accuracy of partial volume-corrected three-dimensional volume flow (3DVF) measurements as a function of spatial sampling beam density using carefully-designed parametric analyses in order to inform the target applications of 3DVF.

Methods: Experimental investigations employed a mechanically-swept curvilinear ultrasound array to acquire 3D color flow (6.3 MHz) images in flow phantoms consisting of four lumen diameters (6.

Volumetric blood flow in transjugular intrahepatic portosystemic shunt revision using 3-dimensional Doppler sonography.

Objectives: Three-dimensional (3D)/4-dimensional (4D) sonographic measurement of blood volume flow in transjugular intrahepatic porto systemic shunt revision with the intention of objective assessment of shunt patency.

Methods: A total of 17 patients were recruited (12 male and 5 female; mean age, 55 years; range, 30-69 years). An ultrasound system equipped with a 2.

Three-dimensional sonographic measurement of blood volume flow in the umbilical cord.

Objectives: Three-dimensional (3D) umbilical cord blood volume flow measurement with the intention of providing a straightforward, consistent, and accurate method that overcomes the limitations associated with traditional pulsed wave Doppler flow measurement and provides a means by which to recognize and manage at-risk pregnancies.

Methods: The first study involved 3D sonographic volume flow measurements in 7 healthy ewes whose pregnancies ranged from 18 to 19 weeks' gestation (7 singletons). Sonographic umbilical arterial and venous flow measurements from each fetus were compared to the corresponding average measured arterial/venous flow to assess the feasibility of measurement in a static vessel.

Subharmonic contrast microbubble signals for noninvasive pressure estimation under static and dynamic flow conditions.

Our group has proposed the concept of subharmonic aided pressure estimation (SHAPE) utilizing microbubble-based ultrasound contrast agent signals for the noninvasive estimation of hydrostatic blood pressures. An experimental system for in vitro SHAPE was constructed based on two single-element transducers assembled confocally at a 60 degree angle to each other. Changes in the first, second and subharmonic amplitudes of five different ultrasound contrast agents were measured in vitro at static hydrostatic pressures from 0-186 mmHg, acoustic pressures from 0.

Real-time co-registration using novel ultrasound technology: ex vivo validation and in vivo applications.

Objective: The study objective was to evaluate whether a novel global position system (GPS)-like position-sensing technology will enable accurate co-registration of images between imaging modalities. Co-registration of images obtained by different imaging modalities will allow for comparison and fusion between imaging modalities, and therefore has significant clinical and research implications. We compared ultrasound (US) and magnetic resonance imaging (MRI) scans of carotid endarterectomy (CEA) specimens using a novel position-sensing technology that uses an electromagnetic (EM) transmitter and sensors mounted on a US transducer.

Parametric imaging using subharmonic signals from ultrasound contrast agents in patients with breast lesions.

Parametric maps showing perfusion of contrast media can be useful tools for characterizing lesions in breast tissue. In this study we show the feasibility of parametric subharmonic imaging (SHI), which allows imaging of a vascular marker (the ultrasound contrast agent) while providing near complete tissue suppression. Digital SHI clips of 16 breast lesions from 14 women were acquired.

Static and dynamic cumulative maximum intensity display mode for subharmonic breast imaging: a comparative study with mammographic and conventional ultrasound techniques.

Objective: The purpose of this study was to test the efficacy of static and dynamic cumulative maximum intensity (CMI) subharmonic imaging (SHI) in breast ultrasound studies.

Methods: Contrast-enhanced SHI was performed in 14 women using a modified LOGIQ 9 scanner (GE Healthcare, Milwaukee, WI) transmitting/receiving at 4.4/2.

Mean volume flow estimation in pulsatile flow conditions.

To verify a previously reported three-dimensional (3D) ultrasound method for the measurement of time-average volumetric blood flow, experiments were performed under pulsatile flow conditions, including in vivo investigations, and results were compared with accepted, but invasive, "gold standard" techniques. Results showed that volume averaging results in the correct time-average volume flow without the need for cardiac gating. Unlike other currently employed methods, this method is independent of Doppler angle, flow profile and vessel geometry.

Characterization of cysts using differential correlation coefficient values from two dimensional breast elastography: preliminary study.

Although simple cysts are easily identified using sonography, description and management of nonsimple cysts remains uncertain. This study evaluated whether the correlation coefficient differences between breast tissue and lesions, obtained from 2D breast elastography, could potentially distinguish nonsimple cysts from cancers and fibroadenomas. We hypothesized that correlation coefficients in cysts would be dramatically lower than surrounding tissue because noise, imaging artifacts, and particulate matter move randomly and decorrelate quickly under compression, compared with solid tissue.

Breast lesions: imaging with contrast-enhanced subharmonic US--initial experience.

Purpose: To prospectively compare accuracy of gray-scale subharmonic imaging (SHI) with that of standard gray-scale ultrasonography (US), power Doppler US (with and without contrast material), and mammography for the diagnosis of breast cancer, with histopathologic or clinical follow-up results as the reference standard.

Materials And Methods: This HIPAA-compliant pilot study had institutional review board approval; all subjects gave written informed consent. Fourteen women (age range, 37-66 years) had 16 biopsy-proved breast lesions.

Measurement of volumetric flow.

Objective: The purpose of this study was to evaluate a 3-dimensional (3D) sonographic method for the measurement of volumetric flow under conditions of known flow rates and Doppler angles.

Methods: A GE/Kretz Voluson 730 system (GE Healthcare, Milwaukee, WI) and RAB2-5 probe were used to acquire 3D Doppler measurements in a custom flow phantom. Blood-mimicking fluid circulated by a computer-controlled pump provided a range of flow velocities (2-15 mL/s).

Vector Doppler imaging of a spinning disc ultrasound Doppler phantom.

Vector Doppler methods are used to obtain angle independent in-plane velocity information. Velocity magnitude as well as direction are reconstructed from regular steered colour flow and from split-aperture Doppler acquisitions. Spatially resolved in-plane velocity was obtained through Doppler colour flow mode and subsequent data triangulation.

In vivo perfusion estimation using subharmonic contrast microbubble signals.

Objective: The purpose of this study was to quantify perfusion in vivo using contrast-enhanced subharmonic imaging (SHI).

Methods: A modified LOGIQ 9 scanner (GE Healthcare, Milwaukee, WI) operating in gray scale SHI mode was used to measure SHI time-intensity curves in vivo. Four dogs received intravenous contrast bolus injections (dose, 0.

Real-time excitation-enhanced ultrasound contrast imaging.

A new nonlinear contrast specific imaging modality, excitation-enhanced imaging (EEI) has been implemented on commercially-available scanners for real-time imaging. This novel technique employs two acoustic fields: a low-frequency, high-intensity ultrasound field (the excitation field) to actively condition contrast microbubbles, and a second lower-intensity regular imaging field applied shortly afterwards to detect enhanced contrast scattering. A Logiq 9 scanner (GE Healthcare, Milwaukee, WI) with a 3.