Comparison of Phase-Screen and Geometry-Based Phase Aberration Correction Techniques for Real-Time Transcranial Ultrasound Imaging

While transcranial ultrasound imaging is a promising diagnostic modality, it is still hindered due to phase aberration and multiple scattering caused by the skull. In this paper, we compare near-field phase-screen modeling (PS) to a geometry-based phase aberration correction technique (GB) when an ultrafast imaging sequence (five plane waves...

Multi-angle data acquisition to compensate transducer finite size in photoacoustic tomography

In photoacoustic tomography (PAT) systems, the tangential resolution decreases due to the finite size of the transducer as the off-center distance increases. To address this problem, we propose a multi-angle detection approach in which the transducer used for data acquisition rotates around its center (with specific angles) as well as around...

Accelerated 2D Real-Time Refraction-Corrected Transcranial Ultrasound Imaging

In a recent study, we proposed a technique to correct aberration caused by the skull and reconstruct a transcranial B-mode image with a refraction-corrected synthetic aperture imaging (SAI) scheme. Given a sound speed map, the arrival times were calculated using a fast marching technique (FMT), which solves the Eikonal equation and, therefore...

Refraction-Corrected Transcranial Ultrasound Imaging through the Human Temporal Window using a Single Probe

Transcranial ultrasound imaging (TUI) is a diagnostic modality with numerous applications, but unfortunately, it is hindered by phase aberration caused by the skull. In this article, we propose to reconstruct a transcranial B-mode image with a refraction-corrected synthetic aperture imaging (SAI) scheme. First, the compressional sound...

Numerical Investigation of Multiple Scattering and Mode-Converted Shear Waves Caused by Temporal Bone in Transcranial Photoacoustic Imaging

In recent years, transcranial photoacoustic (TPA) imaging has become a popular modality for diagnosis of brain disorders. However, due to the presence of skull, TPA images are strongly degraded. Acoustically, this degradation is mainly categorized into the phase aberration, mode-converted shear waves, and multiple scattering. Previous studies...

A Tiled Ultrasound Matrix Transducer for Volumetric Imaging of the Carotid Artery

High frame rate three-dimensional (3D) ultrasound imaging would offer excellent possibilities for the accurate assessment of carotid artery diseases. This calls for a matrix transducer with a large aperture and a vast number of elements. Such a matrix transducer should be interfaced with an application-specific integrated circuit (ASIC) for...

Motion-compensated noninvasive periodontal health monitoring using handheld and motor-based photoacoustic-ultrasound imaging systems

Simultaneous visualization of the teeth and periodontium is of significant clinical interest for image-based monitoring of periodontal health. We recently reported the application of a dual-modality photoacoustic-ultrasound (PA-US) imaging system for resolving periodontal anatomy and periodontal pocket depths in humans. This work utilized a...

Finite Transducer Size Compensation in Two-Dimensional Photoacoustic Computed Tomography

In circular photoacoustic computed tomography, for data acquisition, a single-element transducer rotates around the region of interest (ROI). Due to the limited acceptance angle of the finite size transducer, the reconstructed image becomes blurred, and tangential resolution/contrast degrades in off-center locations in the ROI. In this paper, we...

Transcranial Ultrasound Imaging with Estimating the Geometry, Position and Wave-Speed of Temporal Bone

Transcranial ultrasound imaging is a suitable technology for diagnosis of strokes as it is safe, portable, relatively inexpensive and available in emergency medicine services, however it currently offers poor image quality due to the phase aberration caused by the human skull. In this work, we evaluate an approach for two-dimensional...

Erratum: Lamb Waves and Adaptive Beamforming for Aberration Correction in Medical Ultrasound Imaging: Lamb Waves and Adaptive Beamforming for Aberration Correction in Medical Ultrasound Imaging (IEEE Trans.Ultrason., Ferroelectr., Freq. Control, early access (2020) DOI: 10.1109/TUFFC.2020.3007345)

In the above article [1], we mentioned that the superposition of the different symmetric (S) modes in the frequencywavenumber (f-k) domain results in a high-intensity region where its slope corresponds to the longitudinal wave speed in the slab. However, we have recently understood that this highintensity region belongs to the propagation of...

Lamb Waves and Adaptive Beamforming for Aberration Correction in Medical Ultrasound Imaging

Phase aberration in transcranial ultrasound imaging (TUI) caused by the human skull leads to an inaccurate image reconstruction. In this article, we present a novel method for estimating the speed of sound and an adaptive beamforming technique for phase aberration correction in a flat polyvinylchloride (PVC) slab as a model for the human...

Receive/transmit aperture selection for 3D ultrasound imaging with a 2D matrix transducer

Recently, we realized a prototype matrix transducer consisting of 48 rows of 80 elements on top of a tiled set of Application Specific Integrated Circuits (ASICs) implementing a row-level control connecting one transmit/receive channel to an arbitrary subset of elements per row. A fully sampled array data acquisition is implemented by a...

Fabrication and Characterization of a Prototype Forward-Looking Single-Cable 64-Element Intra-Vascular Ultrasound Probe

This paper presents the integration steps towards a prototype forward-looking intra-vascular ultrasound probe. An ASIC (Application Specific Integrated Circuit) is laser cut to create a 1.6mm circular shaped die that can be integrated at the tip of a small catheter. The ASIC is designed such that it can be used to transmit and receive on 64...

Development of a stationary 3D photoacoustic imaging system using sparse single-element transducers: Phantom study

Photoacoustic imaging (PAI) is an emerging label-free and non-invasive modality for imaging biological tissues. PAI has been implemented in different configurations, one of which is photoacoustic computed tomography (PACT) with a potential wide range of applications, including brain and breast imaging. Hemispherical Array PACT (HA-PACT) is a...

3D high frame rate flow measurement using a prototype matrix transducer for carotid imaging

To accurately investigate the state of the carotid artery by the local haemodynamics and motion of the plaque using ultrasound, high-frame rate volumetric imaging is necessary. We have specifically designed a matrix array for this purpose. In this proceeding we will focus on imaging a volumetric flow profile using this matrix. For this...

Enhanced contrast acoustic-resolution photoacoustic microscopy using double-stage delay-multiply-and-sum beamformer for vasculature imaging

In acoustic-resolution photoacoustic microscopy (AR-PAM) systems, the lateral resolution in the focal zone of the ultrasound (US) transducer is determined by the numerical aperture (NA) of the transducer. To have a high lateral resolution, a large NA is used. However, the larger the NA, the smaller the depth of focus [DOF]. As a result, the...