Transcranial ultrasound localization microscopy of the rat brain with ray theory-based aberration correction.

Transcranial ultrasound localization microscopy (t-ULM) is faced with challenges posed by the skull, including acoustic attenuation and phase aberrations. There is a significant request for an efficient aberration correction method achieving a great balance between computational complexity and accuracy. In this study, the ray theory is first applied to in-vivo transcranial imaging to calculate the traveltime table in the inhomogeneous medium model of the imaging region.

Real-Time 3-D Passive Acoustic Mapping for Row-Column Arrays With the Cross-Spectrum Method.

Real-time and 3-D monitoring of cavitation activity is critical for safe, effective, and controlled treatments in cavitation-based focused ultrasound (FUS) therapies. This 3-D monitoring capability is essential for detecting off-target cavitation events, particularly in at-risk structures and those occurring outside the plane of 2-D imaging. In this work, we demonstrate that using row-column arrays (RCAs) for 3-D passive acoustic mapping (PAM), which can be easily integrated into commercial ultrasound scanners compared to using hemispherical arrays or matrix arrays, represents a potent solution.

Interaction between post-tumor inflammation and vascular smooth muscle cell dysfunction in sepsis-induced cardiomyopathy.

Background: Sepsis-induced cardiomyopathy (SIC) presents a critical complication in cancer patients, contributing notably to heart failure and elevated mortality rates. While its clinical relevance is well-documented, the intricate molecular mechanisms that link sepsis, tumor-driven inflammation, and cardiac dysfunction remain inadequately explored. This study aims to elucidate the interaction between post-tumor inflammation, intratumor heterogeneity, and the dysfunction of VSMC in SIC, as well as to evaluate the therapeutic potential of exercise training and specific pharmacological interventions.

Single-Crystal Row-Column Array-Based Rat Brain 3-D Ultrasound Localization Microscopy.

Ultrasound localization microscopy (ULM) enables imaging of cerebral vasculature at a microscopic scale with deep penetration. However, conventional 2-D ULM suffers from elevation projection and cannot capture the out-of-plane vessels. Recently developed volumetric ULM overcomes the limitations by providing isotropic resolution and enabling comprehensive visualization of the microvascular architecture in three dimensions.

Vortex-encoded full-waveform inversion-based ultrasound computed tomography.

Ultrasound imaging of musculoskeletal tissue has long been a challenge. As a novel medical ultrasound computed tomography (UCT) technique, full-waveform inversion (FWI) provides a promising solution for musculoskeletal imaging with high spatial resolution. However, FWI suffers from a substantial computational burden, primarily due to the multiple wavefield calculations involved in the inversion process, especially when dealing with a large number of sources.

4-D Vector Doppler Imaging Using Row-Column Addressed Array.

Large aperture 4-D blood flow Doppler imaging with high temporal resolution remains an important challenge. Different from the conventional matrix-array strategy, we proposed a 4-D ultrasound vector Doppler (4D-UVD) imaging method using a $128+128$ row-column addressed (RCA) array and a 256-channel ultrasound platform. This method integrates ultrafast 2-D plane wave transmission sequence and least-squares multiangle Doppler velocity estimator.

Quantitative analysis of variation in photoacoustic guided wave characteristics with bone optical properties.

Tissue optical and mechanical properties are key indicators of bone health, and influence the generation and propagation of photoacoustic guided waves (PAGWs). The effectiveness of mechanical property characterization based on mode dispersion features of ultrasonic guided waves has been demonstrated in the diagnosis of osteoporosis; however, variation in PAGW characteristics with bone optical properties is less analyzed. It limits the development of ultrasound in precision diagnosis of bone diseases.

Functional Ultrasound Imaging of Cocaine Induced Brain-Wide Neurovascular Response.

Extensive studies have reported that cocaine can lead to potent reduction in cerebral blood flow. However, the mechanisms of the cocaine's impact on the neural and vascular system of brain in temporal and spatial aspects remain elusive. Functional ultrasound (fUS) is a novel neurovascular imaging modality acclaimed for its deep penetration, superior spatiotemporal resolution, and high sensitivity to small blood flow dynamics.

A fiber-shaped ultrasonic transducer by designing a flexible epoxy/nano-zirconia composite as an acoustic matching layer.

Acoustic matching layers play an important role in ultrasonic transducers. However, the acoustic matching layer with both intrinsic flexibility and high acoustic impedance remains an unmet need to achieve high-performing flexible ultrasonic transducers. Herein, we present an epoxy/nano-zirconia composite with excellent flexibility and acoustic performance by the chemical coupling method.

Ultrasonic detection of wrinkles in composites with gradual phase shift migration.

Fiber reinforced polymer composites (FRPs) are essential for various industrial fields, but wrinkles inside will greatly reduce their mechanical properties. Full-matrix capture (FMC) is a popular data structure for ultrasonic phased array imaging in composites. However, such structure may lead to data redundancy and noise interference.

Transcranial ultrafast ultrasound Doppler imaging: A phantom study.

Ultrafast ultrasound Doppler imaging facilitates the assessment of cerebral hemodynamics with high spatio-temporal resolution. However, the significant acoustic impedance mismatch between the skull and soft tissue results in phase aberrations, which can compromise the quality of transcranial imaging and introduce biases in velocity and direction quantification of blood flow. This paper proposed an aberration correction method that combines deep learning-based skull sound speed modelling with ray theory to realize transcranial plane-wave imaging and ultrafast Doppler imaging.

Nonlinear simulation for contrast ultrasound imaging.

Contrast ultrasound (CUS) has received much interest because of its sensitivity enhancement for blood flow imaging. However, there is still a lack of nonlinear simulation method for CUS, as conventional simulators cannot deal with the microbubble acoustic nonlinearity. In this paper, a nonlinear simulation method of CUS is developed based on a combination strategy of the k-space pseudospectral method and Rayleigh-Plesset Marmottant model.

Unsupervised Learning-Based Measurement of Ultrasonic Axial Transmission Velocity in Neonatal Bone.

Objectives: To develop a robust algorithm for estimating ultrasonic axial transmission velocity from neonatal tibial bone, and to investigate the relationships between ultrasound velocity and neonatal anthropometric measurements as well as clinical biochemical markers of skeletal health.

Methods: This study presents an unsupervised learning approach for the automatic detection of first arrival time and estimation of ultrasonic velocity from axial transmission waveforms, which potentially indicates bone quality. The proposed method combines the ReliefF algorithm and fuzzy C-means clustering.

Association between musculoskeletal pain and exposures to awkward postures during work: a compositional analysis approach.

Objectives: This study aimed to explore the association between arm elevation and neck/shoulder pain, and trunk forwarding bending and low back pain among home care workers.

Methods: Home care workers (N = 116) from 11 home care units in Trondheim, Norway, filled in pain assessment and working hours questionnaire, and wore 3 accelerometers for up to 7 consecutive days. Work time was partitioned into upright awkward posture, nonawkward posture, and nonupright time, i.

Transcriptomic effects of paternal cocaine-seeking on the reward circuitry of male offspring.

It has been previously established that paternal development of a strong incentive motivation for cocaine can predispose offspring to develop high cocaine-seeking behavior, as opposed to sole exposure to the drug that results in drug resistance in offspring. However, the adaptive changes of the reward circuitry have not been fully elucidated. To infer the key nuclei and possible hub genes that determine susceptibility to addiction in offspring, rats were randomly assigned to three groups, cocaine self-administration (CSA), yoked administration (Yoke), and saline self-administration (SSA), and used to generate F1.

Allicin protects against LPS-induced cardiomyocyte injury by activating Nrf2-HO-1 and inhibiting NLRP3 pathways.

Background: Allicin is a bioactive compound with potent antioxidative activity and plays a protective effect in myocardial damage and fibrosis. The role and mechanism of Allicin in septic cardiomyopathy are unclear. In this study, we investigated the effects and underlying mechanisms of Allicin on lipopolysaccharide (LPS) induced injury in H9c2 cardiomyocytes.

Ray theory-based compounded plane wave ultrasound imaging for aberration corrected transcranial imaging: Phantom experiments and simulations.

Compounded plane wave imaging (CPWI) allows high-frame-rate measurement and has been one of the most promising modalities for real-time brain imaging. However, ultrasonic brain imaging using the CPWI modality is usually performed with a worn thin or removal of the skull layer. Otherwise, the skull layer is expected to distort the ultrasonic wavefronts and significantly decrease intracranial imaging quality.

Super-resolution Ultrasound Microvascular Angiography for Spinal Cord Penumbra Imaging.

Objective: After spinal cord injury (SCI) or ischemia, timely intervention in the penumbra, such as recanalization and tissue reperfusion, is essential for preservation of its function. However, limited by imaging resolution and micro-blood flow sensitivity, golden standard angiography modalities, including magnetic resonance angiography (MRA) and digital subtraction angiography (DSA), are still not applicable for spinal cord microvascular imaging. Regarding spinal cord penumbra, to the best of authors' knowledge, currently, there is no efficient in vivo imaging modality for its evaluation.

Frequency-domain full-waveform inversion-based musculoskeletal ultrasound computed tomography.

Recently, full-waveform inversion (FWI) has become a promising tool for ultrasound computed tomography (USCT). However, as a computationally intensive technique, FWI suffers from computational burden, especially in conventional time-domain full-waveform inversion (TDFWI). On the contrary, frequency-domain full-waveform inversion (FDFWI) provides a relatively high computational efficiency as the propagation of discrete frequencies is much cheaper than full time-domain modeling.

Ultrafast Doppler Imaging of Brain Arteriovenous Malformation.

Ultrafast ultrasound Doppler imaging offers a new and advantageous intraoperative method for brain lesions. Compared to the conventional color Doppler ultrasound system, the ultrafast Doppler allows us to image hemodynamics in small vasculature in an unprecedented high spatio-temporal resolution without using contrast agent. This report presents an intraoperative ultrafast ultrasound Doppler image of a 53-year-old male with a language eloquent area brain arteriovenous malformation.

Ultrafast Ultrasound Vector Doppler for Small Vasculature Imaging.

Ultrafast Doppler has been accepted as a novel modality for small vasculature imaging with high sensitivity, high spatiotemporal resolution, and high penetration. However, the conventional Doppler estimator adopted in studies of ultrafast ultrasound imaging is only sensitive to the velocity component along the beam direction and has angle-dependent limitations. Vector Doppler has been developed with the goal of angle-independent velocity estimation but is typically employed for relatively large vessels.

A Bayesian Filtering Approach to Multimode Separation and Retrieval of Ultrasonic Guided Waves.

In this article, a Bayesian filtering approach to adaptively extracting the crossed time-frequency (TF) ridges of ultrasonic guided waves (GWs) and retrieving their overlapped modes is proposed. Based on the generalized non-parametric GW signal model, the phase evolution of each overlapped mode can be described by the state transition equation developed by a polynomial prediction model (PPM). When an analyzed GW in the frequency domain is viewed as the measurement equation of the states, a state space model in the frequency domain for describing the GW and its modes is established.

Frame rate effects and their compensation on super-resolution microvessel imaging using ultrasound localization microscopy.

Ultrasound localization microscopy (ULM) breaks the diffraction limit and allows imaging microvasculature at micrometric resolution while preserving the penetration depth. Frame rate plays an important role for high-quality ULM imaging, but there is still a lack of review and investigation of the frame rate effects on ULM. This work aims to clarify how frame rate influences the performance of ULM, including the effects of microbubble detection, localization and tracking.