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Leukemia commonly leads to hypoxia in the bone marrow, which can then result in increased resistance to chemotherapy. However, the relationship between local hypoxia and disease progression is not well understood, and it is unclear whether hypoxia in the bone marrow is diffuse or focal in presentation. Spectroscopic photoacoustic (PA) imaging-based estimation of blood oxygen saturation (SO2) can be...
Spontaneous preterm birth, the foremost source of neonatal mortality, could potentially be prevented by objectively detecting abnormal changes in the uterine cervix. Shear Wave Elasticity Imaging (SWEI) biomarkers can quantify cervical softening that precedes vaginal delivery. This task can be complicated by biological (i.e., heterogeneity of cervical stiffness and pregnancy history) and experimental...
It is critical to use a proper spatial sampling, otherwise images suffer from grating lobes. However, the cost of a medical ultrasound scanner is strongly related to the channel count of the receive electronics. This has led to channel reduction using multiplexing or in-probe pre-beamforming methods at the cost of image quality or frame rate. An alternative is to reduce the receive channel count and...
Carotid plaque rupture is a primary cause of ischemic strokes and transient ischemic attacks (TIAs). Probability of stroke and TIAs depend on the mechanical stability of plaque. Ultrasound strain can provide a non-invasive assessment of plaque stiffness to assess mechanical stability. We report on ultrasound strain indices from multiple regions of interest (ROI) in plaque as biomarkers for plaque...
As the medical ultrasound signals are not stationary, the radiation pattern of the corresponding input data does not have a specific shape. Thus, their reconstruction using adaptive beamformer (BF) become indispensable in order to improve the quality of the image. Generalized Side Lobe Canceller (GSC) is a robust realization against clutter and interference, resulting from an elegant representation...
Medical imaging through a targeting agent promises to improve the specificity and sensitivity of cancer detection. Nanoparticles (NPs) may provide advantages for targeted photoacoustic (PA) imaging due to their unique physical and optical properties. In our previous study, we developed a phase-change contrast agent made from a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA) and loaded...
Cardiovascular diseases are the leading cause of death globally. Such diseases may affect the left ventricular function, which in turn is closely related to the left ventricular stiffness. Estimation of cardiac deformation can give information on the myocardial stiffness, and may therefore be important in assessment of cardiovascular diseases. A 3D motion estimation scheme is necessary to measure...
High-frequency ultrasound (>20 MHz) imaging has gained widespread attention due to its high spatial resolution being useful for basic cardiovascular and cancer research involving small animals. The sampling rate of the analog-to-digital converter in a high-frequency ultrasound system usually needs to be higher than 120-MHz to satisfy the Nyquist requirement. However, the sampling rate is typically...
Keloids are benign dermal disease that are characterized by the collagen deposition and growth beyond the boundaries of the original wound position. Many studies on keloids have showed that the density of blood vessel within keloids is higher than normal skin, which is a determinant of the physiological conditions of the tissue and also important for understanding the pathogenesis and radiotherapy...
Currently there are two main categories of adaptive beamforming applied to medical ultrasound imaging: minimum-variance-related beamforming(MV) and coherence-factor-related beamforming (CF), both of which have been applied to suppress side/granting lobe and clutter for plane-wave imaging. Unfortunately, due to low SNR/SINR, the resulting images may suffer from deficiencies: deteriorated speckle pattern,...
Super-resolution (SR) ultrasound enables detailed assessment of the fine vascular network by pinpointing individual microbubbles (MBs), using ultrasound contrast agents (UCAs). The information in SR images is determined by the density of localized MBs and their localization accuracy. To obtain high densities, one can evaluate extremely sparse subsets of MBs across thousands of frames by using a very...
ARFI displacements have been shown to share an inverse relationship with shear wave speed — based estimates of tissue elasticity. Both ARFI and shear wave elasticity imaging (SWEI) have been used to track the stiffening and softening of myocardium through the cardiac cycle in open-chest, intracardiac, and Langendorff preparations. In transthoracic imaging, induced shear waves have been observed during...
It is crucial to transport foreign substance into living cells efficiently and minimize adverse side-effects. Using ultrasound microbubble, it is possible to enhance the cellular uptake and transfer the extracellular molecules into cells, this process is called sonoporation. However, the spatial location of microbubbles appears to be a stochastic process, which makes the targeted sonoporation at specific...
To acquire reliable medical ultrasound images and accurately detect vascular diseases, it is inevitable to improve axial resolution and contrast facilitating clearly definition of depth and thickness of blood vessel walls.
The design of 3D TEE transducers poses severe technical challenges: channel count, electronics integration with high and low voltages, heat dissipation, etc. We present an adult matrix TEE probe with separate transmit (Tx) and receive (Rx) arrays allowing optimization in both Tx and Rx [1]. Tx elements are directly wired out, Rx employs integrated micro-beamformers in low-voltage (1.8/5.0V) chip technology...
Transient blood-brain barrier (BBB) opening via focused ultrasound (FUS) combined with intravenously circulating microbubbles (MBs) may have a role in the treatment of Alzheimer's disease (AD). Spectral characteristics of MB emissions recorded during the procedures using single-element detectors have correlated with biological outcomes [McDannold et al. PMB 2006], leading to the development of acoustic...
In the last 10 years the advent of high frame rate ultrasound imaging has allowed the visualization and study of mechanical wave propagation in order to estimate the elastic properties of tissue. Theses waves are detected through the estimation of motion induced by the wave propagation. Despite efficient motion estimator such as speckle tracking or Tissue Doppler Imaging (TDI), the detection of mechanical...
The focused ultrasound (FUS) systems are widely used due to their ability to generate a tight and intense focal region from a distributed source for the non-invasive and safely detection. However, these devices usually require elaborate arrays of a rather complex and cumbersome set of transducers. Holographic techniques are fundamental to applications such as volumetric displays and tweezers. The...
Recently a new beamformer called the Delay-Multiply-And-Sum (DMAS) beamformer was introduced in the field of medical ultrasound imaging (Matrone et al IEEE Trans. Med. Imag. 2015). Instead of summing the signals recorded by each transducer element as with the Delay-And-Sum (DAS) beamformer, the DMAS algorithm multiplies the signals pairwise before summing them. This multiplication creates an “artificial...
Early detection and diagnosis of high-risk vulnerable plaques can reduce the death rate attributable to atherosclerosis. Many attempts to identify plaques have focused on in vivo imaging techniques. Animal models with foregone plaque sites will be valuable to evaluate the validity of the imaging methods. However, in traditional balloon injury models, the sites and size of generated plaques are uncertain...
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