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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...
Microembolization during PCI for acute myocardial infarction can cause microvascular obstruction (MVO). MVO severely limits the success of reperfusion therapies and is linked to worse prognosis, including death. A recent clinical trial showed that adjunct short pulse MB+US therapy prior to and following PCI in first STEMI patients, improved angiographic recanalization prior to PCI and ejection fraction...
Phase-Contrast MRI (PC-MRI) is capable of 4D flow imaging and considered a gold standard for blood velocity measurements, but is currently cumbersome and time consuming. Ultrasound is bedside applicable, but is typically limited to a 1D velocity measurement. In this work we measure 3D blood flow velocity fields using high frame rate 3D ultrasound blood speckle tracking (BST) without contrast and compare...
Non-contrast blood perfusion imaging with ultrasound is difficult due to tissue clutter caused by patient physiological and sonographer hand motion. This motion causes spectral broadening of the tissue clutter signal, which then overlaps with the perfusion signal. To address this problem, we previously introduced an adaptive frequency and amplitude demodulation scheme to reduce the bandwidth of the...
Ultrafast plane wave microvessel imaging significantly improves ultrasound Doppler sensitivity. The rich spatiotemporal plane wave data enables robust clutter filtering based on singular value decomposition (SVD). However, due to the lack of transmit focusing, plane wave microvessel imaging is very susceptible to noise. The mid-to-deep region of the microvessel image is typically saturated by noise,...
Chronic kidney disease (CKD) affects over 8 million people in the United States and is a major risk factor for cardiovascular disease, hospitalization and death. Diagnosis is usually made with blood and urine tests, and imaging is used primarily to rule out obstruction or determine size. Blood and urine tests are also used to follow disease progression with imaging used only for specific situations...
Power Doppler (PD) is the preferred technique for accessing weakly scattering blood cells with low-velocity flow. However, strong clutter decreases sensitivity of the blood signals, which degrades micro-vasculature imaging. Eigen-based filtering methods have been developed to separate the independent scattering sources using both spatial and slow-time statistics of echo data. We recently found that...
A great need exists to non-invasively quantify the neurotransmitter activity in real-time to build a comprehensive functional map of a brain. In this paper, we present real-time recording of neuronal membrane potential change in vivo using transcranial photoacoustic (PA) voltage-sensitive dye (VSD) imaging on a rat in seizure.
The recent development of ultrafast ultrasound localization microscopy (Errico et al., Nature, 2015) provides new opportunities for imaging the vasculature with sub-diffraction resolution. However, the large number of images to be recorded requires acquisitions lasting several minutes. Therefore, physiological motion far larger than the achievable resolution presents challenges for moving tissues...
Vector Doppler techniques are ready to substituting the standard methods for blood velocity investigation. However, like in classic Pulse Wave methods, the maximum detectable velocity is related to the Pulse Repetition Frequency (PRF), which is limited by the maximum depth and/or hardware constraints. Unfortunately, the blood velocity, e.g. in stenotic vessels, can easily peak at 2m/s, thus resulting...
Rupture of an atherosclerotic plaque in the carotid artery is one of the main causes of stroke and stroke-induced death. Currently, to prevent this risk, endarterectomy is performed based on the stenosis grade assessed with Duplex ultrasound (US). However, plaque composition, e.g. presence of lipids and hemorrhages, is a more important factor of rupture risk than stenosis. The optical absorption of...
Pulse wave velocity and blood flow velocity are two different physiological parameters which are generally assessed using two different ultrasound sequences and processing techniques. This can be explained by the difference in term of signal intensity between the tissue and blood (approx. 40 dB). On one side, blood velocity can be estimated using Doppler, speckle tracking or transverse oscillation...
With identical exposures, enhanced cavitation resulting from increased microbubble (MB) concentrations has been demonstrated in the literature. Through the generation of a low-pressure trap, our previous work described a means to locally accumulate MBs within large vessel lumen (fig. a). But the existence of blood in-vivo could impede the MB translation and retention, which calls for preliminary investigations...
Ultrafast Ultrasound Localization Microscopy (uULM, Couture et al. IEEE IUS 2011) takes inspiration from the FPALM technique applied in optics as it relies on the detection of single scatters localized at a resolution below the half-wavelength theoretical limit. The tracking of microbubbles injected in the blood stream lead to unprecedented resolution for in-vivo imaging of the rat brain (Errico et...
Contrast-enhanced ultrasound (CEUS) permits quantification and monitoring of tumor vascular changes in response to anti-angiogenic treatment with the goal of informing targeted therapy. Conventional mean-intensity-based CEUS analysis discounts additional information that may be available from the first-order speckle statistics in a CEUS image. In this presentation, we demonstrate that our compound...
Left intraventricular blood vortices could provide important information on cardiovascular health. However they are not explicitly measured in current-day commercial systems. Additionally, the slow frame rates (typically <30Hz) of 2D cardiac Doppler imaging do not enable adequate sampling of the intraventricular blood dynamics. Finally, current imaging modes do not allow simultaneous estimation...
Histotripsy is a noninvasive ultrasound therapy that fractionates target tissues via cavitation. Our group has previously demonstrated that histotripsy can be delivered transcranially through excised human skulls to rapidly liquefy large volume clots for catheter aspiration using electronic focal steering (up to 40mL in 20 min) in an ex vivo ICH model. Transcranial MRgFUS has been investigated for...
Clinically used Intravascular Ultrasound (IVUS) imaging majorly operates in the 20∼40MHz range, providing resolution on the order of 100μm. Recent reports showed the potential of higher frequency (60–80MHz) of IVUS improving resolution to the level of 30–60μm, but still inferior to the resolution of OCT (10μm). Whether increasing the working frequency a step further could make IVUS comparable to OCT?...
Recently, ultrafast ultrasound imaging has been proposed for many clinical applications. However, most operational frequencies of ultrafast ultrasound imaging are around 3.5 to 15 MHz. Currently, ultrafast 40 MHz high frequency ultrasound imaging has been developed in our Lab. High frequency ultrasound is a good choice for blood flow mapping because the backscattering signals from blood is increased...
Human studies aimed at opening the blood brain barrier (BBB) to deliver therapeutic agents through a combination of focused ultrasound (US) and microbubbles (MB) are currently underway [1]. Our goal was to develop an US-guided BBB opening system capable of steering the US beam throughout the rodent brain and registering the coordinates with high field MRI. Our ultimate goal is to deliver therapy for...
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