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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...
Hydroxyapatite (HAp) is a useful biocompatible material and is used for the surface coating of artificial bone. It has been reported that the oriented HAp promotes rapid recovery of the bone fracture[1], although most of coating HAp layers on the commercial artificial Titanium (Ti) bones are not oriented. As a new coating layer, our group has reported the highly oriented HAp film on Ti substrate fabricated...
Clinical studies using HRpQCT have revealed that cortical bone porosity is a major risk factor for fracture Not only average porosity but also pore size and local accumulation of large basic multicellular units (BMUs) have been associated with a reduction of the hip strength. However, an increase of cortical pore dimensions is poorly captured by X-ray based techniques. A previous in-silico study provided...
Osteoporosis is a skeletal disease which increases the risk of bone fracture. We have proposed a ultrasound technique for the early detection of osteoporosis using two wave phenomenon in cancellous bone. In this phenomenon, we can find the fast wave mainly propagating along trabeculae, and the slow wave propagating in the bone marrow [1]. In the early stage of osteoporosis, the medullary cavity (a...
Cortical bone is an anisotropic material with hierarchical structure whose elastic properties are described at different length scales. At millimeter-scale, the whole set of stiffness tensor can be conveniently measured by resonant ultrasound spectroscopy (RUS). At microscopic-scale, micro-indentation and scanning acoustic microscopy are often used to quantify tissue matrix elastic properties. However,...
Bone quality encompasses bone properties that contribute to fracture risk, such as bone stiffness, microstructure, matrix constituents or tissue material properties. These aspects cannot be quantified in-vivo except for stiffness, a surrogate biomarker of strength, which can be assessed using quantitative ultrasound techniques. To better predict bone fracture risk, investigating the relationships...
The postmenopausal osteoporosis is likely influenced by the events taking place during bone development [1]. To prevent future risk of osteoporosis, the appropriate growth of bone during teenagers is important. The ultrasonic bone densitometry is portable and has no radiation exposure, which is suitable for the evaluation of children's bone. In this study, an ultrasonic bone measurement system of...
The oscillation of microbubbles has long been hypothesized to provide the opportunity to enhance gene delivery as a result of changes in membrane permeability; however, translationally-relevant therapeutic protocols have not yet been realized. We sought to develop and validate a protocol to transfect endogenous mesenchymal stem cells (MSCs) via the local injection of plasmids and microbubbles and...
Lumbar puncture (LP) procedures are facilitated by palpation-based techniques in which the needle insertion location is determined by palpating spinous processes to identify the vertebral level and midline. Not surprisingly, the efficacy of this technique decreases in obese patients and in patients with spinal deformities. Ultrasound imaging significantly improves LP success rates in these difficult...
Cortical bone porosity (Ct. Po) and pore diameter (Po. Dm) are important factors in determining bone toughness and strength [1–2]. However, the current standard diagnosis, dual-energy X-ray absorptiometry (DXA), doesnot have the sensitivity to those factors. Due to the strong specular reflection from the bone surface and high acoustic attenuation of cortical bone tissue, conventional ultrasound is...
One of the challenges in ultrasound bone imaging is related to the specular reflection in the soft tissue-bone interface. Since the transmit ultrasound beam is not necessarily perpendicular to the bone surface, the reflected ultrasound signals from bones are often tilted in the channel data. Even though the amount of tilting may not be large, this can still result in cancellation of the bone signals...
We have investigated the feasibility of imaging cortical pores using ultrasound contrast agents (UCA). Cortical bone porosity and pore size are major factors in determining bone strength and toughness. Assessments on cortical pore properties can help to predict and prevent bone fractures. Because cortical pores are highly associated with blood vessels, imaging cortical bone microvascular perfusion...
Radiotherapy aims at irradiating tumor tissue, while sparing normal tissue as much as possible and it is a suitable treatment option for prostate cancer. A crucial aspect of the radiotherapy workflow is patient positioning. It has been shown that frequent imaging during the course of the treatment (image guided radiotherapy) can improve this positioning accuracy. Despite the many advantages of ultrasound...
One of the challenges in ultrasound bone imaging is related to the specular reflection in the soft tissue-bone interface. Since the transmit ultrasound beam is not necessarily perpendicular to the bone surface, the reflected ultrasound signals from bones are often tilted in the channel data. Even though the amount of tilting may not be large, this can still result in cancellation of the bone signals...
Workers who are repeatedly exposed to high cyclic loading are at high risk for degenerative cervical spine disease. Standard methods to evaluate spine motion using optical tracking or dual fluoroscopy are impractical for imaging patients in the work environment. Portable ultrasound can image cervical spine kinematics in real time, and may be able to detect abnormal spine function not apparent by static...
A mathematical model to predict the ultrasonic attenuation coefficient as a function of frequency in cortical bone is proposed, and the effects of micro-architectural changes on model parameters are studied in this work. Spectroscopy was performed in numerical finite differences time domain simulations to study the individual effects of pore diameter on ultrasonic attenuation. The attenuation coefficient...
The non-invasive cortical bone quality assessments using ultrasound axial transmission technique have attracted strong attention. The estimation of phase velocity and attenuation of absorbing plate should help the assessment. To get the high-resolution estimation, we employ an adaptive beamforming technique that uses an eigenvalue decomposition. The technique can estimate not only the phase velocities...
In the early stage of osteoporosis, the medullary cavity (a hole in the cancellous bone) becomes larger in addition to the decrease of bone volume. The effects of such structural changes seem important to understand the process of osteoporosis. In this study, we experimentally studied effects of medullary cavity on the two wave phenomenon. The slow wave amplitudes decreased with the decrease of the...
Transcranial focused ultrasound is approved for non-invasive treatment of essential tremor, and is being researched as a noninvasive means of ablating brain tumors, neuromodulation, and of increasing delivery of cancer therapeutics through the blood-brain barrier. Present technology relies on the use of an array of transducers placed in a helmet and aimed at the skull at normal incidence, leading...
Palpation-based techniques are the most common approaches for facilitating lumbar spine bedside procedures such as lumbar puncture and spinal and/or epidural placement. However, the efficacy of these approaches is diminished in patients whose surface landmarks are difficult to palpate due to obesity or spinal deformities. In this work, we present the imaging results of a handheld ultrasound system...
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