IEEE International Ultrasonics Symposium : [proceedings]

SUper-Resolution ultrasound imaging using Erythrocytes (SURE) creates microvascular images without any contrast agent injection, with only a few seconds of acquisition time. This paper hypothesizes that it is possible to reveal the microvascular density and velocity estimation of a human mole without the use of contrast agents, with just two seconds of data acquisition. In this study, imaging results from a single volunteer are presented. The SURE density image obtained using a Verasonics research scanner is compared with the Power Doppler image acquired from a commercial GE LOGIQ E9 scanner. The SURE tracking pipeline successfully visualized and estimated the velocity map and velocity profile of vessels as small as 65 mu m in diameter, with flow velocities as low as 3.2 mm/s. It shows the feasibility of visualizing the vasculature of benign moles, which potentially can assist medical doctors in distinguishing between benign and malignant moles and prioritizing them for further investigation.

Osseointegration is the main criterion for implantation success and remains a major challenge during implant development and patient treatment. Since conventional testing does not allow for accurate identification of implant loosening, we developed a new test stand where acoustic emission analysis is applied to the push-out testing process. This allows for more accurate data on implant loosening with similar loading conditions. This study investigates the interaction of mechanical behavior and acoustic emission (AE) characteristics of pork bone and sawbone samples during a combined push-out test. The primary aim is to analyze the AE data and correlate acoustic parameters. Therefore, 11 bone-implant samples of each material have been tested in a push-out process and analyzed with regards to the AE parameters. We conclude that identification of fracture types - shear or tensile - via rise angle and average frequency is a crucial step in the early detection of implant loosening. Although sawbone samples provide high reproducibility, they do not perfectly mimic natural bone, and animal bone offers more realistic results. Therefore, the proposed testing method is a promising tool for more accurate evaluation of bone-implant interactions in future osseointegrated samples.

Capacitive micromachined ultrasonic transducers (CMUTs) feature small size, wide bandwidth and good matching with acoustic impedance of water. The application of CMUTs in underwater sensing systems has the potential to reduce power consumption and save space. However, compared to traditional piezoelectric transducer, CMUTs exhibit lower sensitivity. To address this issue, this study designed a high-sensitivity CMUT device by reducing the silicon membrane thickness and optimizing the thickness of package material, and then characterized its acoustic performance. The results indicate that the CMUT exhibits significant advantages in terms of transmit sensitivity and bandwidth, and holds potential for applications in underwater sensing systems.

Cutaneous leishmaniasis (CL) is the most common form of leishmaniasis, manifesting as skin lesions that can lead to scarring and may have lifelong impacts on wellbeing. Early and accurate assessment of lesion biomechanics could enhance diagnosis and therapeutic monitoring. In this study, we evaluate the feasibility of four-dimensional (4D) dynamic optical coherence elastography (OCE) for in vivo characterization of CL lesions in murine model. Four mice at distinct disease stages: healthy baseline, day 1 post-infection, developed lesion, and post-treatment, were scanned. Volumetric elasticity values were obtained by calculating local elastic wave velocities. Healthy skin exhibited uniform wave propagation with an average Young's modulus of 19 +/- 2 kPa, and a similar value was observed at day 1 post-infection (20 +/- 5 kPa). In contrast, developed lesions displayed markedly increased stiffness (511 +/- 238 kPa), which decreased following treatment (68 +/- 27 kPa). These findings demonstrate that 4D dynamic OCE can quantitatively and non-invasively detect biomechanical changes associated with CL progression and treatment response, supporting its potential as a diagnostic and monitoring tool in clinical settings.

Intravascular ultrasound (IVUS) serves as an important imaging technique for the diagnosis of cardiovascular diseases (CVDs). Commercial IVUS catheters use either a side-looking rotating transducer or a circumferential transducer array to provide cross-sectional ultrasound (US) images. However, it cannot visualize the path ahead of the catheter, which is necessary for applications such as chronic total occlusion (CTO) angioplasty. This study proposes a concept dual-mode magnetic US catheter, mainly consisting of a magnetic component and two miniature high-frequency US transducers, which can perform both forward-looking sectorial scanning and side-looking circular scanning B-mode US imaging by remote magnetic actuation. The fabricated prototype catheter has an outer diameter of 1.8 mm. The center frequencies of the two transducers are both 30 MHz. Preliminary experiments are conducted to validate the effectiveness.