The hip joint center (HJC) is needed for calculation of hip kinematics in various applications. In the functional method, the center is determined by moving femur with respect to acetabulum. A popular way for measuring this movement is through an optical motion capture system. This method is fast and economical for most applications where we require an instant HJC even though the reconstruction error in bone position calculation exists due to skin artifact. This error is caused by movement of markers placed on skin rather than on actual bone. Here we introduce ultrasound imaging as an additional modality to measure the change in soft tissue thickness above bone while hip is flexed. We use this information on the tissue thickness change to recalculate position of markers placed on skin to match the movement of bone. A good advantage of using ultrasound machine is its non-invasiveness. We calculated HJC using a symmetric center of rotation estimation (SCoRE) algorithm, which uses the concept of coordinate transformation on 3D marker position data. The algorithm gives the 3D position of two centers, one for each hip bone. The distance between these two centers (SCoRE residual) gives us a hint on the accuracy of the HJC calculation and has been proved to be proportional to the error with respect to actual center in previous studies. These two centers should ideally coincide as they collectively form a spherical joint. Our new algorithm for HJC calculation with tissue thickness compensation, measured using ultrasound imaging shows the error has been reduced from 9.13 mm to 4.87 mm

acase@tulane.edu / Cancer’s response to mechanical vibration via high-intensity focused ultrasound and disruptive chemical agents (Mechanochemical Disruption) was examined in vitro and in vivo. We demonstrated that mechanochemical disruption of cellular structures induced phenotypic alterations in surviving tumor cells that prevented cancer progression. Mechanochemical disruption inhibited uncontrolled proliferation, tumorigenicity, metastatic development, and re-sensitized multiple cancer types to chemical treatment via alterations in protein expression and impediment of pro-survival signaling. Our study identified a novel curative therapeutic approach that can prevent the development of aggressive cancer phenotypes. / 1 / hakm murad

We report a case where colonoscopic ultrasound was used to evaluate the pancreas. In this case the usual method of evaluating the body of the pancreas by upper gastrointestinal ultrasound was unsuccessful because of the presence of a large hiatal hernia. The other abdominal organs evaluated by colonoscopic ultrasound included the ileo-cecal valve, kidney, liver spleen and prostate. To our knowledge this is the first case where ultrasonic colonoscope has been used to evaluate the body of the pancreas.

Background: Determination of intra-abdominal injury following blunt abdominal trauma (BAT) continues to be a diagnostic challenge. Ultrasound (US) bas been described as a potentially useful diagnostic tool in this setting and is being used with increasing frequency in trauma centers. We determined the diagnostic capability of US in the evaluation of BAT. Methods: A retrospective analysis of our trauma US database was performed over a 30-month period. Computed tomographic scan, diagnostic peritoneal lavage, or exploratory laparotomy confirmed the presence of intra-abdominal injury. Results: During the study period, 8,197 patients were evaluated at the Ryder Trauma Center. Of this group, 2,576 (31%) had US in the evaluation of BAT. Three hundred eleven (12%) US exams were considered positive. Forty-three patients (1.7%) had a false-negative US; of this group, 10 (33%) required exploratory laparotomy. US had a sensitivity of 86%, a specificity of 98%, and an accuracy of 97% for detection of intra-abdominal injuries. Positive predictive value was 87% and negative predictive value was 98%. Conclusion: Emergency US is highly reliable and may replace computed tomographic scan and diagnostic peritoneal lavage as the initial diagnostic modality in the evaluation of most patients with BAT.

Intelligent Transportation Systems and supporting technologies have been an active area of research for some time. Human drivers exhibit slower response times and errors in judgment that can have serious adverse affects on traffic flow. These types of errors can be reduced or eliminated from the driving experience by introducing computer control systems into the automotive arena. The purpose of this research was to develop a scale model platform for the rapid prototyping and testing of ITS systems and technologies. Specifically, this body of work was concerned with the development of an automatic headway control system that utilized ultrasonic sensors. This control system was intended to automatically maintain headway distance in an effort to create an adaptive cruise control system for this scale model vehicle. Implementation of such systems could conceivably reduce driver fatigue by removing the burden of maintaining safe following distance from the driver. System dynamics of car-like robots with nonholonomic constraints were employed in this research to create a controller for an autonomous path following vehicle. The application of a working kinematic model describing car-like robotic systems allowed the development of a simple first order controller, as well as a sliding mode controller. Following the development and simulation of these two control laws, the system was applied to the FLASH project scale model vehicle to assess the practical use of the system on a mock highway. A satisfactory result is produced after testing was completed, and the application of such systems to scale model platforms is feasible. / Master of Science

Introduction: Implicit within spinal manipulative therapy is the assumption that treatment loads are effectively transcribed to actuate consistent mechanisms for expected clinical results. There is conflicting evidence between the mechanistic understandings and the physiologic responses from experimental evidence. Greater clarity on how loads are transferred through tissues to the target sites would be useful in enhancing utilization and efficacy of spinal manipulative procedures. Purpose: Directly monitor displacement of tissue in strata at sequential depths between the load application site and target articulation in the thoracic spine. Tissue displacement served as a surrogate for evidence of load transmission. Methods: Ultrasound elastography techniques monitored displacement in sequential strata while electromyographic signals, force, kinematic motions were monitored synchronously. Volunteers were placed prone on a treatment table, while a typical spinal manipulative pre-load maneuver was applied in the thoracic spine. Results: When applying a therapeutic load to the skin the results demonstrate with increasing depth of tissue there is a sequentially decreasing rank order in the mean cumulative displacement with each layer being significantly greater than the deeper adjacent layer. Superficial loose connective tissue layer (0.34 mm ± 0.15) vs. intermediate muscle layer (0.28 mm ± 0.11), p=0.004. Intermediate muscle layer (0.28 mm ± 0.11) vs. deep muscle layer (0.16 mm ± 0.6), p<0.0001. Filtered myoelectric signals were linearly correlated with tissue strata cumulative displacements, but the relationship was not strong (-0.23 < r < 0.46). Conversely, Pearson correlation analysis revealed strong and relatively stable correlations (0.74 < r < 0.90) for the association between displacement at the load application site and tissue layers. Conclusion: The sequential tissue motion demonstrates that some degree of load transfer through layers occurs. Both direct and indirect stimulation of tissues across both depth and breadth is feasible, to an extent consistent with the stimulation of mechanoreceptors. / Thesis / Master of Science (MSc)

Ultrasound (US) has become a standard procedure used during pregnancy to document the health and development of a fetus. When ultrasound was first developed, some researchers urged caution, suggesting that the possibility of hazard should be kept under constant review. Given the routine application of fetal ultrasound imaging, any possibility of deleterious developmental effects resulting from its use is an important public health issue. Rats have a well characterized central nervous system whose neurochemical pathways and neuronal electrophysiology qualitatively correspond to those of humans. Because of this, we opted to use Wistar rats as an animal model to document effects from ultrasound exposure. We exposed one group of rats on prenatal days 15 and 20 for fifteen minutes. A control group was exposed subjected to similar conditions, however no ultrasound exposure was given. A third group was exposed for ten minutes each on post natal days (PND) 2 and 3 while a fourth control group was exposed to the same conditions as group three with no ultrasound exposure. The rats were then watched for developmental delays. When the rats reached the appropriate age, they were given a locomotor task to test for appropriate motor responses. Acoustic startle and prepulse inhibition tests were administered to test for sensorimotor gating, hearing, and motor response. Finally, a brainstem auditory evoke potential test was given to track auditory threshold and appropriate neural firing at various auditory nuclei. Postnatally US exposed rats showed a decreased acoustic startle response and prenatally exposed rats exhibited a speeding up in components of the brainstem auditory evoked potential test.

Cell modulation poses an invaluable role in understanding the biophysics, deciphering the neural circuits, and exploring clinical treatment of diseases. Optoacoustic cell modulation is an emerging modality benefiting from the merits of ultrasound with high penetration depth as well as photons with high spatial precision. My thesis work focused on the development of a fiber optoacoustic emitter for neural stimulation and the study of biomolecular mechanisms underlying optoacoustic cell modulation. To enable region specific and high-efficiency cell modulation, we developed a fiber-based optoacoustic emitter (FOE), serving as a miniaturized ultrasound point source, with sub-millimeter confinement. By modifying acoustic damping and light absorption performance, controllable frequencies in the range of 0.083 MHz to 5.500 MHz are achieved and further induce cell membrane sonoporation with frequency dependent efficiency. These data demonstrate the potential of FOE in region-specific drug delivery, gene transfection and neurostimulation. To achieve neuromodulation at single cell spatial resolution, we further developed a tapered fiber optoacoustic emitter (TFOE) enabling stimulation of single neurons and subcellular structures. The highly confined ultrasound enabled integration of the optoacoustic stimulation with stable patch clamp recording on single neurons for the first time. Cell-type-specific response of excitatory and inhibitory neurons to acoustic stimulation was unveiled. Towards understanding the biomolecular mechanisms of optoacoustic cell modulation, we show that optoacoustic excites primary cortical neurons through specific calcium-selective mechanosensitive ion channels with the assistant of calcium amplifier channel and voltage-gated channels. Pharmacological inhibition of specific ion channels leads to reduced responses, while over-expressing these channels results in stronger stimulation. These results shed new insights into the mechanism of ultrasound neurostimulation. Together, these findings offer a platform for understanding the mechanism of acoustic cell modulation as well as non-genetic, high precision cell modulation method enabling treatment of diseases. / 2025-09-21T00:00:00Z

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