Koh Young Technology, Inc.

Cardiovascular disease is the leading global cause of death. In arterial health assessment, pressure waveform morphology provides valuable diagnostic information, yet the relationship between waveform changes and physiological parameters remains incompletely understood. To address this gap, this study examines how arterial stiffness (E), heart rate (HR), and stroke volume (SV) affect waveform morphology similarity (WMS) between arterial measurement points and investigates its relationship with relative pulse transit time (RPTT)-pulse transit time normalized by cardiac cycle. Using Cardiovascular hardware simulator and hemodynamic model (pulse pressure mean absolute error = 1.96 ± 1.65 mmHg), each physiological factor's influence was isolated through parametric studies. Results showed E and HR impact waveform morphology, while SV primarily affects pulse pressure magnitude without altering waveform characteristics. Based on these findings, analysis revealed correlations between RPTT and both WMS (experimental Spearman r = -0.982) and pulse pressure amplification ratio (experimental Spearman r = 0.934). Notably, different E-HR combinations yielding similar RPTT values produced nearly identical waveform propagation patterns, establishing RPTT as an integrated indicator of pulse wave dynamics. Leveraging this relationship, the WMS-RPTT relationship was utilized to develop a carotid-femoral pulse wave velocity estimation method tested in a 56-artery numerical model (Pearson r = 0.920, RMSE = 0.65 m/s). This approach may offer potential advantages by incorporating waveform information, suggesting possibilities for non-invasive assessment through peripheral measurements, and potentially contributing to our understanding of pulse wave changes across different physiological conditions, which could enhance arterial hemodynamics insights for cardiovascular risk assessment.

To extend the field of view while reducing dimensions of the C-arm, we propose a carbon nanotube (CNT)-based C-arm computed tomography (CT) system with multiple X-ray sources. A prototype system was developed using three CNT X-ray sources, enabling a feasibility study. Geometry calibration and image reconstruction were performed to improve the quality of image acquisition. However, the geometry of the prototype system led to projection truncation for each source and an overlap region of object area covered by each source in the two-dimensional Radon space, necessitating specific corrective measures. We addressed these problems by implementing truncation correction and applying weighting techniques to the overlap region during the image reconstruction phase. Furthermore, to enable image reconstruction with a scan angle less than 360°, we designed a weighting function to solve data redundancy caused by the short scan angle. The accuracy of the geometry calibration method was evaluated via computer simulations. We also quantified the improvements in reconstructed image quality using mean-squared error and structural similarity. Moreover, detector lag correction was applied to address the afterglow observed in the experimental data obtained from the prototype system. Our evaluation of image quality involved comparing reconstructed images obtained with and without incorporating the geometry calibration results and images with and without lag correction. The outcomes of our simulation study and experimental investigation demonstrated the efficacy of our proposed geometry calibration, image reconstruction method, and lag correction in reducing image artifacts.

Objectives. This study aimed to investigate whether optical coherence tomography (OCT) provides useful information about the microstructures of the middle and inner ear via extratympanic approach and thereby could be utilized as an alternative diagnostic technology in ear imaging.Methods. Five rats and mice were included, and the swept-source OCT system was applied to confirm the extent of visibility of the middle and inner ear and measure the length or thickness of the microstructures in the ear. The cochlea was subsequently dissected following OCT and histologically evaluated to compare with the OCT images.Results. The middle ear microstructures such as ossicles, stapedial artery and oval window through the tympanic membrane with the OCT could be confirmed in both rats and mice. It was also possible to obtain the inner ear images such as each compartment of the cochlea in the mice, but the bone covering bulla needed to be removed to visualize the inner ear structures in the rats which had thicker bulla. The bony thickness covering the cochlea could be measured, which showed no significant differences between OCT and histologic image at all turns of cochlea.Conclusion. OCT has been shown a promising technology to assess real-time middle and inner ear microstructures noninvasively with a high-resolution in the animal model. Therefore, OCT could be utilized to provide additional diagnostic information about the diseases of the middle and inner ear.