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Contrast agent-free 3D ultrasound deep-depth vascular imaging with a 2D row column addressed Array: In vivo human clinical feasibility study

2026-01-12T12:40:12Z

Title: Contrast agent-free 3D ultrasound deep-depth vascular imaging with a 2D row column addressed Array: In vivo human clinical feasibility study Author(s): Guezzi, Nizar; Lee, Sangheon; Nam, Sangwoo; Jung, Dongkyu; Noman, Muhammad; Seong, Hyojin; Lee, Sanghoon; Kim, Hoe Joon; Yu, Jaesok Abstract: Three-dimensional (3D) imaging of vascular networks is essential for accurately diagnosing deep organ diseases. However, current ultrasound imaging methods are primarily limited to visualizing 2D cross-sections, which restricts the ability to evaluate the full structure of vascular networks. Although several 3D ultrasound techniques have been proposed to overcome this limitation, most struggle to achieve deep penetration and a wide field of view due to their high resource requirements. Row-column addressed arrays (RCAs) have emerged as a promising solution, enabling 3D imaging with significantly reduced hardware complexity. Nevertheless, the limited image quality achievable with RCAs has hindered their broader application. In this study, we propose a coded plane-wave-based, contrast-free 3D imaging system using RCAs for in vivo imaging of deep human vasculature. To validate the method, we imaged the liver and spleen of two healthy adult volunteers and successfully visualized vascular structures without contrast agent injection. Flow dynamics were captured at a frame rate of 27 Hz. Additionally, we demonstrated contrast-to-noise ratio (CNR) improvements of approximately 9 dB and 10 dB in the z-y and z-x planes, respectively, compared to non-coded excitation. This approach offers strong potential for in vivo 3D visualization and assessment of complex, deeply located vascular networks.

Optimized Coil Design for Enhanced Electric Field Induction in Peripheral Nerve Stimulation

2025-11-13T06:10:12Z

Title: Optimized Coil Design for Enhanced Electric Field Induction in Peripheral Nerve Stimulation Author(s): Park, Jaeu; Lee, Kyeong Jae; Nagwade, Pritish; Jeong, Jinwoong; Park, Jeong Hoan; Choi, Hongsoo; Kim, Sohee; Lee, Sanghoon Abstract: Peripheral nerve electrical stimulation is widely used for the treatment of neuropathic pain and neural regeneration. However, it often induces adverse biological reactions and unintended activation of surrounding neural tissues. As an alternative, peripheral nerve magnetic stimulation offers a promising, less invasive approach that enables targeted nerve stimulation without direct tissue contact. Despite its potential, it is constrained by the bulkiness of coils and excessive heat generation due to the high currents required. To address these limitations, we conducted a study on coil design optimized for peripheral nerve modulation. Our approach, supported by simulations and animal experiments, focused on optimizing coil geometry to maximize the induced electric field gradient. Among various designs, a four-leaf rhombus-shaped coil demonstrated the highest gradient at the center of the interface. In rat sciatic nerve experiments, this coil, driven by a rectangular pulse with a 200 μs rise time and 25 V amplitude, successfully elicited compound muscle action potentials in both the tibial anterior and gastrocnemius muscles. This study presents design guidelines for peripheral nerve stimulation (PNS) coils based on magnetic stimulation as an alternative to conventional electrical stimulation. The proposed approach may serve as a foundation for the development of advanced, miniaturized, and energy-efficient neural stimulation coils. © 2025 Elsevier B.V., All rights reserved.

Hexagonal metal complex based mechanically robust transparent ultrathin gold μECoG for electro-optical neural interfaces

2025-08-22T04:40:13Z

Title: Hexagonal metal complex based mechanically robust transparent ultrathin gold μECoG for electro-optical neural interfaces Author(s): Kim, Duhee; Bissannagari, Murali; Kim, Boil; Hong, Nari; Park, Jaeu; Lim, Hyeongtae; Lee, Junhee; Lee, Jungha; Kim, Yoon Kyoung; Cho, Youngjae; Lee, Kwang; Lee, Junghyup; Yoon, Jong-Hyeok; Jang, Jae Eun; Tsai, David; Lee, Sanghoon; Kwon, Hyuk-Jun; Choe, Han Kyoung; Kang, Hongki Abstract: Transparent electro-optical neural interfacing technologies offer simultaneous high-spatial-resolution microscopic imaging, and high-temporal-resolution electrical recording and stimulation. However, fabricating transparent, flexible, and mechanically robust neural electrodes with high electrochemical performance remains challenging. In this study, we fabricated transparent (72.7% at 570 nm), mechanically robust (0.05% resistance change after 50k bending cycles) ultrathin Au microelectrodes for micro-electrocorticography (mu ECoG) using a hexadentate metal-polymer ligand bonding with an EDTA/PSS seed layer. These transparent mu ECoG arrays, fabricated with biocompatible gold, exhibit excellent electrochemical properties (0.73 Omegacm2) for neural recording and stimulation with long-term stability. We recorded brain surface waves in vivo, maintaining a low baseline noise and a high signal-to-noise ratio during acute and two-week recordings. In addition, we successfully performed optogenetic modulation without light-induced artifacts at 7.32 mW/mm2 laser power density. This approach shows great potential for scalable, implantable neural electrodes and wearable optoelectronic devices in digital healthcare systems.

A stealthy neural recorder for the study of behaviour in primates

2025-07-25T02:46:46Z

Title: A stealthy neural recorder for the study of behaviour in primates Author(s): Oh, Saehyuck; Jekal, Janghwan; Won, Jinyoung; Lim, Kyung Seob; Jeon, Chang-Yeop; Park, Junghyung; Yeo, Hyeon-Gu; Kim, Yu Gyeong; Lee, Young Hee; Ha, Leslie Jaesun; Jung, Han Hee; Yea, Junwoo; Lee, Hyeokjun; Ha, Jeongdae; Kim, Jinmo; Lee, Doyoung; Song, Soojeong; Son, Jieun; Yu, Tae Sang; Lee, Jungmin; Lee, Sanghoon; Lee, Jaehong; Kim, Bong Hoon; Choi, Ji-Woong; Rah, Jong-Cheol; Song, Young Min; Jeong, Jae-Woong; Choi, Hyung Jin; Xu, Sheng; Lee, Youngjeon; Jang, Kyung-In Abstract: By monitoring brain neural signals, neural recorders allow for the study of neurological mechanisms underlying specific behavioural and cognitive states. However, the large brain volumes of non-human primates and their extensive range of uncontrolled movements and inherent wildness make it difficult to carry out covert and long-term recording and analysis of deep-brain neural signals. Here we report the development and performance of a stealthy neural recorder for the study of naturalistic behaviours in non-human primates. The neural recorder includes a fully implantable wireless and battery-free module for the recording of local field potentials and accelerometry data in real time, a flexible 32-electrode neural probe with a resorbable insertion shuttle, and a repeater coil-based wireless-power-transfer system operating at the body scale. We used the device to record neurobehavioural data for over 1 month in a freely moving monkey and leveraged the recorded data to train an artificial intelligence model for the classification of the animals’ eating behaviours. © The Author(s) 2024.