Artificial Intelligence-Enhanced Quantitative Ultrasound for Breast Cancer: Pilot Study on Quantitative Parameters and Biopsy Outcomes.

Traditional B-mode ultrasound has difficulties distinguishing benign from malignant breast lesions. It appears that Quantitative Ultrasound (QUS) may offer advantages. We examined the QUS imaging system's potential, utilizing parameters like Attenuation Coefficient (AC), Speed of Sound (SoS), Effective Scatterer Diameter (ESD), and Effective Scatterer Concentration (ESC) to enhance diagnostic accuracy. B-mode images and radiofrequency signals were gathered from breast lesions. These parameters were processed and analyzed by a QUS system trained on a simulated acoustic dataset and equipped with an encoder-decoder structure. Fifty-seven patients were enrolled over six months. Biopsies served as the diagnostic ground truth. AC, SoS, and ESD showed significant differences between benign and malignant lesions (p < 0.05), but ESC did not. A logistic regression model was developed, demonstrating an area under the receiver operating characteristic curve of 0.90 (95% CI: 0.78, 0.96) for distinguishing between benign and malignant lesions. In conclusion, the QUS system shows promise in enhancing diagnostic accuracy by leveraging AC, SoS, and ESD. Further studies are needed to validate these findings and optimize the system for clinical use.

Dynamic Alterations in Cerebral Hemodynamics Measured by Portable Near-Infrared Spectroscopy in Orthostatic Hypotension and Intolerance.

BACKGROUND: We aimed to evaluate dynamic alterations in cerebral total hemoglobin concentration (HbT) in individuals with orthostatic hypotension (OH) and orthostatic intolerance (OI) symptoms using a portable near-infrared spectroscopy (NIRS) system. METHODS: Participants comprised 238 individuals (mean age, 47.9 years) without a history of cardiovascular, neurodegenerative, or cerebrovascular diseases, including those with unexplained OI symptoms and healthy volunteers. Participants were categorized by the presence of OH based on the supine-to-stand blood pressure (BP) drop and OI symptoms using on OH questionnaires: classic OH (OH-BP), OH symptoms alone (OH-Sx), and control groups. Random case-control matching sets were constructed, resulting in 16 OH-BP and 69 OH-Sx-control sets. The time-derivative of HbT change in the prefrontal cortex during the squat-to-stand maneuver was measured using a portable NIRS system. RESULTS: There were no differences in demographics, baseline BP, and heart rate among matched sets. The peak time of maximum slope variation in HbT change, indicating the recovery rate and speed of cerebral blood volume (CBV) change, was significantly longer in OH-Sx and OH-BP groups than in the control group under transition to a standing position after squatting. In the OH-BP subgrouping, the peak time of maximum slope variation in HbT change was significantly longer only in OH-BP with OI symptoms, but did not differ between OH-BP without OI symptoms and controls. CONCLUSIONS: Our results suggest that OH and OI symptoms are associated with dynamic alterations in cerebral HbT. Regardless of the severity of the postural BP drop, OI symptoms are associated with prolonged CBV recovery.

Calcium-Modified Silk Patch as a Next-Generation Ultrasound Coupling Medium.

There is an increasing interest in developing next-generation wearable ultrasound patch systems because of their wide range of applications, such as home healthcare systems and continuous monitoring systems for physiological conditions. A wearable ultrasound patch system requires a stable interface to the skin, an ultrasound coupling medium, a flexible transducer array, and miniaturized operating circuitries. In this study, we proposed a patch composed of calcium (Ca)-modified silk, which serves as both a stable interface and a coupling medium for ultrasound transducer arrays. The Ca-modified silk patch provided not only a stable and conformal interface between the epidermal ultrasound transducer and human skin with high adhesion but also offered acoustic impedance close to that of human skin. The Ca-modified silk patch was flexible and stretchable (∼400% strain) and could be attached to various materials. In addition, because the acoustic impedance of the Ca-modified silk patch was 2.15 MRayl, which was similar to that of human skin (1.99 MRayl), the ultrasound transmission loss of the proposed patch was relatively low (∼0.002 dB). We also verified the use of the Ca-modified silk patch in various ultrasound applications, including ultrasound imaging, ultrasound heating, and transcranial ultrasound stimulation for neuromodulation. The comparable performance of the Ca-modified patch to that of a commercial ultrasound gel and its durability against various environmental conditions confirmed that the Ca-modified silk patch could be a promising candidate as a coupling medium for next-generation ultrasound patch systems.

Robust Single-Probe Quantitative Ultrasonic Imaging System With a Target-Aware Deep Neural Network.

OBJECTIVE: The speed of sound (SoS) has great potential as a quantitative imaging biomarker since it is sensitive to pathological changes in tissues. In this paper, a target-aware deep neural (TAD) network reconstructing an SoS image quantitatively from pulse-echo phase-shift maps gathered from a single conventional ultrasound probe is presented. METHODS: In the proposed TAD network, the reconstruction process is guided by feature maps created from segmented target images for accuracy and contrast. In addition, the feature extraction process utilizes phase difference information instead of direct pulse-echo radio frequency (RF) data for robust image reconstruction against noise in the pulse-echo data. RESULTS: The TAD network outperforms the fully convolutional network in root mean square error (RMSE), contrast-to-noise ratio (CNR), and structural similarity index (SSIM) in the presence of nearby reflectors. The measured RMSE and CNR are 5.4 m/s and 22 dB, respectively with the tissue attenuation coefficient of 2 dB/cm/MHz, which are 72% and 13 dB improvement over the state of the art design in RMSE and CNR, respectively. In the in-vivo test, the proposed method classifies the tissues in the neck area using SoS with a p-value below 0.025. CONCLUSION: The proposed TAD network is the most accurate and robust single-probe SoS image reconstruction method reported to date. SIGNIFICANCE: The accuracy and robustness demonstrated by the proposed SoS imaging method open up the possibilities of wide-spread clinical application of the single-probe SoS imaging system.

The slope of cerebral oxyhemoglobin oscillation is associated with vascular reserve capacity in large artery steno-occlusion.

Inadequate cerebral perfusion is a risk factor for cerebral ischemia in patients with large artery steno-occlusion. We investigated whether prefrontal oxyhemoglobin oscillation (ΔHbO2, 0.6-2 Hz) was associated with decreased vascular reserve in patients with steno-occlusion in the large anterior circulation arteries. Thirty-six patients with steno-occlusion in the anterior circulation arteries (anterior cerebral artery, middle cerebral artery, and internal carotid artery) were included and compared to thirty-six control subjects. Patients were categorized into two groups (deteriorated vascular reserve vs. preserved vascular reserve) based on the results of Diamox single- photon emission computed tomography imaging. HbO2 data were collected using functional near-infrared spectroscopy. The slope of ΔHbO2 and the ipsilateral/contralateral slope ratio of ΔHbO2 were analyzed. Among the included patients (n = 36), 25 (69.4%) had deteriorated vascular reserve. Patients with deteriorated vascular reserve had a significantly higher average slope of ΔHbO2 on the ipsilateral side (5.01 ± 2.14) and a higher ipsilateral/contralateral ratio (1.44 ± 0.62) compared to those with preserved vascular reserve (3.17 ± 1.36, P = 0.014; 0.93 ± 0.33, P = 0.016, respectively) or the controls (3.82 ± 1.69, P = 0.019; 0.94 ± 0.29, P = 0.001). The ipsilateral/contralateral ΔHbO2 ratio could be used as a surrogate for vascular reserve in patients with severe steno-occlusion in the anterior circulation arteries.

E-TUBE: dielectric waveguide cable for high-speed communication.

The demand for advanced interconnects to satisfy market requirements on bandwidth, cost, and power is ever increasing with the expansion of data centers. An interconnect called E-TUBE is presented as a cost-and-power-efficient all-electrical-domain wideband waveguide solution for high-speed high-volume short-reach communication links. The E-TUBE achieves an unprecedented level of throughput-distance product, bending radius, and channel density without requiring complex manufacturing process. The E-TUBE link demonstrates nearly 25 GHz bandwidth at a carrier frequency of 70 GHz and exhibits a frequency-independent insertion loss of 5 dB/m with a frequency-independent group delay of 4 ns/m. Such loss and delay characteristics independent of frequency enabled broadband data transmission over extended reach compared to conventional waveguide links. The E-TUBE link transmits 25 Gbps NRZ data over 3 m distance using a 70 GHz RF CMOS transceiver IC, which is the state-of-the-art throughput-reach product. This new interconnect is expected to overcome the limitations of existing electrical and optical interconnects and to replace them in high throughput links, including but not limited to, 100/400 Gbps board-to-board communications.

Prognostication of neurological outcome after cardiac arrest using wavelet phase coherence analysis of cerebral oxygen.

BACKGROUND: The prognosis for cardiac arrest (CA) is associated with the degree of cerebral ischemia. We investigated the relationship between the wavelet coherence of cerebral oxyhemoglobin (HbO2) among different channels and outcomes after CA. Moreover, we aimed to develop a prognostication method after CA. METHODS: Eighty-three post-resuscitation patients were included. The HbO2 data were collected during the post-resuscitation period (median day, 1) using functional near-infrared spectroscopy. The coherence between sections of prefrontal HbO2 oscillations in five frequency intervals (I, 0.6-2 Hz; II, 0.15-0.6 Hz; III, 0.05-0.15 Hz; IV, 0.02-0.05 Hz; and V, 0.0095-0.02 Hz) were analyzed. We evaluated the outcomes using cerebral performance category (CPC) scores (good outcome, CPC ≤ 2 and poor outcome, CPC ≥ 3) at 3 months after CA. Additionally, the predictive method was developed using the biomarker and coherence value after CA. RESULTS: Among the included patients, 19 patients (22.9%) had a good outcome. Poor outcome group had significantly lower phase coherence in the myogenic frequency interval III compared to good outcome group (0.36 ±â€¯0.14 vs. 0.54 ±â€¯0.18, P < 0.001). The predictive method using neuron-specific enolase (NSE) and interval III value demonstrated good discrimination (area under the curve 0.919; 95% confidence interval, 0.850-0.989). CONCLUSIONS: The predictive method using NSE and phase coherence of HbO2 in the interval III from the vascular smooth muscle cells could be a useful tool for prognosticating after CA. This suggests that evaluating cerebral ischemia using phase coherence of HbO2 might be a helpful outcome predictor following CA.

A Reference-Less Time-Division-Duplex Transceiver IC for a 5-Fr 6-Electrode Renal Denervation Catheter in 0.18-µm 70-V BCDMOS.

This paper presents the first time-division-duplex transceiver IC for a 5-Fr 6-electrode renal denervation (RDN) catheter for treatment of resistant hypertension. Each IC encapsulated in a platinum electrode implements an RDN catheter with 37.5 % of diameter reduction, which enables minimally invasive surgery with reduced complications. The six electrodes sharing only four electrical wires perform packet communication with an external power control unit for independent operation and deliver the designated RF energy to the renal artery wall while measuring local temperature and impedance. Two 500- kHz 21-Vrms AC signals with ±35-V DC potentials are used as supplies to transfer up to 6-W RF ablation signal with 120-Vpp swing while maintaining the maximum DC supply voltages of the ICs less than the break-down voltage of 70 V. The proposed RDN IC fabricated in 0.18-µm HV BCDMOS occupies 2.1 mm2.

Early Detection of Cerebral Infarction With Middle Cerebral Artery Occlusion With Functional Near-Infrared Spectroscopy: A Pilot Study.

Background: NIRSIT, a functional near-infrared spectroscopy (fNIRS) device with 204 channels, can measure oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR) in non-pulsatile blood flow non-invasively using the absorption difference between HbO2 and HbR at a wavelength of 700-1,000 nm and can display the perfusion status in real time. Objective: We applied NIRSIT to patients with stroke to evaluate the usefulness of NIRSIT as an fNIRS device for the early detection of stroke. Methods: We performed a prospective pilot study in an emergency department (ED). Adult patients who had suspected symptoms and signs of stroke within 12 h of the first abnormal time and who underwent intravenous thrombolysis (IVT) or intra-arterial thrombectomy with acute middle cerebral artery (MCA) or internal carotid artery (ICA) infarction were enrolled. NIRSIT was applied to the patients before the imaging study, and the perfusion status of the brain was displayed in real time at the bedside. We compared the NIRSIT results with the mean transit time (MTT) map from perfusion computed tomography (PCT) and the time-to-peak (TTP) map from perfusion-weighted magnetic resonance imaging (PWI). Results: Six male and three female patients were enrolled, and the median age was 74 years. The most common symptom was unilateral extremity weakness (77.8%), followed by dysarthria (33.3%) and aphasia (11.1%). The median National Institutes of Health Stroke Scale (NIHSS) score was 17. All cases of MCA infarction showed different cerebral oxygen saturation values between bilateral lobes of the brain in fNIRS imaging, and these values matched the PCT and PWI results. Conclusions: The brain hemisphere with low oxygen saturation on fNIRS showed hypoperfusion on PCT or PWI. The fNIRS device could be useful in assessing the perfusion status of the brain and detecting MCA or ICA infarction in real time at the bedside.

Assessment of cerebral autoregulation using continuous-wave near-infrared spectroscopy during squat-stand maneuvers in subjects with symptoms of orthostatic intolerance.

Orthostatic lightheadedness in healthy young adults often leads to syncope in severe cases. One suggested underlying mechanism of orthostatic lightheadedness is a drop in transient blood pressure (BP); however, a decrease in BP does not always lead to a drop in cerebral blood flow (CBF) due to cerebral autoregulation (CA). We present a direct assessment method of CA using a multichannel continuous-wave near-infrared spectroscopy (CW-NIRS) device that measures the temporal changes in oxy- and deoxy-hemoglobin concentrations in the prefrontal cortex. Twenty healthy young adults were recruited. During the experiment, continuous beat-to-beat BP and heart rate were simultaneously measured during repetitive squat-stand maneuvers. We introduce a new metric termed 'time-derivative hemodynamic model (DHbT)', which is the time-derivative of total-hemoglobin concentration change that reflects the changes of cerebral blood volume and CBF. Although the absolute levels and the variations of systolic and diastolic BPs and mean arterial pressure showed no significant difference between the two groups, the proposed model showed a distinct difference in slope variation and response time of DHbT between the subjects with frequent symptom of orthostatic intolerance and the healthy control subjects. Thus, these results clearly demonstrate the feasibility of using CW-NIRS devices as a CA performance assessment tool.

Plastic straw: future of high-speed signaling.

The ever-increasing demand for bandwidth triggered by mobile and video Internet traffic requires advanced interconnect solutions satisfying functional and economic constraints. A new interconnect called E-TUBE is proposed as a cost-and-power-effective all-electrical-domain wideband waveguide solution for high-speed high-volume short-reach communication links. The E-TUBE achieves an unprecedented level of performance in terms of bandwidth-per-carrier frequency, power, and density without requiring a precision manufacturing process unlike conventional optical/waveguide solutions. The E-TUBE exhibits a frequency-independent loss-profile of 4 dB/m and has nearly 20-GHz bandwidth over the V band. A single-sideband signal transmission enabled by the inherent frequency response of the E-TUBE renders two-times data throughput without any physical overhead compared to conventional radio frequency communication technologies. This new interconnect scheme would be attractive to parties interested in high throughput links, including but not limited to, 100/400 Gbps chip-to-chip communications.

Efficient data extraction method for near-infrared spectroscopy (NIRS) systems with high spatial and temporal resolution.

An hardware-efficient method for the extraction of hemodynamic responses in near-infrared spectroscopy systems is proposed to increase the spatial and temporal resolution. The performance improvement is attributed to high signal-to-noise ratio receivers, a modulation scheme, and a multi-input-multi-output based data extraction algorithm. The proposed system shows more than twofold improvement in the figure of merit compared to conventional designs. Experimental results support the validity of the proposed system.