Search Results (524)

Background: Assessment of inflammatory activity in Crohn’s disease (CD) remains challenging. Bowel wall vascularization is an established marker of transmural inflammation and is typically evaluated using semiquantitative ultrasound scoring systems. In contrast, quantitative vascularization analysis is not yet widely used in clinical practice. To compare these approaches, this study evaluated semiquantitative and quantitative methods in the same patient cohort. Methods: This prospective single-center study included 50 patients with CD and sonographically detectable bowel wall thickening. Bowel wall vascularization was assessed using power Doppler (PD), color-coded superb microvascular imaging (cSMI) and monochrome mode superb microvascular imaging (mSMI). Video sequences were independently evaluated by three blinded readers using the Limberg classification. Quantitative vascularization was assessed using a vendor-derived vascular index and retrospective ImageJ analysis. Crohn’s Disease Activity Index (CDAI) and laboratory parameters were documented. Results: Interobserver agreement differed between imaging modalities. Krippendorff’s α values were 0.735 (PD), 0.655 (cSMI) and 0.527 (mSMI), indicating higher reliability for PD than for the SMI techniques. According to Fleiss’ κ (0.480 (PD), 0.376 (cSMI) and 0.367 (mSMI)), agreement was moderate for PD and fair for both SMI techniques. Complete concordance among all three readers was observed in 24 (PD), 18 (cSMI), and 22 (mSMI) patients, respectively. SMI-based techniques consistently resulted in higher Limberg grades compared to PD. Exploratory analyses showed strong correlations between different quantitative vascularization parameters (ρ up to 0.898, p < 0.001), but only moderate correlations with fecal calprotectin (FC) (ρ up to 0.389 with p = 0.017). Significant negative correlations were observed between vascular indices and body mass index (BMI) and skin-to-bowel distance (ρ up to −0.614, p < 0.001). The same trend was observed in the semiquantitative Limberg classification. Conclusions: Semiquantitative assessment of bowel wall vascularization seems to be limited by interobserver variability and Doppler technique, with SMI yielding higher Limberg grades than conventional Doppler. Standardized quantitative approaches may improve objectivity, but their reproducibility requires further validation. Patient-related factors should be considered when interpreting vascularization findings. Full article

Laboratory experiments were conducted to investigate the effects of the relative depth ratio, $D_r$, on flow in an asymmetric compound channel with a partially vegetated floodplain. Five cases covering $D_r=0.15-0.52$ were examined. Partial-width vegetation produced two lateral shear layers: the main-channel/floodplain (MCFP) layer and the non-vegetated/vegetated-floodplain (NVV) layer. As $D_r$ increased, streamwise velocity and discharge were redistributed from the main channel toward the floodplain: the main-channel discharge fraction decreased from 83.7% to 56.6%, while the combined floodplain fraction increased from 16.31% to 43.33%. The dimensionless shear parameters ${\lambda }_{MCFP}$ and ${\lambda }_{NVV}$ decreased from 0.584 to 0.064 and from 0.741 to 0.316, respectively, with ${\lambda }_{NVV}>{\lambda }_{MCFP}$ in all cases. The maximum local Reynolds shear stress occurred near the NVV interface. For the four cases measured using an acoustic Doppler velocimeter (ADV), mean transverse advection dominated the total depth-averaged transverse momentum exchange, and its case-wise maximum magnitude exceeded those of the Reynolds-stress and dispersive contributions by factors of 71.4–356.3 and 74.2–556.7, respectively. Spectral analysis indicated that large-scale coherent motions over the floodplain were strongest under shallow-flow conditions and weakened as $D_r$ increased. These findings show that $D_r$ regulates the relative roles of the two shear layers. Full article

Subclinical atherosclerosis (SCA) has been associated with lung function in many populations. Accordingly, those factors involved in respiratory health may contribute to the mechanisms linking pulmonary and cardiovascular disorders. Since the airway microbiome plays a key role in respiratory pathophysiology, microbial abundance and diversity in the upper airway may be associated with SCA risk. This study aimed to assess the association of upper airway microbiome abundance and diversity with SCA risk. A nested case–control study was carried out among adults from the Southern Caribbean. SCA was defined by carotid Doppler ultrasound as a carotid intima-media thickness ≥ 0.8 mm or the presence of carotid plaque. Oropharyngeal mucosal samples were collected under fasting conditions, and the V3-V4 region of the 16SRNA gene was sequenced. Differences in genus-level abundance were assessed using Microbiome Multivariable Association with Linear Models 2 (MaAsLin2). Alpha-diversity indices were compared through Wilcoxon tests. Principal coordinates analysis (PCoA) and Permutational Multivariate Analysis of Variance (PERMANOVA), adjusted for age, body mass index, and smoking status, were performed to assess associations between Bray–Curtis distances and SCA. MaAsLin2 was also applied to determine predicted metabolic pathway enrichment. A total of 40 cases and 40 controls were analyzed. The oropharyngeal microbiomes composition was dominated by three genera: Prevotella (cases: 26.0%; controls: 29.8%), Veillonella (cases: 16.3%; controls: 13.7%) and Fusobacterium (cases: 7.5%; controls: 8.0%). Significant differences in relative abundance were found for Streptococcus, Aureimonas, Mogibaecterium, Candidatus Saccharimonas, Pseudomonas, Segatella, Stomatobaculum, Oribacterium and Lachnoanaerobaculum, with lower abundance in cases for all these genera. Alpha-diversity was lower in cases than in controls, as reflected by the Shannon index (cases: 5.95 IQR [4.87; 6.35] vs. controls: 6.49 IQR [6.29; 6.75], p < 0.001), Simpson index (cases: 0.994, IQR [0.989; 0.996] vs. controls: 0.997 IQR [0.997; 0.998], p < 0.001) and Chao1 richness (cases: 1076.2 IQR [345.2; 1473.4] vs. controls: 1136.1, IQR [841.1; 1635.3], p = 0.04) were compared. In adjusted-PERMANOVA, 8.2% of microbiome variations were associated with SCA (pseudo-F = 7.49, R² = 0.082, p < 0.001), although this finding may have been influenced by intra-group dispersion among cases (PERMDISP: pseudo-F = 5.62, p = 0.018; Tukey’s HSD test: mean difference = −0.071, 95% CI [−0.118, −0.025], p = 0.003) Predicted enrichment of phenylalanine metabolism and indole alkaloid biosynthesis was higher in cases. In conclusion, these exploratory analyses suggest that reduced oropharyngeal microbiome diversity is associated with SCA. Further studies are warranted to clarify the role of the airway microbiome on cardiovascular outcomes. Full article

The renal resistive index (RRI) is a Doppler-derived parameter influenced by intrarenal hemodynamics, vascular compliance, pulsatile load, and systemic cardiovascular factors. In outpatient nephrology practice, RRI may provide adjunctive hemodynamic and prognostic information when interpreted together with kidney morphology, estimated glomerular filtration rate, proteinuria, blood pressure, heart rate, rhythm, and cardiovascular context. This protocol aims to standardize duplex Doppler acquisition, calculation, interpretation, and reporting of RRI in outpatient adults with native-kidney chronic kidney disease (CKD). The protocol defines patient eligibility and preparation, same-visit clinical data collection, grayscale kidney assessment, color Doppler localization of intrarenal arteries, pulsed-wave Doppler settings, bilateral upper-, middle-, and lower-pole sampling, waveform validity criteria, RRI calculation rules, image archiving, and structured reporting. Technical pitfalls and hemodynamic confounders are incorporated into the workflow to support reproducibility and serial comparability. The expected output is a standardized RRI report including kidney-specific and bilateral mean RRI values when minimum validity criteria are met, the number and location of valid sampling sites, grayscale morphologic findings, same-visit hemodynamic context, relevant technical limitations, and interpretive caveats. The protocol is designed to reduce acquisition variability and improve the consistency of RRI documentation in outpatient CKD practice. RRI should not be interpreted as a stand-alone diagnostic test or direct surrogate of renal vascular resistance. A standardized acquisition and reporting protocol may improve reproducibility and allow RRI to be used more appropriately as an adjunctive hemodynamic and prognostic marker in adults with non-dialysis-dependent CKD. Full article

This study aimed to determine the action of a single dose of human chorionic gonadotropin (hCG) on follicular dynamics, CL functionality, ovarian (OV.A) and uterine arteries (MUA) blood flow, hormones (estradiol [E2] and luteinizing hormone [LH]), nitric oxide (NO), and vascular endothelial growth factor (VEGF) levels in Thoroughbred mares. Animals were subjected to ultrasonography scanning, when the dominant follicle (F1) reached 35 mm in diameter, mares were injected with hCG (hCG group; n = 7) at hour 0, while others were injected with saline (control; n = 7). The examination was performed a those points at hours −24 h, −12 h, 0 h, 12 h, 24 h, 36 h, 48 h, 72 h, and 96 h. Blood sampling, ultrasound scanning, hormone assaying, and statistical analysis were performed. F1 was ruptured at 12 h after injection compared to 24 h in the control, with an elevation in its diameter (p ≤ 0.05) and a colored area surrounding F1. The amount of color Doppler area around CL and its diameter were increased (p ≤ 0.05) at 24 and 48 h after injection with an increase (p ≤ 0.05) in the ipsilateral uterine horn colored area from 6 to 36 h after injection. OV.A and MUA Doppler velocity parameters were elevated (p ≤ 0.05) at 24 h. Both NO and VEGF levels were elevated at 24 h after injection, with the elevation (p ≤ 0.05) of E2 occurring only before injection and then declining. hCG and LH levels were increased after injection at 12 and 24 h, respectively, with an interaction (p ≤ 0.05) effect. hCG may speed up and hasten the ovulation process by elevating follicular color amount and CL morphometry via elevating ovarian flow and uterine body total coloration via elevating uterine blood flow (declining Doppler indices) in mares. Full article

Resonant mass sensors based on micro/nanoelectromechanical systems (MEMS/NEMS) offer a promising approach for label-free gravimetric detection. However, practical applications often require not only high sensitivity but also improved loading repeatability and reduced dependence on mass loading position. In this work, a suspended resonant mass sensor based on a 10 nm-thick Hf_0.5Zr_0.5O₂ (HZO) piezoelectric film is proposed. A central silicon loading platform is introduced to provide a mechanically robust and spatially uniform sensing region. A Kirchhoff plate model incorporating residual stress is established to analyze the effects of residual stress and platform geometry on the resonant characteristics. The device is fabricated by combining SOI micromachining with wet transfer of the ultrathin HZO film. Laser Doppler vibrometry measurements show a first-order resonant frequency of 1.303 MHz and a quality factor of 342, corresponding to an extracted residual stress of approximately 1.319 GPa. Finite element simulations calibrated by experimental parameters indicate a uniform first-mode displacement distribution and a linear frequency response to added mass from 0 to 1 ng. The obtained mass sensitivities are 150.7 Hz/pg and 166.8 Hz/pg from finite element and analytical models, respectively. The proposed structure provides a feasible route toward repeatable pg-level resonant mass sensing based on ultrathin piezoelectric films. Full article

This paper proposes a micro-Doppler flash detection framework for hovering unmanned aerial vehicle (UAV) detection with linear frequency modulated continuous wave (LFMCW) radar under the dual constraints of strong ground clutter and severe thermal noise conditions. In such scenarios, conventional methods fail not only due to the spectral overlap between hovering targets and clutter but also because of the visual disappearance of micro-Doppler features under heavy noise. The framework consists of three sequential modules. A prior-template orthogonal projection (PTOP) module suppresses clutter via a single-step orthogonal projection, preserving the micro-Doppler flash signature without distortion while approximately maintaining the Gaussian noise statistics required for subsequent detection. A flash power spectrum construction module then collapses the periodic blade flash energy onto a sharp spectral peak in a one-dimensional (1D) power spectrum via Gabor transform, power projection, and fast Fourier transform (FFT). A cell-averaging constant false alarm rate (CA-CFAR) detection module with an analytically derived threshold factor finally renders a reliable detection decision. Simulations under a signal-to-clutter ratio (SCR) of $-21$ dB and signal-to-noise ratio (SNR) of $-23$ dB confirm that the proposed framework achieves reliable detection even when the micro-Doppler flash signatures are visually obscured by residual noise in the time–frequency domain. Parametric SNR sweep curves and a two-dimensional (2D) SCR–SNR detection-probability heatmap under a non-stationary clutter model further quantify the practical performance boundaries of the framework. By transforming these concealed periodic features into a sharp spectral peak, the framework provides robust detection performance where conventional range-Doppler and moving target indication (MTI)-based methods both exhibit severe performance degradation. Full article

Terrain-aided navigation (TAN) enables autonomous positioning through fusing prior terrain databases with real-time sensor measurements in GNSS-denied environments. Typical factors, including wide beam width and terrain elevation variations, introduce inaccuracies in elevation measurements, degrading the performance of classical elevation-based TAN methods. The SAR altimeter operates in nadir-looking mode to acquire range–Doppler projection images with inherent cross-track ambiguity for positioning based on image information, yet its accuracy is limited by single-feature and fixed-grid approaches. In this paper, we introduce an adaptive positioning framework for the SAR altimeter that combines XGBoost-based multi-feature fusion with Bayesian particle filtering. First, a fast DDM template generation algorithm is employed to improve computational efficiency. Then, an ensemble learning framework integrating complementary similarity features is introduced to achieve robust single-frame matching. Additionally, a Bayesian filtering-based dynamic grid construction method is developed to concentrate particles in high-probability regions, eliminating boundary truncation errors inherent to fixed approaches. The proposed method’s primary advantage is the reliable three-dimensional localization under extreme radar configurations, such as wide beam width and high-altitude maneuvering platforms. Experimental results based on both simulated and real data validate the method, demonstrating superior positioning performance under wide-beam conditions. Full article

Shear wave elastography (SWE) is an increasingly investigated ultrasound-based technique in musculoskeletal imaging that provides quantitative information on tissue stiffness and biomechanical properties. This narrative review aims to summarize the basic principles, technical considerations, current clinical applications, limitations, and future perspectives of SWE in musculoskeletal imaging. Unlike conventional grayscale and Doppler ultrasonography, which mainly assess morphology and vascularity, SWE may provide additional functional information in major musculoskeletal tissues, including tendons and ligaments, skeletal muscles, peripheral nerves, fibrocartilaginous structures, plantar fascia, and selected soft tissue lesions. Current evidence suggests potential roles for SWE in detecting early biomechanical alterations, assessing disease severity, differentiating symptomatic from asymptomatic tissues, and monitoring response to treatment or rehabilitation. However, musculoskeletal tissues are anisotropic, viscoelastic, and position-dependent; as a result, SWE measurements are influenced by acquisition-related factors, tissue biomechanics, positioning and loading conditions, region of interest (ROI) placement, tissue depth, and device-related variability. For this reason, SWE findings should not be interpreted as standalone diagnostic criteria but should be considered together with clinical findings, conventional ultrasonography, MRI, electrophysiology, histopathology, and patient-centered outcomes when appropriate. This review highlights the need for tissue-specific measurement protocols, standardized reporting, normative reference data, inter-vendor harmonization, and longitudinal validation against clinically meaningful outcomes before SWE can be more reliably integrated into routine musculoskeletal imaging and rehabilitation practice. Full article

This paper targets the air-to-ground (A2G) data backhaul scenario of UAVs and proposes a communication system based on coherent optical zero-padding orthogonal frequency division multiplexing (CO-ZP-OFDM), which unifies atmospheric turbulence scintillation, pointing errors, and Doppler frequency shift into a composite channel model. The system employs the Gamma-Gamma (GG) distribution to describe turbulence-induced intensity fluctuations, a Gaussian beam truncation model to characterize pointing errors, and a dual-pilot method to estimate and compensate the Doppler frequency offset. Furthermore, on a polarization-time-frequency (PTF) three-dimensional orthogonal grid pilot structure, we derive theoretical mean square error (MSE) expressions for the zero-forcing (ZF) and minimum mean square error (MMSE) estimators, and analyze their MSE characteristics under the proposed pilot model. Simulation results show that, under moderate turbulence, the shrinkage factor of the MMSE estimator yields only about $0.4$ dB MSE reduction over ZF at $\mathrm{SNR}=10$ dB, whereas the full receiver pipeline that combines coherence-bandwidth pilot averaging with the MMSE and maximum ratio combining (MRC) equalizer reduces the empirical MSE by approximately 15 dB. The bit error rate (BER) performance tests indicate that, under turbulence-free conditions with ideal channel estimation, the system can reduce the BER below ${10}^{-4}$ at an SNR of approximately 12 dB. Under strong turbulence conditions with MMSE channel estimation, the SNR cost required to achieve a BER of ${10}^{-3}$ is approximately 18 dB, which corresponds to a 3 to 5 dB BER gain over the ZF baseline at the same SNR. Further simulation analysis shows that the average pointing loss is highly sensitive to the angular jitter at the 1 km link distance: an angular jitter of 1 mrad incurs about 18 dB of loss, and a sub-mrad pointing stability (i.e., ${\sigma }_{\mathrm{jit}}<0.062$ mrad) is required to keep the average pointing loss below 1 dB. Full article

This paper investigates the viability of utilizing Fused Deposition Modeling (FDM) for the fabrication and follow-up testing of a hemispherical resonator (HR). This form of resonator has several significant applications, including the design of vibratory gyroscopes. While traditional high-precision resonators for this application rely on expensive fused-silica fabrication, this study proposes a macro-scale approach using Polylactic Acid (PLA) to enable accessible lab-scale experimentation. The specimens, featuring a unique central-hole mounting configuration, were designed in SolidWorks and analyzed via finite element methods to establish the modal hierarchy. Experimental Modal Analysis (EMA) was conducted using a Laser Doppler Vibrometer (LDV) to acquire vibration signals, which were then analyzed in NVGate, MATLAB, and MEscope to extract natural frequencies and quality factor. Results for a lab-scale HR specimen identified the n = 2 wine-glass mode with a deviation from theoretical natural frequency predictions largely attributed to inherent defects in the fabrication process. Furthermore, a frequency split of 2.15 Hz was observed due to the inherent asymmetries and mass imbalances of the fabrication method. The quality factor was evaluated via the ring-down method and validated using the half-power bandwidth (HPBW) technique. This work demonstrates that 3D-printed resonators serve as an effective, low-cost platform for isolating modal behaviors and optimizing geometric parameters before advancing to micro-scale fabrication. Full article

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease characterized by poor prognosis and accumulating evidence of systemic vascular involvement. Although cardiovascular comorbidities are recognized in IPF, the presence and extent of subclinical atherosclerosis are yet to be fully characterized. This study determined whether patients with IPF exhibit increased carotid intima–media thickness (CIMT) and altered atherogenic indices compared with healthy controls. Methods: This retrospective case–control study enrolled 117 patients with IPF diagnosed based on international guidelines and 104 age- and sex-matched healthy controls. All participants underwent comprehensive pulmonary function testing, the 6-min walk test (6MWT), laboratory evaluation (including lipid profiles), and bilateral carotid Doppler ultrasonography for CIMT measurement. Atherogenic indices, including the atherogenic coefficient, cholesterol ratio risk (CRR), and atherogenic index, were calculated. Dyspnea severity was evaluated using the visual analog scale (VAS). Results: Patients with IPF exhibited significantly higher CIMT (0.78 ± 0.12 mm vs. 0.68 ± 0.10 mm, p < 0.001) and CRR (4.12 ± 1.23 vs. 3.45 ± 0.98, p < 0.001) compared with controls. After adjustment for age, sex, cumulative smoking exposure expressed as pack-years, BMI, and controlled hypertension, IPF status remained independently associated with higher CIMT (adjusted β = 0.086 mm, 95% CI: 0.057–0.115; p < 0.001) and CRR (adjusted β = 0.482, 95% CI: 0.191–0.773; p = 0.001). Furthermore, patients with IPF had significantly lower HDL cholesterol levels and higher VLDL cholesterol levels. CIMT correlated negatively with 6MWT distance (r = −0.312, p = 0.001) and positively with VAS dyspnea scores (r = 0.287, p = 0.002). Conclusions: Patients with IPF showed higher CIMT and more unfavorable atherogenic profiles than healthy controls, and these associations persisted after adjustment for major vascular risk factors. The observed relationships between CIMT, functional capacity, and dyspnea severity suggest a potential association between IPF and subclinical cardiovascular involvement. Prospective studies are warranted to clarify the clinical relevance and prognostic implications of these findings. Full article

Background/Objectives: This study evaluates the prognostic utility of placental insufficiency biomarkers in late-onset fetal growth restriction occurring after 32 weeks of gestation. These markers were assessed both independently and in conjunction with ultrasound and Doppler indices to predict adverse perinatal outcomes. Given the clinical integration of maternal angiogenic factor assessment, it is imperative to determine whether these markers—specifically the sFlt-1/PlGF ratio—can effectively mitigate fetal and neonatal morbidity and mortality. Methods: This review is registered with PROSPERO and encompasses the literature from the last decade. The present analysis incorporated prospective observational cohort studies. Four comprehensive databases were queried, resulting in the evaluation of fifty-one relevant records. Thirty-six full-text articles were assessed for eligibility, resulting in the inclusion of six relevant manuscripts. The total sample size was 14.499 patients. Detection rates for growth restricted fetuses demonstrated significant variability, ranging from 15% to 88.5%. Conclusions: The clinical utility of angiogenic biomarkers for the prediction of fetal growth restriction remains unresolved; moreover, the empirical evidence synthesized within this review exhibits a significant degree of heterogeneity. Full article

Background/Objectives: Atherosclerosis is a multifaceted inflammatory condition closely linked to immunonutritional status. The C-reactive protein–albumin–lymphocyte (CALLY) index is a composite marker of immunonutrition. We assessed the relationship between this index, age, and carotid stenosis in individuals undergoing carotid Doppler ultrasonography. Methods: Individuals who underwent routine carotid Doppler ultrasonography were retrospectively analyzed. Carotid stenosis was categorized by severity, and bilateral intima–media thickness was recorded. The composite index integrating C-reactive protein, albumin, and lymphocyte parameters was derived from laboratory parameters. Traditional cardiovascular risk factors, including hypertension, diabetes mellitus, hyperlipidemia, and smoking status, were also recorded and incorporated into multivariable analyses. Sex-related differences were additionally evaluated using sex-stratified correlation analyses. Results: Among 1516 patients, 895 (59.1%) were younger than 65 years and 621 (40.9%) were aged 65 years and above. Carotid artery stenosis and intima–media thickness were significantly higher in individuals aged 65 years and above. The mean index value was significantly lower in the older group (4.0 versus 8.3; p < 0.001). Hypertension, diabetes mellitus, and hyperlipidemia were significantly more prevalent in patients with carotid stenosis (p < 0.001 for all), whereas smoking was not associated (p > 0.05). Male sex was independently associated with carotid stenosis, and sex-stratified analyses demonstrated similar inverse associations between age and CALLY index values in both sexes. In multivariable analysis, lower index values were independently associated with carotid stenosis and carotid intima–media thickness in both age groups. In the overall cohort, the index demonstrated moderate discriminatory performance (area under the curve = 0.724). Similar moderate performance was observed in the <65 (AUC = 0.681) and ≥65 (AUC = 0.685) subgroups. Conclusions: The CALLY index was independently associated with carotid stenosis and CIMT after adjustment for traditional cardiovascular risk factors. Although effect sizes were comparable between age groups, CALLY index levels were lower in older individuals. These findings suggest that the CALLY index may provide complementary information in the assessment of carotid atherosclerosis, particularly in elderly populations. However, given the retrospective cross-sectional design and moderate discriminatory performance, it should not be interpreted as a standalone, causal, or disease-specific marker. Full article

Conductive intracardiac communication (CIC) is one of the most innovative and promising communication technologies in multi-point cardiac pacing schemes that utilize the heart as the transmission channel in recent years. Current research predominantly focuses on static channel characteristics. Although some studies have explored dynamic responses, they are largely confined to basic amplitude–frequency and amplitude–time behaviors, lacking in-depth analysis of underlying dynamic mechanisms such as path loss, shadowing, multipath, and Doppler effects. Designing CIC systems solely on the basis of static properties can result in inaccurate channel estimation, distorted channel state information (CSI), and elevated bit error rate (BER). To solve the problems of dynamic channel measurement and modeling, this paper for the first time proposes a dynamic channel modeling method for CIC based on sinusoidal response and impulse response. Firstly, we develop a physical simulation and miniaturized measurement setup to measure the dynamic cardiac channel, and analyze the amplitude–frequency characteristics and amplitude–time characteristics. The influence of factors such as instrument differences, heart rate, flow rate, and motion artifacts is also discussed. Secondly, we systematically analyze the path loss, shadowing effect, multipath effect, and Doppler effect of the CIC channel. Combined with the dynamic channel characteristics and parameters, we propose a composite fading dynamic channel model and analyze the BER performance of baseband signal transmission and On–Off Keying (OOK) modulation systems. We conclude that (1) the CIC channel exhibits capacitive characteristics. Fixed electrodes can effectively suppress motion artifacts. (2) The dynamic channel gain of CIC varies periodically with the heartbeat, and the fluctuation range of the signal is less than 1–2 dB. (3) The dynamic CIC channel presents extremely weak shadow fading, no significant multipath, and no measurable Doppler characteristics, belonging to an extremely slow-fading channel. This work provides effective dynamic channel measurement approaches and a parameter basis for the transceiver design of CIC and a reliable model for the simulation of CIC systems. Full article