Attenuation Measurements Research Articles

Automated Integration of AI Results into Radiology Reports Using Common Data Elements.

Integration of artificial intelligence (AI) into radiology practice can create opportunities to improve diagnostic accuracy, workflow efficiency, and patient outcomes. Integration demands the ability to seamlessly incorporate AI-derived measurements into radiology reports. Common data elements (CDEs) define standardized, interoperable units of information. This article describes the application of CDEs as a standardized framework to embed AI-derived results into radiology reports. The authors defined a set of CDEs for measurements of the volume and attenuation of the liver and spleen. An AI system segmented the liver and spleen on non-contrast CT images of the abdomen and pelvis, and it recorded their measurements as CDEs using the Digital Imaging and Communications in Medicine Structured Reporting (DICOM-SR) framework to express the corresponding labels and values. The AI system successfully segmented the liver and spleen in non-contrast CT images and generated measurements of organ volume and attenuation. Automated systems extracted corresponding CDE labels and values from the AI-generated data, incorporated CDE values into the radiology report, and transmitted the generated image series to the Picture Archiving and Communication System (PACS) for storage and display. This study demonstrates the use of radiology CDEs in clinical practice to record and transfer AI-generated data. This approach can improve communication among radiologists and referring providers, harmonize data to enable large-scale research efforts, and enhance the performance of decision support systems. CDEs ensure consistency, interoperability, and clarity in reporting AI findings across diverse healthcare systems.

Achieving High-Precision Attenuation Coefficient Measurement in Optical Coherence Tomography.

In this study, we aim to validate the analytical Cramer-Rao lower bound (CRLB) equation for determining attenuation coefficients using a 1310 nm Optical Coherence Tomography (OCT) system. Our experimental results successfully confirm the validity of the equation, achieving unprecedented precision with a standard deviation below 0.01 mm-1 for intralipid samples. Furthermore, we introduce a systematic framework for attaining high precision in OCT attenuation measurements.

Site-response high-frequency frontiers and the added value of site-specific earthquake record-based measurements of velocity and attenuation

One-dimensional (1D) ground-response analysis based on 1D velocity profiles and generic relationships between damping and velocity is frequently employed under the assumption that it can provide a reliable assessment of site effects. According to this hypothesis, epistemic uncertainty in site response primarily stems from inaccurately determined soil parameters. As shown by the recent development of ground-motion models in the Fourier domain, the underlying site-to-site variability of site response rises sharply at intermediate to high frequencies (>3 Hz), and this increase cannot be compensated for when relying on coarse velocity profiles and generic relationships between damping and velocity. In order to solve this high-frequency frontier in site response, we invert the spectral ratio of the horizontal-to-vertical components of strong motions based on the diffuse field concept for obtaining refined 1D velocity profiles and site-specific damping profiles. These updated equivalent structures of both velocity and damping significantly improve the performance of 1D ground-response analyses. This effect is particularly strong at intermediate frequencies (3–10 Hz), where both the deep sedimentary structure and the damping profile above the seismological bedrock have a strong influence on site response. While the use of refined 1D velocity and generic damping profiles for test sites of the Japanese KiK-net already provides a reduction of the intermediate-to-high-frequency residual and corrected site-to-site variability (and then an increase in the precision of predictions), the inclusion of site-specific damping allows this value almost to be halved. The results show that many sites are indeed too complex to be modeled by classical 1D ground-response analysis relying on generic damping relationships, while only site-specific record-based models allow a significant reduction in the bias.

Comparison Between Attenuation Measurement and the Controlled Attenuation Parameter for the Assessment of Hepatic Steatosis Based on MRI Images.

This study prospectively compared the diagnostic accuracies of the improved Attenuation Measurement (iATT) algorithm and the Controlled Attenuation Parameter (CAP) and assessed the interchangeability of iATT with magnetic resonance imaging-derived proton density fat fraction (MRI-derived PDFF). Patients with chronic liver disease were prospectively enrolled and underwent iATT, CAP and MRI-derived PDFF measurements for hepatic steatosis evaluation. According to MRI-derived PDFF values, steatosis grades were categorised as steatosis (S)0 (< 5.2%), S1 (≥ 5.2%, < 11.3%), S2 (≥ 11.3%, < 17.1%) and S3 (≥ 17.1%). Correlation coefficients (CCs) were determined, diagnostic performances were compared by the area under the receiver operating characteristic curve (AUROC) and agreement was evaluated using the calculated percentage error (PE) and expected limit of agreement (LOA). A total of 414 patients (median age 64 years, 203 females) were evaluated. The CC between iATT and MRI-derived PDFF was 0.727 (95% confidence interval [CI] 0.678-0.770), which was higher than that between CAP and MRI-derived PDFF at 0.615 (95% CI 0.551-0.672) (p < 0.001). The AUROCs of iATT for ≥ S1, ≥ S2 and ≥ S3 were 0.901 (95% CI 0.870-0.931), 0.878 (95% CI 0.846-0.910) and 0.839 (95% CI 0.794-0.883), respectively. The diagnostic performances of iATT for ≥ S1 and ≥ S2 showed significantly higher AUROCs than those of CAP (p < 0.001, p = 0.036, respectively). The calculated PE and the expected LOA for CAP and iATT were 38.94% and 22.66% and 32.94% and 30.03%, respectively. iATT was superior to CAP and comparable to MRI-derived PDFF in assessing hepatic steatosis. This study was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN000047411).

Measurement of Lumbar Vertebral Body Attenuation at PET-CT Is A Reliable Method of Diagnosing Osteoporosis.

Measurement of Lumbar Vertebral Body Attenuation at PET-CT Is A Reliable Method of Diagnosing Osteoporosis.

Underwater sound propagation over a layered seabed with weak shear rigiditya).

The shear wave speed is often small compared to the compressional wave speed in the top part of the seabed, where acoustic normal modes penetrate. In sediments with weak but finite shear rigidity, the strongest conversion from compressional to shear waves occurs at interfaces within the sediment. Shear wave generation at such interfaces and interference within sediment layers lead to first-order perturbations in the normal mode phase speed and contributions to sound attenuation, which vary rapidly with frequency. Weak shear rigidity is shown to lead to unexpectedly strong mode group speed perturbations that retain finite magnitudes for very small shear speeds in range-independent waveguides. Variation of the waveguide parameters with range affects shear-induced attenuation and mode travel time perturbations in a different manner, depending on whether shear wave interference conditions vary appreciably along the propagation path. In horizontally inhomogeneous ocean, weak shear magnifies the horizontal refraction of adiabatic normal modes due to sloping intra-sediment interfaces. In contrast to normal modes, attenuation of lateral waves with range is insensitive to weak shear. Concurrent measurements of normal mode and lateral wave attenuation can be potentially used to identify and separate the contributions of dissipation and shear waves into observed sound attenuation.

Experimental investigation on the effect of concentration on the resonance frequency of lipid coated ultrasonically excited microbubbles

This study presents an experimental investigation of the influence of MB concentration on the resonance frequency of lipid-coated microbubbles (MBs). Expanding on theoretical models and numerical simulations from previous research, this work experimentally investigates the effect of MB size on the rate of resonance frequency increase with concentration, a phenomenon observed across MBs with two different lipid compositions: propylene glycol (PG) and propylene glycol and glycerol (PGG). Employing a custom-designed ultrasound attenuation measurement setup, we measured the frequency-dependent attenuation of MBs, isolating MBs based on size to generate distinct monodisperse sub-populations for analysis. The resonance frequency of MBs was determined by identifying the attenuation peak in the broadband attenuation ultrasound attenuation measurements. Our experimental findings confirm that larger MBs (≈2.1μm) demonstrate a more significant shift in resonance frequency (≈ 5 MHz, ≈ 40%) as a function of MB concentration. In contrast, smaller MBs (≈1.3μm) show a minor shift in the resonant frequency (≈ 1.8MHz, ≈ 8%), underlining the importance of size in determining acoustic behavior compared to changes in the lipid shell properties. Additionally, we observed that resonance frequency increase with concentration reaching a saturation point at higher concentrations. This plateau occurs at higher concentrations for larger MBs (≈2.1μm), while smaller MBs (≈1.6μm and ≈1.3μm) reach this saturation point at lower concentrations. Furthermore, the study highlights the small effect of bubble-bubble interactions on the resonance frequency of MB populations, particularly at lower MB concentrations and for smaller MBs. This insight is important for applications utilizing MB clusters, such as contrast-enhanced ultrasound imaging and MB-mediated therapies. While both size and lipid shell composition influence resonance frequency, MB size has a more significant effect. In conclusion, our findings affirm the need to consider both MB size and concentration when utilizing MBs for clinical and industrial ultrasonic applications.

Rapid prediction model of terahertz transmission in hypersonic plasma sheath under different flight speeds for different vehicle types

Abstract This work clarifies the systematic relationship and difference mechanism between flight speed, plasma sheath and terahertz transmission under different vehicle types by joint simulation model of hypersonic plasma flow and improved scattering matrix method. Significant differences in plasma sheath and terahertz transmission characteristics are observed in different vehicle types. Radio Attenuation Measurement C (RAM C) vehicle has a larger collision frequency and sheath thickness, resulting in higher terahertz attenuation than Hypersonic International Flight Research Experimentation (HIFiRE) vehicle. With the increase of flight speed, electron density, collision frequency and terahertz attenuation of the two different types of vehicles all show a significant increase, and the sheath thickness shows an opposite trend. However, the impact of flight speed on HIFiRE vehicle is much smaller than that on RAM C vehicle, which means that flight parameters have higher control accuracy for RAM C vehicle. On this basis, the systematic relationship between plasma sheath distribution and flight speed is further determined, and a rapid prediction model for terahertz transmission attenuation of different types of vehicle is developed based on a large amount of plasma sheath data. The rapid prediction model greatly reduces the calculation time and resources compared with traditional numerical methods, and its related prediction coefficients show significant differences on different vehicle types.

Triglycerides to apolipoprotein A1 ratio: an effective insulin resistance-associated index in identifying metabolic dysfunction-associated fatty liver disease in type 2 diabetes mellitus

BackgroundThe triglycerides to Apolipoprotein A1 ratio (TG/APOA1) holds promise to be a more valuable index of insulin resistance for the diagnosis of metabolic dysfunction-associated fatty liver disease (MAFLD) in type 2 diabetes mellitus (T2DM). This study aims to evaluate the correlation between TG/APOA1 and MAFLD, as well as compare the efficacy of TG/APOA1 with triglycerides to high-density lipoprotein cholesterol ratio (TG/HDL-c) and triglyceride-glucose (TyG) index in identifying MAFLD among individuals with T2DM.MethodThis study consecutively recruited 779 individuals with T2DM for the investigation. The unenhanced abdominal CT scans were conducted to measure CT liver-spleen attenuation measurement (CTL-S). The CTL-S less than 1.0 and without other liver comorbidities were considered to be MAFLD. The binomial logistic regression analysis and restricted cubic spines (RCS) were employed to evaluate the association between TG/APOA1 and MAFLD. The receiver operating characteristic (ROC) curve analysis was performed to compare the efficacy of TG/APOA1 with TG/HDL-c and TyG index identifying MAFLD.ResultsThe TG/APOA1 exhibited a substantial increase in the MAFLD group (P&amp;lt;0.05). Even after adjustments for potential confounding factors, TG/APOA1 exhibited significant associations with nonalcoholic fatty liver disease fibrosis score (β=0.266, P&amp;lt;0.001), fibrosis-4 index (β=0.123, P=0.029), aspartate aminotransferase-to-platelet ratio index (β=0.113, P=0.037), and CTL-S (β=-0.225, P&amp;lt;0.001). Meanwhile, TG/APOA1 contributed to an independent variable for MAFLD, the odds ratio with a 95% CI was 2.092 (1.840-2.380) in the total population, 2.123 (1.810-2.511) in men, and 2.162 (1.824-2.587) in women. Additionally, the results also revealed a nonlinear association between elevated TG/APOA1 and higher MAFLD risk according to the RCS analysis whether in the total population, men, or women (P for nonlinearity and overall &amp;lt;0.001). Furthermore, TG/APOA1 had higher AUC level compared to TG/HDL-c and TyG index in the total population (0.769 vs 0.742, P=0.025; 0.769 vs 0.694, P &amp;lt; 0.001), men (0.776 vs 0.744, P=0.044; 0.776 vs 0.709, P &amp;lt; 0.001), and women (0.762 vs 0.728, P=0.041; 0.762 vs 0.674, P &amp;lt; 0.001).ConclusionTG/APOA1 serves as an effective index of insulin resistance in identifying MAFLD, offering advantages in the screening of MAFLD in T2DM.

Design of a station for testing combustion products

The article presents an original test stand for the analysis of combustion products, utilizing spectrophotometric analysis to identify the material being burned. The authors conducted a theoretical analysis concerning spectrophotometric studies based on the use of the light attenuation parameter in various media and presented preliminary results from tests performed on the designed stand. The article includes a summary presentation of the results of light attenuation measurements and other parameters calculated from the obtained data. Additionally, they discussed potential methods and benefits of implementing this approach in Fire Alarm Systems (FAS), as a method to increase the effectiveness of FAS and the safety of emergency services.

Determination of Mass Attenuation Coefficient of Jute Reinforced Epoxy Resin Composite as Tissue Equivalent Phantom

Abstract The mass attenuation coefficient is a fundamental parameter in radiation physics and plays a pivotal role in understanding the interaction of ionizing radiation with matter. This study aims to determine mass attenuation coefficients of newly developed tissue equivalent phantom fabricated from jute fibres reinforced with epoxy resin and activated carbon as a filler. The composites were prepared based on four different filler levels (ranging from 0wt% to 5wt%). The produced phantoms are characterized in terms of half-value layer HVL (cm) relating to linear attenuation coefficient, μ (cm−1). The linear and mass attenuation coefficients for the composites with different wt% of filler were determined at three different kV settings of the X-ray generator, covering the lower energy range of normal diagnostic practice (50 kVp, 102 kVp and 109 kVp) and by using the half-value layer (HVL) method. Aluminum filters were used to determine the HVL values and subsequently calculated the attenuation coefficients. The value of attenuation coefficients of fabricated composite materials was contrasted with theoretical value through the utilization of XCOM software at the same energy levels. The results were in good agreement for all ranges of wt% composite. These findings not only have significant practical implications for radiation-related technologies and applications but also enhance material characterization techniques. Hence, the attenuation measurements conducted in this study validate the suitability of jute-reinforced epoxy resin, filled with activated carbon as a phantom material that mimics human tissue.

Prognostic value of gray–white matter ratio measured by brain MRI-based CT structures in comatose patients after cardiac arrest

BackgroundPost-cardiac arrest care advancements have improved resuscitation outcomes, but many survivors still face severe neurological deficits or death from brain injury. Herein, we propose a consistent prognosis prediction approach using magnetic resonance imaging (MRI) to analyze anatomical regions represented by the gray and white matter, and subsequently apply it on computed tomography (CT) to calculate the gray–white matter ratio (GWR). We compared this novel method with traditional measures to validate its ability to predict the prognosis of patients resuscitated after cardiac arrest. MethodsConducted retrospectively at two South Korean tertiary university hospitals from January 2018 to December 2022, the study included adult cardiac arrest survivors treated with therapeutic target temperature management. Patients underwent brain CT within 2 h and brain MRI within 3 days of return of spontaneous circulation. The outcome was the neurological status at discharge. Statistical analyses included receiver operating characteristic curve analysis and determining cutoff values to predict poor neurological outcomes. ResultsOverall, 51 of the 421 adult comatose cardiac arrest survivors examined met the inclusion criteria. Among these, 33 and 18 exhibited good and poor neurological outcomes, respectively. Demographic and cardiac arrest characteristics were compared between the two groups, revealing significant differences. Analyses of gray and white matter attenuation and GWR measurements highlighted significant differences between the good and poor outcome groups. ConclusionOur study introduces a novel method for measuring GWR using MRI-based brain CT, demonstrating superior prognostic accuracy in predicting neurological outcomes in patients with post-cardiac arrest syndrome compared to traditional methods.

Effect of Vessel Attenuation, VMI Level, and Reconstruction Kernel on Pericoronary Adipose Tissue Attenuation for EID CT and PCD CT: An Ex Vivo Porcine Heart Study.

BACKGROUND. Pericoronary adipose tissue (PCAT) attenuation and the fat attenuation index (FAI) may serve as markers of inflammation and the risk of adverse cardiac events. However, standardization of relevant CT acquisition and reconstruction parameters is lacking. OBJECTIVE. The purpose of this study was to investigate the influence of vessel attenuation, the virtual monoenergetic image (VMI) level, and the reconstruction kernel on PCAT attenuation and FAI by use of energy-integrating detector (EID) and photon-counting detector (PCD) CT systems in an ex vivo porcine heart model. METHODS. The right coronary artery (RCA) of a porcine heart was injected with saline or varying contrast medium dilutions to achieve vessel attenuation ranging from 0 to 1000 HU. After each injection, the heart was sequentially scanned by EID CT at 120 kVp and PCD CT at 140 kVp at a constant CTDIvol of 10 mGy. For EID CT, polychromatic images were reconstructed with a Qr40 kernel. For PCD CT, VMIs (obtained at 40-80 keV in 10-keV increments) were reconstructed with Qr40, Bv40, and Bv56 kernels. ROIs were placed to measure RCA and PCAT attenuation. FAI was determined using software; histogram analysis was performed to assess voxel attenuation in the volumes of interest for FAI calculation. RESULTS. Correlations were observed between attenuation in the RCA and attenuation in the adjacent PCAT (r = 0.3-1.0) and between vessel attenuation and the FAI (r = -0.9 to 1.0). For PCAT attenuation and the FAI, these associations became progressively weaker when progressively sharper kernels were used. For increasing vessel attenuation on EID CT and for increasing VMI level on PCD CT, FAI histograms showed right shifts in peak attenuation values; the percentage of histogram voxels that met the threshold range for inclusion in FAI calculation was 9-38% for EID CT and 6-39% for PCD CT at VMI levels of 70-80 keV. For PCD CT, use of sharper kernels was associated with left shifts in peak attenuation values and greater percentages of voxels within the threshold range for inclusion in FAI calculation. CONCLUSION. PCAT attenuation and the FAI are influenced by vessel lumen attenuation, the VMI level, and the reconstruction kernel. A minority of pericoronary voxels contribute to FAI measurements for polychromatic EID CT and for PCD CT at high VMI levels. CLINICAL IMPACT. These findings may help standardize acquisition and reconstruction parameters for PCAT attenuation and FAI measurements.

Fabrication and characterization of rubcrete-iron composite for mixed radiation shielding

Mixed radiation environments need unique shielding materials that can effectively attenuate photons and neutrons simultaneously. Most ordinary shielding materials can only shield one form of radiation effectively. In this work, a novel composite material was fabricated in our laboratories and characterized for photon and neutron shielding. Waste materials were used as partial substitutes for aggregates in concrete, which is a sustainable practice in the building industry at present. The main components of the composite material are iron filings, rubber, and concrete. Concrete samples were mixed with iron filings at varying percentages (0%, 10%, 20%, and 30%) and a fixed 5% crumb rubber content. The material’s photon and neutron shielding characteristics were evaluated through experimental and simulation methods. Gamma-ray attenuation measurements were experimentally carried out using a NaI(TI) spectrometer and a Cs-137 0.662 MeV energy source. In contrast, GEANT4, PHY-X/PSD, and NIST-XCOM codes were used to simulate photon and neutron cross-sections. The findings indicate that an increase in iron filings results in enhanced radiation attenuation, reflected by a higher linear attenuation coefficient (μ). The linear attenuation coefficient values range from (0.1590 ± 0.0004) to (0.2045 ± 0.0003) cm−1 for samples with no crumb rubber and from (0.1521 ± 0.0002) to (0.1920 ± 0.0004) cm−1 for samples with 5% crumb rubber. Half Value Layer (HVL) decreases with an increase in iron content and is slightly higher in samples with crumb rubber. The HVL results from simulations and measurements agree. This study optimizes the potential of concrete as a radiation-shielding material while promoting sustainable construction and environmental practices.

Effect of attack angle on the electromagnetic wave transmission characteristics in the hypersonic plasma sheath of a re-entry vehicle

The attack angle may greatly affect the hypersonic plasma sheaths around the re-entry vehicle, thereby affecting the transmission characteristics of electromagnetic (EM) waves in the sheaths. In this paper, we propose an integrated three-dimensional (3D) model with various attack angles and realistic flying conditions of radio attenuation measurement C-II (RAM C-II) re-entry tasks for analyzing the effect of the attack angle on the transmission characteristics of EM waves in the sheaths. It is shown that the electron density and collision frequency of the sheath on the windward side can be increased by an order of magnitude with the increase of the attack angle. Meanwhile, the thickness of the sheath on the leeward side is increased where the electron density and collision frequency are reduced. The EM waves are mainly reflected on the windward plasma sheath due to the cutoff effect, and the radio-frequency (RF) blackout is mitigated if the antenna is positioned on the leeward side. Thus, by planning the trajectory properly and installing the antenna accordingly during the re-entry, it is possible to provide an approach for mitigation of the RF blackout problem to an extent.

Effect of Connection Losses on Fiber To The Building (FTTB) Network Activation

The Fiber To The Building (FTTB) technology uses fiber optic cables for high-speed data transmission in high-rise office buildings. However, connection loss in fiber optic cables, especially during network activation, can significantly affect the overall performance and reliability of the FTTB network. This study investigates the effects of connection loss on total attenuation in FTTB networks before and after activation, using Passive Optical Network (PON) technology. Simulations were performed on three subscriber scenarios with different treatments of drop core cables (no connection, one connection, two connections) and patch cord cables of different lengths (3m, 5m, 10m), each with additional variations in the number of connections. Attenuation measurements were taken before and after network activation, showing that increasing cable length and splices leads to higher attenuation and reduced network performance. For example, customer 1 with no connections had the lowest attenuation before activation of 19.68 dB and after activation of 19.57 dB with signal quality (ping ONU 11 ms, ping OLT 9 ms, and ping Google 31 ms) while customer 3 with the most connections had attenuation values before activation of 20.92 dB and after activation of 20.87 dB with signal quality (ping ONU 29 ms, ping OLT 28 ms, and ping Google 70 ms). This research emphasises the importance of link management and the length of cable used to minimize attenuation and ensure optimal network performance.

Sensitivity analysis and uncertainty quantification for a three-dimensional rarefied ionized hypersonic flow

The “communications blackout” phenomenon has bothered the aerospace industry for several decades. However, the unsatisfying numerical methods and the rapidly changing inflow conditions make the estimation of electrons’ density inaccurate. To lay the first step for model calibration and the anti-blackout design, the Artificial Neural Networks and the direct simulation Monte Carlo (DSMC) method with the quantum-kinetic (Q-K) model are brought together to perform the global sensitivity analysis and uncertainty quantification. The three-dimensional RAM-C II (the second flight of the Radio Attenuation Measurement experiments) head flows are simulated considering aleatory uncertainties (inflow uncertainties) and epistemic uncertainties (reaction parameters uncertainties). Under the inflow condition of an 81 km atmosphere and a velocity of 7.8 km/s, aleatory uncertainties are found to be the dominant type of uncertainty for the number density of electrons, especially the freestream velocity, which means the accurate measurement of the vehicle’s velocity is much more critical than the calibration of the model. The importance ranking is listed, and the “Three rules” for finding the essential reactions are proposed. The probability that the real value is smaller than the nominal value considering both uncertainties is 27%–68%.

A New NDSA (Normalized Differential Spectral Attenuation) Measurement Campaign for Estimating Water Vapor Along a Radio Link

The Normalized Differential Spectral Attenuation (NDSA) technique was proposed years ago as an active method for measuring integrated water vapor (IWV) along a Ku/K-band radio link immersed (totally or partially) in the troposphere. The approach is of the active kind, as it relies on the transmission of a couple of sinusoidal signals, whose power is measured at the receiver, thus providing the differential attenuation measurements from which IWV estimates can be in turn derived. In 2018, a prototype instrument providing such differential attenuation measurements was completed and set up for a first measurement campaign aimed at demonstrating the NDSA method. By the end of June 2022, the instrument was profoundly modified and upgraded so that a second measurement campaign could be carried out from 1 August to 30 November 2022. The transmitter was placed on the top of Monte Gomito (44.1277°lat, 10.6434°lon, 1892 m a.s.l.) and the receiver on the roof of the Department of Information Engineering of the University of Florence (43.7985°lat, 11.2528°lon, 50 m a.s.l.). The resulting radio link length was 61.15 km. Four ground weather stations of the regional weather service were selected among those available. In this paper, we describe the upgraded instrument and present the outcomes of the new measurement campaign, whose purpose was mainly to compare the IWV estimates provided by the instrument with the ground sensor measurements of air temperature, air humidity, barometric pressure, and rainfall. In particular, we show that the temporal trends of the two IWV estimates are qualitatively consistent, and that the instrument is able to provide IWV estimates also in the presence of fog and rainfall. Conversely, a quantitative evaluation through comparison with IWV data from point weather station measurements appears challenging due to the significant spatial variability in temperature and relative humidity, even between couples of stations that are quite close to each other.

Study of the acoustic attenuation of 2D axisymmetric models of the human ear equipped with hearing protection

The ear is the organ responsible for auditory perception. Its role is to amplify, transmit, and convert an acoustic wave present in the environment into an electrical pulse that the brain can interpret via the auditory nerve. The objective of this study was to develop two axisymmetric 2D finite element models of the human ear to predict insertion loss when a porous earplug is introduced into the ear canal. In these models, the structure-acoustic interaction was resolved by finite element analysis. For a better representation, assumptions and boundary conditions (such as fixe boundary condition, spring-mass-damping boundary condition, etc...) are considered. The tympanic ring and the earplug are assumed to be fixed, and a load of what comes after the posterior part of the tympanic ring (the ossicular chain) has been replaced by an equivalent mechanical impedance mass-spring-damper system. The first model has a regular geometry, and the second model is obtained by reconstructing a 3D model. These two models were inspired by our previous work. For each model, the insertion loss (IL) is predicted and the results obtained are compared with those of the sound attenuation measurements of hearing protection performed in the laboratory.

Opportunistic Screening of Bone Fragility Using Computed Tomography.

Opportunistic screening uses existing imaging studies for additional diagnostic insights without imposing further burden on patients. We explore the potential of opportunistic computed tomography (CT) screening for osteoporosis, a condition affecting 500 million people globally and leading to significant health care costs and fragility fractures. Although dual-energy X-ray absorptiometry (DXA) remains the gold standard for diagnosing osteoporosis, > 50% of fractures occur in individuals not screened previously with DXA. With recent advancements in technology, CT has emerged as the most promising tool for opportunistic screening due to its wide use and the ability to provide quantitative measurements of bone attenuation, a surrogate of bone mineral density. This article discusses the technical considerations, calibration methods, and potential benefits of CT for osteoporosis screening. It also explores the role of automation, supervised and unsupervised, in streamlining the diagnostic process, improving accuracy, and potentially developing new biomarkers of bone health. The potential addition of radiomics and genomics is also highlighted, showcasing the synergy between genetic and imaging data for a more comprehensive understanding of osteoporosis pathophysiology and with it possible novel osteoporosis therapies. The future of opportunistic CT screening holds significant promise, with automation and advanced image processing ultimately enhancing patient care, reducing rates of osteoporotic fractures, and improving patient outcomes.