Search Results (198)

Knee rotational stability is crucial for anterior cruciate ligament (ACL) procedures, yet, current clinical assessments are subjective and lack precision. This study evaluates the accuracy and repeatability of the GATOR system, developed by PreciX Pte Ltd. and integrating ultrasound with inertial measurement units (IMUs), against a reference IMU (Xsens DOTS) for measuring knee flexion and rotation in six cadaveric specimens secured in an Oxford Knee Jig. Two experiments were conducted: (A) knee flexion from 0° to 120°, and (B) internal/external rotation at 0°, 30°, 60°, 90°, and 120° flexion. Analysis using Bland–Altman plots, root mean square error (RMSE: 3.93° for internal rotation, 6.90° for external rotation), mean biases, and paired t-tests (Bonferroni corrected) revealed that GATOR recorded lower peak flexion angles (91.49–114.65°) compared to the reference (110.31–118.49°). For rotation, internal rotation showed narrower limits of agreement than external rotation (biases: 1.91–6.88°). Over 60% of trials had errors < 5°, and 80% < 10°, indicating good agreement. Despite no isolated comparison of GATOR’s ultrasound component, findings suggest reduced soft tissue artifact due to bone-referenced sensor alignment. With optimal placement (10–15 cm from the knee center), GATOR shows promise in ACL assessment and remote rehabilitation. Full article

Background: Over the past decade, few echocardiographic investigations have assessed myocardial strain parameters in women with a history of hypertensive disorders of pregnancy (HDP), and their findings have been inconsistent. Moreover, no study has comprehensively evaluated deformation indices of all biventricular and biatrial chambers in women post-HDP. This study aimed to examine the structural and functional myocardial properties of all cardiac chambers in a cohort of women with prior HDP at six years after delivery. Methods: We analyzed a consecutive cohort of women with previous HDP and compared them with a control group of normotensive healthy women matched for age and body mass index (BMI). Both groups underwent standard transthoracic echocardiography (TTE) supplemented by a detailed speckle tracking echocardiography (STE) evaluation of biventricular and biatrial myocardial deformation, along with carotid ultrasound, at six years postpartum. The primary endpoint was subclinical myocardial dysfunction, defined by impaired left ventricular global longitudinal strain (LV-GLS < 20%), while the secondary endpoint was early carotid atherosclerosis, defined by common carotid artery intima-media thickness (CCA-IMT) ≥ 0.7 mm. Results: The study included 31 women with previous HDP (mean age 42.3 ± 5.9 years) and 30 matched controls without HDP history (mean age 40.8 ± 5.0 years). The average follow-up duration was 6.1 ± 1.3 years postpartum. Despite preserved and comparable systolic function on conventional TTE, most myocardial strain and strain rate measures in both ventricles and atria were significantly reduced in the HDP group compared to controls. Subclinical myocardial dysfunction was detected in 58.1% of women with prior HDP, and 67.7% exhibited increased CCA-IMT (≥0.7 mm). A history of pre-eclampsia (PE) was independently associated with subclinical myocardial dysfunction (HR 4.01, 95% CI 1.05–15.3, p = 0.03). Both third-trimester BMI (HR 1.21, 95% CI 1.07–1.38, p = 0.003) and PE (HR 6.38, 95% CI 1.50–27.2, p = 0.01) independently predicted early carotid atherosclerosis. Notably, a third-trimester BMI above 27 kg/m² showed optimal sensitivity and specificity for identifying the secondary outcome. Conclusions: A history of PE is independently associated with a higher risk of subclinical myocardial dysfunction and early carotid atherosclerosis at six years postpartum. Full article

Railway infrastructures necessitate the inspection of various elements to ensure operational safety. This study concentrates on five key components: rail, sleepers and ballast, track geometry, and catenary. The operational principles of the primary defect measurement sensors are elaborated, emphasizing the use of ultrasound, eddy currents, active and passive optical elements, accelerometers, and ground penetrating radar. Each sensor type is evaluated in terms of its advantages and limitations. Examples of mobile inspection platforms are provided, ranging from laboratory trains to draisines and track trolleys. The authors foresee future trends in railway inspection, including the implementation of IoT sensors, autonomous robots, and geospatial intelligence technologies. It is anticipated that the integration of sensors within both infrastructure and rolling stock will enhance maintenance and safety, with an increased utilization of autonomous robotic systems for hazardous and hard-to-reach areas. Full article

Background: Vascular imaging is essential for clinical practice, research, and the diagnosis and management of vascular diseases. Super-resolution ultrasound (SRUS) imaging is an emerging high-resolution imaging technique with broad applications in soft tissue vascular imaging. However, the impact of biological and clinical variables on its imaging accuracy is currently unknown. This study investigates these factors in an animal model and compares SRUS with contrast-enhanced µCT. Methods: Kidney scans from 29 Zucker rats (Zucker Diabetic Fatty and Zucker Lean) were retrospectively analysed. The left kidney was imaged in vivo using SRUS during microbubble infusion, then filled with Microfil and excised for ex vivo µCT. SRUS parameters and clinical variables were analysed, and SRUS scans were co-registered with µCT to compare vascular density measurements. Results: Mean arterial blood pressure and anaesthesia time showed significant linear relationships with SRUS microbubble detection and vascular track reconstruction. The anaesthesia time was also strongly correlated with vascular density measurement. Visualisation and velocity estimations of renal arteries were limited with SRUS. Ultrasound signal attenuation had significant impacts, particularly in cortical far-field imaging. Despite differences between kidney regions, the vascular density distribution did not differ considerably between SRUS and µCT datasets for whole-kidney imaging. Conclusions: This study outlines key factors SRUS users must consider for optimal technique use. Careful region selection and control of clinical variables ensure more reliable and comparable images. Further research is necessary to translate these findings from a rat model into clinical application. Full article

Sodium–glucose cotransporter 2 inhibitors (iSGLT2) have become the fourth pillar of the medical treatment for heart failure with reduced ejection fraction (HFrEF). However, the mechanisms of action of iSGLT2 remain poorly understood. The effectiveness of combined ARNI and iSGLT2 therapy in left ventricular (LV) remodeling is still under study. We aim to investigate the effects of ARNI + iSGLT2 combination therapy in patients affected by HFrEF in terms of ventricular remodeling using speckle tracking echocardiography (STE). In this observational study, 136 patients with HFrEF taking ARNI were enrolled. All patients were evaluated at baseline (before iSGLT2), at 3 months and at 12 months from the beginning of iSGLT2 therapy. Echocardiographic parameters, including STE analysis and volumetric and LV contractile function indices, were collected at the three timepoints. The objectives were (1) to evaluate the effects of ARNI + iSGLT2 combination therapy on ultrasound (US) measurements; (2) to evaluate the effects on the variation of laboratory data indicative of HF (NT-pro-BNP); and (3) to evaluate the medium-long term impact of the ARNI + iSGLT2 combination therapy in terms of major cardiovascular events (MACVE). After only three months of combined ARNI + iSGLT2 therapy, we reported a significant improvement in ventricular and atrial volumetric indices, systolic function indices and myocardial deformation parameters assessed by STE. We also reported a significant decrease in NTproBNP levels. This trend was confirmed at 12 months follow-up. Furthermore, narrowing down the analysis to patients who were already treated with ARNI when they started taking iSGLT2, we reported similar results in the improvement of US parameters and NTproBNP levels. Our study has shown that the ARNI + iSGLT2 combination therapy leads to a clinical improvement and positive ventricular remodeling. Even the single introduction of additional iSGLT-2 in HFrEF patients on an otherwise optimized therapy resulted in a significant improvement in US and laboratory variables. The results of our study suggest implementing iSGLT-2 therapy as soon as possible, as the structural and functional cardiac improvements achieved by these drugs are achieved in the short term and maintained in the long term. Full article

Transarterial chemoembolization (TACE) is a well-established treatment for intermediate-stage hepatocellular carcinoma (HCC), shown through randomized trials to improve survival compared to supportive care in patients with large, unresectable tumors who are not candidates for liver transplantation or local ablation. As the most commonly used transarterial intervention, TACE is also employed to downstage advanced HCC, allowing certain patients to become eligible for orthotopic liver transplantation under the Milan criteria. Despite its widespread use, variability in therapeutic outcomes highlights the need for improved procedural guidance. Recent advancements in intra-arterial contrast-enhanced ultrasound (IA CEUS) offer new opportunities to enhance TACE precision with real-time imaging that provides superior visualization of tumor vasculature and chemoembolic agent distribution. This review explores the role of IA CEUS in refining TACE for HCC, emphasizing its potential to increase intraprocedural accuracy and reduce the risk of incomplete tumor embolization. The enhanced spatial resolution of IA CEUS enables real-time tracking of embolic agent dispersion within tumor vessels, which could improve therapeutic efficacy by ensuring complete tumor targeting and minimizing non-target embolization. Additionally, IA CEUS may decrease procedural complications by allowing dynamic adjustment of embolic delivery based on real-time imaging feedback. By reviewing existing evidence on IA CEUS applications in TACE, this article highlights the modality’s potential to transform treatment protocols, improve outcomes, and expand the patient population eligible for TACE. Full article

This paper proposes a wavelet-based spatiotemporal feature extraction method for recognizing uncertain shapes and their deformations. Uncertain shapes, such as hand gestures and fetal movements, exhibit individual and trial-dependent variations, making their accurate recognition challenging. Our approach constructs shape feature vectors by integrating wavelet coefficients across multiple scales, ensuring robustness to rotation and translation. By analyzing the temporal evolution of these features, we can detect and quantify deformations effectively. Experimental evaluations demonstrate that the proposed method accurately identifies shape differences and tracks deformations, outperforming conventional approaches such as template matching and neural networks in adaptability and generalization. We further validate its applicability in tasks such as hand gesture recognition and fetal movement analysis from ultrasound videos. These results suggest that the proposed wavelet-based spatiotemporal feature extraction technique provides a reliable and computationally efficient solution for recognizing and tracking uncertain shapes in dynamic environments. Full article

Two-dimensional speckle-tracking echocardiography (2D-STE) is an advanced imaging technique that offers quantitative insights into myocardial function by analyzing the motion of speckles created during ultrasound–tissue interactions. This study aims to evaluate the reliability of 2D-STE by examining the impact of key technical parameters on global longitudinal strain (GLS) measurement accuracy and comparing two speckle-tracking analysis methods provided by GE Healthcare: quantitative analysis of the 2D strain (2D strain) and automated function imaging (AFI). The prospective study consisted of two cohorts. In the first cohort, including 16 healthy dogs, the influence of frame rate, heart rate variation, zoom, transducer frequency, and image foreshortening on speckle-tracking values was assessed. In the second cohort, which included 10 healthy dogs, 2D-STE parameters were obtained with the 2D strain and AFI to assess agreement between the methods and observer variability. Our findings indicate that foreshortening (p < 0.01, Cohen’s d: 0.52, CI: −17.81 to −24.83) and heart rate variability (p = 0.02, Cohen’s d: 0.72, CI: −18.07 to −26.23) significantly affect speckle-tracking measurements. While zoom, frame rate, and frequency did not show a significant impact. Additionally, while the 2D strain and AFI exhibited a strong correlation, a significant systematic bias was identified, with AFI underestimating strain values compared to the 2D strain. Intra- and inter-observer coefficients of variation (CV) were below 9% for both methods, supporting their reliability. These findings emphasize the need to optimize image acquisition and selection criteria, which enhances the accuracy and reliability of the speckle-tracking analysis. Full article

Ultrasonic signal processing methodologies use many signal parameters to be investigated, one of which is time-of-flight (ToF). There are many and various methods used to determine ToF, such as threshold detection, peak-based methods, cross-correlation, zero-crossing tracking algorithms, etc. The application of most of these methods becomes problematic when the background noise becomes high and the signal amplitude, frequency, or propagation velocity changes. In order to partially solve these problems, this paper proposes a new and simple method to determine the time-of-flight and center frequency of signals based on the use of zero-crossing times of filtered signals to calculate these parameters. Taking advantage of the idea that these zero-crossing times are concentrated around the maximum of the signal envelope, they were used as the time-of-flight of the signal. Together with the ToF, the center frequency of the signal was also determined. The proposed method was adapted to the processing of experimental signals obtained during various ultrasound investigations. By processing S₀ mode signals propagating in the sheet molding compound plate, the propagation velocity of this mode was calculated. Its value was compared with the value obtained by the 2D FFT method. The obtained results differed by 0.9%. Using simulated signals propagating in 1 mm-thick aluminum, the phase and group velocity segments of the A₀ mode were calculated. Their values differed by 0.7% from the theoretically calculated values of the dispersion curves by the SAFE method. Full article

Background/Objectives: Accurate assessment of tumor response to neoadjuvant chemotherapy (NAC) in breast cancer is critical for optimizing treatment strategies. While magnetic resonance imaging (MRI) and mammography are commonly used for response evaluation, they have inherent limitations. Ultrasound (US) has emerged as a promising, cost-effective, and real-time alternative. This study aimed to evaluate the effectiveness of US in tracking tumor regression during NAC and its correlation with pathologic tumor regression grade (TRG). Methods: This study included 282 breast cancer patients undergoing NAC. Tumor size was measured using ultrasound at three key time points: pre-chemotherapy, after four cycles, and post-chemotherapy. Spearman’s correlation was used to assess the relationship between US-measured tumor changes and TRG. Multinomial logistic regression and receiver operating characteristic (ROC) curve analyses were performed to determine the predictive accuracy of the measurements from our US in identifying pathologic complete response (pCR). Conclusions: Ultrasound is a reliable, real-time imaging tool for monitoring NAC response in breast cancer patients. Its ability to predict pCR and track tumor shrinkage highlights its potential for treatment adaptation. Standardization of US protocols and integration with AI-based analysis may further improve its clinical utility, making it a valuable adjunct in breast cancer treatment monitoring. Full article

Background/Objectives: The relationship between ultrasound parameters and fetal health in the context of intrauterine growth restriction (IUGR) pregnancies constitutes a significant focus of scholarly research. A comprehensive range of Doppler and echocardiographic evaluations, encompassing the umbilical artery, middle cerebral artery, ductus venosus, uterine arteries, cardiac contractility, ventricular filling, and the thickness of the interventricular septum, has been proposed in pathological pregnancies. Methods: The aim of this paper is to present an examination of these metrics and their implications for fetal health within the framework of IUGR pregnancies and to report a case series in which we analyzed the correlation of these factors. The assessment of these ultrasound indicators can help in better management of the cases in order to obtain better fetal outcomes. Results: Our case study presented dynamics corelated to the after-birth evaluation of the neonate, reflecting the importance of complete ultrasound assessment in high-risk cases. Conclusions: Speckle tracking echocardiography has significantly advanced our understanding of cardiac function in IUGR fetuses. As shown in our cases, it can be used to detect early signs of cardiac dysfunction, differentiating between FGR and SGA. Full article

Image-guided drug delivery is a method for tracking drug carriers for activation in specific lesions in the body. Image guidance uses the labelling of the drug or carrier and a clinically approved imaging modality. MRI (magnetic resonance image)-guided drug delivery has been considered for focused ultrasound tumour-targeted drug release. Liposomes are labelled for MRI tracking and the confirmation of drug delivery. In this study, we prepared two lipids conjugated to Gd-DOTA that confer MR imaging properties. Two lipid conjugates to DOTA, a C₁₈ (LCA-1) and a C₁₆ (LCA-2), were synthesised. The lipids were combined at different ratios within the lipid mix, and we investigated their effects on the liposome’s T_m using DSC (differential scanning calorimetry) and on relaxivity using NMR. The results show that when different combinations of LCA-1 and LCA-2 were introduced into the liposomes, their ratio affected both thermal drug release and relaxivity. As these lipids are part of the liposomal membrane, they confer tracking ability, and their effect on relaxivity due to thermal release could enable the confirmation of liposomal drug release using MRI at clinically relevant magnetic field strengths. Full article

Reliable acoustic coupling in a non-handheld mode and reducing the form factor of electronics are specific challenges in making ultrasound wearable. Applications relying on a large field of view (such as tracking of large muscles) induce a need for a large element count to achieve high image quality. In our work, we developed a 256-element linear array for imaging of abdominal muscles with four integrated custom-developed 8:32 multiplexer Integrated Circuits (ICs), allowing the array to be driven by our compact 32 ch electronics. The system is optimized for flexible use in R&D applications and allows adjustable transmit voltages (up to +/−100 V), arbitrary delay patterns, and 12-bit analog-to-digital conversion (ADC) with up to 50 MSPS and wireless (21.6 MBit/s) or USB link. Image metrics (SLL, FWHM) were very similar to a fully populated array driven with a 256 ch system. The contrast allowed imaging of lesions down to 7 cm in the phantom. In a first in-vivo study, we demonstrated reliable acoustic contact even during exercise and were able to visualize deep abdominal muscles such as the TrA. In combination with a muscle tracking algorithm, the change of thickness of the TrA during SSE could be monitored, demonstrating the potential of the approach as biofeedback for physiotherapy training. Full article

Background: Ultrasonography is commonly employed during thoracic regional anesthesia; however, its accuracy can be affected by factors such as obesity and poor penetration through the rib window. Needle-sized ultrasound transducers, known as intra-needle ultrasound (INUS) transducers, have been developed to detect the pleura and fascia using a one-dimensional radio frequency mode ultrasound signal. In this study, we aimed to use time-frequency analysis to characterize the pleural signal and develop an automated tool to identify the pleura during medical procedures. Methods: We developed an INUS system and investigated the pleural signal it measured by establishing a phantom study, and an in vivo animal study. Signals from the pleura, endothoracic fascia, and intercostal muscles were analyzed. Additionally, we conducted time- and frequency-domain analyses of the pleural and alveolar signals. Results: We identified the unique characteristics of the pleura, including a flickering phenomenon, speckle-like patterns, and highly variable multi-band spectra in the ultrasound signal during the breathing cycle. These characteristics are likely due to the multiple reflections from the sliding visceral pleura and alveoli. This automated identification of the pleura can enhance the safety for thoracic regional anesthesia, particularly in difficult cases. Conclusions: The unique flickering pleural signal based on INUS can be processed by time-frequency domain analysis and further tracked by an auto-identification algorithm. This technique has potential applications in thoracic regional anesthesia and other interventions. However, further studies are required to validate this hypothesis. Key Points Summary: Question: How can the ultrasound pleural signal be distinguished from other tissues during breathing? Findings: The frequency domain analysis of the pleural ultrasound signal showed fast variant and multi-band characteristics. We suggest this is due to ultrasound distortion caused by the interface of multiple moving alveoli. The multiple ultrasonic reflections from the sliding pleura and alveoli returned in variable and multi-banded frequency. Meaning: The distinguished pleural signal can be used for the auto-identification of the pleura for further clinical respiration monitoring and safety during regional anesthesia. Glossary of Terms: intra-needle ultrasound (INUS); radio frequency (RF); short-time Fourier transform (STFT); intercostal nerve block (ICNB); paravertebral block (PVB); pulse repetition frequency (PRF). Full article

Non-expandable lung (NEL) occurs when the lung fails to fully re-expand after pleural fluid drainage, complicating management and limiting therapeutic options. Diagnosis, based on clinical symptoms, pleural manometry, and traditional imaging, is often delayed to the peri- or post-procedural stages, leading to improper management, complications, and higher healthcare costs. Therefore, early, pre-procedural diagnostic methods are needed. Thoracic ultrasound (TUS) has emerged as a non-invasive tool with the potential to enhance diagnostic accuracy and guide clinical decisions, yet, it remains inadequately studied within the context of NEL. We conducted a non-systematic narrative review using a structured methodology, including a comprehensive database search, predefined inclusion criteria, and QUADAS-2 quality assessment. This approach ensured a rigorous synthesis of evidence on TUS in NEL, with the aim of identifying knowledge gaps and guiding future studies. Non-invasive, real-time, bedside M-mode TUS has demonstrated efficacy in predicting NEL prior to thoracentesis by detecting an absent sinusoidal sign and reduced atelectatic lung movement. Emerging experimental techniques, including 2D shear wave elastography (SWE), speckle tracking imaging (STI) strain analysis, the lung/liver echogenicity (LLE) ratio, TUS assessment of dynamic air bronchograms, and pleural thickening evaluation, show additional potential to enhance pre-procedural NEL detection. However, all these methods have significant limitations that require further comprehensive investigation. Despite their significant promise, TUS modalities for early NEL detection still require rigorous validation and standardization before broad clinical use. A multimodal diagnostic approach, combining clinical manifestations, pleural manometry, radiologic and ultrasonographic findings, along with emerging techniques (once fully validated), may provide the most extensive framework for NEL. Regardless of advancements, patient-centered care and shared decision-making remain essential. Further research is needed to improve outcomes, reduce healthcare costs, and enhance long-term treatment strategies. Full article