Ultrasound Tissue Research Articles

Evaluating Skin Involvement in Systemic Sclerosis Using High-Frequency Ultrasound and Virtual Touch Tissue Imaging

ObjectiveThis study aimed to explore the diagnostic significance of high-frequency ultrasound combined with visual touch tissue imaging quantification (VTIQ) in the diagnosis and management of systemic sclerosis (SSc). MethodsPatients diagnosed with SSc and normal volunteers were recruited and divided into an experimental group and a control group, with 30 cases in each group, respectively. The skin thickness at six sites was assessed using high-frequency ultrasound, and the shear wave velocity (SWV) was determined using the VTIQ method. The differences in skin thickness and SWV between the experimental group and the control group were compared and a receiver operating characteristic (ROC) curve was plotted. The value of high-frequency ultrasound, VTIQ, and high-frequency ultrasound combined with VTIQ for evaluating skin involvement in SSc was determined. ResultsThe difference in SWV sum at six sites and the thickness sum was statistically significant (all p = 0.000 < 0.05) from that of the control group, and there was a strong association between the SWV sum, thickness sum, and Rodnan skin score at the six sites in the experimental group (p = 0.000, r = 0.726; p = 0.000, r = 0.679). Based on the ROC curve, the area under the curve (AUC) for high-frequency ultrasound examination was 0.789. The AUC for VTIQ examination was 0.893, while the AUC for high-frequency ultrasound combined with VTIQ examination was 0.923. The combined examination method showed the highest AUC, indicating the best diagnostic performance. ConclusionThe integration of high-frequency ultrasound and VTIQ provides a quantitative approach for assessing the extent of skin involvement in SSc patients, offering valuable insights for clinical diagnosis and treatment purposes.

Assessing Tissue Damage Around a Tape Spring Steerable Needle With Sharp Turn Radii.

Steerable needles are a novel technology that offers a wide range of uses in medical diagnostics and therapeutics. Currently, there exist several steerable needle designs in the literature, however, they are limited in their use by the number of possible turns, turn radius, and tissue damage. We introduce a novel design of a tape spring steerable needle, capable of multiple turns, that minimizes tissue damage. In this study, we measure the turning radius of our steerable needle in porcine liver tissue in vitro with ultrasound and estimate tissue damage in gel blocks using image analysis and 3D plaster casting. We were able to demonstrate our steerable needle's ability to steer through biological tissue, as well as introduce a novel method for estimating tissue damage. Our findings show that our needle design showed lower damage compared to similar designs in literature, as well as tissue stiffness being a protective factor against tissue damage.

Measuring Ultrasonographic Thickness of the Achilles Tendon Insertion Is Less Reliable Than the Midportion in Healthy Tendons and Patients With Tendinopathy.

Ultrasound is the preferred imaging method in the diagnostic process of Achilles tendinopathy (AT). Ultrasound tissue characterization (UTC) is a frequently used, standardized and valid method to assess tendon geometry in AT patients. It is unknown whether UTC is reliable for measuring Achilles tendon thickness. The aim of the study was to assess intra- and inter-rater reliability of Achilles tendon thickness measurements using UTC in both asymptomatic individuals and patients with AT, and to evaluate if the reliability of thickness measurements differs between the midportion and insertional area. Exactly 50 patients with AT and 50 asymptomatic individuals were included. Using the conventional US and standardized UTC procedure maximum thickness was measured in the midportion and insertion region. To determine inter- and intra-rater reliabilities, the intraclass correlation coefficient (ICC) was used. The ICC values for inter- and intra-rater reliability were classified as "excellent," for the AT group (0.93 [95% CI: 0.88-0.96] and 0.95 [0.92-0.97]) and asymptomatic participants (0.91 [0.87-0.94] and 0.94 [0.92-0.96]). The reliability of measuring tendon thickness in the midportion region was "excellent," with both inter-rater (0.97 [0.95-0.98]) and intra-rater (0.98 [0.96-0.99]) ICC values indicating high levels of agreement. In the insertional region, ICC values for inter-rater (0.79 [0.69-0.87]) and intra-rater (0.89 [0.84-0.93]) reliability were "moderate to good." We showed excellent reliability for measuring the US thickness of the midportion and good reliability of measuring the insertional region in patients with AT. Significantly lower ICCs were observed for the reliability of thickness measurements in the insertional region when compared with the midportion.

Where is Your Pain? Achilles Tendinopathy Pain Location on Loading Is Different to Palpation, Imaging and Recall Location.

OBJECTIVE: To describe and compare pain maps reported during Achilles tendon loading exercises with recall pain location, in people with pain on palpation in their Achilles tendon and tendon pathology on imaging. DESIGN: Cross-sectional analysis of baseline RCT. METHOD: Participants were recruited from a larger Achilles tendinopathy clinical trial. Inclusion criteria were at least 2-month self-reported history of Achilles tendinopathy, midtendon palpation pain, and pathology on ultrasound tissue characterization. Participants were asked to identify their Achilles tendon pain location on a pain map with 8 prespecified locations while at rest prior to loading (recall pain), and subsequently during tendon loading exercises (loading pain). Participants could select multiple locations or select "other" if the locations did not represent their pain. RESULTS: Ninety-three participants were included (93% of participants from a clinical trial). The locations of pain on loading were diverse; all 8 pain locations (and an "other" option) were represented within this sample. Twenty-five percent of participants did not report pain with loading (n = 23 of 93). Of the 70 participants with loading pain, recall pain location differed to loading pain location in 40% (n = 28 of 70) of the participants. CONCLUSION: Palpation pain location, recall pain location, or location of pathology on imaging were not valid proxies for load-related pain in the Achilles tendon. How different pain locations respond to treatment is unknown. Some pathologies (eg, plantaris) have clear pain locations (eg, medial tendon), and assessing pain location may assist differential diagnosis. J Orthop Sports Phys Ther 2024;54(1):1-9. Epub 7 December 2023. doi:10.2519/jospt.2023.12131.

Ultrasound tissue scatterer distribution imaging: An adjunctive diagnostic tool for shear wave elastography in characterizing focal liver lesions

ObjectivesFocal liver lesion (FLL) is a prevalent finding in cross-sectional imaging, and distinguishing between benign and malignant FLLs is crucial for liver health management. While shear wave elastography (SWE) serves as a conventional quantitative ultrasound tool for evaluating FLLs, ultrasound tissue scatterer distribution imaging (TSI) emerges as a novel technique, employing the Nakagami statistical distribution parameter to estimate backscattered statistics for tissue characterization. In this prospective study, we explored the potential of TSI in characterizing FLLs and evaluated its diagnostic efficacy with that of SWE. MethodsA total of 235 participants (265 FLLs; the study group) were enrolled to undergo abdominal examinations, which included data acquisition from B-mode, SWE, and raw radiofrequency data for TSI construction. The area under the receiver operating characteristic curve (AUROC) was used to evaluate performance. A dataset of 20 patients (20 FLLs; the validation group) was additionally acquired to further evaluate the efficacy of the TSI cutoff value in FLL characterization. ResultsIn the study group, our findings revealed that while SWE achieved a success rate of 49.43 % in FLL measurements, TSI boasted a success rate of 100 %. In cases where SWE was effectively implemented, the AUROCs for characterizing FLLs using SWE and TSI stood at 0.84 and 0.83, respectively. For instances where SWE imaging failed, TSI achieved an AUROC of 0.78. Considering all cases, TSI presented an overall AUROC of 0.81. There was no statistically significant difference in AUROC values between TSI and SWE (p > 0.05). In the validation group, using a TSI cutoff value of 0.67, the AUROC for characterizing FLLs was 0.80. ConclusionsIn conclusion, ultrasound TSI holds promise as a supplementary diagnostic tool to SWE for characterizing FLLs.

Comparative Study of Ultrasound Tissue Motion Tracking Techniques for Effective Breast Ultrasound Elastography

Breast cancer is the most common and deadly cancer in women, where early detection is of the utmost importance as survival rates decrease with the advancement of the disease. Most available methods of breast cancer screening and evaluation lack the ability to effectively differentiate between benign and malignant lesions without a biopsy. Ultrasound elastography (USE) is a cost-effective method that can potentially provide an initial malignancy assessment at the bedside. One of the challenges, however, is the uncertainty of tissue displacement data when performing USE due to out-of-plane movement of the tissue during mechanical stimulation, in addition to the computational efficiency necessary for real-time image reconstruction. This work presents a comparison of four different theoretically sound displacement estimators for their ability in tissue Young’s modulus reconstruction level with an emphasis on quality-to-runtime ratio to determine which estimators are most suitable for real-time USE systems. The methods are known in literature as AM2D, GLUE, OVERWIND, and SOUL methods. The effectiveness of each method was assessed as a stand-alone method or in combination with a strain field enhancement technique known as STREAL, which was recently developed using tissue mechanics-based regularization. The study was performed using radiofrequency US data pertaining to in silico and tissue mimicking phantoms in addition to clinical data. This data was used to generate tissue displacement fields employed to generate axial and lateral strain images before Young’s modulus images were reconstructed. The study indicates that the AM2D displacement estimator, which is an older and computationally less involved method, along with a tissue-mechanics-based image processing algorithm, performs very well, with high CNR, SNR, and preservation of tumor heterogeneity obtained at both strain and stiffness image levels, while its computation run-time is much lower compared to other estimation methods. As such, it can be recommended for incorporation in real-time USE systems.

Application of ultrasonic cavitation combined with rapid pathological tissue processing method of novel environmental protection reagents in pathological diagnosis.

To investigate the effect of pretreatment of tumor biopsy specimens using fixed, dehydrated and transparent three-in-one composite environmental protection reagent ultrasound tissue rapid processing technique on subsequent detection. From April 2020 to October 2020, a total of 100 cases including breast, stomach and lung tissues were submitted to our diagnosis, and 3 specimens were collected from each specimen and divided into the control group (traditional biopsy tissue processing method), experimental group 1 (3.7% neutral buffered formaldehyde fixation, compound environmental protection reagent rapid ultrasound tissue processing technique, processing temperature 48 °C, time 20 minutes/time, twice, wax immersion temperature 62 °C, time 25 minutes) and experimental group 2 (3.7% neutral buffered formaldehyde fixation, compound environmental protection reagent rapid ultrasound tissue processing technique, processing temperature 50 °C, time 15 min/time, twice, Wax dipping temperature 64 °C, time 20 minutes). The effects of different treatments on hematoxylin eosin section, immunohistochemistry (IHC) and molecular pathological examination were analyzed. The detection results of hematoxylin eosin, fluorescence in situ hybridization and IHC against human epidermal growth factor receptor 2 and epidermal growth factor receptor gene mutation in the experimental group were completely consistent with those in the control group. There was no significant difference in the results between experiment 1 and experiment 2 groups. The rapid processing technique of ultrasound tissue with compound environmental protection reagent can be applied to the rapid detection of tumor biopsy specimens, and different processing temperatures and durations have no significant effect on the accuracy of HE staining, IHC, fluorescence in situ hybridization and gene mutation detection.

Quadriceps strength, patellar tendon quality, relative load exposure, and knee symptoms in male athletes before the anterior cruciate ligament reconstruction.

Anterior cruciate ligament (ACL) injuries cause knee instability, knee pain, weight-bearing adjustments, and functional deficits but their association to patellar tendon quality is unknown. Our purpose was to investigate quadriceps strength, patellar tendon quality, relative load exposure, perceived knee stability, knee pain, extension angle, and time from ACL injury; in addition to examining their relative associations. Injured and uninjured legs of 81 male athletes of different sports with a unilateral ACL injury (18-45 years) were examined. Participants reported location and intensity of knee pain and their perceived stability using a numerical rating scale (NRS 0-10). Strength was tested with an isokinetic device. Tendon quality was measured using ultrasound tissue characterization. Means ± standard deviation (SD) of perceived knee stability, knee extension angle, knee pain, isokinetic quadriceps strength in relation to body mass, proportion of echo-types (I-IV), tendon volume, and number of days from ACL injury to assessment are reported. Values of effect sizes (ES) and correlations (rs) were calculated. ACL injured leg demonstrated reduced reported knee stability (6.3 ± 2.5), decreased knee extension angle (-0.7 ± 3.1° vs. -2.7 ± 2.2°; ES = 0.7; P < 0.001), greater knee pain (NRS 3.1 ± 2.2 vs. 0.0 ± 0.1; ES = 2.0; P < 0.001), and 22% lower quadriceps strength (228.0 ± 65.0 vs. 291.2 ± 52.9 Nm/kg: ES = 1.2; P < 0.001) as compared to the uninjured leg. However, patellar tendons in both legs displayed similar quality. Quadriceps strength was associated with stability (rs = -0.54; P < 0.001), pain (rs = -0.47; P < 0.001), extension angle (rs = -0.39; P < 0.001), and relative load exposure (rs = -0.34; P < 0.004). Echo-types distribution was beneficially associated with time from ACL injury (rs range: -0.20/ -0.32; P < 0.05). ACL injured athletes displayed knee pain, extension deficit, and weaker quadriceps in the injured leg. While there were no differences in patellar tendon quality between legs, longer time from ACL injury showed better tendon quality.

An efficient adaptive method based on empirical wavelet transform for ultrasound tissue harmonic imaging

In this study, an efficient adaptive method based on the empirical wavelet transform (EA_EWT) was developed to separate harmonics from ultrasonic radio frequency (RF) echo signals for B-mode imaging. The spectrum for each RF scan line was calculated, and a meaningful partition based on the scale-space representation was performed on the preprocessed spectrum, from which the harmonic boundaries were automatically determined. Thereafter, the harmonic components were obtained using the empirical scaling function and empirical wavelets. Finally, harmonic signals were obtained after separating all RF scan lines in a frame for imaging. In the experiments, the EA_EWT method was used to separate the ultrasonic RF signals simulated by CREANUIS and obtained from the human carotid artery. The results were compared with separation based on bandpass filtering (BPF), pulse inversion (PI), and complete ensemble empirical mode decomposition with adaptive noise (S_CEEMDAN) methods. The EA_EWT-based simulation results were superior to the PI-based simulation results with shifted scatterer models and comparable to the BPF- and S_CEEMDAN-based results. In the in vivo measurements, the EA_EWT-based harmonic images exhibited a mean contrast, contrast-to-noise ratio, and tissue-to-clutter ratio of 0.896, 3.973, and 8.306, respectively. The processing times of the BPF, PI, and EA_EWT methods were 0.06 s, 0.01 s, and 0.214 s, respectively, which were significantly shorter than that of the S_CEEMDAN method (113.26 s). The EA_EWT approach may be used in practice to generate more precise diagnostic data since it effectively executes a better separation of harmonic components for B-mode imaging.

The mouthpiece chamber vacuum pattern indicates the cessation of milk flow and suits as an indicator to reduce teat end vacuum at a quarter level

We investigated the suitability of the quarter mouthpiece chamber vacuum (MPCV) as an indicator for cessation of quarter milk flow to potentially adjust the teat end vacuum at a quarter level. We tested the hypothesis that a MPCV increase is a clear indicator of quarter milk flow cessation. In addition, we tested if a quarter-individual vacuum reduction at MPCV increase reduces the mechanical effect on the teat. Ten dairy cows were milked twice daily with a quarter-specific vacuum supply with continuously high (51 kPa; TRT51) or low vacuum setting (41 kPa; TRT41), or high vacuum setting combined with a quarter-specific vacuum reduction by 10 kPa immediately after the quarter-specific MPCV increase (TRT51/41). Whole udder milk flow was continuously recorded. Each treatment was repeated at 4 subsequent milkings. The high vacuum settings (TRT51; TRT51/41) reached higher values in peak flow rate and average milk flow and consequently shorter machine-on time. The time from start of milking until the steep increase of the MPCV was shorter in front than rear quarters, and hence the time from start of MPCV increase until end of milking was longer in front than rear teats. Teat condition of the right front teats was measured for teat wall diameter by ultrasound and teat tissue thickness by cutimeter at 5 and 20 min after each experimental milking. The teat measurements were taken at the teat tip (distal barrel) and 2 cm above the teat tip (proximal barrel). The proximal teat wall diameter tended to be higher in TRT51 than in TRT41, both 5 and 20 min after milking. The distal teat wall diameter at 5 min was greater in TRT51 than in TRT41. In TRT51/41 the teat wall diameter at both locations was intermediate, not significantly different from either TRT51 or TRT41. The distal teat tissue thickness was greater in TRT51 than in TRT41, and tended to be greater in TRT51/41 than in TRT41 at 5 min. The proximal teat tissue thickness at 5 min was higher in TRT51 and TRT51/41 than in TRT41. The teat tissue thickness decreased from 5 to 20 min only in the proximal barrel. The quarter-individual MPCV increase appears to be a suitable indicator of the cessation of milk flow. The lack of a significant reduction of mechanical effect on the teat by a reduced vacuum of 41 kPa indicates that the vacuum level chosen may be still too high under conditions of a separate vacuum supply for each quarter, which prevents a vacuum drop caused by the whole udder milk flow.

Role of endoscopic ultrasound and endoscopic ultrasound-guided tissue acquisition in diagnosing hepatic focal lesions.

Endoscopic ultrasonography (EUS) has become an established method in diagnostic and therapeutic procedures in gastroenterology; however, it has recently gained a growing role in hepatology. To evaluate the role of EUS features, strain elastography (SE), and EUS-tissue acquisition in diagnosing hepatic focal lesions (HFLs) that could affect further management. This cross-sectional study included 215 patients with pancreatic, biliary, or gastrointestinal malignancies referred for EUS examination. HFLs were identified in 43 patients (20%), and EUS-guided tissue acquisition was performed from these lesions. EUS features were highly sensitive (100%) but much less specific (57%) in diagnosing HFLs; the overall accuracy was 94%. Real-time elastography was also very sensitive (97%) but less specific (67%) in diagnosing HFLs; however, the overall accuracy was 92%. EUS tissue acquisition was extremely sensitive (100%) and specific (100%), with a 100% overall diagnostic accuracy. The diagnostic utility of EUS-guided tissue acquisition was extremely accurate in diagnosing HFLs. EUS characteristics and real-time SE accurately predicted the histological diagnosis of both benign and malignant HFLs.

Prognostic value of ultrasound tissue characterisation for a recurrence of mid-portion Achilles tendinopathy in military service members: a prospective cohort study

IntroductionTendon structure in mid-portion Achilles tendinopathy (mid-AT) appears poorly associated with symptoms. Yet, degenerative tendon changes on imaging have been associated with an increased risk of mid-AT. We aimed to...

Changes in cerebral connectivity and brain tissue pulsations with the antidepressant response to an equimolar mixture of oxygen and nitrous oxide: an MRI and ultrasound study.

Nitrous oxide (N2O) has recently emerged as a potential fast-acting antidepressant but the cerebral mechanisms involved in this effect remain speculative. We hypothesized that the antidepressant response to an Equimolar Mixture of Oxygen and Nitrous Oxide (EMONO) would be associated with changes in cerebral connectivity and brain tissue pulsations (BTP). Thirty participants (20 with a major depressive episode resistant to at least one antidepressant and 10 healthy controls-HC, aged 25-50, only females) were exposed to a 1-h single session of EMONO and followed for 1 week. We defined response as a reduction of at least 50% in the MADRS score 1 week after exposure. Cerebral connectivity of the Anterior Cingulate Cortex (ACC), using ROI-based resting state fMRI, and BTP, using ultrasound Tissue Pulsatility Imaging, were compared before and rapidly after exposure (as well as during exposure for BTP) among HC, non-responders and responders. We conducted analyses to compare group × time, group, and time effects. Nine (45%) depressed participants were considered responders and eleven (55%) non-responders. In responders, we observed a significant reduction in the connectivity of the subgenual ACC with the precuneus. Connectivity of the supracallosal ACC with the mid-cingulate also significantly decreased after exposure in HC and in non-responders. BTP significantly increased in the three groups between baseline and gas exposure, but the increase in BTP within the first 10 min was only significant in responders. We found that a single session of EMONO can rapidly modify the functional connectivity in the subgenual ACC-precuneus, nodes within the default mode network, in depressed participants responders to EMONO. In addition, larger increases in BTP, associated with a significant rise in cerebral blood flow, appear to promote the antidepressant response, possibly by facilitating optimal drug delivery to the brain. Our study identified potential cerebral mechanisms related to the antidepressant response of N2O, as well as potential markers for treatment response with this fast-acting antidepressant.

Congenital heterotopic gastrointestinal duplication cyst of the face: a rare case report

Gastrointestinal duplication (GDC) cysts have various synonyms; choristoma, enterocystoma, and duplication cyst. They are infrequent congenital benign lesions diagnosed mainly in children in the first decade of life, comprising approximately less than 5% of the pediatric population with a predilection for the male sex. It is exceedingly rare in the oral cavity but it is possible, particularly on the tongue, floor of the mouth, and pharynx. From 1895 until 1994, 30 cases of this lesion in the oral cavity were reported. Nowadays, none of the authors reported a GDC in the facial region. We report an exceptional case of heterotopic gastrointestinal duplication cysts (HGDC) in the facial region of a 13 -years -old male teenager who was referred to our medical department for an evaluation of a painless progressive facial asymmetry. In the first instance, the ultrasound facial soft tissue was made with a 6.5 MHz convex transducer, reporting a big anechoic image with regular borders to a 60 x 26 x 56 mm diameter with a 46cc approximate volume. Following this, a non-contrast magnetic resonance image was executed with an open Philips PanoramaⓇ machine performed at 3T, reporting a hyperintense image in T2-weighted (repetition time msec/echo time msec: 5,500/112) sagittal sequence and FLAIR-weighted (5,714/80) axial sequence; and an isointense image in T1-weighted (24/80) coronal sequence to 54 x 30 x 51 mm diameter compatible with space occupant lesion with interior walls. A complete tumor resection was achieved under balanced general anesthesia, and the specimen was sent for histological examination. Microscopic examination showed a cystic cavity lined mostly by mucous secretory gastrointestinal epithelium and other areas by stratified squamous epithelium. The cystic wall was composed of fibrous connective tissue and contains abundant gastric cells. Its deepest portion exhibits a smooth muscle layer. In summary, HGDC is an unusual congenital head and neck lesion, but it should be considered in the differential diagnosis of neonates and children. The diagnosis of gastrointestinal tract duplications may be suggested by imaging studies; however, the correct diagnosis is defined by histopathologic analysis. Due to the risk of destruction potential and malignant transformation, HGDC should be treated surgically by complete excision.

Ультразвуковая эндоназальная дакриоцисториностомия в лечении рецидивирующего дакриоцистита новорожденного

Purpose. To evaluate early and long-term functional and anatomic results of surgical treatment of lacrimal pathways obstruction (LPO) in children with endonasal dacryocystorhinostomy (EDCR) method using ultrasound bone tissue dissector for the formation of nasolacrimal anastomosis. Material and methods. Surgical treatment of recurrent dacryocystitis of newborn (DN) after repeated unsuccessful «blind»lacrimal pathways probing in children with nasolacrimal duct obstruction, including cases of congenital nasolacrimal duct atresia. Bone «window» of the nasolacrimal anastomosis during endoscopic EDCR was formed using SONOCA 185 piezoelectric ultrasound dissector. In total, 14 children, 8 girls and 6 boys aged from 3 to 11 years (mean, 6 years) were operated with follow-up period of 6 months. Results. It was found that in all the children an adequate nasolacrimal anastomosis was formed without significant bleeding episodes both intraoperatively and in the early post-op period. No cases of destruction of the medial wall of the lacrimal sac were marked. Functional success was achieved in 92.8% (13 of14 cases). In 7.2% (1 of 14cases) there was a postoperative granuloma of the mucous in the rhinostoma region which was a partial obstacle for tear flow. Conclusions. Controlled low temperature process of nasal bones ultrasound dissection during EDCR in children allows formation of an adequate bone «window»and, therefore, a valuable nasolacrimal anastomosis in narrow nasal passages, makes the surgical procedure much easier and quicker, enables better healing of soft tissues in a shorter period. Key words: recurrent dacryocystitis of newborns, endonasal endoscopic dacryocystorhinostomy, ultrasound dissection of bone tissue

Calibrating Data Mismatches in Deep Learning-Based Quantitative Ultrasound Using Setting Transfer Functions.

Deep learning (DL) can fail when there are data mismatches between training and testing data distributions. Due to its operator-dependent nature, acquisition-related data mismatches, caused by different scanner settings, can occur in ultrasound imaging. As a result, it is crucial to mitigate the effects of these mismatches to enable wider clinical adoption of DL-powered ultrasound imaging and tissue characterization. To address this challenge, we propose an inexpensive and generalizable method that involves collecting a large training set at a single setting and a small calibration set at each scanner setting. Then, the calibration set will be used to calibrate data mismatches by using a signals and systems perspective. We tested the proposed solution to classify two phantoms using an L9-4 array connected to a SonixOne scanner. To investigate generalizability of the proposed solution, we calibrated three types of data mismatches: pulse frequency mismatch, focus mismatch, and output power mismatch. Two well-known convolutional neural networks (CNNs), i.e., ResNet-50 and DenseNet-201, were trained using the ultrasound radio frequency (RF) data. To calibrate the setting mismatches, we calculated the setting transfer functions. The CNNs trained without calibration resulted in mean classification accuracies of around 52%, 84%, and 85% for pulse frequency, focus, and output power mismatches, respectively. By using the setting transfer functions, which allowed a matching of the training and testing domains, we obtained the mean accuracies of 96%, 96%, and 98%, respectively. Therefore, the incorporation of the setting transfer functions between scanner settings can provide an economical means of generalizing a DL model for specific classification tasks where scanner settings are not fixed by the operator.

Investigation of tongue hardness using ultrasound elastography in children during growth period

ABSTRACT Purpose Previous studies, the changes in tongue hardness with growth were scarcely ever described, but tongue pressure and morphology were the focus of them. Given that, we decided to use ultrasound to examine the changes in tongue hardness during growth. Materials and methods 60 paediatric patients (30 boys and 30 girls) aged 6 to 11 years (mean age, 8.5 ± 1.7 years) who visited the Department of Orthodontics, Showa University Dental Hospital were selected for the study. Tongue hardness was measured using real-time ultrasound tissue elastography. The measured values of tongue elasticity were subjected to the Shapiro – Wilk test, and QQ plot for checking the normality. Pearson’s correlation coefficient was used to confirm the significance of the relationship among the three measurements of tongue elasticity, age, sex, height, weight, BMI, body fat, tongue pressure, and hand strength. Results We confirmed that the use of ultrasound SWE and SE are valuable for the measurement of tongue elasticity. A negative correlation between age and tongue elasticity SE (extraoral) (r = −0.26, P < 0.05), body weight and tongue elasticity SE (extraoral) (r = −0.30, P =＜0.05). Conclusion It was suggested that tongue hardness changes with changes with age. The balance between the tongue and perioral muscles is affected with the position of the teeth. Perioral muscle function is closely associated with malocclusion onset, particularly during childhood when maxillofacial growth and development are rapid. Therefore, the use of ultrasonography device can aid in the evaluation of treatments to improve perioral muscle function.

A Study on a Parameter Estimator for the Homodyned K Distribution Based on Table Search for Ultrasound Tissue Characterization.

The homodyned K (HK) distribution is considered to be the most suitable distribution in the context of tissue characterization; therefore, the search for a rapid and reliable parameter estimator for HK distribution is important. We propose a novel parameter estimator based on a table search (TS) for HK parameter estimates. The TS estimator can inherit the strength of conventional estimators by integrating various features and taking advantage of the TS method in a rapid and easy operation. Performance of the proposed TS estimator was evaluated and compared with that of XU (the estimation method based on X and U statistics) and artificial neural network (ANN) estimators. The simulation results revealed that the TS estimator is superior to the XU and ANN estimators in terms of normalized standard deviations and relative root mean squared errors of parameter estimation, and is faster. Clinical experiments found that the area under the receiver operating curve for breast lesion classification using the parameters estimated by the TS estimator could reach 0.871. The proposed TS estimator is more accurate, reliable and faster than the state-of-the-art XU and ANN estimators and has great potential for ultrasound tissue characterization based on the HK distribution.

Parallelized ultrasound homodyned-K imaging based on a generalized artificial neural network estimator

The homodyned-K (HK) distribution model is a generalized backscatter envelope statistical model for ultrasound tissue characterization, whose parameters are of physical meaning. To estimate the HK parameters is an inverse problem, and is quite complicated. Previously, we proposed an artificial neural network (ANN) estimator and an improved ANN (iANN) estimator for estimating the HK parameters, which are fast and flexible. However, a drawback of the conventional ANN and iANN estimators consists in that they use Monte Carlo simulations under known values of HK parameters to generate training samples, and thus the ANN and iANN models have to be re-trained when the size of the test sets (or of the envelope samples to be estimated) varies. In addition, conventional ultrasound HK imaging uses a sliding window technique, which is non-vectorized and does not support parallel computation, so HK image resolution is usually sacrificed to ensure a reasonable computation cost. To this end, we proposed a generalized ANN (gANN) estimator in this paper, which took the theoretical derivations of feature vectors for network training, and thus it is independent from the size of the test sets. Further, we proposed a parallelized HK imaging method that is based on the gANN estimator, which used a block-based parallel computation method, rather than the conventional sliding window technique. The gANN-based parallelized HK imaging method allowed a higher image resolution and a faster computation at the same time. Computer simulation experiments showed that the gANN estimator was generally comparable to the conventional ANN estimator in terms of HK parameter estimation performance. Clinical experiments of hepatic steatosis showed that the gANN-based parallelized HK imaging could be used to visually and quantitatively characterize hepatic steatosis, with similar performance to the conventional ANN-based HK imaging that used the sliding window technique, but the gANN-based parallelized HK imaging was over 3 times faster than the conventional ANN-based HK imaging. The parallelized computation method presented in this work can be easily extended to other quantitative ultrasound imaging applications.

Comparative Study of Muscle Hardness during Water-Walking and Land-Walking Using Ultrasound Real-Time Tissue Elastography in Healthy Young People

Compared with land-walking, water-walking is considered to be beneficial as a whole-body exercise because of the characteristics of water (buoyancy, viscosity, hydrostatic pressure, and water temperature). However, there are few reports on the effects of exercise in water on muscles, and there is no standard qualitative assessment method for muscle flexibility. Therefore, we used ultrasound real-time tissue elastography (RTE) to compare muscle hardness after water-walking and land-walking. Participants were 15 healthy young adult males (24.8 ± 2.3 years). The method consisted of land-walking and water-walking for 20 min on separate days. The strain ratio of the rectus femoris (RF) and medial head of gastrocnemius (MHGM) muscles were measured before and immediately after walking using RTE to evaluate muscle hardness. In water-walking, the strain ratio significantly decreased immediately after water-walking, with p < 0.01 for RF and p < 0.05 for MHGM, indicating a significant decrease in muscle hardness after water-walking. On the other hand, land-walking did not produce significant differences in RF and MHGM. Muscle hardness after aerobic exercise, as assessed by RTE, was not changed by land walking but was significantly decreased by water walking. The decrease in muscle hardness induced by water-walking was thought to be caused by the edema reduction effect produced by buoyancy and hydrostatic pressure.