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The aim of this study was to study the effects of tepy2 diabetes (T2DM) and treatment cortisone on the foot bones. A total of 123 Iraqi men and women participated in the study (18 males and 105 females), with type 2 diabetes receiving cortisone therapy. Quantitative Ultrasound (QUS) was used to evaluate osteoporosis, speed of sound (SOS), broadband ultrasound attenuation (BUA), and calcaneus bone quality index (BQI). A dual x-ray absorptiometry (DXA) was used to determine abdominal fat percentage. The results indicate that the correlation between T-score and heel bone mineral density (BMD) for cortisone, as well as Z-score and heel BMD, is a linear relationship that has statistical significance P-value

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Abstract Dual-energy X-ray absorptiometry (DXA) represents the gold standard for measuring bone mineral density (BMD). However, its size and bulkiness limit its use in mass screening. Portable and easily accessible instruments are more suitable for this purpose. We conducted a study to assess the repeatability, sensitivity, accuracy, and validation of a new ultrasound densitometer for the calcaneus (OsteoSys BeeTLe) compared to standard DXA. BMD (g/cm2) was measured at the femoral and lumbar spine levels using DXA (Discovery Acclaim (Hologic, Waltham, MA, USA) or Lunar Prodigy (GE Healthcare, Madison, WI, USA) devices). Bone Quality Index (BQI, a dimensionless measure of bone quality derived from measures of SOS [Speed Of Sound] and BUA [broadband ultrasound attenuation]) was measured with OsteoSys BeeTLe. The Bland–Altman test and simple linear regression were used to evaluate the association between values measured with the two instruments. Additionally, the ability of the T-score calculated with BeeTLe to identify patients with previous osteoporotic fractures was tested using ROC curves. A total of 201 patients (94.5% females) with a mean age of 62.1 ± 10.2 were included in the study. The BeeTLe instrument showed a coefficient of variation (CV, in 75 repeated measurements) of 1.21%, which was not statistically different from the CV of DXA (1.20%). We found a significant association between BQI and BMD at the femoral neck (r2 = 0.500, p

Background: In patients with locally advanced breast cancer (LABC) receiving neoadjuvant chemotherapy (NAC), quantitative ultrasound (QUS) radiomics can predict final responses early within 4 of 16-18 weeks of treatment. The current study was planned to study the feasibility of a QUS-radiomics model-guided adaptive chemotherapy. Methods: The phase 2 open-label randomized controlled trial included patients with LABC planned for NAC. Patients were randomly allocated in 1:1 ratio to a standard arm or experimental arm stratified by hormonal receptor status. All patients were planned for standard anthracycline and taxane-based NAC as decided by their medical oncologist. Patients underwent QUS imaging using a clinical ultrasound device before the initiation of NAC and after the 1st and 4th weeks of treatment. A support vector machine-based radiomics model developed from an earlier cohort of patients was used to predict treatment response at the 4th week of NAC. In the standard arm, patients continued to receive planned chemotherapy with the treating oncologists blinded to results. In the experimental arm, the QUS-based prediction was conveyed to the responsible oncologist, and any changes to the planned chemotherapy for predicted non-responders were made by the responsible oncologist. All patients underwent surgery following NAC, and the final response was evaluated based on histopathological examination. Results: Between June 2018 and July 2021, 60 patients were accrued in the study arm, with 28 patients in each arm available for final analysis. In patients without a change in chemotherapy regimen (53 of 56 patients total), the QUSradiomics model at week 4 of NAC that was used demonstrated an accuracy of 97%, respectively, in predicting the final treatment response. Seven patients were predicted to be non-responders (observational arm (n=2), experimental arm (n=5)). Three of 5 non-responders in the experimental arm had chemotherapy regimens adapted with an early initiation of taxane therapy or chemotherapy intensification, or early surgery and ended up as responders on final evaluation. Conclusion: The study demonstrates the feasibility of QUS-radiomics adapted guided NAC for patients with breast cancer. The ability of a QUS-based model in the early prediction of treatment response was prospectively validated in the current study. [ABSTRACT FROM AUTHOR]

Dual-energy X-ray absorptiometry (DXA) represents the gold standard for measuring bone mineral density (BMD). However, its size and bulkiness limit its use in mass screening. Portable and easily accessible instruments are more suitable for this purpose. We conducted a study to assess the repeatability, sensitivity, accuracy, and validation of a new ultrasound densitometer for the calcaneus (OsteoSys BeeTLe) compared to standard DXA. BMD (g/cm2) was measured at the femoral and lumbar spine levels using DXA (Discovery Acclaim (Hologic, Waltham, MA, USA) or Lunar Prodigy (GE Healthcare, Madison, WI, USA) devices). Bone Quality Index (BQI, a dimensionless measure of bone quality derived from measures of SOS [Speed Of Sound] and BUA [broadband ultrasound attenuation]) was measured with OsteoSys BeeTLe. The Bland–Altman test and simple linear regression were used to evaluate the association between values measured with the two instruments. Additionally, the ability of the T-score calculated with BeeTLe to identify patients with previous osteoporotic fractures was tested using ROC curves. A total of 201 patients (94.5% females) with a mean age of 62.1 ± 10.2 were included in the study. The BeeTLe instrument showed a coefficient of variation (CV, in 75 repeated measurements) of 1.21%, which was not statistically different from the CV of DXA (1.20%). We found a significant association between BQI and BMD at the femoral neck (r2 = 0.500, p < 0.0001), total femur (r2 = 0.545, p < 0.0001), and lumbar spine (r2 = 0.455, p < 0.0001). T-scores bias were 0.215 (SD 0.876), 0.021 (SD 0.889) and 0.523 (SD 0.092), for femoral neck, total hip and lumbar spine respectively. AUC for discriminating fracture and non-fractured patients were not significantly different with OsteoSys BeeTLe and standard DXA. In this preliminary study, BeeTLe, a new point-of-care ultrasound densitometer, demonstrated good repeatability and performance similar to DXA. Therefore, its use can be proposed in screening for osteoporosis. [ABSTRACT FROM AUTHOR]

BackgroundIn patients with locally advanced breast cancer (LABC) receiving neoadjuvant chemotherapy (NAC), quantitative ultrasound (QUS) radiomics can predict final responses early within 4 of 16-18 weeks of treatment. The current study was planned to study the feasibility of a QUS-radiomics model-guided adaptive chemotherapy.MethodsThe phase 2 open-label randomized controlled trial included patients with LABC planned for NAC. Patients were randomly allocated in 1:1 ratio to a standard arm or experimental arm stratified by hormonal receptor status. All patients were planned for standard anthracycline and taxane-based NAC as decided by their medical oncologist. Patients underwent QUS imaging using a clinical ultrasound device before the initiation of NAC and after the 1st and 4th weeks of treatment. A support vector machine-based radiomics model developed from an earlier cohort of patients was used to predict treatment response at the 4th week of NAC. In the standard arm, patients continued to receive planned chemotherapy with the treating oncologists blinded to results. In the experimental arm, the QUS-based prediction was conveyed to the responsible oncologist, and any changes to the planned chemotherapy for predicted non-responders were made by the responsible oncologist. All patients underwent surgery following NAC, and the final response was evaluated based on histopathological examination.ResultsBetween June 2018 and July 2021, 60 patients were accrued in the study arm, with 28 patients in each arm available for final analysis. In patients without a change in chemotherapy regimen (53 of 56 patients total), the QUS-radiomics model at week 4 of NAC that was used demonstrated an accuracy of 97%, respectively, in predicting the final treatment response. Seven patients were predicted to be non-responders (observational arm (n=2), experimental arm (n=5)). Three of 5 non-responders in the experimental arm had chemotherapy regimens adapted with an early initiation of taxane therapy or chemotherapy intensification, or early surgery and ended up as responders on final evaluation.ConclusionThe study demonstrates the feasibility of QUS-radiomics adapted guided NAC for patients with breast cancer. The ability of a QUS-based model in the early prediction of treatment response was prospectively validated in the current study.Clinical trial registrationclinicaltrials.gov, ID NCT04050228.

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The aim of study is to measure osteoporosis in the right foot at the heel (calcaneus) by using the quantitative ultrasound (QUS) technique. It was measured (SOS, BUA, BQI, T-score and Z-score). While the usage of the DXA technique is measure the tissue thickness. Osteoporosis represents low bone mineral density (BMD). The heel of the foot (calcaneus) uses in QUS measurements because it contains a high ratio of trabecular bone. T-score is the predominant the diagnosis of osteoporosis used for adults, men and women over 50 years. From T-score can be to know the ratio of BMD, according to the WHO a T-score can be classified (Normal, Osteopenia and Osteoporosis). Age group 31-40 years was T-score for both sex (-0.667) is meaning (Normal bone). In the age group, 51-60 years was T-score (-1.60) for both sex represents (osteopenia). While age group 71-80 years T-score for females (-2.56) and males (-3.30), means that both males and females have (osteoporosis). P-value

The aim of this study was to measure osteoporosis in the right heel bone. A total of 123 Iraqi men and women with low back pain (LBP) participated in the study (18 males and 105 females). Quantitative Ultrasound (QUS) was used to assess osteoporosis, speed of sound (SOS), broadband ultrasound attenuation (BUA), and calcaneus bone quality index (BQI). A dual x-ray absorptiometry (DXA) was used to determine tissue thickness, fracture risk factor, and abdominal fat percentage. The results indicate that SOS was 1495.43±18.780 m/sec. Participants had a Z-score of -1.10±1.56. The fracture risk factor for participants was 1.622± 1.90 when DXA measurements were taken. Low back pain measurements revealed that the age group between 51-60 years had the highest prevalence. The correlation between the T-score and the calcaneal SOS is a linear relationship with a P-value of 0.0001. When we examine the relationship between the Z-score and the calcaneal BUA, we see that it is linear and statistically significant (P-value less than 0.0001). The correlations between calcaneal BQI and BMI, as well as between calcaneal BUA and tissue thickness, were found to be statistically insignificant (P-value = 0.8 and 0.8, respectively). The correlation between calcaneal SOS and abdominal fat percent appears to be statistically significant (P-value=0.05) (linear correlation is weak).

Objectives: Accurately measuring the attenuation coefficient (AC) of reference phantoms is critical in clinical applications of quantitative ultrasound. Phantom AC measurement requires proper compensation of membrane transmission loss. Conventional methods require separate membrane samples to obtain membrane transmission loss. Unfortunately, separate membrane samples are often unavailable. A pulse‐echo approach is proposed herein to compensate for membrane transmission loss without requiring separate membrane samples. Methods: The proposed method consists of the following steps. First, the insertion loss, caused by phantom attenuation and membrane transmission loss, is measured. Second, the membrane reflection coefficient is measured. Third, the unknown acoustic parameters of the membrane and phantom material are estimated by fitting theoretical reflection coefficient to the measured one. Finally, the fitted parameters are used to estimate membrane transmission loss and phantom AC. The proposed method was validated through k‐Wave simulations and phantom experiments. Experimental AC measurements were repeated on 5 distinct phantoms by 2 operators to assess the repeatability and reproducibility of the proposed method. Five transducers were used to cover a broad bandwidth (0.7–16 MHz). Results: The acquired AC in the simulations had a maximum error of 0.06 dB/cm‐MHz for simulated phantom AC values ranging from 0.5 to 1 dB/cm‐MHz. The acquired AC in the experiments had a maximum error of 0.045 dB/cm‐MHz for phantom AC values ranging from 0.28 to 1.48 dB/cm‐MHz. Good repeatability and cross‐operator reproducibility were observed with a mean coefficient of variation below 0.054. Conclusion: The proposed method simplifies phantom AC measurement while providing satisfactory accuracy and precision. [ABSTRACT FROM AUTHOR]

Simple Summary: At present, quantitative ultrasound (QUS) is increasingly utilized in cancer imaging. Compared to other imaging modalities that take several days to weeks to assess treatment effectiveness, QUS can provide a rapid treatment evaluation. Its implementation has been documented in characterizing benign versus malignant breast lesions, assessing lymph nodes, predicting and monitoring tumor response, etc. Both preclinical and clinical studies have confirmed that changes in QUS parameters are directly correlated with tissue microstructural alterations. QUS parameters and textural analyses have widely been used to predict and monitor neoadjuvant chemotherapy (NAC) response in locally advanced breast cancer (LABC) patients. Thus, QUS methods have emerged as one of the most useful imaging techniques for the management of several tumor types. Quantitative ultrasound (QUS) is a non-invasive novel technique that allows treatment response monitoring. Studies have shown that QUS backscatter variables strongly correlate with changes observed microscopically. Increases in cell death result in significant alterations in ultrasound backscatter parameters. In particular, the parameters related to scatterer size and scatterer concentration tend to increase in relation to cell death. The use of QUS in monitoring tumor response has been discussed in several preclinical and clinical studies. Most of the preclinical studies have utilized QUS for evaluating cell death response by differentiating between viable cells and dead cells. In addition, clinical studies have incorporated QUS mostly for tissue characterization, including classifying benign versus malignant breast lesions, as well as responder versus non-responder patients. In this review, we highlight some of the important findings of previous preclinical and clinical studies and expand the applicability and therapeutic benefits of QUS in clinical settings. We summarized some recent clinical research advances in ultrasound-based radiomics analysis for monitoring and predicting treatment response and characterizing benign and malignant breast lesions. We also discuss current challenges, limitations, and future prospects of QUS-radiomics. [ABSTRACT FROM AUTHOR]

Attenuation maps or measurements based on the local attenuation coefficient slope (ACS) in quantitative ultrasound (QUS) have shown potential for the diagnosis of liver steatosis. In liver cancers, tissue abnormalities and tumors detected using ACS are also of interest to provide new image contrast to clinicians. Current phantom-based approaches have the limitation of assuming a comparable speed of sound between the reference phantom and insonified tissues. Moreover, these methods present the inconvenience for operators to acquire data on phantoms and patients. The main goal was to alleviate these drawbacks by proposing a methodology for constructing phantom-free regularized (PF-R) local ACS maps and investigate the performance in both homogeneous and heterogeneous media. The proposed method was tested on two tissue-mimicking media with different ACS constructed as homogeneous phantoms, side-by-side and top-to-bottom phantoms, and inclusion phantoms with different attenuations. Moreover, an in vivo proof-of-concept was performed on healthy, steatotic, and cancerous human liver datasets. Modifications brought to previous works include: 1) a linear interpolation of the power spectrum in the log scale; 2) the relaxation of the underlying hypothesis on the diffraction factor; 3) a generalization to nonhomogeneous local ACS; and 4) an adaptive restriction of frequencies to a more reliable range than the usable frequency range. Regularization was formulated as a generalized least absolute shrinkage and selection operator (LASSO), and a variant of the Bayesian information criterion (BIC) was applied to estimate the Lagrangian multiplier on the LASSO constraint. In addition, we evaluated the proposed algorithm when applying median filtering before and after regularization. Tests conducted showed that the PF-R yielded robust results in all tested conditions, suggesting potential for additional validation as a diagnosis method. [ABSTRACT FROM AUTHOR]

Previous studies suggest that saturated fat (SFA) intake may negatively impact on bone. However, few human studies on the topic exist. Women and men aged 31-46 years from the Cardiovascular Risk in Young Finns study attended the peripheral quantitative computed tomography and ultrasound bone measurements in 2008 (n = 1884-1953, ~ 56% women). In addition, fracture diagnoses in 1980-2018 were searched for the national health care registers and 431 participants had at least one fracture. Food consumption was gathered with the 48-h dietary recall interviews and food frequency questionnaire in 1980-2007. In the present study, radial, tibial, and calcaneal bone traits, and fractures were examined relative to the long-term intake of SFA. No consistent associations were seen between bone outcomes and SFA intake that would have replicated in both women and men. The only evidence for differential distributions was seen in cortical density and cortical-to-total area ratio at the radial shaft, and speed of sound at the calcaneus, which were 0.1-0.4% higher in women in the lowest tertile of SFA intake compared with the highest tertile. In addition, among men, the odds ratio (OR) of fractures was greater in the second (OR 1.86, 95% confidence interval (CI) 1.03-3.33) and third tertile of SFA intake (OR 2.45, 95% CI 1.38-4.36) compared with the lowest tertile, independently of many risk factors of osteoporosis. In this observational study, we found no robust evidence of the associations of dietary long-term SFA intake with bone outcomes. Therefore, additional studies are needed to confirm the association of dietary SFA with bone health in humans. [ABSTRACT FROM AUTHOR]

The use of guided wave ultrasonography as a means to assess cortical bone quality has been a significant practice in bone quantitative ultrasound for more than 20 years. In this article, the key developments within the technology of ultrasonic guided waves (UGW) in long bones during the past decade are documented. The covered topics include data acquisition configurations available for measuring bone guided waveforms, signal processing techniques applied to bone UGW, numerical modeling of ultrasonic wave propagation in cortical long bones, formulation of inverse approaches to extract bone properties from observed ultrasonic signals, and clinical studies to establish the technology’s application and efficacy. The review concludes by highlighting specific challenging problems and future research directions. In general, the primary purpose of this work is to provide a comprehensive overview of bone guided-wave ultrasound, especially for newcomers to this scientific field. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Education & Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of e & i Elektrotechnik und Informationstechnik is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There is growing interest in the relationship between chronic kidney disease (CKD) and fragility fracture risk. Bone mineral density (BMD) is a major determinant of bone strength, although its role as a predictor of fracture in advanced CKD and hemodialysis is still under debate. We aimed to further investigate surrogates of bone quality and their associations with muscle strength and fracture risk in hemodialysis. Multiple clinical risk factors for fracture and an estimated 10-year probability of fracture, BMD at lumbar spine and femur, trabecular bone score (TBS), X-ray vertebral morphometry, phalangeal bone quantitative ultrasonography (QUS), tibial pulse-echo ultrasonography (PEUS), and handgrip strength were evaluated in a setting of hemodialysis patients in treatment with acetate-free biofiltration (AFB) or bicarbonate hemodialysis. The bone ultrasound measurements, both at phalangeal and tibial sites, were significantly associated with lumbar and femoral DXA values. Handgrip strength was significantly associated with the 10-year probability of fracture (r = -0.57, p < 0.001 for major fractures and r = -0.53, p < 0.001 for hip fracture, respectively), with femur neck, total femur, and L1-L4 BMD values (r = 0.47, p = 0.04; r = 0.48, p = 0.02; r = 0.58, p = 0.007, respectively), with TBS at the lumbar spine (r = 0.71, p < 0.001) and with the phalangeal QUS measure of AD-SoS (r = 0.369, p = 0.023). In the hemodialysis group, 10 participants (24.3%) reported at least one morphometric vertebral fracture (Vfx); conversely, only six participants (15%) showed Vfx in the control group. In the hemodialysis group, participants with Vfx compared with participants without Vfx reported significantly different TBS, bone transmission time (BTT), cortical thickness, and handgrip strength (p < 0.05). At multiple regression analysis, by identifying as dependent variable the 10-year fracture risk for major fracture, after correcting for age, BMI, time since dialysis, AD-SoS, cortical bone thickness, and handgrip strength, only BTT (b = -15.21, SE = 5.91, p = 0.02) and TBS (b = -54.69, SE = 21.88, p = 0.02) turned out as independently associated with fracture risk. In conclusion, hemodialysis patients showed a higher fracture risk and lower surrogate indices of bone strength as TBS and QUS parameters. In this cohort of patients, handgrip strength measurements appeared to be a useful instrument to identify highfracture-risk subjects. [ABSTRACT FROM AUTHOR]

Introduction: Relationship of quantitative ultrasound (QUS) with high-resolution peripheral quantitative computed tomography (HR-pQCT), dual-energy X-ray absorptiometry (DXA), and bone-related biochemical markers was analyzed.Materials and Methods: The subjects were 480 individuals. Speed of sound (SOS) was measured by calcaneal QUS. Volumetric bone mineral density (vBMD) and microarchitecture of trabecular and cortical bone in the distal radius and tibia were assessed by HR-pQCT. Areal bone mineral density (aBMD) in the lumbar spine and proximal femur were measured by DXA. TRACP-5b, P1NP, 25 (OH) vitamin D, and pentosidine were evaluated by biochemical tests. The correlation of each parameter was analyzed for all subjects and by sex and age group.Results: QUS was moderately correlated with Tb.vBMD and Tb.BV/TV in the radius and tibia. No correlation was seen with Ct.vBMD or cortical porosity (Ct.Po). Although a correlation was seen with cortical thickness (Ct.Th) in the tibia in all subjects, no correlation was seen in women aged ≥ 60 years. QUS showed moderate correlations with aBMD in the proximal femur. Although moderate correlation was seen with aBMD in the lumbar spine in all subjects, no correlation was seen in subjects aged ≥ 60 years. No significant correlations were seen between QUS and biochemical markers.Conclusions: Moderate correlations were seen between QUS and Tb.vBMD and microarchitecture in the radius and tibia and aBMD of the proximal femur. On the other hand, practically no correlations were seen with Ct.vBMD or Ct.Po and the bone-related biochemical markers. Only in middle age, moderate correlations were seen with Ct.Th in the tibia and with aBMD of the lumbar spine. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Education & Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Quantitative ultrasound (QUS) aims to reveal information about the tissue microstructure using backscattered echo signals from clinical scanners. Among different QUS parameters, scatterer number density is an important property that can affect the estimation of other QUS parameters. Scatterer number density can be classified into high or low scatterer densities. If there are more than ten scatterers inside the resolution cell, the envelope data are considered as fully developed speckle (FDS) and, otherwise, as underdeveloped speckle (UDS). In conventional methods, the envelope data are divided into small overlapping windows (a strategy here we refer to as patching), and statistical parameters, such as SNR and skewness, are employed to classify each patch of envelope data. However, these parameters are system-dependent, meaning that their distribution can change by the imaging settings and patch size. Therefore, reference phantoms that have known scatterer number density are imaged with the same imaging settings to mitigate system dependency. In this article, we aim to segment regions of ultrasound data without any patching. A large dataset is generated, which has different shapes of scatterer number density and mean scatterer amplitude using a fast simulation method. We employ a convolutional neural network (CNN) for the segmentation task and investigate the effect of domain shift when the network is tested on different datasets with different imaging settings. Nakagami parametric image is employed for multitask learning to improve performance. Furthermore, inspired by the reference phantom methods in QUS, a domain adaptation stage is proposed, which requires only two frames of data from FDS and UDS classes. We evaluate our method for different experimental phantoms and in vivo data. [ABSTRACT FROM AUTHOR]

Aim and Objective: Our study's objective is to determine the level of awareness in postmenopausal women in Guwahati, Northeast part of India, using the Osteoporosis Health Belief Scale (OHBS). Settings and Design: Osteoporosis is the most common silent health problem in postmenopausal Indian women. An awareness level among this subset of women needs to study. The present study is based on a self-explanatory questionnaire. Methods: We conducted a self-explanatory questionnaire study on 2000 postmenopausal women in Guwahati, North East region of India. The bone mineral density (BMD) was measured using calcaneum Quantitative ultrasound (QUS) to assess BMD. Baseline characteristics were noted and analyzed. Results: The awareness level was noted only in757 (37.85%). Women with education level 12th standard and above have some awareness regarding osteoporosis. Conclusions: Based on the present study, we can conclude that there is a lack of awareness in postmenopausal women regarding osteoporosis in India's North-East region. This subset of women is unaware of the condition that can leads to fragility fracture if not address in time. The study emphasizes that health care professionals should conduct frequent awareness programs in the community to prevent this silent disease, and morbidities so arise from osteoporosis can be minimized.

Quantitative ultrasound (QUS) can reveal crucial information on tissue properties, such as scatterer density. If the scatterer density per resolution cell is above or below 10, the tissue is considered as fully developed speckle (FDS) or underdeveloped speckle (UDS), respectively. Conventionally, the scatterer density has been classified using estimated statistical parameters of the amplitude of backscattered echoes. However, if the patch size is small, the estimation is not accurate. These parameters are also highly dependent on imaging settings. In this article, we adapt convolutional neural network (CNN) architectures for QUS and train them using simulation data. We further improve the network’s performance by utilizing patch statistics as additional input channels. Inspired by deep supervision and multitask learning, we propose a second method to exploit patch statistics. We evaluate the networks using simulation data and experimental phantoms. We also compare our proposed methods with different classic and deep learning models and demonstrate their superior performance in the classification of tissues with different scatterer density values. The results also show that we are able to classify scatterer density in different imaging parameters with no need for a reference phantom. This work demonstrates the potential of CNNs in classifying scatterer density in ultrasound images. [ABSTRACT FROM AUTHOR]

Background: Osteoporosis in women is a serious health problem. The relationships between biochemical markers of bone turnover and bone mineral density (BMD) in women have been reported, but no study has examined relationships between tartrate-resistant acid phosphatase-5b (TRACP-5b) or bone-specific alkaline phosphatase (BAP) and bone mass measured by quantitative ultrasound (QUS) in Japanese post-menopausal women. Aim: To investigate the serum TRACP-5b and BAP levels and to determine their associations with the heel stiffness index measured by QUS in post-menopausal women. Subjects and methods: The subjects were 510 post-menopausal women who were invited to participate in periodic health examinations in 2011–2013 (the Unzen Study). The heel stiffness index (bone mass) was measured by QUS. Serum samples were collected and TRACP-5b and BAP levels were measured. Results: Multiple regression analysis showed that a higher log (TRACP-5b) was correlated with a lower stiffness index (p = 0.014) and log (BAP) was not correlated with stiffness index after adjusting for covariates (p = 0.136). Conclusion: Higher rates of bone resorption are associated with a lower stiffness index in Japanese post-menopausal women. These results may indicate that high bone resorption affects bone mass more than bone formation, resulting in a low bone mass.

Aim and Objective: Our study's objective is to determine the level of awareness in postmenopausal women in Guwahati, Northeast part of India, using the Osteoporosis Health Belief Scale (OHBS). Settings and Design: Osteoporosis is the most common silent health problem in postmenopausal Indian women. An awareness level among this subset of women needs to study. The present study is based on a self-explanatory questionnaire. Methods: We conducted a self-explanatory questionnaire study on 2000 postmenopausal women in Guwahati, North East region of India. The bone mineral density (BMD) was measured using calcaneum Quantitative ultrasound (QUS) to assess BMD. Baseline characteristics were noted and analyzed. Results: The awareness level was noted only in757 (37.85%). Women with education level 12th standard and above have some awareness regarding osteoporosis. Conclusions: Based on the present study, we can conclude that there is a lack of awareness in postmenopausal women regarding osteoporosis in India's North-East region. This subset of women is unaware of the condition that can leads to fragility fracture if not address in time. The study emphasizes that health care professionals should conduct frequent awareness programs in the community to prevent this silent disease, and morbidities so arise from osteoporosis can be minimized. [ABSTRACT FROM AUTHOR]

Introduction: The objectives of this study were to identify what is reflected in cortical speed of sound (cSOS) measured by a cortical quantitative ultrasound (cortical QUS) device we have developed, and to investigate cSOS measurements in healthy individuals and dialysis patients. Methods: The cSOS and the SOS were measured by cortical QUS and conventional QUS in 20 volunteers, and the correlations between these measurements and areal bone mineral density measured by dual-energy X-ray absorptiometry and bone microstructural parameters on high-resolution peripheral quantitative computed tomography were analyzed. The cSOS and the SOS were measured in 91 young adults (47 men, 44 women), 64 elderly people (30 men, 33 women), and 64 dialysis patients (33 men, 31 women). The period of hemodialysis and intact parathyroid hormoneevels were also investigated in the dialysis patients. Results: cSOS was correlated with cortical tissue mineral density (tibia: r = 0.74, radius: r = 0.72) on high-resolution peripheral quantitative computed tomography, reflecting the degree of minaralization and microporosity of cortical bone. There was no correlation with the thickness of cortical bone, suggesting that it measured the bone quality rather than bone mass. Elderly women had lower cSOS than young adults (3865 ± 74 vs 3971 ± 63 m/s, p < 0.01). Many of dialysis patients showed very low cSOS and it was related to higher intact parathyroid hormone levels (male: ß = −0.67, female: ß = −0.60). Conclusions: Our cortical QUS device is capable of evaluating the qualitative degradation of cortical bone, which cannot be assessed by conventional QUS, and its use in combination with conventional QUS may provide a better understanding of fracture risk. [ABSTRACT FROM AUTHOR]

Abstract This study aimed to characterize the relationship between the ratio of the length of the second and fourth fingers (2D:4D value) and the speed of sound of the calcaneus by quantitative ultrasound (QUS-SOS) in undergraduate female students. We recruited 138 young women with a mean age of 19.6 ± 1.4 years. The participants’ calcaneus QUS-SOS was measured using an ultrasound bone densitometer. We also measured the participants’ weight, height, and grip strength. A self-reported questionnaire was used to obtain information on participants’ secondary sexual characteristics, and exercise habits. The present study showed that the 2D:4D value of both hands was significantly correlated with the calcaneus QUS-SOS. The 2D:4D value of the left hand was also positively associated with the calcaneus QUS-SOS results in several respects. These findings suggest that the 2D:4D value may be useful for the screening of risk for a low bone quality in undergraduate female students.

The goal of this study was to develop an ultrasound (US) scatterer spacing estimation method using an enhanced cepstral analysis based on continuous wavelet transforms (CWTs). Simulations of backscattering media containing periodic and quasi-periodic scatterers were carried out to test the developed algorithm. Experimental data from HT-29 pellets and in vivo PC3 tumors were then used to estimate the mean scatterer spacing. For simulated media containing quasi-periodic scatterers at 1-mm and 100- $\mu \text{m}$ spacing with 5% positional variation, the developed algorithm yielded a spacing estimation error of ~1% for 25- and 55-MHz US pulses. The mean scatterer spacing of HT-29 cell pellets (31.97 $\mu \text{m}$) was within 3% of the spacing obtained from histology and agreed with the predicted spacing from simulations based on the same pellets for both frequencies. The agreement extended to in vivo PC3 tumors estimation of the spacing with a variance of 1.68% between the spacing derived from the tumor histology and the application of the CWT to the experimental results. The developed technique outperformed the traditional cepstral methods as it can detect nonprominent peaks from quasi-random scatterer configurations. This work can be potentially used to detect morphological tissue changes during normal development or disease treatment. [ABSTRACT FROM AUTHOR]

Summary: We compared the bone strength measured via quantitative computed tomography-based finite element method (QCT/FEM) between healthy adults with and without ossification of the posterior longitudinal ligament (OPLL). No statistically significant difference was observed in the bone strength between healthy adults with and without OPLL. Hyperostosis of the posterior longitudinal ligament in OPLL may not be associated with the systemic bone strength. Introduction: Although patients with OPLL have been reportedly associated with increased level of bone mineral density (BMD) using dual-energy X-ray absorptiometry (DXA), little is known about the bone strength in OPLL subjects. The aim of this study is to investigate the bone strength measured via QCT/FEM in healthy subjects with OPLL using the medical check-up data, including whole-body CT scans. Methods: We examined 796 participants (529 men and 267 women) who underwent CT scans in a single health center between January 2008 and May 2009. We identified OPLL in whole spine and divided the subjects into two groups: non-OPLL and OPLL groups. We calculated the predicted bone strength (PBS) of the proximal femur using QCT/FEM and examined the bone mineral status of the calcaneus using quantitative ultrasound (QUS). We compared the PBS and the QUS parameters between the non-OPLL and OPLL groups. Results: Seventy-four subjects (9.3%; 57 men and 17 women) were diagnosed with OPLL in the whole spine. The OPLL group was significantly older than the non-OPLL group. No statistically significant difference was observed in the PBS and the QUS parameters between the non-OPLL and OPLL groups in both sexes. Furthermore, no statistically significant difference was noted in the PBS and the QUS parameters between two groups in age- and gender-matched analysis. Conclusions: Our results suggest that hyperostosis of the posterior longitudinal ligament in OPLL may not be associated with bone strength and bone mineral status at the extremities. [ABSTRACT FROM AUTHOR]

The objective of this article is to demonstrate the feasibility of estimating the backscatter coefficient (BSC) using an in situ calibration source. Traditional methods of estimating the BSC in vivo using a reference phantom technique do not account for transmission losses due to intervening layers between the ultrasonic source and the tissue region to be interrogated, leading to increases in bias and variance of BSC-based estimates. To account for transmission losses, an in situ calibration approach is proposed. The in situ calibration technique employs a titanium sphere that is well-characterized ultrasonically, biocompatible, and embedded inside the sample. A set of experiments was conducted to evaluate the embedded titanium spheres as in situ calibration targets for BSC estimation. The first experiment quantified the backscattered signal strength from titanium spheres of three sizes: 0.5, 1, and 2 mm in diameter. The second set of experiments assessed the repeatability of BSC estimates from the titanium spheres and compared these BSCs to theory. The third set of experiments quantified the ability of the titanium bead to provide an in situ reference spectrum in the presence of a lossy layer on top of the sample. The final set of experiments quantified the ability of the bead to provide a calibration spectrum over multiple depths in the sample. All experiments were conducted using an L9-4/38 linear array connected to a SonixOne system. The strongest signal was observed from the 2-mm titanium bead with the signal-to-noise ratio (SNR) of 11.6 dB with respect to the background speckle. Using an analysis bandwidth of 2.5–5.5 MHz, the mean differences between the experimentally derived BSCs and BSCs derived from the Faran theory were 0.54 and 0.76 dB using the array and a single-element transducer, respectively. The BSCs estimated using the in situ calibration approach without the layer and with the layer and using the reference phantom approach with the layer were compared to the reference phantom approach without the layer present. The mean differences in BSCs were 0.15, 0.73, and −9.69 dB, respectively. The mean differences of the BSCs calculated from data blocks located at depths that were either 30 pulse lengths above or below the actual bead depth compared to the BSC calculated at bead depth were −1.55 and −1.48 dB, respectively. The results indicate that an in situ calibration target can account for overlaying tissue losses, thereby improving the robustness of BSC-based estimates. [ABSTRACT FROM AUTHOR]

Purpose: Long-term exposure to anti-epileptic drugs has been shown to decrease bone mineral density (BMD). The aim of this 7-year follow-up study was to explore changes in bone status, using quantitative ultrasound (QUS) and Dual-energy X-ray Absorptiometry (DXA) in adults with refractory epilepsy and intellectual disability (ID) residing at a long-term care facility. Both measurements can be challenging to conduct in this population.Methods: In 2009 and 2016, a total of 126 patients (18-79 years) underwent QUS of the heel and DXA of lumbar spine (LS) and hip (femoral neck (FN) and total hip (TH)). Subgroup analysis was performed for patients with (group A, n = 53) and without (group B, n = 73) bisphosphonate use during follow-up.Results: Overall, weak to moderate correlations between changes in DXA and QUS parameters were found. For group A, correlations varied from r = .31 to .59, whereas correlations did not exceed r = .40 in group B. Patients in group A showed a larger increase or a smaller decrease in BMD for all DXA regions during follow-up (p < .001 for ΔLS and ΔFN BMD, p = .001 for ΔTH BMD). For change in QUS parameters, no significant difference between groups was found.Conclusion: In this study we demonstrated the limited use of QUS in the monitoring of bone status in our study population. Although correlations between changes in QUS parameters and axial DXA are positive and mostly significant, QUS only explains little of the variability in DXA values and is inadequate for measuring treatment response in this population. [ABSTRACT FROM AUTHOR]

This article evaluated the repeatability and reproducibility (R&R) of quantitative ultrasound (QUS) biomarkers attenuation coefficient (AC) and backscatter coefficient (BSC) in transvaginal QUS reference phantoms for obstetric applications. Five phantoms were scanned by three sonographers according to the scanning protocol. Each sonographer scanned each phantom with four transvaginal transducers of the same model (MC9-4) and three probe cover types (latex cover, nonlatex cover, and no cover). The AC and BSC were estimated by using a reference phantom method. The R&R analysis was performed for the frequency-averaged AC and logBSC (= 10log10BSC) (5.4–5.8 MHz) by using three-factor random effects Analysis of Variance with interaction. The total R&R variabilities for AC and logBSC are small (AC: 0.042–0.065 dB/cm-MHz; logBSC: 0.50–0.68 dB), indicating high measurement precision. These values are small compared to the ranges of AC (0.28–0.99 dB/cm-MHz) and logBSC (−33.16 to −20.35 dB) of the five phantoms. The AC and logBSC biomarkers measured on transvaginal QUS phantoms using the reference phantom method are repeatable, and reproducible between sonographers, transducers, and probe covers. [ABSTRACT FROM AUTHOR]

Background: Osteoporosis in women is a serious health problem. The relationships between biochemical markers of bone turnover and bone mineral density (BMD) in women have been reported, but no study has examined relationships between tartrate-resistant acid phosphatase-5b (TRACP-5b) or bone-specific alkaline phosphatase (BAP) and bone mass measured by quantitative ultrasound (QUS) in Japanese post-menopausal women. Aim: To investigate the serum TRACP-5b and BAP levels and to determine their associations with the heel stiffness index measured by QUS in post-menopausal women. Subjects and methods: The subjects were 510 post-menopausal women who were invited to participate in periodic health examinations in 2011–2013 (the Unzen Study). The heel stiffness index (bone mass) was measured by QUS. Serum samples were collected and TRACP-5b and BAP levels were measured. Results: Multiple regression analysis showed that a higher log (TRACP-5b) was correlated with a lower stiffness index (p = 0.014) and log (BAP) was not correlated with stiffness index after adjusting for covariates (p = 0.136). Conclusion: Higher rates of bone resorption are associated with a lower stiffness index in Japanese post-menopausal women. These results may indicate that high bone resorption affects bone mass more than bone formation, resulting in a low bone mass. [ABSTRACT FROM AUTHOR]

Quantitative ultrasound (QUS) imaging methods, including elastography, echogenicity analysis, and speckle statistical modeling, are available from a single ultrasound (US) radio-frequency data acquisition. Since these US imaging methods provide complementary quantitative tissue information, characterization of carotid artery plaques may gain from their combination. Sixty-six patients with symptomatic ($n = 26$) and asymptomatic ($n = 40$) carotid atherosclerotic plaques were included in the study. Of these, 31 underwent magnetic resonance imaging (MRI) to characterize plaque vulnerability and quantify plaque components. US radio-frequency data sequence acquisitions were performed on all patients and were used to compute noninvasive vascular US elastography and other QUS features. Additional QUS features were computed from three types of images: homodyned-K (HK) parametric maps, Nakagami parametric maps, and log-compressed B-mode images. The following six classification tasks were performed: detection of 1) a small area of lipid; 2) a large area of lipid; 3) a large area of calcification; 4) the presence of a ruptured fibrous cap; 5) differentiation of MRI-based classification of nonvulnerable carotid plaques from neovascularized or vulnerable ones; and 6) confirmation of symptomatic versus asymptomatic patients. Feature selection was first applied to reduce the number of QUS parameters to a maximum of three per classification task. A random forest machine learning algorithm was then used to perform classifications. Areas under receiver-operating curves (AUCs) were computed with a bootstrap method. For all tasks, statistically significant higher AUCs were achieved with features based on elastography, HK parametric maps, and B-mode gray levels, when compared to elastography alone or other QUS alone ($p < 0.001$). For detection of a large area of lipid, the combination yielding the highest AUC (0.90, 95% CI 0.80–0.92, $p < 0.001$) was based on elastography, HK, and B-mode gray-level features. To detect a large area of calcification, the highest AUC (0.95, 95% CI 0.94–0.96, $p < 0.001$) was based on HK and B-mode gray level features. For other tasks, AUCs varied between 0.79 and 0.97. None of the best combinations contained Nakagami features. This study shows the added value of combining different features computed from a single US acquisition with machine learning to characterize carotid artery plaques. [ABSTRACT FROM AUTHOR]

One of the main limitations of ultrasound imaging is that image quality and interpretation depend on the skill of the user and the experience of the clinician. Quantitative ultrasound (QUS) methods provide objective, system-independent estimates of tissue properties, such as acoustic attenuation and backscattering properties of tissue, which are valuable as objective tools for both diagnosis and intervention. Accurate and precise estimation of these properties requires correct compensation for intervening tissue attenuation. Prior attempts to estimate intervening-tissue attenuation based on minimizing cost functions that compared backscattered echo data to models have resulted in limited precision and accuracy. To overcome these limitations, in this paper, we incorporate the prior information of piecewise continuity of QUS parameters as a regularization term into our cost function. We further propose to calculate this cost function using dynamic programming (DP), a computationally efficient optimization algorithm that finds the global optimum. Our results on tissue-mimicking phantoms show that DP substantially outperforms a published least squares method in terms of both estimation bias and variance. [ABSTRACT FROM AUTHOR]

Objective: A computer-assisted technology has recently been proposed for the assessment of therapeutic responses to neoadjuvant chemotherapy in patients with locally advanced breast cancer (LABC). The system, however, extracted features from individual scans in a tumor irrespective of its relation to the other scans of the same patient, ignoring the volumetric information. This study addresses this problem by introducing a novel engineered texton-based method in order to account for volumetric information in the design of textural descriptors to represent tumor scans. Methods: A noninvasive computer-aided-theragnosis (CAT) system was developed by employing multiparametric QUS spectral and backscatter coefficient maps. The proceeding was composed of two subdictionaries: one built on the “pretreatment” and another on “week ${N}$ ” scans, where ${N}$ was 1, 4, or 8. The learned dictionary of each patient was subsequently used to compute the model (histogram of textons) for each scan of the patient. Advanced machine learning techniques including a kernel-based dissimilarity measure to estimate the distances between “pretreatment” and “mid-treatment” scans as an indication of treatment effectiveness, learning from imbalanced data, and supervised learning were subsequently employed on the texton-based features. Results: The performance of the CAT system was tested using statistical tests of significance and leave-one-subject-out (LOSO) classification on 56 LABC patients. The proposed texton-based CAT system indicated significant differences in changes between the responding and nonresponding patient populations and achieved high accuracy, sensitivity, and specificity in discriminating between the two patient groups early after the start of treatment, i.e., on weeks 1 and 4 of several months of treatment. Specifically, the CAT system achieved the area under curve of 0.81, 0.83, and 0.85 on weeks 1, 4, and 8, respectively. Conclusion: The proposed texton-based CAT system accounted for the volumetric information in “pretreatment” and “mid-treatment” scans of each patient. It was demonstrated that this attribute of the CAT system could boost its performance compared to the cases that the features were extracted from solely individual scans. [ABSTRACT FROM AUTHOR]

Dual X-ray absorptiometry (DXA) is used to diagnose osteoporosis. On the other hand, quantitative ultrasound (QUS) is widely used to assess bone density as part of medical screening as it is relatively inexpensive and easy to perform. Current QUS devices do not share precise ultrasound-related parameters, such as frequency, waveform, beam pattern, transient response, definition of propagation time, definition of degree of attenuation, and precise measurement site, resulting in different measurements across models. The Japan Osteoporosis Society established a QUS Standardization Committee in 2007 to investigate standardization of speed of sound (SOS) and broadband ultrasonic attenuation (BUA) measurements to resolve this issue. The committee came up with a formula to convert SOS and BUA values yielded by each model available in Japan. This has made it possible to convert QUS measurements from different models into standardized values, greatly improving the effectiveness of QUS measurements. [ABSTRACT FROM AUTHOR]

Choosing an appropriate dynamic range (DR) for acquiring radio frequency (RF) data from a high-frequency-ultrasound (HFU) system is challenging because signals can vary greatly in amplitude as a result of focusing and attenuation effects. In addition, quantitative ultrasound (QUS) results are altered by saturated data. In this paper, the effects of saturation on QUS estimates of effective scatterer diameter (ESD) and effective acoustic concentration (EAC) were quantified using simulated and experimental RF data. Experimental data were acquired from 69 dissected human lymph nodes using a single-element transducer with a 26-MHz center frequency. Artificially saturated signals ( xc) were produced by thresholding the original unsaturated RF echo signals. Saturation severity was expressed using a quantity called saturate-signal-to-noise ratio (SSNR). Results indicated that saturation has little effect on ESD estimates. However, EAC estimates decreased significantly with decreasing SSNR. An EAC correction algorithm exploiting a linear relationship between EAC values over a range of SSNR values and l^1 -norm of xc (i.e., the sum of absolute values of the true RF echo signal) is developed. The maximal errors in EAC estimates resulting from saturation were −8.05, −3.59, and −0.93 dB/mm3 with the RF echo signals thresholded to keep 5, 6, and 7-bit from the original 8-bit DR, respectively. The EAC correction algorithm reduced maximal errors to −3.71, −0.89, and −0.26 dB/mm3 when signals were thresholded at 5, 6, and 7-bit, respectively. [ABSTRACT FROM AUTHOR]

Disc degeneration is associated with premature ageing of intervertebral discs (IVD) and a gradual degradation of the nucleus pulposus (NP) biomechanical properties. The objective of this study is to investigate whether quantitative ultrasound (QUS) technique can be used to determine the speed of sound (SOS) in the NP and to correlate SOS with histological measurements. The ultrasonic measurements are realized with a 3.5MHz focused monoelement transducer used in echographic mode. The value of the interspecimen variability of SOS is significantly superior than the reproducibility of the measurements, which indicates that the technique is sensitive to variations of the material properties of the NP. A significant correlation between SOS values and the percentage of physaliphorous cells ratios is obtained () when considering all samples. QUS can be useful to assess the biomechanical properties of the IVD, which may be useful in the context of tissue engineering applications. [ABSTRACT FROM AUTHOR]

The purposes of this paper were to evaluate the correlation between ultrasonic power spectrum and bone density and to extract the effectiveness of parameters from power spectrum for evaluating bone density. A total of 50 persons 24–72 years of age were recruited. All study participants underwent bone mineral density (BMD) measurements of the lumbar spine (vertebral levels L1–L4). The participants also underwent calcaneal measurements to determine ultrasonic power spectrum with central frequencies of 0.5 MHz. Three parameters from normalized power spectrum, called principle frequency (PF), frequency band (FB), and amplitude for principle frequency (APF), were chosen and be evaluated the correlation with the lumbar spine BMD. The correlation coefficient of PF, FB and APF with BMD was r = −0.48 ( p < 0.001), r = 0.48 ( p < 0.001), and r = −0.71 ( p < 0.001), respectively. The results showed that the correlation between APF and BMD was better than the correlation among PF, FB and BMD, and APF have a significant correlation with BMD. In conclusion, the correlations among the parameters of ultrasonic power spectrum and BMD are significant, and especially APF performs better than PF and FB in evaluating bone density of participants. These results suggest that ultrasonic power spectrum may contain substantial information not already contained in BUA and SOS. A multiple regression model including all three QUS variables was somewhat more predictive of BMD than a model including only BUA and SOS. [ABSTRACT FROM AUTHOR]

Purpose: Bone quantity, as determined by the current gold standard, dual energy X-ray absorptiometry (DXA), through measured areal bone mineral density (aBMD), is subject to positive biases if bone strontium levels are high. This is of particular concern for populations administered strontium-based compounds for the treatment of osteoporosis. This study investigated the dependence of bone mineral density (BMD) determinations, and associated ultrasound-determined indices, obtained by quantitative ultrasound (QUS), on bone strontium content using a new generation of trabecular bone-mimicking phantoms. Purpose: Bone quantity, as determined by the current gold standard, dual energy X-ray absorptiometry (DXA), through measured areal bone mineral density (aBMD), is subject to positive biases if bone strontium levels are high. This is of particular concern for populations administered strontium-based compounds for the treatment of osteoporosis. This study investigated the dependence of bone mineral density (BMD) determinations, and associated ultrasound-determined indices, obtained by quantitative ultrasound (QUS), on bone strontium content using a new generation of trabecular bone-mimicking phantoms. Results: Both the clinical system and the research QUS systems showed a strong dependency between BMD and BUA, indicating a potential for QUS to be used as a means of estimating BMD (p = 0.001). SOS was found to have no correlation to BMD (p = 0.546). There was no correlation observed between BUA and increasing bone strontium concentrations for the research (p = 0.749) and clinical (p = 0.609) QUS systems. Similarly, no dependency was observed between the SOS and bone strontium levels up to 2.5 mol/mol [Sr/(Sr+Ca)]% for the research (p = 0.862) and clinical (p = 0.481) QUS systems. No effect on the QUI values was observed with changing strontium levels with either research (p = 0.939) or clinical QUS systems (p = 0.931). A Bland-Altman analysis showed that there was a clear offset in determined QUI values for both systems but they are in agreement with one another. Results: Both the clinical system and the research QUS systems showed a strong dependency between BMD and BUA, indicating a potential for QUS to be used as a means of estimating BMD (p = 0.001). SOS was found to have no correlation to BMD (p = 0.546). There was no correlation observed between BUA and increasing bone strontium concentrations for the research (p = 0.749) and clinical (p = 0.609) QUS systems. Similarly, no dependency was observed between the SOS and bone strontium levels up to 2.5 mol/mol [Sr/(Sr+Ca)]% for the research (p = 0.862) and clinical (p = 0.481) QUS systems. No effect on the QUI values was observed with changing strontium levels with either research (p = 0.939) or clinical QUS systems (p = 0.931). A Bland-Altman analysis showed that there was a clear offset in determined QUI values for both systems but they are in agreement with one another. [ABSTRACT FROM AUTHOR]

Purpose: Our objective was to evaluate the dynamic time window method (DTWM) for the measurement of speed of sound (SOS) at the 1/3 distal radius in 10 human subjects in vivo. DTWM, which is based on our proprietary probe, is a new method for obtaining the accurate time of flight (TOF) of the first arriving signal (FAS). Method: This study compared DTWM with three conventional methods, i.e., threshold value method, first of maxima, and zero-crossing method, for the measurement of TOF of FAS. Results: The highest correlation between SOS and bone mineral density (BMD) was found in the 10 human subjects using DTWM ( R = 0.81, p < 0.005) rather than the three conventional methods ( R = 0.37-0.41, p > 0.05). The individual short-term coefficient of variation (CV, from 0.07 to 0.27) and Root-Mean-Square (RMS) of the average CV (CV, 0.18) were used to evaluate the reproducibility of our method (DTWM). Conclusion: Despite the small population, the results suggest that DTWM improves the accuracy of recognition of SOS in vivo, and might be applied to optimize the clinical assessment of long cortical bone osteoporosis and fracture risk profile. [ABSTRACT FROM AUTHOR]

Quantitative ultrasound (QUS) techniques using radiofrequency (RF) backscattered signals have been used for tissue characterization of numerous organ systems. One approach is to use the magnitude and frequency dependence of backscatter echoes to quantify tissue structures. Another approach is to use first-order statistical properties of the echo envelope as a signature of the tissue microstructure. We propose a unification of these QUS concepts. For this purpose, a mixture of homodyned K-distributions is introduced to model the echo envelope, together with an estimation method and a physical interpretation of its parameters based on the echo signal spectrum. In particular, the total, coherent and diffuse signal powers related to the proposed mixture model are expressed explicitly in terms of the structure factor previously studied to describe the backscatter coefficient (BSC). Then, this approach is illustrated in the context of red blood cell (RBC) aggregation. It is experimentally shown that the total, coherent and diffuse signal powers are determined by a structural parameter of the spectral Structure Factor Size and Attenuation Estimator. A two-way repeated measures ANOVA test showed that attenuation (p-value of 0.077) and attenuation compensation (p-value of 0.527) had no significant effect on the diffuse to total power ratio. These results constitute a further step in understanding the physical meaning of first-order statistics of ultrasound images and their relations to QUS techniques. The proposed unifying concepts should be applicable to other biological tissues than blood considering that the structure factor can theoretically model any spatial distribution of scatterers. [ABSTRACT FROM PUBLISHER]