Comparison of longitudinal excursion of a nerve-phantom model using quantitative ultrasound imaging and motion analysis system methods: A convergent validity study.

PubMed

Paquette, Philippe; El Khamlichi, Youssef; Lamontagne, Martin; Higgins, Johanne; Gagnon, Dany H

2017-08-01

Quantitative ultrasound imaging is gaining popularity in research and clinical settings to measure the neuromechanical properties of the peripheral nerves such as their capability to glide in response to body segment movement. Increasing evidence suggests that impaired median nerve longitudinal excursion is associated with carpal tunnel syndrome. To date, psychometric properties of longitudinal nerve excursion measurements using quantitative ultrasound imaging have not been extensively investigated. This study investigates the convergent validity of the longitudinal nerve excursion by comparing measures obtained using quantitative ultrasound imaging with those determined with a motion analysis system. A 38-cm long rigid nerve-phantom model was used to assess the longitudinal excursion in a laboratory environment. The nerve-phantom model, immersed in a 20-cm deep container filled with a gelatin-based solution, was moved 20 times using a linear forward and backward motion. Three light-emitting diodes were used to record nerve-phantom excursion with a motion analysis system, while a 5-cm linear transducer allowed simultaneous recording via ultrasound imaging. Both measurement techniques yielded excellent association ( r  = 0.99) and agreement (mean absolute difference between methods = 0.85 mm; mean relative difference between methods = 7.48 %). Small discrepancies were largely found when larger excursions (i.e. > 10 mm) were performed, revealing slight underestimation of the excursion by the ultrasound imaging analysis software. Quantitative ultrasound imaging is an accurate method to assess the longitudinal excursion of an in vitro nerve-phantom model and appears relevant for future research protocols investigating the neuromechanical properties of the peripheral nerves.

Bone measurements of infants with hyperbilirubinemia by quantitative ultrasound: the influence of phototherapy.

PubMed

Arıkan, Fatma İnci; Kara, Semra; Bilgin, Hüseyin; Özkan, Fatma; Bilge, Yıldız Dallar

2017-07-01

The purpose of the current study was to investigate the possible effects of phototherapy on bone status of term infants evaluated by measurement of tibial bone speed of sound (SOS). The phototherapy group (n = 30) consisted of children who had undergone phototherapy for at least 24 h and the control group (n = 30) comprised children who had not received phototherapy. Blood samples were obtained from all infants for serum calcium, phosphorus, magnesium, alkaline phosphatase, parathyroid hormone and vitamin D concentrations. The left tibial quantitative ultrasound (QUS) measurements were performed using a commercial device. There was no statistically significant difference between phototherapy-exposed and nonexposed infants in terms of Ca, P, ALP, PTH and vitamin D levels. Comparison of bone SOS between the phototherapy-exposed and control group revealed no statistically difference. Also, no significant difference in Z-score for SOS was observed between those with or without exposure. The data of our study indicate that phototherapy treatment has no impact on bone status in the hyperbilirubinemic infants. Although there is no statistically significant evidence of an excess risk of bone damage following phototherapy, studies with larger sample sizes and longer duration of follow-up are needed to gain a better understanding of its effects.

Quantitative Evaluation of Atherosclerotic Plaque Using Ultrasound Tissue Characterization.

NASA Astrophysics Data System (ADS)

Yigiter, Ersin

Evaluation of therapeutic methods directed toward interrupting and/or delaying atherogenesis is impeded by the lack of a reliable, non-invasive means for monitoring progression or regression of disease. The ability to characterize the predominant component of plaque may be very valuable in the study of this disease's natural history. The earlier the lesion, the more likely is lipid to be the predominant component. Progression of plaque is usually by way of overgrowth of fibrous tissues around the fatty pool. Calcification is usually a feature of the older or complicated lesion. To explore the feasibility of using ultrasound to characterize plaque we have conducted measurements of the acoustical properties of various atherosclerotic lesions found in freshly excised samples of human abdominal aorta. Our objective has been to determine whether or not the acoustical properties of plaque correlate with the type and/or chemical composition of plaque and, if so, to define a measurement scheme which could be done in-vivo and non-invasively. Our current data base consists of individual tissue samples from some 200 different aortas. Since each aorta yields between 10 to 30 tissue samples for study, we have data on some 4,468 different lesions or samples. Measurements of the acoustical properties of plaque were found to correlate well with the chemical composition of plaque. In short, measurements of impedance and attenuation seem sufficient to classify plaque as to type and to composition. Based on the in-vitro studies, the parameter of attenuation was selected as a means of classifying the plaque. For these measurements, an intravascular ultrasound scanner was modified according to our specifications. Signal processing algorithms were developed which would analyze the complex ultrasound waveforms and estimate tissue properties such as attenuation. Various methods were tried to estimate the attenuation from the pulse-echo backscattered signal. Best results were obtained by

Quantitative Contrast-Enhanced Ultrasound Parameters in Crohn Disease: Their Role in Disease Activity Determination With Ultrasound.

PubMed

Medellin-Kowalewski, Alexandra; Wilkens, Rune; Wilson, Alexandra; Ruan, Ji; Wilson, Stephanie R

2016-01-01

The primary objective of our study was to examine the association between contrast-enhanced ultrasound (CEUS) parameters and established gray-scale ultrasound with color Doppler imaging (CDI) for the determination of disease activity in patients with Crohn disease. Our secondary objective was to develop quantitative time-signal intensity curve thresholds for disease activity. One hundred twenty-seven patients with Crohn disease underwent ultrasound with CDI and CEUS. Reviewers graded wall thickness, inflammatory fat, and mural blood flow as showing remission or inflammation (mild, moderate, or severe). If both gray-scale ultrasound and CDI predicted equal levels of disease activity, the studies were considered concordant. If ultrasound images suggested active disease not supported by CDI findings, the ultrasound results for disease activity were indeterminate. Time-signal intensity curves from CEUS were acquired with calculation of peak enhancement (PE), and AUCs. Interobserver variation and associations between PE and ultrasound parameters were examined. Multiclass ROC analysis was used to develop CEUS thresholds for activity. Ninety-six (76%) studies were concordant, 19 of which showed severe disease, and 31 (24%) studies were indeterminate. Kappa analyses revealed good interobserver agreement on grades for CDI (κ = 0.76) and ultrasound (κ = 0.80) assessments. PE values on CEUS and wall thickness showed good association with the Spearman rank correlation coefficient for the entire population (ρ = 0.62, p < 0.01) and for the concordant group (ρ = 0.70, p < 0.01). Multiclass ROC analyses of the concordant group using wall thickness alone as the reference standard showed cutoff points of 18.2 dB for differentiating mild versus moderate activity (sensitivity, 89.0% and specificity, 87.0%) and 23.0 dB for differentiating moderate versus severe (sensitivity, 90% and specificity, 86.8%). Almost identical cutoff points were observed when using ultrasound global

Quantitative assessment of tumor angiogenesis using real-time motion-compensated contrast-enhanced ultrasound imaging

PubMed Central

Pysz, Marybeth A.; Guracar, Ismayil; Foygel, Kira; Tian, Lu; Willmann, Jürgen K.

2015-01-01

Purpose To develop and test a real-time motion compensation algorithm for contrast-enhanced ultrasound imaging of tumor angiogenesis on a clinical ultrasound system. Materials and methods The Administrative Institutional Panel on Laboratory Animal Care approved all experiments. A new motion correction algorithm measuring the sum of absolute differences in pixel displacements within a designated tracking box was implemented in a clinical ultrasound machine. In vivo angiogenesis measurements (expressed as percent contrast area) with and without motion compensated maximum intensity persistence (MIP) ultrasound imaging were analyzed in human colon cancer xenografts (n = 64) in mice. Differences in MIP ultrasound imaging signal with and without motion compensation were compared and correlated with displacements in x- and y-directions. The algorithm was tested in an additional twelve colon cancer xenograft-bearing mice with (n = 6) and without (n = 6) anti-vascular therapy (ASA-404). In vivo MIP percent contrast area measurements were quantitatively correlated with ex vivo microvessel density (MVD) analysis. Results MIP percent contrast area was significantly different (P < 0.001) with and without motion compensation. Differences in percent contrast area correlated significantly (P < 0.001) with x- and y-displacements. MIP percent contrast area measurements were more reproducible with motion compensation (ICC = 0.69) than without (ICC = 0.51) on two consecutive ultrasound scans. Following anti-vascular therapy, motion-compensated MIP percent contrast area significantly (P = 0.03) decreased by 39.4 ± 14.6 % compared to non-treated mice and correlated well with ex vivo MVD analysis (Rho = 0.70; P = 0.05). Conclusion Real-time motion-compensated MIP ultrasound imaging allows reliable and accurate quantification and monitoring of angiogenesis in tumors exposed to breathing-induced motion artifacts. PMID:22535383

Quantitative assessment of tumor angiogenesis using real-time motion-compensated contrast-enhanced ultrasound imaging.

PubMed

Pysz, Marybeth A; Guracar, Ismayil; Foygel, Kira; Tian, Lu; Willmann, Jürgen K

2012-09-01

To develop and test a real-time motion compensation algorithm for contrast-enhanced ultrasound imaging of tumor angiogenesis on a clinical ultrasound system. The Administrative Institutional Panel on Laboratory Animal Care approved all experiments. A new motion correction algorithm measuring the sum of absolute differences in pixel displacements within a designated tracking box was implemented in a clinical ultrasound machine. In vivo angiogenesis measurements (expressed as percent contrast area) with and without motion compensated maximum intensity persistence (MIP) ultrasound imaging were analyzed in human colon cancer xenografts (n = 64) in mice. Differences in MIP ultrasound imaging signal with and without motion compensation were compared and correlated with displacements in x- and y-directions. The algorithm was tested in an additional twelve colon cancer xenograft-bearing mice with (n = 6) and without (n = 6) anti-vascular therapy (ASA-404). In vivo MIP percent contrast area measurements were quantitatively correlated with ex vivo microvessel density (MVD) analysis. MIP percent contrast area was significantly different (P < 0.001) with and without motion compensation. Differences in percent contrast area correlated significantly (P < 0.001) with x- and y-displacements. MIP percent contrast area measurements were more reproducible with motion compensation (ICC = 0.69) than without (ICC = 0.51) on two consecutive ultrasound scans. Following anti-vascular therapy, motion-compensated MIP percent contrast area significantly (P = 0.03) decreased by 39.4 ± 14.6 % compared to non-treated mice and correlated well with ex vivo MVD analysis (Rho = 0.70; P = 0.05). Real-time motion-compensated MIP ultrasound imaging allows reliable and accurate quantification and monitoring of angiogenesis in tumors exposed to breathing-induced motion artifacts.

Factors that influence bone mass of healthy children and adolescents measured by quantitative ultrasound at the hand phalanges: a systematic review☆

PubMed Central

Krahenbühl, Tathyane; Gonçalves, Ezequiel Moreira; Costa, Eduardo Tavares; Barros, Antonio de Azevedo

2014-01-01

Objective: To analyze the main factors that influence bone mass in children and teenagers assessed by quantitative ultrasound (QUS) of the phalanges. Data source: A systematic literature review was performed according to the PRISMA method with searches in databases Pubmed/Medline, SciELO and Bireme for the period 2001-2012, in English and Portuguese languages, using the keywords: children, teenagers, adolescent, ultrasound finger phalanges, quantitative ultrasound of phalanges, phalangeal quantitative ultrasound. Data synthesis: 21 articles were included. Girls had, in QUS, Amplitude Dependent Speed of Sound (AD-SoS) values higher than boys during pubertal development. The values of the parameters of QUS of the phalanges and dual-energy X-ray Absorptiometry (DXA) increased with the increase of the maturational stage. Anthropometric variables such as age, weight, height, body mass index (BMI), lean mass showed positive correlations with the values of QUS of the phalanges. Physical activity has also been shown to be positively associated with increased bone mass. Factors such as ethnicity, genetics, caloric intake and socioeconomic profile have not yet shown a conclusive relationship and need a larger number of studies. Conclusions: QUS of the phalanges is a method used to evaluate the progressive acquisition of bone mass during growth and maturation of individuals in school phase, by monitoring changes that occur with increasing age and pubertal stage. There were mainly positive influences variables of sex, maturity, height, weight and BMI, with similar data when compared to the gold standard method, the DXA. PMID:25479860

Cross-sectional evaluation of electrical impedance myography and quantitative ultrasound for the assessment of Duchenne muscular dystrophy in a clinical trial setting.

PubMed

Rutkove, Seward B; Geisbush, Tom R; Mijailovic, Aleksandar; Shklyar, Irina; Pasternak, Amy; Visyak, Nicole; Wu, Jim S; Zaidman, Craig; Darras, Basil T

2014-07-01

Electrical impedance myography and quantitative ultrasound are two noninvasive, painless, and effort-independent approaches for assessing neuromuscular disease. Both techniques have potential to serve as useful biomarkers in clinical trials in Duchenne muscular dystrophy. However, their comparative sensitivity to disease status and how they relate to one another are unknown. We performed a cross-sectional analysis of electrical impedance myography and quantitative ultrasound in 24 healthy boys and 24 with Duchenne muscular dystrophy, aged 2 to 14 years with trained research assistants performing all measurements. Three upper and three lower extremity muscles were studied unilaterally in each child, and the data averaged for each individual. Both electrical impedance myography and quantitative ultrasound differentiated healthy boys from those with Duchenne muscular dystrophy (P < 0.001 for both). Quantitative ultrasound values correlated with age in Duchenne muscular dystrophy boys (rho = 0.45; P = 0.029), whereas electrical impedance myography did not (rho = -0.31; P = 0.14). However, electrical impedance myography phase correlated with age in healthy boys (rho = 0.51; P = 0.012), whereas quantitative ultrasound did not (rho = -0.021; P = 0.92). In Duchenne muscular dystrophy boys, electrical impedance myography phase correlated with the North Star Ambulatory Assessment (rho = 0.65; P = 0.022); quantitative ultrasound revealed a near-significant association (rho = -0.56; P = 0.060). The two technologies trended toward a moderate correlation with one another in the Duchenne muscular dystrophy cohort but not in the healthy group (rho = -0.40; P = 0.054 and rho = -0.32; P = 0.13, respectively). Electrical impedance myography and quantitative ultrasound are complementary modalities for the assessment of boys with Duchenne muscular dystrophy; further study and application of these two modalities alone or in combination in a longitudinal fashion are warranted. Copyright

Quantitative evaluation of the fetal cerebellar vermis using the median view on three-dimensional ultrasound.

PubMed

Zhao, Dan; Liu, Wei; Cai, Ailu; Li, Jingyu; Chen, Lizhu; Wang, Bing

2013-02-01

The purpose of this study was to investigate the effectiveness for quantitative evaluation of cerebellar vermis using three-dimensional (3D) ultrasound and to establish a nomogram for Chinese fetal vermis measurements during gestation. Sonographic examinations were performed in normal fetuses and in cases suspected of the diagnosis of vermian rotation. 3D median planes were obtained with both OMNIVIEW and tomographic ultrasound imaging. Measurements of the cerebellar vermis were highly correlated between two-dimensional and 3D median planes. The diameter of the cerebellar vermis follows growth approximately predicted by the quadratic regression equation. The normal vermis was almost parallel to the brain stem, with the average angle degree to be <2° in normal fetuses. The average angle degree of the 9 cases of vermian rotation was >5°. Three-dimensional median planes are obtained more easily than two-dimensional ones, and allow accurate measurements of the cerebellar vermis. The 3D approach may enable rapid assessment of fetal cerebral anatomy in standard examination. Measurements of cerebellar vermis may provide a quantitative index for prenatal diagnosis of posterior fossa malformations. © 2012 John Wiley & Sons, Ltd.

Quantitative Ultrasound Imaging Using Acoustic Backscatter Coefficients.

NASA Astrophysics Data System (ADS)

Boote, Evan Jeffery

Current clinical ultrasound scanners render images which have brightness levels related to the degree of backscattered energy from the tissue being imaged. These images offer the interpreter a qualitative impression of the scattering characteristics of the tissue being examined, but due to the complex factors which affect the amplitude and character of the echoed acoustic energy, it is difficult to make quantitative assessments of scattering nature of the tissue, and thus, difficult to make precise diagnosis when subtle disease effects are present. In this dissertation, a method of data reduction for determining acoustic backscatter coefficients is adapted for use in forming quantitative ultrasound images of this parameter. In these images, the brightness level of an individual pixel corresponds to the backscatter coefficient determined for the spatial position represented by that pixel. The data reduction method utilized rigorously accounts for extraneous factors which affect the scattered echo waveform and has been demonstrated to accurately determine backscatter coefficients under a wide range of conditions. The algorithms and procedures used to form backscatter coefficient images are described. These were tested using tissue-mimicking phantoms which have regions of varying scattering levels. Another phantom has a fat-mimicking layer for testing these techniques under more clinically relevant conditions. Backscatter coefficient images were also formed of in vitro human liver tissue. A clinical ultrasound scanner has been adapted for use as a backscatter coefficient imaging platform. The digital interface between the scanner and the computer used for data reduction are described. Initial tests, using phantoms are presented. A study of backscatter coefficient imaging of in vivo liver was performed using several normal, healthy human subjects.

Quantitative Analysis of the Cervical Texture by Ultrasound and Correlation with Gestational Age.

PubMed

Baños, Núria; Perez-Moreno, Alvaro; Migliorelli, Federico; Triginer, Laura; Cobo, Teresa; Bonet-Carne, Elisenda; Gratacos, Eduard; Palacio, Montse

2017-01-01

Quantitative texture analysis has been proposed to extract robust features from the ultrasound image to detect subtle changes in the textures of the images. The aim of this study was to evaluate the feasibility of quantitative cervical texture analysis to assess cervical tissue changes throughout pregnancy. This was a cross-sectional study including singleton pregnancies between 20.0 and 41.6 weeks of gestation from women who delivered at term. Cervical length was measured, and a selected region of interest in the cervix was delineated. A model to predict gestational age based on features extracted from cervical images was developed following three steps: data splitting, feature transformation, and regression model computation. Seven hundred images, 30 per gestational week, were included for analysis. There was a strong correlation between the gestational age at which the images were obtained and the estimated gestational age by quantitative analysis of the cervical texture (R = 0.88). This study provides evidence that quantitative analysis of cervical texture can extract features from cervical ultrasound images which correlate with gestational age. Further research is needed to evaluate its applicability as a biomarker of the risk of spontaneous preterm birth, as well as its role in cervical assessment in other clinical situations in which cervical evaluation might be relevant. © 2016 S. Karger AG, Basel.

Quantitative head ultrasound measurements to determine thresholds for preterm neonates requiring interventional therapies following intraventricular hemorrhage

NASA Astrophysics Data System (ADS)

Kishimoto, Jessica; Fenster, Aaron; Salehi, Fateme; Romano, Walter; Lee, David S. C.; de Ribaupierre, Sandrine

2016-04-01

Dilation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage (IVH). This post hemorrhagic ventricle dilation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure and without treatment, can lead to death. Clinically, 2D ultrasound (US) through the fontanelles ('soft spots') of the patients are serially acquired to monitor the progression of the ventricle dilation. These images are used to determine when interventional therapies such as needle aspiration of the built up cerebrospinal fluid (CSF) ('ventricle tap', VT) might be indicated for a patient; however, quantitative measurements of the growth of the ventricles are often not performed. There is no consensus on when a neonate with PHVD should have an intervention and often interventions are performed after the potential for brain damage is quite high. Previously we have developed and validated a 3D US system to monitor the progression of ventricle volumes (VV) in IVH patients. We will describe the potential utility of quantitative 2D and 3D US to monitor and manage PHVD in neonates. Specifically, we will look to determine image-based measurement thresholds for patients who will require VT in comparison to patients with PHVD who resolve without intervention. Additionally, since many patients who have an initial VT will require subsequent interventions, we look at the potential for US to determine which PHVD patients will require additional VT after the initial one has been performed.

Quantitative assessment of acoustic intensity in the focused ultrasound field using hydrophone and infrared imaging.

PubMed

Yu, Ying; Shen, Guofeng; Zhou, Yufeng; Bai, Jingfeng; Chen, Yazhu

2013-11-01

With the popularity of ultrasound therapy in clinics, characterization of the acoustic field is important not only to the tolerability and efficiency of ablation, but also for treatment planning. A quantitative method was introduced to assess the intensity distribution of a focused ultrasound beam using a hydrophone and an infrared camera with no prior knowledge of the acoustic and thermal parameters of the absorber or the configuration of the array elements. This method was evaluated in both theoretical simulations and experimental measurements. A three-layer model was developed to calculate the acoustic field in the absorber, the absorbed acoustic energy during the sonication and the consequent temperature elevation. Experiments were carried out to measure the acoustic pressure with the hydrophone and the temperature elevation with the infrared camera. The percentage differences between the derived results and the simulation are <4.1% for on-axis intensity and <21.1% for -6-dB beam width at heating times up to 360 ms in the focal region of three phased-array ultrasound transducers using two different absorbers. The proposed method is an easy, quick and reliable approach to calibrating focused ultrasound transducers with satisfactory accuracy. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Quantitative shear wave ultrasound elastography: initial experience in solid breast masses

PubMed Central

2010-01-01

Introduction Shear wave elastography is a new method of obtaining quantitative tissue elasticity data during breast ultrasound examinations. The aims of this study were (1) to determine the reproducibility of shear wave elastography (2) to correlate the elasticity values of a series of solid breast masses with histological findings and (3) to compare shear wave elastography with greyscale ultrasound for benign/malignant classification. Methods Using the Aixplorer® ultrasound system (SuperSonic Imagine, Aix en Provence, France), 53 solid breast lesions were identified in 52 consecutive patients. Two orthogonal elastography images were obtained of each lesion. Observers noted the mean elasticity values in regions of interest (ROI) placed over the stiffest areas on the two elastography images and a mean value was calculated for each lesion. A sub-set of 15 patients had two elastography images obtained by an additional operator. Reproducibility of observations was assessed between (1) two observers analysing the same pair of images and (2) findings from two pairs of images of the same lesion taken by two different operators. All lesions were subjected to percutaneous biopsy. Elastography measurements were correlated with histology results. After preliminary experience with 10 patients a mean elasticity cut off value of 50 kilopascals (kPa) was selected for benign/malignant differentiation. Greyscale images were classified according to the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS). BI-RADS categories 1-3 were taken as benign while BI-RADS categories 4 and 5 were classified as malignant. Results Twenty-three benign lesions and 30 cancers were diagnosed on histology. Measurement of mean elasticity yielded an intraclass correlation coefficient of 0.99 for two observers assessing the same pairs of elastography images. Analysis of images taken by two independent operators gave an intraclass correlation coefficient of 0.80. Shear

Quantitative shear wave ultrasound elastography: initial experience in solid breast masses.

PubMed

Evans, Andrew; Whelehan, Patsy; Thomson, Kim; McLean, Denis; Brauer, Katrin; Purdie, Colin; Jordan, Lee; Baker, Lee; Thompson, Alastair

2010-01-01

Shear wave elastography is a new method of obtaining quantitative tissue elasticity data during breast ultrasound examinations. The aims of this study were (1) to determine the reproducibility of shear wave elastography (2) to correlate the elasticity values of a series of solid breast masses with histological findings and (3) to compare shear wave elastography with greyscale ultrasound for benign/malignant classification. Using the Aixplorer® ultrasound system (SuperSonic Imagine, Aix en Provence, France), 53 solid breast lesions were identified in 52 consecutive patients. Two orthogonal elastography images were obtained of each lesion. Observers noted the mean elasticity values in regions of interest (ROI) placed over the stiffest areas on the two elastography images and a mean value was calculated for each lesion. A sub-set of 15 patients had two elastography images obtained by an additional operator. Reproducibility of observations was assessed between (1) two observers analysing the same pair of images and (2) findings from two pairs of images of the same lesion taken by two different operators. All lesions were subjected to percutaneous biopsy. Elastography measurements were correlated with histology results. After preliminary experience with 10 patients a mean elasticity cut off value of 50 kilopascals (kPa) was selected for benign/malignant differentiation. Greyscale images were classified according to the American College of Radiology (ACR) Breast Imaging Reporting and Data System (BI-RADS). BI-RADS categories 1-3 were taken as benign while BI-RADS categories 4 and 5 were classified as malignant. Twenty-three benign lesions and 30 cancers were diagnosed on histology. Measurement of mean elasticity yielded an intraclass correlation coefficient of 0.99 for two observers assessing the same pairs of elastography images. Analysis of images taken by two independent operators gave an intraclass correlation coefficient of 0.80. Shear wave elastography versus

Noninvasive Quantitative Imaging of Collagen Microstructure in Three-Dimensional Hydrogels Using High-Frequency Ultrasound

PubMed Central

Mercado, Karla P.; Helguera, María; Hocking, Denise C.

2015-01-01

Collagen I is widely used as a natural component of biomaterials for both tissue engineering and regenerative medicine applications. The physical and biological properties of fibrillar collagens are strongly tied to variations in collagen fiber microstructure. The goal of this study was to develop the use of high-frequency quantitative ultrasound to assess collagen microstructure within three-dimensional (3D) hydrogels noninvasively and nondestructively. The integrated backscatter coefficient (IBC) was employed as a quantitative ultrasound parameter to detect, image, and quantify spatial variations in collagen fiber density and diameter. Collagen fiber microstructure was varied by fabricating hydrogels with different collagen concentrations or polymerization temperatures. IBC values were computed from measurements of the backscattered radio-frequency ultrasound signals collected using a single-element transducer (38-MHz center frequency, 13–47 MHz bandwidth). The IBC increased linearly with increasing collagen concentration and decreasing polymerization temperature. Parametric 3D images of the IBC were generated to visualize and quantify regional variations in collagen microstructure throughout the volume of hydrogels fabricated in standard tissue culture plates. IBC parametric images of corresponding cell-embedded collagen gels showed cell accumulation within regions having elevated collagen IBC values. The capability of this ultrasound technique to noninvasively detect and quantify spatial differences in collagen microstructure offers a valuable tool to monitor the structural properties of collagen scaffolds during fabrication, to detect functional differences in collagen microstructure, and to guide fundamental research on the interactions of cells and collagen matrices. PMID:25517512

Noninvasive Quantitative Imaging of Collagen Microstructure in Three-Dimensional Hydrogels Using High-Frequency Ultrasound.

PubMed

Mercado, Karla P; Helguera, María; Hocking, Denise C; Dalecki, Diane

2015-07-01

Collagen I is widely used as a natural component of biomaterials for both tissue engineering and regenerative medicine applications. The physical and biological properties of fibrillar collagens are strongly tied to variations in collagen fiber microstructure. The goal of this study was to develop the use of high-frequency quantitative ultrasound to assess collagen microstructure within three-dimensional (3D) hydrogels noninvasively and nondestructively. The integrated backscatter coefficient (IBC) was employed as a quantitative ultrasound parameter to detect, image, and quantify spatial variations in collagen fiber density and diameter. Collagen fiber microstructure was varied by fabricating hydrogels with different collagen concentrations or polymerization temperatures. IBC values were computed from measurements of the backscattered radio-frequency ultrasound signals collected using a single-element transducer (38-MHz center frequency, 13-47 MHz bandwidth). The IBC increased linearly with increasing collagen concentration and decreasing polymerization temperature. Parametric 3D images of the IBC were generated to visualize and quantify regional variations in collagen microstructure throughout the volume of hydrogels fabricated in standard tissue culture plates. IBC parametric images of corresponding cell-embedded collagen gels showed cell accumulation within regions having elevated collagen IBC values. The capability of this ultrasound technique to noninvasively detect and quantify spatial differences in collagen microstructure offers a valuable tool to monitor the structural properties of collagen scaffolds during fabrication, to detect functional differences in collagen microstructure, and to guide fundamental research on the interactions of cells and collagen matrices.

3-D Quantitative Dynamic Contrast Ultrasound for Prostate Cancer Localization.

PubMed

Schalk, Stefan G; Huang, Jing; Li, Jia; Demi, Libertario; Wijkstra, Hessel; Huang, Pintong; Mischi, Massimo

2018-04-01

To investigate quantitative 3-D dynamic contrast-enhanced ultrasound (DCE-US) and, in particular 3-D contrast-ultrasound dispersion imaging (CUDI), for prostate cancer detection and localization, 43 patients referred for 10-12-core systematic biopsy underwent 3-D DCE-US. For each 3-D DCE-US recording, parametric maps of CUDI-based and perfusion-based parameters were computed. The parametric maps were divided in regions, each corresponding to a biopsy core. The obtained parameters were validated per biopsy location and after combining two or more adjacent regions. For CUDI by correlation (r) and for the wash-in time (WIT), a significant difference in parameter values between benign and malignant biopsy cores was found (p < 0.001). In a per-prostate analysis, sensitivity and specificity were 94% and 50% for r, and 53% and 81% for WIT. Based on these results, it can be concluded that quantitative 3-D DCE-US could aid in localizing prostate cancer. Therefore, we recommend follow-up studies to investigate its value for targeting biopsies. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Quantitative ultrasound measurements of bone quality in female adolescents with idiopathic scoliosis compared to normal controls.

PubMed

Du, Qing; Zhou, Xuan; Li, Jian A; He, Xiao H; Liang, Ju P; Zhao, Li; Yang, Xiao Y; Chen, Nan; Zhang, Shu X; Chen, Pei J

2015-01-01

The aims of this study were to compare the speed-of-sound (SOS) between adolescent idiopathic scoliosis (AIS) patients and controls using quantitative ultrasound examination and to further analyze the relationship between the SOS and curve type, curve magnitude, maturation status and Risser's sign in AIS patients compared to controls. Seventy-eight female AIS patients and 58 healthy female controls 10 to 16 years of age were recruited to participate. Quantitative ultrasound measurements were performed at the non-dominant distal end of the radius. The standard method for estimating the SOS and z-score was used. Comparisons were made between the SOS values and z-score in AIS patients and age-matched Asian adolescents. The SOS values of the patients were significantly lower than the controls (P < .01). The percentage of cases with low bone quality was 25% in the entire AIS sample. The prevalence of low bone quality in AIS patients was 20.5%. However, there were no correlations between the SOS and types of scoliosis (P > .05). The SOS values among different severity groups were significant, particularly between the 10° to 19° and 20° to 39° groups as well as between 10° to 19° and ≥40° groups. However, there was no significant correlation between the SOS and Cobb angles. Significant correlations were also found between the pre- and post-menarchy status in patients. There was a significant difference in the SOS values for different Rissers' signs (P < .05). Compared to nonscoliotic controls, subjects with AIS had a generally lower SOS, indicating lower bone quality. The age, Risser's sign, or maturation status, may have an effect on the bone quality; however, the curve type and magnitude do not affect the bone quality. The results of this study indicate that slower bone maturation may affect the bone quality in adolescents with AIS. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

Fuzzy logic algorithm for quantitative tissue characterization of diffuse liver diseases from ultrasound images.

PubMed

Badawi, A M; Derbala, A S; Youssef, A M

1999-08-01

Computerized ultrasound tissue characterization has become an objective means for diagnosis of liver diseases. It is difficult to differentiate diffuse liver diseases, namely cirrhotic and fatty liver by visual inspection from the ultrasound images. The visual criteria for differentiating diffused diseases are rather confusing and highly dependent upon the sonographer's experience. This often causes a bias effects in the diagnostic procedure and limits its objectivity and reproducibility. Computerized tissue characterization to assist quantitatively the sonographer for the accurate differentiation and to minimize the degree of risk is thus justified. Fuzzy logic has emerged as one of the most active area in classification. In this paper, we present an approach that employs Fuzzy reasoning techniques to automatically differentiate diffuse liver diseases using numerical quantitative features measured from the ultrasound images. Fuzzy rules were generated from over 140 cases consisting of normal, fatty, and cirrhotic livers. The input to the fuzzy system is an eight dimensional vector of feature values: the mean gray level (MGL), the percentile 10%, the contrast (CON), the angular second moment (ASM), the entropy (ENT), the correlation (COR), the attenuation (ATTEN) and the speckle separation. The output of the fuzzy system is one of the three categories: cirrhosis, fatty or normal. The steps done for differentiating the pathologies are data acquisition and feature extraction, dividing the input spaces of the measured quantitative data into fuzzy sets. Based on the expert knowledge, the fuzzy rules are generated and applied using the fuzzy inference procedures to determine the pathology. Different membership functions are developed for the input spaces. This approach has resulted in very good sensitivities and specificity for classifying diffused liver pathologies. This classification technique can be used in the diagnostic process, together with the history

Measurement of tissue viscoelasticity with ultrasound

NASA Astrophysics Data System (ADS)

Greenleaf, J. F.; Alizad, A.

2017-02-01

Tissue properties such as elasticity and viscosity have been shown to be related to such tissue conditions as contraction, edema, fibrosis, and fat content among others. Magnetic Resonance Elastography has shown outstanding ability to measure the elasticity and in some cases the viscosity of tissues, especially in the liver, providing the ability to stage fibrotic liver disease similarly to biopsy. We discuss ultrasound methods of measuring elasticity and viscosity in tissues. Many of these methods are becoming widely available in the extant ultrasound machines distributed throughout the world. Some of the methods to be discussed are in the developmental stage. The advantages of the ultrasound methods are that the imaging instruments are widely available and that many of the viscoelastic measurements can be made during a short addition to the normal ultrasound examination time. In addition, the measurements can be made by ultrasound repetitively and quickly allowing evaluation of dynamic physiologic function in circumstances such as muscle contraction or artery relaxation. Measurement of viscoelastic tissue mechanical properties will become a consistent part of clinical ultrasound examinations in our opinion.

Objective measurement of accommodative biometric changes using ultrasound biomicroscopy

PubMed Central

Ramasubramanian, Viswanathan; Glasser, Adrian

2015-01-01

PURPOSE To demonstrate that ultrasound biomicroscopy (UBM) can be used for objective quantitative measurements of anterior segment accommodative changes. SETTING College of Optometry, University of Houston, Houston, Texas, USA. DESIGN Prospective cross-sectional study. METHODS Anterior segment biometric changes in response to 0 to 6.0 diopters (D) of accommodative stimuli in 1.0 D steps were measured in eyes of human subjects aged 21 to 36 years. Imaging was performed in the left eye using a 35 MHz UBM (Vumax) and an A-scan ultrasound (A-5500) while the right eye viewed the accommodative stimuli. An automated Matlab image-analysis program was developed to measure the biometry parameters from the UBM images. RESULTS The UBM-measured accommodative changes in anterior chamber depth (ACD), lens thickness, anterior lens radius of curvature, posterior lens radius of curvature, and anterior segment length were statistically significantly (P < .0001) linearly correlated with accommodative stimulus amplitudes. Standard deviations of the UBM-measured parameters were independent of the accommodative stimulus demands (ACD 0.0176 mm, lens thickness 0.0294 mm, anterior lens radius of curvature 0.3350 mm, posterior lens radius of curvature 0.1580 mm, and anterior segment length 0.0340 mm). The mean difference between the A-scan and UBM measurements was −0.070 mm for ACD and 0.166 mm for lens thickness. CONCLUSIONS Accommodating phakic eyes imaged using UBM allowed visualization of the accommodative response, and automated image analysis of the UBM images allowed reliable, objective, quantitative measurements of the accommodative intraocular biometric changes. PMID:25804579

Review of Quantitative Ultrasound: Envelope Statistics and Backscatter Coefficient Imaging and Contributions to Diagnostic Ultrasound.

PubMed

Oelze, Michael L; Mamou, Jonathan

2016-02-01

Conventional medical imaging technologies, including ultrasound, have continued to improve over the years. For example, in oncology, medical imaging is characterized by high sensitivity, i.e., the ability to detect anomalous tissue features, but the ability to classify these tissue features from images often lacks specificity. As a result, a large number of biopsies of tissues with suspicious image findings are performed each year with a vast majority of these biopsies resulting in a negative finding. To improve specificity of cancer imaging, quantitative imaging techniques can play an important role. Conventional ultrasound B-mode imaging is mainly qualitative in nature. However, quantitative ultrasound (QUS) imaging can provide specific numbers related to tissue features that can increase the specificity of image findings leading to improvements in diagnostic ultrasound. QUS imaging can encompass a wide variety of techniques including spectral-based parameterization, elastography, shear wave imaging, flow estimation, and envelope statistics. Currently, spectral-based parameterization and envelope statistics are not available on most conventional clinical ultrasound machines. However, in recent years, QUS techniques involving spectral-based parameterization and envelope statistics have demonstrated success in many applications, providing additional diagnostic capabilities. Spectral-based techniques include the estimation of the backscatter coefficient (BSC), estimation of attenuation, and estimation of scatterer properties such as the correlation length associated with an effective scatterer diameter (ESD) and the effective acoustic concentration (EAC) of scatterers. Envelope statistics include the estimation of the number density of scatterers and quantification of coherent to incoherent signals produced from the tissue. Challenges for clinical application include correctly accounting for attenuation effects and transmission losses and implementation of QUS on

Review of quantitative ultrasound: envelope statistics and backscatter coefficient imaging and contributions to diagnostic ultrasound

PubMed Central

Oelze, Michael L.; Mamou, Jonathan

2017-01-01

Conventional medical imaging technologies, including ultrasound, have continued to improve over the years. For example, in oncology, medical imaging is characterized by high sensitivity, i.e., the ability to detect anomalous tissue features, but the ability to classify these tissue features from images often lacks specificity. As a result, a large number of biopsies of tissues with suspicious image findings are performed each year with a vast majority of these biopsies resulting in a negative finding. To improve specificity of cancer imaging, quantitative imaging techniques can play an important role. Conventional ultrasound B-mode imaging is mainly qualitative in nature. However, quantitative ultrasound (QUS) imaging can provide specific numbers related to tissue features that can increase the specificity of image findings leading to improvements in diagnostic ultrasound. QUS imaging techniques can encompass a wide variety of techniques including spectral-based parameterization, elastography, shear wave imaging, flow estimation and envelope statistics. Currently, spectral-based parameterization and envelope statistics are not available on most conventional clinical ultrasound machines. However, in recent years QUS techniques involving spectral-based parameterization and envelope statistics have demonstrated success in many applications, providing additional diagnostic capabilities. Spectral-based techniques include the estimation of the backscatter coefficient, estimation of attenuation, and estimation of scatterer properties such as the correlation length associated with an effective scatterer diameter and the effective acoustic concentration of scatterers. Envelope statistics include the estimation of the number density of scatterers and quantification of coherent to incoherent signals produced from the tissue. Challenges for clinical application include correctly accounting for attenuation effects and transmission losses and implementation of QUS on clinical

Quantitative 3D high resolution transmission ultrasound tomography: creating clinically relevant images (Conference Presentation)

NASA Astrophysics Data System (ADS)

Wiskin, James; Klock, John; Iuanow, Elaine; Borup, Dave T.; Terry, Robin; Malik, Bilal H.; Lenox, Mark

2017-03-01

There has been a great deal of research into ultrasound tomography for breast imaging over the past 35 years. Few successful attempts have been made to reconstruct high-resolution images using transmission ultrasound. To this end, advances have been made in 2D and 3D algorithms that utilize either time of arrival or full wave data to reconstruct images with high spatial and contrast resolution suitable for clinical interpretation. The highest resolution and quantitative accuracy result from inverse scattering applied to full wave data in 3D. However, this has been prohibitively computationally expensive, meaning that full inverse scattering ultrasound tomography has not been considered clinically viable. Here we show the results of applying a nonlinear inverse scattering algorithm to 3D data in a clinically useful time frame. This method yields Quantitative Transmission (QT) ultrasound images with high spatial and contrast resolution. We reconstruct sound speeds for various 2D and 3D phantoms and verify these values with independent measurements. The data are fully 3D as is the reconstruction algorithm, with no 2D approximations. We show that 2D reconstruction algorithms can introduce artifacts into the QT breast image which are avoided by using a full 3D algorithm and data. We show high resolution gross and microscopic anatomic correlations comparing cadaveric breast QT images with MRI to establish imaging capability and accuracy. Finally, we show reconstructions of data from volunteers, as well as an objective visual grading analysis to confirm clinical imaging capability and accuracy.

Quantitative muscle ultrasound in Duchenne muscular dystrophy: a comparison of techniques.

PubMed

Shklyar, Irina; Geisbush, Tom R; Mijialovic, Aleksandar S; Pasternak, Amy; Darras, Basil T; Wu, Jim S; Rutkove, Seward B; Zaidman, Craig M

2015-02-01

Muscle pathology in Duchenne muscular dystrophy (DMD) can be quantified using ultrasound by measuring either the amplitudes of sound-waves scattered back from the tissue [quantitative backscatter analysis (QBA)] or by measuring these backscattered amplitudes after compression into grayscale levels (GSL) obtained from the images. We measured and compared QBA and GSL from 6 muscles of 25 boys with DMD and 25 healthy subjects, aged 2-14 years, with age and, in DMD, with function (North Star Ambulatory Assessment). Both QBA and GSL were measured reliably (intraclass correlation ≥ 0.87) and were higher in DMD than controls (P < 0.0001). In DMD, average QBA and GSL measured from superficial regions of muscle increased (rho ≥ 0.47, P < 0.05) with both higher age and worse function; in contrast, GSL measured from whole regions of muscle did not. QBA and GSL measured from superficial regions of muscle can similarly quantify muscle pathology in DMD. © 2014 Wiley Periodicals, Inc.

Spinal curvature measurement by tracked ultrasound snapshots.

PubMed

Ungi, Tamas; King, Franklin; Kempston, Michael; Keri, Zsuzsanna; Lasso, Andras; Mousavi, Parvin; Rudan, John; Borschneck, Daniel P; Fichtinger, Gabor

2014-02-01

Monitoring spinal curvature in adolescent kyphoscoliosis requires regular radiographic examinations; however, the applied ionizing radiation increases the risk of cancer. Ultrasound imaging is favored over radiography because it does not emit ionizing radiation. Therefore, we tested an ultrasound system for spinal curvature measurement, with the help of spatial tracking of the ultrasound transducer. Tracked ultrasound was used to localize vertebral transverse processes as landmarks along the spine to measure curvature angles. The method was tested in two scoliotic spine models by localizing the same landmarks using both ultrasound and radiographic imaging and comparing the angles obtained. A close correlation was found between tracked ultrasound and radiographic curvature measurements. Differences between results of the two methods were 1.27 ± 0.84° (average ± SD) in an adult model and 0.96 ± 0.87° in a pediatric model. Our results suggest that tracked ultrasound may become a more tolerable and more accessible alternative to radiographic spine monitoring in adolescent kyphoscoliosis. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

A method to validate quantitative high-frequency power doppler ultrasound with fluorescence in vivo video microscopy.

PubMed

Pinter, Stephen Z; Kim, Dae-Ro; Hague, M Nicole; Chambers, Ann F; MacDonald, Ian C; Lacefield, James C

2014-08-01

Flow quantification with high-frequency (>20 MHz) power Doppler ultrasound can be performed objectively using the wall-filter selection curve (WFSC) method to select the cutoff velocity that yields a best-estimate color pixel density (CPD). An in vivo video microscopy system (IVVM) is combined with high-frequency power Doppler ultrasound to provide a method for validation of CPD measurements based on WFSCs in mouse testicular vessels. The ultrasound and IVVM systems are instrumented so that the mouse remains on the same imaging platform when switching between the two modalities. In vivo video microscopy provides gold-standard measurements of vascular diameter to validate power Doppler CPD estimates. Measurements in four image planes from three mice exhibit wide variation in the optimal cutoff velocity and indicate that a predetermined cutoff velocity setting can introduce significant errors in studies intended to quantify vascularity. Consistent with previously published flow-phantom data, in vivo WFSCs exhibited three characteristic regions and detectable plateaus. Selection of a cutoff velocity at the right end of the plateau yielded a CPD close to the gold-standard vascular volume fraction estimated using IVVM. An investigator can implement the WFSC method to help adapt cutoff velocity to current blood flow conditions and thereby improve the accuracy of power Doppler for quantitative microvascular imaging. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Quantitative ultrasound method for assessing stress-strain properties and the cross-sectional area of Achilles tendon

NASA Astrophysics Data System (ADS)

Du, Yi-Chun; Chen, Yung-Fu; Li, Chien-Ming; Lin, Chia-Hung; Yang, Chia-En; Wu, Jian-Xing; Chen, Tainsong

2013-12-01

The Achilles tendon is one of the most commonly observed tendons injured with a variety of causes, such as trauma, overuse and degeneration, in the human body. Rupture and tendinosis are relatively common for this strong tendon. Stress-strain properties and shape change are important biomechanical properties of the tendon to assess surgical repair or healing progress. Currently, there are rather limited non-invasive methods available for precisely quantifying the in vivo biomechanical properties of the tendons. The aim of this study was to apply quantitative ultrasound (QUS) methods, including ultrasonic attenuation and speed of sound (SOS), to investigate porcine tendons in different stress-strain conditions. In order to find a reliable method to evaluate the change of tendon shape, ultrasound measurement was also utilized for measuring tendon thickness and compared with the change in tendon cross-sectional area under different stress. A total of 15 porcine tendons of hind trotters were examined. The test results show that the attenuation and broadband ultrasound attenuation decreased and the SOS increased by a smaller magnitude as the uniaxial loading of the stress-strain upon tendons increased. Furthermore, the tendon thickness measured with the ultrasound method was significantly correlated with tendon cross-sectional area (Pearson coefficient = 0.86). These results also indicate that attenuation of QUS and ultrasonic thickness measurement are reliable and potential parameters for assessing biomechanical properties of tendons. Further investigations are needed to warrant the application of the proposed method in a clinical setting.

Time-dependent hardening of blood clots quantitatively measured in vivo with shear-wave ultrasound imaging in a rabbit model of venous thrombosis.

PubMed

Mfoumou, Etienne; Tripette, Julien; Blostein, Mark; Cloutier, Guy

2014-02-01

Provide in vivo blood clot hardening evolution with ultrasound using supersonic imaging of shear waves. We conducted a prospective study in flow stasis-induced venous thrombosis within jugular veins of white female New Zealand rabbits. Blood clot elasticity was noninvasively measured in vivo using the Young's modulus (in kilopascals), on a 2-hour and a 2-week periods after thrombus induction. Monitoring was followed by a necropsy and ex vivo mechanical characterization to validate the existence and elasticity of explanted thrombi. Stagnant blood in the region of interest underwent clotting and progressive hardening with thrombus aging. The mean Young's moduli varied from 1.0 ± 0.6 kPa (at 10 min) to 5.3 ± 1.6 kPa (at 2 hours), then to 25.0 ± 6.8 kPa (at 14 days) post-surgery. Mean ex vivo moduli of 6.2 ± 0.7 kPa at 2 hours and 29.0 ± 2.4 kPa at 2 weeks agreed with in vivo measures. Supersonic imaging of shear waves provides consistent quantitative non-invasive elasticity measurements not available with standard compression ultrasound imaging for diagnosing and following venous thromboembolism. This information translatable to humans could aid in determining whether continued anticoagulant treatment is necessary, especially in the setting of unprovoked venous thromboembolism. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ultrasound Assessment of Human Meniscus.

PubMed

Viren, Tuomas; Honkanen, Juuso T; Danso, Elvis K; Rieppo, Lassi; Korhonen, Rami K; Töyräs, Juha

2017-09-01

The aim of the present study was to evaluate the applicability of ultrasound imaging to quantitative assessment of human meniscus in vitro. Meniscus samples (n = 26) were harvested from 13 knee joints of non-arthritic human cadavers. Subsequently, three locations (anterior, center and posterior) from each meniscus were imaged with two ultrasound transducers (frequencies 9 and 40 MHz), and quantitative ultrasound parameters were determined. Furthermore, partial-least-squares regression analysis was applied for ultrasound signal to determine the relations between ultrasound scattering and meniscus integrity. Significant correlations between measured and predicted meniscus compositions and mechanical properties were obtained (R 2  = 0.38-0.69, p < 0.05). The relationship between conventional ultrasound parameters and integrity of the meniscus was weaker. To conclude, ultrasound imaging exhibited a potential for evaluation of meniscus integrity. Higher ultrasound frequency combined with multivariate analysis of ultrasound backscattering was found to be the most sensitive for evaluation of meniscus integrity. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Ultrasound introscopic image quantitative characteristics for medical diagnosis

NASA Astrophysics Data System (ADS)

Novoselets, Mikhail K.; Sarkisov, Sergey S.; Gridko, Alexander N.; Tcheban, Anatoliy K.

1993-09-01

The results on computer aided extraction of quantitative characteristics (QC) of ultrasound introscopic images for medical diagnosis are presented. Thyroid gland (TG) images of Chernobil Accident sufferers are considered. It is shown that TG diseases can be associated with some values of selected QCs of random echo distribution in the image. The possibility of these QCs usage for TG diseases recognition in accordance with calculated values is analyzed. The role of speckle noise elimination in the solution of the problem on TG diagnosis is considered too.

Epidemiological survey of quantitative ultrasound in risk assessment of falls in middle-aged and elderly people.

PubMed

Ou, Ling-Chun; Sun, Zih-Jie; Chang, Yin-Fan; Chang, Chin-Sung; Chao, Ting-Hsing; Kuo, Po-Hsiu; Lin, Ruey-Mo; Wu, Chih-Hsing

2013-01-01

The risk assessment of falls is important, but still unsatisfactory and time-consuming. Our objective was to assess quantitative ultrasound (QUS) in the risk assessment of falls. Our study was designed as epidemiological cross-sectional study occurring from March 2009 to February 2010 by community survey at a medical center. The participants were collected from systemic sample of 1,200 community-dwelling people (Male/Female = 524/676) 40 years old and over in Yunlin County, Mid-Taiwan. Structural questionnaires including socioeconomic status, living status, smoking and drinking habits, exercise and medical history were completed. Quantitative ultrasound (QUS) at the non-dominant distal radial area (QUS-R) and the left calcaneal area (QUS-C) were measured. The overall prevalence of falls was 19.8%. In men, the independently associated factors for falls were age (OR: 1.04; 95%CI: 1.01~1.06), fracture history (OR: 1.89; 95%CI: 1.12~3.19), osteoarthritis history (OR: 3.66; 95%CI: 1.15~11.64) and speed of sound (OR: 0.99; 95%CI: 0.99~1.00; p<0.05) by QUS-R. In women, the independently associated factors for falls were current drinking (OR: 3.54; 95%CI: 1.35∼9.31) and broadband ultrasound attenuation (OR: 0.98; 95%CI: 0.97~0.99; p<0.01) by QUS-C. The cutoffs at -2.5< T-score<-1 derived using QUS-R (OR: 2.85; 95%CI: 1.64~4.96; p<0.01) in men or T-score ≦-2.5 derived using QUS-C (OR: 2.72; 95%CI: 1.42~5.21; p<0.01) in women showed an independent association with falls. The lowest T-score derived using either QUS-R or QUS-C was also revealed as an independent factor for falls in both men (OR: 2.13; 95%CI: 1.03~4.43; p<0.05) and women (OR: 2.36; 95%CI: 1.13~4.91; p<0.05). Quantitative ultrasounds, measured either at the radial or calcaneal area, are convenient tools by which to assess the risk of falls in middle-aged and elderly people.

Quantitative ultrasound molecular imaging by modeling the binding kinetics of targeted contrast agent

NASA Astrophysics Data System (ADS)

Turco, Simona; Tardy, Isabelle; Frinking, Peter; Wijkstra, Hessel; Mischi, Massimo

2017-03-01

Ultrasound molecular imaging (USMI) is an emerging technique to monitor diseases at the molecular level by the use of novel targeted ultrasound contrast agents (tUCA). These consist of microbubbles functionalized with targeting ligands with high-affinity for molecular markers of specific disease processes, such as cancer-related angiogenesis. Among the molecular markers of angiogenesis, the vascular endothelial growth factor receptor 2 (VEGFR2) is recognized to play a major role. In response, the clinical-grade tUCA BR55 was recently developed, consisting of VEGFR2-targeting microbubbles which can flow through the entire circulation and accumulate where VEGFR2 is over-expressed, thus causing selective enhancement in areas of active angiogenesis. Discrimination between bound and free microbubbles is crucial to assess cancer angiogenesis. Currently, this is done non-quantitatively by looking at the late enhancement, about 10 min after injection, or by calculation of the differential targeted enhancement, requiring the application of a high-pressure ultrasound (US) burst to destroy all the microbubbles in the acoustic field and isolate the signal coming only from bound microbubbles. In this work, we propose a novel method based on mathematical modeling of the binding kinetics during the tUCA first pass, thus reducing the acquisition time and with no need for a destructive US burst. Fitting time-intensity curves measured with USMI by the proposed model enables the assessment of cancer angiogenesis at both the vascular and molecular levels. This is achieved by estimation of quantitative parameters related to the microvascular architecture and microbubble binding. The proposed method was tested in 11 prostate-tumor bearing rats by performing USMI after injection of BR55, and showed good agreement with current USMI methods. The novel information provided by the proposed method, possibly combined with the current non-quantitative methods, may bring deeper insight into

Prospective evaluation of risk of vertebral fractures using quantitative ultrasound measurements and bone mineral density in a population-based sample of postmenopausal women: results of the Basel Osteoporosis Study.

PubMed

Hollaender, R; Hartl, F; Krieg, M-A; Tyndall, A; Geuckel, C; Buitrago-Tellez, C; Manghani, M; Kraenzlin, M; Theiler, R; Hans, D

2009-03-01

Prospective studies have shown that quantitative ultrasound (QUS) techniques predict the risk of fracture of the proximal femur with similar standardised risk ratios to dual-energy x-ray absorptiometry (DXA). Few studies have investigated these devices for the prediction of vertebral fractures. The Basel Osteoporosis Study (BOS) is a population-based prospective study to assess the performance of QUS devices and DXA in predicting incident vertebral fractures. 432 women aged 60-80 years were followed-up for 3 years. Incident vertebral fractures were assessed radiologically. Bone measurements using DXA (spine and hip) and QUS measurements (calcaneus and proximal phalanges) were performed. Measurements were assessed for their value in predicting incident vertebral fractures using logistic regression. QUS measurements at the calcaneus and DXA measurements discriminated between women with and without incident vertebral fracture, (20% height reduction). The relative risks (RRs) for vertebral fracture, adjusted for age, were 2.3 for the Stiffness Index (SI) and 2.8 for the Quantitative Ultrasound Index (QUI) at the calcaneus and 2.0 for bone mineral density at the lumbar spine. The predictive value (AUC (95% CI)) of QUS measurements at the calcaneus remained highly significant (0.70 for SI, 0.72 for the QUI, and 0.67 for DXA at the lumbar spine) even after adjustment for other confounding variables. QUS of the calcaneus and bone mineral density measurements were shown to be significant predictors of incident vertebral fracture. The RRs for QUS measurements at the calcaneus are of similar magnitude as for DXA measurements.

Does quantitative ultrasound imaging enhance precision and discrimination?

PubMed

Frost, M L; Blake, G M; Fogelman, I

2000-01-01

The aim of this study was to compare quantitative ultrasound (QUS) measurements obtained using a new calcaneal QUS imaging device with a conventional non-imaging device using fixed transducers. The study group consisted of 340 healthy women with no risk factors associated with osteoporosis (176 premenopausal and 164 postmenopausal) and 83 women with one or more vertebral fractures. All women had QUS measurements performed on the Osteometer DTU-one (imaging) and Walker-Sonix UBA575+ (non-imaging) devices and bone mineral density (BMD) measurements performed at the spine and hip. A subgroup of 81 women had additional dual-energy X-ray absorptiometry (DXA) scans at the calcaneus. Short-term standardized precision (SP = SD/young adult SD) based on duplicate measurements was significantly better on the DTU for broadband ultrasound attenuation (BUA) (SP: DTU 0.15 vs UBA 0.21,p = 0.01) and speed of sound (SOS) (SP: DTU 0.14 vs UBA 0.18, p = 0.01). However, long-term SP of the DTU was comparable to or significantly poorer than the SP of the UBA device. The BUA and SOS measurements obtained on the DTU and UBA were significantly correlated (r = 0.76 and 0.89 for BUA and SOS measurements respectively). The correlations between QUS and BMD measurements were all significant, ranging from 0.53 to 0.72. No significant improvements in the correlation with axial or peripheral BMD were observed using the imaging device. All the QUS measurement parameters showed a significant negative relationship between age and years since menopause in the postmenopausal group. Annual losses were lower for the DTU for BUA (DTU 0.22 dB/MHz per year vs UBA 0.44 dB/MHz per year) but comparable for SOS (DTU 0.29 m/s per-year vs UBA 0.22 m/s per year). However, when these figures were standardized to take into account the clinical range, the annual losses were similar on the DTU and UBA. Age-adjusted odds ratios for each SD decline were similar on the DTU for BUA (DTU 3.2 vs UBA 3.3) and SOS (DTU 3.4 vs

Urinary Mineral Concentrations in European Pre-Adolescent Children and Their Association with Calcaneal Bone Quantitative Ultrasound Measurements †

PubMed Central

Van den Bussche, Karen; Herrmann, Diana; De Henauw, Stefaan; Kourides, Yiannis A.; Lauria, Fabio; Marild, Staffan; Molnár, Dénes; Moreno, Luis A.; Veidebaum, Toomas; Ahrens, Wolfgang; Sioen, Isabelle

2016-01-01

This study investigates differences and associations between urinary mineral concentrations and calcaneal bone measures assessed by quantitative ultrasonography (QUS) in 4322 children (3.1–11.9 years, 50.6% boys) from seven European countries. Urinary mineral concentrations and calcaneal QUS parameters differed significantly across countries. Clustering revealed a lower stiffness index (SI) in children with low and medium urinary mineral concentrations, and a higher SI in children with high urinary mineral concentrations. Urinary sodium (uNa) was positively correlated with urinary calcium (uCa), and was positively associated with broadband ultrasound attenuation and SI after adjustment for age, sex and fat-free mass. Urinary potassium (uK) was negatively correlated with uCa but positively associated with speed of sound after adjustment. No association was found between uCa and QUS parameters after adjustment, but when additionally adjusting for uNa, uCa was negatively associated with SI. Our findings suggest that urinary mineral concentrations are associated with calcaneal QUS parameters and may therefore implicate bone properties. These findings should be confirmed in longitudinal studies that include the food intake and repeated measurement of urinary mineral concentrations to better estimate usual intake and minimize bias. PMID:27164120

Comparison of sound speed measurements on two different ultrasound tomography devices

NASA Astrophysics Data System (ADS)

Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Sherman, Mark; Gierach, Gretchen; Malyarenko, Antonina

2014-03-01

Ultrasound tomography (UST) employs sound waves to produce three-dimensional images of breast tissue and precisely measures the attenuation of sound speed secondary to breast tissue composition. High breast density is a strong breast cancer risk factor and sound speed is directly proportional to breast density. UST provides a quantitative measure of breast density based on three-dimensional imaging without compression, thereby overcoming the shortcomings of many other imaging modalities. The quantitative nature of the UST breast density measures are tied to an external standard, so sound speed measurement in breast tissue should be independent of specific hardware. The work presented here compares breast sound speed measurement obtained with two different UST devices. The Computerized Ultrasound Risk Evaluation (CURE) system located at the Karmanos Cancer Institute in Detroit, Michigan was recently replaced with the SoftVue ultrasound tomographic device. Ongoing clinical trials have used images generated from both sets of hardware, so maintaining consistency in sound speed measurements is important. During an overlap period when both systems were in the same exam room, a total of 12 patients had one or both of their breasts imaged on both systems on the same day. There were 22 sound speed scans analyzed from each system and the average breast sound speeds were compared. Images were either reconstructed using saved raw data (for both CURE and SoftVue) or were created during the image acquisition (saved in DICOM format for SoftVue scans only). The sound speed measurements from each system were strongly and positively correlated with each other. The average difference in sound speed between the two sets of data was on the order of 1-2 m/s and this result was not statistically significant. The only sets of images that showed a statistical difference were the DICOM images created during the SoftVue scan compared to the SoftVue images reconstructed from the raw data

Intra- and interobserver reliability of quantitative ultrasound measurement of the plantar fascia.

PubMed

Rathleff, Michael Skovdal; Moelgaard, Carsten; Lykkegaard Olesen, Jens

2011-01-01

To determine intra- and interobserver reliability and measurement precision of sonographic assessment of plantar fascia thickness when using one, the mean of two, or the mean of three measurements. Two experienced observers scanned 20 healthy subjects twice with 60 minutes between test and retest. A GE LOGIQe ultrasound scanner was used in the study. The built-in software in the scanner was used to measure the thickness of the plantar fascia (PF). Reliability was calculated using intraclass correlation coefficient (ICC) and limits of agreement (LOA). Intraobserver reliability (ICC) using one measurement was 0.50 for one observer and 0.52 for the other, and using the mean of three measurements intraobserver reliability increased up to 0.77 and 0.67, respectively. Interobserver reliability (ICC) when using one measurement was 0.62 and increased to 0.82 when using the average of three measurements. LOA showed that when using the average of three measurements, LOA decreased to 0.6 mm, corresponding to 17.5% of the mean thickness of the PF. The results showed that reliability increases when using the mean of three measurements compared with one. Limits of agreement based on intratester reliability shows that changes in thickness that are larger than 0.6 mm can be considered actual changes in thickness and not a result of measurement error. Copyright © 2011 Wiley Periodicals, Inc.

Measurement of corneal tangent modulus using ultrasound indentation.

PubMed

Wang, Li-Ke; Huang, Yan-Ping; Tian, Lei; Kee, Chea-Su; Zheng, Yong-Ping

2016-09-01

Biomechanical properties are potential information for the diagnosis of corneal pathologies. An ultrasound indentation probe consisting of a load cell and a miniature ultrasound transducer as indenter was developed to detect the force-indentation relationship of the cornea. The key idea was to utilize the ultrasound transducer to compress the cornea and to ultrasonically measure the corneal deformation with the eyeball overall displacement compensated. Twelve corneal silicone phantoms were fabricated with different stiffness for the validation of measurement with reference to an extension test. In addition, fifteen fresh porcine eyes were measured by the developed system in vitro. The tangent moduli of the corneal phantoms calculated using the ultrasound indentation data agreed well with the results from the tensile test of the corresponding phantom strips (R(2)=0.96). The mean tangent moduli of the porcine corneas measured by the proposed method were 0.089±0.026MPa at intraocular pressure (IOP) of 15mmHg and 0.220±0.053MPa at IOP of 30mmHg, respectively. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) of tangent modulus were 14.4% and 0.765 at 15mmHg, and 8.6% and 0.870 at 30mmHg, respectively. The preliminary study showed that ultrasound indentation could be applied to the measurement of corneal tangent modulus with good repeatability and improved measurement accuracy compared to conventional surface displacement-based measurement method. The ultrasound indentation can be a potential tool for the corneal biomechanical properties measurement in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

2D/ 3D Quantitative Ultrasound of the Breast

NASA Astrophysics Data System (ADS)

Nasief, Haidy Gerges

Breast cancer is the second leading cause of cancer death of women in the United States, so breast cancer screening for early detection is common. The purpose of this dissertation is to optimize quantitative ultrasound (QUS) methods to improve the specificity and objectivity of breast ultrasound. To pursue this goal, the dissertation is divided into two parts: 1) to optimize 2D QUS, and 2) to introduce and validate 3D QUS. Previous studies had validated these methods in phantoms. Applying our QUS analysis on subcutaneous breast fat demonstrated that QUS parameter estimates for subcutaneous fat were consistent among different human subjects. This validated our in vivo data acquisition methods and supported the use of breast fat as a clinical reference tissue for ultrasound BI-RADSRTM assessments. Although current QUS methods perform well for straightforward cases when assumptions of stationarity and diffuse scattering are well-founded, these conditions often are not present due to the complicated nature of in vivo breast tissue. Key improvements in QUS algorithms to address these challenges were: 1) applying a "modified least squares method (MLSM)" to account for the heterogeneous tissue path between the transducer and the region of interest, ROI; 2) detecting anisotropy in acoustic parameters; and 3) detecting and removing the echo sources that depart from diffuse and stationary scattering conditions. The results showed that a Bayesian classifier combining three QUS parameters in a biased pool of high-quality breast ultrasound data successfully differentiated all fibroadenomas from all carcinomas. Given promising initial results in 2D, extension to 3D acquisitions in QUS provided a unique capability to test QUS for the entire breast volume. QUS parameter estimates using 3D data were consistent with those found in 2D for phantoms and in vivo data. Extensions of QUS technology from 2D to 3D can improve the specificity of breast ultrasound, and thus, could lead to

VALIDATION OF ULTRASOUND AS A NONINVASIVE TOOL TO MEASURE SUBCUTANEOUS FAT DEPTH IN LEATHERBACK SEA TURTLES (DERMOCHELYS CORIACEA).

PubMed

Harris, Heather S; Benson, Scott R; James, Michael C; Martin, Kelly J; Stacy, Brian A; Daoust, Pierre-Yves; Rist, Paul M; Work, Thierry M; Balazs, George H; Seminoff, Jeffrey A

2016-03-01

Leatherback turtles (Dermochelys coriacea) undergo substantial cyclical changes in body condition between foraging and nesting. Ultrasonography has been used to measure subcutaneous fat as an indicator of body condition in many species but has not been applied in sea turtles. To validate this technique in leatherback turtles, ultrasound images were obtained from 36 live-captured and dead-stranded immature and adult turtles from foraging and nesting areas in the Pacific and Atlantic oceans. Ultrasound measurements were compared with direct measurements from surgical biopsy or necropsy. Tissue architecture was confirmed histologically in a subset of turtles. The dorsal shoulder region provided the best site for differentiation of tissues. Maximum fat depth values with the front flipper in a neutral (45-90°) position demonstrated good correlation with direct measurements. Ultrasound-derived fat measurements may be used in the future for quantitative assessment of body condition as an index of health in this critically endangered species.

Validation of ultrasound as a noninvasive tool to measure subcutaneous fat depth in leatherback sea turtles (Dermochelys coriacea)

USGS Publications Warehouse

Harris, Heather S.; Benson, Scott R.; James, Michael C.; Martin, Kelly J.; Stacy, Brian A.; Daoust, Pierre-Yves; Rist, Paul M.; Work, Thierry M.; Balazs, George H.; Seminoff, Jeffrey A.

2016-01-01

Leatherback turtles (Dermochelys coriacea) undergo substantial cyclical changes in body condition between foraging and nesting. Ultrasonography has been used to measure subcutaneous fat as an indicator of body condition in many species but has not been applied in sea turtles. To validate this technique in leatherback turtles, ultrasound images were obtained from 36 live-captured and dead-stranded immature and adult turtles from foraging and nesting areas in the Pacific and Atlantic oceans. Ultrasound measurements were compared with direct measurements from surgical biopsy or necropsy. Tissue architecture was confirmed histologically in a subset of turtles. The dorsal shoulder region provided the best site for differentiation of tissues. Maximum fat depth values with the front flipper in a neutral (45–90°) position demonstrated good correlation with direct measurements. Ultrasound-derived fat measurements may be used in the future for quantitative assessment of body condition as an index of health in this critically endangered species.

Focused ultrasound thermal therapy system with ultrasound image guidance and temperature measurement feedback.

PubMed

Lin, Kao-Han; Young, Sun-Yi; Hsu, Ming-Chuan; Chan, Hsu; Chen, Yung-Yaw; Lin, Win-Li

2008-01-01

In this study, we developed a focused ultrasound (FUS) thermal therapy system with ultrasound image guidance and thermocouple temperature measurement feedback. Hydraulic position devices and computer-controlled servo motors were used to move the FUS transducer to the desired location with the measurement of actual movement by linear scale. The entire system integrated automatic position devices, FUS transducer, power amplifier, ultrasound image system, and thermocouple temperature measurement into a graphical user interface. For the treatment procedure, a thermocouple was implanted into a targeted treatment region in a tissue-mimicking phantom under ultrasound image guidance, and then the acoustic interference pattern formed by image ultrasound beam and low-power FUS beam was employed as image guidance to move the FUS transducer to have its focal zone coincident with the thermocouple tip. The thermocouple temperature rise was used to determine the sonication duration for a suitable thermal lesion as a high power was turned on and ultrasound image was used to capture the thermal lesion formation. For a multiple lesion formation, the FUS transducer was moved under the acoustic interference guidance to a new location and then it sonicated with the same power level and duration. This system was evaluated and the results showed that it could perform two-dimensional motion control to do a two-dimensional thermal therapy with a small localization error 0.5 mm. Through the user interface, the FUS transducer could be moved to heat the target region with the guidance of ultrasound image and acoustic interference pattern. The preliminary phantom experimental results demonstrated that the system could achieve the desired treatment plan satisfactorily.

Relationship between bone turnover markers and the heel stiffness index measured by quantitative ultrasound in middle-aged and elderly Japanese men

PubMed Central

Nishimura, Takayuki; Arima, Kazuhiko; Abe, Yasuyo; Kanagae, Mitsuo; Mizukami, Satoshi; Okabe, Takuhiro; Tomita, Yoshihito; Goto, Hisashi; Horiguchi, Itsuko; Aoyagi, Kiyoshi

2018-01-01

Abstract The aim of the present study was to investigate the age-related patterns and the relationships between serum levels of tartrate-resistant acid phosphatase-5b (TRACP-5b) or bone-specific alkaline phosphatase (BAP), and the heel stiffness index measured by quantitative ultrasound (QUS) in 429 Japanese men, with special emphasis on 2 age groups (40–59 years and 60 years or over). The heel stiffness index (bone mass) was measured by QUS. Serum samples were collected, and TRACP-5b and BAP levels were measured. The stiffness index was significantly decreased with age. Log (TRACP-5b) was significantly increased with age, but Log (BAP) was stable. Generalized linear models showed that higher levels of Log (TRACP-5b) and Log (BAP) were correlated with a lower stiffness index after adjusting for covariates in men aged 60 years or over, but not in men aged 40 to 59 years. In conclusion, higher rates of bone turnover markers were associated with a lower stiffness index only in elderly men. These results may indicate a different mechanism of low bone mass among different age groups of men. PMID:29465590

Multimedia systems in ultrasound image boundary detection and measurements

NASA Astrophysics Data System (ADS)

Pathak, Sayan D.; Chalana, Vikram; Kim, Yongmin

1997-05-01

Ultrasound as a medical imaging modality offers the clinician a real-time of the anatomy of the internal organs/tissues, their movement, and flow noninvasively. One of the applications of ultrasound is to monitor fetal growth by measuring biparietal diameter (BPD) and head circumference (HC). We have been working on automatic detection of fetal head boundaries in ultrasound images. These detected boundaries are used to measure BPD and HC. The boundary detection algorithm is based on active contour models and takes 32 seconds on an external high-end workstation, SUN SparcStation 20/71. Our goal has been to make this tool available within an ultrasound machine and at the same time significantly improve its performance utilizing multimedia technology. With the advent of high- performance programmable digital signal processors (DSP), the software solution within an ultrasound machine instead of the traditional hardwired approach or requiring an external computer is now possible. We have integrated our boundary detection algorithm into a programmable ultrasound image processor (PUIP) that fits into a commercial ultrasound machine. The PUIP provides both the high computing power and flexibility needed to support computationally-intensive image processing algorithms within an ultrasound machine. According to our data analysis, BPD/HC measurements made on PUIP lie within the interobserver variability. Hence, the errors in the automated BPD/HC measurements using the algorithm are on the same order as the average interobserver differences. On PUIP, it takes 360 ms to measure the values of BPD/HC on one head image. When processing multiple head images in sequence, it takes 185 ms per image, thus enabling 5.4 BPD/HC measurements per second. Reduction in the overall execution time from 32 seconds to a fraction of a second and making this multimedia system available within an ultrasound machine will help this image processing algorithm and other computer-intensive imaging

Quantitative volumetric imaging of normal, neoplastic and hyperplastic mouse prostate using ultrasound.

PubMed

Singh, Shalini; Pan, Chunliu; Wood, Ronald; Yeh, Chiuan-Ren; Yeh, Shuyuan; Sha, Kai; Krolewski, John J; Nastiuk, Kent L

2015-09-21

Genetically engineered mouse models are essential to the investigation of the molecular mechanisms underlying human prostate pathology and the effects of therapy on the diseased prostate. Serial in vivo volumetric imaging expands the scope and accuracy of experimental investigations of models of normal prostate physiology, benign prostatic hyperplasia and prostate cancer, which are otherwise limited by the anatomy of the mouse prostate. Moreover, accurate imaging of hyperplastic and tumorigenic prostates is now recognized as essential to rigorous pre-clinical trials of new therapies. Bioluminescent imaging has been widely used to determine prostate tumor size, but is semi-quantitative at best. Magnetic resonance imaging can determine prostate volume very accurately, but is expensive and has low throughput. We therefore sought to develop and implement a high throughput, low cost, and accurate serial imaging protocol for the mouse prostate. We developed a high frequency ultrasound imaging technique employing 3D reconstruction that allows rapid and precise assessment of mouse prostate volume. Wild-type mouse prostates were examined (n = 4) for reproducible baseline imaging, and treatment effects on volume were compared, and blinded data analyzed for intra- and inter-operator assessments of reproducibility by correlation and for Bland-Altman analysis. Examples of benign prostatic hyperplasia mouse model prostate (n = 2) and mouse prostate implantation of orthotopic human prostate cancer tumor and its growth (n =  ) are also demonstrated. Serial measurement volume of the mouse prostate revealed that high frequency ultrasound was very precise. Following endocrine manipulation, regression and regrowth of the prostate could be monitored with very low intra- and interobserver variability. This technique was also valuable to monitor the development of prostate growth in a model of benign prostatic hyperplasia. Additionally, we demonstrate accurate ultrasound image

Acoustic pressure measurement of pulsed ultrasound using acousto-optic diffraction

NASA Astrophysics Data System (ADS)

Jia, Lecheng; Chen, Shili; Xue, Bin; Wu, Hanzhong; Zhang, Kai; Yang, Xiaoxia; Zeng, Zhoumo

2018-01-01

Compared with continuous ultrasound wave, pulsed ultrasound has been widely used in ultrasound imaging. The aim of this work is to show the applicability of acousto-optic diffraction on pulsed ultrasound transducer. In this paper, acoustic pressure of two ultrasound transducers is measured based on Raman-Nath diffraction. The frequencies of transducers are 5MHz and 10MHz. The pulse-echo method and simulation data are used to evaluate the results. The results show that the proposed method is capable to measure the absolute sound pressure. We get a sectional view of acoustic pressure using a displacement platform as an auxiliary. Compared with the traditional sound pressure measurement methods, the proposed method is non-invasive with high sensitivity and spatial resolution.

Breast tumour visualization using 3D quantitative ultrasound methods

NASA Astrophysics Data System (ADS)

Gangeh, Mehrdad J.; Raheem, Abdul; Tadayyon, Hadi; Liu, Simon; Hadizad, Farnoosh; Czarnota, Gregory J.

2016-04-01

Breast cancer is one of the most common cancer types accounting for 29% of all cancer cases. Early detection and treatment has a crucial impact on improving the survival of affected patients. Ultrasound (US) is non-ionizing, portable, inexpensive, and real-time imaging modality for screening and quantifying breast cancer. Due to these attractive attributes, the last decade has witnessed many studies on using quantitative ultrasound (QUS) methods in tissue characterization. However, these studies have mainly been limited to 2-D QUS methods using hand-held US (HHUS) scanners. With the availability of automated breast ultrasound (ABUS) technology, this study is the first to develop 3-D QUS methods for the ABUS visualization of breast tumours. Using an ABUS system, unlike the manual 2-D HHUS device, the whole patient's breast was scanned in an automated manner. The acquired frames were subsequently examined and a region of interest (ROI) was selected in each frame where tumour was identified. Standard 2-D QUS methods were used to compute spectral and backscatter coefficient (BSC) parametric maps on the selected ROIs. Next, the computed 2-D parameters were mapped to a Cartesian 3-D space, interpolated, and rendered to provide a transparent color-coded visualization of the entire breast tumour. Such 3-D visualization can potentially be used for further analysis of the breast tumours in terms of their size and extension. Moreover, the 3-D volumetric scans can be used for tissue characterization and the categorization of breast tumours as benign or malignant by quantifying the computed parametric maps over the whole tumour volume.

Dichotomous versus semi-quantitative scoring of ultrasound joint inflammation in rheumatoid arthritis using novel individualized joint selection methods.

PubMed

Tan, York Kiat; Allen, John C; Lye, Weng Kit; Conaghan, Philip G; Chew, Li-Ching; Thumboo, Julian

2017-05-01

The aim of the study is to compare the responsiveness of two joint inflammation scoring systems (dichotomous scoring (DS) versus semi-quantitative scoring (SQS)) using novel individualized ultrasound joint selection methods and existing ultrasound joint selection methods. Responsiveness measured by the standardized response means (SRMs) using the DS and the SQS system (for both the novel and existing ultrasound joint selection methods) was derived using the baseline and the 3-month total inflammatory scores from 20 rheumatoid arthritis patients. The relative SRM gain ratios (SRM-Gains) for both scoring system (DS and SQS) comparing the novel to the existing methods were computed. Both scoring systems (DS and SQS) demonstrated substantial SRM-Gains (ranged from 3.31 to 5.67 for the DS system and ranged from 1.82 to 3.26 for the SQS system). The SRMs using the novel methods ranged from 0.94 to 1.36 for the DS system and ranged from 0.89 to 1.11 for the SQS system. The SRMs using the existing methods ranged from 0.24 to 0.32 for the DS system and ranged from 0.34 to 0.49 for the SQS system. The DS system appears to achieve high responsiveness comparable to SQS for the novel individualized ultrasound joint selection methods.

Clinical workflow for spinal curvature measurement with portable ultrasound

NASA Astrophysics Data System (ADS)

Tabanfar, Reza; Yan, Christina; Kempston, Michael; Borschneck, Daniel; Ungi, Tamas; Fichtinger, Gabor

2016-03-01

PURPOSE: Spinal curvature monitoring is essential in making treatment decisions in scoliosis. Monitoring entails radiographic examinations, however repeated ionizing radiation exposure has been shown to increase cancer risk. Ultrasound does not emit ionizing radiation and is safer for spinal curvature monitoring. We investigated a clinical sonography protocol and challenges associated with position-tracked ultrasound in spinal curvature measurement in scoliosis. METHODS: Transverse processes were landmarked along each vertebra using tracked ultrasound snapshots. The transverse process angle was used to determine the orientation of each vertebra. We tested our methodology on five patients in a local pediatric scoliosis clinic, comparing ultrasound to radiographic curvature measurements. RESULTS: Despite strong correlation between radiographic and ultrasound curvature angles in phantom studies, we encountered new challenges in the clinical setting. Our main challenge was differentiating transverse processes from ribs and other structures during landmarking. We observed up to 13° angle variability for a single vertebra and a 9.85° +/- 10.81° difference between ultrasound and radiographic Cobb angles for thoracic curvatures. Additionally, we were unable to visualize anatomical landmarks in the lumbar region where soft tissue depth was 25-35mm. In volunteers with large Cobb angles (greater than 40° thoracic and 60° lumbar), we observed spinal protrusions resulting in incomplete probe-skin contact and partial ultrasound images not suitable for landmarking. CONCLUSION: Spinal curvature measurement using tracked ultrasound is viable on phantom spine models. In the clinic, new challenges were encountered which must be resolved before a universal sonography protocol can be developed.

Spectrophotometer and ultrasound evaluation of late toxicity following breast-cancer radiotherapy

PubMed Central

Yoshida, E. J.; Chen, H.; Torres, M. A.; Curran, W. J.; Liu, T.

2011-01-01

Purpose: Radiation-induced normal-tissue toxicities are common, complex, and distressing side effects that affect 90% of patients receiving breast-cancer radiotherapy and 40% of patients post radiotherapy. In this study, the authors investigated the use of spectrophotometry and ultrasound to quantitatively measure radiation-induced skin discoloration and subcutaneous-tissue fibrosis. The study’s purpose is to determine whether skin discoloration correlates with the development of fibrosis in breast-cancer radiotherapy.Methods : Eighteen breast-cancer patients were enrolled in our initial study. All patients were previously treated with a standard course of radiation, and the median follow-up time was 22 months. The treated and untreated breasts were scanned with a spectrophotometer and an ultrasound. Two spectrophotometer parameters—melanin and erythema indices—were used to quantitatively assess skin discoloration. Two ultrasound parameters—skin thickness and Pearson coefficient of the hypodermis—were used to quantitatively assess severity of fibrosis. These measurements were correlated with clinical assessments (RTOG late morbidity scores).Results: Significant measurement differences between the treated and contralateral breasts were observed among all patients: 27.3% mean increase in skin thickness (p < 0.001), 34.1% mean decrease in Pearson coefficient (p < 0.001), 27.3% mean increase in melanin (p < 0.001), and 22.6% mean increase in erythema (p < 0.001). All parameters except skin thickness correlated with RTOG scores. A moderate correlation exists between melanin and erythema; however, spectrophotometer parameters do not correlate with ultrasound parameters.Conclusions: Spectrophotometry and quantitative ultrasound are objective tools that assess radiation-induced tissue injury. Spectrophotometer parameters did not correlate with those of quantitative ultrasound suggesting that skin discoloration cannot be used as a marker for

Spectrophotometer and ultrasound evaluation of late toxicity following breast-cancer radiotherapy.

PubMed

Yoshida, E J; Chen, H; Torres, M A; Curran, W J; Liu, T

2011-10-01

Radiation-induced normal-tissue toxicities are common, complex, and distressing side effects that affect 90% of patients receiving breast-cancer radiotherapy and 40% of patients post radiotherapy. In this study, the authors investigated the use of spectrophotometry and ultrasound to quantitatively measure radiation-induced skin discoloration and subcutaneous-tissue fibrosis. The study's purpose is to determine whether skin discoloration correlates with the development of fibrosis in breast-cancer radiotherapy. Eighteen breast-cancer patients were enrolled in our initial study. All patients were previously treated with a standard course of radiation, and the median follow-up time was 22 months. The treated and untreated breasts were scanned with a spectrophotometer and an ultrasound. Two spectrophotometer parameters-melanin and erythema indices-were used to quantitatively assess skin discoloration. Two ultrasound parameters-skin thickness and Pearson coefficient of the hypodermis-were used to quantitatively assess severity of fibrosis. These measurements were correlated with clinical assessments (RTOG late morbidity scores). Significant measurement differences between the treated and contralateral breasts were observed among all patients: 27.3% mean increase in skin thickness (p < 0.001), 34.1% mean decrease in Pearson coefficient (p < 0.001), 27.3% mean increase in melanin (p < 0.001), and 22.6% mean increase in erythema (p < 0.001). All parameters except skin thickness correlated with RTOG scores. A moderate correlation exists between melanin and erythema; however, spectrophotometer parameters do not correlate with ultrasound parameters. Spectrophotometry and quantitative ultrasound are objective tools that assess radiation-induced tissue injury. Spectrophotometer parameters did not correlate with those of quantitative ultrasound suggesting that skin discoloration cannot be used as a marker for subcutaneous fibrosis. These tools may prove useful

Comparison of portable and conventional ultrasound imaging in spinal curvature measurement

NASA Astrophysics Data System (ADS)

Yan, Christina; Tabanfar, Reza; Kempston, Michael; Borschneck, Daniel; Ungi, Tamas; Fichtinger, Gabor

2016-03-01

PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks, but bones have reduced visibility in ultrasound imaging and high quality ultrasound machines are often expensive and not portable. In this work, we investigate the image quality and measurement accuracy of a low cost and portable ultrasound machine in comparison to a standard ultrasound machine in scoliosis monitoring. METHODS: Two different kinds of ultrasound machines were tested on three human subjects, using the same position tracker and software. Spinal curves were measured in the same reference coordinate system using both ultrasound machines. Lines were defined by connecting two symmetric landmarks identified on the left and right transverse process of the same vertebrae, and spinal curvature was defined as the transverse process angle between two such lines, projected on the coronal plane. RESULTS: Three healthy volunteers were scanned by both ultrasound configurations. Three experienced observers localized transverse processes as skeletal landmarks and obtained transverse process angles in images obtained from both ultrasounds. The mean difference per transverse process angle measured was 3.00 +/-2.1°. 94% of transverse processes visualized in the Sonix Touch were also visible in the Telemed. Inter-observer error in the Telemed was 4.5° and 4.3° in the Sonix Touch. CONCLUSION: Price, convenience and accessibility suggest the Telemed to be a viable alternative in scoliosis monitoring, however further improvements in measurement protocol and image noise reduction must be completed before implementing the Telemed in the clinical setting.

An Examination of Ultrasound Measured Tissue Perfusion on Breast Cancer

DTIC Science & Technology

1998-12-01

is similar to those of the study by Ivey et al. [9] in which high intensity fields were used to produce cavitation bubbles for ultrasound contrast...ft * * AD AWARD NUMBER DAMD17-94-J-4144 TITLE: ^ Examination of Ultrasound Measured Tissue Perfusion on Breast Cancer...Examination of Ultrasound Measured Tissue Perfusion on Breast Cancer 3. REPORT TYPE AND DATES COVERED Final (1 Jun 94 - 30 Nov 98) 5. FUNDING

Diaphragm breathing movement measurement using ultrasound and radiographic imaging: a concurrent validity.

PubMed

Noh, Dong K; Lee, Jae J; You, Joshua H

2014-01-01

Recent ultrasound imaging evidence asserts that the diaphragm is an important multifunctional muscle to control breathing as well as stabilize the core and posture in humans. However, the validity and accuracy of ultrasound for the measurement of dynamic diaphragm movements during breathing and functional core activities have not been determined. The specific aim of this study was to validate the accuracy of ultrasound imaging measurements of diaphragm movements by concurrently comparing these measurements to the gold standard of radiographic imaging measurements. A total of 14 asymptomatic adults (9 males, 5 females; mean age =28.4 ± 3.0 years) were recruited to participate in the study. Ultrasound and radiographic images were used concurrently to determine diaphragm movement (inspiration, expiration, and excursion) during tidal breathing. Pearson correlation analysis showed strong correlations, ranging from r=0.78 to r=0.83, between ultrasound and radiographic imaging measurements of the diaphragm during inhalation, exhalation, and excursion. These findings suggest that ultrasound imaging measurement is useful to accurately evaluate diaphragm movements during tidal breathing. Clinically, ultrasound imaging measurements can be used to diagnose and treat diaphragm movement impairments in individuals with neuromuscular disorders including spinal cord injuries, stroke, and multiple sclerosis.

Quantitative evaluation of hidden defects in cast iron components using ultrasound activated lock-in vibrothermography.

PubMed

Montanini, R; Freni, F; Rossi, G L

2012-09-01

This paper reports one of the first experimental results on the application of ultrasound activated lock-in vibrothermography for quantitative assessment of buried flaws in complex cast parts. The use of amplitude modulated ultrasonic heat generation allowed selective response of defective areas within the part, as the defect itself is turned into a local thermal wave emitter. Quantitative evaluation of hidden damages was accomplished by estimating independently both the area and the depth extension of the buried flaws, while x-ray 3D computed tomography was used as reference for sizing accuracy assessment. To retrieve flaw's area, a simple yet effective histogram-based phase image segmentation algorithm with automatic pixels classification has been developed. A clear correlation was found between the thermal (phase) signature measured by the infrared camera on the target surface and the actual mean cross-section area of the flaw. Due to the very fast cycle time (<30 s/part), the method could potentially be applied for 100% quality control of casting components.

Development of a Duplex Ultrasound Simulator and Preliminary Validation of Velocity Measurements in Carotid Artery Models.

PubMed

Zierler, R Eugene; Leotta, Daniel F; Sansom, Kurt; Aliseda, Alberto; Anderson, Mark D; Sheehan, Florence H

2016-07-01

in the velocity measurement of less than 10%. With the addition of cases with a range of pathologies, this duplex ultrasound simulator will be a useful tool for training health-care providers in vascular ultrasound applications and for assessing their skills in an objective and quantitative manner. © The Author(s) 2016.

Mechanical Model Analysis for Quantitative Evaluation of Liver Fibrosis Based on Ultrasound Tissue Elasticity Imaging

NASA Astrophysics Data System (ADS)

Shiina, Tsuyoshi; Maki, Tomonori; Yamakawa, Makoto; Mitake, Tsuyoshi; Kudo, Masatoshi; Fujimoto, Kenji

2012-07-01

Precise evaluation of the stage of chronic hepatitis C with respect to fibrosis has become an important issue to prevent the occurrence of cirrhosis and to initiate appropriate therapeutic intervention such as viral eradication using interferon. Ultrasound tissue elasticity imaging, i.e., elastography can visualize tissue hardness/softness, and its clinical usefulness has been studied to detect and evaluate tumors. We have recently reported that the texture of elasticity image changes as fibrosis progresses. To evaluate fibrosis progression quantitatively on the basis of ultrasound tissue elasticity imaging, we introduced a mechanical model of fibrosis progression and simulated the process by which hepatic fibrosis affects elasticity images and compared the results with those clinical data analysis. As a result, it was confirmed that even in diffuse diseases like chronic hepatitis, the patterns of elasticity images are related to fibrous structural changes caused by hepatic disease and can be used to derive features for quantitative evaluation of fibrosis stage.

Quantitative contrast-enhanced ultrasound imaging: a review of sources of variability

PubMed Central

Tang, M.-X.; Mulvana, H.; Gauthier, T.; Lim, A. K. P.; Cosgrove, D. O.; Eckersley, R. J.; Stride, E.

2011-01-01

Ultrasound provides a valuable tool for medical diagnosis offering real-time imaging with excellent spatial resolution and low cost. The advent of microbubble contrast agents has provided the additional ability to obtain essential quantitative information relating to tissue vascularity, tissue perfusion and even endothelial wall function. This technique has shown great promise for diagnosis and monitoring in a wide range of clinical conditions such as cardiovascular diseases and cancer, with considerable potential benefits in terms of patient care. A key challenge of this technique, however, is the existence of significant variations in the imaging results, and the lack of understanding regarding their origin. The aim of this paper is to review the potential sources of variability in the quantification of tissue perfusion based on microbubble contrast-enhanced ultrasound images. These are divided into the following three categories: (i) factors relating to the scanner setting, which include transmission power, transmission focal depth, dynamic range, signal gain and transmission frequency, (ii) factors relating to the patient, which include body physical differences, physiological interaction of body with bubbles, propagation and attenuation through tissue, and tissue motion, and (iii) factors relating to the microbubbles, which include the type of bubbles and their stability, preparation and injection and dosage. It has been shown that the factors in all the three categories can significantly affect the imaging results and contribute to the variations observed. How these factors influence quantitative imaging is explained and possible methods for reducing such variations are discussed. PMID:22866229

Quantitative analysis for peripheral vascularity assessment based on clinical photoacoustic and ultrasound images

NASA Astrophysics Data System (ADS)

Murakoshi, Dai; Hirota, Kazuhiro; Ishii, Hiroyasu; Hashimoto, Atsushi; Ebata, Tetsurou; Irisawa, Kaku; Wada, Takatsugu; Hayakawa, Toshiro; Itoh, Kenji; Ishihara, Miya

2018-02-01

Photoacoustic (PA) imaging technology is expected to be applied to clinical assessment for peripheral vascularity. We started a clinical evaluation with the prototype PA imaging system we recently developed. Prototype PA imaging system was composed with in-house Q-switched Alexandrite laser system which emits short-pulsed laser with 750 nm wavelength, handheld ultrasound transducer where illumination optics were integrated and signal processing for PA image reconstruction implemented in the clinical ultrasound (US) system. For the purpose of quantitative assessment of PA images, an image analyzing function has been developed and applied to clinical PA images. In this analyzing function, vascularity derived from PA signal intensity ranged for prescribed threshold was defined as a numerical index of vessel fulfillment and calculated for the prescribed region of interest (ROI). Skin surface was automatically detected by utilizing B-mode image acquired simultaneously with PA image. Skinsurface position is utilized to place the ROI objectively while avoiding unwanted signals such as artifacts which were imposed due to melanin pigment in the epidermal layer which absorbs laser emission and generates strong PA signals. Multiple images were available to support the scanned image set for 3D viewing. PA images for several fingers of patients with systemic sclerosis (SSc) were quantitatively assessed. Since the artifact region is trimmed off in PA images, the visibility of vessels with rather low PA signal intensity on the 3D projection image was enhanced and the reliability of the quantitative analysis was improved.

Comparative evaluation of ultrasound scanner accuracy in distance measurement

NASA Astrophysics Data System (ADS)

Branca, F. P.; Sciuto, S. A.; Scorza, A.

2012-10-01

The aim of the present study is to develop and compare two different automatic methods for accuracy evaluation in ultrasound phantom measurements on B-mode images: both of them give as a result the relative error e between measured distances, performed by 14 brand new ultrasound medical scanners, and nominal distances, among nylon wires embedded in a reference test object. The first method is based on a least squares estimation, while the second one applies the mean value of the same distance evaluated at different locations in ultrasound image (same distance method). Results for both of them are proposed and explained.

The influence of dairy consumption and physical activity on ultrasound bone measurements in Flemish children.

PubMed

De Smet, Stephanie; Michels, Nathalie; Polfliet, Carolien; D'Haese, Sara; Roggen, Inge; De Henauw, Stefaan; Sioen, Isabelle

2015-03-01

The study's aim was to analyse whether children's bone status, assessed by calcaneal ultrasound measurements, is influenced by dairy consumption and objectively measured physical activity (PA). Moreover, the interaction between dairy consumption and PA on bone mass was studied. Participants of this cross-sectional study were 306 Flemish children (6-12 years). Body composition was measured with air displacement plethysmography (BodPod), dairy consumption with a Food Frequency Questionnaire, PA with an accelerometer (only in 234 of the 306 children) and bone mass with quantitative ultrasound, quantifying speed of sound (SOS), broadband ultrasound attenuation (BUA) and Stiffness Index (SI). Regression analyses were used to study the associations between dairy consumption, PA, SOS, BUA and SI. Total dairy consumption and non-cheese dairy consumption were positively associated with SOS and SI, but no significant association could be demonstrated with BUA. In contrast, milk consumption, disregarding other dairy products, had no significant effect on calcaneal bone measurements. PA [vigorous PA, moderate to vigorous physical activity (MVPA) and counts per minute] was positively associated and sedentary time was negatively associated with BUA and SI, but no significant influence on SOS could be detected. Dairy consumption and PA (sedentary time and MVPA) did not show any interaction influencing bone measurements. In conclusion, even at young age, PA and dairy consumption positively influence bone mass. Promoting PA and dairy consumption in young children may, therefore, maximize peak bone mass, an important protective factor against osteoporosis later in life.

Measuring Femoral Torsion In Vivo Using Freehand 3-D Ultrasound Imaging.

PubMed

Passmore, Elyse; Pandy, Marcus G; Graham, H Kerr; Sangeux, Morgan

2016-02-01

Despite variation in bone geometry, muscle and joint function is often investigated using generic musculoskeletal models. Patient-specific bone geometry can be obtained from computerised tomography, which involves ionising radiation, or magnetic resonance imaging (MRI), which is costly and time consuming. Freehand 3-D ultrasound provides an alternative to obtain bony geometry. The purpose of this study was to determine the accuracy and repeatability of 3-D ultrasound in measuring femoral torsion. Measurements of femoral torsion were performed on 10 healthy adults using MRI and 3-D ultrasound. Measurements of femoral torsion from 3-D ultrasound were, on average, smaller than those from MRI (mean difference = 1.8°; 95% confidence interval: -3.9°, 7.5°). MRI and 3-D ultrasound had Bland and Altman repeatability coefficients of 3.1° and 3.7°, respectively. Accurate measurements of femoral torsion were obtained with 3-D ultrasound offering the potential to acquire patient-specific bone geometry for musculoskeletal modelling. Three-dimensional ultrasound is non-invasive and relatively inexpensive and can be integrated into gait analysis. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

A hybrid FDTD-Rayleigh integral computational method for the simulation of the ultrasound measurement of proximal femur.

PubMed

Cassereau, Didier; Nauleau, Pierre; Bendjoudi, Aniss; Minonzio, Jean-Gabriel; Laugier, Pascal; Bossy, Emmanuel; Grimal, Quentin

2014-07-01

The development of novel quantitative ultrasound (QUS) techniques to measure the hip is critically dependent on the possibility to simulate the ultrasound propagation. One specificity of hip QUS is that ultrasounds propagate through a large thickness of soft tissue, which can be modeled by a homogeneous fluid in a first approach. Finite difference time domain (FDTD) algorithms have been widely used to simulate QUS measurements but they are not adapted to simulate ultrasonic propagation over long distances in homogeneous media. In this paper, an hybrid numerical method is presented to simulate hip QUS measurements. A two-dimensional FDTD simulation in the vicinity of the bone is coupled to the semi-analytic calculation of the Rayleigh integral to compute the wave propagation between the probe and the bone. The method is used to simulate a setup dedicated to the measurement of circumferential guided waves in the cortical compartment of the femoral neck. The proposed approach is validated by comparison with a full FDTD simulation and with an experiment on a bone phantom. For a realistic QUS configuration, the computation time is estimated to be sixty times less with the hybrid method than with a full FDTD approach. Copyright © 2013 Elsevier B.V. All rights reserved.

Phalangeal quantitative ultrasound and metabolic control in pre-menopausal women with type 1 diabetes mellitus.

PubMed

Catalano, A; Morabito, N; Di Vieste, G; Pintaudi, B; Cucinotta, D; Lasco, A; Di Benedetto, A

2013-05-01

Several studies have reported increased fracture risk in Type 1 diabetes mellitus (T1DM). Quantitative Ultrasound (QUS) provides information on the structure and elastic properties of bone, which are important determinants of fracture risk, along with bone mineral density. To study phalangeal sites by QUS, examine bone turnover markers and analyze association between these factors with metabolic control in a population of pre-menopausal women with T1DM. Thirty-five T1DM pre-menopausal women (mean age 34.5 ± 6.8 yr) attending the Diabetic Outpatients Clinic in the Department of Internal Medicine, University of Messina, were consecutively enrolled and divided into two groups, taking into account the mean value of glycated hemoglobin in the last three years. Twenty healthy age-matched women served as controls. Phalangeal ultrasound measurements [Amplitude Dependent Speed of Sound (AD-SoS), Ultrasound Bone Profile Index (UBPI), TScore, Z-Score] were performed using a DBM Sonic Bone Profiler. Osteocalcin and deoxypyridinoline served as markers of bone formation and bone resorption, respectively. T1DM women with poor metabolic control showed lower phalangeal QUS values compared to healthy controls (p<0.01) and T1DM women with good metabolic control (p<0.05). No significant differences in QUS measurements were detected between T1DM women with good metabolic control and healthy controls. Lower bone formation and increased bone resorption, although not statistically significant, were observed in patients with poor metabolic control in comparison to patients with good metabolic control. Poor metabolic control may worsen the quality of bone in T1DM. Phalangeal QUS could be considered as a tool to screen T1DM women for osteoporosis in pre-menopausal age.

Higher tibial quantitative ultrasound in young female swimmers.

PubMed

Falk, B; Bronshtein, Z; Zigel, L; Constantini, N; Eliakim, A

2004-08-01

It has been found that swimming, a non-impact sport, generally has no effect on bone mineral density. To examine bone properties, as measured by quantitative ultrasound, among female swimmers in comparison with control girls and women. Subjects included 61 swimmers and 71 controls aged 8.5 to 26.5 years. None of the swimmers was at the elite level and none had included resistance training in her schedule. Bone speed of sound (SOS) was measured bilaterally at the distal radius and the mid-tibia. No differences were observed between swimmers and controls in body mass (mean (SD): 49.7 (12.3) v 50.7 (12.4) kg, respectively), although swimmers were taller (159 (12) v 155 (12) cm) and had lower body fat (18.3 (4.2)% v 22.3 (5.4)%). No difference was found in time since menarche (5.2 (4.0) and 4.5 (2.9) years in swimmers and controls, respectively; 21 swimmers and 25 control were premenarcheal). Radial speed of sound (SOS) increased with age but did not differ between swimmers and controls (non-dominant: 3904 (172) and 3889 (165) m/s for swimmers and controls, respectively). Tibial SOS also increased with age and was significantly higher in swimmers than in controls (non-dominant: 3774 (155) v 3712 (171) m/s). No differences were found between dominant and non-dominant sides. Swimming appears to be associated with higher bone SOS in the lower but not in the upper extremities. Further studies are needed to assess whether this difference reflects higher habitual activity among the swimmers or swimming specific mechanisms.

Quantitative ultrasound imaging for monitoring in situ high-intensity focused ultrasound exposure.

PubMed

Ghoshal, Goutam; Kemmerer, Jeremy P; Karunakaran, Chandra; Abuhabsah, Rami; Miller, Rita J; Sarwate, Sandhya; Oelze, Michael L

2014-10-01

Quantitative ultrasound (QUS) imaging is hypothesized to map temperature elevations induced in tissue with high spatial and temporal resolution. To test this hypothesis, QUS techniques were examined to monitor high-intensity focused ultrasound (HIFU) exposure of tissue. In situ experiments were conducted on mammary adenocarcinoma tumors grown in rats and lesions were formed using a HIFU system. A thermocouple was inserted into the tumor to provide estimates of temperature at one location. Backscattered time-domain waveforms from the tissue during exposure were recorded using a clinical ultrasonic imaging system. Backscatter coefficients were estimated using a reference phantom technique. Two parameters were estimated from the backscatter coefficient (effective scatterer diameter (ESD) and effective acoustic concentration (EAC). The changes in the average parameters in the regions corresponding to the HIFU focus over time were correlated to the temperature readings from the thermocouple. The changes in the EAC parameter were consistently correlated to temperature during both heating and cooling of the tumors. The changes in the ESD did not have a consistent trend with temperature. The mean ESD and EAC before exposure were 120 ± 16 μm and 32 ± 3 dB/cm3, respectively, and changed to 144 ± 9 μm and 51 ± 7 dB/cm3, respectively, just before the last HIFU pulse was delivered to the tissue. After the tissue cooled down to 37 °C, the mean ESD and EAC were 126 ± 8 μm and 35 ± 4 dB/cm3, respectively. Peak temperature in the range of 50-60 °C was recorded by a thermocouple placed just behind the tumor. These results suggest that QUS techniques have the potential to be used for non-invasive monitoring of HIFU exposure. © The Author(s) 2014.

Ultrasound elastography: the new frontier in direct measurement of muscle stiffness.

PubMed

Brandenburg, Joline E; Eby, Sarah F; Song, Pengfei; Zhao, Heng; Brault, Jeffrey S; Chen, Shigao; An, Kai-Nan

2014-11-01

The use of brightness-mode ultrasound and Doppler ultrasound in physical medicine and rehabilitation has increased dramatically. The continuing evolution of ultrasound technology has also produced ultrasound elastography, a cutting-edge technology that can directly measure the mechanical properties of tissue, including muscle stiffness. Its real-time and direct measurements of muscle stiffness can aid the diagnosis and rehabilitation of acute musculoskeletal injuries and chronic myofascial pain. It can also help monitor outcomes of interventions affecting muscle in neuromuscular and musculoskeletal diseases, and it can better inform the functional prognosis. This technology has implications for even broader use of ultrasound in physical medicine and rehabilitation practice, but more knowledge about its uses and limitations is essential to its appropriate clinical implementation. In this review, we describe different ultrasound elastography techniques for studying muscle stiffness, including strain elastography, acoustic radiation force impulse imaging, and shear-wave elastography. We discuss the basic principles of these techniques, including the strengths and limitations of their measurement capabilities. We review the current muscle research, discuss physiatric clinical applications of these techniques, and note directions for future research. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Ultrasound Elastography: The New Frontier in Direct Measurement of Muscle Stiffness

PubMed Central

Brandenburg, Joline E.; Eby, Sarah F.; Song, Pengfei; Zhao, Heng; Brault, Jeffrey S.; Chen, Shigao; An, Kai-Nan

2014-01-01

The use of brightness-mode ultrasound and Doppler ultrasound in physical medicine and rehabilitation has increased dramatically. The continuing evolution of ultrasound technology has also produced ultrasound elastography, a cutting-edge technology that can directly measure the mechanical properties of tissue, including muscle stiffness. Its real-time and direct measurements of muscle stiffness can aid the diagnosis and rehabilitation of acute musculoskeletal injuries and chronic myofascial pain. It can also help monitor outcomes of interventions affecting muscle in neuromuscular and musculoskeletal diseases, and it can better inform the functional prognosis. This technology has implications for even broader use of ultrasound in physical medicine and rehabilitation practice, but more knowledge about its uses and limitations is essential to its appropriate clinical implementation. In this review, we describe different ultrasound elastography techniques for studying muscle stiffness, including strain elastography, acoustic radiation force impulse imaging, and shear-wave elastography. We discuss the basic principles of these techniques, including the strengths and limitations of their measurement capabilities. We review the current muscle research, discuss physiatric clinical applications of these techniques, and note directions for future research. PMID:25064780

Value of Quantitative Three-dimensional Doppler Ultrasound in the Differentiation of Benign and Malignant Thyroid Nodules.

PubMed

Li, Wen-Bo; Zhang, Bo; Jiang, Yu-Xin; Zhu, Qing-Li; Zhang, Qing; Sun, Jian

2015-06-01

To investigate the role of quantitative three-dimensional (3D) power Doppler ultrasound in differentiating malignant and benign thyroid nodule. A total of 92 lesions in 86 patients were preoperatively examined using 3D power Doppler ultrasound. The Virtual Organ Computer-aided Analysis(VOCAL)-imaging program was used to analyze the stored volume ultrasound. The differences in the mean gray value (MG), vascularization index (VI), flow index(FI), and vascularization flow index (VFI) were compared between benign and malignant lesions. The MG of the malignant thyroid nodules was significantly lower than that of the benign ones (28.27±7.21 vs. 32.89±8.73,P=0.007). The benign nodules had significantly higher VI,FI,and VFI than the malignant nodules [VI:(40.43±26.55)% vs. (26.87±23.06)%,P=0.011;FI:41.03±7.19 vs. 37.51±7.17,P=0.022;VFI:18.23±14.60 vs. 11.47±12.47, P=0.009]. Also,76.5% (39/51) of the malignant nodules and 92.7% (38/41) of the benign nodules had higher VIs in the shell of the lesion than that of the whole lesion,and 80.4%(41/51) of the malignant nodules and 95.1% (39/41) of the benign nodules had higher FIs in the shell of the lesion than that of the whole lesion. Quantitative 3D power Doppler ultrasound provides a useful tool in distinguishing benign and malignant thyroid nodules. The malignant thyroid nodules have lower echoes than the benign nodules, wherese the benign nodules have larger blood flow than the malignant nodules.

An ergonomic, instrumented ultrasound probe for 6-axis force/torque measurement.

PubMed

Gilbertson, Matthew W; Anthony, Brian W

2013-01-01

An ergonomic, instrumented ultrasound probe has been developed for medical imaging applications. The device, which fits compactly in the hand of sonographers and permits rapid attachment & removal of the ultrasound probe, measures ultrasound probe-to-patient contact forces and torques in all six axes. The device was used to measure contact forces and torques applied by ten professional sonographers on five patients during thirty-six abdominal exams. Of the three contact forces, those applied along the probe axis were found to be largest, averaging 7.0N. Measurement noise was quantified for each axis, and found to be small compared with the axial force. Understanding the range of forces applied during ultrasound imaging enables the design of more accurate robotic imaging systems and could also improve understanding of the correlation between contact force and sonographer fatigue and injury.

Investigation of a dual modal method for bone pathologies using quantitative ultrasound and photoacoustics

NASA Astrophysics Data System (ADS)

Steinberg, Idan; Gannot, Israel; Eyal, Avishay

2015-03-01

Osteoporosis is a widespread disease that has a catastrophic impact on patient's lives and overwhelming related healthcare costs. In recent works, we have developed a multi-spectral, frequency domain photoacoustic method for the evaluation of bone pathologies. This method has great advantages over pure ultrasonic or optical methods as it provides both molecular information from the bone absorption spectrum and bone mechanical status from the characteristics of the ultrasound propagation. These characteristics include both the Speed of Sound (SOS) and Broadband Ultrasonic Attenuation (BUA). To test the method's quantitative predictions, we have constructed a combined ultrasound and photoacoustic setup. Here, we experimentally present a dual modality system, and compares between the methods on bone samples in-vitro. The differences between the two modalities are shown to provide valuable insight into the bone structure and functional status.

Comparison of Diagnostic Performance of Semi-Quantitative Knee Ultrasound and Knee Radiography with MRI: Oulu Knee Osteoarthritis Study.

PubMed

Podlipská, Jana; Guermazi, Ali; Lehenkari, Petri; Niinimäki, Jaakko; Roemer, Frank W; Arokoski, Jari P; Kaukinen, Päivi; Liukkonen, Esa; Lammentausta, Eveliina; Nieminen, Miika T; Tervonen, Osmo; Koski, Juhani M; Saarakkala, Simo

2016-03-01

Osteoarthritis (OA) is a common degenerative musculoskeletal disease highly prevalent in aging societies worldwide. Traditionally, knee OA is diagnosed using conventional radiography. However, structural changes of articular cartilage or menisci cannot be directly evaluated using this method. On the other hand, ultrasound is a promising tool able to provide direct information on soft tissue degeneration. The aim of our study was to systematically determine the site-specific diagnostic performance of semi-quantitative ultrasound grading of knee femoral articular cartilage, osteophytes and meniscal extrusion, and of radiographic assessment of joint space narrowing and osteophytes, using MRI as a reference standard. Eighty asymptomatic and 79 symptomatic subjects with mean age of 57.7 years were included in the study. Ultrasound performed best in the assessment of femoral medial and lateral osteophytes, and medial meniscal extrusion. In comparison to radiography, ultrasound performed better or at least equally well in identification of tibio-femoral osteophytes, medial meniscal extrusion and medial femoral cartilage morphological degeneration. Ultrasound provides relevant additional diagnostic information on tissue-specific morphological changes not depicted by conventional radiography. Consequently, the use of ultrasound as a complementary imaging tool along with radiography may enable more accurate and cost-effective diagnostics of knee osteoarthritis at the primary healthcare level.

Dual-plane ultrasound flow measurements in liquid metals

NASA Astrophysics Data System (ADS)

Büttner, Lars; Nauber, Richard; Burger, Markus; Räbiger, Dirk; Franke, Sven; Eckert, Sven; Czarske, Jürgen

2013-05-01

An ultrasound measurement system for dual-plane, two-component flow velocity measurements especially in opaque liquids is presented. Present-day techniques for measuring local flow structures in opaque liquids disclose considerable drawbacks concerning line-wise measurement of single ultrasound probes. For studying time-varying flow patterns, conventional ultrasound techniques are either limited by time-consuming mechanical traversing or by the sequential operation of single probes. The measurement system presented within this paper employs four transducer arrays with a total of 100 single elements which allows for flow mapping without mechanical traversing. A high frame rate of several 10 Hz has been achieved due to an efficient parallelization scheme using time-division multiplexing realized by a microcontroller-based electronic switching matrix. The functionality and capability of the measurement system are demonstrated on a liquid metal flow at room temperature inside a cube driven by a rotating magnetic field (RMF). For the first time, the primary and the secondary flow have been studied in detail and simultaneously using a configuration with two crossed measurement planes. The experimental data confirm predictions made by numeric simulation. After a sudden switching on of the RMF, inertial oscillations of the secondary flow were observed by means of a time-resolved measurement with a frame rate of 3.4 Hz. The experiments demonstrate that the presented measurement system is able to investigate complex and transient flow structures in opaque liquids. Due to its ability to study the temporal evolution of local flow structures, the measurement system could provide considerable progress for fluid dynamics research, in particular for applications in the food industry or liquid metal technologies.

Reliability and validity of quantifying absolute muscle hardness using ultrasound elastography.

PubMed

Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

2012-01-01

Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young's moduli of seven tissue-mimicking materials (in vitro; Young's modulus range, 20-80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young's modulus ratio of two reference materials, one hard and one soft (Young's moduli of 7 and 30 kPa, respectively), the Young's moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young's moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young's moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified.

Automatic measurement of pennation angle and fascicle length of gastrocnemius muscles using real-time ultrasound imaging.

PubMed

Zhou, Guang-Quan; Chan, Phoebe; Zheng, Yong-Ping

2015-03-01

Muscle imaging is a promising field of research to understand the biological and bioelectrical characteristics of muscles through the observation of muscle architectural change. Sonomyography (SMG) is a technique which can quantify the real-time architectural change of muscles under different contractions and motions with ultrasound imaging. The pennation angle and fascicle length are two crucial SMG parameters to understand the contraction mechanics at muscle level, but they have to be manually detected on ultrasound images frame by frame. In this study, we proposed an automatic method to quantitatively identify pennation angle and fascicle length of gastrocnemius (GM) muscle based on multi-resolution analysis and line feature extraction, which could overcome the limitations of tedious and time-consuming manual measurement. The method started with convolving Gabor wavelet specially designed for enhancing the line-like structure detection in GM ultrasound image. The resulting image was then used to detect the fascicles and aponeuroses for calculating the pennation angle and fascicle length with the consideration of their distribution in ultrasound image. The performance of this method was tested on computer simulated images and experimental images in vivo obtained from normal subjects. Tests on synthetic images showed that the method could identify the fascicle orientation with an average error less than 0.1°. The result of in vivo experiment showed a good agreement between the results obtained by the automatic and the manual measurements (r=0.94±0.03; p<0.001, and r=0.95±0.02, p<0.001). Furthermore, a significant correlation between the ankle angle and pennation angle (r=0.89±0.05; p<0.001) and fascicle length (r=-0.90±0.04; p<0.001) was found for the ankle plantar flexion. This study demonstrated that the proposed method was able to automatically measure the pennation angle and fascicle length of GM ultrasound images, which made it feasible to investigate

An investigation of the use of transmission ultrasound to measure acoustic attenuation changes in thermal therapy.

PubMed

Parmar, Neeta; Kolios, Michael C

2006-07-01

The potential of using a commercial ultrasound transmission imaging system to quantitatively monitor tissue attenuation changes after thermal therapy was investigated. The ultrasound transmission imaging system used, the AcoustoCam (Imperium Inc., MD) allows ultrasonic images to be captured using principles similar to that of a CCD-type camera that collects light. Ultrasound energy is focused onto a piezoelectric array by an acoustic lens system, creating a gray scale acoustic image. In this work, the pixel values from the acoustic images were assigned acoustic attenuation values by imaging polyacrylamide phantoms of varying known attenuation. After the calibration procedure, data from heated polyacrylamide/bovine serum albumin (BSA) based tissue-mimicking (TM) phantoms and porcine livers were acquired. Samples were heated in water at temperatures of 35, 45, 55, 65, and 75 degrees C for 1 h. Regions of interest were chosen in the images and acoustic attenuation values before and after heating were compared. An increase in ultrasound attenuation was found in phantoms containing BSA and in porcine liver. In the presence of BSA, attenuation in the TM phantom increased by a factor of 1.5, while without BSA no significant changes were observed. The attenuation of the porcine liver increased by up to a factor of 2.4, consistent with previously reported studies. The study demonstrates the feasibility of using a quantitative ultrasound transmission imaging system for monitoring thermal therapy.

Breast-Lesion Characterization using Textural Features of Quantitative Ultrasound Parametric Maps.

PubMed

Sadeghi-Naini, Ali; Suraweera, Harini; Tran, William Tyler; Hadizad, Farnoosh; Bruni, Giancarlo; Rastegar, Rashin Fallah; Curpen, Belinda; Czarnota, Gregory J

2017-10-20

This study evaluated, for the first time, the efficacy of quantitative ultrasound (QUS) spectral parametric maps in conjunction with texture-analysis techniques to differentiate non-invasively benign versus malignant breast lesions. Ultrasound B-mode images and radiofrequency data were acquired from 78 patients with suspicious breast lesions. QUS spectral-analysis techniques were performed on radiofrequency data to generate parametric maps of mid-band fit, spectral slope, spectral intercept, spacing among scatterers, average scatterer diameter, and average acoustic concentration. Texture-analysis techniques were applied to determine imaging biomarkers consisting of mean, contrast, correlation, energy and homogeneity features of parametric maps. These biomarkers were utilized to classify benign versus malignant lesions with leave-one-patient-out cross-validation. Results were compared to histopathology findings from biopsy specimens and radiology reports on MR images to evaluate the accuracy of technique. Among the biomarkers investigated, one mean-value parameter and 14 textural features demonstrated statistically significant differences (p < 0.05) between the two lesion types. A hybrid biomarker developed using a stepwise feature selection method could classify the legions with a sensitivity of 96%, a specificity of 84%, and an AUC of 0.97. Findings from this study pave the way towards adapting novel QUS-based frameworks for breast cancer screening and rapid diagnosis in clinic.

Ultrasound transmission measurements for tensile strength evaluation of tablets.

PubMed

Simonaho, Simo-Pekka; Takala, T Aleksi; Kuosmanen, Marko; Ketolainen, Jarkko

2011-05-16

Ultrasound transmission measurements were performed to evaluate the tensile strength of tablets. Tablets consisting of one ingredient were compressed from dibasic calcium phosphate dehydrate, two grades of microcrystalline cellulose and two grades of lactose monohydrate powders. From each powder, tablets with five different tensile strengths were directly compressed. Ultrasound transmission measurements were conducted on every tablet at frequencies of 2.25 MHz, 5 MHz and 10 MHz and the speed of sound was calculated from the acquired waveforms. The tensile strength of the tablets was determined using a diametrical mechanical testing machine and compared to the calculated speed of sound values. It was found that the speed of sound increased with the tensile strength for the tested excipients. There was a good correlation between the speed of sound and tensile strength. Moreover, based on the statistical tests, the groups with different tensile strengths can be differentiated from each other by measuring the speed of sound. Thus, the ultrasound transmission measurement technique is a potentially useful method for non-destructive and fast evaluation of the tensile strength of tablets. Copyright © 2011 Elsevier B.V. All rights reserved.

Ultrasound elastography: principles, techniques, and clinical applications.

PubMed

Dewall, Ryan J

2013-01-01

Ultrasound elastography is an emerging set of imaging modalities used to image tissue elasticity and are often referred to as virtual palpation. These techniques have proven effective in detecting and assessing many different pathologies, because tissue mechanical changes often correlate with tissue pathological changes. This article reviews the principles of ultrasound elastography, many of the ultrasound-based techniques, and popular clinical applications. Originally, elastography was a technique that imaged tissue strain by comparing pre- and postcompression ultrasound images. However, new techniques have been developed that use different excitation methods such as external vibration or acoustic radiation force. Some techniques track transient phenomena such as shear waves to quantitatively measure tissue elasticity. Clinical use of elastography is increasing, with applications including lesion detection and classification, fibrosis staging, treatment monitoring, vascular imaging, and musculoskeletal applications.

Refining enamel thickness measurements from B-mode ultrasound images.

PubMed

Hua, Jeremy; Chen, Ssu-Kuang; Kim, Yongmin

2009-01-01

Dental erosion has been growing increasingly prevalent with the rise in consumption of heavy starches, sugars, coffee, and acidic beverages. In addition, various disorders, such as Gastroenterological Reflux Disease (GERD), have symptoms of rapid rates of tooth erosion. The measurement of enamel thickness would be important for dentists to assess the progression of enamel loss from all forms of erosion, attrition, and abrasion. Characterizing enamel loss is currently done with various subjective indexes that can be interpreted in different ways by different dentists. Ultrasound has been utilized since the 1960s to determine internal tooth structure, but with mixed results. Via image processing and enhancement, we were able to refine B-mode dental ultrasound images for more accurate enamel thickness measurements. The mean difference between the measured thickness of the occlusal enamel from ultrasound images and corresponding gold standard CT images improved from 0.55 mm to 0.32 mm with image processing (p = 0.033). The difference also improved from 0.62 to 0.53 mm at the buccal/lingual enamel surfaces, but not significantly (p = 0.38).

Site-specific ultrasound reflection properties and superficial collagen content of bovine knee articular cartilage

NASA Astrophysics Data System (ADS)

Laasanen, Mikko S.; Saarakkala, Simo; Töyräs, Juha; Rieppo, Jarno; Jurvelin, Jukka S.

2005-07-01

Previous quantitative 2D-ultrasound imaging studies have demonstrated that the ultrasound reflection measurement of articular cartilage surface sensitively detects degradation of the collagen network, whereas digestion of cartilage proteoglycans has no significant effect on the ultrasound reflection. In this study, the first aim was to characterize the ability of quantitative 2D-ultrasound imaging to detect site-specific differences in ultrasound reflection and backscattering properties of cartilage surface and cartilage-bone interface at visually healthy bovine knee (n = 30). As a second aim, we studied factors controlling ultrasound reflection properties of an intact cartilage surface. The ultrasound reflection coefficient was determined in time (R) and frequency domains (IRC) at medial femoral condyle, lateral patello-femoral groove, medial tibial plateau and patella using a 20 MHz ultrasound imaging instrument. Furthermore, cartilage surface roughness was quantified by calculating the ultrasound roughness index (URI). The superficial collagen content of the cartilage was determined using a FT-IRIS-technique. A significant site-dependent variation was shown in cartilage thickness, ultrasound reflection parameters, URI and superficial collagen content. As compared to R and IRC, URI was a more sensitive parameter in detecting differences between the measurement sites. Ultrasound reflection parameters were not significantly related to superficial collagen content, whereas the correlation between R and URI was high. Ultrasound reflection at the cartilage-bone interface showed insignificant site-dependent variation. The current results suggest that ultrasound reflection from the intact cartilage surface is mainly dependent on the cartilage surface roughness and the collagen content has a less significant role.

The RSPO3 gene as genetic markers for bone mass assessed by quantitative ultrasound in a population of young adults.

PubMed

Correa-Rodríguez, María; Schmidt Rio-Valle, Jacqueline; Rueda-Medina, Blanca

2018-05-01

Ultrasound bone mass measurement has been postulated as a valuable bone-health assessment tool for primary care. The aim of this study was to analyse the possible relationship between the SPTBN1, RSPO3, CCDC170, DKK1, GPATCH1, and TMEM135 genes, with calcaneal quantitative ultrasound (QUS) in a population of young adults. These genes were first associated with broadband ultrasound attenuation (BUA) in the GEFOS/GENOMOS study. A cross-sectional study was conducted on 575 individuals (mean age 20.41 ± 2.69). Bone mass at the right calcaneus was estimated by QUS. Six single-nucleotide polymorphisms (SNPs) in SPTBN1 (rs11898505), RSPO3 (rs7741021), CCDC170 (rs4869739), DKK1 (rs7902708), TMEM135 (rs597319), and GPATCH1 (rs10416265) were selected as genetic markers based on their previous association with calcaneal QUS. After adjusting for multiple confounding factors, the only significant association with QUS in our population was found for the rs7741021 SNP in the RSPO3 gene (P = 0.006) using the dominant model of inheritance. This suggests the possible implication of the RSPO3 gene in bone mass acquisition during early adulthood. © 2017 John Wiley & Sons Ltd/University College London.

Regional repeatability measures of corneal thickness: Orbscan II and ultrasound.

PubMed

Jonuscheit, Sven; Doughty, Michael J

2007-01-01

To compare repeatability of the measures of corneal thickness obtained by slit-scanning light method (Orbscan II) with those obtained by an ultrasound pachymeter, with special interest in the peripheral region of the cornea. On 24 normal adults, aged 20 to 58 years (average 36 years) with up to -8.5 DS refractive error, three measures of corneal thickness were taken using Orbscan II and then by ultrasound pachymetry (under topical anesthesia with benoxinate 0.4%). The Orbscan central sample zone of 1 mm was selected, or the numerical maps were used to extract single point data along the horizontal corneal meridian to the nasal and temporal sides out to 4.5 mm. Ultrasound readings were taken from the central cornea and at the periphery just inside the limbus (4.5 mm from center) with a 2.4-mm diameter probe. For a central 1-mm diameter zone, the coefficient of variation (CV) for three consecutive corneal thickness measures was 0.81%+/-0.44%, but was marginally higher (p=0.004), if just the central single point data was taken with Orbscan (0.86%+/-0.45%). Similar repeatability was noted for the numerical output across the temporal side along the horizontal meridian out to 2.5 mm from the center, but farther out to 4 mm and on the nasal side the repeatability was slightly less and around 1.0% (p<0.001). Orbscan point readings of thickness could only sometimes be obtained at 4.5 mm temporally (with a poorer CV of 1.32%) and very rarely at 4.5 mm on the nasal side. No absolute differences in Orbscan repeatability were noted when comparing emmetropic with myopic subjects (p>or=0.5). Ultrasound pachymetry readings across the central zone were repeatable to 0.82%+/-0.67%. When measured with the edge of the ultrasound probe just touching the limbus, the repeatability of ultrasound readings was 1.37%+/-1.10% temporally and 1.49%+/-1.02% nasally, but neither was statistically worse that the most peripheral readings for Orbscan (p>or=0.210). However, it was also noted that the

Combining Ultrasound Pulse-Echo and Transmission Computed Tomography for Quantitative Imaging the Cortical Shell of Long Bone Replicas

NASA Astrophysics Data System (ADS)

Shortell, Matthew P.; Althomali, Marwan A. M.; Wille, Marie-Luise; Langton, Christian M.

2017-11-01

We demonstrate a simple technique for quantitative ultrasound imaging of the cortical shell of long bone replicas. Traditional ultrasound computed tomography instruments use the transmitted or reflected waves for separate reconstructions but suffer from strong refraction artefacts in highly heterogenous samples such as bones in soft tissue. The technique described here simplifies the long bone to a two-component composite and uses both the transmitted and reflected waves for reconstructions, allowing the speed of sound and thickness of the cortical shell to be calculated accurately. The technique is simple to implement, computationally inexpensive and sample positioning errors are minimal.

Measurement of fetal head descent using the 'angle of progression' on transperineal ultrasound imaging is reliable regardless of fetal head station or ultrasound expertise.

PubMed

Dückelmann, A M; Bamberg, C; Michaelis, S A M; Lange, J; Nonnenmacher, A; Dudenhausen, J W; Kalache, K D

2010-02-01

To assess whether ultrasound experience or fetal head station affects the reliability of measurement of fetal head descent using the angle of progression on intrapartum ultrasound images obtained by a single experienced operator, and to determine reliability of measurements when images were acquired by different operators with variable ultrasound experience. One experienced obstetrician performed 44 transperineal ultrasound examinations of women at term and in prolonged second stage of labor with the fetus in the occipitoanterior position. Three midwives without ultrasound experience, three obstetricians with < 5 years' experience and three obstetricians with > 10 years' experience measured fetal head descent based on the angle of progression in the images obtained. The angle of progression was measured by two obstetricians in independent ultrasound examinations of 24 laboring women at term with the fetus in the cephalic position to allow assessment of the reliability of image acquisition. Intraclass correlation coefficients (ICCs) with 95% confidence interval (CI) were used to evaluate interobserver reliability and Bland-Altman analysis was used to assess interobserver agreement. In total, 444 measurements were performed and compared. Interobserver reliability with respect to offline image analysis was substantial (overall ICC, 0.72; 95% CI, 0.63-0.81). ICCs were 0.82 (95% CI, 0.70-0.89), 0.81 (95% CI, 0.71-0.88) and 0.61 (95% CI, 0.43-074) for observers with > 10 years', < 5 years' and no ultrasound experience, respectively. There were no significant differences between ICCs among observer groups according to ultrasound experience. Fetal head station did not affect reliability. Bland-Altman analysis indicated reasonable agreement between measurements obtained by two different operators with > 10 years' and < 5 years' ultrasound experience (bias, -1.09 degrees ; 95% limits of agreement, -8.76 to 6.58). The reliability of measurement of the angle of progression

Sex hormones and quantitative ultrasound parameters at the heel in men and women from the general population.

PubMed

Pätzug, Konrad; Friedrich, Nele; Kische, Hanna; Hannemann, Anke; Völzke, Henry; Nauck, Matthias; Keevil, Brian G; Haring, Robin

2017-12-01

The present study investigates potential associations between liquid chromatography-mass spectrometry (LC-MS) measured sex hormones, dehydroepiandrosterone sulphate, sex hormone-binding globulin (SHBG) and bone ultrasound parameters at the heel in men and women from the general population. Data from 502 women and 425 men from the population-based Study of Health in Pomerania (SHIP-TREND) were used. Cross-sectional associations of sex hormones including testosterone (TT), calculated free testosterone (FT), dehydroepiandrosterone sulphate (DHEAS), androstenedione (ASD), estrone (E1) and SHBG with quantitative ultrasound (QUS) parameters at the heel, including broadband ultrasound attenuation (BUA), speed of sound (SOS) and stiffness index (SI) were examined by analysis of variance (ANOVA) and multivariable quantile regression models. Multivariable regression analysis showed a sex-specific inverse association of DHEAS with SI in men (Beta per SI unit = - 3.08, standard error (SE) = 0.88), but not in women (Beta = - 0.01, SE = 2.09). Furthermore, FT was positively associated with BUA in men (Beta per BUA unit = 29.0, SE = 10.1). None of the other sex hormones (ASD, E1) or SHBG was associated with QUS parameters after multivariable adjustment. This cross-sectional population-based study revealed independent associations of DHEAS and FT with QUS parameters in men, suggesting a potential influence on male bone metabolism. The predictive role of DHEAS and FT as a marker for osteoporosis in men warrants further investigation in clinical trials and large-scale observational studies.

Using ultrasound to quantify tongue shape and movement characteristics.

PubMed

Zharkova, Natalia

2013-01-01

Objective : Previous experimental studies have demonstrated abnormal lingual articulatory patterns characterizing cleft palate speech. Most articulatory information to date has been collected using electropalatography, which records the location and size of tongue-palate contact but not the tongue shape. The latter type of data can be provided by ultrasound. The present paper aims to describe ultrasound tongue imaging as a potential tool for quantitative analysis of tongue function in speakers with cleft palate. A description of the ultrasound technique as applied to analyzing tongue movements is given, followed by the requirements for quantitative analysis. Several measures are described, and example calculations are provided. Measures : Two measures aim to quantify overuse of tongue dorsum in cleft palate articulations. Crucially for potential clinical applications, these measures do not require head-to-transducer stabilization because both are based on a single tongue curve. The other three measures compare sets of tongue curves, with the aim to quantify the dynamics of tongue displacement, token-to-token variability in tongue position, and the extent of separation between tongue curves for different speech sounds. Conclusions : All measures can be used to compare tongue function in speakers with cleft palate before and after therapy, as well as to assess their performance against that in typical speakers and to help in selecting more effective treatments.

Association of quantitative magnetic resonance imaging parameters with histological findings from MRI/ultrasound fusion prostate biopsy.

PubMed

Dianat, Seyed Saeid; Carter, H Ballentine; Schaeffer, Edward M; Hamper, Ulrik M; Epstein, Jonathan I; Macura, Katarzyna J

2015-10-01

Purpose of this pilot study was to correlate quantitative parameters derived from the multiparametric magnetic resonance imaging (MP-MRI) of the prostate with results from MRI guided transrectal ultrasound (MRI/TRUS) fusion prostate biopsy in men with suspected prostate cancer. Thirty-nine consecutive patients who had 3.0T MP-MRI and subsequent MRI/TRUS fusion prostate biopsy were included and 73 MRI-identified targets were sampled by 177 cores. The pre-biopsy MP-MRI consisted of T2-weighted, diffusion weighted (DWI), and dynamic contrast enhanced (DCE) images. The association of quantitative MRI measurements with biopsy histopathology findings was assessed by Mann-Whitney U- test and Kruskal-Wallis test. Of 73 targets, biopsy showed benign prostate tissue in 46 (63%), cancer in 23 (31.5%), and atypia/high grade prostatic intraepithelial neoplasia in four (5.5%) targets. The median volume of cancer-positive targets was 1.3 cm3. The cancer-positive targets were located in the peripheral zone (56.5%), transition zone (39.1%), and seminal vesicle (4.3%). Nine of 23 (39.1%) cancer-positive targets were higher grade cancer (Gleason grade > 6). Higher grade targets and cancer-positive targets compared to benign lesions exhibited lower mean apparent diffusion coefficient (ADC) value (952.7 < 1167.9 < 1278.9), and lower minimal extracellular volume fraction (ECF) (0.13 < 0.185 < 0.213), respectively. The difference in parameters was more pronounced between higher grade cancer and benign lesions. Our findings from a pilot study indicate that quantitative MRI parameters can predict malignant histology on MRI/TRUS fusion prostate biopsy, which is a valuable technique to ensure adequate sampling of MRI-visible suspicious lesions under TRUS guidance and may impact patient management. The DWI-based quantitative measurement exhibits a stronger association with biopsy findings than the other MRI parameters.

Reliability and Validity of Quantifying Absolute Muscle Hardness Using Ultrasound Elastography

PubMed Central

Chino, Kentaro; Akagi, Ryota; Dohi, Michiko; Fukashiro, Senshi; Takahashi, Hideyuki

2012-01-01

Muscle hardness is a mechanical property that represents transverse muscle stiffness. A quantitative method that uses ultrasound elastography for quantifying absolute human muscle hardness has been previously devised; however, its reliability and validity have not been completely verified. This study aimed to verify the reliability and validity of this quantitative method. The Young’s moduli of seven tissue-mimicking materials (in vitro; Young’s modulus range, 20–80 kPa; increments of 10 kPa) and the human medial gastrocnemius muscle (in vivo) were quantified using ultrasound elastography. On the basis of the strain/Young’s modulus ratio of two reference materials, one hard and one soft (Young’s moduli of 7 and 30 kPa, respectively), the Young’s moduli of the tissue-mimicking materials and medial gastrocnemius muscle were calculated. The intra- and inter-investigator reliability of the method was confirmed on the basis of acceptably low coefficient of variations (≤6.9%) and substantially high intraclass correlation coefficients (≥0.77) obtained from all measurements. The correlation coefficient between the Young’s moduli of the tissue-mimicking materials obtained using a mechanical method and ultrasound elastography was 0.996, which was equivalent to values previously obtained using magnetic resonance elastography. The Young’s moduli of the medial gastrocnemius muscle obtained using ultrasound elastography were within the range of values previously obtained using magnetic resonance elastography. The reliability and validity of the quantitative method for measuring absolute muscle hardness using ultrasound elastography were thus verified. PMID:23029231

Epidemiological survey of the feasibility of broadband ultrasound attenuation measured using calcaneal quantitative ultrasound to predict the incidence of falls in the middle aged and elderly.

PubMed

Ou, Ling-Chun; Chang, Yin-Fan; Chang, Chin-Sung; Chiu, Ching-Ju; Chao, Ting-Hsing; Sun, Zih-Jie; Lin, Ruey-Mo; Wu, Chih-Hsing

2017-01-09

We investigated whether calcaneal quantitative ultrasound (QUS-C) is a feasible tool for predicting the incidence of falls. Prospective epidemiological cohort study. Community-dwelling people sampled in central western Taiwan. A cohort of community-dwelling people who were ≥40 years old (men: 524; women: 676) in 2009-2010. Follow-up questionnaires were completed by 186 men and 257 women in 2012. Structured questionnaires and broadband ultrasound attenuation (BUA) data were obtained in 2009-2010 using QUS-C, and follow-up surveys were done in a telephone interview in 2012. Using a binary logistic regression model, the risk factors associated with a new fall during follow-up were analysed with all significant variables from the bivariate comparisons and theoretically important variables. The incidence of falls was determined when the first new fall occurred during the follow-up period. The mean follow-up time was 2.83 years. The total incidence of falls was 28.0 per 1000 person-years for the ≥40 year old group (all participants), 23.3 per 1000 person-years for the 40-70 year old group, and 45.6 per 1000 person-years for the ≥70 year old group. Using multiple logistic regression models, the independent factors were current smoking, living alone, psychiatric drug usage and lower BUA (OR 0.93; 95% CI 0.88 to 0.99, p<0.05) in the ≥70 year old group. The incidence of falls was highest in the ≥70 year old group. Using QUS-C-derived BUA is feasible for predicting the incidence of falls in community-dwelling elderly people aged ≥70 years. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

NASA Technical Reports Server (NTRS)

Ueno, Toshiaki; Ballard, R. E.; Yost, W. T.; Hargens, A. R.

1997-01-01

Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

Development of Ultrasound to Measure In-Vivo Dynamic Cervical Spine Intervertebral Disc Mechanics

DTIC Science & Technology

2016-01-01

Award Number: W81XWH-13-1-0050 TITLE: Development of Ultrasound to Measure In-vivo Dynamic Cervical Spine Intervertebral Disc Mechanics PRINCIPAL...CONTRACT NUMBER W81XWH-13-1-0050 Development of Ultrasound to Measure In-vivo Dynamic Cervical Spine Intervertebral Disc Mechanics 5b. GRANT NUMBER 5c...elasticity during compression or tension. As a portable, low cost imaging modality, the dual ultrasound system quantified cervical spine IVD displacement and

Comparison of breast density measurements made using ultrasound tomography and mammography

NASA Astrophysics Data System (ADS)

Sak, Mark; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Krycia, Mark; Sherman, Mark E.; Boyd, Norman; Gierach, Gretchen L.

2015-03-01

Women with elevated mammographic percent density, defined as the ratio of fibroglandular tissue area to total breast area on a mammogram are at an increased risk of developing breast cancer. Ultrasound tomography (UST) is an imaging modality that can create tomographic sound speed images of a patient's breast, which can then be used to measure breast density. These sound speed images are useful because physical tissue density is directly proportional to sound speed. The work presented here updates previous results that compared mammographic breast density measurements with UST breast density measurements within an ongoing study. The current analysis has been expanded to include 158 women with negative digital mammographic screens who then underwent a breast UST scan. Breast density was measured for both imaging modalities and preliminary analysis demonstrated strong and positive correlations (Spearman correlation coefficient rs = 0.703). Additional mammographic and UST related imaging characteristics were also analyzed and used to compare the behavior of both imaging modalities. Results suggest that UST can be used among women with negative mammographic screens as a quantitative marker of breast density that may avert shortcomings of mammography.

Steato-Score: Non-Invasive Quantitative Assessment of Liver Fat by Ultrasound Imaging.

PubMed

Di Lascio, Nicole; Avigo, Cinzia; Salvati, Antonio; Martini, Nicola; Ragucci, Monica; Monti, Serena; Prinster, Anna; Chiappino, Dante; Mancini, Marcello; D'Elia, Domenico; Ghiadoni, Lorenzo; Bonino, Ferruccio; Brunetto, Maurizia R; Faita, Francesco

2018-05-04

Non-alcoholic fatty liver disease is becoming a global epidemic. The aim of this study was to develop a system for assessing liver fat content based on ultrasound images. Magnetic resonance spectroscopy measurements were obtained in 61 patients and the controlled attenuation parameter in 54. Ultrasound images were acquired for all 115 participants and used to calculate the hepatic/renal ratio, hepatic/portal vein ratio, attenuation rate, diaphragm visualization and portal vein wall visualization. The Steato-score was obtained by combining these five parameters. Magnetic resonance spectroscopy measurements were significantly correlated with hepatic/renal ratio, hepatic/portal vein ratio, attenuation rate, diaphragm visualization and portal vein wall visualization; Steato-score was dependent on hepatic/renal ratio, attenuation rate and diaphragm visualization. Area under the receiver operating characteristic curve was equal to 0.98, with 89% sensitivity and 94% specificity. Controlled attenuation parameter values were significantly correlated with hepatic/renal ratio, attenuation rate, diaphragm visualization and Steato-score; the area under the curve was 0.79. This system could be a valid alternative as a non-invasive, simple and inexpensive assessment of intrahepatic fat. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

Estimation of polydispersity in aggregating red blood cells by quantitative ultrasound backscatter analysis.

PubMed

de Monchy, Romain; Rouyer, Julien; Destrempes, François; Chayer, Boris; Cloutier, Guy; Franceschini, Emilie

2018-04-01

Quantitative ultrasound techniques based on the backscatter coefficient (BSC) have been commonly used to characterize red blood cell (RBC) aggregation. Specifically, a scattering model is fitted to measured BSC and estimated parameters can provide a meaningful description of the RBC aggregates' structure (i.e., aggregate size and compactness). In most cases, scattering models assumed monodisperse RBC aggregates. This study proposes the Effective Medium Theory combined with the polydisperse Structure Factor Model (EMTSFM) to incorporate the polydispersity of aggregate size. From the measured BSC, this model allows estimating three structural parameters: the mean radius of the aggregate size distribution, the width of the distribution, and the compactness of the aggregates. Two successive experiments were conducted: a first experiment on blood sheared in a Couette flow device coupled with an ultrasonic probe, and a second experiment, on the same blood sample, sheared in a plane-plane rheometer coupled to a light microscope. Results demonstrated that the polydisperse EMTSFM provided the best fit to the BSC data when compared to the classical monodisperse models for the higher levels of aggregation at hematocrits between 10% and 40%. Fitting the polydisperse model yielded aggregate size distributions that were consistent with direct light microscope observations at low hematocrits.

Ultrasound hepatic/renal ratio and hepatic attenuation rate for quantifying liver fat content.

PubMed

Zhang, Bo; Ding, Fang; Chen, Tian; Xia, Liang-Hua; Qian, Juan; Lv, Guo-Yi

2014-12-21

To establish and validate a simple quantitative assessment method for nonalcoholic fatty liver disease (NAFLD) based on a combination of the ultrasound hepatic/renal ratio and hepatic attenuation rate. A total of 170 subjects were enrolled in this study. All subjects were examined by ultrasound and (1)H-magnetic resonance spectroscopy ((1)H-MRS) on the same day. The ultrasound hepatic/renal echo-intensity ratio and ultrasound hepatic echo-intensity attenuation rate were obtained from ordinary ultrasound images using the MATLAB program. Correlation analysis revealed that the ultrasound hepatic/renal ratio and hepatic echo-intensity attenuation rate were significantly correlated with (1)H-MRS liver fat content (ultrasound hepatic/renal ratio: r = 0.952, P = 0.000; hepatic echo-intensity attenuation r = 0.850, P = 0.000). The equation for predicting liver fat content by ultrasound (quantitative ultrasound model) is: liver fat content (%) = 61.519 × ultrasound hepatic/renal ratio + 167.701 × hepatic echo-intensity attenuation rate -26.736. Spearman correlation analysis revealed that the liver fat content ratio of the quantitative ultrasound model was positively correlated with serum alanine aminotransferase, aspartate aminotransferase, and triglyceride, but negatively correlated with high density lipoprotein cholesterol. Receiver operating characteristic curve analysis revealed that the optimal point for diagnosing fatty liver was 9.15% in the quantitative ultrasound model. Furthermore, in the quantitative ultrasound model, fatty liver diagnostic sensitivity and specificity were 94.7% and 100.0%, respectively, showing that the quantitative ultrasound model was better than conventional ultrasound methods or the combined ultrasound hepatic/renal ratio and hepatic echo-intensity attenuation rate. If the (1)H-MRS liver fat content had a value < 15%, the sensitivity and specificity of the ultrasound quantitative model would be 81.4% and 100%, which still shows that using

Evaluation and comparison of current fetal ultrasound image segmentation methods for biometric measurements: a grand challenge.

PubMed

Rueda, Sylvia; Fathima, Sana; Knight, Caroline L; Yaqub, Mohammad; Papageorghiou, Aris T; Rahmatullah, Bahbibi; Foi, Alessandro; Maggioni, Matteo; Pepe, Antonietta; Tohka, Jussi; Stebbing, Richard V; McManigle, John E; Ciurte, Anca; Bresson, Xavier; Cuadra, Meritxell Bach; Sun, Changming; Ponomarev, Gennady V; Gelfand, Mikhail S; Kazanov, Marat D; Wang, Ching-Wei; Chen, Hsiang-Chou; Peng, Chun-Wei; Hung, Chu-Mei; Noble, J Alison

2014-04-01

This paper presents the evaluation results of the methods submitted to Challenge US: Biometric Measurements from Fetal Ultrasound Images, a segmentation challenge held at the IEEE International Symposium on Biomedical Imaging 2012. The challenge was set to compare and evaluate current fetal ultrasound image segmentation methods. It consisted of automatically segmenting fetal anatomical structures to measure standard obstetric biometric parameters, from 2D fetal ultrasound images taken on fetuses at different gestational ages (21 weeks, 28 weeks, and 33 weeks) and with varying image quality to reflect data encountered in real clinical environments. Four independent sub-challenges were proposed, according to the objects of interest measured in clinical practice: abdomen, head, femur, and whole fetus. Five teams participated in the head sub-challenge and two teams in the femur sub-challenge, including one team who tackled both. Nobody attempted the abdomen and whole fetus sub-challenges. The challenge goals were two-fold and the participants were asked to submit the segmentation results as well as the measurements derived from the segmented objects. Extensive quantitative (region-based, distance-based, and Bland-Altman measurements) and qualitative evaluation was performed to compare the results from a representative selection of current methods submitted to the challenge. Several experts (three for the head sub-challenge and two for the femur sub-challenge), with different degrees of expertise, manually delineated the objects of interest to define the ground truth used within the evaluation framework. For the head sub-challenge, several groups produced results that could be potentially used in clinical settings, with comparable performance to manual delineations. The femur sub-challenge had inferior performance to the head sub-challenge due to the fact that it is a harder segmentation problem and that the techniques presented relied more on the femur's appearance.

Quantitative Magnetic Resonance Thermometry and Its Use with MR-Guided Focused Ultrasound

NASA Astrophysics Data System (ADS)

Pauly, Kim

2014-03-01

Focused ultrasound (FUS) uses a large area array, typically outside the body, that is geometrically or electronically focused to a point deep in the body. Such focusing provides amplification of the ultrasound intensity, thereby allowing heating of tissue to the point of coagulation at the focus, without damage to the intervening tissue. Guidance of FUS treatments deep in the body can be done quantitatively with magnetic resonance (MR) thermometry, termed MRgFUS. The physics behind MR thermometry lie in the changes in hydrogen bonding with temperature. As tissue temperature rises, hydrogen bonds break, allowing the return of the electron cloud to shield water protons, reducing the magnetic field seen by the protons, and the resonant frequency. The change in resonant frequency is -0.01 ppm per degree C and is the same for all aqueous tissues. The result of the shift in proton resonant frequency is seen in the phase of gradient echo images. Subtraction of the phase of images acquired before and during heating allows the removal of background phase from other sources, yielding quantitative temperature maps. Temperature standard deviations less than 1 degree C are readily achievable and thermal dose maps are easily calculated. Thermal dose is found from a conversion of the whole temperature-time curve to an equivalent number of minutes at 43 degrees C. A thermal dose of 240 minutes is often taken as the threshold for tissue damage. MR thermometry is complicated by the motion of the target tissue and/or motion of other organs such as occurs during respiration. More sophisticated algorithms than the simple baseline subtraction take advantage of the facts that motion can be repetitive (in the case of respiratory motion) and/or the fact that the focal region in MRgFUS is small, allowing for extraction of the heat from the phase profile without subtraction of a background phase.

Nonlinear optical microscopy and ultrasound imaging of human cervical structure

PubMed Central

Reusch, Lisa M.; Feltovich, Helen; Carlson, Lindsey C.; Hall, Gunnsteinn; Campagnola, Paul J.; Eliceiri, Kevin W.

2013-01-01

Abstract. The cervix softens and shortens as its collagen microstructure rearranges in preparation for birth, but premature change may lead to premature birth. The global preterm birth rate has not decreased despite decades of research, likely because cervical microstructure is poorly understood. Our group has developed a multilevel approach to evaluating the human cervix. We are developing quantitative ultrasound (QUS) techniques for noninvasive interrogation of cervical microstructure and corroborating those results with high-resolution images of microstructure from second harmonic generation imaging (SHG) microscopy. We obtain ultrasound measurements from hysterectomy specimens, prepare the tissue for SHG, and stitch together several hundred images to create a comprehensive view of large areas of cervix. The images are analyzed for collagen orientation and alignment with curvelet transform, and registered with QUS data, facilitating multiscale analysis in which the micron-scale SHG images and millimeter-scale ultrasound data interpretation inform each other. This novel combination of modalities allows comprehensive characterization of cervical microstructure in high resolution. Through a detailed comparative study, we demonstrate that SHG imaging both corroborates the quantitative ultrasound measurements and provides further insight. Ultimately, a comprehensive understanding of specific microstructural cervical change in pregnancy should lead to novel approaches to the prevention of preterm birth. PMID:23412434

Nonlinear optical microscopy and ultrasound imaging of human cervical structure

NASA Astrophysics Data System (ADS)

Reusch, Lisa M.; Feltovich, Helen; Carlson, Lindsey C.; Hall, Gunnsteinn; Campagnola, Paul J.; Eliceiri, Kevin W.; Hall, Timothy J.

2013-03-01

The cervix softens and shortens as its collagen microstructure rearranges in preparation for birth, but premature change may lead to premature birth. The global preterm birth rate has not decreased despite decades of research, likely because cervical microstructure is poorly understood. Our group has developed a multilevel approach to evaluating the human cervix. We are developing quantitative ultrasound (QUS) techniques for noninvasive interrogation of cervical microstructure and corroborating those results with high-resolution images of microstructure from second harmonic generation imaging (SHG) microscopy. We obtain ultrasound measurements from hysterectomy specimens, prepare the tissue for SHG, and stitch together several hundred images to create a comprehensive view of large areas of cervix. The images are analyzed for collagen orientation and alignment with curvelet transform, and registered with QUS data, facilitating multiscale analysis in which the micron-scale SHG images and millimeter-scale ultrasound data interpretation inform each other. This novel combination of modalities allows comprehensive characterization of cervical microstructure in high resolution. Through a detailed comparative study, we demonstrate that SHG imaging both corroborates the quantitative ultrasound measurements and provides further insight. Ultimately, a comprehensive understanding of specific microstructural cervical change in pregnancy should lead to novel approaches to the prevention of preterm birth.

Model based inversion of ultrasound data in composites

NASA Astrophysics Data System (ADS)

Roberts, R. A.

2018-04-01

Work is reported on model-based defect characterization in CFRP composites. The work utilizes computational models of ultrasound interaction with defects in composites, to determine 1) the measured signal dependence on material and defect properties (forward problem), and 2) an assessment of defect properties from analysis of measured ultrasound signals (inverse problem). Work is reported on model implementation for inspection of CFRP laminates containing multi-ply impact-induced delamination, in laminates displaying irregular surface geometry (roughness), as well as internal elastic heterogeneity (varying fiber density, porosity). Inversion of ultrasound data is demonstrated showing the quantitative extraction of delamination geometry and surface transmissivity. Additionally, data inversion is demonstrated for determination of surface roughness and internal heterogeneity, and the influence of these features on delamination characterization is examined. Estimation of porosity volume fraction is demonstrated when internal heterogeneity is attributed to porosity.

Objective breast tissue image classification using Quantitative Transmission ultrasound tomography

NASA Astrophysics Data System (ADS)

Malik, Bilal; Klock, John; Wiskin, James; Lenox, Mark

2016-12-01

Quantitative Transmission Ultrasound (QT) is a powerful and emerging imaging paradigm which has the potential to perform true three-dimensional image reconstruction of biological tissue. Breast imaging is an important application of QT and allows non-invasive, non-ionizing imaging of whole breasts in vivo. Here, we report the first demonstration of breast tissue image classification in QT imaging. We systematically assess the ability of the QT images’ features to differentiate between normal breast tissue types. The three QT features were used in Support Vector Machines (SVM) classifiers, and classification of breast tissue as either skin, fat, glands, ducts or connective tissue was demonstrated with an overall accuracy of greater than 90%. Finally, the classifier was validated on whole breast image volumes to provide a color-coded breast tissue volume. This study serves as a first step towards a computer-aided detection/diagnosis platform for QT.

Correlation between Parameters of Calcaneal Quantitative Ultrasound and Hip Structural Analysis in Osteoporotic Fracture Patients

PubMed Central

Zheng, Hailiang; Li, Ming; Yin, Pengbin; Peng, Ye; Gao, Yuan; Zhang, Lihai; Tang, Peifu

2015-01-01

Background Calcaneal quantitative ultrasound (QUS), which is used in the evaluation of osteoporosis, is believed to be intimately associated with the characteristics of the proximal femur. However, the specific associations of calcaneal QUS with characteristics of the hip sub-regions remain unclear. Design A cross-sectional assessment of 53 osteoporotic patients was performed for the skeletal status of the heel and hip. Methods We prospectively enrolled 53 female osteoporotic patients with femoral fractures. Calcaneal QUS, dual energy X-ray absorptiometry (DXA), and hip structural analysis (HSA) were performed for each patient. Femoral heads were obtained during the surgery, and principal compressive trabeculae (PCT) were extracted by a three-dimensional printing technique-assisted method. Pearson’s correlation between QUS measurement with DXA, HSA-derived parameters and Young’s modulus were calculated in order to evaluate the specific association of QUS with the parameters for the hip sub-regions, including the femoral neck, trochanteric and Ward’s areas, and the femoral shaft, respectively. Results Significant correlations were found between estimated BMD (Est.BMD) and BMD of different sub-regions of proximal femur. However, the correlation coefficient of trochanteric area (r = 0.356, p = 0.009) was higher than that of the neck area (r = 0.297, p = 0.031) and total proximal femur (r = 0.291, p = 0.034). Furthermore, the quantitative ultrasound index (QUI) was significantly correlated with the HSA-derived parameters of the trochanteric area (r value: 0.315–0.356, all p<0.05) as well as with the Young’s modulus of PCT from the femoral head (r = 0.589, p<0.001). Conclusion The calcaneal bone had an intimate association with the trochanteric cancellous bone. To a certain extent, the parameters of the calcaneal QUS can reflect the characteristics of the trochanteric area of the proximal hip, although not specifically reflective of those of the femoral neck

Diffusing-wave spectroscopy in an inhomogeneous object: Local viscoelastic spectra from ultrasound-assisted measurement of correlation decay arising from the ultrasound focal volume

NASA Astrophysics Data System (ADS)

Chandran, R. Sriram; Sarkar, Saikat; Kanhirodan, Rajan; Roy, Debasish; Vasu, Ram Mohan

2014-07-01

We demonstrate diffusing-wave spectroscopy (DWS) in a localized region of a viscoelastically inhomogeneous object by measurement of the intensity autocorrelation [g2(τ)] that captures only the decay introduced by the temperature-induced Brownian motion in the region. The region is roughly specified by the focal volume of an ultrasound transducer which introduces region specific mechanical vibration owing to insonification. Essential characteristics of the localized non-Markovian dynamics are contained in the decay of the modulation depth [M(τ)], introduced by the ultrasound forcing in the focal volume selected, on g2(τ). The modulation depth M (τi) at any delay time τi can be measured by short-time Fourier transform of g2(τ) and measurement of the magnitude of the spectrum at the ultrasound drive frequency. By following the established theoretical framework of DWS, we are able to connect the decay in M (τ) to the mean-squared displacement (MSD) of scattering centers and the MSD to G*(ω), the complex viscoelastic spectrum. A two-region composite polyvinyl alcohol phantom with different viscoelastic properties is selected for demonstrating local DWS-based recovery of G*(ω) corresponding to these regions from the measured region specific M (τi)vsτi. The ultrasound-assisted measurement of MSD is verified by simulating, using a generalized Langevin equation (GLE), the dynamics of the particles in the region selected as well as by the usual DWS experiment without the ultrasound. It is shown that whereas the MSD obtained by solving the GLE without the ultrasound forcing agreed with its experimental counterpart covering small and large values of τ, the match was good only in the initial transients in regard to experimental measurements with ultrasound.

Quantitative contrast-enhanced ultrasound for monitoring vedolizumab therapy in inflammatory bowel disease patients: a pilot study.

PubMed

Goertz, Ruediger S; Klett, Daniel; Wildner, Dane; Atreya, Raja; Neurath, Markus F; Strobel, Deike

2018-01-01

Background Microvascularization of the bowel wall can be visualized and quantified non-invasively by software-assisted analysis of derived time-intensity curves. Purpose To perform software-based quantification of bowel wall perfusion using quantitative contrast-enhanced ultrasound (CEUS) according to clinical response in patients with inflammatory bowel disease treated with vedolizumab. Material and Methods In a prospective study, in 18 out of 34 patients, high-frequency ultrasound of bowel wall thickness using color Doppler flow combined with CEUS was performed at baseline and after 14 weeks of treatment with vedolizumab. Clinical activity scores at week 14 were used to differentiate between responders and non-responders. CEUS parameters were calculated by software analysis of the video loops. Results Nine of 18 patients (11 with Crohn's disease and seven with ulcerative colitis) showed response to treatment with vedolizumab. Overall, the responder group showed a significant decrease in the semi-quantitative color Doppler vascularization score. Amplitude-derived CEUS parameters of mural microvascularization such as peak enhancement or wash-in rate decreased in responders, in contrast with non-responders. Time-derived parameters remained stable or increased during treatment in all patients. Conclusion Analysis of bowel microvascularization by CEUS shows statistically significant changes in the wash-in-rate related to response of vedolizumab therapy.

Metatarsophalangeal joint extension changes ultrasound measurements for plantar fascia thickness.

PubMed

Granado, Michael J; Lohman, Everett B; Gordon, Keith E; Daher, Noha S

2018-01-01

Ultrasound is an inexpensive method for quantifying plantar fascia thickness, especially in those with plantar fasciitis. Ultrasound has also been used to assess the effectiveness of various treatments for plantar fasciitis by comparing plantar fascia thickness before and after an intervention period. While a plantar fascia thickness over 4 mm via ultrasound has been proposed to be consistent with plantar fasciitis, some researchers believe the 4 mm plantar fascia thickness level to be a dubious guideline for diagnosing plantar fasciitis due to the lack of standardization of the measurement process for plantar fascia thickness. In particular, no universal guidelines exist on the positioning of the metatarsophalangeal (MTP) joints during the procedure and the literature also has inconsistent protocols. The purpose of this study is to investigate and compare the influence of MTP joint extension on plantar fascia thickness in healthy participants and those with unilateral plantar fasciitis. The plantar fascia thickness of forty participants (20 with unilateral plantar fasciitis and 20 control) was measured via ultrasound three times at three different MTP joint positions: 1) at rest, 2) 30° of extension from the plantar surface, and 3) maximal extension possible. The plantar fascia became significantly thinner as MTP joint extension increased in both the plantar fasciitis group ( p  < 0.001) and the control group ( p  < 0.001). In the plantar fasciitis group, the involved plantar fascia was 1.2 to 1.3 mm thicker (p < 0.001) than the uninvolved side depending on the MTP joint position. In the control group, the difference in plantar fascia thickness between the two sides was less than 0.1 mm ( p  < 0.92) at any MTP joint position. MTP joint position can influence the ultrasound measurement of plantar fascia thickness. It is recommended that plantar fascia thickness measurements be performed with the toes at rest. If MTP joints must be extended

Ultrasound SIV measurement of helical valvular flow behind the great saphenous vein

NASA Astrophysics Data System (ADS)

Park, Jun Hong; Kim, Jeong Ju; Lee, Sang Joon; Yeom, Eunseop; Experimental Fluid Mechanics Laboratory Team; LaboratoryMicrothermal; Microfluidic Measurements Collaboration

2017-11-01

Dysfunction of venous valve and induced secondary abnormal flow are closely associated with venous diseases. Thus, detailed analysis of venous valvular flow is invaluable from biological and medical perspectives. However, most previous studies on venous perivalvular flows were based on qualitative analyses. On the contrary, quantitative analysis on the perivalvular flows has not been fully understood yet. In this study, 3D valvular flows under in vitro and in vivo conditions were experimentally investigated using ultrasound speckle image velocimetry (SIV) for analyzing their flow characteristics. The results for in vitro model obtained by the SIV technique were compared with those derived by numerical simulation and color Doppler method to validate its measurement accuracy. Then blood flow in the human great saphenous vein was measured using the SIV with respect to the dimensionless index, helical intensity. The results obtained by the SIV method are well matched well with those obtained by the numerical simulation and color Doppler method. The hemodynamic characteristics of 3D valvular flows measured by the validated SIV method would be helpful in diagnosis of valve-related venous diseases. None.

Characterization of enzymatically induced degradation of articular cartilage using high frequency ultrasound

NASA Astrophysics Data System (ADS)

Töyräs, J.; Rieppo, J.; Nieminen, M. T.; Helminen, H. J.; Jurvelin, J. S.

1999-11-01

Ultrasound may provide a quantitative technique for the characterization of cartilage changes typical of early osteoarthrosis. In this study, specific changes in bovine articular cartilage were induced using collagenase and chondroitinase ABC, enzymes that selectively degrade collagen fibril network and digest proteoglycans, respectively. Changes in cartilage structure and properties were quantified using high frequency ultrasound, microscopic analyses and mechanical indentation tests. The ultrasound reflection coefficient of the physiological saline-cartilage interface (R1) decreased significantly (-96.4%, p<0.01) in the collagenase digested cartilage compared to controls. Also a significantly lower ultrasound velocity (-6.2%, p<0.01) was revealed after collagenase digestion. After chondroitinase ABC digestion, a new acoustic interface at the depth of the enzyme penetration front was detected. Cartilage thickness, as determined with ultrasound, showed a high, linear correlation (R = 0.943, n = 60, average difference 0.073 mm (4.0%)) with the thickness measured by the needle-probe method. Both enzymes induced a significant decrease in the Young's modulus of cartilage (p<0.01). Our results indicate that high frequency ultrasound provides a sensitive technique for the analysis of cartilage structure and properties. Possibly ultrasound may be utilized in vivo as a quantitative probe during arthroscopy.

Theoretical framework for quantitatively estimating ultrasound beam intensities using infrared thermography.

PubMed

Myers, Matthew R; Giridhar, Dushyanth

2011-06-01

In the characterization of high-intensity focused ultrasound (HIFU) systems, it is desirable to know the intensity field within a tissue phantom. Infrared (IR) thermography is a potentially useful method for inferring this intensity field from the heating pattern within the phantom. However, IR measurements require an air layer between the phantom and the camera, making inferences about the thermal field in the absence of the air complicated. For example, convection currents can arise in the air layer and distort the measurements relative to the phantom-only situation. Quantitative predictions of intensity fields based upon IR temperature data are also complicated by axial and radial diffusion of heat. In this paper, mathematical expressions are derived for use with IR temperature data acquired at times long enough that noise is a relatively small fraction of the temperature trace, but small enough that convection currents have not yet developed. The relations were applied to simulated IR data sets derived from computed pressure and temperature fields. The simulation was performed in a finite-element geometry involving a HIFU transducer sonicating upward in a phantom toward an air interface, with an IR camera mounted atop an air layer, looking down at the heated interface. It was found that, when compared to the intensity field determined directly from acoustic propagation simulations, intensity profiles could be obtained from the simulated IR temperature data with an accuracy of better than 10%, at pre-focal, focal, and post-focal locations. © 2011 Acoustical Society of America

Quantitative calcaneal ultrasound parameters and bone mineral density at final height in girls treated with depot gonadotrophin-releasing hormone agonist for central precocious puberty or idiopathic short stature.

PubMed

Kapteijns-van Kordelaar, Simone; Noordam, Kees; Otten, Barto; van den Bergh, Joop

2003-11-01

To evaluate the effect of gonadotrophin-releasing hormone (GnRH) agonist treatment on bone quality at final height, we studied girls with central precocious puberty (CPP) and with idiopathic short stature (ISS). A total of 25 Caucasian girls were included: group A (n=14) with idiopathic CPP (mean age at start 7.4 years) and group B (n=11) with ISS (mean age at start 11.7 years). Treatment duration was 3.8 and 1.7 years respectively. The quantitative ultrasound parameters (QUS) broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured at the calcaneus (UBIS 3000 device). Lumbar spine bone mineral density (BMD; L2-L4) was measured by dual energy X-ray absorptiometry (DXA) (Hologic QDR1000). Measurements were performed at final height and expressed as Z-scores corrected for bone age. Mean Z-scores of QUS parameters, areal BMD and volumetric BMD (BMDvol) were above -1 in both groups (group A: BUA Z-score -0.21, SOS Z-score -0.29, BMD Z-score 0.02, BMDvol Z-score 0.05, group B: BUA Z-score -0.93, SOS Z-score -0.40, BMD Z-score -0.86, BMDvol Z-score -0.68), although mean Z-scores of BUA and areal BMD in group B were significantly different from zero (P=0.03 and P=0.02 respectively). Mean Z-score BMDvol was not significantly different from zero (P=0.05), we found no significant difference between the groups for BMDvol (P=0.13). Although quantitative ultrasound parameters parameters and bone mineral density were normal in girls with central precocious puberty at final height after gonadotrophin-releasing hormone agonist treatment, mean Z-score for broadband ultrasound attenuation and areal bone mineral density were significantly different from zero and mean Z-score for volumetric bone mineral density was (just) not significantly different from zero in idiopathic short stature girls with normal puberty treated with gonadotrophin-releasing hormone agonists. Therefore we cannot say that this treatment is safe in these girls with regard to bone health.

A screening model for low bone mass in elderly Japanese men using quantitative ultrasound measurements: Fujiwara-Kyo Study.

PubMed

Minematsu, Akira; Hazaki, Kan; Harano, Akihiro; Iki, Masayuki; Fujita, Yuki; Okamoto, Nozomi; Kurumatani, Norio

2012-01-01

Screening for low bone mass is important to prevent fragility fractures in men as well as women, although men show a much lower prevalence of osteoporosis than women. The purpose of this study was to establish a screening model for low bone mineral density (BMD) using a quantitative ultrasound parameter and easily obtained objective indices for elderly Japanese men. We examined 1633 men (65-84 yr old) who were subjects of the Fujiwara-Kyo Study. Speed of sound (SOS) at the calcaneus was determined, and BMD was measured by dual-energy X-ray absorptiometry at the lumbar spine (LS), total hip (TH), and femoral neck (FN). Low BMD was defined as >1 standard deviation below the young adult mean, in accordance with World Health Organization criteria. We performed receiver operating characteristic (ROC) analysis to identify a better screening model incorporating SOS and determined the optimal cutoff value using Youden index. Prevalences of low BMD at the 3 skeletal sites were 27.8% (LS), 33.5% (TH), 48.6% (FN), and 43.3% at either LS or TH. The greatest area under the ROC curve (0.806, 95% confidence interval: 0.785-0.828) and smallest Akaike's information criterion were obtained in the multivariate model incorporating SOS, age, height, and weight for predicting low BMD at all skeletal sites. This model predicted low BMD at TH with the sensitivity of 0.726 and specificity of 0.739, whereas a similar model predicted low BMD at LS with much lower validity. We conclude that the multivariate model for TH could be used to screen for low BMD in elderly Japanese men. Copyright © 2012 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

Muscle ultrasound quantifies disease progression over time in infants and young boys with duchenne muscular dystrophy.

PubMed

Zaidman, Craig M; Malkus, Elizabeth C; Connolly, Anne M

2015-09-01

Quantitative muscle ultrasound (QUS) in boys with Duchenne muscular dystrophy (DMD) shows increased echointensity as muscle is replaced with fat and fibrosis. Studies of quantitative ultrasound in infants/young boys with DMD over time have not been reported. We used calibrated muscle backscatter (cMB), a reproducible measure of ultrasound echointensity, to quantify muscle pathology in 5 young boys with DMD (ages 0.5-2.8 years) over 17-29 months. We compared the results with repeated assessments of function (n = 4) and with muscle ultrasound images from a cross-section of 6 male controls (0.6-3.1 years). cMB in boys with DMD increased (worsened) over time (P < 0.001), whereas function improved. After age 2 years, cMB in most (4 of 5) boys with DMD was higher than in any control. QUS measures disease progression in young boys with DMD despite functional improvements. QUS could be employed as an outcome measure for serial assessment of young boys with DMD. © 2015 Wiley Periodicals, Inc.

Diagnostic image quality in gynaecological ultrasound: Who should measure it, what should we measure and how?

PubMed Central

Knapp, Karen

2013-01-01

Assessment of diagnostic image quality in gynaecological ultrasound is an important aspect of imaging department quality assurance. This may be addressed through audit, but who should undertake the audit, what should be measured and how, remains contentious. The aim of this study was to identify whether peer audit is a suitable method of assessing the diagnostic quality of gynaecological ultrasound images. Nineteen gynaecological ultrasound studies were independently assessed by six sonographers utilising a pilot version of an audit tool. Outcome measures were levels of inter-rater agreement using different data collection methods (binary scores, Likert scale, continuous scale), effect of ultrasound study difficulty on study score and whether systematic differences were present between reviewers of different clinical grades and length of experience. Inter-rater agreement ranged from moderate to good depending on the data collection method. A continuous scale gave the highest level of inter-rater agreement with an intra-class correlation coefficient of 0.73. A strong correlation (r = 0.89) between study difficulty and study score was yielded. Length of clinical experience between reviewers had no effect on the audit scores, but individuals of a higher clinical grade gave significantly lower scores than those of a lower grade (p = 0.04). Peer audit is a promising tool in the assessment of ultrasound image quality. Continuous scales seem to be the best method of data collection implying a strong element of heuristically driven decision making by reviewing ultrasound practitioners. PMID:27433192

TU-H-CAMPUS-IeP3-04: Evaluation of Changes in Quantitative Ultrasound Parameters During Prostate Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Najafi, M; El Kaffas, A; Han, B

Purpose: Clarity Autoscan ultrasound monitoring system allows acquisition of raw radiofrequency (RF) ultrasound data prior and during radiotherapy. This enables the computation of 3D Quantitative Ultrasound (QUS) tissue parametric maps from. We aim to evaluate whether QUS parameters undergo changes with radiotherapy and thus potentially be used as early predictors and/or markers of treatment response in prostate cancer patients. Methods: In-vivo evaluation was performed under IRB protocol to allow data collection in prostate patients treated with VMAT whereby prostate was imaged through the acoustic window of the perineum. QUS spectroscopy analysis was carried out by computing a tissue power spectrummore » normalized to the power spectrum obtained from a quartz to remove system transfer function effects. A ROI was selected within the 3D image volume of the prostate. Because longitudinal registration was optimal, the same features could be used to select ROIs at roughly the same location in images acquired on different days. Parametric maps were generated within the rectangular ROIs with window sizes that were approximately 8 times the wavelength of the ultrasound. The mid-band fit (MBF), spectral slope (SS) and spectral intercept (SI) QUS parameters were computed for each window within the ROI and displayed as parametric maps. Quantitative parameters were obtained by averaging each of the spectral parameters over the whole ROI. Results: Data was acquired for over 21 treatment fractions. Preliminary results show changes in the parametric maps. MBF values decreased from −33.9 dB to −38.7 dB from pre-treatment to the last day of treatment. The spectral slope increased from −1.1 a.u. to −0.5 a.u., and spectral intercept decreased from −28.2 dB to −36.3 dB over the 21 treatment regimen. Conclusion: QUS parametric maps change over the course of treatment which warrants further investigation in their potential use for treatment planning and predicting

Ultrasound Velocity Measurement in a Liquid Metal Electrode

PubMed Central

Perez, Adalberto; Kelley, Douglas H.

2015-01-01

A growing number of electrochemical technologies depend on fluid flow, and often that fluid is opaque. Measuring the flow of an opaque fluid is inherently more difficult than measuring the flow of a transparent fluid, since optical methods are not applicable. Ultrasound can be used to measure the velocity of an opaque fluid, not only at isolated points, but at hundreds or thousands of points arrayed along lines, with good temporal resolution. When applied to a liquid metal electrode, ultrasound velocimetry involves additional challenges: high temperature, chemical activity, and electrical conductivity. Here we describe the experimental apparatus and methods that overcome these challenges and allow the measurement of flow in a liquid metal electrode, as it conducts current, at operating temperature. Temperature is regulated within ±2 °C using a Proportional-Integral-Derivative (PID) controller that powers a custom-built furnace. Chemical activity is managed by choosing vessel materials carefully and enclosing the experimental setup in an argon-filled glovebox. Finally, unintended electrical paths are carefully prevented. An automated system logs control settings and experimental measurements, using hardware trigger signals to synchronize devices. This apparatus and these methods can produce measurements that are impossible with other techniques, and allow optimization and control of electrochemical technologies like liquid metal batteries. PMID:26273726

Response monitoring of breast cancer patients receiving neoadjuvant chemotherapy using quantitative ultrasound, texture, and molecular features

PubMed Central

Gangeh, Mehrdad; Tadayyon, Hadi; Sadeghi-Naini, Ali; Gandhi, Sonal; Wright, Frances C.; Slodkowska, Elzbieta; Curpen, Belinda; Tran, William; Czarnota, Gregory J.

2018-01-01

Background Pathological response of breast cancer to chemotherapy is a prognostic indicator for long-term disease free and overall survival. Responses of locally advanced breast cancer in the neoadjuvant chemotherapy (NAC) settings are often variable, and the prediction of response is imperfect. The purpose of this study was to detect primary tumor responses early after the start of neoadjuvant chemotherapy using quantitative ultrasound (QUS), textural analysis and molecular features in patients with locally advanced breast cancer. Methods The study included ninety six patients treated with neoadjuvant chemotherapy. Breast tumors were scanned with a clinical ultrasound system prior to chemotherapy treatment, during the first, fourth and eighth week of treatment, and prior to surgery. Quantitative ultrasound parameters and scatterer-based features were calculated from ultrasound radio frequency (RF) data within tumor regions of interest. Additionally, texture features were extracted from QUS parametric maps. Prior to therapy, all patients underwent a core needle biopsy and histological subtypes and biomarker ER, PR, and HER2 status were determined. Patients were classified into three treatment response groups based on combination of clinical and pathological analyses: complete responders (CR), partial responders (PR), and non-responders (NR). Response classifications from QUS parameters, receptors status and pathological were compared. Discriminant analysis was performed on extracted parameters using a support vector machine classifier to categorize subjects into CR, PR, and NR groups at all scan times. Results Of the 96 patients, the number of CR, PR and NR patients were 21, 52, and 23, respectively. The best prediction of treatment response was achieved with the combination mean QUS values, texture and molecular features with accuracies of 78%, 86% and 83% at weeks 1, 4, and 8, after treatment respectively. Mean QUS parameters or clinical receptors status alone

Quantitative diagnostic method for biceps long head tendinitis by using ultrasound.

PubMed

Huang, Shih-Wei; Wang, Wei-Te

2013-01-01

To investigate the feasibility of grayscale quantitative diagnostic method for biceps tendinitis and determine the cut-off points of a quantitative biceps ultrasound (US) method to diagnose biceps tendinitis. Design. Prospective cross-sectional case controlled study. Outpatient rehabilitation service. A total of 336 shoulder pain patients with suspected biceps tendinitis were recruited in this prospective observational study. The grayscale pixel data of the range of interest (ROI) were obtained for both the transverse and longitudinal views of the biceps US. A total of 136 patients were classified with biceps tendinitis, and 200 patients were classified as not having biceps tendinitis based on the diagnostic criteria. Based on the Youden index, the cut-off points were determined as 26.85 for the transverse view and 21.25 for the longitudinal view of the standard deviation (StdDev) of the ROI values, respectively. When the ROI evaluation of the US surpassed the cut-off point, the sensitivity was 68% and the specificity was 90% in the StdDev of the transverse view, and the sensitivity was 81% and the specificity was 73% in the StdDev of the longitudinal view to diagnose biceps tendinitis. For equivocal cases or inexperienced sonographers, our study provides a more objective method for diagnosing biceps tendinitis in shoulder pain patients.

Estimation of Measurement Characteristics of Ultrasound Fetal Heart Rate Monitor

NASA Astrophysics Data System (ADS)

Noguchi, Yasuaki; Mamune, Hideyuki; Sugimoto, Suguru; Yoshida, Atsushi; Sasa, Hidenori; Kobayashi, Hisaaki; Kobayashi, Mitsunao

1995-05-01

Ultrasound fetal heart rate monitoring is very useful to determine the status of the fetus because it is noninvasive. In order to ensure the accuracy of the fetal heart rate (FHR) obtained from the ultrasound Doppler data, we measure the fetal electrocardiogram (ECG) directly and obtain the Doppler data simultaneously. The FHR differences of the Doppler data from the direct ECG data are concentrated at 0 bpm (beats per minute), and are practically symmetrical. The distribution is found to be very close to the Student's t distribution by the test of goodness of fit with the chi-square test. The spectral density of the FHR differences shows the white noise spectrum without any dominant peaks. Furthermore, the f-n (n>1) fluctuation is observed both with the ultrasound Doppler FHR and with the direct ECG FHR. Thus, it is confirmed that the FHR observation and observation of the f-n (n>1) fluctuation using the ultrasound Doppler FHR are as useful as the direct ECG.

Characterization of the Lung Parenchyma Using Ultrasound Multiple Scattering.

PubMed

Mohanty, Kaustav; Blackwell, John; Egan, Thomas; Muller, Marie

2017-05-01

The purpose of the study described here was to showcase the application of ultrasound to quantitative characterization of the micro-architecture of the lung parenchyma to predict the extent of pulmonary edema. The lung parenchyma is a highly complex and diffusive medium for which ultrasound techniques have remained qualitative. The approach presented here is based on ultrasound multiple scattering and exploits the complexity of ultrasound propagation in the lung structure. The experimental setup consisted of a linear transducer array with an 8-MHz central frequency placed in contact with the lung surface. The diffusion constant D and transport mean free path L* of the lung parenchyma were estimated by separating the incoherent and coherent intensities in the near field and measuring the growth of the incoherent diffusive halo over time. Significant differences were observed between the L* values obtained in healthy and edematous rat lungs in vivo. In the control rat lung, L* was found to be 332 μm (±48.8 μm), whereas in the edematous lung, it was 1040 μm (±90 μm). The reproducibility of the measurements of L* and D was tested in vivo and in phantoms made of melamine sponge with varying air volume fractions. Two-dimensional finite difference time domain numerical simulations were carried out on rabbit lung histology images with varying degrees of lung collapse. Significant correlations were observed between air volume fraction and L* in simulation (r = -0.9542, p < 0.0117) and sponge phantom (r = -0.9932, p < 0.0068) experiments. Ex vivo measurements of a rat lung in which edema was simulated by adding phosphate-buffered saline revealed a linear relationship between the fluid volume fraction and L*. These results illustrate the potential of methods based on ultrasound multiple scattering for the quantitative characterization of the lung parenchyma. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc

The use of the posture-p questionnaire and the quantitative ultrasound to assess the bone density of postmenopausal women

NASA Astrophysics Data System (ADS)

Winardi, A. M.; Wulansari, L. K.; Kusdhany, L. S.

2017-08-01

Osteoporosis must be detected early in order to prevent failures in denture treatment. To this end, tools such as the Posture-P questionnaire and the Quantitative Ultrasound (QUS) are widely used for osteoporosis screening. Posture-P. This study is a diagnostic test that analyzes the sensitivity and specificity of the Posture-P questionnaire towards QUS in assessing the bone density of postmenopausal women. Data was collected through interviews using the Posture-P questionnaire, and bone density was measured using the QUS. The results of this study show that both the sensitivity and specificity of the Posture-P questionnaire towards QUS are quite good, with respective values of 77.23% and 75%. Thus, the Posture-P questionnaire can replace the QUS in osteoporosis screening.

Comparative study of contrast-enhanced ultrasound qualitative and quantitative analysis for identifying benign and malignant breast tumor lumps.

PubMed

Liu, Jian; Gao, Yun-Hua; Li, Ding-Dong; Gao, Yan-Chun; Hou, Ling-Mi; Xie, Ting

2014-01-01

To compare the value of contrast-enhanced ultrasound (CEUS) qualitative and quantitative analysis in the identification of breast tumor lumps. Qualitative and quantitative indicators of CEUS for 73 cases of breast tumor lumps were retrospectively analyzed by univariate and multivariate approaches. Logistic regression was applied and ROC curves were drawn for evaluation and comparison. The CEUS qualitative indicator-generated regression equation contained three indicators, namely enhanced homogeneity, diameter line expansion and peak intensity grading, which demonstrated prediction accuracy for benign and malignant breast tumor lumps of 91.8%; the quantitative indicator-generated regression equation only contained one indicator, namely the relative peak intensity, and its prediction accuracy was 61.5%. The corresponding areas under the ROC curve for qualitative and quantitative analyses were 91.3% and 75.7%, respectively, which exhibited a statistically significant difference by the Z test (P<0.05). The ability of CEUS qualitative analysis to identify breast tumor lumps is better than with quantitative analysis.

Comparison of simulated and measured nonlinear ultrasound fields

NASA Astrophysics Data System (ADS)

Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt

2011-03-01

In this paper results from a non-linear AS (angular spectrum) based ultrasound simulation program are compared to water-tank measurements. A circular concave transducer with a diameter of 1 inch (25.4 mm) is used as the emitting source. The measured pulses are first compared with the linear simulation program Field II, which will be used to generate the source for the AS simulation. The generated non-linear ultrasound field is measured by a hydrophone in the focal plane. The second harmonic component from the measurement is compared with the AS simulation, which is used to calculate both fundamental and second harmonic fields. The focused piston transducer with a center frequency of 5 MHz is excited by a waveform generator emitting a 6-cycle sine wave. The hydrophone is mounted in the focal plane 118 mm from the transducer. The point spread functions at the focal depth from Field II and measurements are illustrated. The FWHM (full width at half maximum) values are 1.96 mm for the measurement and 1.84 mm for the Field II simulation. The fundamental and second harmonic components of the experimental results are plotted compared with the AS simulations. The RMS (root mean square) errors of the AS simulations are 7.19% and 10.3% compared with the fundamental and second harmonic components of the measurements.

Quantitative ultrasound assessment of breast tumor response to chemotherapy using a multi-parameter approach

PubMed Central

Tadayyon, Hadi; Sannachi, Lakshmanan; Gangeh, Mehrdad; Sadeghi-Naini, Ali; Tran, William; Trudeau, Maureen E.; Pritchard, Kathleen; Ghandi, Sonal; Verma, Sunil; Czarnota, Gregory J.

2016-01-01

Purpose This study demonstrated the ability of quantitative ultrasound (QUS) parameters in providing an early prediction of tumor response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer (LABC). Methods Using a 6-MHz array transducer, ultrasound radiofrequency (RF) data were collected from 58 LABC patients prior to NAC treatment and at weeks 1, 4, and 8 of their treatment, and prior to surgery. QUS parameters including midband fit (MBF), spectral slope (SS), spectral intercept (SI), spacing among scatterers (SAS), attenuation coefficient estimate (ACE), average scatterer diameter (ASD), and average acoustic concentration (AAC) were determined from the tumor region of interest. Ultrasound data were compared with the ultimate clinical and pathological response of the patient's tumor to treatment and patient recurrence-free survival. Results Multi-parameter discriminant analysis using the κ-nearest-neighbor classifier demonstrated that the best response classification could be achieved using the combination of MBF, SS, and SAS, with an accuracy of 60 ± 10% at week 1, 77 ± 8% at week 4 and 75 ± 6% at week 8. Furthermore, when the QUS measurements at each time (week) were combined with pre-treatment (week 0) QUS values, the classification accuracies improved (70 ± 9% at week 1, 80 ± 5% at week 4, and 81 ± 6% at week 8). Finally, the multi-parameter QUS model demonstrated a significant difference in survival rates of responding and non-responding patients at weeks 1 and 4 (p=0.035, and 0.027, respectively). Conclusion This study demonstrated for the first time, using new parameters tested on relatively large patient cohort and leave-one-out classifier evaluation, that a hybrid QUS biomarker including MBF, SS, and SAS could, with relatively high sensitivity and specificity, detect the response of LABC tumors to NAC as early as after 4 weeks of therapy. The findings of this study also suggested that incorporating pre-treatment QUS

Quantitative ultrasound assessment of breast tumor response to chemotherapy using a multi-parameter approach.

PubMed

Tadayyon, Hadi; Sannachi, Lakshmanan; Gangeh, Mehrdad; Sadeghi-Naini, Ali; Tran, William; Trudeau, Maureen E; Pritchard, Kathleen; Ghandi, Sonal; Verma, Sunil; Czarnota, Gregory J

2016-07-19

This study demonstrated the ability of quantitative ultrasound (QUS) parameters in providing an early prediction of tumor response to neoadjuvant chemotherapy (NAC) in patients with locally advanced breast cancer (LABC). Using a 6-MHz array transducer, ultrasound radiofrequency (RF) data were collected from 58 LABC patients prior to NAC treatment and at weeks 1, 4, and 8 of their treatment, and prior to surgery. QUS parameters including midband fit (MBF), spectral slope (SS), spectral intercept (SI), spacing among scatterers (SAS), attenuation coefficient estimate (ACE), average scatterer diameter (ASD), and average acoustic concentration (AAC) were determined from the tumor region of interest. Ultrasound data were compared with the ultimate clinical and pathological response of the patient's tumor to treatment and patient recurrence-free survival. Multi-parameter discriminant analysis using the κ-nearest-neighbor classifier demonstrated that the best response classification could be achieved using the combination of MBF, SS, and SAS, with an accuracy of 60 ± 10% at week 1, 77 ± 8% at week 4 and 75 ± 6% at week 8. Furthermore, when the QUS measurements at each time (week) were combined with pre-treatment (week 0) QUS values, the classification accuracies improved (70 ± 9% at week 1, 80 ± 5% at week 4, and 81 ± 6% at week 8). Finally, the multi-parameter QUS model demonstrated a significant difference in survival rates of responding and non-responding patients at weeks 1 and 4 (p=0.035, and 0.027, respectively). This study demonstrated for the first time, using new parameters tested on relatively large patient cohort and leave-one-out classifier evaluation, that a hybrid QUS biomarker including MBF, SS, and SAS could, with relatively high sensitivity and specificity, detect the response of LABC tumors to NAC as early as after 4 weeks of therapy. The findings of this study also suggested that incorporating pre-treatment QUS parameters of a tumor improved the

Quantitative shear-wave optical coherence elastography with a programmable phased array ultrasound as the wave source.

PubMed

Song, Shaozhen; Le, Nhan Minh; Huang, Zhihong; Shen, Tueng; Wang, Ruikang K

2015-11-01

The purpose of this study is to implement a beam-steering ultrasound as the wave source for shear-wave optical coherence elastography (SW-OCE) to achieve an extended range of elastic imaging of the tissue sample. We introduce a linear phased array ultrasound transducer (LPAUT) as the remote and programmable wave source and a phase-sensitive optical coherence tomography (OCT) as the sensitive shear-wave detector. The LPAUT is programmed to launch acoustic radiation force impulses (ARFI) focused at desired locations within the range of OCT imaging, upon which the elasticity map of the entire OCT B-scan cross section is recovered by spatial compounding of the elastic maps derived from each launch of AFRIs. We also propose a directional filter to separate the shear-wave propagation at different directions in order to reduce the effect of tissue heterogeneity on the shear-wave propagation within tissue. The feasibility of this proposed approach is then demonstrated by determining the stiffness of tissue-mimicking phantoms with agarose concentrations of 0.5% and 1% and also by imaging the Young's modulus of retinal and choroidal tissues within a porcine eye ball ex vivo. The approach opens up opportunities to combine medical ultrasound imaging and SW-OCE for high-resolution localized quantitative assessment of tissue biomechanical property.

Challenges and regulatory considerations in the acoustic measurement of high-frequency (>20 MHz) ultrasound.

PubMed

Nagle, Samuel M; Sundar, Guru; Schafer, Mark E; Harris, Gerald R; Vaezy, Shahram; Gessert, James M; Howard, Samuel M; Moore, Mary K; Eaton, Richard M

2013-11-01

This article examines the challenges associated with making acoustic output measurements at high ultrasound frequencies (>20 MHz) in the context of regulatory considerations contained in the US Food and Drug Administration industry guidance document for diagnostic ultrasound devices. Error sources in the acoustic measurement, including hydrophone calibration and spatial averaging, nonlinear distortion, and mechanical alignment, are evaluated, and the limitations of currently available acoustic measurement instruments are discussed. An uncertainty analysis of acoustic intensity and power measurements is presented, and an example uncertainty calculation is done on a hypothetical 30-MHz high-frequency ultrasound system. This analysis concludes that the estimated measurement uncertainty of the acoustic intensity is +73%/-86%, and the uncertainty in the mechanical index is +37%/-43%. These values exceed the respective levels in the Food and Drug Administration guidance document of 30% and 15%, respectively, which are more representative of the measurement uncertainty associated with characterizing lower-frequency ultrasound systems. Recommendations made for minimizing the measurement uncertainty include implementing a mechanical positioning system that has sufficient repeatability and precision, reconstructing the time-pressure waveform via deconvolution using the hydrophone frequency response, and correcting for hydrophone spatial averaging.

Continuous-wave ultrasound reflectometry for surface roughness imaging applications

PubMed Central

Kinnick, R. R.; Greenleaf, J. F.; Fatemi, M.

2009-01-01

Background Measurement of surface roughness irregularities that result from various sources such as manufacturing processes, surface damage, and corrosion, is an important indicator of product quality for many nondestructive testing (NDT) industries. Many techniques exist, however because of their qualitative, time-consuming and direct-contact modes, it is of some importance to work out new experimental methods and efficient tools for quantitative estimation of surface roughness. Objective and Method Here we present continuous-wave ultrasound reflectometry (CWUR) as a novel nondestructive modality for imaging and measuring surface roughness in a non-contact mode. In CWUR, voltage variations due to phase shifts in the reflected ultrasound waves are recorded and processed to form an image of surface roughness. Results An acrylic test block with surface irregularities ranging from 4.22 μm to 19.05 μm as measured by a coordinate measuring machine (CMM), is scanned by an ultrasound transducer having a diameter of 45 mm, a focal distance of 70 mm, and a central frequency of 3 MHz. It is shown that CWUR technique gives very good agreement with the results obtained through CMM inasmuch as the maximum average percent error is around 11.5%. Conclusion Images obtained here demonstrate that CWUR may be used as a powerful noncontact and quantitative tool for nondestructive inspection and imaging of surface irregularities at the micron-size level with an average error of less than 11.5%. PMID:18664399

Prospective Controlled Study of Buttock Fat Transfer Using Ultrasound and Photographic Measurements

PubMed Central

2016-01-01

Background: Buttock fat transfer is now the preferred method for gluteal augmentation. However, its efficacy has not been well-documented using measurements. Methods: Twenty-five consecutive patients underwent buttock fat transfer performed by the author. Twenty-one patients returned for measurements ≥3 months after surgery (inclusion rate, 84%). A separate group of 25 patients undergoing cosmetic surgery without buttock fat transfer served as controls. All patients underwent superwet liposuction using total intravenous anesthesia and no prone positioning. A closed filtration system was used to collect the fat. Subcutaneous fat thickness was assessed using ultrasound imaging. Measurements were made on standardized photographs. The data were controlled for change in body mass index. Clinical data were also evaluated. Results: The mean fat volume injected per buttock was 287 mL (range, 70–550 mL). Ultrasound measurements detected a significant increase in the subcutaneous fat thickness (P ≤ 0.001), with mean increments of 0.66 cm for the right buttock and 0.86 cm for the left buttock and no significant change for control patients. The mean calculated fat retention, based on the measured surface area injected, was 66%. Photographic measurements of buttock projection revealed a significant increase in treated patients (P < 0.01) and no significant change in control patients. There were no clinical complications at either recipient or donor sites and no evidence of oily cysts on ultrasound examinations. Conclusions: Photographic and ultrasound measurements, and clinical findings, confirm that buttock fat transfer effectively and safely increases buttock projection. PMID:27579222

Influence of anthropometric parameters on ultrasound measurements of Os calcis.

PubMed

Hans, D; Schott, A M; Arlot, M E; Sornay, E; Delmas, P D; Meunier, P J

1995-01-01

Few data have been published concerning the influence of height, weight and body mass index (BMI) on broadband ultrasound attenuation (BUA), speed of sound (SOS) and Lunar "stiffness" index, and always in small population samples. The first ain of the present cross-sectional study was to determine whether anthropometric factors have a significant influence on ultrasound measurements. The second objective was to establish whether these parameters have real effect on whether their influence is due only to measurement errors. We measured, in 271 healthy French women (mean age 77 +/- 11 years; range 31-97 years), the following parameters: age, height, weight, lean and fat body mass, heel width, foot length, knee height and external malleolus (HEM). Simple linear regression analyses between ultrasound and anthropometric parameters were performed. Age, height, and heel width were significant predictors of SOS; age, height, weight, foot length, heel width, HEM, fat mass and lean mass were significant predictors of BUA; age, height, weight, heel width, HEM, fat mass and lean mass were significant predictors of stiffness. In the multiple regression analysis, once the analysis had been adjusted for age, only heel width was a significant predictor for SOS (p = 0.0007), weight for BUA (p = 0.0001), and weight (p = 0.0001) and heel width (p = 0.004) for the stiffness index. Besides their statistical meaning, the regression coefficients have a more clinically relevant interpretation which is developed in the text. These results confirm the influence of anthropometric factors on the ultrasonic parameter values, because BUA and SOS were in part dependent on heel width and weight. The influence of the position of the transducer on the calcaneus should be taken into account to optimize the methods of measurement using ultrasound.

An automated in vitro model for the evaluation of ultrasound modalities measuring myocardial deformation

PubMed Central

2010-01-01

Background Echocardiography is the method of choice when one wishes to examine myocardial function. Qualitative assessment of the 2D grey scale images obtained is subjective, and objective methods are required. Speckle Tracking Ultrasound is an emerging technology, offering an objective mean of quantifying left ventricular wall motion. However, before a new ultrasound technology can be adopted in the clinic, accuracy and reproducibility needs to be investigated. Aim It was hypothesized that the collection of ultrasound sample data from an in vitro model could be automated. The aim was to optimize an in vitro model to allow for efficient collection of sample data. Material & Methods A tissue-mimicking phantom was made from water, gelatin powder, psyllium fibers and a preservative. Sonomicrometry crystals were molded into the phantom. The solid phantom was mounted in a stable stand and cyclically compressed. Peak strain was then measured by Speckle Tracking Ultrasound and sonomicrometry. Results We succeeded in automating the acquisition and analysis of sample data. Sample data was collected at a rate of 200 measurement pairs in 30 minutes. We found good agreement between Speckle Tracking Ultrasound and sonomicrometry in the in vitro model. Best agreement was 0.83 ± 0.70%. Worst agreement was -1.13 ± 6.46%. Conclusions It has been shown possible to automate a model that can be used for evaluating the in vitro accuracy and precision of ultrasound modalities measuring deformation. Sonomicrometry and Speckle Tracking Ultrasound had acceptable agreement. PMID:20822532

Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network.

PubMed

Xing, Jida; Chen, Jie

2015-06-23

In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

Design of a Thermoacoustic Sensor for Low Intensity Ultrasound Measurements Based on an Artificial Neural Network

PubMed Central

Xing, Jida; Chen, Jie

2015-01-01

In therapeutic ultrasound applications, accurate ultrasound output intensities are crucial because the physiological effects of therapeutic ultrasound are very sensitive to the intensity and duration of these applications. Although radiation force balance is a benchmark technique for measuring ultrasound intensity and power, it is costly, difficult to operate, and compromised by noise vibration. To overcome these limitations, the development of a low-cost, easy to operate, and vibration-resistant alternative device is necessary for rapid ultrasound intensity measurement. Therefore, we proposed and validated a novel two-layer thermoacoustic sensor using an artificial neural network technique to accurately measure low ultrasound intensities between 30 and 120 mW/cm2. The first layer of the sensor design is a cylindrical absorber made of plexiglass, followed by a second layer composed of polyurethane rubber with a high attenuation coefficient to absorb extra ultrasound energy. The sensor determined ultrasound intensities according to a temperature elevation induced by heat converted from incident acoustic energy. Compared with our previous one-layer sensor design, the new two-layer sensor enhanced the ultrasound absorption efficiency to provide more rapid and reliable measurements. Using a three-dimensional model in the K-wave toolbox, our simulation of the ultrasound propagation process demonstrated that the two-layer design is more efficient than the single layer design. We also integrated an artificial neural network algorithm to compensate for the large measurement offset. After obtaining multiple parameters of the sensor characteristics through calibration, the artificial neural network is built to correct temperature drifts and increase the reliability of our thermoacoustic measurements through iterative training about ten seconds. The performance of the artificial neural network method was validated through a series of experiments. Compared to our previous

Measurement and numerical simulation of high intensity focused ultrasound field in water

NASA Astrophysics Data System (ADS)

Lee, Kang Il

2017-11-01

In the present study, the acoustic field of a high intensity focused ultrasound (HIFU) transducer in water was measured by using a commercially available needle hydrophone intended for HIFU use. To validate the results of hydrophone measurements, numerical simulations of HIFU fields were performed by integrating the axisymmetric Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation from the frequency-domain perspective with the help of a MATLAB-based software package developed for HIFU simulation. Quantitative values for the focal waveforms, the peak pressures, and the size of the focal spot were obtained in various regimes of linear, quasilinear, and nonlinear propagation up to the source pressure levels when the shock front was formed in the waveform. The numerical results with the HIFU simulator solving the KZK equation were compared with the experimental data and found to be in good agreement. This confirms that the numerical simulation based on the KZK equation is capable of capturing the nonlinear pressure field of therapeutic HIFU transducers well enough to make it suitable for HIFU treatment planning.

Localization of the transverse processes in ultrasound for spinal curvature measurement

NASA Astrophysics Data System (ADS)

Kamali, Shahrokh; Ungi, Tamas; Lasso, Andras; Yan, Christina; Lougheed, Matthew; Fichtinger, Gabor

2017-03-01

PURPOSE: In scoliosis monitoring, tracked ultrasound has been explored as a safer imaging alternative to traditional radiography. The use of ultrasound in spinal curvature measurement requires identification of vertebral landmarks such as transverse processes, but as bones have reduced visibility in ultrasound imaging, skeletal landmarks are typically segmented manually, which is an exceedingly laborious and long process. We propose an automatic algorithm to segment and localize the surface of bony areas in the transverse process for scoliosis in ultrasound. METHODS: The algorithm uses cascade of filters to remove low intensity pixels, smooth the image and detect bony edges. By applying first differentiation, candidate bony areas are classified. The average intensity under each area has a correlation with the possibility of a shadow, and areas with strong shadow are kept for bone segmentation. The segmented images are used to reconstruct a 3-D volume to represent the whole spinal structure around the transverse processes. RESULTS: A comparison between the manual ground truth segmentation and the automatic algorithm in 50 images showed 0.17 mm average difference. The time to process all 1,938 images was about 37 Sec. (0.0191 Sec. / Image), including reading the original sequence file. CONCLUSION: Initial experiments showed the algorithm to be sufficiently accurate and fast for segmentation transverse processes in ultrasound for spinal curvature measurement. An extensive evaluation of the method is currently underway on images from a larger patient cohort and using multiple observers in producing ground truth segmentation.

Ultrasound Applied to Subcutaneous Fat Tissue Measurements in International Elite Canoeists.

PubMed

Kopinski, S; Engel, T; Cassel, M; Fröhlich, K; Mayer, F; Carlsohn, A

2015-12-01

Subcutaneous adipose tissue (SAT) measurements with ultrasound have recently been introduced to assess body fat in elite athletes. However, appropriate protocols and data on various groups of athletes are missing. We investigated intra-rater reliability of SAT measurements using ultrasound in elite canoe athletes. 25 international level canoeists (18 male, 7 female; 23±4 years; 81±11 kg; 1.83±0.09 m; 20±3 training h/wk) were measured on 2 consecutive days. SAT was assessed with B-mode ultrasound at 8 sites (ISAK): triceps, subscapular, biceps, iliac crest, supraspinal, abdominal, front thigh, medial calf, and quantified using image analysis software. Data was analyzed descriptively (mean±SD, [range]). Coefficient of variation (CV%), intraclass correlation coefficient (ICC, 2.1) and absolute (LoA) and ratio limits of agreement (RLoA) were calculated for day-to-day reliability. Mean sum of SAT thickness was 30.0±19.4 mm [8.0, 80.1 mm], with 3.9±1.8 mm [1.2 mm subscapular, 8.0 mm abdominal] for individual sites. CV for the sum of sites was 4.7%, ICC 0.99, LoA 1.7±3.6 mm, RLoA 0.940 ( *  /÷1.155). Measuring SAT with ultrasound has proved to have excellent day-to-day reliability in elite canoe athletes. Recommendations for standardization of the method will further increase accuracy and reproducibility. © Georg Thieme Verlag KG Stuttgart · New York.

A priori Prediction of Neoadjuvant Chemotherapy Response and Survival in Breast Cancer Patients using Quantitative Ultrasound

PubMed Central

Tadayyon, Hadi; Sannachi, Lakshmanan; Gangeh, Mehrdad J.; Kim, Christina; Ghandi, Sonal; Trudeau, Maureen; Pritchard, Kathleen; Tran, William T.; Slodkowska, Elzbieta; Sadeghi-Naini, Ali; Czarnota, Gregory J.

2017-01-01

Quantitative ultrasound (QUS) can probe tissue structure and analyze tumour characteristics. Using a 6-MHz ultrasound system, radiofrequency data were acquired from 56 locally advanced breast cancer patients prior to their neoadjuvant chemotherapy (NAC) and QUS texture features were computed from regions of interest in tumour cores and their margins as potential predictive and prognostic indicators. Breast tumour molecular features were also collected and used for analysis. A multiparametric QUS model was constructed, which demonstrated a response prediction accuracy of 88% and ability to predict patient 5-year survival rates (p = 0.01). QUS features demonstrated superior performance in comparison to molecular markers and the combination of QUS and molecular markers did not improve response prediction. This study demonstrates, for the first time, that non-invasive QUS features in the core and margin of breast tumours can indicate breast cancer response to neoadjuvant chemotherapy (NAC) and predict five-year recurrence-free survival. PMID:28401902

A priori Prediction of Neoadjuvant Chemotherapy Response and Survival in Breast Cancer Patients using Quantitative Ultrasound.

PubMed

Tadayyon, Hadi; Sannachi, Lakshmanan; Gangeh, Mehrdad J; Kim, Christina; Ghandi, Sonal; Trudeau, Maureen; Pritchard, Kathleen; Tran, William T; Slodkowska, Elzbieta; Sadeghi-Naini, Ali; Czarnota, Gregory J

2017-04-12

Quantitative ultrasound (QUS) can probe tissue structure and analyze tumour characteristics. Using a 6-MHz ultrasound system, radiofrequency data were acquired from 56 locally advanced breast cancer patients prior to their neoadjuvant chemotherapy (NAC) and QUS texture features were computed from regions of interest in tumour cores and their margins as potential predictive and prognostic indicators. Breast tumour molecular features were also collected and used for analysis. A multiparametric QUS model was constructed, which demonstrated a response prediction accuracy of 88% and ability to predict patient 5-year survival rates (p = 0.01). QUS features demonstrated superior performance in comparison to molecular markers and the combination of QUS and molecular markers did not improve response prediction. This study demonstrates, for the first time, that non-invasive QUS features in the core and margin of breast tumours can indicate breast cancer response to neoadjuvant chemotherapy (NAC) and predict five-year recurrence-free survival.

Development of Ultrasound to Measure In-vivo Dynamic Cervical Spine Intervertebral Disc Mechanics

DTIC Science & Technology

2015-01-01

1 AD_________ Award Number: W81XWH-13-1-0050 TITLE: Development of Ultrasound to Measure In-vivo Dynamic Cervical Spine Intervertebral Disc...COVERED 27 Dec 2013 - 26 Dec 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Development of Ultrasound to Measure In-vivo Dynamic Cervical Spine...Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Neck pain is pervasive problems in military population

Ultrasound measures of tendon thickness: Intra-rater, Inter-rater and Inter-machine reliability.

PubMed

Del Baño-Aledo, María Elena; Martínez-Payá, Jacinto Javier; Ríos-Díaz, José; Mejías-Suárez, Silvia; Serrano-Carmona, Sergio; de Groot-Ferrando, Ana

2017-01-01

Ultrasound imaging is often used by physiotherapists and other healthcare professionals but the reliability of image acquisition with different ultrasound machines is unknown. The objective was to compare the intra-rater, inter-rater and intermachine reliability of thickness measurements of the plantar fascia (PF), Achilles tendon (AT), patellar tendon (PT) and elbow common extensor tendon (ECET) with musculoskeletal ultrasound imaging (MSUS). Tendon thickness was measured in four anatomical structures (14 participants, 28 images per tendon) by two sonographers and with two different ultrasound machines. Intraclass Correlation Coefficients (ICCs) and Bland-Altman plots were calculated. The standard error of measurement (SEM) and minimum detectable difference (MDD) were calculated. Inter-rater reliability was excellent for AT (ICC=0.98; 95% CI= 0.96-0.99) and very good for PT (ICC=0.85; 95% CI = 0.67-0.93) and ECET (ICC=0.81; 95% CI= 0.72-0.94). Reliability for PF was moderate, with an ICC of 0.63 (CI 95%= 0.20-0.83). Bland-Altman plot for inter-machine reliability showed a mean difference of 1 m for PF measurements and a mean difference of 4 m and 20 m for AT and PT. The relative SEMs were below 7% and the MDCs were below 0.7 mm. The MSUS reliability in measuring thickness of the four tendons is confirmed by the homogeneous readings intra sonographers, between operators and between different machines. Level of evidence: Tendon thickness can be measured reliably on different ultrasound devices, which is an important step forward in the use of this technique in daily clinical practice and research. III.

Ultrasound measurement of transcranial distance during head-down tilt

NASA Technical Reports Server (NTRS)

Torikoshi, S.; Wilson, M. H.; Ballard, R. E.; Watenpaugh, D. E.; Murthy, G.; Yost, W. T.; Cantrell, J. H.; Chang, D. S.; Hargens, A. R.

1995-01-01

Exposure to microgravity elevates blood pressure and flow in the head, which may increase intracranial volume (ICV) and intracranial pressure (ICP). Rhesus monkeys exposed to simulated microgravity in the form of 6 degree head-down tilt (HDT) experience elevated ICP. With humans, twenty-four hours of 6 degree HDT bed rest increases cerebral blood flow velocity relative to pre-HDT upright posture. Humans exposed to acute 6 degree HDT experiments increased ICP, measured with the tympanic membrane displacement (TMD) technique. Other studies suggest that increased ICP in humans and cats causes measurable cranial bone movement across the sagittal suture. Due to the slightly compliant nature of the cranium, elevation of the ICP will increase ICV and transcranial distance. Currently, several non-invasive approaches to monitor ICP are being investigated. Such techniques include TMD and modal analysis of the skull. TMD may not be reliable over a large range of ICP and neither method is capable of measuring the small changes in pressure. Ultrasound, however, may reliably measure small distance changes that accompany ICP fluctuations. The purpose of our study was to develop and evaluate an ultrasound technique to measure transcranial distance changes during HDT.

Demonstration of movement in the sacroiliac joint using ultrasound

NASA Astrophysics Data System (ADS)

Krupinski, Elizabeth A.; Brooks, William J.; Lund, Pamela J.

1995-05-01

The goal of this study was to demonstrate quantitatively, using ultrasound (US) recording techniques, the extent of motion of the sacroiliac joint achieved using manual medicine techniques. Initial judgements of perceived (i.e., felt) SI mobility during manual examination were made on 22 subjects. Baseline no movement ultrasound images (static) were obtained of the left and right SI joints at two levels-- posterior-superior-iliac-spine and inferior (PSIS, INF)--and two projections (AP and LAT). Manual medicine spring testing of the SI joint was then performed while ultrasound recordings (on video) were made. The differences between baseline separation of the SI joint and displacement distance during spring testing were measured by six radiologists who typically read US images. Significant movement of at least one SI joint was demonstrated in 91% of the subjects using ultrasound recordings. The extent of movement appeared to corroborate the experience of manual medicine practitioners.

Response monitoring using quantitative ultrasound methods and supervised dictionary learning in locally advanced breast cancer

NASA Astrophysics Data System (ADS)

Gangeh, Mehrdad J.; Fung, Brandon; Tadayyon, Hadi; Tran, William T.; Czarnota, Gregory J.

2016-03-01

A non-invasive computer-aided-theragnosis (CAT) system was developed for the early assessment of responses to neoadjuvant chemotherapy in patients with locally advanced breast cancer. The CAT system was based on quantitative ultrasound spectroscopy methods comprising several modules including feature extraction, a metric to measure the dissimilarity between "pre-" and "mid-treatment" scans, and a supervised learning algorithm for the classification of patients to responders/non-responders. One major requirement for the successful design of a high-performance CAT system is to accurately measure the changes in parametric maps before treatment onset and during the course of treatment. To this end, a unified framework based on Hilbert-Schmidt independence criterion (HSIC) was used for the design of feature extraction from parametric maps and the dissimilarity measure between the "pre-" and "mid-treatment" scans. For the feature extraction, HSIC was used to design a supervised dictionary learning (SDL) method by maximizing the dependency between the scans taken from "pre-" and "mid-treatment" with "dummy labels" given to the scans. For the dissimilarity measure, an HSIC-based metric was employed to effectively measure the changes in parametric maps as an indication of treatment effectiveness. The HSIC-based feature extraction and dissimilarity measure used a kernel function to nonlinearly transform input vectors into a higher dimensional feature space and computed the population means in the new space, where enhanced group separability was ideally obtained. The results of the classification using the developed CAT system indicated an improvement of performance compared to a CAT system with basic features using histogram of intensity.

Factors Associated with Bone Health in Malaysian Middle-Aged and Elderly Women Assessed via Quantitative Ultrasound.

PubMed

Chin, Kok-Yong; Low, Nie Yen; Dewiputri, Wan Ilma; Ima-Nirwanaa, Soelaiman

2017-07-06

Risk factors for osteoporosis may vary according to different populations. We aimed to investigate the relationship between risk factors of osteoporosis and bone health indices determined via calcaneal quantitative ultrasound (QUS) in a group of Malaysian women aged 50 years or above. A cross-sectional study was performed on 344 Malaysian women recruited from a tertiary medical centre in Kuala Lumpur, Malaysia. They answered a self-administered questionnaire on their social-demographic details, medical history, lifestyle, and physical activity status. Their height was measured using a stadiometer, and their body composition estimated using a bioelectrical impedance device. Their bone health status was determined using a water-based calcaneal QUS device that generated three indices, namely speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index (SI). A T-score was computed from SI values using a reference database from a mainland Chinese population. Women with three or more lifetime pregnancies, who were underweight and not drinking coffee had a significantly lower BUA. Stepwise multiple linear regression showed that SOS was predicted by age alone, BUA and SI by years since menopause, body mass index (BMI), and number of lifetime pregnancies, and T-score by years since menopause and percentage of body fat. As a conclusion, suboptimal bone health in middle-aged and elderly Malaysian women as indicated by QUS is associated with old age, being underweight, having a high body fat percentage, and a high number of lifetime pregnancies. Women having several risk factors should be monitored more closely to protect their bones against accelerated bone loss.

Advanced ultrasound applications in the assessment of renal transplants: contrast-enhanced ultrasound, elastography, and B-flow.

PubMed

Morgan, Tara A; Jha, Priyanka; Poder, Liina; Weinstein, Stefanie

2018-04-09

Ultrasound is routinely used as the first imaging exam for evaluation of renal transplants and can identify most major surgical complications and evaluate vascularity with color Doppler. Ultrasound is limited, however, in the detection of parenchymal disease processes and Doppler evaluation is also prone to technical errors. Multiple new ultrasound applications have been developed and are under ongoing investigation which could add additional diagnostic capability to the routine ultrasound exam with minimal additional time, cost, and patient risk. Contrast-enhanced ultrasound (CEUS) can be used off-label in the transplant kidney, and can assist in detection of infection, trauma, and vascular complications. CEUS also can demonstrate perfusion of the transplant assessed quantitatively with generation of time-intensity curves. Future directions of CEUS include monitoring treatment response and microbubble targeted medication delivery. Elastography is an ultrasound application that can detect changes in tissue elasticity, which is useful to diagnose diffuse parenchymal disease, such as fibrosis, otherwise unrecognizable with ultrasound. Elastography has been successfully applied in other organs including the liver, thyroid, and breast; however, it is still under development for use in the transplant kidney. Unique properties of the transplant kidney including its heterogeneity, anatomic location, and other technical factors present challenges in the development of reference standard measurements. Lastly, B-flow imaging is a flow application derived from B-mode. This application can show the true lumen size of a vessel which is useful to depict vascular anatomy and bypasses some of the pitfalls of color Doppler such as demonstration of slow flow.

Mechanotransduction of Ultrasound is Frequency Dependent Below the Cavitation Threshold

PubMed Central

Louw, Tobias M.; Budhiraja, Gaurav; Viljoen, Hendrik J.; Subramanian, Anuradha

2013-01-01

This study provides evidence that low-intensity ultrasound directly affects nuclear processes, and the magnitude of the effect varies with frequency. In particular, we show that the transcriptional induction of first load-inducible genes, which is independent of new protein synthesis, is frequency dependent. Bovine chondrocytes were exposed to low-intensity below the cavitational threshold) ultrasound at 2,5 and 8 MHz. Ultrasound elevated the expression of early response genes c-Fos, c-Jun and c-Myc, maximized at 5 MHz. The phosphorylated ERK inhibitor PD98059 abrogated any increase in c-series gene expression, suggesting that signaling occurs via the MAPPK/ERK pathway. However, phosphorylated ERK levels did not change with ultrasound frequency, indicating that processes downstream of ERK phosphorylation (such as nuclear transport and chromatin reorganization) respond to ultrasound with frequency dependence. A quantitative, biphasic mathematical model based on Biot theory predicted that cytoplasmic and nuclear stress is maximized at 5.2 ± 0.8 MHz for a chondrocyte, confirming experimental measurements. PMID:23562015

Comparison of translabial three-dimensional ultrasound with magnetic resonance imaging for measurement of levator hiatal biometry at rest.

PubMed

Vergeldt, T F M; Notten, K J B; Stoker, J; Fütterer, J J; Beets-Tan, R G; Vliegen, R F A; Schweitzer, K J; Mulder, F E M; van Kuijk, S M J; Roovers, J P W R; Kluivers, K B; Weemhoff, M

2016-05-01

To compare translabial three-dimensional (3D) ultrasound with magnetic resonance imaging (MRI) for the measurement of levator hiatal biometry at rest in women with pelvic organ prolapse, and to determine the interobserver reliability between two independent observers for ultrasound and MRI measurements. Data were derived from a multicenter prospective cohort study in which women scheduled for conventional anterior colporrhaphy underwent translabial 3D ultrasound and MRI prior to surgery. Intraclass correlation coefficients (ICCs) were calculated to estimate interobserver reliability between two independent observers and determine the agreement between ultrasound and MRI measurements. Bland-Altman plots were created to assess the agreement between ultrasound and MRI measurements. Data from 139 women from nine hospitals were included in the study. The interobserver reliability of ultrasound assessment at rest, during Valsalva maneuver and during contraction and of MRI assessment at rest were moderate or good. The agreement between ultrasound and MRI for the measurement of levator hiatal biometry at rest was moderate, with ICCs of 0.52 (95%CI, 0.32-0.66) for levator hiatal area, 0.44 (95%CI, 0.21-0.60) for anteroposterior diameter and 0.44 (95%CI, 0.22-0.60) for transverse diameter. Levator hiatal biometry measurements were statistically significantly larger on MRI than on translabial 3D ultrasound. The agreement between translabial 3D ultrasound and MRI for measurement of the levator hiatus at rest in women with pelvic organ prolapse was only moderate. The results of translabial 3D ultrasound and MRI should therefore not be used interchangeably in daily practice or in clinical research. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Contrast-enhanced ultrasound for quantitative assessment of portal pressure in canine liver fibrosis.

PubMed

Zhai, Lin; Qiu, Lan-Yan; Zu, Yuan; Yan, Yan; Ren, Xiao-Zhuan; Zhao, Jun-Feng; Liu, Yu-Jiang; Liu, Ji-Bin; Qian, Lin-Xue

2015-04-21

To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound (CEUS) in a canine model. Liver fibrosis was established in adult canines (Beagles; n = 14) by subcutaneous injection of carbon tetrachloride (CCl4). CEUS parameters, including the area under the time-intensity curve and intensity at portal/arterial phases (Qp/Qa and Ip/Ia, respectively), were used to quantitatively assess the blood flow ratio of the portal vein/hepatic artery at multiple time points. The free portal venous pressures (FPP) were measured by a multi-channel baroreceptor using a percutaneous approach at baseline and 8, 16, and 24 wk after CCl4 injections in each canine. Liver biopsies were obtained at the end of 8, 16, and 24 wk from each animal, and the stage of the fibrosis was assessed according to the Metavir scoring system. A Pearson correlation test was performed to compare the FPP with Qp/Qa and Ip/Ia. Pathologic examination of 42 biopsies from the 14 canines at weeks 8, 16, and 24 revealed that liver fibrosis was induced by CCl4 and represented various stages of liver fibrosis, including F0 (n = 3), F1 (n = 12), F2 (n = 14), F3 (n = 11), and F4 (n = 2). There were significant differences in the measurements of Qp/Qa (19.85 ± 3.30 vs 10.43 ± 1.21, 9.63 ± 1.03, and 8.77 ± 0.96) and Ip/Ia (1.77 ± 0.37 vs 1.03 ± 0.12, 0.83 ± 0.10, and 0.69 ± 0.13) between control and canine fibrosis at 8, 16, and 24 wk, respectively (all P < 0.001). There were statistically significant negative correlations between FPP and Qp/Qa (r = -0.707, P < 0.001), and between FPP and Ip/Ia (r = -0.759, P < 0.001) in the canine fibrosis model. Prediction of elevated FPP based on Qp/Qa and Ip/Ia was highly sensitive, as assessed by the area under the receiver operating curve (0.866 and 0.895, respectively). CEUS is a potential method to accurately, but non-invasively, estimate portal venous pressure through measurement of Qp/Qa and Ip

Ultrasound Imaging Techniques for Spatiotemporal Characterization of Composition, Microstructure, and Mechanical Properties in Tissue Engineering.

PubMed

Deng, Cheri X; Hong, Xiaowei; Stegemann, Jan P

2016-08-01

Ultrasound techniques are increasingly being used to quantitatively characterize both native and engineered tissues. This review provides an overview and selected examples of the main techniques used in these applications. Grayscale imaging has been used to characterize extracellular matrix deposition, and quantitative ultrasound imaging based on the integrated backscatter coefficient has been applied to estimating cell concentrations and matrix morphology in tissue engineering. Spectral analysis has been employed to characterize the concentration and spatial distribution of mineral particles in a construct, as well as to monitor mineral deposition by cells over time. Ultrasound techniques have also been used to measure the mechanical properties of native and engineered tissues. Conventional ultrasound elasticity imaging and acoustic radiation force imaging have been applied to detect regions of altered stiffness within tissues. Sonorheometry and monitoring of steady-state excitation and recovery have been used to characterize viscoelastic properties of tissue using a single transducer to both deform and image the sample. Dual-mode ultrasound elastography uses separate ultrasound transducers to produce a more potent deformation force to microscale characterization of viscoelasticity of hydrogel constructs. These ultrasound-based techniques have high potential to impact the field of tissue engineering as they are further developed and their range of applications expands.

Quantitative Assessment of Skin Stiffness in Localized Scleroderma Using Ultrasound Shear-Wave Elastography.

PubMed

Wang, Liyun; Yan, Feng; Yang, Yujia; Xiang, Xi; Qiu, Li

2017-07-01

The purpose of this study was to evaluate the usefulness of ultrasound shear-wave elastography (US-SWE) in characterization of localized scleroderma (LS), as well as in the disease staging. A total of 21 patients with 37 LS lesions were enrolled in this study. The pathologic stage (edema, sclerosis or atrophy) of the lesions was characterized by pathologic examination. The skin elastic modulus (E-values including E mean , E min , E max and E sd ) and thickness (h) was evaluated both in LS lesions and site-matched unaffected skin (normal controls) using US-SWE. The relative difference of E-values (E RD ) was calculated between each pair of lesions and its normal control for comparison among different pathologic stages. Of the 37 LS lesions, 2 were in edema, 22 were in sclerosis and 13 were in atrophy. US-SWE results showed a significant increase of skin elastic modulus and thickness in all lesions (p < 0.001 in sclerosis and p < 0.05 in atrophy) compared with the normal controls. The measured skin elastic modulus and thickness were greater in sclerosis than in atrophy. However, once normalized by skin thickness, the atrophic lesions, which were on average thinner, appeared significantly stiffer than those of the sclerosis (normalized E RD : an increase of 316.3% in atrophy vs. 50.6% in sclerosis compared with the controls, p = 0.007). These findings suggest that US-SWE allows for quantitative evaluation of the skin stiffness of LS lesions in different stages; however, the E-values directly provided by the US-SWE system alone do not distinguish between the stages, and the normalization by skin thickness is necessary. This non-invasive, real-time imaging technique is an ideal tool for assessing and monitoring LS disease severity and progression. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Accuracy of computed tomographic angiography for stenosis quantification using quantitative coronary angiography or intravascular ultrasound as the gold standard.

PubMed

Joshi, Subodh B; Okabe, Teruo; Roswell, Robert O; Weissman, Gaby; Lopez, Cristian F; Lindsay, Joseph; Pichard, Augusto D; Weissman, Neil J; Waksman, Ron; Weigold, Wm Guy

2009-10-15

Computed tomographic angiography (CTA) is considered to have limited accuracy for quantifying exact percent diameter stenosis in coronary arteries. However, most studies evaluating CTA use quantitative coronary angiography (QCA) as the gold standard, a technique with its own limitations. We sought to determine whether CTA measurements of stenosis severity correlate better with intravascular ultrasound (IVUS) than with QCA. Luminal dimensions of 67 de novo coronary lesions were measured by CTA, IVUS, and QCA. IVUS was performed when lesion severity by angiography was equivocal. Mean percent diameter stenosis by QCA was 51 +/- 9.8% and mean IVUS minimal luminal area was 3.8 +/- 1.8 mm(2). There was a moderate correlation between CTA minimal luminal area and IVUS minimal luminal area (r(2) = 0.41, p <0.001), but no relation between CTA and QCA measurements of minimal luminal diameter (r(2) = 0.01, p = 0.57) or diameter stenosis (r(2) = 0.02, p = 0.31). There was also no relation between IVUS minimal luminal area and QCA diameter stenosis (r(2) = 0.01, p = 0.50). When lesions with moderate or severe calcification were excluded, the correlation between CTA minimal luminal area and IVUS minimal luminal area was good (r(2) = 0.68, p <0.001). In conclusion, in this cohort of patients with intermediate-grade lesions on cardiac catheterization, absolute measurements of stenosis severity on CTA correlated with IVUS but not with QCA. Our findings suggest that limitations of quantitative coronary angiography as a gold standard need to be considered in studies evaluating the accuracy of coronary CTA.

Ultrasound arthroscopy of human knee cartilage and subchondral bone in vivo.

PubMed

Liukkonen, Jukka; Lehenkari, Petri; Hirvasniemi, Jukka; Joukainen, Antti; Virén, Tuomas; Saarakkala, Simo; Nieminen, Miika T; Jurvelin, Jukka S; Töyräs, Juha

2014-09-01

Arthroscopic ultrasound imaging enables quantitative evaluation of articular cartilage. However, the potential of this technique for evaluation of subchondral bone has not been investigated in vivo. In this study, we address this issue in clinical arthroscopy of the human knee (n = 11) by determining quantitative ultrasound (9 MHz) reflection and backscattering parameters for cartilage and subchondral bone. Furthermore, in each knee, seven anatomical sites were graded using the International Cartilage Repair Society (ICRS) system based on (i) conventional arthroscopy and (ii) ultrasound images acquired in arthroscopy with a miniature transducer. Ultrasound enabled visualization of articular cartilage and subchondral bone. ICRS grades based on ultrasound images were higher (p < 0.05) than those based on conventional arthroscopy. The higher ultrasound-based ICRS grades were expected as ultrasound reveals additional information on, for example, the relative depth of the lesion. In line with previous literature, ultrasound reflection and scattering in cartilage varied significantly (p < 0.05) along the ICRS scale. However, no significant correlation between ultrasound parameters and structure or density of subchondral bone could be demonstrated. To conclude, arthroscopic ultrasound imaging had a significant effect on clinical grading of cartilage, and it was found to provide quantitative information on cartilage. The lack of correlation between the ultrasound parameters and bone properties may be related to lesser bone change or excessive attenuation in overlying cartilage and insufficient power of the applied miniature transducer. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Modifiable lifestyle factors affecting bone health using calcaneus quantitative ultrasound in adolescent girls.

PubMed

Robinson, M L; Winters-Stone, K; Gabel, K; Dolny, D

2007-08-01

One hundred and fourteen girls were measured for calcaneus QUS (stiffness index score), calcium intake, weight, and total hours spent in physical activity (moderate to high-impact activities and low to no-impact activities). Multiple regression analysis indicated that hours spent in moderate to high-impact activities, current calcium intake, and weight significantly predicted SI. To determine the influence of modifiable lifestyle factors on adolescent girls' bone health measured by calcaneus quantitative ultrasound (QUS). One hundred and fourteen girls, ages 14-18 (15.97 +/- .7), enrolled in high school physical education classes, were measured for calcaneus QUS (stiffness index score), height, weight, current calcium intake from 2-3 day food records, and estimated total hours spent in physical activity from kindergarten to present. Cumulative physical activity hours were separated into two classifications (according to their estimated strain from ground reaction force): moderate to high-impact activities and low to no-impact activities. Pearson correlations between stiffness index (SI) and age, height, weight, current calcium intake, and hours spent in moderate to high-impact versus low to no-impact activities indicated a positive relationships between SI and weight (r = .259, p = .005), current calcium intake (r = .286, p = .002), and hours spent in moderate to high-impact activities (r = .451, p < .001). Multiple regression between SI and the above independent variables indicated that collectively, hours spent in moderate to high-impact activities, current calcium intake, and weight (r (2) = .363, p = <.001) significantly predicted SI. Our data indicate that moderate to high-impact activities, current calcium intake, and weight positively influence bone properties of the calcaneus in adolescent girls.

Validity of measurement of shear modulus by ultrasound shear wave elastography in human pennate muscle.

PubMed

Miyamoto, Naokazu; Hirata, Kosuke; Kanehisa, Hiroaki; Yoshitake, Yasuhide

2015-01-01

Ultrasound shear wave elastography is becoming a valuable tool for measuring mechanical properties of individual muscles. Since ultrasound shear wave elastography measures shear modulus along the principal axis of the probe (i.e., along the transverse axis of the imaging plane), the measured shear modulus most accurately represents the mechanical property of the muscle along the fascicle direction when the probe's principal axis is parallel to the fascicle direction in the plane of the ultrasound image. However, it is unclear how the measured shear modulus is affected by the probe angle relative to the fascicle direction in the same plane. The purpose of the present study was therefore to examine whether the angle between the principal axis of the probe and the fascicle direction in the same plane affects the measured shear modulus. Shear modulus in seven specially-designed tissue-mimicking phantoms, and in eleven human in-vivo biceps brachii and medial gastrocnemius were determined by using ultrasound shear wave elastography. The probe was positioned parallel or 20° obliquely to the fascicle across the B-mode images. The reproducibility of shear modulus measurements was high for both parallel and oblique conditions. Although there was a significant effect of the probe angle relative to the fascicle on the shear modulus in human experiment, the magnitude was negligibly small. These findings indicate that the ultrasound shear wave elastography is a valid tool for evaluating the mechanical property of pennate muscles along the fascicle direction.

Ultrasound Elastography: Review of Techniques and Clinical Applications

PubMed Central

Sigrist, Rosa M.S.; Liau, Joy; Kaffas, Ahmed El; Chammas, Maria Cristina; Willmann, Juergen K.

2017-01-01

Elastography-based imaging techniques have received substantial attention in recent years for non-invasive assessment of tissue mechanical properties. These techniques take advantage of changed soft tissue elasticity in various pathologies to yield qualitative and quantitative information that can be used for diagnostic purposes. Measurements are acquired in specialized imaging modes that can detect tissue stiffness in response to an applied mechanical force (compression or shear wave). Ultrasound-based methods are of particular interest due to its many inherent advantages, such as wide availability including at the bedside and relatively low cost. Several ultrasound elastography techniques using different excitation methods have been developed. In general, these can be classified into strain imaging methods that use internal or external compression stimuli, and shear wave imaging that use ultrasound-generated traveling shear wave stimuli. While ultrasound elastography has shown promising results for non-invasive assessment of liver fibrosis, new applications in breast, thyroid, prostate, kidney and lymph node imaging are emerging. Here, we review the basic principles, foundation physics, and limitations of ultrasound elastography and summarize its current clinical use and ongoing developments in various clinical applications. PMID:28435467

HOCUS: The Haskins optically-corrected ultrasound system for measuring speech articulation

NASA Astrophysics Data System (ADS)

Whalen, D. H.; Iskarous, Khalil; Tiede, Mark K.; Ostry, David J.

2004-05-01

The tongue is the most important supralaryngeal articulator for speech, yet, because it is typically out of view, its movements have been difficult to quantify. Here is described a new combination of techniques involving ultrasound in conjunction with an optoelectric motion measurement system (Optotrak). Combining these, the movements of the tongue are imaged and simultaneously corrected for motion of the head and of the ultrasound transceiver. Optotrak's infrared-emitting diodes are placed on the transceiver and the speakers head in order to localize the ultrasound image of the tongue relative to the hard palate. The palate can be imaged with ultrasound by having the ultrasound signal penetrate a water bolus held against the palate by the tongue. This trace is coregistered with the head and potentially with the same talker's sagittal MR image, to provide additional information on the unimaged remainder of the tract. The tongue surface, from the larynx to near the tip, can then be localized in relationship to the hard palate. The result is a fairly complete view of the tongue within the vocal tract at sampling rates appropriate for running speech. A comparison with other imaging vocal tract systems will be presented. [Work supported by NIH Grant DC-02717.

Noncontact ultrasound imaging applied to cortical bone phantoms

PubMed Central

Bulman, J. B.; Ganezer, K. S.; Halcrow, P. W.; Neeson, Ian

2012-01-01

Purpose: The purpose of this paper was to take the first steps toward applying noncontact ultrasound (NCU) to the tasks of monitoring osteoporosis and quantitative ultrasound imaging (QUS) of cortical bone. The authors also focused on the advantages of NCU, such as its lack of reliance on a technologist to apply transducers and a layer of acoustical coupling gel, the ability of the transducers to operate autonomously as specified by preprogrammed software, and the likely reduction in statistical and systematic errors associated with the variability in the pressure applied by the clinician to the transmitting transducer that NCU might provide. The authors also undertook this study in order to find additional applications of NCU beyond its past limited usage in assessing the severity of third degree burns. Methods: A noncontact ultrasound imaging system using a pair of specially designed broadband, 1.5 MHz noncontact piezoelectric transducers and cortical bone phantoms, were used to determine bone mineral density (BMD), speed of sound (SOS), integrated response (IR), and ultrasonic transmittance. Air gaps of greater than 3 cm, two transmission and two reflection paths, and a digital signal processor were also used in the collection of data from phantoms of nominal mass densities that varied from 1.17 to 2.25 g/cm3 and in bone mineral density from 0 to 1.7 g/cm3. Results: Good correlations between known BMD and measured SOS, IR, and transmittance were obtained for all 17 phantoms, and methods for quantifying and minimizing sources of systematic errors were outlined. The BMD of the phantom sets extended through most of the in vivo range found in cortical bone. A total of 16–20 repeated measurements of the SOS, thickness, and IR for the phantom set that were conducted over a period of several months showed a small variation in the range of measurements of ±1%–2%. These NCU data were shown to be in agreement with similar results using contact ultrasound to be within

The comparison of measurement between ultrasound and computed tomography for abnormal degenerative facet joints: A STROBE-compliant article.

PubMed

Shi, Wen; Tian, Dan; Liu, Da; Yin, Jing; Huang, Ying

2017-08-01

Besides the study on examining facet joints of lumbar spine by ultrasound in normal population, there has not been any related report about examining normal facet joints of lumbar spine by ultrasound so far. This study was aimed to explore the feasibility of ultrasound assessment of lumber spine facet joints by comparing ultrasound measure values of normal and degenerative lumber spine facet joints, and by comparing measure values of ultrasound and computed tomography (CT) of degenerative lumber spine facet joints.This study included 15 patients who had chronic low back pain because of degenerative change in lumbar vertebrae, and 19 volunteers who did not have low back pain or pain in the lower limb. The ultrasound measure values (height [H] and width [W]) of normal and degenerative lumber spine facet joints were compared. And the differentiation between measure values (H and W) of ultrasound and CT of degenerative lumber spine facet joints was also analyzed.The ultrasound clearly showed abnormal facet joints lesion, which was characterized by hyperostosis on the edge of joints, bone destruction under joints, and thinner or thicker articular cartilage. There were significant differences between the ultrasound measure values of the normal (H: 1.26 ± 0.03 cm, W: 0.18 ± 0.01 cm) and abnormal facet joints (H: 1.43 ± 0.05 cm, W: 0.15 ± 0.02 cm) (all P < .05). However, there were no significant differences between the measure values of the ultrasound (H: 1.43 ± 0.17 cm, W: 0.15 ± 0.03 cm) and CT (H: 1.42 ± 0.16, W: 0.14 ± 0.03) of the degenerative lumber spine facet joints (all P > .05).Ultrasound can clearly show the structure of facet joints of lumbar spine. It is precise and feasible to assess facet joints of lumbar spine by ultrasound. This study has important significance for the diagnosis of lumbar facet joint degeneration.

The use of three-dimensional ultrasound does not improve training in fetal biometric measurements.

PubMed

Chan, Lin W; Ting, Yuen H; Lao, Terence T; Chau, Macy M C; Fung, Tak Y; Leung, Tak Y; Sahota, Daljit S; Lau, Tze K

2011-09-01

To investigate whether three-dimensional (3D) technology offers any advantage over two-dimensional (2D) ultrasound in fetal biometric measurement training. Ten midwives with no hands-on experience in ultrasound were randomized to receive training on 2D or 3D ultrasound fetal biometry assessment. Midwives were taught how to obtain fetal biometric measurements (biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL)) by a trainer. Subsequently, each midwife measured the parameters on another 10 fetuses. The same set of measurements was repeated by the trainer. The percentage deviation between the midwives' and the trainer's measurements was determined and compared between training groups. Time required for completion was recorded. Frozen images were reviewed by another sonographer to assess the image quality using a standardized scoring system. The median time for the complete set of measurements was significantly shorter in the 2D than in 3D group (13.4 min versus 17.8 min, P = 0.03). The mean percentage deviations did not reach statistical significance between the two groups except for FL (3.83% in 2D group versus 2.23% in 3D group (P = 0.046)). There were no significant differences in the quality scores. This study showed that the only demonstrable advantage of 3D ultrasound was a slightly more accurate measurement of FL, at the expense of a significantly longer time required.

Ultrasound capsule endoscopy: sounding out the future

PubMed Central

Stewart, Fraser; Lay, Holly; Cummins, Gerard; Newton, Ian P.; Desmulliez, Marc P. Y.; Steele, Robert J. C.; Näthke, Inke; Cochran, Sandy

2017-01-01

Video capsule endoscopy (VCE) has been of immense benefit in the diagnosis and management of gastrointestinal (GI) disorders since its introduction in 2001. However, it suffers from a number of well recognized deficiencies. Amongst these is the limited capability of white light imaging, which is restricted to analysis of the mucosal surface. Current capsule endoscopes are dependent on visual manifestation of disease and limited in regards to transmural imaging and detection of deeper pathology. Ultrasound capsule endoscopy (USCE) has the potential to overcome surface only imaging and provide transmural scans of the GI tract. The integration of high frequency microultrasound (µUS) into capsule endoscopy would allow high resolution transmural images and provide a means of both qualitative and quantitative assessment of the bowel wall. Quantitative ultrasound (QUS) can provide data in an objective and measurable manner, potentially reducing lengthy interpretation times by incorporation into an automated diagnostic process. The research described here is focused on the development of USCE and other complementary diagnostic and therapeutic modalities. Presently investigations have entered a preclinical phase with laboratory investigations running concurrently. PMID:28567381

Does Quantitative Tibial Ultrasound Predict Low Bone Mineral Density Defined by Dual Energy X-Ray Absorptiometry?

PubMed Central

Birtane, Murat; Ekuklu, Galip; Cermik, Fikret; Tuna, Filiz; Kokino, Siranus

2008-01-01

Purpose Efforts for the early detection of bone loss and subsequent fracture risk by quantitative ultrasound (QUS), which is a non-invasive, radiation free, and cheaper method, seem rational to reduce the management costs. We aimed in this study to assess the probable correlation of speed of sound (SOS) values obtained by QUS with bone mineral density (BMD) as measured by the gold standard method, dual energy X-ray absorptiometry (DEXA), and to investigate the diagnostic value of QUS to define low BMD. Materials and Methods One hundred twenty-two postmenopausal women having prior standard DEXA measurements were included in the study. Spine and proximal femur (neck, trochanter and Ward's triangle) BMD were assessed in a standard protocol by DEXA. The middle point of the right tibia was chosen for SOS measurement by tibial QUS. Results The SOS values were observed to be significantly higher in the normal BMD (t score > - 1) group at all measurement sites except for the lumbar region, when compared with the low BMD group (t score < - 1). SOS was negatively correlated with age (r = - 0.66) and month since menopause (r = - 0.57). The sensitivity, specificity, and positive and negative predictive values for QUS t score to diagnose low BMD did not seem to be satisfactory at either of the measurement sites. Conclusion Tibial SOS was correlated weakly with BMD values of femur and lumbar spine as measured by DEXA and its diagnostic value did not seem to be high for discriminating between normal and low BMD, at these sites. PMID:18581594

Prediction of neonatal respiratory morbidity by quantitative ultrasound lung texture analysis: a multicenter study.

PubMed

Palacio, Montse; Bonet-Carne, Elisenda; Cobo, Teresa; Perez-Moreno, Alvaro; Sabrià, Joan; Richter, Jute; Kacerovsky, Marian; Jacobsson, Bo; García-Posada, Raúl A; Bugatto, Fernando; Santisteve, Ramon; Vives, Àngels; Parra-Cordero, Mauro; Hernandez-Andrade, Edgar; Bartha, José Luis; Carretero-Lucena, Pilar; Tan, Kai Lit; Cruz-Martínez, Rogelio; Burke, Minke; Vavilala, Suseela; Iruretagoyena, Igor; Delgado, Juan Luis; Schenone, Mauro; Vilanova, Josep; Botet, Francesc; Yeo, George S H; Hyett, Jon; Deprest, Jan; Romero, Roberto; Gratacos, Eduard

2017-08-01

Prediction of neonatal respiratory morbidity may be useful to plan delivery in complicated pregnancies. The limited predictive performance of the current diagnostic tests together with the risks of an invasive procedure restricts the use of fetal lung maturity assessment. The objective of the study was to evaluate the performance of quantitative ultrasound texture analysis of the fetal lung (quantusFLM) to predict neonatal respiratory morbidity in preterm and early-term (<39.0 weeks) deliveries. This was a prospective multicenter study conducted in 20 centers worldwide. Fetal lung ultrasound images were obtained at 25.0-38.6 weeks of gestation within 48 hours of delivery, stored in Digital Imaging and Communication in Medicine format, and analyzed with quantusFLM. Physicians were blinded to the analysis. At delivery, perinatal outcomes and the occurrence of neonatal respiratory morbidity, defined as either respiratory distress syndrome or transient tachypnea of the newborn, were registered. The performance of the ultrasound texture analysis test to predict neonatal respiratory morbidity was evaluated. A total of 883 images were collected, but 17.3% were discarded because of poor image quality or exclusion criteria, leaving 730 observations for the final analysis. The prevalence of neonatal respiratory morbidity was 13.8% (101 of 730). The quantusFLM predicted neonatal respiratory morbidity with a sensitivity, specificity, positive and negative predictive values of 74.3% (75 of 101), 88.6% (557 of 629), 51.0% (75 of 147), and 95.5% (557 of 583), respectively. Accuracy was 86.5% (632 of 730) and positive and negative likelihood ratios were 6.5 and 0.3, respectively. The quantusFLM predicted neonatal respiratory morbidity with an accuracy similar to that previously reported for other tests with the advantage of being a noninvasive technique. Copyright © 2017. Published by Elsevier Inc.

Strain measurement of abdominal aortic aneurysm with real-time 3D ultrasound speckle tracking.

PubMed

Bihari, P; Shelke, A; Nwe, T H; Mularczyk, M; Nelson, K; Schmandra, T; Knez, P; Schmitz-Rixen, T

2013-04-01

Abdominal aortic aneurysm rupture is caused by mechanical vascular tissue failure. Although mechanical properties within the aneurysm vary, currently available ultrasound methods assess only one cross-sectional segment of the aorta. This study aims to establish real-time 3-dimensional (3D) speckle tracking ultrasound to explore local displacement and strain parameters of the whole abdominal aortic aneurysm. Validation was performed on a silicone aneurysm model, perfused in a pulsatile artificial circulatory system. Wall motion of the silicone model was measured simultaneously with a commercial real-time 3D speckle tracking ultrasound system and either with laser-scan micrometry or with video photogrammetry. After validation, 3D ultrasound data were collected from abdominal aortic aneurysms of five patients and displacement and strain parameters were analysed. Displacement parameters measured in vitro by 3D ultrasound and laser scan micrometer or video analysis were significantly correlated at pulse pressures between 40 and 80 mmHg. Strong local differences in displacement and strain were identified within the aortic aneurysms of patients. Local wall strain of the whole abdominal aortic aneurysm can be analysed in vivo with real-time 3D ultrasound speckle tracking imaging, offering the prospect of individual non-invasive rupture risk analysis of abdominal aortic aneurysms. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Agreement and reliability of pelvic floor measurements during contraction using three-dimensional pelvic floor ultrasound and virtual reality.

PubMed

Speksnijder, L; Rousian, M; Steegers, E A P; Van Der Spek, P J; Koning, A H J; Steensma, A B

2012-07-01

Virtual reality is a novel method of visualizing ultrasound data with the perception of depth and offers possibilities for measuring non-planar structures. The levator ani hiatus has both convex and concave aspects. The aim of this study was to compare levator ani hiatus volume measurements obtained with conventional three-dimensional (3D) ultrasound and with a virtual reality measurement technique and to establish their reliability and agreement. 100 symptomatic patients visiting a tertiary pelvic floor clinic with a normal intact levator ani muscle diagnosed on translabial ultrasound were selected. Datasets were analyzed using a rendered volume with a slice thickness of 1.5 cm at the level of minimal hiatal dimensions during contraction. The levator area (in cm(2)) was measured and multiplied by 1.5 to get the levator ani hiatus volume in conventional 3D ultrasound (in cm(3)). Levator ani hiatus volume measurements were then measured semi-automatically in virtual reality (cm(3) ) using a segmentation algorithm. An intra- and interobserver analysis of reliability and agreement was performed in 20 randomly chosen patients. The mean difference between levator ani hiatus volume measurements performed using conventional 3D ultrasound and virtual reality was 0.10 (95% CI, - 0.15 to 0.35) cm(3). The intraclass correlation coefficient (ICC) comparing conventional 3D ultrasound with virtual reality measurements was > 0.96. Intra- and interobserver ICCs for conventional 3D ultrasound measurements were > 0.94 and for virtual reality measurements were > 0.97, indicating good reliability for both. Levator ani hiatus volume measurements performed using virtual reality were reliable and the results were similar to those obtained with conventional 3D ultrasonography. Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.

Relationships Between Quantitative Pulse-Echo Ultrasound Parameters from the Superficial Zone of the Human Articular Cartilage and Changes in Surface Roughness, Collagen Content or Collagen Orientation Caused by Early Degeneration.

PubMed

Kiyan, Wataru; Ito, Akira; Nakagawa, Yasuaki; Mukai, Shogo; Mori, Koji; Arai, Tatsuo; Uchino, Eiichiro; Okuno, Yasushi; Kuroki, Hiroshi

2017-08-01

We aimed to quantitatively investigate the relationship between amplitude-based pulse-echo ultrasound parameters and early degeneration of the knee articular cartilage. Twenty samples from six human femoral condyles judged as grade 0 or 1 according to International Cartilage Repair Society grading were assessed using a 15-MHz pulsed-ultrasound 3-D scanning system ex vivo. Surface roughness (R q ), average collagen content (A 1 ) and collagen orientation (A 12 ) in the superficial zone of the cartilage were measured via laser microscopy and Fourier transform infrared imaging spectroscopy. Multiple regression analysis with a linear mixed-effects model (LMM) revealed that a time-domain reflection coefficient at the cartilage surface (R c ) had a significant coefficient of determination with R q and A 12 (R LMMm 2 =0.79); however, R c did not correlate with A 1 . Concerning the collagen characteristic in the superficial zone, R c was found to be a sensitive indicator reflecting collagen disorganization, not collagen content, for the early degeneration samples. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Contrast-enhanced and targeted ultrasound.

PubMed

Postema, Michiel; Gilja, Odd Helge

2011-01-07

Ultrasonic imaging is becoming the most popular medical imaging modality, owing to the low price per examination and its safety. However, blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies. For perfusion imaging, markers have been designed to enhance the contrast in B-mode imaging. These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells. In this review, the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described. Furthermore, an outline of clinical imaging applications of contrast-enhanced ultrasound is given. It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition, and how these phenomena may be utilized in ultrasonic imaging. Aided by high-speed photography, our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques. More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves, and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs. These are beginning to be accepted into clinical practice. In the long term, targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested.

Contrast-enhanced and targeted ultrasound

PubMed Central

Postema, Michiel; Gilja, Odd Helge

2011-01-01

Ultrasonic imaging is becoming the most popular medical imaging modality, owing to the low price per examination and its safety. However, blood is a poor scatterer of ultrasound waves at clinical diagnostic transmit frequencies. For perfusion imaging, markers have been designed to enhance the contrast in B-mode imaging. These so-called ultrasound contrast agents consist of microscopically small gas bubbles encapsulated in biodegradable shells. In this review, the physical principles of ultrasound contrast agent microbubble behavior and their adjustment for drug delivery including sonoporation are described. Furthermore, an outline of clinical imaging applications of contrast-enhanced ultrasound is given. It is a challenging task to quantify and predict which bubble phenomenon occurs under which acoustic condition, and how these phenomena may be utilized in ultrasonic imaging. Aided by high-speed photography, our improved understanding of encapsulated microbubble behavior will lead to more sophisticated detection and delivery techniques. More sophisticated methods use quantitative approaches to measure the amount and the time course of bolus or reperfusion curves, and have shown great promise in revealing effective tumor responses to anti-angiogenic drugs in humans before tumor shrinkage occurs. These are beginning to be accepted into clinical practice. In the long term, targeted microbubbles for molecular imaging and eventually for directed anti-tumor therapy are expected to be tested. PMID:21218081

An ultrasound wearable system for the monitoring and acceleration of fracture healing in long bones.

PubMed

Protopappas, Vasilios C; Baga, Dina A; Fotiadis, Dimitrios I; Likas, Aristidis C; Papachristos, Athanasios A; Malizos, Konstantinos N

2005-09-01

An ultrasound wearable system for remote monitoring and acceleration of the healing process in fractured long bones is presented. The so-called USBone system consists of a pair of ultrasound transducers, implanted into the fracture region, a wearable device and a centralized unit. The wearable device is responsible to carry out ultrasound measurements using the axial-transmission technique and initiate therapy sessions of low-intensity pulsed ultrasound. The acquired measurements and other data are wirelessly transferred from the patient-site to the centralized unit, which is located in a clinical setting. The evaluation of the system on an animal tibial osteotomy model is also presented. A dataset was constructed for monitoring purposes consisting of serial ultrasound measurements, follow-up radiographs, quantitative computed tomography-based densitometry and biomechanical data. The animal study demonstrated the ability of the system to collect ultrasound measurements in an effective and reliable fashion and participating orthopaedic surgeons accepted the system for future clinical application. Analysis of the acquired measurements showed that the pattern of evolution of the ultrasound velocity through healing bones over the postoperative period monitors a dynamic healing process. Furthermore, the ultrasound velocity of radiographically healed bones returns to 80% of the intact bone value, whereas the correlation coefficient of the velocity with the material and mechanical properties of the healing bone ranges from 0.699 to 0.814. The USBone system constitutes the first telemedicine system for the out-hospital management of patients sustained open fractures and treated with external fixation devices.

Contrast imaging in mouse embryos using high-frequency ultrasound.

PubMed

Denbeigh, Janet M; Nixon, Brian A; Puri, Mira C; Foster, F Stuart

2015-03-04

Ultrasound contrast-enhanced imaging can convey essential quantitative information regarding tissue vascularity and perfusion and, in targeted applications, facilitate the detection and measure of vascular biomarkers at the molecular level. Within the mouse embryo, this noninvasive technique may be used to uncover basic mechanisms underlying vascular development in the early mouse circulatory system and in genetic models of cardiovascular disease. The mouse embryo also presents as an excellent model for studying the adhesion of microbubbles to angiogenic targets (including vascular endothelial growth factor receptor 2 (VEGFR2) or αvβ3) and for assessing the quantitative nature of molecular ultrasound. We therefore developed a method to introduce ultrasound contrast agents into the vasculature of living, isolated embryos. This allows freedom in terms of injection control and positioning, reproducibility of the imaging plane without obstruction and motion, and simplified image analysis and quantification. Late gestational stage (embryonic day (E)16.6 and E17.5) murine embryos were isolated from the uterus, gently exteriorized from the yolk sac and microbubble contrast agents were injected into veins accessible on the chorionic surface of the placental disc. Nonlinear contrast ultrasound imaging was then employed to collect a number of basic perfusion parameters (peak enhancement, wash-in rate and time to peak) and quantify targeted microbubble binding in an endoglin mouse model. We show the successful circulation of microbubbles within living embryos and the utility of this approach in characterizing embryonic vasculature and microbubble behavior.

TH-A-207B-02: QIBA Ultrasound Elasticity Imaging System Biomarker Qualification and User Testing of Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garra, B.

Imaging of tissue elastic properties is a relatively new and powerful approach to one of the oldest and most important diagnostic tools. Imaging of shear wave speed with ultrasound is has been added to most high-end ultrasound systems. Understanding this exciting imaging mode aiding its most effective use in medicine can be a rewarding effort for medical physicists and other medical imaging and treatment professionals. Assuring consistent, quantitative measurements across the many ultrasound systems in a typical imaging department will constitute a major step toward realizing the great potential of this technique and other quantitative imaging. This session will targetmore » these two goals with two presentations. A. Basics and Current Implementations of Ultrasound Imaging of Shear Wave Speed and Elasticity - Shigao Chen, Ph.D. Learning objectives-To understand: Introduction: Importance of tissue elasticity measurement Strain vs. shear wave elastography (SWE), beneficial features of SWE The link between shear wave speed and material properties, influence of viscosity Generation of shear waves External vibration (Fibroscan) ultrasound radiation force Point push Supersonic push (Aixplorer) Comb push (GE Logiq E9) Detection of shear waves Motion detection from pulse-echo ultrasound Importance of frame rate for shear wave imaging Plane wave imaging detection How to achieve high effective frame rate using line-by-line scanners Shear wave speed calculation Time to peak Random sample consensus (RANSAC) Cross correlation Sources of bias and variation in SWE Tissue viscosity Transducer compression or internal pressure of organ Reflection of shear waves at boundaries B. Elasticity Imaging System Biomarker Qualification and User Testing of Systems – Brian Garra, M.D. Learning objectives-To understand: Goals Review the need for quantitative medical imaging Provide examples of quantitative imaging biomarkers Acquaint the participant with the purpose of the RSNA Quantitative

Contrast-enhanced ultrasound for quantitative assessment of portal pressure in canine liver fibrosis

PubMed Central

Zhai, Lin; Qiu, Lan-Yan; Zu, Yuan; Yan, Yan; Ren, Xiao-Zhuan; Zhao, Jun-Feng; Liu, Yu-Jiang; Liu, Ji-Bin; Qian, Lin-Xue

2015-01-01

AIM: To explore the feasibility of non-invasive quantitative estimation of portal venous pressure by contrast-enhanced ultrasound (CEUS) in a canine model. METHODS: Liver fibrosis was established in adult canines (Beagles; n = 14) by subcutaneous injection of carbon tetrachloride (CCl4). CEUS parameters, including the area under the time-intensity curve and intensity at portal/arterial phases (Qp/Qa and Ip/Ia, respectively), were used to quantitatively assess the blood flow ratio of the portal vein/hepatic artery at multiple time points. The free portal venous pressures (FPP) were measured by a multi-channel baroreceptor using a percutaneous approach at baseline and 8, 16, and 24 wk after CCl4 injections in each canine. Liver biopsies were obtained at the end of 8, 16, and 24 wk from each animal, and the stage of the fibrosis was assessed according to the Metavir scoring system. A Pearson correlation test was performed to compare the FPP with Qp/Qa and Ip/Ia. RESULTS: Pathologic examination of 42 biopsies from the 14 canines at weeks 8, 16, and 24 revealed that liver fibrosis was induced by CCl4 and represented various stages of liver fibrosis, including F0 (n = 3), F1 (n = 12), F2 (n = 14), F3 (n = 11), and F4 (n = 2). There were significant differences in the measurements of Qp/Qa (19.85 ± 3.30 vs 10.43 ± 1.21, 9.63 ± 1.03, and 8.77 ± 0.96) and Ip/Ia (1.77 ± 0.37 vs 1.03 ± 0.12, 0.83 ± 0.10, and 0.69 ± 0.13) between control and canine fibrosis at 8, 16, and 24 wk, respectively (all P < 0.001). There were statistically significant negative correlations between FPP and Qp/Qa (r = -0.707, P < 0.001), and between FPP and Ip/Ia (r = -0.759, P < 0.001) in the canine fibrosis model. Prediction of elevated FPP based on Qp/Qa and Ip/Ia was highly sensitive, as assessed by the area under the receiver operating curve (0.866 and 0.895, respectively). CONCLUSION: CEUS is a potential method to accurately, but non-invasively, estimate portal venous pressure through

Exploration Analysis of Carbon Dioxide Levels and Ultrasound Measures of the Eye During ISS Missions

NASA Technical Reports Server (NTRS)

Young, M.; Mason, S.; Schaefer, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Coble, C.; Gruschkus, S.; Law, J.; Alexander, D.;

Bayesian parameter estimation in spectral quantitative photoacoustic tomography

NASA Astrophysics Data System (ADS)

Pulkkinen, Aki; Cox, Ben T.; Arridge, Simon R.; Kaipio, Jari P.; Tarvainen, Tanja

2016-03-01

Photoacoustic tomography (PAT) is an imaging technique combining strong contrast of optical imaging to high spatial resolution of ultrasound imaging. These strengths are achieved via photoacoustic effect, where a spatial absorption of light pulse is converted into a measurable propagating ultrasound wave. The method is seen as a potential tool for small animal imaging, pre-clinical investigations, study of blood vessels and vasculature, as well as for cancer imaging. The goal in PAT is to form an image of the absorbed optical energy density field via acoustic inverse problem approaches from the measured ultrasound data. Quantitative PAT (QPAT) proceeds from these images and forms quantitative estimates of the optical properties of the target. This optical inverse problem of QPAT is illposed. To alleviate the issue, spectral QPAT (SQPAT) utilizes PAT data formed at multiple optical wavelengths simultaneously with optical parameter models of tissue to form quantitative estimates of the parameters of interest. In this work, the inverse problem of SQPAT is investigated. Light propagation is modelled using the diffusion equation. Optical absorption is described with chromophore concentration weighted sum of known chromophore absorption spectra. Scattering is described by Mie scattering theory with an exponential power law. In the inverse problem, the spatially varying unknown parameters of interest are the chromophore concentrations, the Mie scattering parameters (power law factor and the exponent), and Gruneisen parameter. The inverse problem is approached with a Bayesian method. It is numerically demonstrated, that estimation of all parameters of interest is possible with the approach.

Validation of an ultrasound dilution technology for cardiac output measurement and shunt detection in infants and children.

PubMed

Lindberg, Lars; Johansson, Sune; Perez-de-Sa, Valeria

2014-02-01

To validate cardiac output measurements by ultrasound dilution technology (COstatus monitor) against those obtained by a transit-time ultrasound technology with a perivascular flow probe and to investigate ultrasound dilution ability to estimate pulmonary to systemic blood flow ratio in children. Prospective observational clinical trial. Pediatric cardiac operating theater in a university hospital. In 21 children (6.1 ± 2.6 kg, mean ± SD) undergoing heart surgery, cardiac output was simultaneously recorded by ultrasound dilution (extracorporeal arteriovenous loop connected to existing arterial and central venous catheters) and a transit-time ultrasound probe applied to the ascending aorta, and when possible, the main pulmonary artery. The pulmonary to systemic blood flow ratio estimated from ultrasound dilution curve analysis was compared with that estimated from transit-time ultrasound technology. Bland-Altman analysis of the whole cohort (90 pairs, before and after surgery) showed a bias between transit-time ultrasound (1.01 ± 0.47 L/min) and ultrasound dilution technology (1.03 ± 0.51 L/min) of -0.02 L/min, limits of agreement -0.3 to 0.3 L/min, and percentage error of 31%. In children with no residual shunts, the bias was -0.04 L/min, limits of agreement -0.28 to 0.2 L/min, and percentage error 19%. The pooled co efficient of variation was for the whole cohort 3.5% (transit-time ultrasound) and 6.3% (ultrasound dilution), and in children without shunt, it was 2.9% (transit-time ultrasound) and 4% (ultrasound dilution), respectively. Ultrasound dilution identified the presence of shunts (pulmonary to systemic blood flow ≠ 1) with a sensitivity of 100% and a specificity of 92%. Mean pulmonary to systemic blood flow ratio by transit-time ultrasound was 2.6 ± 1.0 and by ultrasound dilution 2.2 ± 0.7 (not significant). The COstatus monitor is a reliable technique to measure cardiac output in children with high sensitivity and specificity for detecting the

Design and implementation of a smartphone-based portable ultrasound pulsed-wave Doppler device for blood flow measurement.

PubMed

Huang, Chih-Chung; Lee, Po-Yang; Chen, Pay-Yu; Liu, Ting-Yu

2012-01-01

Blood flow measurement using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological monitor. Recently, pocket-sized ultrasound scanners have been introduced for portable diagnosis. The present paper reports the implementation of a portable ultrasound pulsed-wave (PW) Doppler flowmeter using a smartphone. A 10-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional baseband Doppler shift signals were obtained using a portable analog circuit system. After hardware processing, the Doppler signals were fed directly to a smartphone for Doppler spectrogram analysis and display in real time. To the best of our knowledge, this is the first report of the use of this system for medical ultrasound Doppler signal processing. A Couette flow phantom, consisting of two parallel disks with a 2-mm gap, was used to evaluate and calibrate the device. Doppler spectrograms of porcine blood flow were measured using this stand-alone portable device under the pulsatile condition. Subsequently, in vivo portable system verification was performed by measuring the arterial blood flow of a rat and comparing the results with the measurement from a commercial ultrasound duplex scanner. All of the results demonstrated the potential for using a smartphone as a novel embedded system for portable medical ultrasound applications. © 2012 IEEE

What are the characteristics of breast cancers misclassified as benign by quantitative ultrasound shear wave elastography?

PubMed

Vinnicombe, S J; Whelehan, P; Thomson, K; McLean, D; Purdie, C A; Jordan, L B; Hubbard, S; Evans, A J

2014-04-01

Shear wave elastography (SWE) is a promising adjunct to greyscale ultrasound in differentiating benign from malignant breast masses. The purpose of this study was to characterise breast cancers which are not stiff on quantitative SWE, to elucidate potential sources of error in clinical application of SWE to evaluation of breast masses. Three hundred and two consecutive patients examined by SWE who underwent immediate surgery for breast cancer were included. Characteristics of 280 lesions with suspicious SWE values (mean stiffness >50 kPa) were compared with 22 lesions with benign SWE values (<50 kPa). Statistical significance of the differences was assessed using non-parametric goodness-of-fit tests. Pure ductal carcinoma in situ (DCIS) masses were more often soft on SWE than masses representing invasive breast cancer. Invasive cancers that were soft were more frequently: histological grade 1, tubular subtype, ≤10 mm invasive size and detected at screening mammography. No significant differences were found with respect to the presence of invasive lobular cancer, vascular invasion, hormone and HER-2 receptor status. Lymph node positivity was less common in soft cancers. Malignant breast masses classified as benign by quantitative SWE tend to have better prognostic features than those correctly classified as malignant. • Over 90 % of cancers assessable with ultrasound have a mean stiffness >50 kPa. • 'Soft' invasive cancers are frequently small (≤10 mm), low grade and screen-detected. • Pure DCIS masses are more often soft than invasive cancers (>40 %). • Large symptomatic masses are better evaluated with SWE than small clinically occult lesions. • When assessing small lesions, 'softness' should not raise the threshold for biopsy.

Ultrasound Velocity Measurements in High-Chromium Steel Under Plastic Deformation

NASA Astrophysics Data System (ADS)

Lunev, Aleksey; Bochkareva, Anna; Barannikova, Svetlana; Zuev, Lev

2016-04-01

In the present study, the variation of the propagation velocity of ultrasound in the plastic deformation of corrosion-resistant high-chromium steel 40X13 with ferrite-carbide (delivery status), martensitic (quenched) and sorbitol (after high-temperature tempering) structures have beem studied/ It is found that each state shows its view of the loading curve. In the delivery state diagram loading is substantially parabolic throughout, while in the martensitic state contains only linear strain hardening step and in the sorbitol state the plastic flow curve is three-step. The velocity of ultrasonic surface waves (Rayleigh waves) was measured simultaneously with the registration of the loading curve in the investigated steel in tension. It is shown that the dependence of the velocity of ultrasound in active loading is determined by the law of plastic flow, that is, the staging of the corresponding diagram of loading. Structural state of the investigated steel is not only changing the type of the deformation curve under uniaxial tension, but also changes the nature of ultrasound speed of deformation.

Noncontact measurement of vibration using airborne ultrasound.

PubMed

Mater, O B; Remenieras, J P; Bruneel, C; Roncin, A; Patat, F

1998-01-01

A noncontact ultrasonic method for measuring the surface normal vibration of objects was studied. The instrument consists of a pair of 420 kHz ultrasonic air transducers. One is used to emit ultrasounds toward the moving surface, and the other receives the ultrasound reflected from the object under test. Two effects induce a phase modulation on the received signal. The first effect results from the variation of the round trip time interval tau required for the wavefront to go from the emitter to the moving surface and back to the receiver. This is the Doppler effect directly proportional to the surface displacement. The second effect results from the nonlinear parametric interactions of the ultrasonic beams (forward and backward) with the low frequency sound field emitted in the air by the vibrating surface. This latter phenomenon, which is a volume effect, is proportional to the velocity of the vibrating surface and increases with the distance between the transducers and the surface under test. The relative contribution of the Doppler and parametric effects are evaluated, and both have to be taken into account for ultrasonic interferometry in air.

Automated 3D ultrasound measurement of the angle of progression in labor.

PubMed

Montaguti, Elisa; Rizzo, Nicola; Pilu, Gianluigi; Youssef, Aly

2018-01-01

To assess the feasibility and reliability of an automated technique for the assessment of the angle of progression (AoP) in labor by using three-dimensional (3D) ultrasound. AoP was assessed by using 3D transperineal ultrasound by two operators in 52 women in active labor to evaluate intra- and interobserver reproducibility. Furthermore, intermethod agreement between automated and manual techniques on 3D images, and between automated technique on 3D vs 2D images were evaluated. Automated measurements were feasible in all cases. Automated measurements were considered acceptable in 141 (90.4%) out of the 156 on the first assessments and in all 156 after repeating measurements for unacceptable evaluations. The automated technique on 3D images demonstrated good intra- and interobserver reproducibility. The 3D-automated technique showed a very good agreement with the 3D manual technique. Notably, AoP calculated with the 3D automated technique were significantly wider in comparison with those measured manually on 3D images (133 ± 17° vs 118 ± 21°, p = 0.013). The assessment of the angle of progression through 3D ultrasound is highly reproducible. However, automated software leads to a systematic overestimation of AoP in comparison with the standard manual technique thus hindering its use in clinical practice in its present form.

Measurement of ventricular torsion by two-dimensional ultrasound speckle tracking imaging.

PubMed

Notomi, Yuichi; Lysyansky, Peter; Setser, Randolph M; Shiota, Takahiro; Popović, Zoran B; Martin-Miklovic, Maureen G; Weaver, Joan A; Oryszak, Stephanie J; Greenberg, Neil L; White, Richard D; Thomas, James D

2005-06-21

We sought to examine the accuracy/consistency of a novel ultrasound speckle tracking imaging (STI) method for left ventricular torsion (LVtor) measurement in comparison with tagged magnetic resonance imaging (MRI) (a time-domain method similar to STI) and Doppler tissue imaging (DTI) (a velocity-based approach). Left ventricular torsion from helically oriented myofibers is a key parameter of cardiac performance but is difficult to measure. Ultrasound STI is potentially suitable for measurement of angular motion because of its angle-independence. We acquired basal and apical short-axis left ventricular (LV) images in 15 patients to estimate LVtor by STI and compare it with tagged MRI and DTI. Left ventricular torsion was defined as the net difference of LV rotation at the basal and apical planes. For the STI analysis, we used high-frame (104 +/- 12 frames/s) second harmonic two-dimensional images. Data on 13 of 15 patients were usable for STI analysis, and LVtor profile estimated by STI strongly correlated with those by tagged MRI (y = 0.95x + 0.19, r = 0.93, p < 0.0001, analyzed by repeated-measures regression models). The STI torsional velocity profile also correlated well with that by the DTI method (y = 0.79x + 2.4, r = 0.76, p < 0.0001, by repeated-measures regression models) with acceptable bias. The STI estimation of LVtor is concordant with those analyzed by tagged MRI (data derived from tissue displacement) and also showed good agreement with those by DTI (data derived from tissue velocity). Ultrasound STI is a promising new method to assess LV torsional deformation and may make the assessment more available in clinical and research cardiology.

Quantitative evaluation of contrast-enhanced ultrasound after intravenous administration of a microbubble contrast agent for differentiation of benign and malignant thyroid nodules: assessment of diagnostic accuracy.

PubMed

Nemec, Ursula; Nemec, Stefan F; Novotny, Clemens; Weber, Michael; Czerny, Christian; Krestan, Christian R

2012-06-01

To investigate the diagnostic accuracy, through quantitative analysis, of contrast-enhanced ultrasound (CEUS), using a microbubble contrast agent, in the differentiation of thyroid nodules. This prospective study enrolled 46 patients with solitary, scintigraphically non-functional thyroid nodules. These patients were scheduled for surgery and underwent preoperative CEUS with pulse-inversion harmonic imaging after intravenous microbubble contrast medium administration. Using histology as a standard of reference, time-intensity curves of benign and malignant nodules were compared by means of peak enhancement and wash-out enhancement relative to the baseline intensity using a mixed model ANOVA. ROC analysis was performed to assess the diagnostic accuracy in the differentiation of benign and malignant nodules on CEUS. The complete CEUS data of 42 patients (31/42 [73.8%] benign and 11/42 [26.2%] malignant nodules) revealed a significant difference (P < 0.001) in enhancement between benign and malignant nodules. Furthermore, based on ROC analysis, CEUS demonstrated sensitivity of 76.9%, specificity of 84.8% and accuracy of 82.6%. Quantitative analysis of CEUS using a microbubble contrast agent allows the differentiation of benign and malignant thyroid nodules and may potentially serve, in addition to grey-scale and Doppler ultrasound, as an adjunctive tool in the assessment of patients with thyroid nodules. • Contrast-enhanced ultrasound (CEUS) helps differentiate between benign and malignant thyroid nodules. • Quantitative CEUS analysis yields sensitivity of 76.9% and specificity of 84.8%. • CEUS may be a potentially useful adjunct in assessing thyroid nodules.

A continuous-wave ultrasound system for displacement amplitude and phase measurement.

PubMed

Finneran, James J; Hastings, Mardi C

2004-06-01

A noninvasive, continuous-wave ultrasonic technique was developed to measure the displacement amplitude and phase of mechanical structures. The measurement system was based on a method developed by Rogers and Hastings ["Noninvasive vibration measurement system and method for measuring amplitude of vibration of tissue in an object being investigated," U.S. Patent No. 4,819,643 (1989)] and expanded to include phase measurement. A low-frequency sound source was used to generate harmonic vibrations in a target of interest. The target was simultaneously insonified by a low-power, continuous-wave ultrasonic source. Reflected ultrasound was phase modulated by the target motion and detected with a separate ultrasonic transducer. The target displacement amplitude was obtained directly from the received ultrasound frequency spectrum by comparing the carrier and sideband amplitudes. Phase information was obtained by demodulating the received signal using a double-balanced mixer and low-pass filter. A theoretical model for the ultrasonic receiver field is also presented. This model coupled existing models for focused piston radiators and for pulse-echo ultrasonic fields. Experimental measurements of the resulting receiver fields compared favorably with theoretical predictions.

Portable Bladder Ultrasound

PubMed Central

2006-01-01

Executive Summary Objective The aim of this review was to assess the clinical utility of portable bladder ultrasound. Clinical Need: Target Population and Condition Data from the National Population Health Survey indicate prevalence rates of urinary incontinence are 2.5% in women and 1.4 % in men in the general population. Prevalence of urinary incontinence is higher in women than men and prevalence increases with age. Identified risk factors for urinary incontinence include female gender, increasing age, urinary tract infections (UTI), poor mobility, dementia, smoking, obesity, consuming alcohol and caffeine beverages, physical activity, pregnancy, childbirth, forceps and vacuum-assisted births, episiotomy, abdominal resection for colorectal cancer, and hormone replacement therapy. For the purposes of this review, incontinence populations will be stratified into the following; the elderly, urology patients, postoperative patients, rehabilitation settings, and neurogenic bladder populations. Urinary incontinence is defined as any involuntary leakage of urine. Incontinence can be classified into diagnostic clinical types that are useful in planning evaluation and treatment. The major types of incontinence are stress (physical exertion), urge (overactive bladder), mixed (combined urge and stress urinary incontinence), reflex (neurological impairment of the central nervous system), overflow (leakage due to full bladder), continuous (urinary tract abnormalities), congenital incontinence, and transient incontinence (temporary incontinence). Postvoid residual (PVR) urine volume, which is the amount of urine in the bladder immediately after urination, represents an important component in continence assessment and bladder management to provide quantitative feedback to the patient and continence care team regarding the effectiveness of the voiding technique. Although there is no standardized definition of normal PVR urine volume, measurements greater than 100 mL to 150 m

Fetal head detection and measurement in ultrasound images by an iterative randomized Hough transform

NASA Astrophysics Data System (ADS)

Lu, Wei; Tan, Jinglu; Floyd, Randall C.

2004-05-01

This paper describes an automatic method for measuring the biparietal diameter (BPD) and head circumference (HC) in ultrasound fetal images. A total of 217 ultrasound images were segmented by using a K-Mean classifier, and the head skull was detected in 214 of the 217 cases by an iterative randomized Hough transform developed for detection of incomplete curves in images with strong noise without user intervention. The automatic measurements were compared with conventional manual measurements by sonographers and a trained panel. The inter-run variations and differences between the automatic and conventional measurements were small compared with published inter-observer variations. The results showed that the automated measurements were as reliable as the expert measurements and more consistent. This method has great potential in clinical applications.

TH-A-207B-01: Basics and Current Implementations of Ultrasound Imaging of Shear Wave Speed and Elasticity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, S.

Imaging of tissue elastic properties is a relatively new and powerful approach to one of the oldest and most important diagnostic tools. Imaging of shear wave speed with ultrasound is has been added to most high-end ultrasound systems. Understanding this exciting imaging mode aiding its most effective use in medicine can be a rewarding effort for medical physicists and other medical imaging and treatment professionals. Assuring consistent, quantitative measurements across the many ultrasound systems in a typical imaging department will constitute a major step toward realizing the great potential of this technique and other quantitative imaging. This session will targetmore » these two goals with two presentations. A. Basics and Current Implementations of Ultrasound Imaging of Shear Wave Speed and Elasticity - Shigao Chen, Ph.D. Learning objectives-To understand: Introduction: Importance of tissue elasticity measurement Strain vs. shear wave elastography (SWE), beneficial features of SWE The link between shear wave speed and material properties, influence of viscosity Generation of shear waves External vibration (Fibroscan) ultrasound radiation force Point push Supersonic push (Aixplorer) Comb push (GE Logiq E9) Detection of shear waves Motion detection from pulse-echo ultrasound Importance of frame rate for shear wave imaging Plane wave imaging detection How to achieve high effective frame rate using line-by-line scanners Shear wave speed calculation Time to peak Random sample consensus (RANSAC) Cross correlation Sources of bias and variation in SWE Tissue viscosity Transducer compression or internal pressure of organ Reflection of shear waves at boundaries B. Elasticity Imaging System Biomarker Qualification and User Testing of Systems – Brian Garra, M.D. Learning objectives-To understand: Goals Review the need for quantitative medical imaging Provide examples of quantitative imaging biomarkers Acquaint the participant with the purpose of the RSNA Quantitative

Applications of Doppler ultrasound in clinical vascular disease

NASA Technical Reports Server (NTRS)

Barnes, R. W.; Hokanson, D. E.; Sumner, D. S.; Strandness, D. E., Jr.

1975-01-01

Doppler ultrasound has become the most useful and versatile noninvasive technique for objective evaluation of clinical vascular disease. Commercially available continuous-wave instruments provide qualitative and quantitative assessment of venous and arterial disease. Pulsed Doppler ultrasound was developed to provide longitudinal and transverse cross-sectional images of the arterial lumen with a resolution approaching that of conventional X-ray techniques. Application of Doppler ultrasound in venous, peripheral arterial, and cerebrovascular diseases is reviewed.

Comparison of central corneal thickness measurements using ultrasound pachymetry, ultrasound biomicroscopy, and the Artemis-2 VHF scanner in normal eyes

PubMed Central

Al-Farhan, Haya M; Al-Otaibi, Wafa’a Majed

2012-01-01

Purpose To compare the precision of central corneal thickness (CCT) measurements taken with the handheld ultrasound pachymeter (USP), ultrasound biomicroscopy (UBM), and the Artemis-2 very high frequency ultrasound scanner (VHFUS) on normal subjects. Design Prospective study. Methods One eye from each of 61 normal subjects was randomly selected for this study. The measurements of the CCT were taken with the USP, VHFUS, and UBM. Results were compared statistically using repeated-measures analysis of variance (ANOVA), Pearson’s correlation coefficient, and limits of agreement. Results The average CCT (± standard deviation) was 530.1 ± 30.5 μm, 554.9 ± 31.7 μm, and 559.5 ± 30.7 μm for UBM, VHFUS, and USP respectively. The intraobserver repeatability analyses of variance are not significant for USP, UBM, and VHFUS. P-values were 0.17, 0.19, and 0.37 respectively. Repeated-measures ANOVA showed a significant difference between the three different methods of measuring CCT (P = 0.0001). The ANOVA test revealed no statistically significant difference between USP and VHFUS (P > 0.05), yet statistical significant differences with UBM versus USP and UBM versus VHFUS (P < 0.001). There were high correlations between the three instruments (P < 0.0001). The mean differences (and upper/lower limits of agreement) for CCT measurements were 29.4 ± 14.3 (2.7/56), 4.6 ± 8.6 (−14.7/23.8), and −24.8 ± 13.1 (−50.4/0.8) for USP versus UBM, USP versus VHFUS, and UBM versus VHFUS, respectively. Conclusion The UBM produces CCT measurements that vary significantly from those returned by the USP and the VHFUS, suggesting that the UBM may not be used interchangeably with either equipment for monitoring the CCT in the clinical setting. PMID:22848145

Quantitative correlational study of microbubble-enhanced ultrasound imaging and magnetic resonance imaging of glioma and early response to radiotherapy in a rat model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Chen; Lee, Dong-Hoon; Zhang, Kai

Purpose: Radiotherapy remains a major treatment method for malignant tumors. Magnetic resonance imaging (MRI) is the standard modality for assessing glioma treatment response in the clinic. Compared to MRI, ultrasound imaging is low-cost and portable and can be used during intraoperative procedures. The purpose of this study was to quantitatively compare contrast-enhanced ultrasound (CEUS) imaging and MRI of irradiated gliomas in rats and to determine which quantitative ultrasound imaging parameters can be used for the assessment of early response to radiation in glioma. Methods: Thirteen nude rats with U87 glioma were used. A small thinned skull window preparation was performedmore » to facilitate ultrasound imaging and mimic intraoperative procedures. Both CEUS and MRI with structural, functional, and molecular imaging parameters were performed at preradiation and at 1 day and 4 days postradiation. Statistical analysis was performed to determine the correlations between MRI and CEUS parameters and the changes between pre- and postradiation imaging. Results: Area under the curve (AUC) in CEUS showed significant difference between preradiation and 4 days postradiation, along with four MRI parameters, T{sub 2}, apparent diffusion coefficient, cerebral blood flow, and amide proton transfer-weighted (APTw) (all p < 0.05). The APTw signal was correlated with three CEUS parameters, rise time (r = − 0.527, p < 0.05), time to peak (r = − 0.501, p < 0.05), and perfusion index (r = 458, p < 0.05). Cerebral blood flow was correlated with rise time (r = − 0.589, p < 0.01) and time to peak (r = − 0.543, p < 0.05). Conclusions: MRI can be used for the assessment of radiotherapy treatment response and CEUS with AUC as a new technique and can also be one of the assessment methods for early response to radiation in glioma.« less

Quantitative correlational study of microbubble-enhanced ultrasound imaging and magnetic resonance imaging of glioma and early response to radiotherapy in a rat model.

PubMed

Yang, Chen; Lee, Dong-Hoon; Mangraviti, Antonella; Su, Lin; Zhang, Kai; Zhang, Yin; Zhang, Bin; Li, Wenxiao; Tyler, Betty; Wong, John; Wang, Ken Kang-Hsin; Velarde, Esteban; Zhou, Jinyuan; Ding, Kai

2015-08-01

Radiotherapy remains a major treatment method for malignant tumors. Magnetic resonance imaging (MRI) is the standard modality for assessing glioma treatment response in the clinic. Compared to MRI, ultrasound imaging is low-cost and portable and can be used during intraoperative procedures. The purpose of this study was to quantitatively compare contrast-enhanced ultrasound (CEUS) imaging and MRI of irradiated gliomas in rats and to determine which quantitative ultrasound imaging parameters can be used for the assessment of early response to radiation in glioma. Thirteen nude rats with U87 glioma were used. A small thinned skull window preparation was performed to facilitate ultrasound imaging and mimic intraoperative procedures. Both CEUS and MRI with structural, functional, and molecular imaging parameters were performed at preradiation and at 1 day and 4 days postradiation. Statistical analysis was performed to determine the correlations between MRI and CEUS parameters and the changes between pre- and postradiation imaging. Area under the curve (AUC) in CEUS showed significant difference between preradiation and 4 days postradiation, along with four MRI parameters, T2, apparent diffusion coefficient, cerebral blood flow, and amide proton transfer-weighted (APTw) (all p < 0.05). The APTw signal was correlated with three CEUS parameters, rise time (r = - 0.527, p < 0.05), time to peak (r = - 0.501, p < 0.05), and perfusion index (r = 458, p < 0.05). Cerebral blood flow was correlated with rise time (r = - 0.589, p < 0.01) and time to peak (r = - 0.543, p < 0.05). MRI can be used for the assessment of radiotherapy treatment response and CEUS with AUC as a new technique and can also be one of the assessment methods for early response to radiation in glioma.

Quantitative ultrasound and dual-energy X-ray absorptiometry in the prediction of fragility fracture in men.

PubMed

Gonnelli, Stefano; Cepollaro, Chiara; Gennari, Luigi; Montagnani, Andrea; Caffarelli, Carla; Merlotti, Daniela; Rossi, Stefania; Cadirni, Alice; Nuti, Ranuccio

2005-08-01

Fragility fractures in men represent a major health problem, and this prompts a necessity for reliable tools for the identification of men at risk of fracture. In order to assess the ability of dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) in the prediction of fracture risk in men and whether their combination might be useful in a clinical setting, we studied 401 men (age range 45-82 years, mean 60.3+/-12.5), of whom 133 had osteoporotic fractures and 268 did not. In all subjects we measured bone mineral density at the lumbar spine (BMD-LS) and at the femur, calculating thereafter the standard femoral subregions: neck (BMD-FN), total hip (BMD-T), trochanter (BMD-TR), intertrochanter (BMD-ITR), and Ward's triangle (BMD-W), by DXA. We also performed ultrasound parameters at the calcaneus: speed of sound (SOS), broadband ultrasound attenuation (BUA) and Stiffness, by Achilles plus, and at the phalanxes: amplitude dependent speed of sound (AD-SoS) and the parameters of the graphic trace: bone transmission time (BTT), fast wave amplitude (FWA), signal dynamic (SDy) and ultrasound bone profile index (UBPI), by Bone Profiler. All DXA and QUS parameters, apart from FWA, were significantly (P<0.001) lower in patients with a history of fracture. BMD at the proximal femur showed the best ability in discriminating men with or without fractures. QUS at the heel showed discriminatory ability significantly better than QUS at the fingers. By logistic regression analysis, adjusted for age and BMI, BMD-T showed the best association with fragility fracture [odds ratio (OR)=3.43, 95% confidence interval (CI)=2.47-4.77]. Among QUS parameters, the highest value of the OR was shown by stiffness (OR=3.18, CI=2.27-4.48). FWA and SDy were not associated with fragility fractures in men. If DXA and QUS were combined, the prediction of the OR of fragility fracture events in men increases; in fact Stiffness was able to increase the OR when added to BMD-LS (OR=5.44, CI

Processing ultrasound backscatter to monitor high-intensity focused ultrasound (HIFU) therapy

NASA Astrophysics Data System (ADS)

Kaczkowski, Peter J.; Anand, Ajay; Bailey, Michael R.

2005-09-01

The development of new noninvasive surgical methods such as HIFU for the treatment of cancer and internal bleeding requires simultaneous development of new sensing approaches to guide, monitor, and assess the therapy. Ultrasound imaging using echo amplitude has long been used to map tissue morphology for diagnostic interpretation by the clinician. New quantitative ultrasonic methods that rely on amplitude and phase processing for tissue characterization are being developed for monitoring of ablative therapy. We have been developing the use of full wave ultrasound backscattering for real-time temperature estimation, and to image changes in tissue backscatter spectrum as therapy progresses. Both approaches rely on differential processing of the backscatter signal in time, and precise measurement of phase differences. Noise and artifacts from motion and nonstationary speckle statistics are addressed by constraining inversions for tissue parameters with physical models. We present results of HIFU experiments with static point and scanned HIFU exposures in which temperature rise can be accurately mapped using a new heat transfer equation (HTE) model-constrained inverse approach. We also present results of a recently developed spectral imaging method that elucidates microbubble-mediated nonlinearity not visible as a change in backscatter amplitude. [Work supported by Army MRMC.

MR-ARFI-based method for the quantitative measurement of tissue elasticity: application for monitoring HIFU therapy

NASA Astrophysics Data System (ADS)

Vappou, Jonathan; Bour, Pierre; Marquet, Fabrice; Ozenne, Valery; Quesson, Bruno

2018-05-01

Monitoring thermal therapies through medical imaging is essential in order to ensure that they are safe, efficient and reliable. In this paper, we propose a new approach, halfway between MR acoustic radiation force imaging (MR-ARFI) and MR elastography (MRE), allowing for the quantitative measurement of the elastic modulus of tissue in a highly localized manner. It relies on the simulation of the MR-ARFI profile, which depends on tissue biomechanical properties, and on the identification of tissue elasticity through the fitting of experimental displacement images measured using rapid MR-ARFI. This method was specifically developed to monitor MR-guided high intensity focused ultrasound (MRgHIFU) therapy. Elasticity changes were followed during HIFU ablations (N  =  6) performed ex vivo in porcine muscle samples, and were compared to temperature changes measured by MR-thermometry. Shear modulus was found to increase consistently and steadily a few seconds after the heating started, and such changes were found to be irreversible. The shear modulus was found to increase from 1.49  ±  0.48 kPa (before ablation) to 3.69  ±  0.93 kPa (after ablation and cooling). Thanks to its ability to perform quantitative elasticity measurements in a highly localized manner around the focal spot, this method proved to be particularly attractive for monitoring HIFU ablations.

The measurement of ultrasound scattering from individual micron-sized objects and its application in single cell scattering.

PubMed

Falou, Omar; Rui, Min; El Kaffas, Ahmed; Kumaradas, J Carl; Kolios, Michael C

2010-08-01

The measurement of the ultrasound backscatter from individual micron-sized objects such as cells is required for various applications such as tissue characterization. However, performing such a measurement remains a challenge. For example, the presence of air bubbles in a suspension of cells during the measurements may lead to the incorrect interpretation of the acoustic signals. This work introduces a technique for measuring the ultrasound backscatter from individual micron-sized objects by combining a microinjection system with a co-registered optical microscope and an ultrasound imaging device. This allowed the measurement of the ultrasound backscatter response from a single object under optical microscope guidance. The optical and ultrasonic data were used to determine the size of the object and to deduce its backscatter responses, respectively. In order to calibrate the system, the backscatter frequency responses from polystyrene microspheres were measured and compared to theoretical predictions. A very good agreement was found between the measured backscatter responses of individual microspheres and theoretical predictions of an elastic sphere. The backscatter responses from single OCI-AML-5 cells were also investigated. It was found that the backscatter responses from AML cells are best modeled using the fluid sphere model. The advantages, limitations, and future applications of the developed technique are discussed.

Measurement of carotid pulse wave velocity using ultrafast ultrasound imaging in hypertensive patients.

PubMed

Li, Xiaopeng; Jiang, Jue; Zhang, Hong; Wang, Hua; Han, Donggang; Zhou, Qi; Gao, Ya; Yu, Shanshan; Qi, Yanhua

2017-04-01

The study aimed to assess the utility of ultrafast ultrasound imaging for evaluation of carotid pulse wave velocity (PWV) in newly diagnosed hypertension patients. This prospective non-randomized study enrolled 90 hypertensive patients in our hospital from September to December 2013 as a hypertension group. An age- and sex-matched cohort of 50 healthy adults in our hospital from September to December 2013 was also included in the study as a control group. Carotid PWV at the beginning and at the end of systole (PWV-BS and PWV-ES, respectively) and intima-media thickness (IMT) were measured by ultrafast ultrasound imaging technology. The associations of PWV-BS, PWV-ES, and IMT with hypertension stage were evaluated by Spearman correlation analysis. PWV-BS and PWV-ES in the hypertension group were significantly elevated compared with those in control group. Different hypertension stages significantly differed in PWV-BS and PWV-ES. PWV-BS and PWV-ES appeared to increase with the hypertension stage. Moreover, IMT, PWV-BS, and PWV-ES were positively correlated with the hypertension stage in hypertensive patients. Ultrafast ultrasound imaging was a valid and convenient method for the measurement of carotid PWV in hypertensive patients. Ultrafast ultrasound imaging might be recommended as a promising alternative method for early detection of arterial abnormality in clinical practice.

Quantitative vibro-acoustography of tissue-like objects by measurement of resonant modes

NASA Astrophysics Data System (ADS)

Mazumder, Dibbyan; Umesh, Sharath; Mohan Vasu, Ram; Roy, Debasish; Kanhirodan, Rajan; Asokan, Sundarrajan

2017-01-01

We demonstrate a simple and computationally efficient method to recover the shear modulus pertaining to the focal volume of an ultrasound transducer from the measured vibro-acoustic spectral peaks. A model that explains the transport of local deformation information with the acoustic wave acting as a carrier is put forth. It is also shown that the peaks correspond to the natural frequencies of vibration of the focal volume, which may be readily computed by solving an eigenvalue problem associated with the vibrating region. Having measured the first natural frequency with a fibre Bragg grating sensor, and armed with an expedient means of computing the same, we demonstrate a simple procedure, based on the method of bisection, to recover the average shear modulus of the object in the ultrasound focal volume. We demonstrate this recovery for four homogeneous agarose slabs of different stiffness and verify the accuracy of the recovery using independent rheometer-based measurements. Extension of the method to anisotropic samples through the measurement of a more complete set of resonant modes and the recovery of an elasticity tensor distribution, as is done in resonant ultrasound spectroscopy, is suggested.

Measurement of Transcranial Distance During Head-Down Tilt Using Ultrasound

NASA Technical Reports Server (NTRS)

Torikoshi, Shigeyo; Ballard, R. E.; Watenpaugh, D. E.; Murthy, G.; Bowley, S.; Yost, W. T.; Hargens, Alan R.

1995-01-01

Exposure to microgravity probably elevates blood pressure and flow in the head which may increase intracranial volume (ICV) and pressure (ICP). Due to the slightly compliant nature of the cranium, any increase of ICP will increase ICV and transcranial distance. We used a noninvasive ultrasound technique to measure transcranial distance (frontal to occipital) during head-down tilt. Seven subjects (ages 26-53) underwent the following tilt angles: 90 deg. upright, 30 deg., 0 deg., -6 deg., -10 deg., -6 deg., 0 deg., 30 deg., and 90 deg. Each angle was maintained for 1 min. Ultrasound wave frequency was collected continuously and transcranial distance was calculated (Delta(x) = x(Delta)f/f, where x is path length and f is frequency of the wave) for each tilt angle. Frequency decreased from 503.687 kHz (90 deg. upright) to 502.619 kHz (-10 deg.). These frequencies translated to an increased transcranial distance of 0.403 mm. Although our data suggest a significant increase in transcranial distance during head-down tilt, this apparent increase may result, in part, from head-down tilt-induced subcutaneous edema or cutaneous blood volume elevation. In three subjects, when the above protocol was repeated with an ace bandage wrapped around the head to minimize such edema, the increased transcranial distance from 90 deg. to -10 deg. was reduced by 0.174 mm. Further development of the technique to quantify bone-to-bone expansion unconfounded by cutaneous fluid is necessary. Therefore, this ultrasound technique may provide measurements of changes in cranial dimensions during microgravity.

A Microfluidics-based Pulpal Arteriole Blood Flow Phantom for Validation of Doppler Ultrasound Devices in Pulpal Blood Flow Velocity Measurement.

PubMed

Kim, Dohyun; Park, Sung-Ho

2016-11-01

Recently, Doppler ultrasound has been used for the measurement of pulpal blood flow in human teeth. However, the reliability of this method has not been verified. In this study, we developed a model to simulate arteriole blood flow within the dental pulp by using microfluidics. This arteriole simulator, or flow phantom, was used to determine the reliability of measurements obtained by using a Doppler ultrasound device. A microfluidic chip was fabricated by using the soft lithography technique, and blood-mimicking fluid was pumped through the channel by a microfluidic system. A Doppler ultrasound device was used for the measurement of flow velocity. The peak, mean, and minimal flow velocities obtained from the phantom and the Doppler ultrasound device were compared by using linear regression analysis and Pearson correlation coefficient. Bland-Altman analyses were performed to evaluate the velocity differences between the flow generated by the phantom and the flow measurements made with the Doppler ultrasound device. The microfluidic system was able to generate the flow profiles as intended, and the fluid flow could be monitored and controlled by the software program. There were excellent linear correlations between the peak, mean, and minimal flow velocities of the phantom and those of the Doppler ultrasound device (r = 0.94-0.996, P < .001). However, the velocities were overestimated by the Doppler ultrasound device. This phantom provides opportunities for research and education involving the Doppler ultrasound technique in dentistry. Although Doppler ultrasound can be an effective tool for the measurement of pulpal blood flow velocity, it is essential to validate and calibrate the device before clinical use. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Signal processing in ultrasound. [for diagnostic medicine

NASA Technical Reports Server (NTRS)

Le Croissette, D. H.; Gammell, P. M.

1978-01-01

Signal is the term used to denote the characteristic in the time or frequency domain of the probing energy of the system. Processing of this signal in diagnostic ultrasound occurs as the signal travels through the ultrasonic and electrical sections of the apparatus. The paper discusses current signal processing methods, postreception processing, display devices, real-time imaging, and quantitative measurements in noninvasive cardiology. The possibility of using deconvolution in a single transducer system is examined, and some future developments using digital techniques are outlined.

Quantitative Ultrasound Assessment of Duchenne Muscular Dystrophy Using Edge Detection Analysis.

PubMed

Koppaka, Sisir; Shklyar, Irina; Rutkove, Seward B; Darras, Basil T; Anthony, Brian W; Zaidman, Craig M; Wu, Jim S

2016-09-01

The purpose of this study was to investigate the ability of quantitative ultrasound (US) using edge detection analysis to assess patients with Duchenne muscular dystrophy (DMD). After Institutional Review Board approval, US examinations with fixed technical parameters were performed unilaterally in 6 muscles (biceps, deltoid, wrist flexors, quadriceps, medial gastrocnemius, and tibialis anterior) in 19 boys with DMD and 21 age-matched control participants. The muscles of interest were outlined by a tracing tool, and the upper third of the muscle was used for analysis. Edge detection values for each muscle were quantified by the Canny edge detection algorithm and then normalized to the number of edge pixels in the muscle region. The edge detection values were extracted at multiple sensitivity thresholds (0.01-0.99) to determine the optimal threshold for distinguishing DMD from normal. Area under the receiver operating curve values were generated for each muscle and averaged across the 6 muscles. The average age in the DMD group was 8.8 years (range, 3.0-14.3 years), and the average age in the control group was 8.7 years (range, 3.4-13.5 years). For edge detection, a Canny threshold of 0.05 provided the best discrimination between DMD and normal (area under the curve, 0.96; 95% confidence interval, 0.84-1.00). According to a Mann-Whitney test, edge detection values were significantly different between DMD and controls (P < .0001). Quantitative US imaging using edge detection can distinguish patients with DMD from healthy controls at low Canny thresholds, at which discrimination of small structures is best. Edge detection by itself or in combination with other tests can potentially serve as a useful biomarker of disease progression and effectiveness of therapy in muscle disorders.

A new method for blood velocity measurements using ultrasound FMCW signals.

PubMed

Kunita, Masanori; Sudo, Masamitsu; Inoue, Shinya; Akahane, Mutsuhiro

2010-05-01

The low peak power of frequency-modulated continuous wave (FMCW) radar makes it attractive for various applications, including vehicle collision warning systems and airborne radio altimeters. This paper describes a new ultrasound Doppler measurement system that measures blood flow velocity based on principles similar to those of FMCW radar. We propose a sinusoidal wave for FM modulation and introduce a new demodulation technique for obtaining Doppler information with high SNR and range resolution. Doppler signals are demodulated with a reference FMCW signal to adjust delay times so that they are equal to propagation times between the transmitter and the receiver. Analytical results suggest that Doppler signals can be obtained from a selected position, as with a sample volume in pulse wave Doppler systems, and that the resulting SNR is nearly identical to that obtained with continuous wave (CW) Doppler systems. Additionally, clutter power is less than that of CW Doppler systems. The analytical results were verified by experiments involving electronic circuits and Doppler ultrasound phantoms.

Numerical Calculation and Measurement of Nonlinear Acoustic Fields in Ultrasound Diagnosis

NASA Astrophysics Data System (ADS)

Kawagishi, Tetsuya; Saito, Shigemi; Mine, Yoshitaka

2002-05-01

In order to develop a tool for designing on the ultrasonic probe and its peripheral devices for tissue-harmonic-imaging systems, a study is carried out to compare the calculation and observation results of nonlinear acoustic fields for a diagnostic ultrasound system. The pulsed ultrasound with a center frequency of 2.5 MHz is emanated from a weakly focusing sector probe with a 6.5 mm aperture radius and a 50 mm focal length into an agar phantom with an attenuation coefficient of about 0.6 dB/cm/MHz or 1.2 dB/cm/MHz. The nonlinear acoustic field is measured using a needle-type hydrophone. The calculation is based on the Khokhlov-Zabolotskaya-Kuznetsov(KZK) equation which is modified so that the frequency dependence of the attenuation coefficient is the same as that in biological tissue. This equation is numerically solved with the implicit backward method employing the iterative method. The measured and calculated amplitude spectra show good agreement with each other.

Superficial Ultrasound Shear Wave Speed Measurements in Soft and Hard Elasticity Phantoms: Repeatability and Reproducibility Using Two Different Ultrasound Systems

PubMed Central

Dillman, Jonathan R.; Chen, Shigao; Davenport, Matthew S.; Zhao, Heng; Urban, Matthew W.; Song, Pengfei; Watcharotone, Kuanwong; Carson, Paul L.

2014-01-01

Background There is a paucity of data available regarding the repeatability and reproducibility of superficial shear wave speed (SWS) measurements at imaging depths relevant to the pediatric population. Purpose To assess the repeatability and reproducibility of superficial shear wave speed (SWS) measurements acquired from elasticity phantoms at varying imaging depths using three different imaging methods, two different ultrasound systems, and multiple operators. Methods and Materials Soft and hard elasticity phantoms manufactured by Computerized Imaging Reference Systems, Inc. (Norfolk, VA) were utilized for our investigation. Institution #1 used an Acuson S3000 ultrasound system (Siemens Medical Solutions USA, Inc.) and three different shear wave imaging method/transducer combinations, while institution #2 used an Aixplorer ultrasound system (Supersonic Imagine) and two different transducers. Ten stiffness measurements were acquired from each phantom at three depths (1.0, 2.5, and 4.0 cm) by four operators at each institution. Student’s t-test was used to compare SWS measurements between imaging techniques, while SWS measurement agreement was assessed with two-way random effects single measure intra-class correlation coefficients and coefficients of variation. Mixed model regression analysis determined the effect of predictor variables on SWS measurements. Results For the soft phantom, the average of mean SWS measurements across the various imaging methods and depths was 0.84 ± 0.04 m/s (mean ± standard deviation) for the Acuson S3000 system and 0.90 ± 0.02 m/s for the Aixplorer system (p=0.003). For the hard phantom, the average of mean SWS measurements across the various imaging methods and depths was 2.14 ± 0.08 m/s for the Acuson S3000 system and 2.07 ± 0.03 m/s Aixplorer system (p>0.05). The coefficients of variation were low (0.5–6.8%), and inter-operator agreement was near-perfect (ICCs ≥0.99). Shear wave imaging method and imaging depth

Medical Ultrasound Imaging.

ERIC Educational Resources Information Center

Hughes, Stephen

2001-01-01

Explains the basic principles of ultrasound using everyday physics. Topics include the generation of ultrasound, basic interactions with material, and the measurement of blood flow using the Doppler effect. (Author/MM)

Application of ultrasound-tagged photons for measurement of amplitude of vibration of tissue caused by ultrasound: theory, simulation, and experiments.

PubMed

Devi, C Usha; Vasu, R M; Sood, A K

2006-01-01

We investigate the modulation of an optical field caused by its interaction with an ultrasound beam in a tissue mimicking phantom. This modulation appears as a modulation in the intensity autocorrelation, which is measured by a photon counting correlator. The factors contributing to the modulation are: 1. amplitude of vibration of the particles of the tissue, 2. refractive index modulation, and 3. absorption coefficient in the region of the tissue intercepted by the ultrasound beam and light. We show in this work that a significant part of the contribution to this modulation comes from displacement of the tissue particles, which in turn is governed by the elastic properties of the tissue. We establish, both through simulations and experiments using an optical elastography phantom, the effects of the elasticity and absorption coefficient variations on the modulation of intensity autocorrelation. In the case where there is no absorption coefficient variation, we suggest that the depth of modulation can be calibrated to measure the displacement of tissue particles that, in turn, can be used to measure the tissue elasticity.

Statistical shape modeling based renal volume measurement using tracked ultrasound

NASA Astrophysics Data System (ADS)

Pai Raikar, Vipul; Kwartowitz, David M.

2017-03-01

Autosomal dominant polycystic kidney disease (ADPKD) is the fourth most common cause of kidney transplant worldwide accounting for 7-10% of all cases. Although ADPKD usually progresses over many decades, accurate risk prediction is an important task.1 Identifying patients with progressive disease is vital to providing new treatments being developed and enable them to enter clinical trials for new therapy. Among other factors, total kidney volume (TKV) is a major biomarker predicting the progression of ADPKD. Consortium for Radiologic Imaging Studies in Polycystic Kidney Disease (CRISP)2 have shown that TKV is an early, and accurate measure of cystic burden and likely growth rate. It is strongly associated with loss of renal function.3 While ultrasound (US) has proven as an excellent tool for diagnosing the disease; monitoring short-term changes using ultrasound has been shown to not be accurate. This is attributed to high operator variability and reproducibility as compared to tomographic modalities such as CT and MR (Gold standard). Ultrasound has emerged as one of the standout modality for intra-procedural imaging and with methods for spatial localization has afforded us the ability to track 2D ultrasound in physical space which it is being used. In addition to this, the vast amount of recorded tomographic data can be used to generate statistical shape models that allow us to extract clinical value from archived image sets. In this work, we aim at improving the prognostic value of US in managing ADPKD by assessing the accuracy of using statistical shape model augmented US data, to predict TKV, with the end goal of monitoring short-term changes.

Consideration on suppression of cancer cell proliferation by ultrasound exposure using sonochemical and biological measurements

NASA Astrophysics Data System (ADS)

Watanabe, A.; Nishimura, H.; Kawashima, N.; Takeuchi, S.

2004-01-01

The suppression methods of cancer cells proliferation using ultrasound exposure are investigated to develop a new minimally invasive cancer treatment method. A stainless steel vibrating plate with a Langevin type transducer is attached to the bottom of a water tank of the ultrasound exposure system used in this study. Ultrasound was irradiated to cancer cells of mouse T lymphoma (EL-4) in a flask. A decreasing tendency of the number of viable cancer cells exposed to ultrasound of 150 kHz and acoustic intensity ISPTP of 750 mW/cm2 was confirmed in the culturing process. Then, the suppression mechanism of cancer cell proliferation by ultrasound exposure was considered through confirmation of apoptosis and necrosis with the exposed cancer cells by electrophoresis and enzyme activity measurements. It was found that the apoptosis was induced on the cancer cells after ultrasound exposure. We confirmed the generation of hydroxyl radical in water in the water tank by ESR device. When the hydroxyl radicals were scavenged by adding ethanol to the culture medium for cancer cells, the apoptosis was not induced and proliferation was not suppressed. Therefore, we found that generation of activated oxygen in the culturing medium by ultrasound exposure was caused to apoptosis induction and suppression of cancer cell proliferation. We will present the results of above consideration in this conference.

Quantitative analysis of fetal facial morphology using 3D ultrasound and statistical shape modeling: a feasibility study.

PubMed

Dall'Asta, Andrea; Schievano, Silvia; Bruse, Jan L; Paramasivam, Gowrishankar; Kaihura, Christine Tita; Dunaway, David; Lees, Christoph C

2017-07-01

The antenatal detection of facial dysmorphism using 3-dimensional ultrasound may raise the suspicion of an underlying genetic condition but infrequently leads to a definitive antenatal diagnosis. Despite advances in array and noninvasive prenatal testing, not all genetic conditions can be ascertained from such testing. The aim of this study was to investigate the feasibility of quantitative assessment of fetal face features using prenatal 3-dimensional ultrasound volumes and statistical shape modeling. STUDY DESIGN: Thirteen normal and 7 abnormal stored 3-dimensional ultrasound fetal face volumes were analyzed, at a median gestation of 29 +4  weeks (25 +0 to 36 +1 ). The 20 3-dimensional surface meshes generated were aligned and served as input for a statistical shape model, which computed the mean 3-dimensional face shape and 3-dimensional shape variations using principal component analysis. Ten shape modes explained more than 90% of the total shape variability in the population. While the first mode accounted for overall size differences, the second highlighted shape feature changes from an overall proportionate toward a more asymmetric face shape with a wide prominent forehead and an undersized, posteriorly positioned chin. Analysis of the Mahalanobis distance in principal component analysis shape space suggested differences between normal and abnormal fetuses (median and interquartile range distance values, 7.31 ± 5.54 for the normal group vs 13.27 ± 9.82 for the abnormal group) (P = .056). This feasibility study demonstrates that objective characterization and quantification of fetal facial morphology is possible from 3-dimensional ultrasound. This technique has the potential to assist in utero diagnosis, particularly of rare conditions in which facial dysmorphology is a feature. Copyright © 2017 Elsevier Inc. All rights reserved.

Noninvasive Diagnosis of Nonalcoholic Fatty Liver Disease and Quantification of Liver Fat Using a New Quantitative Ultrasound Technique.

PubMed

Lin, Steven C; Heba, Elhamy; Wolfson, Tanya; Ang, Brandon; Gamst, Anthony; Han, Aiguo; Erdman, John W; O'Brien, William D; Andre, Michael P; Sirlin, Claude B; Loomba, Rohit

2015-07-01

Liver biopsy analysis is the standard method used to diagnose nonalcoholic fatty liver disease (NAFLD). Advanced magnetic resonance imaging is a noninvasive procedure that can accurately diagnose and quantify steatosis, but is expensive. Conventional ultrasound is more accessible but identifies steatosis with low levels of sensitivity, specificity, and quantitative accuracy, and results vary among technicians. A new quantitative ultrasound (QUS) technique can identify steatosis in animal models. We assessed the accuracy of QUS in the diagnosis and quantification of hepatic steatosis, comparing findings with those from magnetic resonance imaging proton density fat fraction (MRI-PDFF) analysis as a reference. We performed a prospective, cross-sectional analysis of a cohort of adults (N = 204) with NAFLD (MRI-PDFF, ≥5%) and without NAFLD (controls). Subjects underwent MRI-PDFF and QUS analyses of the liver on the same day at the University of California, San Diego, from February 2012 through March 2014. QUS parameters and backscatter coefficient (BSC) values were calculated. Patients were assigned randomly to training (n = 102; mean age, 51 ± 17 y; mean body mass index, 31 ± 7 kg/m(2)) and validation (n = 102; mean age, 49 ± 17 y; body mass index, 30 ± 6 kg/m(2)) groups; 69% of patients in each group had NAFLD. BSC (range, 0.00005-0.25 1/cm-sr) correlated with MRI-PDFF (Spearman ρ = 0.80; P < .0001). In the training group, the BSC analysis identified patients with NAFLD with an area under the curve value of 0.98 (95% confidence interval, 0.95-1.00; P < .0001). The optimal BSC cut-off value identified patients with NAFLD in the training and validation groups with 93% and 87% sensitivity, 97% and 91% specificity, 86% and 76% negative predictive values, and 99% and 95% positive predictive values, respectively. QUS measurements of BSC can accurately diagnose and quantify hepatic steatosis, based on a cross-sectional analysis that used MRI-PDFF as the reference

Added value of semi-quantitative breast-specific gamma imaging in the work-up of suspicious breast lesions compared to mammography, ultrasound and 3-T MRI

PubMed Central

Seymer, A; Keinrath, P; Holzmannhofer, J; Pirich, C; Hergan, K; Meissnitzer, M W

2015-01-01

Objective: To prospectively analyse the diagnostic value of semi-quantitative breast-specific gamma imaging (BSGI) in the work-up of suspicious breast lesions compared with that of mammography (MG), breast ultrasound and MRI of the breast. Methods: Within a 15-month period, 67 patients with 92 breast lesions rated as Category IV or V according to the breast imaging reporting and data system detected with MG and/or ultrasound were included into the study. After the injection of 740–1110 MBq of Technetium-99m (99mTc) SestaMIBI intravenously, scintigrams were obtained in two projections comparable to MG. The BSGI was analysed visually and semi-quantitatively by calculating a relative uptake factor (X). With the exception of two patients with cardiac pacemakers, all patients underwent 3-T breast MRI. Biopsy results were obtained as the reference standard in all patients. Sensitivity, specificity, positive- and negative-predictive values, accuracy and area under the curve were calculated for each modality. Results: Among the 92 lesions, 67 (72.8%) were malignant. 60 of the 67 cancers of any size were detected by BSGI with an overall sensitivity of 90%, only exceeded by ultrasound with a sensitivity of 99%. The sensitivity of BSGI for lesions <1 cm declined significantly to 60%. Overall specificity of ultrasound was only 20%. Specificity, accuracy and positive-predictive value were the highest for BSGI (56%, 80% and 85%, respectively). X was significantly higher for malignant lesions (mean, 4.27) and differed significantly between ductal types (mean, 4.53) and the other histopathological entities (mean, 3.12). Conclusion: Semi-quantitative BSGI with calculation of the relative uptake factor (X) can help to characterize breast lesions. BSGI negativity may obviate the need for biopsy of breast lesions >1 cm with low or intermediate prevalence for malignancy. Advances in knowledge: Compared with morphological imaging modalities, specificity, positive

Measuring the acoustoelectric interaction constant using ultrasound current source density imaging

NASA Astrophysics Data System (ADS)

Li, Qian; Olafsson, Ragnar; Ingram, Pier; Wang, Zhaohui; Witte, Russell

2012-10-01

Ultrasound current source density imaging (UCSDI) exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity, to map electrical conduction in the heart. The conversion efficiency for UCSDI is determined by the AE interaction constant K, a fundamental property of all materials; K directly affects the magnitude of the detected voltage signal in UCSDI. This paper describes a technique for measuring K in biological tissue, and reports its value for the first time in cadaver hearts. A custom chamber was designed and fabricated to control the geometry for estimating K, which was measured in different ionic salt solutions and seven cadaver rabbit hearts. We found K to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart, K was determined to be 0.041±0.012%/MPa, similar to the measurement of K in physiological saline (0.034±0.003%/MPa). This study provides a baseline estimate of K for modeling and experimental studies that involve UCSDI to map cardiac conduction and reentry currents associated with arrhythmias.

Test-retest reliability of 3D ultrasound measurements of the thoracic spine.

PubMed

Fölsch, Christian; Schlögel, Stefanie; Lakemeier, Stefan; Wolf, Udo; Timmesfeld, Nina; Skwara, Adrian

2012-05-01

To explore the reliability of the Zebris CMS 20 ultrasound analysis system with pointer application for measuring end-range flexion, end-range extension, and neutral kyphosis angle of the thoracic spine. The study was performed within the School of Physiotherapy in cooperation with the Orthopedic Department at a University Hospital. The thoracic spines of 28 healthy subjects were measured. Measurements for neutral kyphosis angle, end-range flexion, and end-range extension were taken once at each time point. The bone landmarks were palpated by one examiner and marked with a pointer containing 2 transmitters using a frequency of 40 kHz. A third transmitter was fixed to the pelvis, and 3 microphones were used as receiver. The real angle was calculated by the software. Bland-Altman plots with 95% limits of agreement, intraclass correlations (ICC), standard deviations of mean measurements, and standard error of measurements were used for statistical analyses. The test-retest reliability in this study was measured within a 24-hour interval. Statistical parameters were used to judge reliability. The mean kyphosis angle was 44.8° with a standard deviation of 17.3° at the first measurement and a mean of 45.8° with a standard deviation of 16.2° the following day. The ICC was high at 0.95 for the neutral kyphosis angle, and the Bland-Altman 95% limits of agreement were within clinical acceptable margins. The ICC was 0.71 for end-range flexion and 0.34 for end-range extension, whereas the Bland-Altman 95% limits of agreement were wider than with the static measurement of kyphosis. Compared with static measurements, the analysis of motion with 3-dimensional ultrasound showed an increased standard deviation for test-retest measurements. The test-retest reliability of ultrasound measuring of the neutral kyphosis angle of the thoracic spine was demonstrated within 24 hours. Bland-Altman 95% limits of agreement and the standard deviation of differences did not appear to be

Quantitative three-dimensional transrectal ultrasound (TRUS) for prostate imaging

NASA Astrophysics Data System (ADS)

Pathak, Sayan D.; Aarnink, Rene G.; de la Rosette, Jean J.; Chalana, Vikram; Wijkstra, Hessel; Haynor, David R.; Debruyne, Frans M. J.; Kim, Yongmin

1998-06-01

With the number of men seeking medical care for prostate diseases rising steadily, the need of a fast and accurate prostate boundary detection and volume estimation tool is being increasingly experienced by the clinicians. Currently, these measurements are made manually, which results in a large examination time. A possible solution is to improve the efficiency by automating the boundary detection and volume estimation process with minimal involvement from the human experts. In this paper, we present an algorithm based on SNAKES to detect the boundaries. Our approach is to selectively enhance the contrast along the edges using an algorithm called sticks and integrate it with a SNAKES model. This integrated algorithm requires an initial curve for each ultrasound image to initiate the boundary detection process. We have used different schemes to generate the curves with a varying degree of automation and evaluated its effects on the algorithm performance. After the boundaries are identified, the prostate volume is calculated using planimetric volumetry. We have tested our algorithm on 6 different prostate volumes and compared the performance against the volumes manually measured by 3 experts. With the increase in the user inputs, the algorithm performance improved as expected. The results demonstrate that given an initial contour reasonably close to the prostate boundaries, the algorithm successfully delineates the prostate boundaries in an image, and the resulting volume measurements are in close agreement with those made by the human experts.

Biaxial Mechanical Testing of Posterior Sclera using High-Resolution Ultrasound Speckle Tracking for Strain Measurements

PubMed Central

Cruz-Perez, Benjamin; Tang, Junhua; Morris, Hugh J.; Palko, Joel R.; Pan, Xueliang; Hart, Richard T.; Liu, Jun

2014-01-01

This study aimed to characterize the mechanical responses of the sclera, the white outer coat of the eye, under equal-biaxial loading with unrestricted shear. An ultrasound speckle tracking technique was used to measure tissue deformation through sample thickness, expanding the capabilities of surface strain techniques. Eight porcine scleral samples were tested within 72 hours postmortem. High resolution ultrasound scans of scleral cross-sections along the two loading axes were acquired at 25 consecutive biaxial load levels. An additional repeat of the biaxial loading cycle was performed to measure a third normal strain emulating a strain gauge rosette for calculating the in-plane shear. The repeatability of the strain measurements during identical biaxial ramps was evaluated. A correlation-based ultrasound speckle tracking algorithm was used to compute the displacement field and determine the distributive strains in the sample cross-sections. A Fung type constitutive model including a shear term was used to determine the material constants of each individual specimen by fitting the model parameters to the experimental stress-strain data. A non-linear stress-strain response was observed in all samples. The meridian direction had significantly larger strains than the circumferential direction during equal-biaxial loadings (P’s<0.05). The stiffness along the two directions were also significantly different (P=0.02) but highly correlated (R2=0.8). These results showed that the mechanical properties of the porcine sclera were nonlinear and anisotropic under biaxial loading. This work has also demonstrated the feasibility of using ultrasound speckle tracking for strain measurements during mechanical testing. PMID:24438767

Broadband attenuation measurements of phospholipid-shelled ultrasound contrast agents.

PubMed

Raymond, Jason L; Haworth, Kevin J; Bader, Kenneth B; Radhakrishnan, Kirthi; Griffin, Joseph K; Huang, Shao-Ling; McPherson, David D; Holland, Christy K

2014-02-01

The aim of this study was to characterize the frequency-dependent acoustic attenuation of three phospholipid-shelled ultrasound contrast agents (UCAs): Definity, MicroMarker and echogenic liposomes. A broadband through-transmission technique allowed for measurement over 2 to 25 MHz with a single pair of transducers. Viscoelastic shell parameters of the UCAs were estimated using a linearized model developed by N. de Jong, L. Hoff, T. Skotland and N. Bom (Ultrasonics 1992; 30:95-103). The effect of diluent on the attenuation of these UCA suspensions was evaluated by performing attenuation measurements in 0.5% (w/v) bovine serum albumin and whole blood. Changes in attenuation and shell parameters of the UCAs were investigated at room temperature (25°C) and physiologic temperature (37°C). The attenuation of the UCAs diluted in 0.5% (w/v) bovine serum albumin was found to be identical to the attenuation of UCAs in whole blood. For each UCA, attenuation was higher at 37°C than at 25°C, underscoring the importance of conducting characterization studies at physiologic temperature. Echogenic liposomes exhibited a larger increase in attenuation at 37°C versus 25°C than either Definity or MicroMarker. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Measurement of Mechanical Properties of Soft Tissue with Ultrasound Vibrometry

NASA Astrophysics Data System (ADS)

Nenadich, I.; Bernal, M.; Greenleaf, J. F.

The cardiovascular diseases atherosclerosis, coronary artery disease, hypertension and heart failure have been related to stiffening of vessels and myocardium. Noninvasive measurements of mechanical properties of cardiovascular tissue would facilitate detection and treatment of disease in early stages, thus reducing mortality and possibly reducing cost of treatment. While techniques capable of measuring tissue elasticity have been reported, the knowledge of both elasticity and viscosity is necessary to fully characterize mechanical properties of soft tissues. In this article, we summarize the Shearwave Dispersion Ultrasound Vibrometry (SDUV) method developed by our group and report on advances made in characterizing stiffness of large vessels and myocardium. The method uses radiation forceFadiation force to excite shear waves in soft tissue and pulse echo ultrasound to measure the motion. The speed of propagation of shear waves at different frequencies is used to generate dispersions curves for excised porcine left-ventricular free-wall myocardium and carotid arteries. An antisymmetric Lamb wave model was fitted to the LV myocardium dispersion curves to obtain elasticity and viscosity moduli. The results suggest that the speed of shear wave propagation in four orthogonal directions on the surface of the excised myocardium is similar. These studies show that the SDUV method has potential for clinical application in noninvasive quantification of elasticity and viscosity of vessels and myocardium.

System and method for improving ultrasound image acquisition and replication for repeatable measurements of vascular structures

NASA Technical Reports Server (NTRS)

Selzer, Robert H. (Inventor); Hodis, Howard N. (Inventor)

2006-01-01

High resolution B-mode ultrasound images of the common carotid artery are obtained with an ultrasound transducer using a standardized methodology. Subjects are supine with the head counter-rotated 45 degrees using a head pillow. The jugular vein and carotid artery are located and positioned in a vertical stacked orientation. The transducer is rotated 90 degrees around the centerline of the transverse image of the stacked structure to obtain a longitudinal image while maintaining the vessels in a stacked position. A computerized methodology assists operators to accurately replicate images obtained over several spaced-apart examinations. The methodology utilizes a split-screen display in which the arterial ultrasound image from an earlier examination is displayed on one side of the screen while a real-time live ultrasound image from a current examination is displayed next to the earlier image on the opposite side of the screen. By viewing both images, whether simultaneously or alternately, while manually adjusting the ultrasound transducer, an operator is able to bring into view the real-time image that best matches a selected image from the earlier ultrasound examination. Utilizing this methodology, measurement of vascular dimensions such as carotid arterial IMT and diameter, the coefficient of variation is substantially reduced to values approximating from about 1.0% to about 1.25%. All images contain anatomical landmarks for reproducing probe angulation, including visualization of the carotid bulb, stacking of the jugular vein above the carotid artery, and initial instrumentation settings, used at a baseline measurement are maintained during all follow-up examinations.

[Efficacy and problems of bladder volume measurement using portable three dimensional ultrasound scanning device--in particular, on measuring bladder volume lower than 100ml].

PubMed

Oh-Oka, Hitoshi; Nose, Ryuichiro

2005-09-01

Using a portable three dimensional ultrasound scanning device (The Bladder Scan BVI6100, Diagnostic Ultrasound Corporation), we examined measured values of bladder volume, especially focusing on volume lower than 100 ml. A total of 100 patients (male: 66, female: 34) were enrolled in the study. We made a comparison study between the measured value (the average of three measurements of bladder urine volume after a trial in male and female modes) using BVI6100, and the actual measured value of the sample obtained by urethral catheterization in each patient. We examined the factors which could increase the error rate. We also introduced the effective techniques to reduce measurement errors. The actual measured values in all patients correlated well with the average value of three measurements after a trial in a male mode of the BVI6100. The correlation coefficient was 0.887, the error rate was--4.6 +/- 24.5%, and the average coefficient of variation was 15.2. It was observed that the measurement result using the BVI6100 is influenced by patient side factors (extracted edges between bladder wall and urine, thickened bladder wall, irregular bladder wall, flattened rate of bladder, mistaking prostate for bladder in male, mistaking bladder for uterus in a female mode, etc.) or examiner side factors (angle between BVI and abdominal wall, compatibility between abdominal wall and ultrasound probe, controlling deflection while using probe, etc). When appropriate patients are chosen and proper measurement is performed, BVI6100 provides significantly higher accuracy in determining bladder volume, compared with existing abdominal ultrasound methods. BVI6100 is a convenient and extremely effective device also for the measurement of bladder urine over 100 ml.

Body Mass Normalization for Ultrasound Measurements of Adolescent Lateral Abdominal Muscle Thickness.

PubMed

Linek, Pawel; Saulicz, Edward; Wolny, Tomasz; Myśliwiec, Andrzej

2017-04-01

The purpose of this study was to determine the value of the allometric parameter for ultrasound measurements of the thickness of the oblique external (OE), internal (OI), and transversus abdominis (TrA) muscles in the adolescent population. The allometric parameter is the slope of the linear regression line between the log transformed body mass and log transformed muscle size measurement. The study included 321 adolescents between the ages of 10 and 17, consisting of 160 boys and 161 girls. The participants were recruited from local schools and attended regular school classes at normal grade levels. All individuals with no signs of scoliosis (screening with use of a scoliometer), and no surgical procedures performed on the trunk area were included. A real-time ultrasound B-scanner with a linear array transducer was used to obtain images of the lateral abdominal muscles from both sides of the body. The correlation between body mass and the OE muscle was r = 0.69; the OI muscle r = 0.68; and the TrA muscle r = 0.53 (in all cases, P < .0001). The allometric parameter for the OE was 0.88296; the OI 0.718756; and the TrA 0.60986. Using these parameters, no significant correlations were found between body mass and the allometric-scaled thickness of the lateral abdominal muscles. Significant positive correlations exist between body mass and lateral abdominal muscle thickness assessed by ultrasound imaging. Therefore, it is reasonable to advise that the values of the allometric parameters for OE, OI, and TrA obtained in this study should be used in other studies performed on adolescents. © 2016 by the American Institute of Ultrasound in Medicine.

Gas hydrate property measurements in porous sediments with resonant ultrasound spectroscopy

NASA Astrophysics Data System (ADS)

McGrail, B. P.; Ahmed, S.; Schaef, H. T.; Owen, A. T.; Martin, P. F.; Zhu, T.

2007-05-01

Resonant ultrasound spectroscopy was used to characterize a natural geological core sample obtained from the Mallik 5L-38 gas hydrate research well at high pressure and subambient temperatures. Using deuterated methane gas to form gas hydrate in the core sample, it was discovered that resonance amplitudes are correlated with the fraction of the pore space occupied by the gas hydrate crystals. A pore water freezing model was developed that utilizes the known pore size distribution and pore water chemistry to predict gas hydrate saturation as a function of pressure and temperature. The model showed good agreement with the experimental measurements and demonstrated that pore water chemistry is the most important factor controlling equilibrium gas hydrate saturations in these sediments when gas hydrates are formed artificially in laboratory pressure vessels. With further development, the resonant ultrasound technique can provide a rapid, nondestructive, field portable means of measuring the equilibrium P-T properties and dissociation kinetics of gas hydrates in porous media, determining gas hydrate saturations, and may provide new insights into the nature of gas hydrate formation mechanisms in geologic materials.

Measurement of shear-wave velocity by ultrasound critical-angle reflectometry (UCR).

PubMed

Mehta, S; Antich, P

1997-01-01

There exists a growing body of research that relates the measurement of pressure-wave velocity in bone to different physiological conditions and treatment modalities. The shear-wave velocity has been less studied, although it is necessary for a more complete understanding of the mechanical properties of bone. Ultrasound critical-angle reflectometry (UCR) is a noninvasive and nondestructive technique previously used to measure pressure-wave velocities both in vitro and in vivo. This note describes its application to the measurement of shear-wave velocity in bone, whether directly accessible or covered by soft tissue.

Measurement of shear-wave velocity by ultrasound critical-angle reflectometry (UCR)

NASA Technical Reports Server (NTRS)

Mehta, S.; Antich, P.; Blomqvist, C. G. (Principal Investigator)

1997-01-01

There exists a growing body of research that relates the measurement of pressure-wave velocity in bone to different physiological conditions and treatment modalities. The shear-wave velocity has been less studied, although it is necessary for a more complete understanding of the mechanical properties of bone. Ultrasound critical-angle reflectometry (UCR) is a noninvasive and nondestructive technique previously used to measure pressure-wave velocities both in vitro and in vivo. This note describes its application to the measurement of shear-wave velocity in bone, whether directly accessible or covered by soft tissue.

Breast density measurements using ultrasound tomography for patients undergoing tamoxifen treatment

NASA Astrophysics Data System (ADS)

Sak, Mark; Duric, Neb; Littrup, Peter; Li, Cuiping; Bey-Knight, Lisa; Sherman, Mark; Boyd, Norman; Gierach, Gretchen

2013-03-01

Women with high breast density have an increased risk of developing breast cancer. Women treated with the selective estrogen receptor modulator tamoxifen for estrogen receptor positive breast cancer experience a 50% reduction in risk of contralateral breast cancer and overall reduction of similar magnitude has been identified among high-risk women receiving the drug for prevention. Tamoxifen has been shown to reduce mammographic density, and in the IBIS-1 chemoprevention trial, risk reduction and decline in density were significantly associated. Ultrasound tomography (UST) is an imaging modality that can create tomographic sound speed images of the breast. These sound speed images are useful because breast density is proportional to sound speed. The aim of this work is to examine the relationship between USTmeasured breast density and the use of tamoxifen. So far, preliminary results for a small number of patients have been observed and are promising. Correlations between the UST-measured density and mammographic density are strong and positive, while relationships between UST density with some patient specific risk factors behave as expected. Initial results of UST examinations of tamoxifen treated patients show that approximately 45% of the patients have a decrease in density in the contralateral breast after only several months of treatment. The true effect of tamoxifen on UST-measured density cannot yet be fully determined until more data are collected. However, these promising results suggest that UST can be used to reliably assess quantitative changes in breast density over short intervals and therefore suggest that UST may enable rapid assessment of density changes associated with therapeutic and preventative interventions.

In-vivo investigation of material quality of bone tissue by measuring apparent phalangeal ultrasound transmission velocity.

PubMed

Kann, P; Schulz, U; Klaus, D; Piepkorn, B; Beyer, J

1995-01-01

The square of ultrasound transmission velocity in a material is related to the modulus of elasticity, which is known to be an indicator of stability in bone. The aim of our study was to use ultrasound transmission velocity to obtain information about the material properties of bone tissue, keeping other factors possibly influencing ultrasound transmission as constant as possible. Apparent phalangeal ultrasound transmission velocity (APU) measured in 54 isolated, fresh pig phalanges was shown to be independent of bone mineral density (BMD) measured by SPA. Fastest sound transmission led exclusively through cortical bone so that intertrabecular connectivity in spongious bone could not influence the result. In humans APU was measured in the mediolateral direction at the midphalanx of the middle finger. In 53 healthy subjects (15-81 years old; 27 women, 26 men), there was a decrease of APU with age (r = -0.30, p < 0.05). Further, when comparing the results of both hands intraindividually almost identical values indicated constant intraindividual architecture of bone at this location. There was no evidence for a relation of APU to physical load comparing dominant and nondominant hand and relating the results to subjectively estimated physical load. In a second group of 43 perimenopausal women (47-60 years old), APU, which again decreased with age (r = -0.33, p < 0.05), was found not to be correlated to BMD measured by SPA at the distal forearm (cortical bone).(ABSTRACT TRUNCATED AT 250 WORDS)

Automatic segmentation and measurements of gestational sac using static B-mode ultrasound images

NASA Astrophysics Data System (ADS)

Ibrahim, Dheyaa Ahmed; Al-Assam, Hisham; Du, Hongbo; Farren, Jessica; Al-karawi, Dhurgham; Bourne, Tom; Jassim, Sabah

2016-05-01

Ultrasound imagery has been widely used for medical diagnoses. Ultrasound scanning is safe and non-invasive, and hence used throughout pregnancy for monitoring growth. In the first trimester, an important measurement is that of the Gestation Sac (GS). The task of measuring the GS size from an ultrasound image is done manually by a Gynecologist. This paper presents a new approach to automatically segment a GS from a static B-mode image by exploiting its geometric features for early identification of miscarriage cases. To accurately locate the GS in the image, the proposed solution uses wavelet transform to suppress the speckle noise by eliminating the high-frequency sub-bands and prepare an enhanced image. This is followed by a segmentation step that isolates the GS through the several stages. First, the mean value is used as a threshold to binarise the image, followed by filtering unwanted objects based on their circularity, size and mean of greyscale. The mean value of each object is then used to further select candidate objects. A Region Growing technique is applied as a post-processing to finally identify the GS. We evaluated the effectiveness of the proposed solution by firstly comparing the automatic size measurements of the segmented GS against the manual measurements, and then integrating the proposed segmentation solution into a classification framework for identifying miscarriage cases and pregnancy of unknown viability (PUV). Both test results demonstrate that the proposed method is effective in segmentation the GS and classifying the outcomes with high level accuracy (sensitivity (miscarriage) of 100% and specificity (PUV) of 99.87%).

Carotid intima-media thickness: ultrasound measurement, prognostic value and role in clinical practice.

PubMed

Nair, Satheesh Balakrishnan; Malik, Rayaz; Khattar, Rajdeep S

2012-12-01

Ultrasound measurement of carotid intima-media thickness (IMT) has become a valuable tool for detecting and monitoring progression of atherosclerosis and recently published recommendations provide guidance for proper standardisation of these measurements. Important determinants of carotid IMT include age, gender, systolic blood pressure, diabetes mellitus and serum cholesterol levels. Many studies have shown carotid IMT to correlate with the severity of coronary atherosclerosis assessed by CT coronary calcification scores, coronary angiography and intravascular ultrasound. Consistent with its correlation with cardiovascular risk factors and coronary artery disease, a meta-analysis of large observational studies has shown carotid IMT to be a strong predictor of future cardiovascular events. Moreover, in patients with established coronary artery disease a reduction in carotid IMT has been shown to translate into a reduction in future cardiovascular events. Consensus statements now also recommend carotid IMT measurements to further refine the prognostic assessment of patients traditionally considered to be at an intermediate risk of cardiovascular disease.

Normative calcaneal quantitative ultrasound data for the indigenous Shuar and non-Shuar Colonos of the Ecuadorian Amazon.

PubMed

Madimenos, Felicia C; Snodgrass, J Josh; Blackwell, Aaron D; Liebert, Melissa A; Cepon, Tara J; Sugiyama, Lawrence S

2011-01-01

Minimal data on bone mineral density changes are available from populations in developing countries. Using calcaneal quantitative ultrasound (QUS) techniques, the current study contributes to remedying this gap in the literature by establishing a normative data set on the indigenous Shuar and non-Shuar Colonos of the Ecuadorian Amazon. The paucity of bone mineral density (BMD) data from populations in developing countries partially reflects the lack of diagnostic resources in these areas. Portable QUS techniques now enable researchers to collect bone health data in remote field-based settings and to contribute normative data from developing regions. The main objective of this study is to establish normative QUS data for two Ecuadorian Amazonian populations-the indigenous Shuar and non-Shuar Colonos. The effects of ethnic group, sex, age, and body size on QUS parameters are also considered. A study cohort consisting of 227 Shuar and 261 Colonos (15-91 years old) were recruited from several small rural Ecuadorian communities in the Upano River Valley. Calcaneal QUS parameters were collected on the right heel of each participant using a Sahara bone sonometer. Three ultrasound generated parameters were employed: broadband ultrasound attenuation (BUA), speed of sound (SOS), and calculated heel BMD (hBMD). In both populations and sexes, all QUS values were progressively lower with advancing age. Shuar have significantly higher QUS values than Colonos, with most pronounced differences found between pre-menopausal Shuar and Colono females. Multiple regression analyses show that age is a key predictor of QUS while weight alone is a less consistent determinant. Both Shuar males and females display comparatively greater QUS parameters than other reference populations. These normative data for three calcaneal QUS parameters will be useful for predicting fracture risk and determining diagnostic QUS criteria of osteoporosis in non-industrialized populations in South America and

Quantitative validation of an air-coupled ultrasonic probe model by Interferometric laser tomography

NASA Astrophysics Data System (ADS)

Revel, G. M.; Pandarese, G.; Cavuto, A.

2012-06-01

The present paper describes the quantitative validation of a finite element (FE) model of the ultrasound beam generated by an air coupled non-contact ultrasound transducer. The model boundary conditions are given by vibration velocities measured by laser vibrometry on the probe membrane. The proposed validation method is based on the comparison between the simulated 3D pressure field and the pressure data measured with interferometric laser tomography technique. The model details and the experimental techniques are described in paper. The analysis of results shows the effectiveness of the proposed approach and the possibility to quantitatively assess and predict the generated acoustic pressure field, with maximum discrepancies in the order of 20% due to uncertainty effects. This step is important for determining in complex problems the real applicability of air-coupled probes and for the simulation of the whole inspection procedure, also when the component is designed, so as to virtually verify its inspectability.

Characteristics and Echogenicity of Clinical Ultrasound Contrast Agents: An In Vitro and In Vivo Comparison Study.

PubMed

Hyvelin, Jean-Marc; Gaud, Emmanuel; Costa, Maria; Helbert, Alexandre; Bussat, Philippe; Bettinger, Thierry; Frinking, Peter

2017-05-01

To compare physicochemical characteristics and in vitro and in vivo contrast-enhanced ultrasound imaging performance of 3 commercially available ultrasound contrast agents: SonoVue (Bracco Imaging SpA, Colleretto Giacosa, Italy; also marketed as Lumason in the USA), Definity (Lantheus Medical Imaging, North Billerica, MA) and Optison (GE Healthcare AS, Oslo, Norway). Physicochemical characteristics were measured with a Multisizer Coulter Counter (Beckman Coulter, Fullerton, CA). Two ultrasound systems (Aplio 500; Toshiba Medical Systems Corp, Tochigi-ken, Japan; and Logiq E9; GE Healthcare, Little Chalfont, England) were used with different transducers. Contrast enhancement was measured in vitro by dose-ranging measurements using a custom-built beaker setup; in vivo imaging performances were compared in pigs (heart and liver) and rabbits (liver). Quantitative analyses were performed with VueBox quantification software (Bracco Suisse SA, Plan-les-Ouates, Switzerland). Measured physicochemical characteristics were in agreement with those provided by the manufacturers. In vitro data demonstrated that the performance of SonoVue was similar to or better than that of Definity but superior to Optison (normalized scattered power 2- to 10-fold higher with SonoVue). Similar results were obtained in vivo, although the duration of enhancement in the pig heart was longer for SonoVue compared to Definity, and quantitative analysis revealed higher enhancement for SonoVue (1.5-fold increase). For liver imaging, SonoVue and Definity showed similar contrast enhancement and duration of enhancement, but compared to Optison, both peak enhancement and duration of enhancement were superior for SonoVue (up to 2-fold increase). Imaging performance of SonoVue was similar to or slightly better than that of Definity, but it was superior to Optison for the conditions used in this study. © 2017 by the American Institute of Ultrasound in Medicine.

A Multidimensional Investigation of Children's /r/ Productions: Perceptual, Ultrasound, and Acoustic Measures

ERIC Educational Resources Information Center

Klein, Harriet B.; McAllister Byun, Tara; Davidson, Lisa; Grigos, Maria I.

2013-01-01

Purpose: This study explored relationships among perceptual, ultrasound, and acoustic measurements of children's correct and misarticulated /r/ sounds. Longitudinal data documenting changes across these parameters were collected from 2 children who acquired /r/ over a period of intervention and were compared with data from children with typical…

Nonlocal means-based speckle filtering for ultrasound images

PubMed Central

Coupé, Pierrick; Hellier, Pierre; Kervrann, Charles; Barillot, Christian

2009-01-01

In image processing, restoration is expected to improve the qualitative inspection of the image and the performance of quantitative image analysis techniques. In this paper, an adaptation of the Non Local (NL-) means filter is proposed for speckle reduction in ultrasound (US) images. Originally developed for additive white Gaussian noise, we propose to use a Bayesian framework to derive a NL-means filter adapted to a relevant ultrasound noise model. Quantitative results on synthetic data show the performances of the proposed method compared to well-established and state-of-the-art methods. Results on real images demonstrate that the proposed method is able to preserve accurately edges and structural details of the image. PMID:19482578

Quantitative Imaging of Young's Modulus of Soft Tissues from Ultrasound Water Jet Indentation: A Finite Element Study

PubMed Central

Lu, Min-Hua; Mao, Rui; Lu, Yin; Liu, Zheng; Wang, Tian-Fu; Chen, Si-Ping

2012-01-01

Indentation testing is a widely used approach to evaluate mechanical characteristics of soft tissues quantitatively. Young's modulus of soft tissue can be calculated from the force-deformation data with known tissue thickness and Poisson's ratio using Hayes' equation. Our group previously developed a noncontact indentation system using a water jet as a soft indenter as well as the coupling medium for the propagation of high-frequency ultrasound. The novel system has shown its ability to detect the early degeneration of articular cartilage. However, there is still lack of a quantitative method to extract the intrinsic mechanical properties of soft tissue from water jet indentation. The purpose of this study is to investigate the relationship between the loading-unloading curves and the mechanical properties of soft tissues to provide an imaging technique of tissue mechanical properties. A 3D finite element model of water jet indentation was developed with consideration of finite deformation effect. An improved Hayes' equation has been derived by introducing a new scaling factor which is dependent on Poisson's ratios v, aspect ratio a/h (the radius of the indenter/the thickness of the test tissue), and deformation ratio d/h. With this model, the Young's modulus of soft tissue can be quantitatively evaluated and imaged with the error no more than 2%. PMID:22927890

The measurement of medial knee gap width using ultrasound.

PubMed

Slane, Laura C; Slane, Josh A; Scheys, Lennart

2017-08-01

Medial knee instability is a key clinical parameter for assessing ligament injury and arthroplasty success, but current methods for measuring stability are typically either qualitative or involve ionizing radiation. The purpose of this study was to perform a preliminary analysis of whether ultrasound (US) could be used as an alternate approach for quantifying medial instability by comparing an US method with an approach mimicking the current gold standard fluoroscopy method. US data from the medial knee were collected, while cadaveric lower limbs (n = 8) were loaded in valgus (10 Nm). During post-processing, the US gap width was measured by identifying the medial edges of the femur and tibia and computing the gap width between these points. For comparison, mimicked fluoroscopy (mFluoro) images were created from specimen-specific bone models, developed from segmented CT scans, and from kinematic data collected during testing. Then, gap width was measured in the mFluoro images based on two different published approaches with gap width measured either at the most medial or at the most distal aspect of the femur. Gap width increased significantly with loading (p < 0.001), and there were no significant differences between the US method (unloaded: 8.7 ± 2.4 mm, loaded: 10.7 ± 2.2 mm) and the mFluoro method that measured gap width at the medial femur. In terms of the change in gap width with load, no correlation with the change in abduction angle was observed, with no correlation between the various methods. Inter-rater reliability for the US method was high (0.899-0.952). Ultrasound shows promise as a suitable alternative for quantifying medial instability without radiation exposure. However, the outstanding limitations of existing approaches and lack of true ground-truth data require that further validation work is necessary to better understand the clinical viability of an US approach for measuring medial knee gap width.

Reliability of measuring sciatic and tibial nerve movement with diagnostic ultrasound during a neural mobilisation technique.

PubMed

Ellis, Richard; Hing, Wayne; Dilley, Andrew; McNair, Peter

2008-08-01

Diagnostic ultrasound provides a technique whereby real-time, in vivo analysis of peripheral nerve movement is possible. This study measured sciatic nerve movement during a "slider" neural mobilisation technique (ankle dorsiflexion/plantar flexion and cervical extension/flexion). Transverse and longitudinal movement was assessed from still ultrasound images and video sequences by using frame-by-frame cross-correlation software. Sciatic nerve movement was recorded in the transverse and longitudinal planes. For transverse movement, at the posterior midthigh (PMT) the mean value of lateral sciatic nerve movement was 3.54 mm (standard error of measurement [SEM] +/- 1.18 mm) compared with anterior-posterior/vertical (AP) movement of 1.61 mm (SEM +/- 0.78 mm). At the popliteal crease (PC) scanning location, lateral movement was 6.62 mm (SEM +/- 1.10 mm) compared with AP movement of 3.26 mm (SEM +/- 0.99 mm). Mean longitudinal sciatic nerve movement at the PMT was 3.47 mm (SEM +/- 0.79 mm; n = 27) compared with the PC of 5.22 mm (SEM +/- 0.05 mm; n = 3). The reliability of ultrasound measurement of transverse sciatic nerve movement was fair to excellent (Intraclass correlation coefficient [ICC] = 0.39-0.76) compared with excellent (ICC = 0.75) for analysis of longitudinal movement. Diagnostic ultrasound presents a reliable, noninvasive, real-time, in vivo method for analysis of sciatic nerve movement.

A New Ultrasound Pulser Technique for Wide Range Measurements

NASA Astrophysics Data System (ADS)

Salim, M. S.; Abd Malek, M. F.; Noaman, N. M.; Sabri, Naseer; Mohamed, Latifah; Juni, K. M.

2013-04-01

The objective of this research was to design and implement a new ultrasonic pulse-power-decay technique that transmits multiple ultrasound pulses through slurry to determine the lowest concentration that can provide an accurate attenuation measurement. A wide measurement range is obtained using the pulsed-power-decay transmission technique, and regardless of the material used to construct the container. A signal in the receiver transducer provides the attenuation measurements, for each echo, a fast Fourier transform (FFT) of the appropriate signal was obtained and compared with the water signals to yield the attenuation as a function of frequency. The data show the feasibility of measuring a kaolin concentration of 5% wt. When using a commercial pulser with the same device setting, no detectable echo was observed. Therefore, new technique measurements may prove useful in detecting solid content in liquid. This study demonstrated that the proposed pulsed-power transmission technique is promising for evaluating low concentrations of solids in fluids and for measuring sedimentation in solid-liquid systems.

Investigation of dental samples using a 35MHz focussed ultrasound piezocomposite transducer.

PubMed

Hughes, D A; Girkin, J M; Poland, S; Longbottom, C; Button, T W; Elgoyhen, J; Hughes, H; Meggs, C; Cochran, S

2009-02-01

Dental erosion and decay are increasingly prevalent but as yet there is no quantitative monitoring tool. Such a tool would allow earlier diagnosis and treatment and ultimately the prevention of more serious disease and pain. Despite ultrasound having been demonstrated as a method of probing the internal structures of teeth more than 40 years ago, development of a clinical tool has been slow. The aim of the study reported here was to investigate the use of a novel high frequency ultrasound transducer and validate it using a known dental technique. A tooth extracted for clinical reasons was sectioned to provide a sample that contained an enamel and dentine layer such that the enamel-dentine junction (EDJ) was of a varying depth. The sample was then submerged in water and a B-scan recorded using a custom-designed piezocomposite ultrasound transducer with a centre frequency of 35 MHz and a -6 dB bandwidth of 24 MHz. The transducer has an axial resolution of 180 microm and a spatial resolution of 110 microm, a significant advance on previous work using lower frequencies. The depth of the EDJ was measured from the resulting data set and compared to measurements from the sequential grinding and imaging (SGI) method. The B-scan showed that the EDJ was of varying depth. Subsequently, the EDJ measurements were found to have a correlation of 0.89 (p<0.01) against the SGI measurements. The results indicate that high frequency ultrasound is capable of measuring enamel thickness to an accuracy of within 10% of the total enamel thickness, whereas currently there is no clinical tool available to measure enamel thickness.

Sonophoresis Using Ultrasound Contrast Agents: Dependence on Concentration.

PubMed

Park, Donghee; Song, Gillsoo; Jo, Yongjun; Won, Jongho; Son, Taeyoon; Cha, Ohrum; Kim, Jinho; Jung, Byungjo; Park, Hyunjin; Kim, Chul-Woo; Seo, Jongbum

2016-01-01

Sonophoresis can increase skin permeability to various drugs in transdermal drug delivery. Cavitation is recognized as the predominant mechanism of sonophoresis. Recently, a new logical approach to enhance the efficiency of transdermal drug delivery was tried. It is to utilize the engineered microbubble and its resonant frequency for increase of cavitation activity. Actively-induced cavitation with low-intensity ultrasound (less than ~1 MPa) causes disordering of the lipid bilayers and the formation of aqueous channels by stable cavitation which indicates a continuous oscillation of bubbles. Furthermore, the mutual interactions of microbubble determined by concentration of added bubble are also thought to be an important factor for activity of stable cavitation, even in different characteristics of drug. In the present study, we addressed the dependence of ultrasound contrast agent concentration using two types of drug on the efficiency of transdermal drug delivery. Two types of experiment were designed to quantitatively evaluate the efficiency of transdermal drug delivery according to ultrasound contrast agent concentration. First, an experiment of optical clearing using a tissue optical clearing agent was designed to assess the efficiency of sonophoresis with ultrasound contrast agents. Second, a Franz diffusion cell with ferulic acid was used to quantitatively determine the amount of drug delivered to the skin sample by sonophoresis with ultrasound contrast agents. The maximum enhancement ratio of sonophoresis with a concentration of 1:1,000 was approximately 3.1 times greater than that in the ultrasound group without ultrasound contrast agent and approximately 7.5 times greater than that in the control group. These results support our hypothesis that sonophoresis becomes more effective in transdermal drug delivery due to the presence of engineered bubbles, and that the efficiency of transdermal drug delivery using sonophoresis with microbubbles depends on the

Two-dimensional Shear Wave Elastography on Conventional Ultrasound Scanners with Time Aligned Sequential Tracking (TAST) and Comb-push Ultrasound Shear Elastography (CUSE)

PubMed Central

Song, Pengfei; Macdonald, Michael C.; Behler, Russell H.; Lanning, Justin D.; Wang, Michael H.; Urban, Matthew W.; Manduca, Armando; Zhao, Heng; Callstrom, Matthew R.; Alizad, Azra; Greenleaf, James F.; Chen, Shigao

2014-01-01

Two-dimensional (2D) shear wave elastography presents 2D quantitative shear elasticity maps of tissue, which are clinically useful for both focal lesion detection and diffuse disease diagnosis. Realization of 2D shear wave elastography on conventional ultrasound scanners, however, is challenging due to the low tracking pulse-repetition-frequency (PRF) of these systems. While some clinical and research platforms support software beamforming and plane wave imaging with high PRF, the majority of current clinical ultrasound systems do not have the software beamforming capability, which presents a critical challenge for translating the 2D shear wave elastography technique from laboratory to clinical scanners. To address this challenge, this paper presents a Time Aligned Sequential Tracking (TAST) method for shear wave tracking on conventional ultrasound scanners. TAST takes advantage of the parallel beamforming capability of conventional systems and realizes high PRF shear wave tracking by sequentially firing tracking vectors and aligning shear wave data in the temporal direction. The Comb-push Ultrasound Shear Elastography (CUSE) technique was used to simultaneously produce multiple shear wave sources within the field-of-view (FOV) to enhance shear wave signal-to-noise-ratio (SNR) and facilitate robust reconstructions of 2D elasticity maps. TAST and CUSE were realized on a conventional ultrasound scanner (the General Electric LOGIQ E9). A phantom study showed that the shear wave speed measurements from the LOGIQ E9 were in good agreement to the values measured from other 2D shear wave imaging technologies. An inclusion phantom study showed that the LOGIQ E9 had comparable performance to the Aixplorer (Supersonic Imagine) in terms of bias and precision in measuring different sized inclusions. Finally, in vivo case analysis of a breast with a malignant mass, and a liver from a healthy subject demonstrated the feasibility of using the LOGIQ E9 for in vivo 2D shear wave

Effect of Heat Generation of Ultrasound Transducer on Ultrasonic Power Measured by Calorimetric Method

NASA Astrophysics Data System (ADS)

Uchida, Takeyoshi; Kikuchi, Tsuneo

2013-07-01

Ultrasonic power is one of the key quantities closely related to the safety of medical ultrasonic equipment. An ultrasonic power standard is required for establishment of safety. Generally, an ultrasonic power standard below approximately 20 W is established by the radiation force balance (RFB) method as the most accurate measurement method. However, RFB is not suitable for high ultrasonic power because of thermal damage to the absorbing target. Consequently, an alternative method to RFB is required. We have been developing a measurement technique for high ultrasonic power by the calorimetric method. In this study, we examined the effect of heat generation of an ultrasound transducer on ultrasonic power measured by the calorimetric method. As a result, an excessively high ultrasonic power was measured owing to the effect of heat generation from internal loss in the transducer. A reference ultrasound transducer with low heat generation is required for a high ultrasonic power standard established by the calorimetric method.

Brazilian Pediatric Reference Data for Quantitative Ultrasound of Phalanges According to Gender, Age, Height and Weight

PubMed Central

de Carvalho, Wellington Roberto Gomes; de Moraes, Anderson Marques; Roman, Everton Paulo; Santos, Keila Donassolo; Medaets, Pedro Augusto Rodrigues; Veiga-Junior, Nélio Neves; Coelho, Adrielle Caroline Lace de Moraes; Krahenbühl, Tathyane; Sewaybricker, Leticia Esposito; Barros-Filho, Antonio de Azevedo; Morcillo, Andre Moreno; Guerra-Júnior, Gil

2015-01-01

Aims To establish normative data for phalangeal quantitative ultrasound (QUS) measures in Brazilian students. Methods The sample was composed of 6870 students (3688 females and 3182 males), aged 6 to 17 years. The bone status parameter, Amplitude Dependent Speed of Sound (AD-SoS) was assessed by QUS of the phalanges using DBM Sonic BP (IGEA, Carpi, Italy) equipment. Skin color was obtained by self-evaluation. The LMS method was used to derive smoothed percentiles reference charts for AD-SoS according to sex, age, height and weight and to generate the L, M, and S parameters. Results Girls showed higher AD-SoS values than boys in the age groups 7–16 (p<0.001). There were no differences on AD-SoS Z-scores according to skin color. In both sexes, the obese group showed lower values of AD-SoS Z-scores compared with subjects classified as thin or normal weight. Age (r2 = 0.48) and height (r2 = 0.35) were independent predictors of AD-SoS in females and males, respectively. Conclusion AD-SoS values in Brazilian children and adolescents were influenced by sex, age and weight status, but not by skin color. Our normative data could be used for monitoring AD-SoS in children or adolescents aged 6–17 years. PMID:26043082

Temperature measurement by thermal strain imaging with diagnostic power ultrasound, with potential for thermal index determination.

PubMed

Liang, Hai-Dong; Zhou, Li-Xia; Wells, Peter N T; Halliwell, Michael

2009-05-01

Over the years, there has been a substantial increase in acoustic exposure in diagnostic ultrasound as new imaging modalities with higher intensities and frame rates have been introduced; and more electronic components have been packed into the probe head, so that there is a tendency for it to become hotter. With respect to potential thermal effects, including those which may be hazardous occurring during ultrasound scanning, there is a correspondingly growing need for in vivo techniques to guide the operator as to the actual temperature rise occurring in the examined tissues. Therefore, an in vivo temperature estimator would be of considerable practical value. The commonly-used method of tissue thermal index (TI) measurement with a hydrophone in water could underestimate the actual value of TI (in one report by as much as 2.9 times). To obtain meaningful results, it is necessary to map the temperature elevation in 2-D (or 3-D) space. We present methodology, results and validation of a 2-D spatial and temporal thermal strain ultrasound temperature estimation technique in phantoms, and its apparently novel application in tracking the evolution of heat deposition at diagnostic exposure levels. The same ultrasound probe is used for both transmission and reception. The displacement and thermal strain estimation methods are similar to those used in high-intensity focused ultrasound thermal monitoring. The use of radiofrequency signals permits the application of cross correlation as a similarity measurement for tracking feature displacement. The displacement is used to calculate the thermal strain directly related to the temperature rise. Good agreement was observed between the temperature rise and the ultrasound power and scan duration. Thermal strain up to 1.4% was observed during 4000-s scan. Based on the results obtained for the temperature range studied in this work, the technique demonstrates potential for applicability in phantom (and possibly in vivo tissue

Efficiency of quantitative echogenicity for investigating supraspinatus tendinopathy by the gray-level histogram of two ultrasound devices.

PubMed

Hsu, Jiun-Cheng; Chen, Po-Han; Huang, Kuo-Chin; Tsai, Yao-Hung; Hsu, Wei-Hsiu

2017-10-01

The gray-level histogram of ultrasound is a promising tool for scanning the hypoechogenic appearance of supraspinatus tendinopathy, and the aim of this study was to test the hypothesis that the gray-level value of the supraspinatus tendon in the painful shoulder has a lower value on B-mode images even though in different ultrasound devices. Sixty-seven patients who had unilateral shoulder pain with rotator cuff tendinopathy underwent bilateral shoulder ultrasonography, and we compared the mean gray-level values of painful shoulders and contralateral shoulders without any pain in each patient using two ultrasound devices. The echogenicity ratio (symptomatic/asymptomatic side) of two ultrasound devices was compared. A significant difference existed between the symptomatic shoulder and contralateral asymptomatic shoulder (p < 0.001) on the mean gray-level value measurements of each device. The symptomatic-to-asymptomatic tendon echogenicity ratio of device A was 0.919 ± 0.090 in the transverse plane and 0.937 ± 0.081 in the longitudinal plane, and the echogenicity ratio of device B was 0.899 ± 0.113 in the transverse plane and 0.940 ± 0.113 in the longitudinal plane. The decline of the mean gray-level value and the echogenicity ratio of the supraspinatus tendon in the painful shoulder may be utilized as a useful sonographic reference of unilateral rotator cuff lesions. Diagnostic level III.

Quantitative Shear Wave Velocity Measurement on Acoustic Radiation Force Impulse Elastography for Differential Diagnosis between Benign and Malignant Thyroid Nodules: A Meta-analysis.

PubMed

Liu, Bo-Ji; Li, Dan-Dan; Xu, Hui-Xiong; Guo, Le-Hang; Zhang, Yi-Feng; Xu, Jun-Mei; Liu, Chang; Liu, Lin-Na; Li, Xiao-Long; Xu, Xiao-Hong; Qu, Shen; Xing, Mingzhao

2015-12-01

The aim of this study was to evaluate the diagnostic performance of quantitative shear wave velocity (SWV) measurement on acoustic radiation force impulse (ARFI) elastography for differentiation between benign and malignant thyroid nodules using meta-analysis. The databases of PubMed and the Web of Science were searched. Studies published in English on assessment of the sensitivity and specificity of ARFI elastography for the differentiation of thyroid nodules were collected. The quantitative measurement of ARFI elastography was evaluated by SWV (m/s). Meta-Disc Version 1.4 software was used to describe and calculate the sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio and summary receiver operating characteristic curves. We analyzed a total of 13 studies, which included 1,854 thyroid nodules (including 1,339 benign nodules and 515 malignant nodules) from 1,641 patients. The summary sensitivity and specificity for differential diagnosis between benign and malignant thyroid nodules by SWV were 0.81 (95% confidence interval [CI]: 0.77-0.84) and 0.84 (95% CI: 0.81-0.86), respectively. The pooled positive and negative likelihood ratios were 5.21 (95% CI: 3.56-7.62) and 0.23 (95% CI: 0.17-0.32), respectively. The pooled diagnostic odds ratio was 27.53 (95% CI: 14.58-52.01), and the area under the summary receiver operating characteristic curve was 0.91 (Q* = 0.84). In conclusion, SWV measurement on ARFI elastography has high sensitivity and specificity for differential diagnosis between benign and malignant thyroid nodules and can be used in combination with conventional ultrasound. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Dynamic Contrast-Enhanced Ultrasound Identifies Microcirculatory Alterations in Sepsis-Induced Acute Kidney Injury.

PubMed

Lima, Alexandre; van Rooij, Tom; Ergin, Bulent; Sorelli, Michele; Ince, Yasin; Specht, Patricia A C; Mik, Egbert G; Bocchi, Leonardo; Kooiman, Klazina; de Jong, Nico; Ince, Can

2018-05-15

We developed quantitative methods to analyze microbubble kinetics based on renal contrast-enhanced ultrasound imaging combined with measurements of sublingual microcirculation on a fixed area to quantify early microvascular alterations in sepsis-induced acute kidney injury. Prospective controlled animal experiment study. Hospital-affiliated animal research institution. Fifteen female pigs. The animals were instrumented with a renal artery flow probe after surgically exposing the kidney. Nine animals were given IV infusion of lipopolysaccharide to induce septic shock, and six were used as controls. Contrast-enhanced ultrasound imaging was performed on the kidney before, during, and after having induced shock. Sublingual microcirculation was measured continuously using the Cytocam on the same spot. Contrast-enhanced ultrasound effectively allowed us to develop new analytical methods to measure dynamic variations in renal microvascular perfusion during shock and resuscitation. Renal microvascular hypoperfusion was quantified by decreased peak enhancement and an increased ratio of the final plateau intensity to peak enhancement. Reduced intrarenal blood flow could be estimated by measuring the microbubble transit times between the interlobar arteries and capillary vessels in the renal cortex. Sublingual microcirculation measured using the Cytocam in a fixed area showed decreased functional capillary density associated with plugged sublingual capillary vessels that persisted during and after fluid resuscitation. In our lipopolysaccharide model, with resuscitation targeted at blood pressure, the contrast-enhanced ultrasound imaging can identify renal microvascular alterations by showing prolonged contrast enhancement in microcirculation during shock, worsened by resuscitation with fluids. Concomitant analysis of sublingual microcirculation mirrored those observed in the renal microcirculation.

Anthropomorphic cardiac ultrasound phantom.

PubMed

Smith, S W; Rinaldi, J E

1989-10-01

A new phantom is described which simulates the human cardiac anatomy for applications in ultrasound imaging, ultrasound Doppler, and color-flow Doppler imaging. The phantom consists of a polymer left ventricle which includes a prosthetic mitral and aortic valve and is connected to a mock circulatory loop. Aerated tap water serves as a blood simulating fluid and ultrasound contrast medium within the circulatory loop. The left ventricle is housed in a Lexan ultrasound visualization chamber which includes ultrasound viewing ports and acoustic absorbers. A piston pump connected to the visualization chamber by a single port pumps degassed water within the chamber which in turn pumps the left ventricle. Real-time ultrasound images and Doppler studies measure flow patterns through the valves and within the left ventricle.

Automated kidney morphology measurements from ultrasound images using texture and edge analysis

NASA Astrophysics Data System (ADS)

Ravishankar, Hariharan; Annangi, Pavan; Washburn, Michael; Lanning, Justin

2016-04-01

In a typical ultrasound scan, a sonographer measures Kidney morphology to assess renal abnormalities. Kidney morphology can also help to discriminate between chronic and acute kidney failure. The caliper placements and volume measurements are often time consuming and an automated solution will help to improve accuracy, repeatability and throughput. In this work, we developed an automated Kidney morphology measurement solution from long axis Ultrasound scans. Automated kidney segmentation is challenging due to wide variability in kidney shape, size, weak contrast of the kidney boundaries and presence of strong edges like diaphragm, fat layers. To address the challenges and be able to accurately localize and detect kidney regions, we present a two-step algorithm that makes use of edge and texture information in combination with anatomical cues. First, we use an edge analysis technique to localize kidney region by matching the edge map with predefined templates. To accurately estimate the kidney morphology, we use textural information in a machine learning algorithm framework using Haar features and Gradient boosting classifier. We have tested the algorithm on 45 unseen cases and the performance against ground truth is measured by computing Dice overlap, % error in major and minor axis of kidney. The algorithm shows successful performance on 80% cases.

Breast ultrasound tomography with two parallel transducer arrays: preliminary clinical results

NASA Astrophysics Data System (ADS)

Huang, Lianjie; Shin, Junseob; Chen, Ting; Lin, Youzuo; Intrator, Miranda; Hanson, Kenneth; Epstein, Katherine; Sandoval, Daniel; Williamson, Michael

2015-03-01

Ultrasound tomography has great potential to provide quantitative estimations of physical properties of breast tumors for accurate characterization of breast cancer. We design and manufacture a new synthetic-aperture breast ultrasound tomography system with two parallel transducer arrays. The distance of these two transducer arrays is adjustable for scanning breasts with different sizes. The ultrasound transducer arrays are translated vertically to scan the entire breast slice by slice and acquires ultrasound transmission and reflection data for whole-breast ultrasound imaging and tomographic reconstructions. We use the system to acquire patient data at the University of New Mexico Hospital for clinical studies. We present some preliminary imaging results of in vivo patient ultrasound data. Our preliminary clinical imaging results show promising of our breast ultrasound tomography system with two parallel transducer arrays for breast cancer imaging and characterization.

Compressed sensing for ultrasound computed tomography.

PubMed

van Sloun, Ruud; Pandharipande, Ashish; Mischi, Massimo; Demi, Libertario

2015-06-01

Ultrasound computed tomography (UCT) allows the reconstruction of quantitative tissue characteristics, such as speed of sound, mass density, and attenuation. Lowering its acquisition time would be beneficial; however, this is fundamentally limited by the physical time of flight and the number of transmission events. In this letter, we propose a compressed sensing solution for UCT. The adopted measurement scheme is based on compressed acquisitions, with concurrent randomised transmissions in a circular array configuration. Reconstruction of the image is then obtained by combining the born iterative method and total variation minimization, thereby exploiting variation sparsity in the image domain. Evaluation using simulated UCT scattering measurements shows that the proposed transmission scheme performs better than uniform undersampling, and is able to reduce acquisition time by almost one order of magnitude, while maintaining high spatial resolution.

A system for real-time measurement of the brachial artery diameter in B-mode ultrasound images.

PubMed

Gemignani, Vincenzo; Faita, Francesco; Ghiadoni, Lorenzo; Poggianti, Elisa; Demi, Marcello

2007-03-01

The measurement of the brachial artery diameter is frequently used in clinical studies for evaluating the flow-mediated dilation and, in conjunction with the blood pressure value, for assessing arterial stiffness. This paper presents a system for computing the brachial artery diameter in real-time by analyzing B-mode ultrasound images. The method is based on a robust edge detection algorithm which is used to automatically locate the two walls of the vessel. The measure of the diameter is obtained with subpixel precision and with a temporal resolution of 25 samples/s, so that the small dilations induced by the cardiac cycle can also be retrieved. The algorithm is implemented on a standalone video processing board which acquires the analog video signal from the ultrasound equipment. Results are shown in real-time on a graphical user interface. The system was tested both on synthetic ultrasound images and in clinical studies of flow-mediated dilation. Accuracy, robustness, and intra/inter observer variability of the method were evaluated.

Ultrasound Imaging of Muscle Contraction of the Tibialis Anterior in Patients with Facioscapulohumeral Dystrophy.

PubMed

Gijsbertse, Kaj; Goselink, Rianne; Lassche, Saskia; Nillesen, Maartje; Sprengers, André; Verdonschot, Nico; van Alfen, Nens; de Korte, Chris

2017-11-01

A need exists for biomarkers to diagnose, quantify and longitudinally follow facioscapulohumeral muscular dystrophy (FSHD) and many other neuromuscular disorders. Furthermore, the pathophysiological mechanisms leading to muscle weakness in most neuromuscular disorders are not completely understood. Dynamic ultrasound imaging (B-mode image sequences) in combination with speckle tracking is an easy, applicable and patient-friendly imaging tool to visualize and quantify muscle deformation. This dynamic information provides insight in the pathophysiological mechanisms and may help to distinguish the various stages of diseased muscle in FSHD. In this proof-of-principle study, we applied a speckle tracking technique to 2-D ultrasound image sequences to quantify the deformation of the tibialis anterior muscle in patients with FSHD and in healthy controls. The resulting deformation patterns were compared with muscle ultrasound echo intensity analysis (a measure of fat infiltration and dystrophy) and clinical outcome measures. Of the four FSHD patients, two patients had severe peroneal weakness and two patients had mild peroneal weakness on clinical examination. We found a markedly varied muscle deformation pattern between these groups: patients with severe peroneal weakness showed a different motion pattern of the tibialis anterior, with overall less displacement of the central tendon region, while healthy patients showed a non-uniform displacement pattern, with the central aponeurosis showing the largest displacement. Hence, dynamic muscle ultrasound of the tibialis anterior muscle in patients with FSHD revealed a distinctively different tissue deformation pattern among persons with and without tibialis anterior weakness. These findings could clarify the understanding of the pathophysiology of muscle weakness in FSHD patients. In addition, the change in muscle deformation shows good correlation with clinical measures and quantitative muscle ultrasound measurements. In

Development and Measurement of Preschoolers' Quantitative Knowledge

ERIC Educational Resources Information Center

Geary, David C.

2015-01-01

The collection of studies in this special issue make an important contribution to our understanding and measurement of the core cognitive and noncognitive factors that influence children's emerging quantitative competencies. The studies also illustrate how the field has matured, from a time when the quantitative competencies of infants and young…

The Use of B-Mode Ultrasound for Measuring Subcutaneous Fat Thickness on the Upper Arms.

ERIC Educational Resources Information Center

Weiss, Lawrence W.; Clark, Frank C.

1985-01-01

A study was carried out to investigate the potential use of B-mode ultrasound for measuring subcutaneous fat thickness at two arm sites. B-mode sonograms and skinfold measurements were found to be highly correlated for both men and women. (Author/MT)

What is ultrasound?

PubMed

Leighton, Timothy G

2007-01-01

This paper is based on material presented at the start of a Health Protection Agency meeting on ultrasound and infrasound. In answering the question 'what is ultrasound?', it shows that the simple description of a wave which transports mechanical energy through the local vibration of particles at frequencies of 20 kHz or more, with no net transport of the particles themselves, can in every respect be misleading or even incorrect. To explain the complexities responsible for this, the description of ultrasound is first built up from the fundamental properties of these local particle vibrations. This progresses through an exposition of the characteristics of linear waves, in order to explain the propensity for, and properties of, the nonlinear propagation which occurs in many practical ultrasonic fields. Given the Health Protection environment which framed the original presentation, explanation and examples are given of how these complexities affect issues of practical importance. These issues include the measurement and description of fields and exposures, and the ability of ultrasound to affect tissue (through microstreaming, streaming, cavitation, heating, etc.). It is noted that there are two very distinct regimes, in terms of wave characteristics and potential for bioeffect. The first concerns the use of ultrasound in liquids/solids, for measurement or material processing. For biomedical applications (where these two processes are termed diagnosis and therapy, respectively), the issue of hazard has been studied in depth, although this has not been done to such a degree for industrial uses of ultrasound in liquids/solids (sonar, non-destructive testing, ultrasonic processing etc.). However, in the second regime, that of the use of ultrasound in air, although the waves in question tend to be of much lower intensities than those used in liquids/solids, there is a greater mismatch between the extent to which hazard has been studied, and the growth in commercial

Connecting qualitative observation and quantitative measurement for enhancing quantitative literacy in plant anatomy course

NASA Astrophysics Data System (ADS)

Nuraeni, E.; Rahmat, A.

2018-05-01

Forming of cognitive schemes of plant anatomy concepts is performed by processing of qualitative and quantitative data obtained from microscopic observations. To enhancing student’s quantitative literacy, strategy of plant anatomy course was modified by adding the task to analyze quantitative data produced by quantitative measurement of plant anatomy guided by material course. Participant in this study was 24 biology students and 35 biology education students. Quantitative Literacy test, complex thinking in plant anatomy test and questioner used to evaluate the course. Quantitative literacy capability data was collected by quantitative literacy test with the rubric from the Association of American Colleges and Universities, Complex thinking in plant anatomy by test according to Marzano and questioner. Quantitative literacy data are categorized according to modified Rhodes and Finley categories. The results showed that quantitative literacy of biology education students is better than biology students.

Investigation into the quantitative and qualitative characteristics of choroidal melanoma through magnetic resonance imaging and B-scan ultrasound

PubMed Central

Papayiannis, Vassilis; Tsaousis, Konstantinos T; Kouskouras, Constantinos A; Haritanti, Afroditi; Diakonis, Vasilios F; Tsinopoulos, Ioannis T

2017-01-01

Objective To investigate the homogeneity and vascularity of choroidal melanoma through magnetic resonance imaging (MRI) and brightness modulation (B-mode) ultrasound scan and their correlation with dimensions of tumor, as well as to measure the sensitivity of both modalities in retinal detachment (RD) detection. Materials and methods This retrospective chart review included patients diagnosed with choroidal melanoma. All these patients underwent MRI scans using T2-weighted (T2-WI) and T1-weighted (T1-WI) sequences, before and after an intravenous injection of paramagnetic contrast material. The patients were also examined using a B-mode ultrasound scan, and the results from both modalities were compared (tumor homogeneity, tumor height, tumor base diameter, and tumor vascularity). Results Forty-two patients (mean age=65.33±12.51 years) with choroidal melanoma were included in the study. Homogeneity was confirmed in 16 patients through ultrasound scan, in 19 patients through T1-WI sequence, in 21 patients through T2-WI sequence, and in 25 patients through T1-WI sequence + contrast (gadolinium). Patients with homogenous tumors presented with lower (P=0.0045) mean height than that of those with nonhomogenous tumors, whereas no statistically significant difference was found for base diameter measurements (P=0.056). Patients with tumors of high vascularity presented with greater mean height (P=0.000638) and greater mean base diameter compared with those with tumors of low vascularity (P=0.019543). RD was detected in 26 patients through T1-WI sequence, in 13 patients through T2-WI sequence, in 26 patients through T1-WI sequence + contrast, and in 32 patients through ultrasound scan, which proved to be the most sensitive modality. Conclusion The height of choroidal melanoma was positively correlated with tumor’s homogeneity. Melanomas of greater height were found to be less homogenous, due to increased degeneration and higher occurrence of intratumoral hemorrhage. In

Nanobubble-Affibody: Novel ultrasound contrast agents for targeted molecular ultrasound imaging of tumor.

PubMed

Yang, Hengli; Cai, Wenbin; Xu, Lei; Lv, Xiuhua; Qiao, Youbei; Li, Pan; Wu, Hong; Yang, Yilin; Zhang, Li; Duan, Yunyou

2015-01-01

Nanobubbles (NBs), as novel ultrasound contrast agents (UCAs), have attracted increasing attention in the field of molecular ultrasound imaging for tumors. However, the preparation of uniform-sized NBs is considered to be controversial, and poor tumor selectivity in in vivo imaging has been reported. In this study, we fabricated uniform nano-sized NBs (478.2 ± 29.7 nm with polydispersity index of 0.164 ± 0.044, n = 3) using a thin-film hydration method by controlling the thickness of phospholipid films; we then conjugated the NBs with Affibody molecules to produce nano-sized UCAs referred to as NB-Affibody with specific affinity to human epidermal growth factor receptor type 2 (HER2)-overexpressing tumors. NB-Affibody presented good ultrasound enhancement, demonstrating a peak intensity of 104.5 ± 2.1 dB under ultrasound contrast scanning. Ex vivo experiments further confirmed that the NB-Affibody conjugates were capable of targeting HER2-expressing tumor cells in vivo with high affinity. The newly prepared nano-sized NB-Affibody conjugates were observed to be novel targeted UCAs for efficient and safe specific molecular imaging and may have potential applications in early cancer quantitative diagnosis and targeted therapy in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.

Musculoskeletal ultrasound and other imaging modalities in rheumatoid arthritis.

PubMed

Ohrndorf, Sarah; Werner, Stephanie G; Finzel, Stephanie; Backhaus, Marina

2013-05-01

This review refers to the use of musculoskeletal ultrasound in patients with rheumatoid arthritis (RA) both in clinical practice and research. Furthermore, other novel sensitive imaging modalities (high resolution peripheral quantitative computed tomography and fluorescence optical imaging) are introduced in this article. Recently published ultrasound studies presented power Doppler activity by ultrasound highly predictive for later radiographic erosions in patients with RA. Another study presented synovitis detected by ultrasound being predictive of subsequent structural radiographic destruction irrespective of the ultrasound modality (grayscale ultrasound/power Doppler ultrasound). Further studies are currently under way which prove ultrasound findings as imaging biomarkers in the destructive process of RA. Other introduced novel imaging modalities are in the validation process to prove their impact and significance in inflammatory joint diseases. The introduced imaging modalities show different sensitivities and specificities as well as strength and weakness belonging to the assessment of inflammation, differentiation of the involved structures and radiological progression. The review tries to give an answer regarding how to best integrate them into daily clinical practice with the aim to improve the diagnostic algorithms, the daily patient care and, furthermore, the disease's outcome.

Ultrasound is a reproducible and valid tool for measuring scar height in children with burn scars: A cross-sectional study of the psychometric properties and utility of the ultrasound and 3D camera.

PubMed

Simons, M; Kee, E Gee; Kimble, R; Tyack, Z

2017-08-01

The aim of this study was to investigate the reproducibility and validity of measuring scar height in children using ultrasound and 3D camera. Using a cross-sectional design, children with discrete burn scars were included. Reproducibility was tested using Intraclass Correlation Coefficient (ICC) for reliability, and percentage agreement within 1mm between test and re-test, standard error of measurement (SEM), smallest detectable change (SDC) and Bland Altman limits of agreement for agreement. Concurrent validity was tested using Spearman's rho for support of pre-specified hypotheses. Forty-nine participants (55 scars) were included. For ultrasound, test-retest and inter-rater reproducibility of scar thickness was acceptable for scarred skin (ICC=0.95, SDC=0.06cm and ICC=0.82, SDC=0.14cm). The ultrasound picked up changes of <1mm. Inter-rater reproducibility of maximal scar height using the 3D camera was acceptable (ICC=0.73, SDC=0.55cm). Construct validity of the ultrasound was supported with a strong correlation between the measure of scar thickness and observer ratings of thickness using the POSAS (ρ=0.61). Construct validity of the 3D camera was also supported with a moderate correlation (ρ=0.37) with the same measure using maximal scar height. The ultrasound is capable of detecting smaller changes or differences in scar thickness than the 3D camera, in children with burn scars. However agreement as part of reproducibility was lower than expected between raters for the ultrasound. Improving the accuracy of scar relocation may go some way to address agreement. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Electric Field Quantitative Measurement System and Method

NASA Technical Reports Server (NTRS)

Generazio, Edward R. (Inventor)

2016-01-01

A method and system are provided for making a quantitative measurement of an electric field. A plurality of antennas separated from one another by known distances are arrayed in a region that extends in at least one dimension. A voltage difference between at least one selected pair of antennas is measured. Each voltage difference is divided by the known distance associated with the selected pair of antennas corresponding thereto to generate a resulting quantity. The plurality of resulting quantities defined over the region quantitatively describe an electric field therein.

A Pilot Comparative Study of Quantitative Ultrasound, Conventional Ultrasound, and MRI for Predicting Histology-Determined Steatosis Grade in Adult Nonalcoholic Fatty Liver Disease

PubMed Central

Paige, Jeremy S.; Bernstein, Gregory S.; Heba, Elhamy; Costa, Eduardo A. C.; Fereirra, Marilia; Wolfson, Tanya; Gamst, Anthony C.; Valasek, Mark A.; Lin, Grace Y.; Han, Aiguo; Erdman, John W.; O’Brien, William D.; Andre, Michael P.; Loomba, Rohit; Sirlin, Claude B.

2017-01-01

OBJECTIVE The purpose of this study is to explore the diagnostic performance of two investigational quantitative ultrasound (QUS) parameters, attenuation coefficient and backscatter coefficient, in comparison with conventional ultrasound (CUS) and MRI-estimated proton density fat fraction (PDFF) for predicting histology-confirmed steatosis grade in adults with nonalcoholic fatty liver disease (NAFLD). SUBJECTS AND METHODS In this prospectively designed pilot study, 61 adults with histology-confirmed NAFLD were enrolled from September 2012 to February 2014. Subjects underwent QUS, CUS, and MRI examinations within 100 days of clinical-care liver biopsy. QUS parameters (attenuation coefficient and backscatter coefficient) were estimated using a reference phantom technique by two analysts independently. Three-point ordinal CUS scores intended to predict steatosis grade (1, 2, or 3) were generated independently by two radiologists on the basis of QUS features. PDFF was estimated using an advanced chemical shift–based MRI technique. Using histologic examination as the reference standard, ROC analysis was performed. Optimal attenuation coefficient, backscatter coefficient, and PDFF cutoff thresholds were identified, and the accuracy of attenuation coefficient, backscatter coefficient, PDFF, and CUS to predict steatosis grade was determined. Interobserver agreement for attenuation coefficient, backscatter coefficient, and CUS was analyzed. RESULTS CUS had 51.7% grading accuracy. The raw and cross-validated steatosis grading accuracies were 61.7% and 55.0%, respectively, for attenuation coefficient, 68.3% and 68.3% for backscatter coefficient, and 76.7% and 71.3% for MRI-estimated PDFF. Interobserver agreements were 53.3% for CUS (κ = 0.61), 90.0% for attenuation coefficient (κ = 0.87), and 71.7% for backscatter coefficient (κ = 0.82) (p < 0.0001 for all). CONCLUSION Preliminary observations suggest that QUS parameters may be more accurate and provide higher

A Pilot Comparative Study of Quantitative Ultrasound, Conventional Ultrasound, and MRI for Predicting Histology-Determined Steatosis Grade in Adult Nonalcoholic Fatty Liver Disease.

PubMed

Paige, Jeremy S; Bernstein, Gregory S; Heba, Elhamy; Costa, Eduardo A C; Fereirra, Marilia; Wolfson, Tanya; Gamst, Anthony C; Valasek, Mark A; Lin, Grace Y; Han, Aiguo; Erdman, John W; O'Brien, William D; Andre, Michael P; Loomba, Rohit; Sirlin, Claude B

2017-05-01

The purpose of this study is to explore the diagnostic performance of two investigational quantitative ultrasound (QUS) parameters, attenuation coefficient and backscatter coefficient, in comparison with conventional ultrasound (CUS) and MRI-estimated proton density fat fraction (PDFF) for predicting histology-confirmed steatosis grade in adults with nonalcoholic fatty liver disease (NAFLD). In this prospectively designed pilot study, 61 adults with histology-confirmed NAFLD were enrolled from September 2012 to February 2014. Subjects underwent QUS, CUS, and MRI examinations within 100 days of clinical-care liver biopsy. QUS parameters (attenuation coefficient and backscatter coefficient) were estimated using a reference phantom technique by two analysts independently. Three-point ordinal CUS scores intended to predict steatosis grade (1, 2, or 3) were generated independently by two radiologists on the basis of QUS features. PDFF was estimated using an advanced chemical shift-based MRI technique. Using histologic examination as the reference standard, ROC analysis was performed. Optimal attenuation coefficient, backscatter coefficient, and PDFF cutoff thresholds were identified, and the accuracy of attenuation coefficient, backscatter coefficient, PDFF, and CUS to predict steatosis grade was determined. Interobserver agreement for attenuation coefficient, backscatter coefficient, and CUS was analyzed. CUS had 51.7% grading accuracy. The raw and cross-validated steatosis grading accuracies were 61.7% and 55.0%, respectively, for attenuation coefficient, 68.3% and 68.3% for backscatter coefficient, and 76.7% and 71.3% for MRI-estimated PDFF. Interobserver agreements were 53.3% for CUS (κ = 0.61), 90.0% for attenuation coefficient (κ = 0.87), and 71.7% for backscatter coefficient (κ = 0.82) (p < 0.0001 for all). Preliminary observations suggest that QUS parameters may be more accurate and provide higher interobserver agreement than CUS for predicting hepatic

Quantitative assessment of placental perfusion by contrast-enhanced ultrasound in macaques and human subjects

PubMed Central

Roberts, Victoria HJ; Lo, Jamie O; Salati, Jennifer A; Lewandowski, Katherine S; Lindner, Jonathan R; Morgan, Terry K; Frias, Antonio E

2016-01-01

Background The utero-placental vascular supply is a critical determinant of placental function and fetal growth. Current methods for the in vivo assessment of placental blood flow are limited. Objective Here we demonstrate the feasibility of utilizing contrast-enhanced ultrasound to visualize and quantify perfusion kinetics in the intervillous space of the primate placenta. Study design Pregnant Japanese macaques were studied at mid second trimester and in the early third trimester. Markers of injury were assessed in placenta samples from animals with or without contrast-enhanced ultrasound exposure (n=6/group). Human subjects were recruited immediately prior to scheduled first trimester pregnancy termination. All studies were performed with maternal intravenous infusion of lipid-shelled octofluoropropane microbubbles with image acquisition using a multipulse contrast-specific algorithm with destruction-replenishment analysis of signal intensity for assessment of perfusion. Results In macaques, rate of perfusion in the intervillous space was increased with advancing gestation. No evidence of microvascular hemorrhage or acute inflammation was found in placental villous tissue and expression levels of caspase-3, nitrotyrosine and HSP70 as markers of apoptosis, nitrative and oxidative stress respectively were unchanged by contrast-enhanced ultrasound exposure. In humans, placental perfusion was visualized at 11wks gestation and preliminary data reveal regional differences in intervillous space perfusion within an individual placenta. By electron microscopy, we demonstrate no evidence of ultrastructure damage to the microvilli on the syncytiotrophoblast following first trimester ultrasound studies. Conclusions Use of contrast-enhanced ultrasound did not result in placental structural damage, and was able to identify intervillous space perfusion rate differences within a placenta. Contrast-enhanced ultrasound may offer a safe clinical tool for the identification of

High-frequency ultrasound evaluation of cellulite treated with the 1064 nm Nd:YAG laser.

PubMed

Bousquet-Rouaud, Regine; Bazan, Marie; Chaintreuil, Jean; Echague, Agustina Vila

2009-03-01

To investigate non-invasive laser treatment for cellulite using the 1064 nm Nd:YAG laser and to correlate clinical results with high-frequency skin ultrasound images. Twelve individuals of normal weight were treated on either the left or right posterior side of the thigh with the following parameters: fluence 30 J/cm, 18 mm spot size and dynamic cooling device pulse duration of 30 ms. Three treatments were performed at intervals of 3-4 weeks, and followed-up 1 and 3 months after the last session. Photographs and ultrasound imaging were assessed before each session. The 1064 nm Nd:YAG laser resulted in a tightening of the skin and an improvement in cellulite. No side effects were reported. High-resolution ultrasound imaging showed a significant improvement in dermis density and a reduction of dermis thickness. The method is described in detail in Appendix 1. Infra-red lasers may constitute a safe and effective treatment for cellulite and high-frequency ultrasound imaging provides a quantitative and objective measurement of the treatment efficacy.

Effect of mild pressure applied by the ultrasound transducer on fetal cephalic measurements at 20-24 weeks' gestation.

PubMed

Kliper, Yael; Ben-Ami, Moshe; Perlitz, Yuri

2014-01-01

The aim of this study was to assess the effect of mild pressure applied on the abdominal wall by the ultrasound transducer on fetal cephalic indices. We examined by ultrasound 60 fetuses of healthy women, at 20-24 weeks of pregnancy, during routine prenatal evaluation. For every fetus biparietal diameter and head circumference were measured, with and without applying mild pressure by the ultrasound transducer. The weight and gestational age (GA) were calculated. The pressure applied by the transducer had a significant effect on the cephalic indices and on the weight and GA evaluations (p < 0.001). Fetal positioning significantly affected the impact that applied pressure had on head circumference and on the weight evaluation derived from it (p < 0.05). Applied pressure by an abdominal ultrasound probe affects cephalic indices and the derived weight and GA estimations. This may lead to incorrect diagnoses or hide pathological findings. The effect of applied pressure depends on fetal positioning. The examiner must be aware of this effect when evaluating the results of the measurements.

Non-contact and through-clothing measurement of the heart rate using ultrasound vibrocardiography.

PubMed

Jeger-Madiot, Nathan; Gateau, Jérôme; Fink, Mathias; Ing, Ros-Kiri

2017-12-01

We present a novel non-contact system for monitoring the heart rate on human subjects with clothes. Our approach is based on vibrocardiography, and measures locally skin displacements. Vibrocardiography with a laser Doppler vibrometer already allows monitoring of this vital sign, but can only be used on bare skin and requires an expensive piece of equipment. We propose here to use an airborne pulse-Doppler ultrasound system operating in the 20-60 kHz range, and comprised of an emitter focusing the ultrasound pulses on skin and a microphone recording the reflected waves. Our implementation was validated in vitro and on two healthy human subjects, using simultaneously laser vibrocardiography and electrocardiography as references. Accurate measurements of the heart rate on clothed skin suggest that our non-contact ultrasonic method could be implemented both inside and outside the clinical environment, and therefore benefit both medical and safety applications. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Prediction of hip fracture risk by quantitative ultrasound in more than 7000 Swiss women > or =70 years of age: comparison of three technologically different bone ultrasound devices in the SEMOF study.

PubMed

Krieg, Marc-Antoine; Cornuz, Jacques; Ruffieux, Christiane; Van Melle, Guy; Büche, Daniel; Dambacher, Maximilian A; Hans, Didier; Hartl, Florian; Häuselmann, Hansjorg J; Kraenzlin, Marius; Lippuner, Kurt; Neff, Maurus; Pancaldi, Pierro; Rizzoli, Rene; Tanzi, Franco; Theiler, Robert; Tyndall, Alan; Wimpfheimer, Claus; Burckhardt, Peter

2006-09-01

To compare the prediction of hip fracture risk of several bone ultrasounds (QUS), 7062 Swiss women > or =70 years of age were measured with three QUSs (two of the heel, one of the phalanges). Heel QUSs were both predictive of hip fracture risk, whereas the phalanges QUS was not. As the number of hip fracture is expected to increase during these next decades, it is important to develop strategies to detect subjects at risk. Quantitative bone ultrasound (QUS), an ionizing radiation-free method, which is transportable, could be interesting for this purpose. The Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture Risk (SEMOF) study is a multicenter cohort study, which compared three QUSs for the assessment of hip fracture risk in a sample of 7609 elderly ambulatory women > or =70 years of age. Two QUSs measured the heel (Achilles+; GE-Lunar and Sahara; Hologic), and one measured the heel (DBM Sonic 1200; IGEA). The Cox proportional hazards regression was used to estimate the hazard of the first hip fracture, adjusted for age, BMI, and center, and the area under the ROC curves were calculated to compare the devices and their parameters. From the 7609 women who were included in the study, 7062 women 75.2 +/- 3.1 (SD) years of age were prospectively followed for 2.9 +/- 0.8 years. Eighty women reported a hip fracture. A decrease by 1 SD of the QUS variables corresponded to an increase of the hip fracture risk from 2.3 (95% CI, 1.7, 3.1) to 2.6 (95% CI, 1.9, 3.4) for the three variables of Achilles+ and from 2.2 (95% CI, 1.7, 3.0) to 2.4 (95% CI, 1.8, 3.2) for the three variables of Sahara. Risk gradients did not differ significantly among the variables of the two heel QUS devices. On the other hand, the phalanges QUS (DBM Sonic 1200) was not predictive of hip fracture risk, with an adjusted hazard risk of 1.2 (95% CI, 0.9, 1.5), even after reanalysis of the digitalized data and using different cut-off levels (1700 or 1570 m/s). In this elderly women

Use of quantitative ultrasound of the hand phalanges in the diagnosis of two different osteoporotic syndromes: Cushing's syndrome and postmenopausal osteoporosis.

PubMed

Camozzi, V; Carraro, V; Zangari, M; Fallo, F; Mantero, F; Luisetto, G

2004-06-01

The aim of this study was to assess the ability of the quantitative ultrasound of the hand phalanges to detect different types of osteoporosis resulting from different pathogenetic mechanisms. For this purpose, postmenopausal and glucocorticoid-induced osteoporosis was studied. Thirteen female patients with Cushing's syndrome (CS) resulting from pituitary-dependent bilateral adrenal hyperplasia (10 patients) and from adrenal adenoma (3 patients), and 32 postmenopausal osteoporotic (OP) women, were examined. The two groups of patients were comparable for body mass index (BMI), but CS patients were significantly younger than OP ones (CS 44.5+/-11.6; OP: 73.9+/-3.6). All the patients had femoral neck bone mineral density (BMD) T-score less than -2.0. Cushing patients had a femoral neck BMD similar to that of OP patients (CS: 603+/-66 mg/cm2; OP: 628+/-69 mg/cm2; p=0.19). In contrast, amplitude-dependent speed of sound (AD-SoS) was significantly higher in CS patients than in OP patients (CS: 1997+/-91 m/s; OP: 1707+/-114 m/s; p<0.0001). By adjusting DXA and ultrasound parameters according to age, femoral neck BMD was significantly lower in CS patients and AD-SoS remained significantly higher than in OP patients. These findings indicate that these two different kinds of osteoporosis can be distinguished by ultrasonography and that ultrasound parameters alone cannot be used for evaluating skeletal status in CS patients.

Can activity within the external abdominal oblique be measured using real-time ultrasound imaging?

PubMed

John, E K; Beith, I D

2007-11-01

Differences in the function of the anterolateral abdominal muscles have been the subject of much investigation, but primarily using electromyography. Recently changes in thickness of transversus abdominis and internal oblique measured from real-time ultrasound images have been shown to represent activity within these muscles. However it is still unclear if such a change in thickness in external oblique similarly represents activity within that muscle. The purpose of this study was to investigate the relationship between change in thickness and muscle activity in the external oblique using real-time ultrasound and surface electromyography. Simultaneous measurements of electromyography and real-time ultrasound images of external oblique were studied in up to 24 subjects during two tasks compared to the muscle at rest (1) isometric trunk rotation and (2) drawing in the lower abdomen. Changes in muscle thickness correlated significantly with electromyography during isometric trunk rotation in the majority of subjects but with a significant difference between subjects. In contrast, the relationship between change in thickness and electrical activity in the muscle when drawing in the lower abdomen was significant in less than 50% of subjects and the muscle often got thinner. Thickness changes of external oblique can be used as a valid indicator of electromyography activity during isometric trunk rotation, though the relationship is not as good as previously published data for transversus abdominis. Thickness changes of external oblique measured during lower abdominal drawing in cannot be used to detect activity within this muscle.

Recent technological advancements in cardiac ultrasound imaging.

PubMed

Dave, Jaydev K; Mc Donald, Maureen E; Mehrotra, Praveen; Kohut, Andrew R; Eisenbrey, John R; Forsberg, Flemming

2018-03-01

About 92.1 million Americans suffer from at least one type of cardiovascular disease. Worldwide, cardiovascular diseases are the number one cause of death (about 31% of all global deaths). Recent technological advancements in cardiac ultrasound imaging are expected to aid in the clinical diagnosis of many cardiovascular diseases. This article provides an overview of such recent technological advancements, specifically focusing on tissue Doppler imaging, strain imaging, contrast echocardiography, 3D echocardiography, point-of-care echocardiography, 3D volumetric flow assessments, and elastography. With these advancements ultrasound imaging is rapidly changing the domain of cardiac imaging. The advantages offered by ultrasound imaging include real-time imaging, imaging at patient bed-side, cost-effectiveness and ionizing-radiation-free imaging. Along with these advantages, the steps taken towards standardization of ultrasound based quantitative markers, reviewed here, will play a major role in addressing the healthcare burden associated with cardiovascular diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrasound measurements of live and carcass traits in Tswana goat kids raised under semi-intensive system in South-eastern Botswana.

PubMed

Monau, Phetogo Ineeleng; Nsoso, Shalaulani James; Waugh, Esau Emmanuel; Sharma, Surender Pal

2013-03-01

The aim of this study was to characterise ultrasound measurements of live and carcass traits in intact males, females and castrated Tswana goat kids from birth to 12 months of age raised under semi-intensive system in South-eastern Botswana. Measurements were recorded in 15 castrates, 15 intact males and 15 female Tswana goat kids randomly selected at birth. Ultrasonic fat and muscle depths were measured at the first, third/fourth, sixth/seventh, ninth/tenth and 12th/13th thoracic; first, third and fifth lumbar and first, second/third and fourth/fifth sternal vertebrae, fortnightly for the first 6 months and then monthly for the remaining 6 months. The animals were stunned and humanely slaughtered at 12 months of age, and ultrasound and shatterproof ruler were used to measure fat and muscle depths on the carcasses at similar sites as on live animals. A real-time B-mode ultrasound scanner fitted with LV2-1 probe operating at 7.5 MHz (Explorer V5 Vet Laptop B-Ultrasonic Scanner UMC Technology Development Co., Ltd, China) was used to predict ultrasound measurements on live animals and their carcasses. Data were analysed using general linear model in statistical analysis system. Muscle depth measurements increased significantly (p < 0.05) with age in all sites of measurements. However, there was no significant difference between the sexes at different sites of muscle depth measurements at the same age. Muscle depth at the sternal vertebrae was significantly deeper (almost 55 mm at 12 months of age) than 16 mm at thoracic and 16 mm at lumbar vertebrae at 12 and 8 months of age, respectively. No subcutaneous fat depth measurements were recorded in the lumbar vertebrae (0.00 ± 0.00) and the thoracic (0.00 ± 0.00) regions in all sex groups. However, fourth and fifth sternal vertebrae showed considerably deeper amount of subcutaneous fat suitable for taking fat measurements as age increases (2.07 ± 0.23 mm females, 1.50 ± 0.43 mm intact

Ultrasound field measurement using a binary lens

PubMed Central

Clement, G.T.; Nomura, H.; Kamakura, T.

2014-01-01

Field characterization methods using a scattering target in the absence of a point-like receiver have been well described in which scattering is recorded by a relatively large receiver located outside the field of measurement. Unfortunately, such methods are prone to artifacts due to averaging across the receiver surface. To avoid this problem while simultaneously increasing the gain of a received signal, the present study introduces a binary plate lens designed to focus spherically-spreading waves onto a planar region having a nearly-uniform phase proportional to that of the target location. The lens is similar to a zone plate, but modified to produce a biconvex-like behavior, such that it focuses both planar and spherically spreading waves. A measurement device suitable for characterizing narrowband ultrasound signals in air is designed around this lens by coupling it to a target and planar receiver. A prototype device is constructed and used to characterize the field of a highly-focused 400 kHz air transducer along 2 radial lines. Comparison of the measurements with numeric predictions formed from nonlinear acoustic simulation showed good relative pressure correlation, with mean differences of 10% and 12% over center 3dB FWHM drop and 12% and 17% over 6dB. PMID:25643084

Genome-wide association study meta-analysis for quantitative ultrasound parameters of bone identifies five novel loci for broadband ultrasound attenuation.

PubMed

Mullin, Benjamin H; Zhao, Jing Hua; Brown, Suzanne J; Perry, John R B; Luan, Jian'an; Zheng, Hou-Feng; Langenberg, Claudia; Dudbridge, Frank; Scott, Robert; Wareham, Nick J; Spector, Tim D; Richards, J Brent; Walsh, John P; Wilson, Scott G

2017-07-15

Osteoporosis is a common and debilitating bone disease that is characterised by low bone mineral density, typically assessed using dual-energy X-ray absorptiometry. Quantitative ultrasound (QUS), commonly utilising the two parameters velocity of sound (VOS) and broadband ultrasound attenuation (BUA), is an alternative technology used to assess bone properties at peripheral skeletal sites. The genetic influence on the bone qualities assessed by QUS remains an under-studied area. We performed a comprehensive genome-wide association study (GWAS) including low-frequency variants (minor allele frequency ≥0.005) for BUA and VOS using a discovery population of individuals with whole-genome sequence (WGS) data from the UK10K project (n = 1268). These results were then meta-analysed with those from two deeply imputed GWAS replication cohorts (n = 1610 and 13 749). In the gender-combined analysis, we identified eight loci associated with BUA and five with VOS at the genome-wide significance level, including three novel loci for BUA at 8p23.1 (PPP1R3B), 11q23.1 (LOC387810) and 22q11.21 (SEPT5) (P = 2.4 × 10-8 to 1.6 × 10-9). Gene-based association testing in the gender-combined dataset revealed eight loci associated with BUA and seven with VOS after correction for multiple testing, with one novel locus for BUA at FAM167A (8p23.1) (P = 1.4 × 10-6). An additional novel locus for BUA was seen in the male-specific analysis at DEFB103B (8p23.1) (P = 1.8 × 10-6). Fracture analysis revealed significant associations between variation at the WNT16 and RSPO3 loci and fracture risk (P = 0.004 and 4.0 × 10-4, respectively). In conclusion, by performing a large GWAS meta-analysis for QUS parameters of bone using a combination of WGS and deeply imputed genotype data, we have identified five novel genetic loci associated with BUA. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email

Reproducibility and interoperator reliability of obtaining images and measurements of the cervix and uterus with brachytherapy treatment applicators in situ using transabdominal ultrasound.

PubMed

van Dyk, Sylvia; Garth, Margaret; Oates, Amanda; Kondalsamy-Chennakesavan, Srinivas; Schneider, Michal; Bernshaw, David; Narayan, Kailash

2016-01-01

To validate interoperator reliability of brachytherapy radiation therapists (RTs) in obtaining an ultrasound image and measuring the cervix and uterine dimensions using transabdominal ultrasound. Patients who underwent MRI with applicators in situ after the first insertion were included in the study. Imaging was performed by three RTs (RT1, RT2, and RT3) with varying degrees of ultrasound experience. All RTs were required to obtain a longitudinal planning image depicting the applicator in the uterine canal and measure the cervix and uterus. The MRI scan, taken 1 hour after the ultrasound, was used as the reference standard against which all measurements were compared. Measurements were analyzed with intraclass correlation coefficient and Bland-Altman plots. All RTs were able to obtain a suitable longitudinal image for each patient in the study. Mean differences (SD) between MRI and ultrasound measurements obtained by RTs ranged from 3.5 (3.6) to 4.4 (4.23) mm and 0 (3.0) to 0.9 (2.5) mm on the anterior and posterior surface of the cervix, respectively. Intraclass correlation coefficient for absolute agreement between MRI and RTs was >0.9 for all posterior measurement points in the cervix and ranged from 0.41 to 0.92 on the anterior surface. Measurements were not statistically different between RTs at any measurement point. RTs with variable training attained high levels of interoperator reliability when using transabdominal ultrasound to obtain images and measurements of the uterus and cervix with brachytherapy applicators in situ. Access to training and use of a well-defined protocol assist in achieving these high levels of reliability. Copyright © 2016 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Investigation of Post-mortem Tissue Effects Using Long-time Decorrelation Ultrasound

NASA Astrophysics Data System (ADS)

Csány, Gergely; Balogh, Lajos; Gyöngy, Miklós

Decorrelation ultrasound is being increasingly used to investigate long-term biological phenomena. In the current work, ultrasound image sequences of mice who did not survive anesthesia (in a separate investigation) were analyzed and post-mortem tissue effects were observed via decorrelation calculation. A method was developed to obtain a quantitative parameter characterizing the rate of decorrelation. The results show that ultrasound decorrelation imaging is an effective method of observing post-mortem tissue effects and point to further studies elucidating the mechanism behind these effects.

Measured acoustic intensities for clinical diagnostic ultrasound transducers and correlation with thermal index.

PubMed

Retz, K; Kotopoulis, S; Kiserud, T; Matre, K; Eide, G E; Sande, R

2017-08-01

To investigate if the thermal index for bone (TIB) displayed on screen is an adequate predictor for the derated spatial-peak temporal-average (I SPTA .3 ) and spatial-peak pulse-average (I SPPA .3 ) acoustic intensities in a selection of clinical diagnostic ultrasound machines and transducers. We calibrated five clinical diagnostic ultrasound scanners and 10 transducers, using two-dimensional grayscale, color Doppler and pulsed-wave Doppler, both close to and far from the transducer, with a TIB between 0.1 and 4.0, recording 103 unique measurements. Acoustic measurements were performed in a bespoke three-axis computer-controlled scanning tank, using a 200-μm-diameter calibrated needle hydrophone. There was significant but poor correlation between the acoustic intensities and the on-screen TIB. At a TIB of 0.1, the I SPTA .3 range was 0.51-50.49 mW/cm 2 and the I SPPA .3 range was 0.01-207.29 W/cm 2 . At a TIB of 1.1, the I SPTA .3 range was 19.02-309.44 mW/cm 2 and the I SPPA .3 range was 3.87-51.89 W/cm 2 . TIB is a poor predictor for I SPTA .3 and I SPPA .3 and for the potential bioeffects of clinical diagnostic ultrasound scanners. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Exploratory Analysis of Carbon Dioxide Levels and Ultrasound Measures of the Eye During ISS Missions

NASA Technical Reports Server (NTRS)

Schaefer, C.; Young, M.; Mason, S.; Coble, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Law. J.; Alexander, D.; Ryder, V. Myers;

Evaluations of UltraiQ software for objective ultrasound image quality assessment using images from a commercial scanner.

PubMed

Long, Zaiyang; Tradup, Donald J; Stekel, Scott F; Gorny, Krzysztof R; Hangiandreou, Nicholas J

2018-03-01

We evaluated a commercially available software package that uses B-mode images to semi-automatically measure quantitative metrics of ultrasound image quality, such as contrast response, depth of penetration (DOP), and spatial resolution (lateral, axial, and elevational). Since measurement of elevational resolution is not a part of the software package, we achieved it by acquiring phantom images with transducers tilted at 45 degrees relative to the phantom. Each measurement was assessed in terms of measurement stability, sensitivity, repeatability, and semi-automated measurement success rate. All assessments were performed on a GE Logiq E9 ultrasound system with linear (9L or 11L), curved (C1-5), and sector (S1-5) transducers, using a CIRS model 040GSE phantom. In stability tests, the measurements of contrast, DOP, and spatial resolution remained within a ±10% variation threshold in 90%, 100%, and 69% of cases, respectively. In sensitivity tests, contrast, DOP, and spatial resolution measurements followed the expected behavior in 100%, 100%, and 72% of cases, respectively. In repeatability testing, intra- and inter-individual coefficients of variations were equal to or less than 3.2%, 1.3%, and 4.4% for contrast, DOP, and spatial resolution (lateral and axial), respectively. The coefficients of variation corresponding to the elevational resolution test were all within 9.5%. Overall, in our assessment, the evaluated package performed well for objective and quantitative assessment of the above-mentioned image qualities under well-controlled acquisition conditions. We are finding it to be useful for various clinical ultrasound applications including performance comparison between scanners from different vendors. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Mapping cardiac fiber orientations from high-resolution DTI to high-frequency 3D ultrasound

NASA Astrophysics Data System (ADS)

Qin, Xulei; Wang, Silun; Shen, Ming; Zhang, Xiaodong; Wagner, Mary B.; Fei, Baowei

2014-03-01

The orientation of cardiac fibers affects the anatomical, mechanical, and electrophysiological properties of the heart. Although echocardiography is the most common imaging modality in clinical cardiac examination, it can only provide the cardiac geometry or motion information without cardiac fiber orientations. If the patient's cardiac fiber orientations can be mapped to his/her echocardiography images in clinical examinations, it may provide quantitative measures for diagnosis, personalized modeling, and image-guided cardiac therapies. Therefore, this project addresses the feasibility of mapping personalized cardiac fiber orientations to three-dimensional (3D) ultrasound image volumes. First, the geometry of the heart extracted from the MRI is translated to 3D ultrasound by rigid and deformable registration. Deformation fields between both geometries from MRI and ultrasound are obtained after registration. Three different deformable registration methods were utilized for the MRI-ultrasound registration. Finally, the cardiac fiber orientations imaged by DTI are mapped to ultrasound volumes based on the extracted deformation fields. Moreover, this study also demonstrated the ability to simulate electricity activations during the cardiac resynchronization therapy (CRT) process. The proposed method has been validated in two rat hearts and three canine hearts. After MRI/ultrasound image registration, the Dice similarity scores were more than 90% and the corresponding target errors were less than 0.25 mm. This proposed approach can provide cardiac fiber orientations to ultrasound images and can have a variety of potential applications in cardiac imaging.

Finite element simulation of crack depth measurements in concrete using diffuse ultrasound

NASA Astrophysics Data System (ADS)

Seher, Matthias; Kim, Jin-Yeon; Jacobs, Laurence J.

2012-05-01

This research simulates the measurements of crack depth in concrete using diffuse ultrasound. The finite element method is employed to simulate the ultrasonic diffusion process around cracks with different geometrical shapes, with the goal of gaining physical insight into the data obtained from experimental measurements. The commercial finite element software Ansys is used to implement the two-dimensional concrete model. The model is validated with an analytical solution and experimental results. It is found from the simulation results that preliminary knowledge of the crack geometry is required to interpret the energy evolution curves from measurements and to correctly determine the crack depth.

Quantitative measures for redox signaling.

PubMed

Pillay, Ché S; Eagling, Beatrice D; Driscoll, Scott R E; Rohwer, Johann M

2016-07-01

Redox signaling is now recognized as an important regulatory mechanism for a number of cellular processes including the antioxidant response, phosphokinase signal transduction and redox metabolism. While there has been considerable progress in identifying the cellular machinery involved in redox signaling, quantitative measures of redox signals have been lacking, limiting efforts aimed at understanding and comparing redox signaling under normoxic and pathogenic conditions. Here we have outlined some of the accepted principles for redox signaling, including the description of hydrogen peroxide as a signaling molecule and the role of kinetics in conferring specificity to these signaling events. Based on these principles, we then develop a working definition for redox signaling and review a number of quantitative methods that have been employed to describe signaling in other systems. Using computational modeling and published data, we show how time- and concentration- dependent analyses, in particular, could be used to quantitatively describe redox signaling and therefore provide important insights into the functional organization of redox networks. Finally, we consider some of the key challenges with implementing these methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Microbubble and ultrasound radioenhancement of bladder cancer

PubMed Central

Tran, W T; Iradji, S; Sofroni, E; Giles, A; Eddy, D; Czarnota, G J

2012-01-01

Background: Tumour vasculature is an important component of tumour growth and survival. Recent evidence indicates tumour vasculature also has an important role in tumour radiation response. In this study, we investigated ultrasound and microbubbles to enhance the effects of radiation. Methods: Human bladder cancer HT-1376 xenografts in severe combined immuno-deficient mice were used. Treatments consisted of no, low and high concentrations of microbubbles and radiation doses of 0, 2 and 8 Gy in short-term and longitudinal studies. Acute response was assessed 24 h after treatment and longitudinal studies monitored tumour response weekly up to 28 days using power Doppler ultrasound imaging for a total of 9 conditions (n=90 animals). Results: Quantitative analysis of ultrasound data revealed reduced blood flow with ultrasound-microbubble treatments alone and further when combined with radiation. Tumours treated with microbubbles and radiation revealed enhanced cell death, vascular normalisation and areas of fibrosis. Longitudinal data demonstrated a reduced normalised vascular index and increased tumour cell death in both low and high microbubble concentrations with radiation. Conclusion: Our study demonstrated that ultrasound-mediated microbubble exposure can enhance radiation effects in tumours, and can lead to enhanced tumour cell death. PMID:22790798

Measurement of the ultrasound attenuation and dispersion in whole human blood and its components from 0-70 MHz.

PubMed

Treeby, Bradley E; Zhang, Edward Z; Thomas, Alison S; Cox, Ben T

2011-02-01

The ultrasound attenuation coefficient and dispersion from 0-70 MHz in whole human blood and its components (red blood cells and plasma) at 37°C is reported. The measurements are made using a fixed path substitution technique that exploits optical mechanisms for the generation and detection of ultrasound. This allows the measurements to cover a broad frequency range with a single source and receiver. The measured attenuation coefficient and dispersion in solutions of red blood cells and physiological saline for total haemoglobin concentrations of 10, 15 and 20 g/dL are presented. The attenuation coefficient and dispersion in whole human blood taken from four healthy volunteers by venipuncture is also reported. The power law dependence of the attenuation coefficient is shown to vary across the measured frequency range. This is due to the varying frequency dependence of the different mechanisms responsible for the attenuation. The attenuation coefficient measured at high frequencies is found to be significantly higher than that predicted by historical power law parameters. A review of the attenuation mechanisms in blood along with previously reported experimental measurements is given. Values for the sound speed and density in the tested samples are also presented. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Extracting cardiac myofiber orientations from high frequency ultrasound images

NASA Astrophysics Data System (ADS)

Qin, Xulei; Cong, Zhibin; Jiang, Rong; Shen, Ming; Wagner, Mary B.; Kirshbom, Paul; Fei, Baowei

2013-03-01

Cardiac myofiber plays an important role in stress mechanism during heart beating periods. The orientation of myofibers decides the effects of the stress distribution and the whole heart deformation. It is important to image and quantitatively extract these orientations for understanding the cardiac physiological and pathological mechanism and for diagnosis of chronic diseases. Ultrasound has been wildly used in cardiac diagnosis because of its ability of performing dynamic and noninvasive imaging and because of its low cost. An extraction method is proposed to automatically detect the cardiac myofiber orientations from high frequency ultrasound images. First, heart walls containing myofibers are imaged by B-mode high frequency (<20 MHz) ultrasound imaging. Second, myofiber orientations are extracted from ultrasound images using the proposed method that combines a nonlinear anisotropic diffusion filter, Canny edge detector, Hough transform, and K-means clustering. This method is validated by the results of ultrasound data from phantoms and pig hearts.

Accurate acoustic power measurement for low-intensity focused ultrasound using focal axial vibration velocity

NASA Astrophysics Data System (ADS)

Tao, Chenyang; Guo, Gepu; Ma, Qingyu; Tu, Juan; Zhang, Dong; Hu, Jimin

2017-07-01

Low-intensity focused ultrasound is a form of therapy that can have reversible acoustothermal effects on biological tissue, depending on the exposure parameters. The acoustic power (AP) should be chosen with caution for the sake of safety. To recover the energy of counteracted radial vibrations at the focal point, an accurate AP measurement method using the focal axial vibration velocity (FAVV) is proposed in explicit formulae and is demonstrated experimentally using a laser vibrometer. The experimental APs for two transducers agree well with theoretical calculations and numerical simulations, showing that AP is proportional to the square of the FAVV, with a fixed power gain determined by the physical parameters of the transducers. The favorable results suggest that the FAVV can be used as a valuable parameter for non-contact AP measurement, providing a new strategy for accurate power control for low-intensity focused ultrasound in biomedical engineering.

Improved accuracy of ultrasound-guided therapies using electromagnetic tracking: in-vivo speed of sound measurements

NASA Astrophysics Data System (ADS)

Samboju, Vishal; Adams, Matthew; Salgaonkar, Vasant; Diederich, Chris J.; Cunha, J. Adam M.

2017-02-01

The speed of sound (SOS) for ultrasound devices used for imaging soft tissue is often calibrated to water, 1540 m/s1 , despite in-vivo soft tissue SOS varying from 1450 to 1613 m/s2 . Images acquired with 1540 m/s and used in conjunction with stereotactic external coordinate systems can thus result in displacement errors of several millimeters. Ultrasound imaging systems are routinely used to guide interventional thermal ablation and cryoablation devices, or radiation sources for brachytherapy3 . Brachytherapy uses small radioactive pellets, inserted interstitially with needles under ultrasound guidance, to eradicate cancerous tissue4 . Since the radiation dose diminishes with distance from the pellet as 1/r2 , imaging uncertainty of a few millimeters can result in significant erroneous dose delivery5,6. Likewise, modeling of power deposition and thermal dose accumulations from ablative sources are also prone to errors due to placement offsets from SOS errors7 . This work presents a method of mitigating needle placement error due to SOS variances without the need of ionizing radiation2,8. We demonstrate the effects of changes in dosimetry in a prostate brachytherapy environment due to patientspecific SOS variances and the ability to mitigate dose delivery uncertainty. Electromagnetic (EM) sensors embedded in the brachytherapy ultrasound system provide information regarding 3D position and orientation of the ultrasound array. Algorithms using data from these two modalities are used to correct bmode images to account for SOS errors. While ultrasound localization resulted in >3 mm displacements, EM resolution was verified to <1 mm precision using custom-built phantoms with various SOS, showing 1% accuracy in SOS measurement.

High pulse repetition frequency ultrasound system for ex vivo measurement of mechanical properties of crystalline lenses with laser-induced microbubble interrogated by acoustic radiation force

PubMed Central

Yoon, Sangpil; Aglyamov, Salavat; Karpiouk, Andrei; Emelianov, Stanislav

2012-01-01

A high pulse repetition frequency ultrasound system for ex vivo measurement of mechanical properties of animal crystalline lens was developed and validated. We measured the bulk displacement of laser-induced microbubbles created at different positions within the lens using nanosecond laser pulses. An impulsive acoustic radiation force was applied to the microbubble, and spatio-temporal measurements of the microbubble displacement were assessed using a custom-made high pulse repetition frequency ultrasound system consisting of two 25 MHz focused ultrasound transducers. One of these transducers was used to emit a train of ultrasound pulses and another transducer was used to receive the ultrasound echoes reflected from the microbubble. The developed system was operating at 1 MHz pulse repetition frequency. Based on measured motion of the microbubble, the Young’s moduli of surrounding tissue were reconstructed and the values were compared with those measured using indentation test. Measured values of Young’s moduli of 4 bovine lenses ranged from 2.6±0.1 to 26±1.4 kPa and there was good agreement between the two methods. Therefore, our studies, utilizing the high pulse repetition frequency ultrasound system, suggest that the developed approach can be used to assess the mechanical properties of ex vivo crystalline lenses. Furthermore, the potential of the presented approach for in vivo measurements is discussed. PMID:22797709

Bone mineral density changes during pregnancy in actively exercising women as measured by quantitative ultrasound.

PubMed

To, William W K; Wong, Margaret W N

2012-08-01

To evaluate whether bone mineral density (BMD) changes in women engaged in active exercises during pregnancy would be different from non-exercising women. Consecutive patients with singleton pregnancies who were engaged in active exercise training during pregnancy were prospectively recruited over a period of 6 months. Quantitative USG measurements of the os calcis BMD were performed at 14-20 weeks and at 36-38 weeks. These patients were compared to a control cohort of non-exercising low-risk women. A total of 24 physically active women undergoing active physical training of over 10 h per week at 20 weeks gestation and beyond (mean 13.1 h, SD 3.3) were compared to 94 non-exercising low-risk women. A marginal fall in BMD of 0.015 g/cm(2) (SD 0.034) was demonstrable from early to late gestation in the exercising women, which was significantly lower than that of non-exercising women (0.041 g/cm(2); SD 0.042; p = 0.005). Logistic regression models confirmed that active exercises in pregnancy were significantly associated with the absence of or less BMD loss in pregnancy. In women actively engaged in physical training during pregnancy, the physiological fall in BMD during pregnancy was apparently less compared to those who did not regularly exercise.

Comparison of grey scale median (GSM) measurement in ultrasound images of human carotid plaques using two different softwares.

PubMed

Östling, Gerd; Persson, Margaretha; Hedblad, Bo; Gonçalves, Isabel

2013-11-01

Grey scale median (GSM) measured on ultrasound images of carotid plaques has been used for several years now in research to find the vulnerable plaque. Centres have used different software and also different methods for GSM measurement. This has resulted in a wide range of GSM values and cut-off values for the detection of the vulnerable plaque. The aim of this study was to compare the values obtained with two different softwares, using different standardization methods, for the measurement of GSM on ultrasound images of carotid human plaques. GSM was measured with Adobe Photoshop(®) and with Artery Measurement System (AMS) on duplex ultrasound images of 100 consecutive medium- to large-sized carotid plaques of the Beta-blocker Cholesterol-lowering Asymptomatic Plaque Study (BCAPS). The mean values of GSM were 35·2 ± 19·3 and 55·8 ± 22·5 for Adobe Photoshop(®) and AMS, respectively. Mean difference was 20·45 (95% CI: 19·17-21·73). Although the absolute values of GSM differed, the agreement between the two measurements was good, correlation coefficient 0·95. A chi-square test revealed a kappa value of 0·68 when studying quartiles of GSM. The intra-observer variability was 1·9% for AMS and 2·5% for Adobe Photoshop. The difference between softwares and standardization methods must be taken into consideration when comparing studies. To avoid these problems, researcher should come to a consensus regarding software and standardization method for GSM measurement on ultrasound images of plaque in the arteries. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Monitoring Progression of Amyotrophic Lateral Sclerosis Using Ultrasound Morpho-Textural Muscle Biomarkers: A Pilot Study.

PubMed

Martínez-Payá, Jacinto J; Ríos-Díaz, José; Medina-Mirapeix, Francesc; Vázquez-Costa, Juan F; Del Baño-Aledo, María Elena

2018-01-01

The need is increasing for progression biomarkers that allow the loss of motor neurons in amyotrophic lateral sclerosis (ALS) to be monitored in clinical trials. In this prospective longitudinal study, muscle thickness, echointensity, echovariation and gray level co-occurrence matrix textural features are examined as possible progression ultrasound biomarkers in ALS patients during a 5-mo follow-up period. We subjected 13 patients to 3 measurements for 20 wk. They showed a significant loss of muscle, an evident tendency to loss of thickness and increased echointensity and echovariation. In regard to textural parameters, muscle heterogeneity tended to increase as a result of the neoformation of non-contractile tissue through denervation. Considering some limitations of the study, the quantitative muscle ultrasound biomarkers evaluated showed a promising ability to monitor patients affected by ALS. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

[Menopause and ultrasonographic measurements of calcaneus].

PubMed

López-Caudana, Alma Ethelia; Castillo-Calderón, María Griselda; Ávila-Jiménez, Laura

2014-01-01

In Mexico, calcaneal ultrasound measurements -bone mineral density (BMD), broadband ultrasound attenuation (BUA), speed of sound (SOS), ultrasonic quantitative index (QUI)- and their differences in regards to menopause have not been documented. It was carried out a cross-sectional study in 862 women from 20 to 90 years old, incorporated through consecutive sample, who were users of the Sistema para el Desarrollo Integral de la Familia (DIF) in Morelos. Sociodemographic, reproductive and life style factors were identified. BMD, BUA, SOS and QUI were measured with quantitative ultrasound (QUS), using a Sunlight Omnisense 7000 S device. Adjusted differences in the mean of these measurements were estimated between pre and postmenopausal women through multiple linear regression. The medians were: BMD, 0.455 g/cm² (IQR, interquartile range = 0.378, 0.538); BUA, 66.0 dB/mHz (IQR = 54.3, 78.1); SOS, 1530.7 m/s (IQR = 1509.8, 1551.7); QUI = 83.7 units (IQR = 71.1, 96.6). In postmenopausal women, adjusted mean for BUA was -4.34 dB/mHz (CI 95 % = -8.23,-0.43); for SOS, -4.26 m/s (CI 95 % = -13.82, 5.30) ; for QUI, -4.42 units (CI 95 % = -8.64,-0.19). This report increases information about the clinical applicability of QUS. SOS in calcaneus does not reflect changes related with menopause.

Repeatability of Doppler ultrasound measurements of hindlimb blood flow in halothane anaesthetised horses.

PubMed

Raisis, A L; Young, L E; Meire, H; Walsh, K; Taylor, P M; Lekeux, P

2000-05-01

The purpose of this study was to determine the repeatability of femoral blood flow recorded using Doppler ultrasound in anaesthetised horses. Doppler ultrasound of the femoral artery and vein was performed in 6 horses anaesthetised with halothane and positioned in left lateral recumbency. Velocity spectra, recorded using low pulse repetition frequency, were used to calculate time-averaged mean velocity (TAV), velocity of component a (TaVa), velocity of component b (TaVb), volumetric flow, early diastolic deceleration slope (EDDS) and pulsatility index (PI). Within-patient variability was determined for sequential Doppler measurements recorded during a single standardised anaesthetic episode. Within-patient variability was also determined for Doppler and cardiovascular measurements recorded during 4 separate standardised anaesthetic episodes performed at intervals of at least one month. Within-patient variation during a single anaesthetic episode was small. Coefficients of variation (cv) were <12.5% for arterial measurements and <17% for venous measurements. Intraclass correlation coefficient was >0.75 for all measurements. No significant change was observed in measurements of cardiovascular function suggesting that within-patient variation observed during a single anaesthetic episode was due to measurement error. In contrast, within-patient variation during 4 separate anaesthetic episodes was marked (cv>17%) for most Doppler measurements obtained from arteries and veins. Variation in measurements of cardiovascular function were marked (cv>20%), suggesting that there is marked biological variation in central and peripheral observed. Further studies are warranted to determine the ability of this technique to detect differences in blood flow during administration of different anaesthetic agents.

The Relationship between Quantitative and Qualitative Measures of Writing Skills.

ERIC Educational Resources Information Center

Howerton, Mary Lou P.; And Others

The relationships of quantitative measures of writing skills to overall writing quality as measured by the E.T.S. Composition Evaluation Scale (CES) were examined. Quantitative measures included indices of language productivity, vocabulary diversity, spelling, and syntactic maturity. Power of specific indices to account for variation in overall…

2D shear-wave ultrasound elastography (SWE) evaluation of ablation zone following radiofrequency ablation of liver lesions: is it more accurate?

PubMed Central

Bo, Xiao W; Li, Xiao L; Guo, Le H; Li, Dan D; Liu, Bo J; Wang, Dan; He, Ya P; Xu, Xiao H

2016-01-01

Objective: To evaluate the usefulness of two-dimensional quantitative ultrasound shear-wave elastography (2D-SWE) [i.e. virtual touch imaging quantification (VTIQ)] in assessing the ablation zone after radiofrequency ablation (RFA) for ex vivo swine livers. Methods: RFA was performed in 10 pieces of fresh ex vivo swine livers with a T20 electrode needle and 20-W output power. Conventional ultrasound, conventional strain elastography (SE) and VTIQ were performed to depict the ablation zone 0 min, 10 min, 30 min and 60 min after ablation. On VTIQ, the ablation zones were evaluated qualitatively by evaluating the shear-wave velocity (SWV) map and quantitatively by measuring the SWV. The ultrasound, SE and VTIQ results were compared against gross pathological and histopathological specimens. Results: VTIQ SWV maps gave more details about the ablation zone, the central necrotic zone appeared as red, lateral necrotic zone as green and transitional zone as light green, from inner to exterior, while the peripheral unablated liver appeared as blue. Conventional ultrasound and SE, however, only marginally depicted the whole ablation zone. The volumes of the whole ablation zone (central necrotic zone + lateral necrotic zone + transitional zone) and necrotic zone (central necrotic zone + lateral necrotic zone) measured by VTIQ showed excellent correlation (r = 0.915, p < 0.001, and 0.856, p = 0.002, respectively) with those by gross pathological specimen, whereas both conventional ultrasound and SE underestimated the volume of the whole ablation zone. The SWV values of the central necrotic zone, lateral necrotic zone, transitional zone and unablated liver parenchyma were 7.54–8.03 m s−1, 5.13–5.28 m s−1, 3.31–3.53 m s−1 and 2.11–2.21 m s−1, respectively (p < 0.001 for all the comparisons). The SWV value for each ablation zone did not change significantly at different observation times within an hour after RFA

Cognitive load predicts point-of-care ultrasound simulator performance.

PubMed

Aldekhyl, Sara; Cavalcanti, Rodrigo B; Naismith, Laura M

2018-02-01

The ability to maintain good performance with low cognitive load is an important marker of expertise. Incorporating cognitive load measurements in the context of simulation training may help to inform judgements of competence. This exploratory study investigated relationships between demographic markers of expertise, cognitive load measures, and simulator performance in the context of point-of-care ultrasonography. Twenty-nine medical trainees and clinicians at the University of Toronto with a range of clinical ultrasound experience were recruited. Participants answered a demographic questionnaire then used an ultrasound simulator to perform targeted scanning tasks based on clinical vignettes. Participants were scored on their ability to both acquire and interpret ultrasound images. Cognitive load measures included participant self-report, eye-based physiological indices, and behavioural measures. Data were analyzed using a multilevel linear modelling approach, wherein observations were clustered by participants. Experienced participants outperformed novice participants on ultrasound image acquisition. Ultrasound image interpretation was comparable between the two groups. Ultrasound image acquisition performance was predicted by level of training, prior ultrasound training, and cognitive load. There was significant convergence between cognitive load measurement techniques. A marginal model of ultrasound image acquisition performance including prior ultrasound training and cognitive load as fixed effects provided the best overall fit for the observed data. In this proof-of-principle study, the combination of demographic and cognitive load measures provided more sensitive metrics to predict ultrasound simulator performance. Performance assessments which include cognitive load can help differentiate between levels of expertise in simulation environments, and may serve as better predictors of skill transfer to clinical practice.

Numerical simulations of clinical focused ultrasound functional neurosurgery

NASA Astrophysics Data System (ADS)

Pulkkinen, Aki; Werner, Beat; Martin, Ernst; Hynynen, Kullervo

2014-04-01

A computational model utilizing grid and finite difference methods were developed to simulate focused ultrasound functional neurosurgery interventions. The model couples the propagation of ultrasound in fluids (soft tissues) and solids (skull) with acoustic and visco-elastic wave equations. The computational model was applied to simulate clinical focused ultrasound functional neurosurgery treatments performed in patients suffering from therapy resistant chronic neuropathic pain. Datasets of five patients were used to derive the treatment geometry. Eight sonications performed in the treatments were then simulated with the developed model. Computations were performed by driving the simulated phased array ultrasound transducer with the acoustic parameters used in the treatments. Resulting focal temperatures and size of the thermal foci were compared quantitatively, in addition to qualitative inspection of the simulated pressure and temperature fields. This study found that the computational model and the simulation parameters predicted an average of 24 ± 13% lower focal temperature elevations than observed in the treatments. The size of the simulated thermal focus was found to be 40 ± 13% smaller in the anterior-posterior direction and 22 ± 14% smaller in the inferior-superior direction than in the treatments. The location of the simulated thermal focus was off from the prescribed target by 0.3 ± 0.1 mm, while the peak focal temperature elevation observed in the measurements was off by 1.6 ± 0.6 mm. Although the results of the simulations suggest that there could be some inaccuracies in either the tissue parameters used, or in the simulation methods, the simulations were able to predict the focal spot locations and temperature elevations adequately for initial treatment planning performed to assess, for example, the feasibility of sonication. The accuracy of the simulations could be improved if more precise ultrasound tissue properties (especially of the

The Prevalence of Osteopenia and Osteoporosis Among Malaysian Type 2 Diabetic Patients Using Quantitative Ultrasound Densitometer

PubMed Central

Abdulameer, Shaymaa Abdalwahed; Sahib, Mohanad Naji; Sulaiman, Syed Azhar Syed

2018-01-01

Background: Type 2 Diabetes Mellitus (T2DM) and osteoporosis are both chronic conditions and the relationship between them is complex. Objective: The aims of this study were to assess the prevalence of Low Bone Mineral density (LBMD, i.e., osteopenia and osteoporosis), as well as, the difference and associations between Quantitative Ultrasound Scan (QUS) parameters with socio-demographic data and clinical related data among T2DM in Penang, Malaysia. Method: An observational, cross-sectional study with a convenient sample of 450 T2DM patients were recruited from the outpatient diabetes clinic at Hospital Pulau Pinang (HPP) to measure Bone Mineral Density (BMD) at the heel bone using QUS. In addition, a self-reported structured questionnaire about the socio-demographic data and osteoporosis risk factors were collected. Moreover, the study included the retrospective collection of clinical data from patients’ medical records. Results: The mean value of T-score for normal BMD, osteopenic and osteoporotic patients’ were (-0.41±0.44), (-1.65±0.39) and (-2.76±0.27), respectively. According to QUS measurements, more than three quarters of T2DM patients (82%) were at high risk of abnormal BMD. The results showed that QUS scores were significantly associated with age, gender, menopausal duration, educational level and diabetic related data. Moreover, the QUS parameters and T-scores demonstrated significant negative correlation with age, menopausal duration, diabetic duration and glycaemic control, as well as, a positive correlation with body mass index and waist to hip ratio. The current study revealed that none of the cardiovascular disease risk factors appear to influence the prevalence of low BMD among T2DM Malaysian patients. Conclusion: The study findings revealed that the assessment of T2DM patients’ bone health and related factor are essential and future educational programs are crucial to improve osteoporosis management. PMID:29755605

Research on respiratory motion correction method based on liver contrast-enhanced ultrasound images of single mode

NASA Astrophysics Data System (ADS)

Zhang, Ji; Li, Tao; Zheng, Shiqiang; Li, Yiyong

2015-03-01

To reduce the effects of respiratory motion in the quantitative analysis based on liver contrast-enhanced ultrasound (CEUS) image sequencesof single mode. The image gating method and the iterative registration method using model image were adopted to register liver contrast-enhanced ultrasound image sequences of single mode. The feasibility of the proposed respiratory motion correction method was explored preliminarily using 10 hepatocellular carcinomas CEUS cases. The positions of the lesions in the time series of 2D ultrasound images after correction were visually evaluated. Before and after correction, the quality of the weighted sum of transit time (WSTT) parametric images were also compared, in terms of the accuracy and spatial resolution. For the corrected and uncorrected sequences, their mean deviation values (mDVs) of time-intensity curve (TIC) fitting derived from CEUS sequences were measured. After the correction, the positions of the lesions in the time series of 2D ultrasound images were almost invariant. In contrast, the lesions in the uncorrected images all shifted noticeably. The quality of the WSTT parametric maps derived from liver CEUS image sequences were improved more greatly. Moreover, the mDVs of TIC fitting derived from CEUS sequences after the correction decreased by an average of 48.48+/-42.15. The proposed correction method could improve the accuracy of quantitative analysis based on liver CEUS image sequences of single mode, which would help in enhancing the differential diagnosis efficiency of liver tumors.

Measuring the volume of uterine fibroids using 2- and 3-dimensional ultrasound and comparison with histopathology.

PubMed

Zivković, Nikica; Zivković, Kreiimir; Despot, Albert; Paić, Josip; Zelić, Ana

2012-12-01

The aim of this study was clinical testing of the reliability and usability of three-dimensional (3D) and two-dimensional (2D) ultrasound (US) technology. The ultimate aim and purpose of this study was to establish ultrasound methods, standards and protocols for determining the volume of any gynecologic organ or tumor. The study included 31 women in reproductive age and postmenopause. All patients were examined with a RIC 5-9 3D-endovaginal probe (4.3-7.5 MHz) on a Voluson 730 Pro ultrasound device. The volume of myomas was measured by using the existing 2D and 3D ultrasound methods on the above mentioned device. All patients underwent myomectomy or hysterectomy due to clinically and ultrasonographically diagnosed uterine myomas indicating operative intervention. After the operation, the pathologist determined the volume of removed myomas by measuring them in a gauge bowl containing water, i.e. using Archimedes' principle (lift), serving as the control group with histopathologic diagnosis. A total of 155 myoma volumes were processed on 2D display, 31 myoma volumes were preoperatively measured on 3D display and 31 myoma volumes were measured by the pathologist. The values of US measurements for each US method were expressed as mean value of all measurements of myoma volumes. Statistical processing of the results and Student's t-test for independent samples revealed that the 2nd examined US method (measuring of myoma by using an ellipse and the longer tumor diameter) and 4th examined US method (measuring of myoma by using the longer and shorter tumor diameters together with establishing their mean values) in 2D US technique, as well as the 6th examined US method in 3D US technique showed no significant measurement differences in comparison with control measurement in a gauge bowl containing water (p < 0.05), indicating acceptability of the US methods for verifying tumor volumes. The standard error in determining the volume of myomas by the above US methods varied

Despeckle filtering software toolbox for ultrasound imaging of the common carotid artery.

PubMed

Loizou, Christos P; Theofanous, Charoula; Pantziaris, Marios; Kasparis, Takis

2014-04-01

Ultrasound imaging of the common carotid artery (CCA) is a non-invasive tool used in medicine to assess the severity of atherosclerosis and monitor its progression through time. It is also used in border detection and texture characterization of the atherosclerotic carotid plaque in the CCA, the identification and measurement of the intima-media thickness (IMT) and the lumen diameter that all are very important in the assessment of cardiovascular disease (CVD). Visual perception, however, is hindered by speckle, a multiplicative noise, that degrades the quality of ultrasound B-mode imaging. Noise reduction is therefore essential for improving the visual observation quality or as a pre-processing step for further automated analysis, such as image segmentation of the IMT and the atherosclerotic carotid plaque in ultrasound images. In order to facilitate this preprocessing step, we have developed in MATLAB(®) a unified toolbox that integrates image despeckle filtering (IDF), texture analysis and image quality evaluation techniques to automate the pre-processing and complement the disease evaluation in ultrasound CCA images. The proposed software, is based on a graphical user interface (GUI) and incorporates image normalization, 10 different despeckle filtering techniques (DsFlsmv, DsFwiener, DsFlsminsc, DsFkuwahara, DsFgf, DsFmedian, DsFhmedian, DsFad, DsFnldif, DsFsrad), image intensity normalization, 65 texture features, 15 quantitative image quality metrics and objective image quality evaluation. The software is publicly available in an executable form, which can be downloaded from http://www.cs.ucy.ac.cy/medinfo/. It was validated on 100 ultrasound images of the CCA, by comparing its results with quantitative visual analysis performed by a medical expert. It was observed that the despeckle filters DsFlsmv, and DsFhmedian improved image quality perception (based on the expert's assessment and the image texture and quality metrics). It is anticipated that the

Preoperative ultrasound measurements predict the feasibility of gallbladder extraction during transgastric natural orifice translumenal endoscopic surgery cholecystectomy.

PubMed

Santos, Byron F; Auyang, Edward D; Hungness, Eric S; Desai, Kush R; Chan, Edward S; van Beek, Darren B; Wang, Edward C; Soper, Nathaniel J

2011-04-01

Extraction of a gallbladder through an endoscopic overtube during natural orifice translumenal endoscopic surgery (NOTES) transgastric cholecystectomy avoids potential injury to the esophagus. This study examined the rate of successful gallbladder specimen extraction through an overtube and hypothesized that preoperative ultrasound findings could predict successful specimen passage. Gallbladder specimens from patients undergoing laparoscopic cholecystectomy were measured, and an attempt was made to pull the specimens through a commercially available overtube with an inner diameter of 16.7-mm. A radiologist blinded to the outcomes reviewed the available preoperative ultrasound measurements from these patients. Ultrasound dimensions including gallbladder length, width, and depth; wall thickness; common bile duct diameter; and size of the largest gallstone (LGS) were recorded. Multiple logistic regression analysis was performed to determine whether ultrasound findings and patient characteristics (age, body mass index [BMI], and sex) could predict the ability of a specimen to pass through the overtube. Of 57 patients, 44 (77%) who had preoperative ultrasounds available for electronic review were included in the final analysis. Gallstones were present in 35 (79%) of these 44 patients. Intraoperative gallbladder perforation occurred in 18 (41%) of the 44 patients, and 16 (36%) of the 44 gallbladders could be extracted through the overtube. Measurement of LGS was possible for 23 patients, and indeterminate gallstone size (IGS) was determined for 12 patients. The rate for passage of perforated versus intact gallbladders was similar (40% vs. 23%; p = 0.054). The LGS (odds ratio [OR], 1.17; 95% confidence interval [CI], 1.02-1.33; p = 0.021) and IGS (OR, 22.97; 95% CI, 1.99-265.63; p = 0.025) predicted failed passage on multivariate logistic regression analysis. The passage rate was 80% for LGS smaller than 10 mm or no stones present, 18% for LGS 10 mm or larger, and 8% for

Comparison of Two Devices for Intraoperative Portal Venous Flow Measurement in Living-Donor Liver Transplantation: Transit Time Ultrasound and Conventional Doppler Ultrasound.

PubMed

Wang, H-K; Chen, C-Y; Lin, N-C; Liu, C-S; Loong, C-C; Lin, Y-H; Lai, Y-C; Chiou, H-J

2018-05-01

Intraoperative portal venous flow measurement provides surgeons with instant guidance for portal flow modulation during living-donor liver transplantation (LDLT). In this study, we compared the agreement of portal flow measurement obtained by 2 devices: transit time ultrasound (TTU) and conventional Doppler ultrasound (CDU). Fifty-four recipients of LDLT underwent intraoperative measurement of portal flow after completion of vascular anastomosis of the implanted partial liver graft. Both TTU and CDU were used concurrently. Agreement of TTU and CDU was assessed by intraclass correlation coefficient using a model of 2-way random effects, absolute agreement, and single measurement. A Bland-Altman plot was applied to assess the variability between the 2 devices. The mean, median, and range of portal venous flow was 1456, 1418, and 117 to 2776 mL/min according to TTU; and 1564, 1566, and 119 to 3216 mL/min according to CDU. The intraclass correlation coefficient of portal venous flow between TTU and CDU was 0.68 (95% confidence interval, 0.51-0.80). The Bland-Altman plots revealed an average variation of 4.8% between TTU and CDU but with a rather wide 95% confidence interval of variation ranging from -57.7% to 67.4%. Intraoperative TTU and CDU showed moderate agreement in portal flow measurement. However, a relatively wide range of variation exists between TTU and CDU, indicating that data obtained from the 2 devices may not be interchangeable. Copyright © 2018 Elsevier Inc. All rights reserved.

Portable bladder ultrasound: an evidence-based analysis.

PubMed

2006-01-01

The aim of this review was to assess the clinical utility of portable bladder ultrasound. TARGET POPULATION AND CONDITION Data from the National Population Health Survey indicate prevalence rates of urinary incontinence are 2.5% in women and 1.4 % in men in the general population. Prevalence of urinary incontinence is higher in women than men and prevalence increases with age. Identified risk factors for urinary incontinence include female gender, increasing age, urinary tract infections (UTI), poor mobility, dementia, smoking, obesity, consuming alcohol and caffeine beverages, physical activity, pregnancy, childbirth, forceps and vacuum-assisted births, episiotomy, abdominal resection for colorectal cancer, and hormone replacement therapy. For the purposes of this review, incontinence populations will be stratified into the following; the elderly, urology patients, postoperative patients, rehabilitation settings, and neurogenic bladder populations. Urinary incontinence is defined as any involuntary leakage of urine. Incontinence can be classified into diagnostic clinical types that are useful in planning evaluation and treatment. The major types of incontinence are stress (physical exertion), urge (overactive bladder), mixed (combined urge and stress urinary incontinence), reflex (neurological impairment of the central nervous system), overflow (leakage due to full bladder), continuous (urinary tract abnormalities), congenital incontinence, and transient incontinence (temporary incontinence). Postvoid residual (PVR) urine volume, which is the amount of urine in the bladder immediately after urination, represents an important component in continence assessment and bladder management to provide quantitative feedback to the patient and continence care team regarding the effectiveness of the voiding technique. Although there is no standardized definition of normal PVR urine volume, measurements greater than 100 mL to 150 mL are considered an indication for urinary

Ultrasound: medical imaging and beyond (an invited review).

PubMed

Azhari, Haim

2012-09-01

Medical applications of ultrasound were first investigated about seventy years ago. It has rapidly evolved since then, becoming an essential tool in medical imaging. Ultrasound ability to provide real time images with frame rates exceeding several hundred frames per second allows one to view rapid anatomical changes as well as to guide minimal invasive procedures. By, combining Doppler techniques with anatomical images ultrasound provides real time quantitative flow information as well. It is portable, versatile, cost effective and considered sufficiently hazardless to monitor pregnancy. Moreover, ultrasound has the unique capacity to offer therapeutic capabilities in addition to its outstanding imaging abilities. It can be used for physiotherapy, lithotripsy, and thermal ablation, and recent studies have demonstrated its usefulness in drug delivery, gene therapy and molecular imaging. The purpose of this article is to provide an introductory review of the field covering briefly topics from basic physics through current imaging methods to therapeutic applications.

Ultrasound pregnancy

MedlinePlus

Pregnancy sonogram; Obstetric ultrasonography; Obstetric sonogram; Ultrasound - pregnancy; IUGR - ultrasound; Intrauterine growth - ultrasound; Polyhydramnios - ultrasound; Oligohydramnios - ultrasound; Placenta previa - ultrasound; Multiple pregnancy - ultrasound; ...

Quantitative contrast-enhanced ultrasound evaluation of pathological complete response in patients with locally advanced breast cancer receiving neoadjuvant chemotherapy.

PubMed

Wan, Cai-Feng; Liu, Xue-Song; Wang, Lin; Zhang, Jie; Lu, Jin-Song; Li, Feng-Hua

2018-06-01

To clarify whether the quantitative parameters of contrast-enhanced ultrasound (CEUS) can be used to predict pathological complete response (pCR) in patients with locally advanced breast cancer receiving neoadjuvant chemotherapy (NAC). Fifty-one patients with histologically proved locally advanced breast cancer scheduled for NAC were enrolled. The quantitative data for CEUS and the tumor diameter were collected at baseline and before surgery, and compared with the pathological response. Multiple logistic regression analysis was performed to examine quantitative parameters at CEUS and the tumor diameter to predict the pCR, and receiver operating characteristic (ROC) curve analysis was used as a summary statistic. Multiple logistic regression analysis revealed that PEAK (the maximum intensity of the time-intensity curve during bolus transit), PEAK%, TTP% (time to peak), and diameter% were significant independent predictors of pCR, and the area under the ROC curve was 0.932(Az 1 ), and the sensitivity and specificity to predict pCR were 93.7% and 80.0%. The area under the ROC curve for the quantitative parameters was 0.927(Az 2 ), and the sensitivity and specificity to predict pCR were 81.2% and 94.3%. For diameter%, the area under the ROC curve was 0.786 (Az 3 ), and the sensitivity and specificity to predict pCR were 93.8% and 54.3%. The values of Az 1 and Az 2 were significantly higher than that of Az 3 (P = 0.027 and P = 0.034, respectively). However, there was no significant difference between the values of Az 1 and Az 2 (P = 0.825). Quantitative analysis of tumor blood perfusion with CEUS is superior to diameter% to predict pCR, and can be used as a functional technique to evaluate tumor response to NAC. Copyright © 2018. Published by Elsevier B.V.

Assessment of a Novel Point-of-Care Ultrasound Curriculum's Effect on Competency Measures in Family Medicine Graduate Medical Education.

PubMed

Bornemann, Paul

2017-06-01

Point-of-care ultrasound has been shown to decrease the use of expensive diagnostic studies and improve quality outcome measures. Currently, there is a large desire for training in family medicine residencies, but very few programs have established curricula. We sought to develop a family medicine residency curriculum and evaluate it with tools we developed. We wanted our curriculum to be easy to adopt by other residency programs, even if they did not have many well-trained ultrasound faculty. We developed a curriculum in the form of a 4-week rotation in a family medicine residency program. It consisted of self-study videos, hands-on training, and image review. We followed residents in postgraduate years 1 to 3 over a 12-month period. We developed tools, including a knowledge exam, to test image interpretation and clinical decision making, an observed structured clinical exam to assess scanning skills, and a survey to assess perceptions of point-of-care ultrasound in family medicine. The assessments were administered before and after each resident's rotation. Seventeen residents completed the rotation. The average knowledge test score improved significantly, from 62 to 84%. The average observed structured clinical exam scores also improved significantly, from 41 to 85%. The average perception survey scores improved slightly from 4.4 to 4.6. We developed a point-of-care ultrasound curriculum for family medicine residency programs that improves measures of resident attitude, skills, and knowledge. This curriculum can be adopted by residency programs with few faculty members who are experienced in ultrasound. © 2017 by the American Institute of Ultrasound in Medicine.

Ultrasound during mid-gestation: Agreement with physical foetal and placental measurements and use in predicting gestational age in sheep.

PubMed

Jones, A K; Gately, R E; McFadden, K K; Hoffman, M L; Pillai, S M; Zinn, S A; Govoni, K E; Reed, S A

2017-08-01

To determine the effects of poor maternal nutrition and litter size on foetal growth during mid-gestation, pregnant ewes (n = 82) were fed 100%, 60% or 140% of NRC TDN beginning at day 30.2 ± 0.2 of gestation. Transabdominal ultrasound was performed weekly between day 46.0 ± 0.4 and 86.0 ± 0.7 to monitor foetal heart width (HW), umbilical diameter (UMB), rib width (RW) and placentome outer (OD) and inner diameter (ID). Data were analysed with repeated-measures using the mixed procedure for effects of maternal diet, litter size and gestation, and equations predictive of gestational age were generated using the regression procedure. To determine the agreement of ultrasound measurement and actual size, ewes (n = 20-21) were euthanized at day 45 or 90 to obtain corresponding postmortem measurements for Bland-Altman analysis. The HW, UMB and placentome OD and ID increased with gestation (p < .0001) but were unaffected by maternal diet or litter size (p ≥ .12). Ultrasound underestimated postmortem measurements of HW (14.8%), UMB (7.3%), placentome OD (4.5%) and ID (37.3%) at day 90 of gestation. Ultrasound underestimated RW at day 45 (7.7%) but overestimated RW (23.8%) at day 90, indicating inconsistent bias when reporting RW by ultrasound. Combining the HW, UMB, RW and placentome OD generated the strongest equation predictive of gestational age (R 2  = .91). These findings indicate that during mid-gestation, maternal diet or litter size did not affect HW, UMB or placentome diameters and these factors can be used to estimate gestational age. © 2017 Blackwell Verlag GmbH.

Evaluation metrics for bone segmentation in ultrasound

NASA Astrophysics Data System (ADS)

Lougheed, Matthew; Fichtinger, Gabor; Ungi, Tamas

2015-03-01

Tracked ultrasound is a safe alternative to X-ray for imaging bones. The interpretation of bony structures is challenging as ultrasound has no specific intensity characteristic of bones. Several image segmentation algorithms have been devised to identify bony structures. We propose an open-source framework that would aid in the development and comparison of such algorithms by quantitatively measuring segmentation performance in the ultrasound images. True-positive and false-negative metrics used in the framework quantify algorithm performance based on correctly segmented bone and correctly segmented boneless regions. Ground-truth for these metrics are defined manually and along with the corresponding automatically segmented image are used for the performance analysis. Manually created ground truth tests were generated to verify the accuracy of the analysis. Further evaluation metrics for determining average performance per slide and standard deviation are considered. The metrics provide a means of evaluating accuracy of frames along the length of a volume. This would aid in assessing the accuracy of the volume itself and the approach to image acquisition (positioning and frequency of frame). The framework was implemented as an open-source module of the 3D Slicer platform. The ground truth tests verified that the framework correctly calculates the implemented metrics. The developed framework provides a convenient way to evaluate bone segmentation algorithms. The implementation fits in a widely used application for segmentation algorithm prototyping. Future algorithm development will benefit by monitoring the effects of adjustments to an algorithm in a standard evaluation framework.

Quantitative force measurements using frequency modulation atomic force microscopy—theoretical foundations

NASA Astrophysics Data System (ADS)

Sader, John E.; Uchihashi, Takayuki; Higgins, Michael J.; Farrell, Alan; Nakayama, Yoshikazu; Jarvis, Suzanne P.

2005-03-01

Use of the atomic force microscope (AFM) in quantitative force measurements inherently requires a theoretical framework enabling conversion of the observed deflection properties of the cantilever to an interaction force. In this paper, the theoretical foundations of using frequency modulation atomic force microscopy (FM-AFM) in quantitative force measurements are examined and rigorously elucidated, with consideration being given to both 'conservative' and 'dissipative' interactions. This includes a detailed discussion of the underlying assumptions involved in such quantitative force measurements, the presentation of globally valid explicit formulae for evaluation of so-called 'conservative' and 'dissipative' forces, discussion of the origin of these forces, and analysis of the applicability of FM-AFM to quantitative force measurements in liquid.

BONE MASS BY QUANTITATIVE ULTRASOUND OF FINGER PHALANGES IN YOUNG KARATE PRACTITIONERS

PubMed Central

Barbeta, Camila Justino de Oliveira; Gonçalves, Ezequiel Moreira; Ribeiro, Keila Donassolo Santos; Ribeiro, Roberto; Roman, Everton Paulo; Guerra-Júnior, Gil

2017-01-01

ABSTRACT Objective: To evaluate bone mass by quantitative ultrasound of the phalanges in young karate practitioners compared to a control group. Methods: Sample composed of 162 karate practitioners (52 females) and 326 healthy controls (110 females) aged 6 to 16 years old, in Western Paraná (Southern Brazil). Weight, height, BMI, amplitude-dependent speed of sound (AD-SoS) and bone transmission time (BTT) were evaluated. BMI, AD-SoS and BTT values were converted to Z scores. Mann-Whitney, chi-square or Fisher Exact tests and multiple linear regression were applied, with significance level set at p≤0.05. Results: Both genders showed higher values of BTT as Z scores when compared to control group. Females from the control group had higher AD-SoS values (m/s and Z score) compared to female karate practitioners. When relative and absolute frequencies were assessed according to BTT Z score in both groups, male karate practitioners’ bone mass was shown to be adequate more frequently. In female practitioners, age and weight were independent predictors of AD-SoS (R2=0.42) and BTT (R2=0.45), respectively. Among male karate practitioners, age was related to 26% of AD-SoS variances and height was responsible for 36% of BTT variances. Conclusions: Children and adolescents who practice karate were shown to have more bone mass in comparison to the control group, regardless of gender. BTT was more sensitive for this evaluation. PMID:28977128

Exploratory Analysis of Carbon Dioxide Levels, Ultrasound and Optical Coherence Tomography Measures of the Eye During ISS Missions

NASA Technical Reports Server (NTRS)

Schaefer, C.; Young, M.; Mason, S.; Coble, C.; Wear, M. L.; Sargsyan, A.; Garcia, K.; Patel, N.; Gibson, C.; Alexander, D.;

Transvaginal ultrasound

MedlinePlus

Endovaginal ultrasound; Ultrasound - transvaginal; Fibroids - transvaginal ultrasound; Vaginal bleeding - transvaginal ultrasound; Uterine bleeding - transvaginal ultrasound; Menstrual bleeding - transvaginal ultrasound; ...

Medical Imaging with Ultrasound: Some Basic Physics.

ERIC Educational Resources Information Center

Gosling, R.

1989-01-01

Discussed are medical applications of ultrasound. The physics of the wave nature of ultrasound including its propagation and production, return by the body, spatial and contrast resolution, attenuation, image formation using pulsed echo ultrasound techniques, measurement of velocity and duplex scanning are described. (YP)

Toward predicting tensile strength of pharmaceutical tablets by ultrasound measurement in continuous manufacturing.

PubMed

Razavi, Sonia M; Callegari, Gerardo; Drazer, German; Cuitiño, Alberto M

2016-06-30

An ultrasound measurement system was employed as a non-destructive method to evaluate its reliability in predicting the tensile strength of tablets and investigate the benefits of incorporating it in a continuous line, manufacturing solid dosage forms. Tablets containing lactose, acetaminophen, and magnesium stearate were manufactured continuously and in batches. The effect of two processing parameters, compaction force and level of shear strain were examined. Young's modulus and tensile strength of tablets were obtained by ultrasound and diametrical mechanical testing, respectively. It was found that as the blend was exposed to increasing levels of shear strain, the speed of sound in the tablets decreased and the tablets became both softer and mechanically weaker. Moreover, the results indicate that two separate tablet material properties (e.g., relative density and Young's modulus) are necessary in order to predict tensile strength. A strategy for hardness prediction is proposed that uses the existing models for Young's modulus and tensile strength of porous materials. Ultrasound testing was found to be very sensitive in differentiating tablets with similar formulation but produced under different processing conditions (e.g., different level of shear strain), thus, providing a fast, and non-destructive method for hardness prediction that could be incorporated to a continuous manufacturing process. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultrasound-guided near-infrared spectroscopy for brain functional study: feasibility analysis and preliminary work

NASA Astrophysics Data System (ADS)

Xu, Ronald; Qiang, Bo; Liu, Jun

2005-04-01

Recent advances in diffuse optical imaging and spectroscopy (DOIS) allow the noninvasive measurement of local changes in cerebral oxygenation and hemodynamics. Available DOIS devices fall into three categories: time domain (TD), frequency domain (FD) and continuous wave (CW). The TD and FD devices have potential for high spatial resolution, high temporal resolution and high accuracy measurement, but the instrument cost and the hardware size prevent their wide clinical application. Furthermore, the presence of the low scattering cerebrospinal fluid layer (CSF) and its thickness variation during motion challenges quantitative, continuous monitoring of the cortex layer oxygenation and blood content. MRI has been used to provide a priori knowledge of the head anatomy that helps the NIR image reconstruction. However, the technology is expensive and lacks portability. This paper proposes a method that combines the accuracy of a TD/FD system and the portability of a CW device. With the optical baseline measured by a TD or FD device and the layer thickness characterized by an ultrasound transducer, a conventional CW system may be able to quantify the cortex layer optical absorption with high accuracy. In this paper, the feasibility of using ultrasound guided CW spectroscopy to monitor brain activities was studied on a multi layer head model using Monte Carlo simulation and order of magnitude analysis. A forward algorithm based on diffuse approximation and 2D Fourier Transform was used to optimize the source detector separation. Both analytical and neuron network approaches were developed for inverse calculation of the cortex layer absorption in real time. An ultrasound transducer was used to monitor the thickness of different layers surrounding the cerebral cortex. The concept of ultrasound guided CW spectroscopy was demonstrated by numerical simulation on a 2 layer head model and the use of the ultrasound transducer for layer thickness characterization was verified by

Quantitative shear wave optical coherence elastography (SW-OCE) with acoustic radiation force impulses (ARFI) induced by phase array transducer

NASA Astrophysics Data System (ADS)

Song, Shaozhen; Le, Nhan Minh; Wang, Ruikang K.; Huang, Zhihong

2015-03-01

Shear Wave Optical Coherence Elastography (SW-OCE) uses the speed of propagating shear waves to provide a quantitative measurement of localized shear modulus, making it a valuable technique for the elasticity characterization of tissues such as skin and ocular tissue. One of the main challenges in shear wave elastography is to induce a reliable source of shear wave; most of nowadays techniques use external vibrators which have several drawbacks such as limited wave propagation range and/or difficulties in non-invasive scans requiring precisions, accuracy. Thus, we propose linear phase array ultrasound transducer as a remote wave source, combined with the high-speed, 47,000-frame-per-second Shear-wave visualization provided by phase-sensitive OCT. In this study, we observed for the first time shear waves induced by a 128 element linear array ultrasound imaging transducer, while the ultrasound and OCT images (within the OCE detection range) were triggered simultaneously. Acoustic radiation force impulses are induced by emitting 10 MHz tone-bursts of sub-millisecond durations (between 50 μm - 100 μm). Ultrasound beam steering is achieved by programming appropriate phase delay, covering a lateral range of 10 mm and full OCT axial (depth) range in the imaging sample. Tissue-mimicking phantoms with agarose concentration of 0.5% and 1% was used in the SW-OCE measurements as the only imaging samples. The results show extensive improvements over the range of SW-OCE elasticity map; such improvements can also be seen over shear wave velocities in softer and stiffer phantoms, as well as determining the boundary of multiple inclusions with different stiffness. This approach opens up the feasibility to combine medical ultrasound imaging and SW-OCE for high-resolution localized quantitative measurement of tissue biomechanical property.

Is uterine depth measurement by trans-vaginal ultrasound alone as accurate as measurement carried out by trans-abdominal ultrasound-guided trial transfer?

PubMed

Edris, Fawaz E

2014-10-01

To assess the reliability of trans-vaginal-scan (TVS) in measuring the uterine depth (UD) in comparison with ultrasound-guided trial-transfer (UTT). This prospective study was conducted in 66 consecutive patients undergoing in-vitro fertilization and embryo transfer (IVF-ET). The study took place in a private IVF center in Jeddah, Saudi Arabia between November 2013 and January 2014. The patients underwent UD measurements using TVS and UTT, sequentially. All scans were performed by a single sonographer, and all UTT were carried out by a single physician who was blinded to the TVS measurement. The median (95% confidence interval) UD measurement using the TVS method was 6.9 cm (5.0-12.5) and UTT was 7.1 cm (5.9-13.5), (p<0.0001). Fifteen patients (22.7%) had a difference of >1 cm between the 2 measurement modalities (group-B). When measured by UTT, 93.3% of patients in group-B had UD >/-8cm, compared with 9.8% of patients in group-A, (p<0.0001). Group-B had a significantly longer uterine cavity when measured by UTT (p<0.0001), and a trend towards significance when measured by TVS (p=0.055). The TVS measurements generally underestimated UD when compared with UTT. Trans-vaginal-scan is less reliable than UTT and should not be used as a substitute. Larger sample-size studies involving different personnel, and equipment is needed. 

Fetal growth and air pollution - A study on ultrasound and birth measures.

PubMed

Malmqvist, Ebba; Liew, Zeyan; Källén, Karin; Rignell-Hydbom, Anna; Rittner, Ralf; Rylander, Lars; Ritz, Beate

2017-01-01

Air pollution has been suggested to affect fetal growth, but more data is needed to assess the timing of exposure effects by using ultrasound measures. It is also important to study effects in low exposure areas to assess eventual thresholds of effects. The MAPSS (Maternal Air Pollution in Southern Sweden) cohort consists of linked registry data for around 48,000 pregnancies from an ultrasound database, birth registry and exposure data based on residential addresses. Measures of air pollution exposure were obtained through dispersion modelling with input data from an emissions database (NO x ) with high resolution (100-500m grids). Air pollution effects were assessed with linear regressions for the following endpoints; biparietal diameter, femur length, abdominal diameter and estimated fetal weight measured in late pregnancy and birth weight and head circumference measured at birth. We estimated negative effects for NO x ; in the adjusted analyses the decrease of abdominal diameter and femur length were -0.10 (-0.17, -0.03) and -0.13 (-0.17, -0.01)mm, respectively, per 10µg/m 3 increment of NO x . We also estimated an effect of NO x -exposures on birth weight by reducing birth weight by 9g per 10µg/m 3 increment of NO x . We estimated small but statistically significant effects of air pollution on late fetal and birth size and reduced fetal growth late in pregnancy in a geographic area with levels below current WHO air quality guidelines. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

A new fringeline-tracking approach for color Doppler ultrasound imaging phase unwrapping

NASA Astrophysics Data System (ADS)

Saad, Ashraf A.; Shapiro, Linda G.

2008-03-01

Color Doppler ultrasound imaging is a powerful non-invasive diagnostic tool for many clinical applications that involve examining the anatomy and hemodynamics of human blood vessels. These clinical applications include cardio-vascular diseases, obstetrics, and abdominal diseases. Since its commercial introduction in the early eighties, color Doppler ultrasound imaging has been used mainly as a qualitative tool with very little attempts to quantify its images. Many imaging artifacts hinder the quantification of the color Doppler images, the most important of which is the aliasing artifact that distorts the blood flow velocities measured by the color Doppler technique. In this work we will address the color Doppler aliasing problem and present a recovery methodology for the true flow velocities from the aliased ones. The problem is formulated as a 2D phase-unwrapping problem, which is a well-defined problem with solid theoretical foundations for other imaging domains, including synthetic aperture radar and magnetic resonance imaging. This paper documents the need for a phase unwrapping algorithm for use in color Doppler ultrasound image analysis. It describes a new phase-unwrapping algorithm that relies on the recently developed cutline detection approaches. The algorithm is novel in its use of heuristic information provided by the ultrasound imaging modality to guide the phase unwrapping process. Experiments have been performed on both in-vitro flow-phantom data and in-vivo human blood flow data. Both data types were acquired under a controlled acquisition protocol developed to minimize the distortion of the color Doppler data and hence to simplify the phase-unwrapping task. In addition to the qualitative assessment of the results, a quantitative assessment approach was developed to measure the success of the results. The results of our new algorithm have been compared on ultrasound data to those from other well-known algorithms, and it outperforms all of them.

Three-dimensional segmentation of luminal and adventitial borders in serial intravascular ultrasound images

NASA Technical Reports Server (NTRS)

Shekhar, R.; Cothren, R. M.; Vince, D. G.; Chandra, S.; Thomas, J. D.; Cornhill, J. F.

1999-01-01

Intravascular ultrasound (IVUS) provides exact anatomy of arteries, allowing accurate quantitative analysis. Automated segmentation of IVUS images is a prerequisite for routine quantitative analyses. We present a new three-dimensional (3D) segmentation technique, called active surface segmentation, which detects luminal and adventitial borders in IVUS pullback examinations of coronary arteries. The technique was validated against expert tracings by computing correlation coefficients (range 0.83-0.97) and William's index values (range 0.37-0.66). The technique was statistically accurate, robust to image artifacts, and capable of segmenting a large number of images rapidly. Active surface segmentation enabled geometrically accurate 3D reconstruction and visualization of coronary arteries and volumetric measurements.

Ultrasound

MedlinePlus

... community Home > Pregnancy > Prenatal care > Ultrasound during pregnancy Ultrasound during pregnancy E-mail to a friend Please ... you. What are some reasons for having an ultrasound? Your provider uses ultrasound to do several things, ...

Ultrasound and polar homogeneous reactions.

PubMed

Tuulmets, A

1997-04-01

The effect of ultrasound on the rates of homogeneous heterolytic reactions not switched to a free radical pathway can be explained by the perturbation of the molecular organization of or the solvation in the reacting system. A quantitative analysis of the sonochemical acceleration on the basis of the microreactor concept was carried out. It was found that (1) the Diels-Alder reaction cannot be accelerated by ultrasound except when SET or free radical processes are promoted, (2) the rectified diffusion during cavitation cannot be responsible for the acceleration of reactions, and (3) the sonochemical acceleration of polar homogeneous reactions takes place in the bulk reaction medium. This implies the presence of a 'sound-field' sonochemistry besides the 'hot-spot' sonochemistry. The occurrence of a sonochemical deceleration effect can be predicted.

Smile line assessment comparing quantitative measurement and visual estimation.

PubMed

Van der Geld, Pieter; Oosterveld, Paul; Schols, Jan; Kuijpers-Jagtman, Anne Marie

2011-02-01

Esthetic analysis of dynamic functions such as spontaneous smiling is feasible by using digital videography and computer measurement for lip line height and tooth display. Because quantitative measurements are time-consuming, digital videography and semiquantitative (visual) estimation according to a standard categorization are more practical for regular diagnostics. Our objective in this study was to compare 2 semiquantitative methods with quantitative measurements for reliability and agreement. The faces of 122 male participants were individually registered by using digital videography. Spontaneous and posed smiles were captured. On the records, maxillary lip line heights and tooth display were digitally measured on each tooth and also visually estimated according to 3-grade and 4-grade scales. Two raters were involved. An error analysis was performed. Reliability was established with kappa statistics. Interexaminer and intraexaminer reliability values were high, with median kappa values from 0.79 to 0.88. Agreement of the 3-grade scale estimation with quantitative measurement showed higher median kappa values (0.76) than the 4-grade scale estimation (0.66). Differentiating high and gummy smile lines (4-grade scale) resulted in greater inaccuracies. The estimation of a high, average, or low smile line for each tooth showed high reliability close to quantitative measurements. Smile line analysis can be performed reliably with a 3-grade scale (visual) semiquantitative estimation. For a more comprehensive diagnosis, additional measuring is proposed, especially in patients with disproportional gingival display. Copyright © 2011 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Assessment of tumor response to radiation and vascular targeting therapy in mice using quantitative ultrasound spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

El Kaffas, Ahmed; Sadeghi-Naini, Ali; Falou, Omar

Purpose: It is now recognized that the tumor vasculature is in part responsible for regulating tumor responses to radiation therapy. However, the extent to which radiation-based vascular damage contributes to tumor cell death remains unknown. In this work, quantitative ultrasound spectroscopy (QUS) methods were used to investigate the acute responses of tumors to radiation-based vascular treatments. Methods: Tumor xenografts (MDA-MB-231) were treated with single radiation doses of 2 or 8 Gy alone, or in combination with pharmacological agents that modulate vascular radiosensitivity. The midband fit, the slope, and the 0-MHz intercept QUS parameters were obtained from a linear-regression fit tomore » the averaged power spectrum of frequency-dependent ultrasound backscatter and were used to quantify acute tumor responses following treatment administration. Power spectrums were extracted from raw volumetric radio-frequency ultrasound data obtained before and 24 h following treatment administration. These parameters have previously been correlated to tumor cell death. Staining using in situ end labeling, carbonic anhydrase 9 and cluster of differentiation 31 of tumor sections were used to assess cell death, oxygenation, and vasculature distributions, respectively. Results: Results indicate a significant midband fit QUS parameter increases of 3.2 ± 0.3 dBr and 5.4 ± 0.5 dBr for tumors treated with 2 and 8 Gy radiation combined with the antiangiogenic agent Sunitinib, respectively. In contrast, tumors treated with radiation alone demonstrated a significant midband fit increase of 4.4 ± 0.3 dBr at 8 Gy only. Preadministration of basic fibroblast growth factor, an endothelial radioprotector, acted to minimize tumor response following single large doses of radiation. Immunohistochemical analysis was in general agreement with QUS findings; an R{sup 2} of 0.9 was observed when quantified cell death was correlated with changes in midband fit. Conclusions: Results from QUS

Acoustic characterization of high intensity focused ultrasound fields: A combined measurement and modeling approach

PubMed Central

Canney, Michael S.; Bailey, Michael R.; Crum, Lawrence A.; Khokhlova, Vera A.; Sapozhnikov, Oleg A.

2008-01-01

Acoustic characterization of high intensity focused ultrasound (HIFU) fields is important both for the accurate prediction of ultrasound induced bioeffects in tissues and for the development of regulatory standards for clinical HIFU devices. In this paper, a method to determine HIFU field parameters at and around the focus is proposed. Nonlinear pressure waveforms were measured and modeled in water and in a tissue-mimicking gel phantom for a 2 MHz transducer with an aperture and focal length of 4.4 cm. Measurements were performed with a fiber optic probe hydrophone at intensity levels up to 24 000 W∕cm2. The inputs to a Khokhlov–Zabolotskaya–Kuznetsov-type numerical model were determined based on experimental low amplitude beam plots. Strongly asymmetric waveforms with peak positive pressures up to 80 MPa and peak negative pressures up to 15 MPa were obtained both numerically and experimentally. Numerical simulations and experimental measurements agreed well; however, when steep shocks were present in the waveform at focal intensity levels higher than 6000 W∕cm2, lower values of the peak positive pressure were observed in the measured waveforms. This underrepresentation was attributed mainly to the limited hydrophone bandwidth of 100 MHz. It is shown that a combination of measurements and modeling is necessary to enable accurate characterization of HIFU fields. PMID:19062878

Effect of modulated ultrasound parameters on ultrasound-induced thrombolysis.

PubMed

Soltani, Azita; Volz, Kim R; Hansmann, Doulas R

2008-12-07

The potential of ultrasound to enhance enzyme-mediated thrombolysis by application of constant operating parameters (COP) has been widely demonstrated. In this study, the effect of ultrasound with modulated operating parameters (MOP) on enzyme-mediated thrombolysis was investigated. The MOP protocol was applied to an in vitro model of thrombolysis. The results were compared to a COP with the equivalent soft tissue thermal index (TIS) over the duration of ultrasound exposure of 30 min (p < 0.14). To explore potential differences in the mechanism responsible for ultrasound-induced thrombolysis, a perfusion model was used to measure changes in average fibrin pore size of clot before, after and during exposure to MOP and COP protocols and cavitational activity was monitored in real time for both protocols using a passive cavitation detection system. The relative lysis enhancement by each COP and MOP protocol compared to alteplase alone yielded values of 33.69 +/- 12.09% and 63.89 +/- 15.02% in a thrombolysis model, respectively (p < 0.007). Both COP and MOP protocols caused an equivalent significant increase in average clot pore size of 2.09 x 10(-2) +/- 0.01 microm and 1.99 x 10(-2) +/- 0.004 microm, respectively (p < 0.74). No signatures of inertial or stable cavitation were observed for either acoustic protocol. In conclusion, due to mechanisms other than cavitation, application of ultrasound with modulated operating parameters has the potential to significantly enhance the relative lysis enhancement compared to application of ultrasound with constant operating parameters.

Feasibility of A-mode ultrasound attenuation as a monitoring method of local hyperthermia treatment.

PubMed

Manaf, Noraida Abd; Aziz, Maizatul Nadwa Che; Ridzuan, Dzulfadhli Saffuan; Mohamad Salim, Maheza Irna; Wahab, Asnida Abd; Lai, Khin Wee; Hum, Yan Chai

2016-06-01

Recently, there is an increasing interest in the use of local hyperthermia treatment for a variety of clinical applications. The desired therapeutic outcome in local hyperthermia treatment is achieved by raising the local temperature to surpass the tissue coagulation threshold, resulting in tissue necrosis. In oncology, local hyperthermia is used as an effective way to destroy cancerous tissues and is said to have the potential to replace conventional treatment regime like surgery, chemotherapy or radiotherapy. However, the inability to closely monitor temperature elevations from hyperthermia treatment in real time with high accuracy continues to limit its clinical applicability. Local hyperthermia treatment requires real-time monitoring system to observe the progression of the destroyed tissue during and after the treatment. Ultrasound is one of the modalities that have great potential for local hyperthermia monitoring, as it is non-ionizing, convenient and has relatively simple signal processing requirement compared to magnetic resonance imaging and computed tomography. In a two-dimensional ultrasound imaging system, changes in tissue microstructure during local hyperthermia treatment are observed in terms of pixel value analysis extracted from the ultrasound image itself. Although 2D ultrasound has shown to be the most widely used system for monitoring hyperthermia in ultrasound imaging family, 1D ultrasound on the other hand could offer a real-time monitoring and the method enables quantitative measurement to be conducted faster and with simpler measurement instrument. Therefore, this paper proposes a new local hyperthermia monitoring method that is based on one-dimensional ultrasound. Specifically, the study investigates the effect of ultrasound attenuation in normal and pathological breast tissue when the temperature in tissue is varied between 37 and 65 °C during local hyperthermia treatment. Besides that, the total protein content measurement was also

A high pulse repetition frequency ultrasound system for the ex vivo measurement of mechanical properties of crystalline lenses with laser-induced microbubbles interrogated by acoustic radiation force.

PubMed

Yoon, Sangpil; Aglyamov, Salavat; Karpiouk, Andrei; Emelianov, Stanislav

2012-08-07

A high pulse repetition frequency ultrasound system for an ex vivo measurement of mechanical properties of an animal crystalline lens was developed and validated. We measured the bulk displacement of laser-induced microbubbles created at different positions within the lens using nanosecond laser pulses. An impulsive acoustic radiation force was applied to the microbubble, and spatio-temporal measurements of the microbubble displacement were assessed using a custom-made high pulse repetition frequency ultrasound system consisting of two 25 MHz focused ultrasound transducers. One of these transducers was used to emit a train of ultrasound pulses and another transducer was used to receive the ultrasound echoes reflected from the microbubble. The developed system was operating at 1 MHz pulse repetition frequency. Based on the measured motion of the microbubble, Young's moduli of surrounding tissue were reconstructed and the values were compared with those measured using the indentation test. Measured values of Young's moduli of four bovine lenses ranged from 2.6 ± 0.1 to 26 ± 1.4 kPa, and there was good agreement between the two methods. Therefore, our studies, utilizing the high pulse repetition frequency ultrasound system, suggest that the developed approach can be used to assess the mechanical properties of ex vivo crystalline lenses. Furthermore, the potential of the presented approach for in vivo measurements is discussed.

Evaluation of airway protection: Quantitative timing measures versus penetration/aspiration score.

PubMed

Kendall, Katherine A

2017-10-01

Quantitative measures of swallowing function may improve the reliability and accuracy of modified barium swallow (MBS) study interpretation. Quantitative study analysis has not been widely instituted, however, secondary to concerns about the time required to make measures and a lack of research demonstrating impact on MBS interpretation. This study compares the accuracy of the penetration/aspiration (PEN/ASP) scale (an observational visual-perceptual assessment tool) to quantitative measures of airway closure timing relative to the arrival of the bolus at the upper esophageal sphincter in identifying a failure of airway protection during deglutition. Retrospective review of clinical swallowing data from a university-based outpatient clinic. Swallowing data from 426 patients were reviewed. Patients with normal PEN/ASP scores were identified, and the results of quantitative airway closure timing measures for three liquid bolus sizes were evaluated. The incidence of significant airway closure delay with and without a normal PEN/ASP score was determined. Inter-rater reliability for the quantitative measures was calculated. In patients with a normal PEN/ASP score, 33% demonstrated a delay in airway closure on at least one swallow during the MBS study. There was no correlation between PEN/ASP score and airway closure delay. Inter-rater reliability for the quantitative measure of airway closure timing was nearly perfect (intraclass correlation coefficient = 0.973). The use of quantitative measures of swallowing function, in conjunction with traditional visual perceptual methods of MBS study interpretation, improves the identification of airway closure delay, and hence, potential aspiration risk, even when no penetration or aspiration is apparent on the MBS study. 4. Laryngoscope, 127:2314-2318, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

Quantitative endoscopy: initial accuracy measurements.

PubMed

Truitt, T O; Adelman, R A; Kelly, D H; Willging, J P

2000-02-01

The geometric optics of an endoscope can be used to determine the absolute size of an object in an endoscopic field without knowing the actual distance from the object. This study explores the accuracy of a technique that estimates absolute object size from endoscopic images. Quantitative endoscopy involves calibrating a rigid endoscope to produce size estimates from 2 images taken with a known traveled distance between the images. The heights of 12 samples, ranging in size from 0.78 to 11.80 mm, were estimated with this calibrated endoscope. Backup distances of 5 mm and 10 mm were used for comparison. The mean percent error for all estimated measurements when compared with the actual object sizes was 1.12%. The mean errors for 5-mm and 10-mm backup distances were 0.76% and 1.65%, respectively. The mean errors for objects <2 mm and > or =2 mm were 0.94% and 1.18%, respectively. Quantitative endoscopy estimates endoscopic image size to within 5% of the actual object size. This method remains promising for quantitatively evaluating object size from endoscopic images. It does not require knowledge of the absolute distance of the endoscope from the object, rather, only the distance traveled by the endoscope between images.

Indium adhesion provides quantitative measure of surface cleanliness

NASA Technical Reports Server (NTRS)

Krieger, G. L.; Wilson, G. J.

1968-01-01

Indium tipped probe measures hydrophobic and hydrophilic contaminants on rough and smooth surfaces. The force needed to pull the indium tip, which adheres to a clean surface, away from the surface provides a quantitative measure of cleanliness.

AMH MEASUREMENT VERSUS OVARIAN ULTRASOUND IN THE DIAGNOSIS OF POLYCYSTIC OVARY SYNDROME IN DIFFERENT PHENOTYPES.

PubMed

Carmina, Enrico; Campagna, Anna M; Fruzzetti, Franca; Lobo, Rogerio A

2016-03-01

This study was designed to assess the value of serum anti-Müllerian hormone (AMH) in the diagnosis of polycystic ovary syndrome (PCOS) in various phenotypes and to assess ovarian ultrasound parameters. We performed a retrospective matched controlled study of 113 females with various PCOS phenotypes and 47 matched controls. The diagnostic utility of AMH measurement and ovarian ultrasound were compared. Using receiver operating characteristic (ROC) curve analyses, the threshold for AMH (>4.7 ng/mL) and ultrasound parameters (follicle number per ovary [FNPO] >22 and ovarian volume [OV] >8 cc) were established. In the entire cohort, AMH had a low sensitivity of 79%; while FNPO and OV were 93% and 68%, respectively. Specificities ranged from 85 to 96%. In classic anovulatory PCOS, AMH exhibited a sensitivity of 91%, and for FNPO and OV the corresponding sensitivities were 92% and 72%. In the ovulatory phenotype, AMH sensitivity was only 50%, while FNPO and OV were 95% and 50%, respectively. In the nonhyperandrogenic phenotype, the sensitivity of AMH was 53% while those for FNPO and OV were 93% and 67%. AMH does not appear to be helpful for all subjects with PCOS but may be of some value in those who are anovulatory. However, FNPO was highly sensitive in all phenotypes, and was the single best criterion assessed for all subjects, suggesting the important role of ultrasound.

A step towards measuring the fetal head circumference with the use of obstetric ultrasound in a low resource setting

NASA Astrophysics Data System (ADS)

van den Heuvel, Thomas L. A.; Petros, Hezkiel; Santini, Stefano; de Korte, Chris L.; van Ginneken, Bram

2017-03-01

Worldwide, 99% of all maternal deaths occur in low-resource countries. Ultrasound imaging can be used to detect maternal risk factors, but requires a well-trained sonographer to obtain the biometric parameters of the fetus. One of the most important biometric parameters is the fetal Head Circumference (HC). The HC can be used to estimate the Gestational Age (GA) and assess the growth of the fetus. In this paper we propose a method to estimate the fetal HC with the use of the Obstetric Sweep Protocol (OSP). With the OSP the abdomen of pregnant women is imaged with the use of sweeps. These sweeps can be taught to somebody without any prior knowledge of ultrasound within a day. Both the OSP and the standard two-dimensional ultrasound image for HC assessment were acquired by an experienced gynecologist from fifty pregnant women in St. Luke's Hospital in Wolisso, Ethiopia. The reference HC from the standard two-dimensional ultrasound image was compared to both the manually measured HC and the automatically measured HC from the OSP data. The median difference between the estimated GA from the manual measured HC using the OSP and the reference standard was -1.1 days (Median Absolute Deviation (MAD) 7.7 days). The median difference between the estimated GA from the automatically measured HC using the OSP and the reference standard was -6.2 days (MAD 8.6 days). Therefore, it can be concluded that it is possible to estimate the fetal GA with simple obstetric sweeps with a deviation of only one week.

Ultrasound Metrology in Mexico: a round robin test for medical diagnostics

NASA Astrophysics Data System (ADS)

Amezola Luna, R.; López Sánchez, A. L.; Elías Juárez, A. A.

2011-02-01

This paper presents preliminary statistical results from an on-going imaging medical ultrasound study, of particular relevance for gynecology and obstetrics areas. Its scope is twofold, firstly to compile the medical ultrasound infrastructure available in cities of Queretaro-Mexico, and second to promote the use of traceable measurement standards as a key aspect to assure quality of ultrasound examinations performed by medical specialists. The experimental methodology is based on a round robin test using an ultrasound phantom for medical imaging. The physician, using its own ultrasound machine, couplant and facilities, measures the size and depth of a set of pre-defined reflecting and absorbing targets of the reference phantom, which simulate human illnesses. Measurements performed give the medical specialist an objective feedback regarding some performance characteristics of their ultrasound examination systems, such as measurement system accuracy, dead zone, axial resolution, depth of penetration and anechoic targets detection. By the end of March 2010, 66 entities with medical ultrasound facilities, from both public and private institutions, have performed measurements. A network of medical ultrasound calibration laboratories in Mexico, with traceability to The International System of Units via national measurement standards, may indeed contribute to reduce measurement deviations and thus attain better diagnostics.

"I Thought My Heart Would Burst": The Role of Ultrasound Technology on Expectant Grandmotherhood

ERIC Educational Resources Information Center

Harpel, Tammy S.; Hertzog, Jodie

2010-01-01

Using both quantitative and qualitative data, this study investigates the role of ultrasound technology on feelings of attachment and emotions experienced by expectant grandmothers. A total of 109 expectant grandmothers complete the 84-question Web-based survey. A 12-item scale is used to assess the impact of ultrasound on attachment. As expected,…

Elasticity mapping of tissue mimicking phantoms by remote palpation with a focused ultrasound beam and intensity autocorrelation measurements

NASA Astrophysics Data System (ADS)

Usha Devi, C.; Bharat Chandran, R. S.; Vasu, R. M.; Sood, A. K.

2007-05-01

We use a focused ultrasound beam to load a region of interest (ROI) in a tissue-mimicking phantom and read out the vibration amplitude of phantom particles from the modulation depth in the intensity autocorrelation of a coherent light beam that intercepted the ROI. The modulation depth, which is also affected by the local light absorption coefficient, which is employed in ultrasound assisted optical tomography, to read out absorption coefficient is greatly influenced by the vibration amplitude, depends to a great extend on local elasticity. We scan a plane in an elastography phantom with an inhomogeneous inclusion, in elasticity with the focused ultrasound and from the measured modulation depth variation create a qualitative map of the elasticity variation in the interrogated plane.

Quantitative tomographic measurements of opaque multiphase flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

GEORGE,DARIN L.; TORCZYNSKI,JOHN R.; SHOLLENBERGER,KIM ANN

2000-03-01

An electrical-impedance tomography (EIT) system has been developed for quantitative measurements of radial phase distribution profiles in two-phase and three-phase vertical column flows. The EIT system is described along with the computer algorithm used for reconstructing phase volume fraction profiles. EIT measurements were validated by comparison with a gamma-densitometry tomography (GDT) system. The EIT system was used to accurately measure average solid volume fractions up to 0.05 in solid-liquid flows, and radial gas volume fraction profiles in gas-liquid flows with gas volume fractions up to 0.15. In both flows, average phase volume fractions and radial volume fraction profiles from GDTmore » and EIT were in good agreement. A minor modification to the formula used to relate conductivity data to phase volume fractions was found to improve agreement between the methods. GDT and EIT were then applied together to simultaneously measure the solid, liquid, and gas radial distributions within several vertical three-phase flows. For average solid volume fractions up to 0.30, the gas distribution for each gas flow rate was approximately independent of the amount of solids in the column. Measurements made with this EIT system demonstrate that EIT may be used successfully for noninvasive, quantitative measurements of dispersed multiphase flows.« less

Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography

PubMed Central

Yeo, Joon Hyung; Moon, Nam Ju

2017-01-01

Purpose To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography. Methods Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa was measured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominant eye was compared with measurements by Orbscan II. Results The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was 3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p < 0.001). The two methods showed good reliability (intraclass correlation coefficient, 0.671; p < 0.001). Bland-Altman plots were used to demonstrate the agreement between the two methods. Conclusions We designed a new method using UBM and corneal topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device. PMID:28471103

Measurement of Angle Kappa Using Ultrasound Biomicroscopy and Corneal Topography.

PubMed

Yeo, Joon Hyung; Moon, Nam Ju; Lee, Jeong Kyu

2017-06-01

To introduce a new convenient and accurate method to measure the angle kappa using ultrasound biomicroscopy (UBM) and corneal topography. Data from 42 eyes (13 males and 29 females) were analyzed in this study. The angle kappa was measured using Orbscan II and calculated with UBM and corneal topography. The angle kappa of the dominant eye was compared with measurements by Orbscan II. The mean patient age was 36.4 ± 13.8 years. The average angle kappa measured by Orbscan II was 3.98° ± 1.12°, while the average angle kappa calculated with UBM and corneal topography was 3.19° ± 1.15°. The difference in angle kappa measured by the two methods was statistically significant (p < 0.001). The two methods showed good reliability (intraclass correlation coefficient, 0.671; p < 0.001). Bland-Altman plots were used to demonstrate the agreement between the two methods. We designed a new method using UBM and corneal topography to calculate the angle kappa. This method is convenient to use and allows for measurement of the angle kappa without an expensive device. © 2017 The Korean Ophthalmological Society

Ultrasound-based quantification of vitreous floaters correlates with contrast sensitivity and quality of life.

PubMed

Mamou, Jonathan; Wa, Christianne A; Yee, Kenneth M P; Silverman, Ronald H; Ketterling, Jeffrey A; Sadun, Alfredo A; Sebag, J

2015-01-22

Clinical evaluation of floaters lacks quantitative assessment of vitreous structure. This study used quantitative ultrasound (QUS) to measure vitreous opacities. Since floaters reduce contrast sensitivity (CS) and quality of life (Visual Function Questionnaire [VFQ]), it is hypothesized that QUS will correlate with CS and VFQ in patients with floaters. Twenty-two eyes (22 subjects; age = 57 ± 19 years) with floaters were evaluated with Freiburg acuity contrast testing (FrACT; %Weber) and VFQ. Ultrasonography used a customized probe (15-MHz center frequency, 20-mm focal length, 7-mm aperture) with longitudinal and transverse scans taken in primary gaze and a horizontal longitudinal scan through premacular vitreous in temporal gaze. Each scan set had 100 frames of log-compressed envelope data. Within each frame, two regions of interest (ROIs) were analyzed (whole-central and posterior vitreous) to yield three parameters (energy, E; mean amplitude, M; and percentage of vitreous filled by echodensities, P50) averaged over the entire 100-frame dataset. Statistical analyses evaluated E, M, and P50 correlations with CS and VFQ. Contrast sensitivity ranged from 1.19%W (normal) to 5.59%W. All QUS parameters in two scan positions within the whole-central ROI correlated with CS (R > 0.67, P < 0.001). P50 in the nasal longitudinal position had R = 0.867 (P < 0.001). Correlations with VFQ ranged from R = 0.52 (P < 0.013) to R = 0.65 (P < 0.001). Quantitative ultrasound provides quantitative measures of vitreous echodensity that correlate with CS and VFQ, providing objective assessment of vitreous structure underlying the functional disturbances induced by floaters, useful to quantify vitreous disease severity and the response to therapy. Copyright 2015 The Association for Research in Vision and Ophthalmology, Inc.

Ultrasound-Based Quantification of Vitreous Floaters Correlates with Contrast Sensitivity and Quality of Life

PubMed Central

Mamou, Jonathan; Wa, Christianne A.; Yee, Kenneth M. P.; Silverman, Ronald H.; Ketterling, Jeffrey A.; Sadun, Alfredo A.; Sebag, J.

2015-01-01

Purpose. Clinical evaluation of floaters lacks quantitative assessment of vitreous structure. This study used quantitative ultrasound (QUS) to measure vitreous opacities. Since floaters reduce contrast sensitivity (CS) and quality of life (Visual Function Questionnaire [VFQ]), it is hypothesized that QUS will correlate with CS and VFQ in patients with floaters. Methods. Twenty-two eyes (22 subjects; age = 57 ± 19 years) with floaters were evaluated with Freiburg acuity contrast testing (FrACT; %Weber) and VFQ. Ultrasonography used a customized probe (15-MHz center frequency, 20-mm focal length, 7-mm aperture) with longitudinal and transverse scans taken in primary gaze and a horizontal longitudinal scan through premacular vitreous in temporal gaze. Each scan set had 100 frames of log-compressed envelope data. Within each frame, two regions of interest (ROIs) were analyzed (whole-central and posterior vitreous) to yield three parameters (energy, E; mean amplitude, M; and percentage of vitreous filled by echodensities, P50) averaged over the entire 100-frame dataset. Statistical analyses evaluated E, M, and P50 correlations with CS and VFQ. Results. Contrast sensitivity ranged from 1.19%W (normal) to 5.59%W. All QUS parameters in two scan positions within the whole-central ROI correlated with CS (R > 0.67, P < 0.001). P50 in the nasal longitudinal position had R = 0.867 (P < 0.001). Correlations with VFQ ranged from R = 0.52 (P < 0.013) to R = 0.65 (P < 0.001). Conclusions. Quantitative ultrasound provides quantitative measures of vitreous echodensity that correlate with CS and VFQ, providing objective assessment of vitreous structure underlying the functional disturbances induced by floaters, useful to quantify vitreous disease severity and the response to therapy. PMID:25613948

Quantitative measurement and real-time tracking of high intensity focused ultrasound using phase-sensitive optical coherence tomography: Feasibility study.

PubMed

Le, Nhan; Song, ShaoZhen; Nabi, Ghulam; Wang, Ruikang; Huang, Zhihong

2016-09-01

Phase-sensitive optical coherence tomography (PhS-OCT) is proposed, as a new high intensity focused ultrasound (HIFU) imaging guidance to detect and track HIFU focus inside 1% agar samples in this work. The experiments studied the effect of varying HIFU power on the induction of shear wave, which can be implemented as a new technique to monitor focused ultrasound surgery (FUS). A miniature HIFU transducer (1.02 MHz, 20 mm aperture diameter, 15 mm radius of curvature) was produced in-house, pressure-field mapped, and calibrated. The transducer was then embedded inside a 1% agar phantom, which was placed under PhS-OCT for observation, under various HIFU power settings (acoustic power, and number of cycles per pulse). Shear wave was induced on the sample surface by HIFU and was captured in full under PhS-OCT. The lowest HIFU acoustic power output for the detection of shear wave was found to be 0.36 W (1.02 MHz, 100 cycles/pulse), or with the number of cycles/pulse as low as 20 (1.02 MHz, 0.98 W acoustic power output). A linear relationship between acoustic power output and the maximum shear wave displacement was found in the first study. The second study explores a non-linear correlation between the (HIFU) numbers of cycles per pulse, and the maximum shear wave displacement. PhS-OCT demonstrates excellent tracking and detection of HIFU-induced shear wave. The results could benefit other imaging techniques in tracking and guiding HIFU focus. Further studies will explore the relationship between the physical transducer characteristics and the HIFU-induced shear wave.

Duplex ultrasound

MedlinePlus

Vascular ultrasound; Peripheral vascular ultrasound ... A duplex ultrasound combines: Traditional ultrasound: This uses sound waves that bounce off blood vessels to create pictures. Doppler ultrasound: This ...

Agreement between calcaneal quantitative ultrasound and osteoporosis self-assessment tool for Asians in identifying individuals at risk of osteoporosis

PubMed Central

Chin, Kok-Yong; Low, Nie Yen; Kamaruddin, Alia Annessa Ain; Dewiputri, Wan Ilma; Soelaiman, Ima-Nirwana

2017-01-01

Background Calcaneal quantitative ultrasound (QUS) is a useful tool in osteoporosis screening. However, QUS device may not be available at all primary health care settings. Osteoporosis self-assessment tool for Asians (OSTA) is a simple algorithm for osteoporosis screening that does not require any sophisticated instruments. This study explored the possibility of replacing QUS with OSTA by determining their agreement in identifying individuals at risk of osteoporosis. Methods A cross-sectional study was conducted to recruit Malaysian men and women aged ≥50 years. Their bone health status was measured using a calcaneal QUS device and OSTA. The association between OSTA and QUS was determined using Spearman’s correlation and their agreement was assessed using Cohen Kappa and receiver-operating curve. Results All QUS indices correlated significantly with OSTA (p<0.05). The agreement between QUS and OSTA was minimal but statistically significant (p<0.05). The performance of OSTA in identifying subjects at risk of osteoporosis according to QUS was poor-to-fair in women (p<0.05), but not statistically significant for men (p>0.05). Changing the cut-off values improved the performance of OSTA in women but not in men. Conclusion The agreement between QUS and OSTA is minimal in categorizing individuals at risk of osteoporosis. Therefore, they cannot be used interchangeably in osteoporosis screening. PMID:29070951

Analysis of ultrasound pulse-echo images for characterization of muscle disease

NASA Astrophysics Data System (ADS)

Leeman, Sidney; Heckmatt, John Z.

1996-04-01

This study aims to extract quantifiable indices characterizing ultrasound propagation and scattering in skeletal muscle, from data acquired using a real-time linear array scanner in a paediatric muscle clinic, in order to establish early diagnosis of Duchenne muscular dystrophy in young children, as well as to chart the progressive severity of the disease. Approximately 40 patients with gait disorders, aged between 1 and 11 years, were scanned with a real-time linear array ultrasound scanner, at 5 MHz. A control group consisted of approximately 50 boys, in the same age range, with no evidence or history of muscle disease. Results show that ultrasound quantitative methods can provide a tight clustering of normal data, and also provide a basis for charting the degree of change in diseased muscle. The most significant (quantitative) parameters derive from the frequency of the attenuation and the muscle echogenicity. The approach provides a discrimination method that is more sensitive than visual assessment of the corresponding image by even an experienced observer. There are also indications that the need for traumatic muscle biopsy may be obviated in some cases.

Comparison of a pocket-size ultrasound device with a premium ultrasound machine: diagnostic value and time required in bedside ultrasound examination.

PubMed

Stock, Konrad Friedrich; Klein, Bettina; Steubl, Dominik; Lersch, Christian; Heemann, Uwe; Wagenpfeil, Stefan; Eyer, Florian; Clevert, Dir-Andre

2015-10-01

Time savings and clinical accuracy of a new miniature ultrasound device was investigated utilizing comparison with conventional high-end ultrasound instruments. Our objective was to determine appropriate usage and limitations of this diagnostic tool in internal medicine. We investigated 28 patients from the internal-medicine department. Patients were examined with the Acuson P10 portable device and a Sonoline Antares instrument in a cross-over design. All investigations were carried out at the bedside; the results were entered on a standardized report form. The time for the ultrasound examination (transfer time, setting up and disassembly, switching on and off, and complete investigation time) was recorded separately. Mean time for overall examination per patient with the portable ultrasound device was shorter (25.0 ± 4.5 min) than with the high-end machine (29.4 ± 4.4 min; p < 0.001). When measuring the size of liver, spleen, and kidneys, the values obtained differed significantly between portable device and the high-end instrument. In our study, we identified 113 pathological ultrasound findings with the high-end ultrasound machine, while 82 pathological findings (73%) were concordantly detected with the portable ultrasound device. The main diagnostic strengths of the portable device were in the detection of ascites (sensitivity 80%), diagnosis of fatty liver, and identification of severe parenchymal liver damage. The clinical utility of portable ultrasound machines is limited. There will be clinical roles for distinct clinical questions such as detection of ascites or pleural effusion when used by experienced examiners. However, sensitivity in detecting multiple pathologies is not comparable to high-end ultrasound machines.

Quantitative analysis of thyroid tumors vascularity: A comparison between 3-D contrast-enhanced ultrasound and 3-D Power Doppler on benign and malignant thyroid nodules.

PubMed

Caresio, Cristina; Caballo, Marco; Deandrea, Maurilio; Garberoglio, Roberto; Mormile, Alberto; Rossetto, Ruth; Limone, Paolo; Molinari, Filippo

2018-05-15

To perform a comparative quantitative analysis of Power Doppler ultrasound (PDUS) and Contrast-Enhancement ultrasound (CEUS) for the quantification of thyroid nodules vascularity patterns, with the goal of identifying biomarkers correlated with the malignancy of the nodule with both imaging techniques. We propose a novel method to reconstruct the vascular architecture from 3-D PDUS and CEUS images of thyroid nodules, and to automatically extract seven quantitative features related to the morphology and distribution of vascular network. Features include three tortuosity metrics, the number of vascular trees and branches, the vascular volume density, and the main spatial vascularity pattern. Feature extraction was performed on 20 thyroid lesions (ten benign and ten malignant), of which we acquired both PDUS and CEUS. MANOVA (multivariate analysis of variance) was used to differentiate benign and malignant lesions based on the most significant features. The analysis of the extracted features showed a significant difference between the benign and malignant nodules for both PDUS and CEUS techniques for all the features. Furthermore, by using a linear classifier on the significant features identified by the MANOVA, benign nodules could be entirely separated from the malignant ones. Our early results confirm the correlation between the morphology and distribution of blood vessels and the malignancy of the lesion, and also show (at least for the dataset used in this study) a considerable similarity in terms of findings of PDUS and CEUS imaging for thyroid nodules diagnosis and classification. © 2018 American Association of Physicists in Medicine.

Attenuation measuring ultrasound shearwave elastography and in vivo application in post-transplant liver patients

NASA Astrophysics Data System (ADS)

Nenadic, Ivan Z.; Qiang, Bo; Urban, Matthew W.; Zhao, Heng; Sanchez, William; Greenleaf, James F.; Chen, Shigao

2017-01-01

Ultrasound and magnetic resonance elastography techniques are used to assess mechanical properties of soft tissues. Tissue stiffness is related to various pathologies such as fibrosis, loss of compliance, and cancer. One way to perform elastography is measuring shear wave velocity of propagating waves in tissue induced by intrinsic motion or an external source of vibration, and relating the shear wave velocity to tissue elasticity. All tissues are inherently viscoelastic and ignoring viscosity biases the velocity-based estimates of elasticity and ignores a potentially important parameter of tissue health. We present attenuation measuring ultrasound shearwave elastography (AMUSE), a technique that independently measures both shear wave velocity and attenuation in tissue and therefore allows characterization of viscoelasticity without using a rheological model. The theoretical basis for AMUSE is first derived and validated in finite element simulations. AMUSE is validated against the traditional methods for assessing shear wave velocity (phase gradient) and attenuation (amplitude decay) in tissue mimicking phantoms and excised tissue. The results agreed within one standard deviation. AMUSE was used to measure shear wave velocity and attenuation in 15 transplanted livers in patients with potential acute rejection, and the results were compared with the biopsy findings in a preliminary study. The comparison showed excellent agreement and suggests that AMUSE can be used to separate transplanted livers with acute rejection from livers with no rejection.

Towards Dynamic Contrast Specific Ultrasound Tomography

NASA Astrophysics Data System (ADS)

Demi, Libertario; van Sloun, Ruud J. G.; Wijkstra, Hessel; Mischi, Massimo

2016-10-01

We report on the first study demonstrating the ability of a recently-developed, contrast-enhanced, ultrasound imaging method, referred to as cumulative phase delay imaging (CPDI), to image and quantify ultrasound contrast agent (UCA) kinetics. Unlike standard ultrasound tomography, which exploits changes in speed of sound and attenuation, CPDI is based on a marker specific to UCAs, thus enabling dynamic contrast-specific ultrasound tomography (DCS-UST). For breast imaging, DCS-UST will lead to a more practical, faster, and less operator-dependent imaging procedure compared to standard echo-contrast, while preserving accurate imaging of contrast kinetics. Moreover, a linear relation between CPD values and ultrasound second-harmonic intensity was measured (coefficient of determination = 0.87). DCS-UST can find clinical applications as a diagnostic method for breast cancer localization, adding important features to multi-parametric ultrasound tomography of the breast.

Towards Dynamic Contrast Specific Ultrasound Tomography.

PubMed

Demi, Libertario; Van Sloun, Ruud J G; Wijkstra, Hessel; Mischi, Massimo

2016-10-05

We report on the first study demonstrating the ability of a recently-developed, contrast-enhanced, ultrasound imaging method, referred to as cumulative phase delay imaging (CPDI), to image and quantify ultrasound contrast agent (UCA) kinetics. Unlike standard ultrasound tomography, which exploits changes in speed of sound and attenuation, CPDI is based on a marker specific to UCAs, thus enabling dynamic contrast-specific ultrasound tomography (DCS-UST). For breast imaging, DCS-UST will lead to a more practical, faster, and less operator-dependent imaging procedure compared to standard echo-contrast, while preserving accurate imaging of contrast kinetics. Moreover, a linear relation between CPD values and ultrasound second-harmonic intensity was measured (coefficient of determination = 0.87). DCS-UST can find clinical applications as a diagnostic method for breast cancer localization, adding important features to multi-parametric ultrasound tomography of the breast.

Towards Dynamic Contrast Specific Ultrasound Tomography

PubMed Central

Demi, Libertario; Van Sloun, Ruud J. G.; Wijkstra, Hessel; Mischi, Massimo

2016-01-01

We report on the first study demonstrating the ability of a recently-developed, contrast-enhanced, ultrasound imaging method, referred to as cumulative phase delay imaging (CPDI), to image and quantify ultrasound contrast agent (UCA) kinetics. Unlike standard ultrasound tomography, which exploits changes in speed of sound and attenuation, CPDI is based on a marker specific to UCAs, thus enabling dynamic contrast-specific ultrasound tomography (DCS-UST). For breast imaging, DCS-UST will lead to a more practical, faster, and less operator-dependent imaging procedure compared to standard echo-contrast, while preserving accurate imaging of contrast kinetics. Moreover, a linear relation between CPD values and ultrasound second-harmonic intensity was measured (coefficient of determination = 0.87). DCS-UST can find clinical applications as a diagnostic method for breast cancer localization, adding important features to multi-parametric ultrasound tomography of the breast. PMID:27703251

Ophthalmic applications of laser-generated ultrasound

NASA Astrophysics Data System (ADS)

Payne, Peter A.; Sadr, Ali; Rosen, Emanuel S.; Dewhurst, Richard J.

2000-06-01

Laser-generated ultrasound has found a number of niche applications in non-destructive testing and evaluation and there is now a growing trend to examine potential applications for materials characterization in medicine. Conventional ultrasound techniques for measuring various important dimensions within the eye are in extensive use. However, one problem remains outstanding, which is that the dimensions of the cornea, anterior chamber and lens can be measured using a high frequency, high resolution transducer, but the dimensions of the overall eyeball (i.e., cornea to retina) have to be measured with a lower frequency transducer in order to achieve the necessary penetration. We have conducted a number of in vitro studies using bovine eyes to determine whether the use of laser induced ultrasound would be able to overcome the aforementioned problem. The results of these measurements will be presented, together with a discussion of the many difficulties that remain to be overcome. In addition, our studies involve the potential use of laser ultrasound to quantify the degree of cataract formation, both primary and secondary. This paper will also consider the work accomplished to data in this area.

[Size of testes and epididymes in boys up to 17 years of life assessed by ultrasound method and method of external linear measurements].

PubMed

Osemlak, Paweł

2011-01-01

1. Determination of the size of testes and epididymes on the right and left side, in healthy boys in various age groups with use of non-invasive ultrasound examination method and the method of external linear measurements. 2. Determination of age, when intensive growth of testicular and epididymal size starts. 3. Determination whether there are statistically significant differences between the size of the right and the left testis, as well as between the right and left epididymis. 4. Evaluation of the ultrasound method and method of external linear measurements in their use for scientific investigations. 309 boys, aged from 1 day to 17 years of life, treated in the Clinical Department of Paediatric Surgery and Traumatology of the Medical University in Lublin from 2009 to 2010 due to diseases needed to be treated surgically, but not the scrotum, were examined in this study. No pathologies influencing the development of genital organs were found in these boys. Dimension of the testes was studied with ultrasound method and with method of external linear measurements. Dimension of epididymes was only examined with ultrasound method. In every age group the author calculated mean arithmetical values for: testiscular length, thickness, width and volume, as well as epididymal depth and basis. With consideration of standard deviation (X+/-1 SD) it was possible to define the range of dimension of healthy testes and epididymes and their change with age. Final dimensions of the right and left testis as well as of the right and left epididymis were compared. Dimensions of the testis on the same side of body acquired with the ultrasound method and acquired with the method of external linear measurements were compared. Statistical work-up with Wilcoxon test for two dependent groups was implemented. Ultrasound evaluation pointed to intensive 2.5-times increase in testicular length and width, and 2-times increase in testicular thickness in boys aged 10 to 17 years. Mean volume of

Application of a Sub-set of Skinfold Sites for Ultrasound Measurement of Subcutaneous Adiposity and Percentage Body Fat Estimation in Athletes.

PubMed

O'Neill, D C; Cronin, O; O'Neill, S B; Woods, T; Keohane, D M; Molloy, M G; Falvey, E C

2016-05-01

Body composition assessment is an integral feature of elite sport as optimization facilitates successful performance. This study aims to refine the use of B-mode ultrasound in the assessment of athlete body composition by determining suitable sites for measurement. 67 elite athletes recruited from the Human Performance Laboratory, University College Cork, Ireland, underwent dual measurement of body composition. Subcutaneous adipose tissue thickness at 7 anatomical sites were measured using ultrasound and compared to percentage body fat values determined using Dual-Energy X-ray Absorptiometry. Multiple linear regressions were performed and an equation to predict percentage body fat was derived. The present study found subcutaneous adipose tissue depths at the triceps, biceps, anterior thigh and supraspinale sites correlated significantly with percentage body fat by X-ray absorptiometry (all p<0.05). Summation of the depths at these locations correlated strongly with percentage body fat by Dual-Energy X-ray Absorptiometry (R²=0.879). The triceps, biceps, anterior thigh and supraspinale sites are suitable anatomical landmarks for the estimation of %BF using B-mode ultrasound. Use of B-mode ultrasound in the assessment of athlete body composition confers many benefits including lack of ionising radiation and its potential to be used as a portable field tool. © Georg Thieme Verlag KG Stuttgart · New York.

Quantitative measurement of marginal disintegration of ceramic inlays.

PubMed

Hayashi, Mikako; Tsubakimoto, Yuko; Takeshige, Fumio; Ebisu, Shigeyuki

2004-01-01

The objectives of this study include establishing a method for quantitative measurement of marginal change in ceramic inlays and clarifying their marginal disintegration in vivo. An accurate CCD optical laser scanner system was used for morphological measurement of the marginal change of ceramic inlays. The accuracy of the CCD measurement was assessed by comparing it with microscopic measurement. Replicas of 15 premolars restored with Class II ceramic inlays at the time of placement and eight years after restoration were used for morphological measurement by means of the CCD laser scanner system. Occlusal surfaces of the restored teeth were scanned and cross-sections of marginal areas were computed with software. Marginal change was defined as the area enclosed by two profiles obtained by superimposing two cross-sections of the same location at two different times and expressing the maximum depth and mean area of the area enclosed. The accuracy of this method of measurement was 4.3 +/- 3.2 microm in distance and 2.0 +/- 0.6% in area. Quantitative marginal changes for the eight-year period were 10 x 10 microm in depth and 50 x 10(3) microm2 in area at the functional cusp area and 7 x 10 microm in depth and 28 x 10(3) microm2 in area at the non-functional cusp area. Marginal disintegration at the functional cusp area was significantly greater than at the non-functional cusp area (Wilcoxon signed-ranks test, p < 0.05). This study constitutes a quantitative measurement of in vivo deterioration in marginal adaptation of ceramic inlays and indicates that occlusal force may accelerate marginal disintegration.

The relationship between experimental geometry, heat rate, and ultrasound wave speed measurement while observing phase changes in highly attenuative materials

NASA Astrophysics Data System (ADS)

Moore, David G.; Stair, Sarah L.; Jack, David A.

2018-04-01

Ultrasound techniques are capable of monitoring changes in the time-of-flight as a material is exposed to different thermal environments. The focus of the present study is to identify the phase of a material via ultrasound compression wave measurements in a through transmission experimental setup as the material is heated from a solid to a liquid and then allowed to re-solidify. The present work seeks to expand upon the authors' previous research, which proved this through transmission phase monitoring technique was possible, by considering different experimental geometries. The relationship between geometry, the measured speed of sound, and the temperature profile is presented. The use of different volumes helps in establishing a baseline understanding of which aspects of the experiment are geometry dependent and which are independent. The present study also investigates the relationship between the heating rate observed in the experiment and the measured speed of sound. The trends identified between the experimental geometry, heat rate and ultrasound wave speed measurement assist in providing a baseline understanding of the applicability of this technique to various industries, including the polymer industry and the oil industry.

The Relationship Between Experimental Geometry Heat Rate and Ultrasound Wave Speed Measurement While Observing Phase Changes in Highly Attenuative Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, David G.; Stair, Sarah Louise; Jack, David A.

Ultrasound techniques are capable of monitoring changes in the time-of-flight as a material is exposed to different thermal environments. The focus of the present study is to identify the phase of a material via ultrasound compression wave measurements in a through transmission experimental setup as the material is heated from a solid to a liquid and then allowed to re-solidify. The present work seeks to expand upon the authors’ previous research, which proved this through transmission phase monitoring technique was possible, by considering different experimental geometries. The relationship between geometry, the measured speed of sound, and the temperature profile ismore » presented. The use of different volumes helps in establishing a baseline understanding of which aspects of the experiment are geometry dependent and which are independent. The present study also investigates the relationship between the heating rate observed in the experiment and the measured speed of sound. Lastly, the trends identified between the experimental geometry, heat rate and ultrasound wave speed measurement assist in providing a baseline understanding of the applicability of this technique to various industries, including the polymer industry and the oil industry.« less

The Relationship Between Experimental Geometry Heat Rate and Ultrasound Wave Speed Measurement While Observing Phase Changes in Highly Attenuative Materials

DOE PAGES

Moore, David G.; Stair, Sarah Louise; Jack, David A.

2018-04-01

Ultrasound techniques are capable of monitoring changes in the time-of-flight as a material is exposed to different thermal environments. The focus of the present study is to identify the phase of a material via ultrasound compression wave measurements in a through transmission experimental setup as the material is heated from a solid to a liquid and then allowed to re-solidify. The present work seeks to expand upon the authors’ previous research, which proved this through transmission phase monitoring technique was possible, by considering different experimental geometries. The relationship between geometry, the measured speed of sound, and the temperature profile ismore » presented. The use of different volumes helps in establishing a baseline understanding of which aspects of the experiment are geometry dependent and which are independent. The present study also investigates the relationship between the heating rate observed in the experiment and the measured speed of sound. Lastly, the trends identified between the experimental geometry, heat rate and ultrasound wave speed measurement assist in providing a baseline understanding of the applicability of this technique to various industries, including the polymer industry and the oil industry.« less

Molecular Ultrasound Imaging for the Detection of Neural Inflammation

NASA Astrophysics Data System (ADS)

Volz, Kevin R.

performed while targeting three early inflammatory markers (P-selectin, VCAM-1, ICAM-1). Imaging protocols and outcome measures of previous TCEUS investigations of inflammation were replicated to aid in comparisons of outcomes. Signal intensity data was used to generate time intensity curves for qualitative and quantitative analysis of contrast agent temporal behavior. A proof of principle study established preclinical evidence to support the ability of TCEUS to detect acute neural inflammation. Substantial increases in signal intensities were observed while targeting inflammatory markers compared to controls. Further investigations consisted of examining molecular ultrasound sensitivity, and were accomplished by examining targeted contrast agent dosing parameters, and the ability of TCEUS to longitudinally evaluate neural inflammation. Qualitative analysis of TCEUS imaging performed with both administered doses revealed marked increases in signal intensities during acute inflammation, where inflammatory marker expression was presumably at its highest. This was in comparison to measures obtained in the absence of, and during, chronic inflammation. This research contributes much needed empirical evidence to the molecular ultrasound body of literature, and represents the first steps towards advancing this TCEUS application to clinical practice. Future studies are necessary to further these findings and effectively build upon this evidence. Increasing evidence of TCEUS use for the detection of neural inflammation will aid in its eventual clinical translation, where it will likely have a positive impact on patient care.

Standardized 2D ultrasound versus 3D/4D ultrasound and image fusion for measurement of aortic aneurysm diameter in follow-up after EVAR.

PubMed

Pfister, Karin; Schierling, Wilma; Jung, Ernst Michael; Apfelbeck, Hanna; Hennersperger, Christoph; Kasprzak, Piotr M

2016-01-01

To compare standardised 2D ultrasound (US) to the novel ultrasonographic imaging techniques 3D/4D US and image fusion (combined real-time display of B mode and CT scan) for routine measurement of aortic diameter in follow-up after endovascular aortic aneurysm repair (EVAR). 300 measurements were performed on 20 patients after EVAR by one experienced sonographer (3rd degree of the German society of ultrasound (DEGUM)) with a high-end ultrasound machine and a convex probe (1-5 MHz). An internally standardized scanning protocol of the aortic aneurysm diameter in B mode used a so called leading-edge method. In summary, five different US methods (2D, 3D free-hand, magnetic field tracked 3D - Curefab™, 4D volume sweep, image fusion), each including contrast-enhanced ultrasound (CEUS), were used for measurement of the maximum aortic aneurysm diameter. Standardized 2D sonography was the defined reference standard for statistical analysis. CEUS was used for endoleak detection. Technical success was 100%. In augmented transverse imaging the mean aortic anteroposterior (AP) diameter was 4.0±1.3 cm for 2D US, 4.0±1.2 cm for 3D Curefab™, and 3.9±1.3 cm for 4D US and 4.0±1.2 for image fusion. The mean differences were below 1 mm (0.2-0.9 mm). Concerning estimation of aneurysm growth, agreement was found between 2D, 3D and 4D US in 19 of the 20 patients (95%). Definitive decision could always be made by image fusion. CEUS was combined with all methods and detected two out of the 20 patients (10%) with an endoleak type II. In one case, endoleak feeding arteries remained unclear with 2D CEUS but could be clearly localized by 3D CEUS and image fusion. Standardized 2D US allows adequate routine follow-up of maximum aortic aneurysm diameter after EVAR. Image Fusion enables a definitive statement about aneurysm growth without the need for new CT imaging by combining the postoperative CT scan with real-time B mode in a dual image display. 3D/4D CEUS and image fusion

Plantar fasciitis (fasciosis) treatment outcome study: plantar fascia thickness measured by ultrasound and correlated with patient self-reported improvement.

PubMed

Fabrikant, Jerry M; Park, Tae Soon

2011-06-01

Ultrasound, well recognized as an effective diagnostic tool, reveals a thickening of the plantar fascia in patients with plantar fasciitis/fasciosis disease. The authors hypothesized that ultrasound would also reveal a decrease in the plantar fascia thickness for patients undergoing treatment for the disease, a hypothesis that, heretofore, had been only tested on a limited number of subjects. They conducted a more statistically significant study that found that clinical treatment with injection and biomechanical correction does indeed diminish plantar fascia thickness as shown on ultrasound. The study also revealed that patients experience the most heightened plantar fascia tenderness toward the end of the day, and improvement in their symptomatic complaints were associated with a reduction in plantar fascia thickness. As a result, the authors conclude that office-based ultrasound can help diagnose and confirm plantar fasciitis/fasciosis through the measurement of the plantar fascia thickness. Because of the advantages of ultrasound--that it is non-invasive with greater patient acceptance, cost effective and radiation-free--the imaging tool should be considered and implemented early in the diagnosis and treatment of plantar fasciitis/fasciosis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Non-Invasive Measurement of Pulsatile Intracranial Pressures Using Ultrasound

NASA Technical Reports Server (NTRS)

Ueno, Toshiaki; Ballard, Richard E.; Shuer, Lawrence M.; Cantrell, John H.; Cantrell, John H.; Hargens, Alan R.

1997-01-01

Early detection of elevated intracranial pressure (ICP) will aid clinical decision-making for head trauma, brain tumor and other cerebrovascular diseases. Conventional methods, however, require surgical procedures which take time and are accompanied by increased risk of infection. Accordingly we have developed and refined a new ultrasound device to measure skull movements which are known to occur in conjunction with altered ICP. The principle of this device is based upon pulse phase locked loop (PPLL), which enables us to detect changes in distance on the order of microns between an ultrasound transducer on one side of the skull and the opposite inner surface of the cranium. The present study was designed to verify this measurement technique in cadavera. Transcranial distance was increased in steps of 10 mmHg from zero to 50 mmHg by saline infusion into the lateral ventricle of two cadavera. In separate experiments, pulsations of ICP with the amplitudes of zero to 2 mmHg were generated by rhythmic injections of saline using a syringe. When the ICP was stepwise increased from zero to 50 mmHg, transcranial distance increased in proportion with the ICP increase (y=12 x - 76, r=0.938), where y is changes in transcranial distance in microns and x is ICP in mmHg. In the data recorded while ICP pulsations were generated, fast Fourier transform analysis demonstrated that cranial pulsations were clearly associated with ICP pulsations. The results indicate that changes in transcranial distance is linearly correlated with those in ICP, and also that the PPLL device has sufficient sensitivity to detect transcranial pulsations which occur in association with the cardiac cycle. By analyzing the magnitude of cranial pulsations, we may be able to estimate the pressure-volume index in the cranium. As a result, estimates of intracranial compliance may be possible by using the PPLL device. Further studies are necessary in normal subjects and patients.

A Novel Method for Measuring Anterior Segment Area of the Eye on Ultrasound Biomicroscopic Images Using Photoshop

PubMed Central

Wu, Ziqiang; Lin, Jialiu; Huang, Jingjing

2015-01-01

Purpose To describe a novel method for quantitative measurement of area parameters in ocular anterior segment ultrasound biomicroscopy (UBM) images using Photoshop software and to assess its intraobserver and interobserver reproducibility. Methods Twenty healthy volunteers with wide angles and twenty patients with narrow or closed angles were consecutively recruited. UBM images were obtained and analyzed using Photoshop software by two physicians with different-level training on two occasions. Borders of anterior segment structures including cornea, iris, lens, and zonules in the UBM image were semi-automatically defined by the Magnetic Lasso Tool in the Photoshop software according to the pixel contrast and modified by the observers. Anterior chamber area (ACA), posterior chamber area (PCA), iris cross-section area (ICA) and angle recess area (ARA) were drawn and measured. The intraobserver and interobserver reproducibilities of the anterior segment area parameters and scleral spur location were assessed by limits of agreement, coefficient of variation (CV), and intraclass correlation coefficient (ICC). Results All of the parameters were successfully measured by Photoshop. The intraobserver and interobserver reproducibilities of ACA, PCA, and ICA were good, with no more than 5% CV and more than 0.95 ICC, while the CVs of ARA were within 20%. The intraobserver and interobserver reproducibilities for defining the spur location were more than 0.97 ICCs. Although the operating times for both observers were less than 3 minutes per image, there was significant difference in the measuring time between two observers with different levels of training (p<0.001). Conclusion Measurements of ocular anterior segment areas on UBM images by Photoshop showed good intraobserver and interobserver reproducibilties. The methodology was easy to adopt and effective in measuring. PMID:25803857

Diffuse optical tomography using semiautomated coregistered ultrasound measurements

NASA Astrophysics Data System (ADS)

Mostafa, Atahar; Vavadi, Hamed; Uddin, K. M. Shihab; Zhu, Quing

2017-12-01

Diffuse optical tomography (DOT) has demonstrated huge potential in breast cancer diagnosis and treatment monitoring. DOT image reconstruction guided by ultrasound (US) improves the diffused light localization and lesion reconstruction accuracy. However, DOT reconstruction depends on tumor geometry provided by coregistered US. Experienced operators can manually measure these lesion parameters; however, training and measurement time are needed. The wide clinical use of this technique depends on its robustness and faster imaging reconstruction capability. This article introduces a semiautomated procedure that automatically extracts lesion information from US images and incorporates it into the optical reconstruction. An adaptive threshold-based image segmentation is used to obtain tumor boundaries. For some US images, posterior shadow can extend to the chest wall and make the detection of deeper lesion boundary difficult. This problem can be solved using a Hough transform. The proposed procedure was validated from data of 20 patients. Optical reconstruction results using the proposed procedure were compared with those reconstructed using extracted tumor information from an experienced user. Mean optical absorption obtained from manual measurement was 0.21±0.06 cm-1 for malignant and 0.12±0.06 cm-1 for benign cases, whereas for the proposed method it was 0.24±0.08 cm-1 and 0.12±0.05 cm-1, respectively.

Survey of ultrasound practice amongst podiatrists in the UK.

PubMed

Siddle, Heidi J; Patience, Aimie; Coughtrey, James; Mooney, Jean; Fox, Martin; Cherry, Lindsey

2018-01-01

Ultrasound in podiatry practice encompasses musculoskeletal ultrasound imaging, vascular hand-held Doppler ultrasound and therapeutic ultrasound. Sonography practice is not regulated by the Health and Care Professions Council (HCPC), with no requirement to hold a formal qualification. The College of Podiatry does not currently define ultrasound training and competencies.This study aimed to determine the current use of ultrasound, training received and mentorship received and/or provided by podiatrists using ultrasound. A quantitative study utilising a cross-sectional, on-line, single-event survey was undertaken within the UK. Completed surveys were received from 284 podiatrists; 173 (70%) use ultrasound as part of their general practice, 139 (49%) for musculoskeletal problems, 131 (46%) for vascular assessment and 39 (14%) to support their surgical practice. Almost a quarter ( n  = 62) worked for more than one organisation; 202 (71%) were employed by the NHS and/or private sector ( n  = 118, 41%).Nearly all (93%) respondents report using a hand-held vascular Doppler in their daily practice; 216 (82%) to support decisions regarding treatment options, 102 (39%) to provide diagnostic reports for other health professionals, and 34 (13%) to guide nerve blocks.Ultrasound imaging was used by 104 (37%) respondents primarily to aid clinical decision making ( n  = 81) and guide interventions (steroid injections n  = 67; nerve blocks n  = 39). Ninety-three percent stated they use ultrasound imaging to treat their own patients, while others scan at the request of other podiatrists ( n  = 28) or health professionals ( n  = 18). Few use ultrasound imaging for research ( n  = 7) or education ( n  = 2).Only 32 (11%) respondents ( n  = 20 private sector) use therapeutic ultrasound to treat patients presenting with musculoskeletal complaints, namely tendon pathologies.Few respondents (18%) had completed formal post-graduate CASE (Consortium

Can Ultrasound Accurately Assess Ischiofemoral Space Dimensions? A Validation Study.

PubMed

Finnoff, Jonathan T; Johnson, Adam C; Hollman, John H

2017-04-01

Ischiofemoral impingement is a potential cause of hip and buttock pain. It is evaluated commonly with magnetic resonance imaging (MRI). To our knowledge, no study previously has evaluated the ability of ultrasound to measure the ischiofemoral space (IFS) dimensions reliably. To determine whether ultrasound could accurately measure the IFS dimensions when compared with the gold standard imaging modality of MRI. A methods comparison study. Sports medicine center within a tertiary-care institution. A total of 5 male and 5 female asymptomatic adult subjects (age mean = 29.2 years, range = 23-35 years; body mass index mean = 23.5, range = 19.5-26.6) were recruited to participate in the study. Subjects were secured in a prone position on a MRI table with their hips in a neutral position. Their IFS dimensions were then acquired in a randomized order using diagnostic ultrasound and MRI. The main outcome measurements were the IFS dimensions acquired with ultrasound and MRI. The mean IFS dimensions measured with ultrasound was 29.5 mm (standard deviation [SD] 4.99 mm, standard error mean 1.12 mm), whereas those obtained with MRI were 28.25 mm (SD 5.91 mm, standard error mean 1.32 mm). The mean difference between the ultrasound and MRI measurements was 1.25 mm, which was not statistically significant (SD 3.71 mm, standard error mean 3.71 mm, 95% confidence interval -0.49 mm to 2.98 mm, t 19 = 1.506, P = .15). The Bland-Altman analysis indicated that the 95% limits of agreement between the 2 measurement was -6.0 to 8.5 mm, indicating that there was no systematic bias between the ultrasound and MRI measurements. Our findings suggest that the IFS measurements obtained with ultrasound are very similar to those obtained with MRI. Therefore, when evaluating individuals with suspected ischiofemoral impingement, one could consider using ultrasound to measure their IFS dimensions. III. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier

Semiautomated thyroid volumetry using 3D CT: prospective comparison with measurements obtained using 2D ultrasound, 2D CT, and water displacement method of specimen.

PubMed

Lee, Sun Jin; Chong, Semin; Kang, Kyung Ho; Hur, Joonho; Hong, Byung-Woo; Kim, Hyun Jung; Kim, Soo Jin

2014-11-01

The objective of our study was to measure thyroid volumes using semiautomated 3D CT and to compare the 3D CT volumes with volumes measured using 2D ultrasound, 2D CT, and the water displacement method. In 47 patients, 2D ultrasound volumes and 2D CT volumes of the thyroid gland were estimated using the ellipsoid volume formula, and 3D CT volumes were calculated using semiautomated reconstructive techniques. All volume data were compared with thyroid specimen volumes obtained using the water displacement method and were statistically analyzed using the one-way ANOVA, the Pearson correlation coefficient (R), linear regression, and the concordance correlation coefficient (CCC). The processing time of semiautomated 3D CT thyroid volumetry was measured. The paired mean differences ± SD between the three imaging-determined volumes and the specimen volumes were 0.8 ± 3.1 mL for 2D ultrasound, 4.0 ± 4.7 mL for 2D CT, and 0.2 ± 2.5 mL for 3D CT. A significant difference in the mean thyroid volume was found between 2D CT and specimen volumes (p = 0.016) compared with the other pairs (p = 0.937 for 2D ultrasound mean volume vs specimen mean volume, and p = 0.999 for 3D CT mean volume vs specimen mean volume). Between specimen volume and 2D ultrasound volume, specimen volume and 2D CT volume, and specimen volume and 3D CT volume, R values were 0.885, 0.724, and 0.929, respectively, and CCC values were 0.876, 0.598, and 0.925, respectively. The mean processing time of semiautomated 3D CT thyroid volumetry was 7.0 minutes. Thyroid volumes measured using 2D ultrasound or semiautomated 3D CT are substantially close to thyroid specimen volumes measured using the water displacement method. Semiautomated 3D CT thyroid volumetry can provide a more reliable measure of thyroid volume than 2D ultrasound.

Ultrasound measurement apparatus for liquids characterization

NASA Astrophysics Data System (ADS)

Vieira, R. C.; Costa-Felix, R. P. B.

2018-03-01

The present paper discloses the validation of an experimental ultrasound apparatus and method for liquids characterization. The research aims to stablish a simple, reliable, accurate and portable way to identify contaminants in hydrocarbon substances, such as adulteration in gasoline. The results depicted so far demonstrated a general uncertainty of speed of sound assessment less than 10 m s-1, and distance accuracy of less than 1%. Those figures are good enough for an in-site device to evaluate possible contamination of fuels or other liquids.

The accuracy of ultrasound for measurement of mobile- bearing motion.

PubMed

Aigner, Christian; Radl, Roman; Pechmann, Michael; Rehak, Peter; Stacher, Rudolf; Windhager, Reinhard

2004-04-01

After anterior cruciate ligament-sacrificing total knee replacement, mobile bearings sometimes have paradoxic movement but the implications of such movement on function, wear, and implant survival are not known. To study this potential problem accurate, reliable, and widely available inexpensive tools for in vivo mobile-bearing motion analyses are needed. We developed a method using an 8-MHz ultrasound to analyze mobile-bearing motion and ascertained accuracy, precision, and reliability compared with plain and standard digital radiographs. The anterior rim of the mobile bearing was the target for all methods. The radiographs were taken in a horizontal plane at neutral rotation and incremental external and internal rotations. Five investigators examined four positions of the mobile bearing with all three methods. The accuracy and precision were: ultrasound, 0.7 mm and 0.2 mm; digital radiograph, 0.4 mm and 0.2 mm; and plain radiographs, 0.7 mm and 0.3 mm. The interrater and intrarater reliability ranged between 0.3 to 0.4 mm and 0.1 to 0.2 mm, respectively. The difference between the methods was not significant for neutral rotation but ultrasound was significantly more accurate than any one degree of rotation or higher. Ultrasound of 8 MHz provides an accuracy and reliability that is suitable for evaluation of in vivo meniscal bearing motion. Whether this method or others are sufficiently accurate to detect motion leading to abnormal wear is not known.

A novel technique for fetal heart rate estimation from Doppler ultrasound signal

PubMed Central

2011-01-01

Background The currently used fetal monitoring instrumentation that is based on Doppler ultrasound technique provides the fetal heart rate (FHR) signal with limited accuracy. It is particularly noticeable as significant decrease of clinically important feature - the variability of FHR signal. The aim of our work was to develop a novel efficient technique for processing of the ultrasound signal, which could estimate the cardiac cycle duration with accuracy comparable to a direct electrocardiography. Methods We have proposed a new technique which provides the true beat-to-beat values of the FHR signal through multiple measurement of a given cardiac cycle in the ultrasound signal. The method consists in three steps: the dynamic adjustment of autocorrelation window, the adaptive autocorrelation peak detection and determination of beat-to-beat intervals. The estimated fetal heart rate values and calculated indices describing variability of FHR, were compared to the reference data obtained from the direct fetal electrocardiogram, as well as to another method for FHR estimation. Results The results revealed that our method increases the accuracy in comparison to currently used fetal monitoring instrumentation, and thus enables to calculate reliable parameters describing the variability of FHR. Relating these results to the other method for FHR estimation we showed that in our approach a much lower number of measured cardiac cycles was rejected as being invalid. Conclusions The proposed method for fetal heart rate determination on a beat-to-beat basis offers a high accuracy of the heart interval measurement enabling reliable quantitative assessment of the FHR variability, at the same time reducing the number of invalid cardiac cycle measurements. PMID:21999764

Quantitative force measurements in liquid using frequency modulation atomic force microscopy

NASA Astrophysics Data System (ADS)

Uchihashi, Takayuki; Higgins, Michael J.; Yasuda, Satoshi; Jarvis, Suzanne P.; Akita, Seiji; Nakayama, Yoshikazu; Sader, John E.

2004-10-01

The measurement of short-range forces with the atomic force microscope (AFM) typically requires implementation of dynamic techniques to maintain sensitivity and stability. While frequency modulation atomic force microscopy (FM-AFM) is used widely for high-resolution imaging and quantitative force measurements in vacuum, quantitative force measurements using FM-AFM in liquids have proven elusive. Here we demonstrate that the formalism derived for operation in vacuum can also be used in liquids, provided certain modifications are implemented. To facilitate comparison with previous measurements taken using surface forces apparatus, we choose a model system (octamethylcyclotetrasiloxane) that is known to exhibit short-ranged structural ordering when confined between two surfaces. Force measurements obtained are found to be in excellent agreement with previously reported results. This study therefore establishes FM-AFM as a powerful tool for the quantitative measurement of forces in liquid.

WE-EF-210-06: Ultrasound 2D Strain Measurement of Radiation-Induced Toxicity: Phantom and Ex Vivo Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, T; Torres, M; Rossi, P

Purpose: Radiation-induced fibrosis is a common long-term complication affecting many patients following cancer radiotherapy. Standard clinical assessment of subcutaneous fibrosis is subjective and often limited to visual inspection and palpation. Ultrasound strain imaging describes the compressibility (elasticity) of biological tissues. This study’s purpose is to develop a quantitative ultrasound strain imaging that can consistently and accurately characterize radiation-induce fibrosis. Methods: In this study, we propose a 2D strain imaging method based on deformable image registration. A combined affine and B-spline transformation model is used to calculate the displacement of tissue between pre-stress and post-stress B-mode image sequences. The 2D displacementmore » is estimated through a hybrid image similarity measure metric, which is a combination of the normalized mutual information (NMI) and normalized sum-of-squared-differences (NSSD). And 2D strain is obtained from the gradient of the local displacement. We conducted phantom experiments under various compressions and compared the performance of our proposed method with the standard cross-correlation (CC)- based method using the signal-to-noise (SNR) and contrast-to-noise (CNS) ratios. In addition, we conducted ex-vivo beef muscle experiment to further validate the proposed method. Results: For phantom study, the SNR and CNS values of the proposed method were significantly higher than those calculated from the CC-based method under different strains. The SNR and CNR increased by a factor of 1.9 and 2.7 comparing to the CC-based method. For the ex-vivo experiment, the CC-based method failed to work due to large deformation (6.7%), while our proposed method could accurately detect the stiffness change. Conclusion: We have developed a 2D strain imaging technique based on the deformable image registration, validated its accuracy and feasibility with phantom and ex-vivo data. This 2D ultrasound strain

Temperature Dependence of Parametric Phenomenon in Airborne Ultrasound for Temperature Measurement

NASA Astrophysics Data System (ADS)

Kon, Akihiko; Wakatsuki, Naoto; Mizutani, Koichi

2008-08-01

The temperature dependence of parametric phenomenon in air was experimentally studied. It was confirmed from experimental data that the amplitude of upper sideband sound with a frequency of 36.175 kHz, which is caused by parametric phenomenon between high-power ultrasound with a frequency of 20.175 kHz and another normal sound with a frequency of 16.0 kHz, is proportional to -0.88×10-4×(T+273.15). This temperature dependence of the amplitude of upper sideband sound caused by the parametric phenomenon suggests a simple and effective method of temperature measurement.

Inter- and intratester reliability values of ultrasound imaging measurements of diaphragm movement in the thoracic and thoracolumbar curves in adolescent idiopathic scoliosis.

PubMed

Noh, Dong Koog; Koh, Jae-Hyun; You, Joshua Sung-H

2016-01-01

The purpose of this study was to determine intertester and intratester reliability of ultrasound measurements of bilateral diaphragm excursions in the thoracic and thoracolumbar spinal curves of 31 females with adolescent idiopathic scoliosis (AIS) (mean age = 14.1 ± 1.8 years). Subjects were tested during tidal breathing using real-time ultrasound imaging with a 3.5 MHz curvilinear transducer. There were no significant differences in intratester and intertester reliability values in bilateral diaphragmatic excursions measured at the thoracolumbar spinal curve, whereas significant differences were observed in measurements taken at the thoracic spinal curve (p < 0.05). Overall, the intertester and intratester reliabilities of the thoracic and thoracolumbar curves in AIS ranged from 0.764 to 0.998. These findings suggest that ultrasound imaging is highly reliable between and within testers and is useful to precisely discriminate pathological diaphragm movement in idiopathic thoracic scoliosis and idiopathic thoracolumbar scoliosis.

Measuring tongue shapes and positions with ultrasound imaging: a validation experiment using an articulatory model.

PubMed

Ménard, Lucie; Aubin, Jérôme; Thibeault, Mélanie; Richard, Gabrielle

2012-01-01

The goal of this paper is to assess the validity of various metrics developed to characterize tongue shapes and positions collected through ultrasound imaging in experimental setups where the probe is not constrained relative to the subject's head. Midsagittal contours were generated using an articulatory-acoustic model of the vocal tract. Sections of the tongue were extracted to simulate ultrasound imaging. Various transformations were applied to the tongue contours in order to simulate ultrasound probe displacements: vertical displacement, horizontal displacement, and rotation. The proposed data analysis method reshapes tongue contours into triangles and then extracts measures of angles, x and y coordinates of the highest point of the tongue, curvature degree, and curvature position. Parameters related to the absolute tongue position (tongue height and front/back position) are more sensitive to horizontal and vertical displacements of the probe, whereas parameters related to tongue curvature are less sensitive to such displacements. Because of their robustness to probe displacements, parameters related to tongue shape (especially curvature) are particularly well suited to cases where the transducer is not constrained relative to the head (studies with clinical populations or children). Copyright © 2011 S. Karger AG, Basel.