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Pulmonary hypoplasia is associated with severe respiratory distress immediately after birth and frequently leads to neonatal death. In this study, we compared the fetal lung echo texture in pregnancies at high and low risk for pulmonary hypoplasia. Ultrasonic tissue heterogeneity was determined by a dynamic range calculation. This quantification uses a dithering technique based on the Floyd-Steinberg algorithm, in which the pixels are transformed into a binary map. Pregnancies at high risk for pulmonary hypoplasia showed decreased fetal lung heterogeneity on ultrasound imaging. This image-processing technique may allow improved risk stratification, patient counseling, and treatment approaches for pulmonary hypoplasia.

Fetal ultrasound has been employed for years to help evaluate fetal growth and development and to monitor pregnancy. Furthermore, fetal lung maturity has been assessed pre-natally by examination of the amniotic fluid, usually obtained by transabdominal amniocentesis, for lecithin, lecithin/sphingomyelin ratio, or “P” factor (fluorescent polarization measurement for lipids.) Quantitative ultrasound texture analysis of fetal lung has been proposed in previous studies as a promising noninvasive method to predict fetal lung maturity, fetal lung hypoplasia, and neonatal respiratory morbidity. This technique utilizes standard fetal lung images, which are easily obtained by sonographers during routine ultrasound examinations. Additional information then can be extracted from these images by applying quantitative processing methods that characterize the tissue. This presentation discusses how to differentiate preterm (

The kidneys are thought to contribute to the pathogenesis of primary hypertension, but hypertension is also known to cause target organ damage in the kidney. Noninvasive methods to capture possible changes in the kidney related to hypertension are limited. A new program that has been used to quantify the heterogeneity and percent echogenicity in renal ultrasound images was implemented to assess patients with hypertension. Children and adolescents21 years with primary hypertension diagnosed by ambulatory blood pressure monitoring were compared with normotensive age- and sex-matched controls. Renal ultrasound images were evaluated by a technique that measured pixels of gray-scale images and transformed them into a binary map, which was converted to a heterogeneity index (HI) and percent echogenicity score. This study included 99 children with hypertension and 99 control subjects. Body mass index (BMI) was greater in the hypertension group. Average HI for hypertension was significantly higher than in controls (1.37 ± 0.19 vs. 1.2 ± 0.23, P = .001), while echogenicity scores were not different (26.6 ± 8.9 vs. 25.9 ± 10, P = .8). In regression analysis adjusting for BMI z-score and race, hypertension was associated with greater HI compared with controls (β = 0.11, 95% confidence interval 0.03-0.18, P = .005). In a model adjusted for age, sex, and BMI z-score in the hypertension group only, no ambulatory blood pressure monitoring measures were associated with HI or echogenicity scores (P .05).HI was significantly greater in the hypertension group compared with normotensive controls. HI may be a novel method to detect changes in the kidney related to hypertension.

Background In a normal pregnancy, cervical collagen fibers remain organized in predictable patterns throughout most of the gestation. Cervical remodeling reflects a rearrangement of collagen fibers in which they become increasingly disordered and contribute to the pathogenesis of spontaneous preterm birth. Quantitative ultrasound analysis of cervical tissue echotexture may have the capacity to identify microstructural changes before the onset of cervical shortening. Objective The primary objective of this study was to examine the utility of a novel quantitative sonographic marker, the cervical heterogeneity index (HI), which reflects the relative organization of cervical collagen fibers. Also, we aimed to determine an optimal HI cut-point to predict spontaneous preterm birth. Study Design This retrospective cohort study employed a novel image-processing technique on transvaginal ultrasound images of the cervix in gestations between 14 and 28 completed weeks. The transvaginal sonography images were analyzed in MATLAB (MathWorks, Natick, MA) using a custom image-processing technique that assessed the relative heterogeneity of the cervical tissue. Results A total of 151 subjects were included in the study. The mean HI in subjects who delivered preterm and at term was 8.28 ± 3.73 and 12.35 ± 5.80, respectively (p Conclusion Quantitative ultrasound measurement of the cervical HI is a promising, noninvasive tool for early prediction of spontaneous preterm birth.

Objectives To differentiate preterm (

OBJECTIVES To determine whether a novel, noninvasive quantitative ultrasound (US) technique can detect differences in proximal and distal cervical tissue echogenicity in women with and without a shortened cervical length (CL). METHODS We conducted a retrospective case-control study of singleton pregnancies at 16 to 26 weeks' gestation in which a transvaginal US examination was performed to measure CL from 2013 to 2015. Initial CLs in cases and controls were less than 2.5 cm and 2.5 cm or greater, respectively. For each US image, a region of interest was selected in the proximal and distal cervical stroma, in both the anterior and posterior cervical lips. The Floyd-Steinberg dithering algorithm transformed grayscale pixels in each region of interest into a binary map. A histogram tabulated the number of black and white pixels, allowing determination of the percent echogenicity. The difference in the percent echogenicity was calculated by subtracting the distal cervical echogenicity (average of anterior and posterior lips) from the proximal cervical echogenicity (average of anterior and posterior lips). RESULTS Ultrasound images from 177 women were analyzed. There was a difference in the percent echogenicity (P

OBJECTIVES The purpose of this study was to develop a novel method for creating an acellular bioactive scaffold, to prove its efficacy in vivo and in vitro for the augmentation of biological repair, and to confirm that sonographic microscopy is a viable modality for monitoring the healing process of osteochondral defects implanted with preconditioned bioactive scaffolds. METHODS Rabbit marrow stromal cells were retrovirally transduced with either bone morphogenetic protein 7 (BMP-7) or insulinlike growth factor 1 (IGF-1) genes, cultured for 9 weeks in nonwoven poly-L-lactic acid scaffolds, and then frozen and lyophilized. The knees were evaluated at 3, 6, and 12 weeks after surgery using 20-MHz ultrasound and then prepared for routine histologic analysis. B-scans of the extracellular matrix defects were compared to histologic results. RESULTS Control defects showed a void or a mixture of fibrocartilage tissue. Both types of scaffolds resulted in a higher percentage (both P< .001) of primarily hyaline cartilage tissue with intact articular surfaces. The osteochondral defects were clearly observed in each sonographic signature. There were no differences between images of scaffolds treated with IGF-1 or BMP-7. Extracellular matrix regrowth was found to closely parallel (R(2) = 0.968; P < .003) the histologic images. A 3-mm defect depth and a 2.5-mm scaffold thickness were measured on the sonograms, comparing well to actual dimensions. CONCLUSIONS There was a gradual increase in healing bordering the defects for the 3-, 6-, and 12-week samples. Also, we have shown that sonography can aid in monitoring implantation of preconditioned scaffolds in osteochondral defects and thus assessing the healing process and cartilage/bone quality.

Several imaging modalities have traditionally been utilized to assess bone health. However, none of these standards is capable of providing a clear rendition or display of the damaged bone layers caused, for instance, by osteoporosis. This study examines the use of ultrasound for non-invasive monitoring of bone quality in bone samples with various degrees of porosity. A user-defined region of interest (ROI) in the iliac portion of extracted human cadaver coxal bones is monitored and quantified. Raster C-scan images of the ROI were acquired and compared to basic physical measurements, and to bone scans using dual energy X-ray absorptiometry (DXA). A quantitative measure of the superficial sub-surface composite matrix (ScM) content was analyzed using linear regression with all physical and DXA measures. The trend in the degree of percent bone loss (PBL) measured by ultrasound (US) was found to be closely paralleled with that measured by DXA (R 2 = 0.82, p

Gross testicular heterogeneity on ultrasound has been associated with testis loss following testicular torsion in children. We aimed to quantify the extent of temporal heterogeneity associated with testis loss in testicular torsion cases using a noninvasive technique to determine a HI (heterogeneity index) on ultrasound images.We retrospectively studied the records of patients who presented with acute scrotal pain to the Pediatric Emergency Department over a 6-year period. Ultrasound images of the affected testis and the unaffected contralateral testis were examined using a proprietary program to determine the extent of heterogeneity of each image. The difference between the HI of the torsed testis and that of the contralateral normal testis was termed ΔHI. Receiver operating characteristics curve analysis was performed to determine the ΔHI threshold for nonviability.Among 529 patients who presented with acute scrotal pain 147 had testicular torsion based on surgical findings. Of these 147 patients 110 (74.8%) were found to have a viable testis while 37 (25.2%) had a nonviable testis. Using the ΔHI cutoff of 0.394 or greater for nonviability, sensitivity and specificity were 100% and 94.5%, respectively. Positive and negative predictive values were 86% and 100%, respectively.Our results demonstrate that a quantifiable temporal gradation of heterogeneity exists and the heterogeneity index can be used as an objective parameter to determine the viability of a torsed testicle. By developing the technology to measure the heterogeneity index in real time, we could potentially identify which patients with testicular torsion have a nonviable testicle and, thus, would not require immediate surgical exploration.

To differentiate preterm (37 weeks' gestation) from term (≥37 weeks' gestation) fetal lungs by using quantitative texture analysis of ultrasound images.This study retrospectively evaluated singleton gestations with valid dating at 20 weeks' gestational age (GA) or later between January 2015 and December 2015. Images were obtained from Voluson E8 ultrasound systems (GE Healthcare, Milwaukee, WI). A region of interest was selected in each fetal lung image at the level of the 4 heart chambers from an area that appeared most representative of the overall lung tissue and had the least shadow. Ultrasonic tissue heterogeneity (heterogeneity index) based on dynamic range calculation was determined for all lung images. This quantification was performed with a custom-made software program that used a dithering technique based on the Floyd-Steinberg algorithm, in which the pixels are transformed into a binary map. Regression analysis was used to determine the correlation and functional association between the heterogeneity index and GA. A receiver operating characteristic curve was used to identify the optimal heterogeneity index cutoff point for differentiating preterm from term fetal lungs.A total of 425 fetal lung ultrasound images (313 preterm and 112 term) were analyzed. Quantitative texture analysis predicted GA with sensitivity and specificity of 87.9% and 92.0%, respectively, based on the optimal receiver operating characteristic cutoff point.Quantitative ultrasound texture analysis of fetal lung tissue can differentiate preterm fetal lungs from term fetal lungs. Our data suggest that decreased fetal lung heterogeneity on ultrasound imaging is associated with preterm fetuses.

Although several imaging modalities have been utilized to observe tendons, assessing injured tendons by tracking the healing response over time with ultrasound is a desirable method which is yet to be realized. This study examines the use of ultrasound for non-invasive monitoring of the healing process of Achilles tendons after surgical transection. The overall extracellular matrix content of the transection site is monitored and quantified as a function of time. B-mode images (built from successive A-scan signatures) of the injury site were obtained and compared to biomechanical properties. A quantitative measure of tendon healing using the extracellular matrix (ECM) content of the injury site was analyzed using linear regression with all biomechanical measures. Contralateral tendons were used as controls. The trend in the degree of ECM regrowth in the 4 weeks following complete transection of excised tendons was found to be most closely paralleled with that of linear stiffness (R2 = 0.987, p

Anomalies present in the hard tissue of teeth are manifested in several ways such as cavities, decay, and caries. The most extensively and commonly used diagnostic modality for the assessment of these abnormalities are x-rays. Unfortunately, these rays are harmful to the human body and may be a source of health risk. This work describes the development of a new testing technique that uses ultrasound designed to complement, or even replace, existing tools used in dentistry applications. Previous studies have shown several models of acoustic field simulation, propagation, and interaction of ultrasound with the layers of several tooth structures. In this paper, experimental data is gathered for the purpose of assessing the viability of this technique in an attempt to detect cavities and fractures in extracted human teeth. A low-intensity, high-frequency ultrasonic set-up is used in all in vitro tests. Four cases have been examined: an intact tooth, a tooth containing an amalgam restoration and a natural surface fissure, a tooth containing a machine side-drilled hole that mimics a cavity, and a calcified tooth--a rare naturally occurring condition. Upon analysis of the obtained A-scans and B-scans, it is verified that these experimental measurements confirm predictions reported in earlier finite element and transmission line studies and suggest that ultrasound is a valuable tool which has the potential to be an addition to, or even an improvement upon, current dental imaging systems.

Ultrasound is used extensively in the medical field for the detection and characterization of a variety of features in the human body. Finite element models used to understand ultrasonic wave propagation in teeth have been developed so that ultrasound techniques could be realized in dentistry. This paper presents a hypothesis that underlies one possible design of an ultrasonic tool that can be used in a clinical environment, as well as several models that describe acoustic field simulation, propagation, and interaction with the layers of several tooth structures. A complete PSpice model of a single-element transducer based on Redwood's version of Mason's equivalent circuit, a focusing lens, and a multi-layer tooth structure is used to illustrate the validity of this hypothesis. Transmission line theory is employed as a basis for the models of the piezoceramic, the lens, and the different tooth layers. The results clearly depict the transmission and reflection of the ultrasonic waves as they travel through the layers within the tooth structure and point out the noticeable similarity to longitudinal L-wave signatures produced by axisymmetric finite element models presented in earlier studies.

Background Low-intensity ultrasound is considered an effective non-invasive therapy to stimulate hard tissue repair, in particular to accelerate delayed non-union bone fracture healing. More recently, ultrasound has been proposed as a therapeutic tool to repair and regenerate dental tissues. Our recent work suggested that low-frequency kilohertz-range ultrasound is able to interact with dental pulp cells which could have potential to stimulate dentine reparative processes and hence promote the viability and longevity of teeth. Methods In this study, the biophysical characteristics of low-frequency ultrasound transmission through teeth towards the dental pulp were explored. We conducted cell culture studies using an odontoblast-like/dental pulp cell line, MDPC-23. Half of the samples underwent ultrasound exposure while the other half underwent ‘sham treatment’ where the transducer was submerged into the medium but no ultrasound was generated. Ultrasound was applied directly to the cell cultures using a therapeutic ultrasound device at a frequency of 45 kHz with intensity settings of 10, 25 and 75 mW/cm2 for 5 min. Following ultrasound treatment, the odontoblast-like cells were detached from the culture using a 0.25% Trypsin/EDTA solution, and viable cell numbers were counted. Two-dimensional tooth models based on μ-CT 2D images of the teeth were analyzed using COMSOL as the finite element analysis platform. This was used to confirm experimental results and to demonstrate the potential theory that with the correct combination of frequency and intensity, a tooth can be repaired using small doses of ultrasound. Frequencies in the 30 kHz–1 MHz range were analyzed. For each frequency, pressure/intensity plots provided information on how the intensity changes at each point throughout the propagation path. Spatial peak temporal average (SPTA) intensity was calculated and related to existing optimal spatial average temporal average (SATA) intensity deemed effective for cell proliferation during tooth repair. Results The results demonstrate that odontoblast MDPC-23 cell numbers were significantly increased following three consecutive ultrasound treatments over a 7-day culture period as compared with sham controls underscoring the anabolic effects of ultrasound on these cells. Data show a distinct increase in cell number compared to the sham data after ultrasound treatment for intensities of 10 and 25 mW/cm2 (p < 0.05 and p < 0.01, respectively). Using finite element analysis, we demonstrated that ultrasound does indeed propagate through the mineralized layers of the teeth and into the pulp chamber where it forms a ‘therapeutic’ force field to interact with the living dental pulp cells. This allowed us to observe the pressure/intensity of the wave as it propagates throughout the tooth. A selection of time-dependent snapshots of the pressure/intensity reveal that the lower frequency waves propagate to the pulp and remain within the chamber for a while, which is ideal for cell excitation. Input frequencies and pressures of 30 kHz (70 Pa) and 45 kHz (31 kPa), respectively, with an average SPTA of up to 120 mW/cm2 in the pulp seem to be optimal and agree with the SATA intensities reported experimentally. Conclusions Our data suggest that ultrasound can be harnessed to propagate to the dental pulp region where it can interact with the living cells to promote dentine repair. Further research is required to analyze the precise physical and biological interactions of low-frequency ultrasound with the dental pulp to develop a novel non-invasive tool for dental tissue regeneration.

For quantitative nondestructive evaluation(QNDE) with using ultrasound, a new approach to improve spatial resolutions is presented in this paper. The newly implemented technique is compared with the synthetic aperture focusing technique(SAFT) and the Wiener filtering in the resolution and the signal-to-noise ratio. The approach provides with a much higher resolution than the SAFT and comparable resolution to the Wiener filtering, while it requires only one PSF. The images reconstructed by the technique, however, have a lower signal-to-noise ratio compared with that of the others.

Many innovations in the modern testing of materials make use of ultrasound. As a result, ultrasound has become extremely important to nondestructive testing of complete engineered systems. However, despite the fact that ultrasound inspection techniques are based on well-established principles, a few key problems pertaining to their application still remain unresolved. One of these problems deals with materials having complex geometries, often making the scanning/data collection processes time consuming. Consequently, fast and accurate mechanisms for testing components with awkward configurations have been the focus of attention in modern nondestructive testing research. In this paper, the data independent beamformer is studied as a potential method to reduce ultrasonic data acquisition time. The finite element method (FEM) is used as a testbed to mimic the ultrasound measurements by simulating the action of a transducer array. Tests reveal that when the weights of the interpolating filters (beamformers) are adjusted properly, they can indeed be used to predict A-scan signals from a data set produced by a transducer moving in a line-scan direction at nonuniform increments; hence, reducing the data acquisition time. The same filter weights also predict accurately A-scan signals from another data set produced by the same transducer moving at nonuniform increments for a different material geometry. >

This paper reviews diagnostic applications of ultrasound to dentistry, or dental ultrasonography, beginning with pioneering work of the 1960s up through present lines of research. Clinical, in vivo applications that are of direct interest to dental practice are reviewed here, including measurements of enamel thickness and periodontal pocket depth. In vitro research that involves destructive tooth preparation or procedures, such as sound speed measurements or scanning acoustic microscopy, also are included. Although dental ultrasonography has been studied for over 40 years, most methods are not quite ready for routine clinical use, and there remains much opportunity for diagnostic ultrasonography to significantly impact the practice of dentistry.

Ultrasound has been used extensively in medicine such as obstetrics and ophthalmology, and in the nondestructive testing of engineered materials such as isotropic and anisotropic composite structures. One area where ultrasound has found a new place for its application is dentistry. Several laboratory studies have shown great promise for this newly developed application. However, all of the inquiries assumed that the tooth is isotropic and homogeneous. The purpose of this project is to account for the multilayering and anisotropy nature of teeth by determining the phase velocities associated with several directions and orientations of ultrasonic wave propagation. Time-of-flight (TOF) information from A-scan signatures obtained at various angles of inclination and rotation are used in order to calculate the phase velocities. Slowness curves that would eventually lead to the determination of the independent elastic constants in human teeth are generated and reported in this paper.

Ultrasound imaging has been used widely for general medical diagnostics and in industry for the nondestructive detection and characterization of defects in critical engineering components. However, the lack of understanding of the fundamental wave propagation phenomena in teeth has largely precluded its application to dentistry. This paper describes how finite element (FEM) analysis can be used to study ultrasonic wave propagation in teeth. A three-layer tooth phantom based on the geometry of a human second molar is used to illustrate the validity of the tooth model. Results clearly indicate the finite element code's ability to predict and visualize ultrasonic wave propagation and interaction with dental anomalies, such as pulpitis, and that such results could be used to realize the design of appropriate transducers and equipment for dentistry applications.

Diagnostic ultrasound is being applied to teeth in order to detect cavities, decay, fractures and even early indication of abscesses. Ultrasonic waves are particularly sensitive to tight cracks and interface conditions between layers-dental features often difficult to interpret from X-ray images. Most importantly, due to its nonionizing nature, ultrasound acquires a potential advantage over conventional X-ray imaging. When ultrasonic waves are used at low intensity levels, they do not cause any health risks. This paper presents the results of laboratory experiments conducted on extracted human second and third molars using a low-intensity, high-frequency setup. Three cases have been examined: an intact tooth, a tooth containing an amalgam restoration, and a tooth containing a machine-side-drilled hole in order to mimic a cavity at the enamel-dentin interface. However, due to this paper length limitation only the first two cases are presented. A- and C-scans have been acquired in this study. Initial analysis of these results reveals similarities to those produced earlier by finite element and transmission-line methods insofar the identification of the different layers in the host teeth, and that such results could be used to realize the design of appropriate transducers and equipment for dentistry applications.

Ultrasound is used extensively in industry for the detection and characterization of defects in critical engineering structures. Similar techniques could be used in dentistry if a thorough understanding of ultrasonic wave propagation in teeth were available. This paper presents a hypothesis that finite element analysis can be used to solve the hyperbolic partial differential equation which governs ultrasonic wave propagation in teeth. A three-layer tooth phantom based on the geometry of a human second molar is used to illustrate the validity of this hypothesis. Simulated wave propagation studies are described for the tooth phantom with a gold crown layer, with an amalgam restoration insertion, and containing a cavity. Results clearly show the finite element code's ability to predict and visualize ultrasonic wave propagation in complex dental structures.

Although ultrasonic energy has been used widely for general medical diagnostic purposes and as a tool for the nondestructive inspection of engineering components, a lack of understanding of the fundamental wave propagation phenomena in teeth has largely precluded its application to dentistry. This paper studies the physics of ultrasound/teeth interactions. Based on the authors’ experience with the detection of defec engineering materials using ultrasound and the development of finite element computer code to study the wave propagation, initial studies have already been made on a tooth phantom. Results indicate that this numerical model can indeed be used to study the complex ultrasound interactions with dental anomalies, such as pulpitis and abscesses, and that such results could be used to optimize the design of appropriate transducers and equipment for dentistry applications. The primary reason why this technique is important and should take place is that ultrasonography has a great advantage over the presently available X-ray technology in that it does put any strain on the patient nor does it cause any pain. Most importantly, ultrasonic waves are nonionizing which, when used at low sound intensity levels, do not cause any health risks to the patient nor to the operator.

For quantitative nondestructive evaluation(QNDE) with using ultrasound, a new approach to improve spatial resolutions is presented in this paper. The newly implemented technique is compared with the synthetic aperture focusing technique(SAFT) and the Wiener filtering in the resolution and the signal-to-noise ratio. The approach provides with a much higher resolution than the SAFT and comparable resolution to the Wiener filtering, while it requires only one PSF. The images reconstructed by the technique, however, have a lower signal-to-noise ratio compared with that of the others.

Background The development of ultrasound for use in dental tissues is hampered by the complex, multilayered nature of the teeth. The purpose of this preliminary study was to obtain the phase and group velocities associated with several directions of ultrasonic wave propagation in relation to the tooth structure, which would then lead to the determination of the elastic constants in dental hard tissue. Knowledge of these elastic constants can be used to feed back into numerical models (such as finite element) in order to simulate/predict ultrasonic wave propagation and behavior in the teeth. This will help to optimize ultrasonic protocols as potential noninvasive therapeutic tools for novel dental regenerative therapies. Methods An extracted human second molar was used to determine time-of-flight information from A-scan signatures obtained at various angles of inclination and rotation using a scanning acoustic microscope at 10 MHz. Phase and group velocities and associated slowness curves were calculated in order to determine the independent elastic constants in the human teeth. Results Results show that as the tooth was inclined at three azimuthal angles (Θin = 0°, 15°, and 30°) and rotated from Φin = 0° to 360° in order to cover the whole perimeter of the tooth, slowness curves constructed from the computed phase and group velocities versus angle of rotation confirm the inhomogeneous and anisotropic nature of the tooth as indicated by the nonuniform appearance of uneven circular shape patterns of the measurements when compared to those produced in a control isotropic fused quartz sample. Conclusions This study demonstrates that phase and group velocities of ultrasound as determined by acoustic microscopy change and are dependent on the direction of the tooth structure. Thus, these results confirm that the tooth is indeed a multilayered anisotropic structure underscoring that there is no single elastic constant sufficient to represent the complex structure of the tooth. The findings underline the importance to take into account these crucial characteristics in order to develop and optimize therapeutic as well as diagnostic applications of ultrasound in dental tissue repair, and further studies are warranted to analyze ultrasound transmission at various frequencies and intensities in different teeth to develop appropriate models for ultrasound biophysical behavior in dental tissues.