Quantitative Ultrasound Method Research Articles

Association between sarcopenia and low back pain in local residents prospective cohort study from the GAINA study

BackgroundLow back pain (LBP) is one of the most common ailments that people experience in their lifetime. On the other hands, Sarcopenia also leads to several physical symptoms and contributes to reducing the quality of life of elderly people.The purpose of this study is to investigate the association between sarcopenia and low back pain among the general population.MethodsThe subjects included 216 adults (79 men and 137 women; mean age, 73.5 years) undergoing a general medical examination in Hino, Japan. Skeletal muscle index (SMI), The percentage of young adults’ mean (%YAM) of the calcaneal bone mass using with quantitative ultrasound (QUS) method and walking speed were measured, and subjects who met the criteria of the Asian Working Group for Sarcopenia were assigned to the sarcopenia group. Subjects with decreased muscle mass only were assigned to the pre-sarcopenia group, and all other subjects were assigned to the normal group. Then, we compared the correlations with low back pain physical finding. The Oswestry Disability Index (ODI) and the low back pain visual analogue scale (VAS) were used as indices of low back pain. Statistical analysis was performed among three groups with respect their characteristic, demographics, data of sarcopenia determining factor, VAS and ODI. We also analysed prevalence of LBP and sarcopenia. We investigated the correlations between ODI and the sarcopenia-determining factors of walking speed, muscle mass and grip strength.ResultsSarcopenia was noted in 12 subjects (5.5%). The pre-sarcopenia group included 38 subjects (17.6%), and the normal group included 166 subjects (76.9%). The mean ODI score was significantly higher in the sarcopenia group (25.2% ± 12.3%; P < 0.05) than in the pre-sarcopenia group (11.2% ± 10.0%) and the normal group (11.9% ± 12.3%). %YAM and BMI were significantly lower in the sarcopenia group than in other groups (P < 0.05). A negative correlation existed between walking speed and ODI (r = −0.32, P < 0.001).ConclusionsThe results of this study suggested that decreased physical ability due to quality of life in residents with LBP may be related to sarcopenia.

Impact of sol-gel transition on the acoustic properties of complex model foods: Application to agar/gelatin gels and emulsion filled gels

Quantitative Ultrasound techniques are good candidates for the in situ and real-time mechanical characterization of tongue-food-palate system, and thus to improve the understanding of the determinants of texture perception of food. Different model foods (consisting in gels and emulsion filled gels composed of agar and/or gelatin) have been designed for their contrasting properties in terms of texture perceptions. Prior to the feasibility study of a Quantitative Ultrasound method to monitor their mechanical breakdown during a compression, the aim of this study is to determine the respective roles of structure and mechanical properties of the different model foods in the variations of ultrasonic wave properties. Ultrasonic velocity, reflectivity, and attenuation were monitored during the sol-gel transition (from 50°C to 20°C) at 1 MHz in pulse-echo mode, and were confronted to visco-elastic moduli and mass density measurements. The results put in evidence the role of biopolymer concentration (independently from Young’s and shear moduli) on the variations of velocity and reflectivity, resulting from joint variations of mass density and bulk modulus. Moreover, the ultrasonic attenuation was confirmed to depend on molecular relaxation phenomena of water, which are important in high-concentration gelatin samples.

Comparison between the gold standard DXA with calcaneal quantitative ultrasound based-strategy (QUS) to detect osteoporosis in an HIV infected cohort

IntroductionOsteoporosis represents one of the most frequent comorbidity among HIV patients. The current standard method for osteoporosis diagnosis is dual-energy X-ray absorptiometry. Calcaneal quantitative ultrasound can provide information about bone quality. The aims of this study are to compare these two methods and to evaluate their ability to screen for vertebral fracture. MethodsThis cross-sectional study was conducted in HIV patients attending the Clinic of Infectious and Tropical Diseases of Brescia during 2014 and who underwent lumbar/femoral dual-energy X-ray absorptiometry, vertebral fracture assessment and calcaneal quantitative ultrasound. The assessment of osteoporosis diagnostic accuracy was performed for calcaneal quantitative ultrasound and for vertebral fracture comparing them with dual-energy X-ray absorptiometry. ResultsWe enrolled 73 patients and almost 48% of them had osteoporosis with at least one of the method used. Vertebral fracture were present in 27.4%. Among patients with normal bone measurements, we found vertebral fracture in proportion between 10% and 30%. If we used calcaneal quantitative ultrasound method and/or X-ray as screening, the percentages of possible savable dual-energy X-ray absorptiometry ranged from 12% to 89% and misclassification rates ranged from 0 to 24.6%. A combined strategy, calcaneal quantitative ultrasound and X-Ray, identified 67% of patients with low risk of osteoporosis, but 16.4% of patients were misclassified. ConclusionsWe observed that patients with osteoporosis determined by calcaneal quantitative ultrasound and/or dual-energy X-ray absorptiometry have higher probability to undergo vertebral fracture, but neither of them can be used for predicting vertebral fracture. Use of calcaneal quantitative ultrasound for screening is a reasonable alternative of dual-energy X-ray absorptiometry since our study confirm that none strategy is clearly superior, but both screen tools must be always completed with X-ray.

Normative data for quantitative calcaneal ultrasound in young males and females.

The quantitative ultrasound (QUS) method has been recognized as an optimal screening tool for assessing bone mass status. The aim of this study was to provide standardized values for bone health status measured by the QUS technique based on age, sex, and body mass index (BMI). The study population consisted of 1322 healthy individuals (822 females and 500 males) aged 14-25 years. Bone mass in both calcaneus was estimated with QUS to obtain Broadband ultrasound attenuation (BUA) (dB/MHz). The linear models revealed statistically significant differences between bone mass status of the calcaneus and age, sex, and BMI (P < .001). Bone mass increased at a rate of approximately 0.015 units per year after the age of 14 and these values increased in approximately 0.1 units in males in comparison to females. There was an increase of approximately 0.17 units for each increase in categories of BMI. It is crucial to provide standardized values for the QUS parameter in young males and females to allow reliable comparisons and evaluate trends in preventive programs that may enable the identification of individuals at risk for osteoporosis.

Ultrasonic Estimation of Volume Fraction of Kelvin Structure Using Micro-Structural Model

A quantitative ultrasound (QUS) method is developed for estimation of volume fraction of porous Kelvin structure to understand acoustic characteristics of trabecular bone. A Kelvin cellular specimen composed of isotropic tetra-kaidecahedron was produced by 3D printer with ABS plastic material to simulate artificial trabecular bone. The unit cell of Kelvin specimen has a size of 3.4mm and 81% of porosity. The specimen was completely filled with paraffin wax as a substitute of bone marrow. The speed of sound (SOS) of the wax-filled Kelvin specimen was measured using the time-of-flight (TOF) of ultrasound. Based on micro-structural model, shape parameters of Kelvin specimen is correlated with SOS and elastic constant to evaluate volume fraction of the specimen quantitatively. 25.8% of volume fraction was estimated for the Kelvin specimen which has actual volume fraction of 19%. It is concluded from experiment that the ultrasonic method developed in this study is effective and can be applied to diagnose and monitor osteoporosis.

Impact of isolated soy protein in non‐alcoholic fatty liver disease progression: monitored by a novel quantitative ultrasound (QUS) method

BACKGROUNDNon‐alcoholic fatty liver disease (NAFLD) is the most common liver disease in the Western world, affecting 20% of the population. If left untreated, NAFLD may progress into non‐alcoholic steatohepatitis (NASH), end‐stage liver disease or hepatocellular carcinoma. Emerging evidence indicates that soy protein may protect the liver from steatosis, which may improve health outcomes. We hypothesized that a soy protein intervention would be effective in protecting against further steatosis and disease progression in mice fed a high fat diet.METHODSIn this study, 8‐week‐old male C57BL/6J mice (n=70) were randomized onto an AIN‐93G control diet (CON, n=20) or a high‐fat atherogenic diet with a casein protein source (CAS, n=50). After 4 weeks on the CAS diet when animals were expected to develop NAFLD, CAS animals were randomized onto one of three diets: an atherogenic diet with a soy protein source (SOY, n=15), CAS (n=20) or the control diet (CAS‐CON, n=15). For this study, we utilized the novel non‐invasive QUS method developed by our lab in order to monitor hepatic fat content at various stages of steatosis. Each animal received liver ultrasound scans at baseline (in vivo) and at euthanasia (in vivo and ex vivo). At 4, 9 and 12 weeks on study, animals from each group were euthanized. At euthanasia, serum was collected and the liver was harvested. Half of the liver's left lateral lobe underwent hematoxylin and eosin (H&amp;E) staining (3‐μm section). The right cranial lateral liver lobe was removed for ex vivo QUS scanning. The remainder of each liver was frozen for further analysis.RESULTSLiver weight, as a percentage of body weight, was significantly increased with both atherogenic diets (CAS and SOY). CAS animals had significantly higher accumulation of lipids in the liver at each respective time point (p&lt;0.05) compared to either dietary control group (CON or CAS‐CON). CAS also had significantly higher serum cholesterol by week 12 compared to CON and CAS‐CON. The QUS was also significantly associated with the quantity of lipid in the liver. Ex vivo (p&lt;0.0001) and in vivo (p=0.047) ultrasound attenuation was positively correlated with liver lipids. Serum alanine aminotransferase (ALT) and histology will be analyzed to determine hepatic damage and disease status. QUS attenuation and backscatter will be further correlated to histological measures of steatosis, fibrosis and inflammation in the liver. Total hepatic cholesterol will also be measured.CONCLUSIONSAtherogenic diets were associated with an increase in liver weight, liver lipids and ultrasound attenuation. Replacing casein with soy as the protein source after four weeks of feeding failed to significantly reverse hepatic lipid accumulation or liver weight. QUS attenuation was significantly associated with hepatic lipid accumulation. Serum cholesterol increased over the course of 12 weeks in the CAS group. The development of a QUS method to identify early stages of NAFLD and NASH would provide the capability to noninvasively quantify and monitor liver status and evaluate methods for intervention.Support or Funding InformationThis work was supported by NIH R37EB002641 and by the USDA National Institute of Food and Agriculture, Hatch project 228706.

Comparison study of photoacoustic and ultrasound spectrum analysis in osteoporosis detection

Osteoporosis is a progressive bone disease, which is characterized by a decrease in the bone mass and deterioration in bone micro-architecture. In theory, photoacoustic (PA) analysis has the potential to obtain the characteristics of the bone effectively. In this study, we try to compare the PA spectral analysis (PASA) method with the quantitative ultrasound (QUS) method in osteoporosis assessment. We compare the quantified parameter slope from the PASA and broadband ultrasound attenuation from QUS among different bone models, respectively. Both the simulation and ex vivo experiment results show that bone with lower bone mineral density has the higher slope in the PASA method. Our comparison study proves that the PASA method has the same efficiency as QUS in osteoporosis assessment.

Acoustical estimation of endosseous implant stability: Finite element modeling and experimental validation

Various endosseous implants are widely used in orthopedic and dental surgeries. However, failures are observed, which may have dramatic consequences and are often due to a loss of implant stability. The aim of this presentation is to describe two acoustical methods developed to assess the stability of different implants. First, a quantitative ultrasound method was used to determine the stability of dental implants. A monoelement 10 MHz transducer is screwed into the implant and the signal is processed to obtain an indicator. The method was first validated in implants embedded in biomaterials used as bone substitutes, then in vitro and eventually in vivo by comparison with histology. A 3D FEM was developed to optimize the device conception and carry out sensitivity studies. Second, an impact hammer was used in order to investigate whether the AC implant primary stability can be evaluated using such approach. The method was first validated in vitro and in cadaveric experiments. The results showed that an in...

Deoxyribonucleic acid telomere length shortening can predict the incidence of non-alcoholic fatty liver disease in patients with type 2 diabetes mellitus.

Aims/IntroductionTo investigate the effect of telomere shortening and other predictive factors of non‐alcoholic fatty liver disease (NAFLD) in type 2 diabetes mellitus patients in a 6‐year prospective cohort study.Materials and MethodsA total of 70 type 2 diabetes mellitus (mean age 57.8 ± 6.7 years) patients without NAFLD were included in the study, and 64 of them were successfully followed up 6 years later, excluding four cases with significant alcohol consumption. NAFLD was diagnosed by the hepatorenal ratio obtained by a quantitative ultrasound method using NIH image analysis software. The 39 individuals that developed NAFLD were allocated to group A, and the 21 individuals that did not develop NAFLD were allocated to group B. Fluorescent real‐time quantitative polymerase chain reaction was used to measure telomere length.ResultsThere was no significant difference between the two groups in baseline telomere length; however, at the end of the 6th year, telomere length had become shorter in group A compared with group B. There were significant differences between these two groups in baseline body mass index, waistline, systolic blood pressure, glycated hemoglobin and fasting C‐peptide level. In addition, the estimated indices of baseline insulin resistance increased in group A. Fasting insulin level, body mass index, systolic blood pressure at baseline and the shortening of telomere length were independent risk factors of NAFLD in type 2 diabetes mellitus patients.ConclusionsTelomere length became shorter in type 2 diabetes mellitus patients who developed NAFLD over the course of 6 years. Type 2 diabetes mellitus patients who developed NAFLD had more serious insulin resistance compared with those who did not develop NAFLD a long time ago.

Early Detection of Nonalcoholic Fatty Liver Disease Utilizing a Novel QUS Method

Non‐alcoholic fatty liver disease (NAFLD) is the most common liver disease in the Western world, affecting 20% of the population. If left untreated, NAFLD may progress into non‐alcoholic steatohepatitis (NASH), end‐stage liver disease or hepatocellular carcinoma. While conventional ultrasound and other imaging techniques can diagnose advanced stages of fatty liver and hepatic cirrhosis, existing techniques are imprecise and not able to detect early stage NAFLD which may lead to a delayed diagnosis of complications. The goal of this study was to utilize the novel non‐invasive quantitative ultrasound (QUS) method to detect and quantify hepatic fat content at stages of steatosis. In a pilot study, 8‐week‐old male C57BL/67 mice were divided into one of three different dietary groups (n=15/group): control (Con) or one of two different atherogenic diets (Ath or Ath‐Casein). The control diet was a casein‐based purified diet (17.2% fat kcal). The Ath diet was a standard chow diet supplemental cocoa butter, cholesterol and sodium cholate (32.4% fat kcal). The Ath‐casein diet was a modification of the control diet supplemented with cocoa butter, sodium cholate and cholesterol (32.3% fat kcal). The livers of each animal received weekly ultrasound scans starting prior to being placed onto one of the three diets until euthanasia. Each week, five animals were euthanized. At euthanasia, serum was collected and the liver was harvested. Half of the liver's lateral left lobe was stained with H&amp;E (3‐μm section). Animals on the Ath‐Casein diet had significantly higher steatosis grading than animals on the Ath diet (P&lt;0.05) and control diet (P&lt;0.001). Lobular inflammation experienced a similar trend with inflammation being significantly increased in the Ath‐Casein (P&lt;0.001) and Ath (P&lt;0.01) diets compared to the control. Portal inflammation was statistically significant in both of the atherogenic diets compared to the control (P&lt;.001). Interestingly, a significant effect of liver cell injury was only visible in the Ath‐Casein group (P&lt;0.01 against Ath, and P&lt;0.0001 against control). Overall, histology revealed that animals on either of the atherogenic diets were in a worse metabolic condition. In vivo and ex vivo ultrasound of the liver display increased attenuation and backscatter in both of the atherogenic diets compared to the control. Total hepatic lipids were evaluated by the Folch method and will be further compared to ultrasound for trends corresponding to steatosis and inflammation in the liver. Total serum and hepatic cholesterol will be measured. Additionally, serum alanine aminotransferase (ALT) and tumor necrosis factor α (TNFα) will be analyzed to determine liver damage and systemic inflammation. The development of a QUS method to identify early stages of NAFLD and NASH would provide the capability to noninvasively quantify and monitor liver condition and test methods for intervention.Support or Funding InformationThis work was supported by NIH R37EB002641

A new perspective for lung ultrasonography, preliminary results

Lung ultrasonography (LUS) is increasingly applied for the diagnosis of lung diseases. However, diagnoses are often based on imaging artifacts, e.g., B-lines, ultimately being qualitative and subjective. Aiming at gaining insight on the genesis of B-line artifacts, and on their link to the anatomical structures related to pathological conditions, dedicated lung-mimicking phantoms were manufactured and imaged with the ULA-OP research platform, proving access to raw radio-frequency (RF) data. To mimic a healthy and a diseased lung, two phantom types were made, being gelatin phantoms containing bubbly-layers composed of mono-disperse microbubble populations of different diameters: 140 and 80 μm, respectively. In fact, in various pathological conditions the size of the alveoli (air sacs composing the lung parenchyma), and hence the lung volume occupied by air, is alterated due to, e.g., fluid extravasation, alveolar collapse, and inflammation. Results show the appearance of B-lines only for phantoms designed to mimic pathological condition, confirming the link between artifact formation and reduction of air spaces dimensions. These preliminary results may be applicable to LUS, opening the way to the development of a quantitative ultrasound method dedicated to the lung.

Assessment of liver fat content using quantitative ultrasonography to evaluate risks for metabolic diseases.

The ultrasound quantitative method for liver fat content (LFC) is a recent established method for non-invasive assessment of liver steatosis. Its use in clinical practice is further explored by investigating the quantitative relationships between LFC measured by quantitative ultrasonography and metabolic diseases in a middle-aged and elderly Chinese population. Liver fat content was measured by the quantitative ultrasound method in 4,916 participants from the Shanghai Changfeng Community Study. The anthropometric and serum biochemical parameters related to glucose and lipid metabolism were detected for each participant. The carotid artery intima-media thickness (CIMT) was measured by ultrasonography. The LFC displayed a non-Gaussian and positively skewed distribution in the community population and was significantly correlated with body weight, serum glucose, lipid profile, and CIMT. The 95th percentile of LFC in the subgroup of participants without any metabolic disease was 10.8%, and a LFC ≥ 10% was correlated with remarkable increases in the risks for glucose and lipid metabolic diseases. The quantitative ultrasound method that was developed for measuring LFC was useful in a population study. A LFC ≥ 10% might help to identify the subjects with an increased risk for metabolic diseases.

In vivo venous assessment of red blood cell aggregate sizes in diabetic patients with a quantitative cellular ultrasound imaging method: proof of concept.

BackgroundDiabetic patients present higher level of red blood cell (RBC) aggregation contributing to the development of vascular complications. While it has been suggested that this hematology/rheology parameter could bring additional prognostic information for the management of those patients, RBC aggregation screening is not included as a clinical practice. Most medical centers are not equipped to measure properly this parameter, although sedimentation tests can bring some indication. Here, we aimed at evaluating the feasibility of using ultrasound to assess in-vivo hyper-aggregation in type 2 diabetic patients.Research design and methodsSeventeen diabetic patients and 15 control subjects underwent ultrasound measurements of RBC aggregation in both cephalic and great saphenous veins. Non-invasive in-vivo ultrasound measurements were performed using a newly developed cellular imaging technique, the structure factor size and attenuation estimator (SFSAE). Comparisons with an ex-vivo gold standard rheometry technique were done, along with measurements of pro-aggregating plasma molecule concentrations.Results In-vivo RBC aggregation was significantly higher in diabetic patients compared with controls for cephalic vein measurements, while a trend (p = 0.055) was noticed in the great saphenous vein. SFSAE measurements were correlated with gold standard in-vitro measures, fibrinogen and C-reactive protein plasma concentrations.ConclusionRBC aggregation can be measured in-vivo in diabetic patients using ultrasound. Prospective studies are needed to determine whether the SFSAE method could help clinicians in the early management of vascular complications in this patient population.

Enhanced correlation between quantitative ultrasound and structural and mechanical properties of bone using combined transmission-reflection measurement.

Quantitative ultrasound (QUS) is capable of predicting the principal structural orientation of trabecular bone; this orientation is highly correlated with the mechanical strength of trabecular bone. Irregular shape of bone, however, would increase variation in such a prediction, especially under human in vivo measurement. This study was designed to combine transmission and reflection modes of QUS measurement to improve the prediction for the structural and mechanical properties of trabecular bone. QUS, mechanical testing, and micro computed tomography (μCT) scanning were performed on 24 trabecular bone cubes harvested from a bovine distal femur to obtain the mechanical and structural parameters. Transmission and reflection modes of QUS measurement in the transverse and frontal planes were performed in a confined 60° angle range with 5° increment. The QUS parameters, attenuation (ATT) and velocity (UV), obtained from transmission mode, were normalized to the specimen thickness acquired from reflection mode. Analysis of covariance showed that the combined transmission-reflection modes improved prediction for the structural and Young's modulus of bone in comparison to the traditional QUS measurement performed only in the medial-lateral orientation. In the transverse plane, significant improvement between QUS and μCT was found in ATT vs bone surface density (BS/BV) (p < 0.05), ATT vs trabecular thickness (Tb.Th) (p < 0.01), ATT vs degree of anisotropy (DA) (p < 0.05), UV vs trabecular bone number (Tb.N) (p < 0.05), and UV vs Tb.Th (p < 0.001). In the frontal plane, significant improvement was found in ATT vs structural model index (SMI) (p < 0.01), ATT vs bone volume fraction (BV/TV) (p < 0.01), ATT vs BS/BV (p < 0.001), ATT vs Tb.Th (p < 0.001), ATT vs DA (p < 0.001), and ATT vs modulus (p < 0.001), UV vs SMI (p < 0.01), UV vs BV/TV (p < 0.05), UV vs BS/BV (p < 0.05), UV vs Tb.Th (p < 0.01), UV vs trabecular spacing (p < 0.05), and UV vs modulus (p < 0.01). These data suggested that the combined transmission-reflection QUS method is capable of providing information more relevant to the structural and mechanical properties of trabecular bone.

Finite element simulation of ultrasonic wave propagation in a dental implant for biomechanical stability assessment.

Dental implant stability, which is an important parameter for the surgical outcome, can now be assessed using quantitative ultrasound. However, the acoustical propagation in dental implants remains poorly understood. The objective of this numerical study was to understand the propagation phenomena of ultrasonic waves in cylindrically shaped prototype dental implants and to investigate the sensitivity of the ultrasonic response to the surrounding bone quantity and quality. The 10-MHz ultrasonic response of the implant was calculated using an axisymetric 3D finite element model, which was validated by comparison with results obtained experimentally and using a 2D finite difference numerical model. The results show that the implant ultrasonic response changes significantly when a liquid layer is located at the implant interface compared to the case of an interface fully bounded with bone tissue. A dedicated model based on experimental measurements was developed in order to account for the evolution of the bone biomechanical properties at the implant interface. The effect of a gradient of material properties on the implant ultrasonic response is determined. Based on the reproducibility of the measurement, the results indicate that the device should be sensitive to the effects of a healing duration of less than one week. In all cases, the amplitude of the implant response is shown to decrease when the dental implant primary and secondary stability increase, which is consistent with the experimental results. This study paves the way for the development of a quantitative ultrasound method to evaluate dental implant stability.

Noninvasive Characterization of Locally Advanced Breast Cancer Using Textural Analysis of Quantitative Ultrasound Parametric Images

PURPOSE: The identification of tumor pathologic characteristics is an important part of breast cancer diagnosis, prognosis, and treatment planning but currently requires biopsy as its standard. Here, we investigated a noninvasive quantitative ultrasound method for the characterization of breast tumors in terms of their histologic grade, which can be used with clinical diagnostic ultrasound data. METHODS: Tumors of 57 locally advanced breast cancer patients were analyzed as part of this study. Seven quantitative ultrasound parameters were determined from each tumor region from the radiofrequency data, including mid-band fit, spectral slope, 0-MHz intercept, scatterer spacing, attenuation coefficient estimate, average scatterer diameter, and average acoustic concentration. Parametric maps were generated corresponding to the region of interest, from which four textural features, including contrast, energy, homogeneity, and correlation, were determined as further tumor characterization parameters. Data were examined on the basis of tumor subtypes based on histologic grade (grade I versus grade II to III). RESULTS: Linear discriminant analysis of the means of the parametric maps resulted in classification accuracy of 79%. On the other hand, the linear combination of the texture features of the parametric maps resulted in classification accuracy of 82%. Finally, when both the means and textures of the parametric maps were combined, the best classification accuracy was obtained (86%). CONCLUSIONS: Textural characteristics of quantitative ultrasound spectral parametric maps provided discriminant information about different types of breast tumors. The use of texture features significantly improved the results of ultrasonic tumor characterization compared to conventional mean values. Thus, this study suggests that texture-based quantitative ultrasound analysis of in vivo breast tumors can provide complementary diagnostic information about tumor histologic characteristics.

Ultrasonic evaluation of dental implant osseointegration

Dental implants are widely used for oral rehabilitation. However, there remain risks of failure which are difficult to anticipate and depend on the implant osseointegration. The objective of this in vivo study is to determine the variation of the echographic ultrasonic response of a dental implant to bone healing around the implant interface. Twenty one dental implants were inserted in the femur of seven New Zealand white rabbits. Two animals were sacrificed after a healing duration of two weeks, three animals after six weeks and six animals after eleven weeks. The 10MHz ultrasonic response of the implant was measured just after the implantation using a dedicated device positioned at the emerging surface of each dental implant. The measurements were realized again before the sacrifice with the same device. An indicator I˜ was derived based on the amplitude of the rf signal obtained for each configuration. The bone–Implant Contact (BIC) ratio was determined by histological analyses.The average value of the relative variation of the indicator I˜ obtained after initial surgery and after the corresponding healing period varies between 7% and 40%. A Kruskal–Wallis test (p<0.01) revealed a significant decrease of the value of the indicator I˜ as function of healing time. The indicator I˜ was significantly correlated (R²=0.45) with the BIC ratio. The results show that the ultrasonic response of a dental implant varies significantly as a function of healing time, which paves the way for the development of a new quantitative ultrasound (QUS) method in oral implantology.

Chest ultrasound in acute respiratory distress syndrome

This review discusses the role of chest ultrasound in diagnosis and management of acute respiratory distress syndrome (ARDS) and the most recent technical progresses in this field. Clinically, suspected ARDS can be easily confirmed by lung ultrasonography through the recognition of a typical pattern characterized by B-lines, spared areas, pleural line thickening, and subpleural consolidations. A visual score based on number and thickness of B-lines permits a semiquantitative evaluation of the amount of extravascular lung water and lung density. Recently, a quantitative lung ultrasound method has been proposed. The heart may be also involved in ARDS either primarily or by the application of positive pressure ventilation. The incidence of acute cor pulmonale during ARDS is, even if under protective ventilation, not negligible. The use of echocardiography combined with lung ultrasound is important for early detection of cor pulmonale, identification of the best ventilator strategy to preserve heart-to-lung interaction, and prediction of weaning success. An ultrasound-integrated approach combining lung ultrasound and echocardiography should be recommended as a suitable technique to manage ARDS during diagnosis, mechanical ventilation setting, and weaning.

Utility of C-terminal Telopeptide in Evaluating Levothyroxine Replacement Therapy-Induced Bone Loss

BACKGROUNDLevothyroxine (LT4) therapy has shown to have effects on bone metabolism though its deleterious effect on bone remodeling is debatable. This study was aimed at assessing the diagnostic utility of the bone remodeling marker C-terminal telopeptide (CTx) in detecting early bone loss.MATERIALS AND METHODSIn this case–control study, 84 premenopausal women of 30–45 years of age were selected. Out of them, 28 were recently diagnosed of hypothyroidism (not on LT4), 28 were on LT4 replacement therapy (100–200 μg/day) for more than five years, and 28 had euthyroid. Plasma CTx levels were estimated. Bone mineral density (BMD) was measured by quantitative ultrasound (QUS) method. Pearson’s coefficient of correlation and ANOVA were used for statistical analysis.RESULTSCTx was most elevated in LT4-treated group (0.497 ± 0.209 ng/mL). It showed a significant negative correlation with T-score and Z-score of BMD values. In the treatment group of more than 150 μg/day, CTx showed significantly negative correlation with TSH (r = −0.462, P = 0.047).CONCLUSIONLT4 therapy induces bone loss in hypothyroid patients. CTx levels can measure such bone loss along with BMD. Regular monitoring of CTx with adjustment in LT4 doses may help delay osteoporosis induced by prolonged LT4 replacement therapy.

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

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.