Quantitative ultrasound tissue characterization in shoulder and thigh muscles--a new approach

High-frequency Quantitative Ultrasound Imaging of Human Rotator Cuff Muscles: Assessment of Repeatability and Reproducibility

This study evaluated the repeatability and reproducibility of using high-frequency quantitative ultrasound (QUS) measurement of backscatter coefficient (BSC), grayscale analysis, and gray-level co-occurrence matrix (GLCM) textural analysis, to characterize human rotator cuff muscles. The effects of varying scanner settings across two different operators and two US systems were investigated in a healthy volunteer with normal rotator cuff muscles and a patient with chronic massive rotator cuff injury and substantial muscle degeneration. The results suggest that BSC is a promising method for assessing rotator cuff muscles in both control and pathological subjects, even when operators were free to adjust system settings (depth, level of focus, and time-gain compensation). Measurements were repeatable and reproducible across the different operators and ultrasound imaging platforms. In contrast, grayscale and GLCM analyses were found to be less reliable in this setting, with significant measurement variability. Overall, the repeatability and reproducibility measurements of BSC indicate its potential as a diagnostic tool for rotator cuff muscle evaluation.

Mechanical characteristic of supraspinatus muscle changes independent of its size and intramuscular fat in patient with rotator cuff repair

PURPOSE

This study aimed i) to investigate the mechanical, morphological, and compositional characteristics of the supraspinatus muscle after rotator cuff repair by using ultrasound shear wave elastography (SWE) and B-mode imaging, and ii) to determine whether the morphological or compositional characteristics are associated with the mechanical characteristic of the supraspinatus during contraction.

METHODS

Using SWE and B-mode imaging, active and passive shear moduli, muscle thickness, and echo intensity of the supraspinatus were measured from the repaired and contralateral control shoulders of 22 patients with rotator cuff repair. The shear modulus, muscle thickness, and echo intensity were compared between the repaired and control shoulders. The association between the active shear modulus and the other variables was determined.

RESULTS

While the active and passive shear moduli were lower in the repaired shoulder compared to the control, the muscle thickness and echo intensity did not vary between them. Interestingly, the passive shear modulus was positively correlated with the active shear modulus only in the control shoulder.

CONCLUSION

The mechanical characteristic of supraspinatus remains impaired, even without degenerative changes in the morphological and compositional characteristics after rotator cuff repair. Furthermore, the association between contractile and elastic characteristics in the supraspinatus was deteriorated in control shoulder.

Skeletal Muscle Assessment Using Quantitative Ultrasound: A Narrative Review

Ultrasound (US) is an important imaging tool for skeletal muscle analysis. The advantages of US include point-of-care access, real-time imaging, cost-effectiveness, and absence of ionizing radiation. However, US can be highly dependent on the operator and/or US system, and a portion of the potentially useful information carried by raw sonographic data is discarded in image formation for routine qualitative US. Quantitative ultrasound (QUS) methods provide analysis of the raw or post-processed data, revealing additional information about normal tissue structure and disease status. There are four QUS categories that can be used on muscle and are important to review. First, quantitative data derived from B-mode images can help determine the macrostructural anatomy and microstructural morphology of muscle tissues. Second, US elastography can provide information about muscle elasticity or stiffness through strain elastography or shear wave elastography (SWE). Strain elastography measures the induced tissue strain caused either by internal or external compression by tracking tissue displacement with detectable speckle in B-mode images of the examined tissue. SWE measures the speed of induced shear waves traveling through the tissue to estimate the tissue elasticity. These shear waves may be produced using external mechanical vibrations or internal "push pulse" ultrasound stimuli. Third, raw radiofrequency signal analyses provide estimates of fundamental tissue parameters, such as the speed of sound, attenuation coefficient, and backscatter coefficient, which correspond to information about muscle tissue microstructure and composition. Lastly, envelope statistical analyses apply various probability distributions to estimate the number density of scatterers and quantify coherent to incoherent signals, thus providing information about microstructural properties of muscle tissue. This review will examine these QUS techniques, published results on QUS evaluation of skeletal muscles, and the strengths and limitations of QUS in skeletal muscle analysis.

Adolescent Marathon Training: Prospective Evaluation of Musculotendinous Changes During a 6-Month Endurance Running Program

OBJECTIVES

Assess changes in lower extremity musculotendinous thickness, tissue echogenicity, and muscle pennation angles among adolescent runners enrolled in a 6-month distance running program.

METHODS

We conducted prospective evaluations of adolescent runners' lower extremity musculotendinous changes at three timepoints (baseline, 3 months, and 6 months) throughout a progressive marathon training program. Two experienced researchers used an established protocol to obtain short- and long-axis ultrasound images of the medial gastrocnemius, tibialis anterior, flexor digitorum brevis, abductor hallicus, and Achilles and patellar tendons. ImageJ software was used to calculate musculotendinous thickness and echogenicity for all structures, and fiber pennation angles for the ankle extrinsic muscles. Repeated measures within-subject analyses of variance were conducted to assess the effect of endurance training on ultrasound-derived measures.

RESULTS

We assessed 11 runners (40.7% of eligible runners; 6F, 5M; age: 16 ± 1 years; running experience: 3 ± 2 years) who remained injury-free and completed all ultrasound evaluation timepoints. Medial gastrocnemius muscle (F_2,20  = 3.48, P = .05), tibialis anterior muscle (F_2,20  = 7.36, P = .004), and Achilles tendon (F_2,20  = 3.58, P = .05) thickness significantly increased over time. Echogenicity measures significantly decreased in all muscles (P-range: <.001-.004), and increased for the patellar tendon (P < .001) during training. Muscle fiber pennation angles significantly increased for ankle extrinsic muscles (P < .001).

CONCLUSIONS

Adolescent runners' extrinsic foot and ankle muscles increased in volume and decreased in echogenicity, attributed to favorable distance training adaptations across the 6-month timeframe. We noted tendon thickening without concomitantly increased echogenicity, signaling intrasubstance tendon remodeling in response to escalating distance.

Altered features of body composition in older adults with type 2 diabetes and prediabetes compared with matched controls

BACKGROUND

Ageing is accompanied by muscle loss and fat gain, which may elevate the risk of type 2 diabetes (T2D). However, there is a paucity of data on the distribution of regional lean and fat tissue in older adults with T2D or prediabetes compared with healthy controls. The objective of this study was to compare regional body composition [by dual-energy x-ray absorptiometry (DXA)], muscle and subcutaneous adipose tissue (SAT) thicknesses (by ultrasound), and ultrasound-based muscle texture features in older adults with T2D or prediabetes compared with normoglycaemic controls.

METHODS

Eighteen adults > 60 years with T2D or prediabetes (T2D group) were individually matched to normoglycaemic participants [healthy matched (HM) group] for age (±5 years), sex, and body fat (±2.5%). In a single study visit, all participants received a whole-body DXA scan and ultrasound assessment of the abdomen and anterior thigh. At these two landmarks, we used ultrasound to measure muscle and SAT thickness, as well as texture features of the rectus femoris and rectus abdominis. We also conducted an exploratory subanalysis on a subset of participants (n = 14/18 in the T2D group and n = 10/18 in the HM group) who underwent additional assessments including strength testing of the knee extensors (using a Biodex dynamometer), and a fasting blood sample for the measurement of circulating markers of glucose metabolism [glucose, insulin, c-peptide, and the homoeostatic model assessment of insulin resistance (HOMA-IR)].

RESULTS

The T2D group was 72 ± 8 years old (mean ± SD), predominantly male (n = 15/18; 83%), and overweight (BMI: 27.8 ± 4.2 kg/m² , 33.2 ± 5.3% body fat). DXA-derived upper arm lean mass was 0.4 kg greater (P = 0.034), and leg fat mass was 1.4 kg lower (P = 0.048), in the T2D vs. HM group. Ultrasound-based texture features were distinct between the groups [rectus abdominis blob size: 0.07 ± 0.06 vs. 0.30 ± 0.43 cm² , P = 0.045; rectus femoris local binary pattern (LBP) entropy: 4.65 ± 0.05 vs. 4.59 ± 0.08 A.U., P = 0.007]. When all participants who underwent additional assessments were pooled (n = 24), we observed that certain ultrasound-based muscle texture features correlated significantly with muscle strength (rectus abdominis histogram skew vs. power during an isokinetic contraction at 60°/s: r = 0.601, P = 0.003) and insulin resistance (rectus femoris LBP entropy vs. HOMA-IR: r = 0.419, P = 0.042).

CONCLUSIONS

Our findings suggest a novel body composition phenotype specific to older adults with T2D or prediabetes. We are also the first to report that ultrasound-based texture features correspond with functional outcomes. Future larger scale studies are needed to uncover the mechanisms underpinning these regional body composition differences.

Morphological and Functional Characteristics of the Peroneus Muscles in Patients with Lateral Ankle Sprain: An Ultrasound-Based Study

Background and Objectives: The effectiveness of multiple ultrasound evaluations of the peroneus muscles morphology, including muscle cross-sectional area (CSA) and connective tissue, after lateral ankle sprain (LAS) is unknown. This study aimed to measure the peroneus muscles after LAS at three points, adding distal 75% to the conventional measurement points, in order to obtain a detailed understanding of the post-injury morphology and to propose a new evaluation index of the peroneus muscles for multiple LAS. Materials and Methods: Participants with and without LAS (LAS and control groups, 16 each) were recruited. The muscle cross-sectional area (CSA) and muscle echogenicity were measured using a B-mode ultrasound system at 25%, 50%, and 75% proximal to the line connecting the fibular head to the lateral malleolus. The ankle evertor strength was measured using a handheld dynamometer. Simultaneously, the peroneus longus (PL) and peroneus brevis (PB) muscle activities were measured using surface electromyography. Measurements for the LAS side, non-LAS side, and control leg were performed separately. Results: The CSA was significantly higher at 75% on the LAS side than on the non-LAS side and in the control leg. Muscle echogenicity of the LAS side at 75% was significantly lower than that of the non-LAS side and the control leg. Muscle activity of the PL was significantly lower and the PB was higher on the LAS side than on the non-LAS side and in the control leg. Conclusions: The PL was less active than the PB, while the PB was found to be overactive, suggesting that PB hypertrophy occurs due to an increase in the percentage of muscle fibers and a decrease in the connective tissue. Therefore, it is necessary to evaluate the condition of the PL and PB separately after LAS.

Quantitative Ultrasound Texture Feature Changes With Conservative Treatment of the Trapezius Muscle in Female Patients With Myofascial Pain Syndrome

OBJECTIVE

We set out to assess whether quantitative ultrasound could be used to assess changes that occur after physical therapy in patients experiencing myofascial pain syndrome.

METHODS

We consecutively recruited female subjects experiencing myofascial pain syndrome of the neck and shoulder region and provided 10 sessions of conservative physical therapy. A control group was recruited for textural analyses. We measured change in pain ratings, range of motion, and ultrasound texture features before and after the intervention and after 3 mos.

RESULTS

We recruited 63 female myofascial pain syndrome subjects and 20 healthy controls. After treatment, the mean blob size (an ultrasound texture feature) value for each subject decreased from 30.84 ± 5.00 to 25.86 ± 5.67 on the right and decreased from 31.70 ± 5.51 to 28.08 ± 5.53 on the left (P < 0.0005). The blob count showed a significant increase only on the left side (P < 0.01). Corresponding to this were reductions in pain and disability scores after treatment and at 3 mos compared with retreatment (P < 0.0005 for all checkpoints). Cervical range of motion values were significantly increased only at 3 mos compared with pretreatment except for mean flexion range of motion.

CONCLUSIONS

Ultrasound texture feature of blob size and count changes correspond to routine clinical outcomes after conservative physical therapy of myofascial pain syndrome in female individuals.

Correlations between first order echotextural characteristics and chemical composition of pectoralis major muscles in broiler chickens receiving different dietary fat supplements

This study examined the quantitative relationships among ultrasonographic image attributes and chemical composition of the pectoralis major muscles in broiler chickens that received four different dietary fat supplements (Group SO: soybean oil; Group FO: flaxseed oil; Group SO+FO: soybean oil+flaxseed oil; and Group BT: beef tallow; n=10 birds/group). Ultrasonograms of birds’ pectoral muscles, in a transverse (T) and longitudinal (L) plane, were obtained just before slaughter at 6 weeks of age and were subjected to digital image analyses to determine mean pixel intensity (MPI) and pixel heterogeneity values (standard deviation of numerical pixel values; MPH; a.k.a first order echotextural characteristics). Thirty-eight chemical characteristics of the muscles were determined post-mortem (crude fat, protein, and dry matter as well as fatty acid profiles) and were analyzed for correlations with the echotextural variables. A total of 12 (L-MPI: 7; L-MPH: 4; and T-MPH: 1 correlation), 5 (L-MPI: 2; L-MPH: 2; and T-MPI: 1 correlation), 15 (L-MPI: 10; T-MPI: 4; and T-MPH: 1 correlation) and 8 (L-MPI: 2; L-MPH: 1; and TMPH: 5 correlations) significant correlations were recorded in Groups SO, FO, SO+FO and BT, respectively. When the data were pooled for all 40 birds studied, significant correlations with echotextural attributes were recorded for eighteen different chemical constituents, with the strongest overall correlation found between crude fat content and T-MPI (r=0.52, P=0.0005). In conclusion, there exists a potential application for ultrasonographic imaging in situ combined with computerized image analysis to estimate certain chemical constituents of pectoralis major muscles in broiler chickens. However, the existence and strength of correlations among ultrasonographic image attributes and muscle composition are affected by the source of dietary fat and relative abundance (“threshold concentrations”) of individual chemical components.

Muscle Composition Analysis of Ultrasound Images: A Narrative Review of Texture Analysis

Skeletal muscle composition, often characterized by the degree of intramuscular adipose tissue, deteriorates with aging and disease and contributes to impairments in function and metabolism. Ultrasound can provide surrogate measures of muscle composition through measurement of echo intensity; however, there are several limitations associated with its analysis. More complex image processing features, broadly known as texture analysis, can also provide surrogates of muscle composition and may circumvent some of the limitations associated with muscle echo intensity. Here, texture features from the intensity histogram, gray-level co-occurrence matrix, run-length matrix, local binary pattern, blob analysis, texture anisotropy index and wavelet analysis are discussed. The purpose of this review was to provide a conceptual understanding of texture analysis as it pertains to muscle composition of ultrasound images.

Effects of physical activity in muscle ultrasound evaluation of an older adult population – a pilot study

INTRODUCTION: Population aging has become an increasing challenge in society and inactive aging populations are especially challenging. OBJECTIVE: The main aim of this study is to conduct ultrasound evaluation of the effects of an intervention program on muscle architecture in older adults. METHODS: A total of thirty-four individuals of both sexes aged over 60 years were divided into two groups as follows: an intervention group (n = 18), who took part in a physical activity program for 8 weeks, three sessions per week, lasting approximately 20 min on each occasion, and a control group, whose members were encouraged to maintain their usual daily routines (outdoor aerobic exercise) (n = 16). Only six of the 18 participants from the intervention group were available for a second evaluation session. All the participants were submitted to bilateral quadriceps muscle ultrasound evaluations; thickness and echo-intensity of muscles were analyzed. RESULTS: Muscle thickness showed a significant negative correlation with age and echo-intensity showed a significant positive correlation with age. Echo-intensity showed a significant negative correlation with muscle thickness. Comparing the groups at the baseline evaluation, there were no significant differences between them (p < 0.05) for either measurement. CONCLUSIONS: We can highlight three points regarding post-intervention status in the intervention group: 1. There were significant differences in echo-intensity. It is therefore essential to establish early strategies to promote active aging, thus preventing dependence and inactivity in the older adult population; 2. Ultrasound is a good method for evaluating the musculoskeletal system and its changes in response to aging and physical activities; 3 Physical activities are important to maintain the muscles healthy and the older adult population independent.

Reliability of quantitative ultrasound measurement of flexor digitorum superficialis and profundus muscles in stroke

Aim: This study aims to investigate reliability of quantitative ultrasound measurement of the flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP) muscles in stroke. Materials & methods: Patients with a history of stroke were recruited. FDP and FDS muscles on both upper extremities were investigated with ultrasound. Two independent assessors acquired images and analyzed them using a program and Heckmatt scale. Results: Forty-eight patients were included. The inter-rater intraclass correlation coefficient for echo intensities was calculated as 0.91 while intrarater intraclass correlation coefficient as 0.80. For Heckmatt scale, the inter-rater reliability for FDS was Kw = 0.74 (p < 0.0005) and for FDP it was Kw = 0.73 (p < 0.0005). Mean echo intensity values showed significant strong correlations with Heckmatt scores (r = 0.663 and r = 0.633 with both p values <0.001). Conclusion: Quantitative ultrasound imaging of FDS and FDP is a reliable method to demonstrate echo intensity changes of muscles in stroke.

Proposing a Minimal Data Set of Musculoskeletal Ultrasound Imaging Biomarkers to Inform Clinical Practice: An Analysis Founded on the Achilles Tendon

Tendon integrity can be described using a wide range of biomarkers via specialized analysis software for images recorded by musculoskeletal ultrasonography. This study proposes a minimal biomarker data set to characterize Achilles tendon ultrasound images and to differentiate between symptomatic and asymptomatic Achilles tendon images. Forty-one individuals with unilateral Achilles tendinopathy and 35 healthy controls had their Achilles tendon images recorded bilaterally by ultrasonography in the longitudinal and transverse planes. A set of 22 biomarkers, organized around three dimensions (geometric, composition and texture), were computed in each plane. A symmetry index, reflecting relative side differences, was compared between groups and analyzed through principal component analysis to isolate biomarkers that best explained data variance. A specific minimal data set was identified by linear regression in the longitudinal (mean thickness, echogenicity, variance and homogeneity at 90°) and transverse (mean thickness, echogenicity and mean homogeneity) planes to characterize and differentiate Achilles tendon integrity.

Stiffness and echogenicity: Development of a stiffness-echogenicity matrix for clinical problem solving

The assessment of soft tissue stiffness is important to evaluate many neuromusculoskeletal conditions. Several tools have been proposed for the assessment of stiffness, but ultrasonography appears to be most practical. The reflection of ultrasound waves as it travels through tissue enables assessment of tissue echogenicity, which is influenced by the characteristics of the sound wave as well as the characteristics of the tissue through which it passes, such as the amount of fat and fibrous tissue. However, tissue stiffness is not directly proportional to its echogenicity. Hence evaluation of echogenicity, as a stand-alone technique, is inadequate to describe its mechanical properties. The aim of this manuscript is to present a method of combining echogenicity evaluation by ultrasound and stiffness evaluation by palpation to better describe the mechanical properties of muscle using a stiffness-echogenicity matrix.

Quantitative Echotextural Attributes of Pectoralis Major Muscles in Broiler Chickens: Physicochemical Correlates and Effects of Dietary Fat Source

Simple Summary

There is presently no method of predicting meat quality based on a single examination of birds before slaughter. That could potentially be accomplished with a computer-assisted analysis of ultrasonographic images. Hence, this experiment was designed to draw correlations between various physical and chemical properties of chicken pectoral muscles and pixel values (brightness elements) measured in corresponding ultrasonograms (a.k.a. echotexture). Our study revealed that echotextural characteristics of pectoral muscles in live birds were predictive of several important physical parameters (e.g., cutting force, hardness, and chewiness) as well as intramuscular fat and protein content. However, different dietary fats that caused changes in the chemical composition of chicken breast also affected the associations between muscle echotexture and its physicochemical properties. For example, no correlations with the chemical composition of the muscles could be found in birds fed with soybean oil. We concluded that ultrasonographic imaging combined with a computerized image analysis can offer significant benefits to the poultry industry and consumers. It can aid in livestock genetic selection and improvement programs as well as enhance the quality of poultry meat and meat products. However, more confirmatory studies are needed.

Abstract

This study examined the relationships among physicochemical properties and ultrasonographic image attributes of pectoralis major muscles in broiler chickens. Forty male Ross 308 chicks were randomly assigned to four equinumerous fat-supplementation groups (Group SO: soybean oil; Group FO: flax oil; Group SO + FO: soybean oil + flax oil; and Group BF: beef fat). Ultrasonograms of birds’ pectoral muscles were obtained just before slaughter at 6 weeks of age and were subjected to digital image analyses to determine the mean pixel intensity (MPI) and pixel heterogeneity values (standard deviation of numerical pixel values; MPH). A total of 2, 4, 2, and 6 significant correlations were recorded in Groups SO, FO, SO + FO, and BF, respectively; there were no correlations with the chemical composition of the muscles in Groups SO and SO + FO. The strongest correlations were found between muscle lightness (L*) and MPH in Group BF (physical characteristic; r = −0.82, p = 0.003), and between crude fat/protein content and MPI/MPH of pectoral the major muscles in Groups FO/BF (chemical characteristics; r = 0.72, p = 0.02). There exists a potential application of ultrasonographic imaging and computerized image analysis for predicting certain physicochemical properties of pectoralis major muscles in broiler chickens.

Assessing sarcopenia with vastus lateralis muscle ultrasound: an operative protocol

BACKGROUND

Muscle ultrasound (MUS) has so far not been implemented for sarcopenia assessment in clinical geriatric practice due to allegedly low reproducibility of results in the absence of standardization of procedures. However, rigorous and standardized application of this technique yields highly reproducible results. Its application, especially if integrated with clinical evaluation and comprehensive geriatric assessment, proofs very useful for rapidly obtaining information on muscle mass and architecture.

OBJECTIVE

Here, we present a standardized protocol for performing right vastus lateralis (RVL) MUS and measuring parameters of muscle size and architecture.

METHODS

RVL muscle thickness (MT), fascicle length (FL), pennation angle (PA), echo-intensity (EI) and cross-sectional area (CSA) can be assessed with this protocol. A portable instrument equipped with a 5-cm long 3-11 mHz linear probe should be used with both B-mode real-time and extended-field-of-view (EFOV) techniques. Longitudinal B-mode and transverse EFOV images should be acquired during each exam, and analyzed with NIH-ImageJ software.

CONCLUSIONS

This operative protocol represents a good compromise between the feasibility of MUS in clinical settings and the need of obtaining precise measurements of muscle parameters. Future studies should verify the reproducibility of the proposed technique, and its correlation with appendicular lean mass and parameters of muscle function.

Quantitative ultrasound of trapezius muscle involvement in myofascial pain: comparison of clinical and healthy population using texture analysis

PURPOSE

Ultrasound is a non-invasive quantitative method to characterize sonographic textures of skeletal muscles. To date, there is no information available on the trapezius muscle. This study assessed the trapezius muscles of patients with myofascial pain compared with normal healthy participants.

METHODS

The trapezius muscles of 15 healthy and 17 myofascial pain participants were assessed using B-mode ultrasound to obtain 120 images for healthy and 162 images from myofascial pain participants. Texture features such as blob area, count and local binary patterns (LBP) were calculated. Multi-feature classification and analysis were performed using principal component analysis (PCA) and MANOVA to determine whether there were statistical differences.

RESULTS

We demonstrate the two principal components composed of a combination of LBP and blob parameters which explain 92.55% of the cumulative variance of our data set. In addition, blob characteristics were significantly different between healthy and myofascial pain participants.

CONCLUSION

Our study provides evidence that texture analysis techniques can differentiate between healthy and myofascial pain affected trapezius muscles. Further research is necessary to evaluate the nature of these differences.

Quantitative Ultrasound Assessment of Myofascial Pain Syndrome Affecting the Trapezius: A Reliability Study

OBJECTIVES

Myofascial pain syndrome is one of the most common causes of chronic pain and is highlighted by the presence of myofascial trigger points. The current practice of diagnosing myofascial pain syndrome among clinicians involves manual detection of myofascial trigger points, which can be inconsistent. However, the detection process can be strengthened with the assistance of ultrasound (US). Therefore, this study aimed to characterize the upper trapezius by using quantitative techniques in healthy asymptomatic individuals with neck pain.

METHODS

Study participants were recruited on the basis of the inclusion and exclusion criteria established, and US images of the trapezius, along the axial and longitudinal orientations, were obtained. Each set was obtained by 2 investigators: experienced and inexperienced personnel.

RESULTS

Fifteen participants were recruited. The mean gray scale US echo intensity distribution obtained was 41.9. A paired t test of the global mean echo intensity value obtained for each image from the US operators did not show any significant difference (P = .77). A t test was performed, comparing the echo intensity of the group of patients with neck pain and healthy control participants, and the difference was found to be significant (P = .052). The median blob area was 2.71. The quartile range for the blob area was 1.72 for the 25th percentile to 4.90 for the 75th percentile.

CONCLUSIONS

This study demonstrated that quantitative analysis of the echo intensity of US images can provide important information. However, further research is necessary to explore the relationships among sex, age, blob area, count, body mass index, regional anatomy, and extent of training or exercise of the particular muscle.

Quantitative 3-D Ultrasound of the Medial Gastrocnemius Muscle in Children with Unilateral Spastic Cerebral Palsy

Three-dimensional ultrasound (3-DUS) was used to examine the size and appearance of the medial gastrocnemius (MG) muscle in children with unilateral cerebral palsy (CP). Twenty-six children with CP and 10 typically developing (TD) children participated. Three-dimensional US images of both limbs in children with CP and the right limb in TD children were analysed using quantitative methods to determine muscle volume, global echo intensity, global echo pattern and regional echo intensity. Significant differences in MG volume and all echo parameters were found between TD and CP children. The more involved limb was smaller and had higher echo intensity and a more heterogenous echo pattern compared with the TD group. Compared with that of the more involved limb, the MG of the less involved limb was larger but had a similar echo appearance. The MG of both limbs in children with unilateral spastic CP is smaller and, based on quantitative ultrasound, structurally different from that of TD children.

Forearm Flexor Muscles in Children with Cerebral Palsy Are Weak, Thin and Stiff

Children with cerebral palsy (CP) often develop reduced passive range of motion with age. The determining factor underlying this process is believed to be progressive development of contracture in skeletal muscle that likely changes the biomechanics of the joints. Consequently, to identify the underlying mechanisms, we modeled the mechanical characteristics of the forearm flexors acting across the wrist joint. We investigated skeletal muscle strength (Grippit®) and passive stiffness and viscosity of the forearm flexors in 15 typically developing (TD) children (10 boys/5 girls, mean age 12 years, range 8–18 yrs) and nine children with CP Nine children (6 boys/3 girls, mean age 11 ± 3 years (yrs), range 7–15 yrs) using the NeuroFlexor® apparatus. The muscle stiffness we estimate and report is the instantaneous mechanical response of the tissue that is independent of reflex activity. Furthermore, we assessed cross-sectional area of the flexor carpi radialis (FCR) muscle using ultrasound. Age and body weight did not differ significantly between the two groups. Children with CP had a significantly weaker (−65%, p < 0.01) grip and had smaller cross-sectional area (−43%, p < 0.01) of the FCR muscle. Passive stiffness of the forearm muscles in children with CP was increased 2-fold (p < 0.05) whereas viscosity did not differ significantly between CP and TD children. FCR cross-sectional area correlated to age (R² = 0.58, p < 0.01), body weight (R² = 0.92, p < 0.0001) and grip strength (R² = 0.82, p < 0.0001) in TD children but only to grip strength (R² = 0.60, p < 0.05) in children with CP. We conclude that children with CP have weaker, thinner, and stiffer forearm flexors as compared to typically developing children.

Quantitative ultrasound imaging of Achilles tendon integrity in symptomatic and asymptomatic individuals: reliability and minimal detectable change

Background

Quantifying the integrity of the Achilles tendon (AT) is a rehabilitation challenge. Adopting quantitative ultrasound measurements (QUS measurements) of the AT could fill this gap by 1) evaluating the test-retest reliability and accuracy of QUS measurements of the AT; 2) determining the best protocol for collecting QUS measurements in clinical practice.

Methods

A total of 23 ATs with symptoms of Achilles tendinopathy and 63 asymptomatic ATs were evaluated. Eight images were recorded for each AT (2 visits × 2 evaluators × 2 images). Multiple sets of QUS measurements were taken: geometric (thickness, width, area), first-order statistics (computed from a grayscale histogram distribution: echogenicity, variance, skewness, kurtosis, entropy) and texture features (computed from co-occurrence matrices: contrast, energy, homogeneity). A generalizability study quantified the reliability and standard error of measurement (accuracy) of each QUS measurement, and a decision study identified the best measurement taking protocols.

Results

Geometric QUS measurements demonstrated excellent accuracy and reliability. QUS measurements computed from the grayscale histogram distribution revealed poor accuracy and reliability. QUS measurements derived from co-occurrence matrices showed variable accuracy and moderate to excellent reliability. In clinical practice, using an average of the results of three images collected by a single evaluator during a single visit is recommended.

Conclusions

The use of geometric QUS measurements enables quantification of AT integrity in clinical practice and research settings. More studies on QUS measurements derived from co-occurrence matrices are warranted.

Age-related differences in the quantitative echo texture of the median nerve

OBJECTIVES

Currently, there are no quantitative data on the echo texture of a peripheral nerve. This study was designed to objectively compare the differences in the echo texture of the median nerve in the young and the elderly.

METHODS

The median nerves of 10 healthy young volunteers (<30 years old; group Y) and 10 elderly patients undergoing lower limb surgery (>60 years old; group E) were scanned at the mid forearm by a standardized protocol. The echo texture of a normalized median nerve image was analyzed for the echo intensity and spatial distribution of pixels. Noise in the image was reduced by using a median filter, and thresholding was performed thereafter. In the resultant binary image, the cross-sectional area, echo intensity, white area index, and black area index of the median nerve were determined by computerized texture analysis.

RESULTS

The mean cross-sectional area of the median nerve in group E was significantly smaller than that in group Y (P = .002). The mean echo intensity and white area index in group E were significantly higher than those in group Y (P= .002 and .012). The mean black area index in group E was correspondingly significantly lower than that in group Y (P = .012). In group Y, the mean white area index was significantly lower than the black area index (P = .006) but not in group E (P = .213).

CONCLUSIONS

There are significant differences in the echo texture of the median nerve between the young and the elderly. These differences may be due to age-related changes in the relative proportion of neural fascicles and connective tissue within the nerve.

Curvelet based automatic segmentation of supraspinatus tendon from ultrasound image: a focused assistive diagnostic method

Background

Disorders of rotator cuff tendons results in acute pain limiting the normal range of motion for shoulder. Of all the tendons in rotator cuff, supraspinatus (SSP) tendon is affected first of any pathological changes. Diagnosis of SSP tendon using ultrasound is considered to be operator dependent with its accuracy being related to operator’s level of experience.

Methods

The automatic segmentation of SSP tendon ultrasound image was performed to provide focused and more accurate diagnosis. The image processing techniques were employed for automatic segmentation of SSP tendon. The image processing techniques combines curvelet transform and mathematical concepts of logical and morphological operators along with area filtering. The segmentation assessment was performed using true positives rate, false positives rate and also accuracy of segmentation. The specificity and sensitivity of the algorithm was tested for diagnosis of partial thickness tears (PTTs) and full thickness tears (FTTs). The ultrasound images of SSP tendon were taken from medical center with the help of experienced radiologists. The algorithm was tested on 116 images taken from 51 different patients.

Results

The accuracy of segmentation of SSP tendon was calculated to be 95.61% in accordance with the segmentation performed by radiologists, with true positives rate of 91.37% and false positives rate of 8.62%. The specificity and sensitivity was found to be 93.6%, 94% and 95%, 95.6% for partial thickness tears and full thickness tears respectively. The proposed methodology was successfully tested over a database of more than 116 US images, for which radiologist assessment and validation was performed.

Conclusions

The segmentation of SSP tendon from ultrasound images helps in focused, accurate and more reliable diagnosis which has been verified with the help of two experienced radiologists. The specificity and sensitivity for accurate detection of partial and full thickness tears has been considerably increased after segmentation when compared with existing literature.

Quantitative ultrasound facilitates the exploration of morphological association of the long head biceps tendon with supraspinatus tendon full thickness tear

Backgrounds

Pathology of the long head biceps tendon (LHBT) is associated with rotator cuff tears but whether the LHBT texture changes following supraspinatus tendon full thickness tear (SSFT) can be detected at the extra-articular segment remains unknown. This cross-sectional study aimed to explore the morphological differences of the LHBT in shoulders with and without deficient rotator cuffs by using quantitative ultrasound.

Materials and Methods

We selected 145 cases with SSFT and 145 age-and- gender-matched controls. The width, thickness, flattening ratio, cross-sectional area, and echogenicity ratio of the LHBT were measured and a general linear model was used to clarify the relationship between rotator cuff pathology and LHBT morphology. The receiver operating characteristic curves of each parameter were constructed for SSFT discrimination and the maximal Youden indexes were used to define the best cut-off points.

Results

We found increased thickness and cross-sectional area but decreased flattening ratio in shoulders with SSFT, and no between-group differences in the width and echogenicity ratio. The LHBT appearance was modified by biceps peritendinous effusion and medial subluxation, but not by the size of SSFT. The flattening ratio was the best discriminator for SSFT with an area under curve of 0.81 (95% confidence interval, 0.76–0.86). The cut-off values to differentiate between the non-tear and tear groups were 2.00 mm of the thickness, 1.73 of the flattening ratio and 10.53 mm² of the cross-sectional area.

Conclusion

Quantitative ultrasound facilitated the detection of the LHBT morphological changes following SSFT and demonstrated its potential utility in discriminating rotator cuff deficiency.

Quantification of sonographic echogenicity by the gray-level histogram in patients with supraspinatus tendinopathy

PURPOSE

The aim of this study was to compare the gray-level value of the supraspinatus tendon of a painful shoulder with that of a normal shoulder measured by ultrasonography, and to investigate whether a low mean gray-level value of the supraspinatus tendon could indicate a partial-thickness or incomplete full-thickness tear.

METHODS

Two hundred and ten patients had significant unilateral shoulder pain with the clinical suspicion of rotator cuff tendinopathy. They underwent bilateral shoulder ultrasonography, and the mean echogenicity of the histogram was calculated on the screen. The mean gray-level value of each patient's contralateral asymptomatic shoulder was compared with that of the painful shoulder.

RESULTS

Based on the scan of transverse and longitudinal planes, a significant difference existed between the symptomatic shoulder and contralateral asymptomatic shoulder (p < 0.0001). The mean gray-level values of symptomatic shoulders showed no statistically significant difference between the patients who underwent surgery and the patients who underwent conservative treatment.

CONCLUSIONS

We demonstrated that the ultrasound gray-level histogram is a promising tool for detecting the hypoechogenic appearance of supraspinatus tendinopathy. A decrease in the mean gray-level value on the symptomatic shoulder may be used as an alternative sonographic indicator of rotator cuff partial-thickness tear or tendinopathy.

LEVEL OF EVIDENCE

Diagnostic level III.

Quantitative diagnostic method for biceps long head tendinitis by using ultrasound

Objective. 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. Setting. Outpatient rehabilitation service. Methods. 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. Results. 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. Conclusion. For equivocal cases or inexperienced sonographers, our study provides a more objective method for diagnosing biceps tendinitis in shoulder pain patients.

The effects of aging on quantitative sonographic features of rotator cuff tendons

PURPOSE

Grayscale analysis is a practical, objective, and easy way to quantify echogenicity during ultrasonography. The purpose of the current study was to measure the changes in thickness and echogenicity that result from aging of the rotator cuff and long head of the biceps tendons.

METHODS

The study comprised 45 volunteers, aged between 20 and 84 years and without history of shoulder pain. Participants were divided into three groups: young, middle-aged, and old. All subjects underwent standard ultrasonography of both shoulders. Tendon thickness and tear were recorded, and images in both transverse and longitudinal scans were taken for grayscale analysis. To reduce the attenuation effect from skin and subcutaneous fat, we used the ratio of echogenicity of the tendon to that of the reference muscle and compared the tendon echogenicity among the different age groups. Sonographic findings were also correlated with age.

RESULTS

The supraspinatus tendon was significantly thicker in elderly participants and this was positively correlated with age. Moreover, the echogenicity ratio of the supraspinatus tendon decreased in the elderly group and showed a negative correlation with age. There was a higher prevalence of supraspinatus tendon tears in the older participants.

CONCLUSIONS

Our results indicate that supraspinatus tendons became thickened, hypoechogenic, and more likely to tear with age. The study presents a simple and useful method to investigate the echogenicity of the rotator cuff quantitatively.

Ablation of leiomyomas using a combination of HIFU and iodized oil in vitro

This study investigates the enhancement effects of iodized oil and the features of hyperechoic focus changes in a target region of high-intensity focused ultrasound (HIFU) ablated uterine fibroids. Leiomyomas in the experimental group of 20 randomly assigned patients were ablated by HIFU under certain parameters 30 min after 1 mL of iodized oil was injected into the center of the myomas. The value of the gray scale and its area were observed by B-mode ultrasound in the target region and were carefully recorded at 0, 2, 4, and 5 min, respectively, after HIFU ablation. The samples were sectioned successively in a thickness of 1∼2 mm and stained by 2,3,5-triphenyltetrazolium chloride solution within 1 h after HIFU ablation. The TTC non-staining volumes were measured afterwards. All procedures in the control group of the other 20 randomly assigned patients were the same except that iodized oil was replaced by physiologic saline. The hyperechoic areas in the target region were observed in all fibroids of both groups. Compared with the control group, the gray scale values in the target region of the experimental group were higher 4 min after HIFU ablation. The enhanced gray scale area in the target region and the 2,3,5-triphenyltetrazolium chloride non-staining volumes in the experimental group were bigger. Based on our experience, HIFU sonication of leiomyomas injected with iodized oil produces hyperechoic foci that are greater than areas injected with saline. More studies are required to understand the clinical implications of these observations.

Validation of grayscale-based quantitative ultrasound in manual wheelchair users: relationship to established clinical measures of shoulder pathology

OBJECTIVE

The primary aim of this study is to establish the validity of grayscale-based quantitative ultrasound (QUS) measures of the biceps and supraspinatus tendons.

DESIGN

Nine QUS measures of the biceps and supraspinatus tendons were computed from ultrasound images collected from 67 manual wheelchair users. Shoulder pathology was measured using questionnaires, physical examination maneuvers, and a clinical ultrasound grading scale.

RESULTS

Increased age, duration of wheelchair use, and body mass correlated with a darker and more homogenous tendon appearance. Subjects with pain during physical examination tests for biceps tenderness and acromioclavicular joint tenderness exhibited significantly different supraspinatus QUS values. Even when controlling for tendon depth, QUS measures of the biceps tendon differed significantly between subjects with healthy tendons, mild tendinosis, and severe tendinosis. Clinical grading of supraspinatus tendon health was correlated with QUS measures of the supraspinatus tendon.

CONCLUSIONS

QUS is valid method to quantify tendinopathy and may allow for early detection of tendinosis. Manual wheelchair users are at a high risk for developing shoulder tendon pathology and may benefit from QUS-based research that focuses on identifying interventions designed to reduce this risk.

Reliability of quantitative ultrasound measures of the biceps and supraspinatus tendons

RATIONALE AND OBJECTIVES

Ultrasound is a proven method for examining soft tissue structures, including tendons, and recently quantitative ultrasound has become more prevalent in research settings. However, limited reliability data have been published for these new quantitative ultrasound measures. The main objective of this study was to quantify the reliability and measurement error of multiple quantitative ultrasound imaging protocols for the biceps and supraspinatus tendons.

MATERIALS AND METHODS

Two examiners captured ultrasound images of the non-dominant long head of the biceps tendon and supraspinatus tendon from 15 able-bodied participants and five manual wheelchair users. Each examiner captured two images per subject under two different preparations, which included subject positioning and reference marker placement. Image processing (reading) was performed twice to compute nine quantitative ultrasound measures of grayscale tendon appearance using first-order statistics and texture analysis. Generalizability theory was applied to compute interrater and intrarater reliability using the coefficient of dependability (Phi) for multiple study design protocols.

RESULTS

Interrater reliability was generally low (0.26 < Phi < 0.82), and it is recommended that a single evaluator capture all images for quantitative ultrasound protocols. Most of the quantitative ultrasound measures (n = 14 of 18) exhibited at least moderate (Phi > 0.50) intrarater reliability for a single image captured under one preparation and read once.

CONCLUSION

By following a protocol designed to minimize measurement error, one can increase the reliability of quantitative ultrasound measures. An appropriately designed protocol will allow quantitative ultrasound to be used as an outcome measure to identify structural changes within tendons.

High-resolution ultrasound and magnetic resonance imaging to document tissue repair after prolotherapy: a report of 3 cases

High-resolution ultrasound imaging of musculoskeletal tissue is increasing in popularity because of patient tolerability, low cost, ability to visualize tissue in real-time motion, and superior resolution of highly organized tissue such as a tendon. Prolotherapy, defined as the injection of growth factors or growth factor production stimulants to grow normal cells or tissue, has been a controversial procedure for decades; it is currently gaining in popularity among physiatrists and other musculoskeletal physicians. This report describes imaging of tendons, ligaments, and medial meniscus disease (from trauma or degeneration). Although these tissues have been poorly responsive to nonsurgical treatment, it is proposed that tissue growth and repair after prolotherapy in these structures can be documented with ultrasound and confirmed with magnetic resonance imaging. Directions for future research application are discussed.