Ultrasound Echo Intensity Research Articles

A comparison of ultrasound echo intensity to magnetic resonance imaging as a metric for tongue fat evaluation.

Tongue fat is associated with obstructive sleep apnea (OSA). Magnetic resonance imaging (MRI) is the standard for quantifying tongue fat. Ultrasound echo intensity has been shown to correlate to the fat content in skeletal muscles but has yet to be studied in the tongue. The objective of this study is to evaluate the relationship between ultrasound echo intensity and tongue fat. Ultrasound coronal cross-sections of ex-vivo cow tongues were recorded at baseline and following three 1 mL serial injections of fat into the tongue. In humans, adults with and without OSA had submental ultrasound coronal cross-sections of their posterior tongue. The average echo intensity of the tongues (cow/human) was calculated in ImageJ software. Head and neck MRIs were obtained on human subjects to quantify tongue fat volume. Echo intensity was compared to injected fat volume or MRI-derived tongue fat percentage. Echo intensity in cow tongues showed a positive correlation to injected fat volume (rho = 0.93, p < .001). In human subjects, echo intensity of the tongue base strongly correlated with MRI-calculated fat percentage for both the posterior tongue (rho = 0.95, p < .001) and entire tongue (rho = 0.62, p < .001). Larger tongue fat percentages (rho = 0.38, p = .001) and higher echo intensity (rho = 0.27, p = .024) were associated with more severe apnea-hypopnea index, adjusted for age, body mass index, sex, and race. Ultrasound echo intensity is a viable surrogate measure for tongue fat volume and may provide a convenient modality to characterize tongue fat in OSA.

Associations between skeletal muscle echo intensity and thickness in relation to glucose homeostasis in healthy and glucose impaired older males.

Aging-related changes in muscle composition and mass may predispose older adults to developing insulin resistance. Ultrasound echo intensity and thickness are surrogates of muscle composition and mass, however, their associations with glucose homeostasis are not well established. We examined how muscle echo intensity and thickness correlate with markers of glucose homeostasis in older (≥65years) males with normal (n=22) or impaired (n=10) glucose control. Echo intensity was measured for the biceps brachii, rectus abdominis, and rectus femoris. Muscle thickness was evaluated for the biceps brachii + brachioradialis, rectus abdominis, and rectus femoris + vastus intermedius. Glucose homeostasis was evaluated using a 2-h oral glucose tolerance test. In older males with normal glucose homeostasis, higher echo intensity of the rectus abdominis and rectus femoris was moderately (r=0.36 to 0.59) associated with 2-h glucose. On the contrary, higher muscle echo intensity of the rectus abdominis, biceps brachii, and rectus femoris was moderately-to-strongly (r=-0.36 to -0.79) associated with indices of better glucose homeostasis in the impaired group. Rectus abdominis muscle thickness was moderately associated (r=0.36) with better glucose tolerance in the normal glucose homeostasis; however, in the glucose impaired group, muscle thickness was associated with (r=0.37 to 0.73) with poorer glucose homeostasis. Muscle echo intensity displays divergent associations with glucose homeostasis in older males with normal compared to impaired glucose control. Larger muscle thickness was associated with poorer glucose homeostasis in the glucose impaired group, but rectus abdominis muscle thickness was correlated with better homeostasis in healthy older males.

Ultrasound Imaging Analysis of the Lumbar Multifidus Muscle Echo Intensity: Intra-Rater and Inter-Rater Reliability of a Novice and an Experienced Rater

Background and Objectives: Ultrasound echo intensity (EI) of the lumbar multifidus muscle (LMM) could offer valuable insights regarding muscle quality in people with low back pain (LBP). However, whether the rater’s experience noticeably influences the reliability and precision of LMM EI measurements has not been established. The aims of this study were to investigate the intra-rater and inter-rater reliability of LMM EI measurements, and to compare the reliability and SEM between a novice and an experienced rater. Materials and Methods: Twenty athletes (10 females, 10 males) with a history of LBP were included in this study. Transverse ultrasound images of LMM were taken at L5 in prone. LMM EI measurements were obtained bilaterally by tracing the maximum ROI representing the LMM cross-sectional area (CSA), avoiding the inclusion of bone or surrounding fascia. All measurements were performed by two novice raters and an experienced researcher. Each measurement was acquired by each rater three times for each side on three different images, and the average was used in the analyses. Raters were blinded to each other’s measurements and the participant’s clinical information. Intra-class correlation coefficients (ICCs) were obtained to assess the intra-rater and inter-rater reliability. Results: The intra-rater ICC values for the LMM measurements for the experienced rater were excellent (ICC all > 0.997). The inter-rater reliability ICC values showed moderate to excellent reliability (0.614 to 0.994) and agreement between the novice raters and the experienced rater, except for Novice 1 for the right LMM, which revealed lower ICCs and a wider 95% CI. Intra-rater and inter-rater reliability results were similar when separately looking at the right and left side of the muscle and participant gender. Conclusions: Our findings support the clinical use of ultrasound imaging for the assessment of LMM EI in individuals with LBP.

Associations between sagittal plane walking kinematics and femoral cartilage ultrasound echo-intensity in individuals with symptomatic radiographic knee osteoarthritis

Purpose: Ultrasound (US) has recently emerged as a valid and reliable tool for assessing femoral articular cartilage. Previous US studies have demonstrated that individuals with knee OA exhibit thinner cartilage with greater irregularities on the cartilage borders and more irregular femoral cartilage compared to healthy age-matched controls. Similarly, US echo-intensity (EI) values for cartilage are higher in individuals with knee OA compared to healthy controls, which may reflect alterations in femoral articular cartilage, such as an increase in the relative water content of the tissue.

Examination of the confounding effect of subcutaneous fat on muscle echo intensity utilizing exogenous fat.

We aimed to provide an unbiased estimate of the confounding effect of subcutaneous fat thickness on ultrasound echo intensity (EI) measures of muscle quality. The effect of fat thickness on EI was verified for an approximate range of 0 to 3 cm of fat using exogeneous layers of pork fat over the human tibialis anterior muscle. Sonograms were obtained (i) with focus constant across fat thickness conditions, and (ii) with focus position adjusted to the muscle region of interest (ROI) position for each fat thickness level. In agreement with our hypothesis, increasing fat between the probe and the ROI resulted in a decrease in EI. This overestimating effect of fat on muscle quality differs between sonograms with constant focus and sonograms with focus position adjusted to the vertical displacement in ROI position that occurs for different levels of fat thickness. Correcting equations to account for the overestimating effect of fat on muscle quality are provided for both focus conditions. This is the first study to systematically analyze the confounding effect of fat thickness as an independent factor and the provided equations can be used for improved accuracy in estimates of muscle quality in obese/overweight subjects/patients. Novelty: The independent confounding effect of subcutaneous fat thickness on ultrasound (US) estimates of muscle quality was quantified. US estimates of muscle quality depend on whether focus is adjusted to the muscle region of interest or not. Equations for correcting muscle quality estimates are provided.

Femoral Cartilage Ultrasound Echo Intensity Associates with Arthroscopic Cartilage Damage

This study compared quantitative cartilage ultrasound metrics between people with (n = 12) and without (n = 12) arthroscopic cartilage damage after anterior cruciate ligament injury (age, 24.9 ± 3.7 y; sex, 33% female, 67% male; days since injury = 50 ± 52). A transverse suprapatellar ultrasound assessment imaged the femoral cartilage in participants’ injured knees before a clinical arthroscopy. A custom program automatically separated a manual cartilage segmentation into standardized medial and lateral femoral regions and calculated mean thickness (i.e., cross-sectional area/length of cartilage-bone interface), mean echo intensity and echo-intensity heterogeneity. An orthopedic surgeon assessed arthroscopic cartilage damage in the medial and lateral femoral condyles using the Outerbridge grading system (cartilage damage = Outerbridge ≥ 1). Separate logistic regressions for medial and lateral femoral cartilage were used to determine the association between each ultrasound metric and arthroscopic cartilage damage. In medial femoral cartilage, for every 1 standard deviation decrease in echo-intensity mean and heterogeneity, there is, respectively, a 91% (adjusted odds ratio, 0.09; 95% confidence interval, 0.01–0.69) and 97% (adjusted odds ratio, 0.03; 95% confidence interval, 0.002–0.50) increase in the odds of having arthroscopic cartilage damage. Lateral cartilage ultrasound metrics are not associated with lateral arthroscopic cartilage damage. This study provides preliminary evidence that femoral cartilage ultrasound echo intensity is a non-invasive measure associated with medial femoral cartilage health after anterior cruciate ligament injury.

Influence of muscle depth and thickness on ultrasound echo intensity of the vastus lateralis.

Ultrasonography is used to evaluate muscle quality (i.e. echo intensity [EI]), but an attenuation of ultrasound waves occurs in deeper tissues, potentially affecting these measures. To determine whether muscle thickness (MT) affects EI and if EI varies between the superficial and deep portions of the muscle. MT, EI, subcutaneous adipose tissue thickness (SAT), tissue depth (DISDEEP), and EI of the overall (EIFULL) as well as deep (EIDEEP) and superficial (EISUPF) portions of the vastus lateralis (VL) were assessed in 33 resistance-trained males using ultrasonography. The difference (EIDIFF) between EISUPF and EIDEEP was calculated. Mean differences between EIFULL, EISUPF, and EIDEEP were analyzed using a repeated-measures analysis of variance (ANOVA). Relationships between measures of muscle depth/ thickness and EI were examined using Pearson's r. EISUPF was greater than EIDEEP (P < 0.001) and EIFULL (P < 0.001). MT was negatively correlated with EIFULL (P < 0.001) and positively correlated with EIDIFF (P < 0.001). SAT was not correlated with any EI measure, but DISDEEP was positively correlated with EIDIFF (P < 0.001). EI of the VL is heterogeneous, as the deeper portion produces lower values than the superficial portion. Thicker muscles present lower EI but have greater discrepancies in EI between the superficial and deep portions. Although SAT was not correlated with EI, DISDEEP was related to EIDIFF, demonstrating that the combination of MT and SAT should be considered when evaluating muscle quality. Future research is necessary to determine if changes in EI following resistance training are driven by increases in MT.

Longitudinal Relationship Between Intramuscular Fat in the Quadriceps and Gait Independence in Convalescent Stroke Patients

Background and AimIn a cross-sectional study, intramuscular fat in the quadriceps of stroke patients has been associated with gait independence. However, the longitudinal relationship between intramuscular fat and gait independence remain unclear. If these relationships are clarified, it can be demonstrated that improvement in gait independence eventually contributes to improved intramuscular fat in the quadriceps of stroke patients. The aim of this study was to investigate the longitudinal relationship between intramuscular fat in the quadriceps and gait independence in convalescent stroke patients. MethodsEleven stroke patients participated in this study. Gait independence was assessed using the Functional Independence Measure (FIM) gait score. The intramuscular fat in the quadriceps was assessed using ultrasound echo intensity, whereas higher echo intensity indicated greater intramuscular fat. The baseline and discharge assessment values for the echo intensity of the quadriceps were compared using a paired t-test. Correlation analysis of the FIM gait score gain and echo intensity changes in the quadriceps on the paretic and non-paretic sides was performed using Kendall's rank correlation coefficient. ResultsFor quadriceps on the paretic side, echo intensity values at discharge were significantly lower than those at admission. However there was no significant difference for quadriceps on the non-paretic side (paretic side: 19.9% decrease; non-paretic side: 8.0% decrease). We observed that the change in the echo intensity of quadriceps on the non-paretic side was negatively corelated with FIM gait score gain. ConclusionsOur results revealed a strong correlation between longitudinal change in intramuscular fat in the quadriceps and gait independence, implying that improved gait independence in convalescent stroke patients might have a positive effect on improvements in intramuscular fat.

Evaluation of lymphocytic thyroiditis in children with quantitative gray-scale ultrasound echo intensity using a PACS-based tool

PurposeTo evaluate diagnostic performance of PACS-based quantitative gray-scale ultrasound as an objective method in evaluation of pediatric thyroiditis. MethodsQuantitative measurements of the echo-intensity level of the thyroid were obtained from ultrasound images, retrospectively using a PACS-based tool in 37 children with the tissue-proven diagnosis. Thyroid/muscle ratio was calculated by dividing the mean echo intensity of thyroid by that of adjacent strap muscle. Heterogeneity index (HI) was calculated by dividing thyroid standard deviation (SD) by thyroid mean values. For qualitative evaluation, two radiologists independently reviewed ultrasounds twice for the presence of thyroiditis. A consensus session was performed for patients for whom there was disagreement. Intra- and inter-observer reliability were assessed. Thyroid/muscle ratio and HI were correlated with final pathology. ResultsLymphocytic thyroiditis was found by histopathology in 19/37 (51%). No significant difference between thyroiditis and normal thyroid groups was found for either thyroid/muscle ratio (1.51 and 1.62, respectively, p = .82) or HI (0.23 and.23, respectively, p = .37). A larger proportion of patients for whom the consensus review indicated thyroiditis were confirmed by histopathology than would be expected by chance alone (12/19 (63%), p = .03). There was fair inter-observer agreement (κ with 95% confidence intervals of 0.36 (0.14–0.57), p = .004) and slight intra-observer agreement for each radiologist (κ with 95% confidence intervals of 0.13 (0.17–0.43), p = .39 and 0.17 (0.15–0.49), p = .31). ConclusionQuantitative gray-scale echo intensity analysis of US was not sufficient to diagnose thyroiditis in a pediatric population. Consensus qualitative analysis of ultrasound was more consistent with pathological diagnosis.

Ultrasound echo intensity of cervical muscles in women with and without forward head posture

ABSTRACT Objective: Forward head posture (FHP) is a common abnormal posture in neck disorders. FHP causes an alteration of the strength in the cervical muscles. Since both muscle quantity and quality impress the muscle strength, this study aimed to compare the echo intensity of cervical muscles (index of muscle quality) between women with and without FHP. Method: Echo intensity of cervical muscles was measured by Adobe Photoshop software and compared between two groups. Results: The findings of the current study indicate the insignificant difference between two groups regarding the echo intensity of cervical muscles. Conclusion: Evaluation of echo intensity of cervical muscles may expand knowledge about the muscle quality and function.

Ultrasound-based cartilage outcomes differentiate healthy and medial femoral cartilage damage after anterior cruciate ligament injury: A preliminary investigation

Purpose: Ultrasound imaging is a clinically feasible tool to assess femoral articular cartilage following acute knee injuries. Previous studies have validated an ultrasound assessment of femoral cartilage thickness. However, traditional ultrasound cartilage thickness assessments rely on a single straight-line distance and do not determine the mean thickness throughout a cartilage region. Further, it is unknown whether ultrasound echo-intensity (i.e., magnitude and variation of the pixel signal intensity) is related to cartilage damage following anterior cruciate ligament injury.

Comparison between high- and low-intensity eccentric cycling of equal mechanical work for muscle damage and the repeated bout effect.

We compared high- and low-intensity eccentric cycling (ECC) with the same mechanical work for changes in muscle function and muscle soreness, and examined the changes after subsequent high-intensity ECC. Twenty men performed either high-intensity ECC (1min × 5 at 20% of peak power output: PPO) for two bouts separated by 2weeks (H-H, n = 11), or low-intensity (4min × 5 at 5% PPO) for the first and high-intensity ECC for the second bout (L-H, n = 9). Changes in indirect muscle damage markers were compared between groups and bouts. At 24h after the first bout, both groups showed similar decreases in maximal isometric (70° knee angle, - 10.6 ± 11.8%) and isokinetic ( - 11.0 ± 8.2%) contraction torque of the knee extensors (KE), squat ( - 7.7 ± 10.4%) and counter-movement jump ( - 5.9 ± 8.4%) heights (p < 0.05). Changes in KE torque and jump height were smaller after the second than the first bout for both the groups (p < 0.05). Increases in plasma creatine kinase activity were small, and no significant changes in vastus lateralis or intermedius thickness nor ultrasound echo-intensity were observed. KE soreness with palpation was greater (p < 0.01) in H-H (peak: 4.2 ± 1.0) than L-H (1.4 ± 0.6) after the first bout, but greater in L-H (3.6 ± 0.9) than H-H (1.5 ± 0.5) after the second bout. This was also found for muscle soreness with squat, KE stretch and gluteal palpation. The high- and low-intensity ECC with matched mechanical work induced similar decreases in muscle function, but DOMS was greater after high-intensity ECC, which may be due to greater extracellular matrix damage and inflammation.

Tendon morphological changes after a prolonged ski race can be detected by ultrasound echo intensity

BackgroundUltrasound imaging techniques have been used to assess the characteristics of skeletal muscles and tendons. Such techniques (gray scale analysis) allow qualitative evaluation and have been used recently to assess the internal structure of muscles and tendons by computer-aided gray scale analysis. We hypothesized that changes in the internal structure of the Achilles and patellar tendons after a ski mountaineering race competition could be detected with ultrasound.MethodsTwenty athletes were recruited during the 19th Millet Tour du Rutor extreme, a three-day ski mountaineering competition. Ultrasound measurements of the Achilles and patellar tendons were carried out before the first race and immediately after each of the three competition days. Tendon thickness, cross-sectional area (CSA), and ultrasound gray scale analysis were calculated.ResultsSignificant differences (p < 0.05) were observed between the pre- and post-race measurements for the Achilles tendon thickness and CSA, while no significant differences were noted for the patellar tendon thickness and CSA. However, gray scale analysis of both the Achilles and patellar tendons showed significantly higher post-race values, than the pre-race values (p < 0.05).ConclusionsAchilles and patellar tendons of healthy athletes are highly responsive to an acute increase in mechanical load. Those changes can be detected from classical (thickness and CSA) and innovative (gray scale) ultrasound-based parameters.Trial registrationThis study was approved by the Azienda USL Valle d’Aosta Ethics Committee (protocol no. 23/03/2018.0026243.I).

Higher malnutrition risk is related to increased intramuscular adipose tissue of the quadriceps in older inpatients: A cross-sectional study.

The relationship between malnutrition risk and intramuscular adipose tissue of the quadriceps in older inpatients remains unclear, although a high rate of malnutrition risk has been observed in these patients. Understanding this relationship would be necessary for a management plans for older inpatients. This study aimed to examine the relationship between malnutrition risk and intramuscular adipose tissue of the quadriceps in older inpatients. Three-hundred and twenty-three older inpatients participated in this cross-sectional study. Malnutrition risk was assessed using the Geriatric Nutritional Risk Index (GNRI). Intramuscular adipose tissue of the quadriceps was assessed based on ultrasound echo intensity. Higher echo-intensity indicates greater amounts of intramuscular adipose tissue. Multiple regression analysis was used to identify the factors that were independently associated with quadriceps echo intensity. GNRI, age, sex (male=1, female=2), number of medications, C-reactive protein, updated Charlson comorbidity index, Food Intake Level Scale, the subcutaneous fat thickness of the thigh, motor-Functional Independence Measures, and length of hospital stay were set as the independent variables. GNRI (β=-0.18), age (β=0.18), sex (β=0.22), number of medications (β=0.09), the subcutaneous fat thickness of the thigh (β=-0.29), motor-FIM (β=-0.12), and length of hospital stay (β=0.11) were significantly and independently associated with the quadriceps echo intensity. The current results revealed that higher malnutrition risk was associated with increased intramuscular adipose tissue of the quadriceps of older inpatients even after adjusting for other characteristics. Nutritional intervention may be necessary for decreasing intramuscular adipose tissue of the quadriceps in older inpatients who have higher malnutrition risk.

Acute effect of multiple sets of fatiguing resistance exercise on muscle thickness, echo intensity, and extracellular-to-intracellular water ratio.

Resistance exercise (RE) causes an acute increase of the muscle thickness (MT) considered to relate to an increase in tissue water content. Segmental bioelectrical impedance spectroscopy (S-BIS) is a tool used to noninvasively assess intra- and extra-cellular water (ICW and ECW, respectively) of a given limb segment. The purpose of the present study was to examine the change of MT, ultrasound echo intensity (EI), ICW, and ECW after 3 sets of exhaustive RE. Eighteen untrained young males (age, 25.4 ± 4.1 years) performed RE consisting of 3 sets of knee extension concentric and eccentric contractions with 80% of 1-repetition maximum to failure. The MT and EI of the quadriceps measured by ultrasonography, and ECW/ICW ratio of the thigh assessed by S-BIS before (baseline) and after each set of RE (PostEx1, 2, and 3). The changes (Δ) in MT, EI, and ECW/ICW ratio were calculated as values of PostEx minus baseline values. The values of MT, EI, and ECW/ICW ratio at PostEx3 were significantly higher than baseline (effect size: MT, 1.11; EI, 0.47; and ECW/ICW ratio, 0.45). In addition, ΔMT was significantly and moderately correlated with ΔECW/ICW ratio (r = 0.61). Integrated data showed weak but significant correlation between ΔEI and ΔECW/ICW ratio as well (r = 0.31). The present results suggest multiple sets of exhaustive knee extension RE induce the acute increase of EI and ECW/ICW ratio as well as MT. The acute increase of muscle size after exercise can be at least partly explained by relative ECW increase.

Twenty-Four Months' Resistance and Endurance Training Improves Muscle Size and Physical Functions but Not Muscle Quality in Older Adults Requiring Long-Term Care.

To assess the effects of 24 months training on muscle quality, size, strength, and gait abilities in older adults who need long-term care. Non-randomized controlled trial Setting: Kawai Rehabilitation Center and Kajinoki Medical Clinic. Ten older participants who needed long-term care (age, 76.7 ± 5.6 years) were participated as training group (Tr-group) and 10 older men and women who did not require long-term care (age, 72.9 ± 6.6 years) comprised the control group (Cont-group). Tr-group performed resistive and endurance exercises once or twice a week for 24 months. Using ultrasound images, echo intensity (EI) and muscle thickness were measured in the rectus femoris and biceps femoris as an index of muscle quality and size. Physical performance was measured before and after the training; performance parameters included knee extension peak torque, 5-m normal and maximal walk test, sit-to-stand and timed up and go test. After the training, there was no change in EI, while BF thickness was increased (pre; 1.82 ± 0.29 cm, 24 months; 2.14 ± 0.23 cm, p < 0.05) in Tr-group. Walk-related performances were improved after the training in Tr-group (i.e. 5-m walk test and timed up and go test). The percent change of knee extension peak torque explained the percent change of EI in the rectus femoris (regression coefficient = 1.24, R = 0.91, adjusted R2 = 0.82, p < 0.001). Twenty-four months' training induced muscle hypertrophy and improved physical functions. Increased muscle quality in the rectus femoris could be a key to improved knee extension peak torque, with the potential to eventually reduce the need for long-term care in older individuals.

The effects of flexibility training on exercise-induced muscle damage in young men with limited hamstrings flexibility.

Adaptations to 6weeks of supervised hamstring stretching training and its potential impact on symptoms of eccentric exercise-induced muscle damage (EIMD) were studied in 10 young, untrained men with limited hamstrings flexibility. Participants performed unilateral flexibility training (experimental leg; EL) on an isokinetic dynamometer, while the contralateral limb acted as control (CL). Hip range of motion (ROM), passive, isometric, and concentric torques, active optimum angle, and biceps femoris and semitendinosus muscle thickness and ultrasound echo intensity were assessed both before and after the training. Additionally, muscle soreness was assessed before and after an acute eccentric exercise bout in both legs (EL and CL) at post-training only. Hip ROM increased (P<.001) only in EL after the training (EL=10.6° vs CL=1.6°), but no changes (P>.05) in other criterion measurements were observed. After a bout of eccentric exercise at the end of the program, isometric and dynamic peak torques and muscle soreness ratings were significantly altered at all time points equally in EL and CL. Also, active optimum angle was reduced immediately, 48 and 72hours post-exercise, and hip ROM was reduced at 48 and 72hours equally in EL and CL. Finally, biceps femoris muscle thickness was significantly increased at all time points, and semitendinosus thickness and echo intensity significantly increased at 72hours, with no significant differences between legs. The stretching training protocol significantly increased hip ROM; however, it did not induce a protective effect on EIMD in men with tight hamstrings.

Muscle compression improves reliability of ultrasound echo intensity.

Muscle echo intensity has been shown to correlate with disease status in muscle disorders, including Duchenne muscular dystrophy (DMD). We report the effect of sonographer-applied load on measurements of muscle echo intensity. Quadriceps ultrasound scans were performed on 22 healthy boys and 16 boys with DMD between the ages of 2.2 and 15.3 years. Transducer contact force was increased linearly from 1.5 to 10 N, and echo intensity was measured throughout. Echo intensity increased linearly with strain at a rate of 42 (95% confidence interval [CI]: 21-63) and 74 (95% CI: 49-98) in the healthy and DMD populations, respectively. Echo intensity reliability was moderate at low strain (intraclass correlation coefficient [ICC] = 0.82) and was improved at high strain (ICC = 0.92). Sonographer-applied load introduces error in measurements of echo intensity, but it can be minimized by measuring echo intensity at near-maximal levels of compression. Muscle Nerve 57: 423-429, 2018.

Test-retest reliability of echo intensity parameters in healthy Achilles tendons using a semi-automatic tracing procedure.

To evaluate the test-retest reliability of the ultrasound echo intensity parameters on healthy Achilles tendon using a semi-automatic tracing procedure. Eighteen healthy volunteers participated. B-mode images were acquired in the transverse plane (mid-tendon; insertion) and used to analyze tendon echogenicity. Grayscale distribution of the pixels within the selected ROIs was represented as a histogram. Descriptive statistics of the grayscale distribution (mean, variance, skewness, kurtosis, and entropy) and parameters from the co-occurrence matrix (contrast, energy, and homogeneity) were calculated. Reliability of echo intensity parameters of the mid-Achilles tendon ranged from high to very high with an ICC2.k of 0.94 for echogenicity, 0.87 for variance, 0.80 for skewness, 0.72 for kurtosis, 0.89 for entropy, 0.90 for contrast, 0.91 for energy, and 0.93 for homogeneity, while for tendon insertion they ranged from moderate to high with an ICC2.k of 0.74 for echogenicity, 0.88 for variance, 0.75 for skewness, 0.55 for kurtosis, 0.87 for entropy, 0.70 for contrast, 0.77 for energy, and 0.56 for homogeneity. Ultrasound echo intensity is a reliable technique to characterize the internal structure of the Achilles tendon.

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

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