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Background Several studies in adult hips have revealed the role of the gluteus medius (Gmed) and gluteus minimus (Gmin) muscles in maintaining the stability and centripetal force of the hip joint. Hip centripetality in developmental dysplasia of the hip (DDH) patients contributes to subsequent healthy hip development later in life. The purpose of this study is to investigate the relationship between Gmed and Gmin volume and centripetality of the hip in infant DDH patients. Methods We retrospectively enrolled 41 unilateral DDH patients (4 males, 37 females) who were treated by closed reduction from 2006 to 2016 and underwent magnetic resonance imaging at around 2 years old. Gmed, and Gmin volume was measured in magnetic resonance imaging. We defined both Gmin and Gmed together as hip abductor gluteus muscles (GMs; Gmed + Gmin). The muscle volume ratio of the affected side was calculated by dividing the GMs volume of the affected side by the contralateral side. Relationships between center-head distance discrepancy (CHDD) at 2 years old, and at 4–6 years old and GMs volume ratio were investigated by Pearson's correlation coefficient within the same patients. Results Mean age of closed reduction was 0.8 years old and mean age at MRI was 2.2 years old with a mean follow-up period of 3.7 years. Mean GMs volume in the affected side, contralateral side, and muscle volume ratio were 25.3 cm3, 27.0 cm3, and 0.94, respectively. GMs volumes were significantly higher in the contralateral side (p Conclusion GMs volume at 2 years old was found to be associated with later hip afferents. Promoting the healthy development of GMs by properly maintaining the infant's natural hip movement is important for the healthy hip development. Level of Evidence Level III.

After total or subtotal maxillectomy, reconstruction using a free rectus abdominis myocutaneous (RAMC) flap is a fundamental and useful option. The purpose of the present study was to clarify the degree of flap volume change and volume distribution change with time after total or subtotal maxillectomy and free RAMC flap reconstruction and to examine the factors affecting the results.A total of 20 patients who underwent total or subtotal maxillectomy with free RAMC flap reconstruction were examined, and the flap volume change rate (volume at final evaluation [POD 181-360] / volume at initial evaluation [POD 5-30]) was investigated using the results of imaging tests. Moreover, the flap was divided into four blocks (A-D) in the cranio-caudal direction, and the volume change of each block was individually analyzed.The overall volume change rate of fat/muscle/total was 0.84 ± 0.21/0.36 ± 0.08/0.67 ± 0.15, at the mean follow-up period of 309±35 days after the operation. The multiple regression analysis revealed that weight loss (for fat), postoperative RT (for fat and muscle), and young age (for muscle) were independently associated with flap volume loss. The results also indicated that the fat volume was stable, whereas the muscle volume decreased to40% over time, assuming there were no influencing factors. Regarding flap volume distribution change, the fat volume tended to gather toward the central-cranial direction, while the muscle volume gathered toward the cranial direction, and total flap volume gathered toward the central direction.

The purpose of this study was to clarify sequential volumetric changes of anterolateral thigh (ALT) flaps transferred to head and neck lesions.We retrospectively analyzed volumetric changes in fat and muscle of 22 ALT flaps. We assessed "true" flap volume using the water-displacement method intraoperatively. Postoperative flap volume was assessed using three-dimensional volume-calculating software.The average duration until the entire flap volume decreased to its minimal size was 8.7 months. After 8.7 months, entire flap volume decreased to 47.4% of its initial intraoperative volume. The fat volume decreased to 62.5%, and the muscle volume decreased to 30.2%. The rate of muscle volume decrease was significantly larger than that of fat volume decrease (p0.005). The only significant factor which affected entire flap volume decrease was the recipient site where the ALT flap was transferred (oral and pharyngeal lesions) (p=0.001), and the factor that affected fat volume decrease was postoperative body-weight loss (p=0.046).To minimize the influence of postoperative ALT flap volume decrease, an ALT flap should mainly comprise fatty tissue, and its size should be 1.6-times larger (100/62.5) than the ideal volume intraoperatively. Maintaining the body weight is crucial to avoid ALT flap volume decrease.

The quantity and quality of spinal muscles in patients with degenerative spinal diseases and various backgrounds such as age, gender, or race is unclear. We quantitatively evaluated the cross-sectional area (CSA) and fatty degeneration of the muscles around the spine, using magnetic resonance imaging (MRI) in patients with degenerative spinal disease, and studied the effects of age, gender, and race in multicenter retrospective study.The subjects were Caucasian and Asian patients with degenerative lumbar disease who underwent L4-5 single level spinal fusion surgery at centers in the United States and Japan. Using preoperative axial T2 MRI at the L4-5 disc level, the cross-sectional areas of the psoas and paraspinal muscles were measured. Fat infiltration was measured using the threshold method, and percent fat area (%FA) was calculated for each muscle. The muscle/disc area ratio (MDAR) was used to control for size differences per patient. T-test, Pearson's correlation coefficient, partial correlation, and multiple linear regression were used for statistical analysis.In total, 140 patients (53 men; 87 women; mean age, 69.2 years) were analyzed. Age was similar in Caucasians (n = 64) and Asians (n = 76). MDARs were larger in Caucasians for paraspinal and psoas muscles (p 0.005). Percent FA of psoas was similar in Caucasians and Asians, but greater in the paraspinal muscles of Asians (p 0.05). After controlling for race and gender, age was correlated negatively with MDAR (p 0.001) and positively with %FA (p 0.001). In the multiple linear regression analysis, age, gender, and race were independently affected by MDAR and %FA.Lumbar muscle mass and quality were affected by age, gender, and race, independently, in patients with degenerative lumbar disease.

This study aimed to determine the prognostic significance of low muscle volume (LMV) Bioelectrical Impedance Analysis (BIA), defined skeletal muscle index (SMI, Kg/mA prospective study of 122 patients diagnosed with OC [median age 65 yr, 104 male, 65 neoadjuvant therapy] who underwent preoperative BIA (Maltron Bioscan 920). Primary outcome measure was Overall Survival (OS).LMV was identified in 11 (9.0%) of patients, which was associated with low lean muscle mass (27.3 vs. 31.1 kg, p = 0.012), low body fat (8.8 vs.19.3 kg, p 0.001), and greater total body water (72.2 vs. 62.2%, p = 0.001), and more openclose laparotomies (36.4 vs. 8.1%, p = 0.012). Median and 5-year OS was 16 months and 18.2% in LMV patients, compared with 51 months and 52.4% in non-sarcopenic patients (p = 0.002). On multivariable analysis of pre-operative variables, only LMV (HR 2.75; 95% CI 1.33-5.66, p = 0.006) was associated with OS.BIA is an important prognostic indicator in OC and focused pre-habilitation consequently has strong potential.

Because endovascular abdominal aortic repair (EVAR) lowers the lumbar arterial blood flow, we hypothesized that the volume of the psoas muscle decreases after surgery. When internal iliac artery (IIA) embolization is performed, the lumbar arterial blood flow further decreases; therefore, we also hypothesized that the decrease in the volume of the psoas muscle becomes more significant. This study was performed to assess the volume change in the psoas muscle after EVAR.Fifty-three consecutive patients who underwent EVAR from January 2016 to December 2016 were included. The psoas muscle volume was measured by preoperative and postoperative computed tomography (CT). Postoperative CT scans were performed 6-12 months after EVAR. Axial CT images with a 2-mm slice thickness were used to measure the psoas muscle volume. Data were transferred to a 3-dimensional workstation, and the psoas muscle volume was measured.In the EVAR group, the volume of the psoas muscle decreased by an average of 5.8 mL (4.6%) from 114.8 ± 32.0 mL preoperatively to 109.0 ± 30.3 mL postoperatively (P 0.01). There was a significant difference in the change in the psoas muscle volume between patients with and without IIA embolization (embolization group: preoperative 118.1 ± 31.0 mL, postoperative 107.5 ± 29.2 mL, mean volume change rate -8.8%; nonembolization group: preoperative 114.0 ± 32.3 mL, postoperative 109.4 ± 30.7 mL, mean volume change rate -3.6%; P 0.05).The psoas muscle volume is reduced with EVAR. Moreover, when the IIA is embolized, the psoas muscle volume is further reduced.

Measures of skeletal muscle abnormalities are rapidly emerging as independent predictors of outcomes after liver transplantation (LT). We describe a simple, novel assessment of myosteatosis acquired prior to liver transplantation using Magnetic Resonance Imaging (MRI) derived fat fraction.A retrospective longitudinal cohort study included clinical and biochemical data from patients who underwent liver transplantation at our institution between Feb 2008 and Aug 2014. Patients transplanted for a diagnosis of hepatocellular carcinoma were excluded from the study. The fat fraction of erector spinae muscles was estimated using MRI at the level where muscle volume was highest, with myosteatosis defined at a cut-off value of 0.8.180 patients were included. At baseline, those with myosteatosis were, on average, older, more likely to be female, and more likely to receive a multi-organ transplant (p 0.05). Patients with pre-transplant myosteatosis, as delineated by MRI derived fat fraction, also had increased length of hospital stay.This preliminary study suggests myosteatosis, as measured by fat fraction on MRI prior to LT, may be associated with increased graft loss and mortality after transplant.

We investigated the usefulness of segmental multifrequency bioelectrical impedance analyses (MBIA) for assessing muscle involvement in Duchenne muscular dystrophy (DMD) patients. Bioelectrical impedance data of the upper arm, thigh, and lower leg were obtained from 29 boys with DMD (ages 2–17 years old; mean 10.8 ± 3.9 years) at three institutions along with 41 healthy controls (ages 3–16; mean 9.8 ± 3.5 years). Then the muscle density index (MDI: 1- Z250/Z5) was calculated using segmental MBIA and compared between groups. The MDI was lower in boys with DMD, relative to controls, with older DMD patients exhibiting a significant decrease in MDI. The MDI of patient thighs was significantly correlated with the percent muscle volume index (%MVI), as measured using computed tomography (r = 0.79). MDI values for the upper arm, thigh, and lower leg were all significantly correlated with the Brooke and the Vignos scales, respectively, with correlation coefficients of 0.56–0.77. Finally, MDI was significantly greater in the glucocorticoid-treated group, relative to the untreated group in all regions. Taken together, these data show that segmental MBIA is feasible for evaluating muscle involvement and might serve as an outcome measure in DMD.

Bioelectrical impedance spectroscopy (BIS) can assess intracellular water (ICW) and total water (TW) in limbs. This study aimed to examine whether BIS can explain a part of the inter-individual variation of the muscle size-strength relationship in older adults. We analyzed the data of 79 participants aged 64-86 years. The maximal voluntary isometric torques of dorsiflexion and plantar flexion on the right side were measured. The anterior and posterior muscle thickness (MT) in the right lower leg was assessed using ultrasonography. The length of the right lower leg (L) was measured, and the ICW-to-TW ratio (ICW/TW) in the right lower leg was obtained using BIS. The MT was multiplied by L to represent an index of muscle volume (MV). Correlation and stepwise regression analyses were performed. The anterior and posterior MT × L significantly and positively correlated with the muscle torque of dorsiflexion and plantar flexion (r = 0.710 and 0.649, respectively, P 0.001). In the stepwise regression analyses, ICW/TW was selected as a significant predictor of muscle torque independent of MT × L (P 0.05) for both dorsiflexion and plantar flexion. Electrical parameters of BIS (membrane capacitance, characteristics frequency, and phase angle) in the lower leg also significantly correlated with muscle torques. In addition, the skeletal muscle mass index (appendicular lean mass/height

The objective of this study was to identify parameters for the evaluation of pork belly quality (composition) and quantity (volume) and to develop regression equations that predict properties of whole pork belly. Through an image analysis of 648 bellies, newly characterized pork belly parameters were developed for evaluating pork belly quality and quantity. Importantly, the estimated muscle volume showed high positive correlation with the whole belly volume and the whole belly muscle percentage (r=0.458, and 0.654, respectively). Section 7 was identified as the best section for the evaluation of pork belly based on the muscle area in every vertebra. A stepwise regression showed that cutaneous trunci muscle (CTM) had an r2 of 0.624 in the model, and supplementation with the other muscles yielded an r2 of 0.784. Therefore, we propose that a prediction equation could be developed for a certain area in the belly for the evaluation of pork belly quantity and quality. The results could be applied to select breeding stock using techniques such as ultrasound with the aim of producing hogs with large as well as lean bellies.

BackgroundDeficits in muscle volume may be a significant contributor to physical disability in young people with cerebral palsy. However, 3D measurements of muscle volume using MRI or 3D ultrasound may be difficult to make routinely in the clinic. We wished to establish whether accurate estimates of muscle volume could be made from a combination of anatomical cross-sectional area and length measurements in samples of typically developing young people and young people with bilateral cerebral palsy.MethodsLower limb MRI scans were obtained from the lower limbs of 21 individuals with cerebral palsy (14.7 ± 3 years, 17 male) and 23 typically developing individuals (16.8 ± 3.3 years, 16 male). The volume, length and anatomical cross-sectional area were estimated from six muscles of the left lower limb.FindingsAnalysis of Covariance demonstrated that the relationship between the length*cross-sectional area and volume was not significantly different depending on the subject group. Linear regression analysis demonstrated that the product of anatomical cross-sectional area and length bore a strong and significant relationship to the measured muscle volume (R2 values between 0.955 and 0.988) with low standard error of the estimates of 4.8 to 8.9%.InterpretationThis study demonstrates that muscle volume may be estimated accurately in typically developing individuals and individuals with cerebral palsy by a combination of anatomical cross-sectional area and muscle length. 2D ultrasound may be a convenient method of making these measurements routinely in the clinic.

Diagnostic imaging modalities, like computed tomography (CT) and magnetic resonance imaging (MRI), can be used to assess in vivo muscle quality. Quantitative assessment using these techniques is time-intensive and costly due in part to extensive post-processing needs. The purpose of this study was to identify whether a subset of slices on CT and MRI would yield comparable results to the full number of slices for a measure of muscle quality (muscle deterioration ratio = fat volume/muscle volume) in the foot intrinsic muscles of people with diabetes and peripheral neuropathy. CT (0.6 mm slice thickness) and MRI (3.5 mm slice thickness) scans were obtained using previously described methods. The total number of slices acquired during the scan was compared to several conditions using a portion of slices. Bland-Altman plots and Lin’s concordance correlation coefficient were used to test agreement. Any condition using at least three slices yielded substantial to almost perfect agreement with the total number of slices on both CT and MRI (Range of Lin’s concordance correlation coefficient: 0.947–0.999). Using a single slice in the middle of the region of interest demonstrated poor to moderate agreement with the total number of slices. The findings of this study suggest that using a limited number of slices to quantify muscle deterioration ratio on CT or MRI is a viable way to balance the combined need for measurement accuracy with feasibility in research and clinical settings.

Longus capitis and colli are proposed to play a role in stabilising the cervical spine, targeted in clinical and research practice with cranio-cervical flexion. However, it is not clear if these muscles are anatomically or biomechanically suited to a stabilising role.To describe the fascicular morphology of the longus capitis and colli, and estimate their peak force generating capabilities across the individual cervical motion segments.Biomechanical force modelling based on anatomical data.Three-part design including cadaveric dissection (n = 7), in vivo MRI muscle volume calculation from serial slices in young healthy volunteers (n = 6), and biomechanical modelling of the peak force generating capacities based on computed tomography scans of the head and neck.Longus capitis and colli are small muscles spanning multiple cervical motion segments. Bilateral peak flexion torque estimates were higher in the upper cervical spine (0.5 Nm), and unlikely to affect motion below the level of C5 (0.2 Nm). Peak shear estimates were negligible (20 N), while peak compression estimates were small (80 N).These data highlight the complex anatomy and small force capacity of longus capitis and colli, and have implications for their function. In particular, the small peak compression forces indicate that these muscles have a limited capacity to contribute to cervical stability via traditional mechanisms. This implies that the mechanism(s) by which cranio-cervical flexion exercises produce clinical benefits is worth exploring further.

In total hip arthroplasty (THA) surgery, hip muscle preservation is important in strengthening the stability of the hip and improving the activities of the patient. However, whether the type of femoral stem affects the recovery of the hip muscles remains unknown. The aim of this study was to compare the postoperative hip muscle recovery among femoral stem varieties after THA.The computed tomography (CT) images of 44 patients (44 hips) who underwent THA using an anterolateral approach were reviewed. Twenty-two patients received a fit-and-fill (FF) stem and 22 received the tapered-wedge (TW) stem. The volumes of the gluteus maximus (GMA), gluteus medius (GME), and obturator internus (OI) were measured on three-dimensional models reconstructed using preoperative and 6-month postoperative CT images. Relationships between muscle volume changes and factors including the femoral stem length were evaluated.The GMA and GME volumes increased postoperatively by 8.2% and 8.3%, respectively, in the FF stem group and 7% and 6%, respectively, in the TW stem group, with no group differences. In contrast, the OI volume decreased postoperatively by 17.8% in the FF group and was preserved in TW group (p 0.001). Moreover, OI volume was decreased in 19 patients (86%) in the FF group and in 11 patients (50%) in the TW group (p = 0.01). The normalized stem length was significantly associated with the postoperative change in OI volume (r = -0.45, p = 0.002).The TW stem showed a significant advantage over the FF stem in terms of OI preservation. Surgeons should pay close attention during surgery to avoid OI injury when using different femoral stem types. We suggest that a short and reduced lateral shoulder femoral stem is a better choice for the preservation of external rotation muscles.

Treatment/prevention of shoulder muscle strength imbalances are major therapeutic goals for children with obstetrical brachial plexus palsy. The study aims were to characterize muscle atrophy in children/adolescents with unilateral obstetrical brachial plexus palsy, to quantify the agonist-antagonist muscle volume balance and the association between muscle volume and strength.Eight boys and four girls (age=12.1, standard deviation=3.3) participated in this case-control study. Three-dimensional magnetic resonance images of both shoulders were acquired. The unimpaired shoulder served as a reference. Volumes of deltoid, pectoralis major, supraspinatus, infraspinatus, teres major, subscapularis were calculated based on 3D models, derived through image segmentation. Maximal isometric torques were collected in six directions.All the major muscles studied were significantly atrophied. The teres major demonstrated the biggest difference in atrophy between groups (51 percentage points), the pectoralis major was the least atrophied (23 percentage points). The muscle volume distribution was significantly different between shoulders. Muscle volume could predict maximal voluntary isometric torques, but the regression coefficients were weaker on the impaired side (72% to 91% of the strength could be predicted in the uninvolved side and 24% to 90% in the involved side and external rotation strength could not be predicted).This study demonstrates muscle atrophy varied across all the main shoulder muscles of the glenohumeral joint, leading to significant muscle volume imbalances. The weaker coefficients of determination on the impaired side suggest that other variables may contribute to the loss of strength in addition to atrophy.

Background Thigh lean muscle and intramuscular fat have been implicated in the impairment of physical function observed in people with knee osteoarthritis. We investigated the relationships of quadriceps and hamstrings intramuscular fat fraction and lean muscle volume with muscle power and strength, controlling for neuromuscular activation, and physical performance in women with knee OA. Methods Women (n = 20) 55 years or older with symptomatic, radiographic knee osteoarthritis underwent a 3.0T magnetic resonance imaging scan of the thigh of their most symptomatic knee. Axial fat-separated images were analyzed using software to quantify intramuscular fat and lean muscle volumes of the quadriceps and hamstrings. To quantify strength and power of the knee extensors and flexors, participants performed maximum voluntary isometric contraction and isotonic knee extensions and flexions, respectively. Electromyography of the quadriceps and hamstrings was measured. Participants also completed five physical performance tests. Findings Quadriceps and hamstrings lean muscle volumes were related to isotonic knee extensor (B = 0.624; p = 0.017) and flexor (B = 1.518; p = 0.032) power, but not knee extensor (B = 0.001; p = 0.615) or flexor (B = 0.001; p = 0.564) isometric strength. Intramuscular fat fractions were not related to isotonic knee extensor or flexor power, nor isometric strength. No relationships were found between intramuscular fat or lean muscle volume and physical performance. Interpretation Muscle power may be more sensitive than strength to lean muscle mass in women with knee osteoarthritis. Thigh lean muscle mass, but neither intramuscular nor intermuscular fat, is related to knee extensor and flexor power in women with knee osteoarthritis.

The utility of quantitative muscle ultrasound as a marker of disease severity in Charcot-Marie-Tooth (CMT) disease subtypes was investigated.Muscle ultrasound was prospectively performed on 252 individual muscles from 21 CMT patients (9 CMT1A, 8 CMTX1, 4 CMT2A) and compared to 120 muscles from 10 age and gender-matched controls. Muscle ultrasound recorded echogenicity and thickness in representative muscles including first dorsal interosseus (FDI) and tibialis anterior (TA).Muscle volume of FDI and thickness of TA correlated with MRC strength. Muscle echogenicity was significantly increased in FDI (65.05 vs 47.09; p0.0001) and TA (89.45 vs 66.30; p0.0001) of CMT patients. In TA, there was significantly higher muscle thickness (23 vs 18 vs 16mm; p0.0001) and lower muscle echogenicity (80 vs 95 vs 108; p0.0001) in CMT1A compared to CMTX1 and CMT2A. This corresponded to disease severity based on muscle strength (MRC grading CMT1A vs CMTX1 vs CMT2A: 59 vs 48 vs 44; p=0.002).In CMT, quantitative muscle ultrasound of FDI and TA is a useful marker of disease severity.The current findings suggest that quantitative muscle ultrasound has potential as a surrogate marker of disease progression in future interventional trials in CMT.

Made available in DSpace on 2018-11-26T17:10:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 We evaluated lateral pterygoid muscle volume in closed and open mouth positions in association with anterior disc displacement, effusion and abnormal articular disc shape from three-dimensional reformations of MRI. A total of 24 MRI of a sample (15 females, 9 males) aged 19-64 years (37.2 years +/- 11.4) were assessed. Segmentation and volumetric assessment of the total, upper and lower heads of the lateral pterygoid muscle were performed using free software. The upper head of the lateral pterygoid muscle had a smaller volume than the lower head at both sides, in the closed- and open-mouth positions. In the open-mouth position, individuals with a subdivided upper head, where one component was inserted in the articular disc and another in the mandibular head, displayed a significantly larger volume of the upper head compared to individuals who had a single attachment to the articular disc (p = 0.0130). The lateral pterygoid muscle has different volumes in the closed-and open-mouth positions. Gender affected muscle volume, specifically the upper head component. Insertion type in the upper head also seemed to affect muscle volume. (C) 2016 Elsevier GmbH. All rights reserved. Univ Sao Paulo City, Dept Orthodont, Sao Paulo, SP, Brazil Sao Paulo State Univ, Sao Jose dos Campos Dent Sch, Dept Diag & Surg, Sao Jose Dos Campos, SP, Brazil Univ Paulista, Dept Radiol, Campinas, SP, Brazil Sao Paulo State Univ, Sao Jose dos Campos Dent Sch, Dept Diag & Surg, Sao Jose Dos Campos, SP, Brazil

Background Deficits in muscle volume may be a significant contributor to physical disability in young people with cerebral palsy. However, 3D measurements of muscle volume using MRI or 3D ultrasound may be difficult to make routinely in the clinic. We wished to establish whether accurate estimates of muscle volume could be made from a combination of anatomical cross-sectional area and length measurements in samples of typically developing young people and young people with bilateral cerebral palsy. Methods Lower limb MRI scans were obtained from the lower limbs of 21 individuals with cerebral palsy(14.7 ± 3 years, 17 male) and 23 typically developing individuals (16.8 ± 3.3 years, 16 male). The volume, length and anatomical cross-sectional area were estimated from six muscles of the left lower limb. Findings Analysis of Covariance demonstrated that the relationship between the length*cross-sectional area and volume was not significantly different depending on the subject group. Linear regression analysis demonstrated that the product of anatomical cross-sectional area and length bore a strong and significant relationship to the measured muscle volume (R2 values between 0.955 and 0.988) with low standard error of the estimates of 4.8 to 8.9%. Interpretation This study demonstrates that muscle volume may be estimated accurately in typically developing individuals and individuals with cerebral palsy by a combination of anatomical cross-sectional area and muscle length. 2D ultrasound may be a convenient method of making these measurements routinely in the clinic.

Objective To study motor unit activity in the medio-lateral extension of the masseter using an adapted scanning EMG technique that allows studying the territories of multiple motor units (MUs) in one scan. Methods We studied the m. masseter of 10 healthy volunteers in whom two scans were performed. A monopolar scanning needle and two pairs of fine-wire electrodes were inserted into the belly of the muscle. The signals of the fine wire electrodes were decomposed into the contribution of single MUs and used as a trigger for the scanning needle. In this manner multiple MU territory scans were obtained simultaneously. Results We determined 161 MU territories. The maximum number of territories obtained in one scan was 15. The median territory size was 4.0 mm. Larger and smaller MU territories were found throughout the muscle. Conclusions The presented technique showed its feasibility in obtaining multiple MU territories in one scan. MUs were active throughout the depth of the muscle. Significance The distribution of electrical and anatomical size of MUs substantiates the heterogeneous distribution of MUs throughout the muscle volume. This distributed activity may be of functional significance for the stabilization of the muscle during force generation.

Amino acid metabolites, including branched-chain amino acids (BCAA) and tyrosine (Tyr), affect glucose metabolism. The effects of BCAA on insulin resistance in patients with diabetes seem to conflict with mechanisms determined in animal models and cultured cells. The aim of this study was to clarify the controversy surrounding the effects of BCAA by investigating the physiological effects of BCAA and Tyr on glucose metabolism in healthy community dwellers.We investigated associations among BCAA and Tyr and metabolic parameters in 78 residents (median age, 52 y) of Mie, Japan, who did not have prediabetes, diabetes, or a body mass index30 kg/m(2).Muscle volume, serum BCAA, and Tyr levels were higher in men than in women (n = 32 and 46, respectively; all P 0.0001). Stepwise multiple regression analysis associated BCAA positively with muscle volume (regression coefficient/t/p/95% confidence interval, 281.8/3.7/0.0004/129.7-433.8), fasting blood glucose (FBG; 12699.4/3.22/0.0020/4830.9-20567.8), fasting immunoreactive insulin (IRI; 8505.1/2.75/0.0078/2322.5-14687.6), and homeostasis model assessment of β-cell function (HOMA-β; 893.6/2.58/0.0122/201.8-1585.5), and negatively with the HOMA-insulin resistance (HOMA-IR; -9294.1/-2.89/0.0052/-15711.0 to -2877.1). Tyr positively correlated with fasting IRI (26/2.77/0.0072/7.3-44.7).Insulin sensitivity and muscle volume are positively associated with BCAA in individuals without diabetes. In turn, BCAA correlate with increased FBG and fasting IRI levels. Tyr correlated with fasting IRI, but not with insulin sensitivity.

Introduction: Muscle is strongly related to cortical bone architecture in children; however, the relationship between muscle volume and trabecular bone architecture is poorly studied. The aim of this study was to determine if muscle volume is related to trabecular bone architecture in children and if the relationship is different than the relationship between muscle volume and cortical bone architecture. Materials and methods: Forty typically developing children (20 boys and 20 girls; 6 to 12. y) were included in the study. Measures of trabecular bone architecture [i.e., apparent trabecular bone volume to total volume (appBV/TV), trabecular number (appTb.N), trabecular thickness (appTb.Th) and trabecular separation (appTb.Sp)] in the distal femur, cortical bone architecture [cortical volume, total volume, section modulus (Z) and polar moment of inertia (J)] in the midfemur, muscle volume in the midthigh and femur length were assessed using magnetic resonance imaging. Total physical activity and moderate-to-vigorous physical activity were assessed using an accelerometer-based activity monitor worn around the waist for four days. Calcium intake was assessed using diet records. Relationships among the measures were tested using multiple linear regression analysis. Results: Muscle volume was moderately-to-strongly related to measures of trabecular bone architecture [appBV/TV (r=0.81), appTb.N (r=0.53), appTb.Th (r=0.67), appTb.Sp (r=-0.71); all p0.05). Because muscle volume and femur length were strongly related (r=0.91, p2.77). When muscle volume/femur length2.77 was included in a regression model with femur length, sex, physical activity and calcium intake, muscle volume/femur length2.77 was a significant predictor of appBV/TV, appTb.Th and appTb.Sp (partial r=0.44 to 0.49, p

Background: Late-onset Pompe disease (LOPD) is a metabolic myopathy caused by mutations in GAA and characterized by proximal muscle weakness and respiratory insufficiency. There is evidence from clinical studies that enzyme replacement therapy (ERT) with human recombinant alpha-glucosidase improves motor performance and respiratory function in LOPD. Objective: We analyzed quantitative muscle MRI data of lower limbs to evaluate the effects of long-term ERT on muscle parameters. Methods: Three symptomatic LOPD patients who received ERT for five years and four untreated presymptomatic LOPD patients were included in the study. T1-weighted MRI images were used to determine volumes of thigh and lower leg muscles. In addition, mean gray values of eight individual thigh muscles were calculated to assess the degree of lipomatous muscle alterations. Results: We detected a decrease in thigh muscle volume of 6.7% (p

Pompe disease is a rare, inherited metabolic myopathy characterized by progressive weakness of the proximal limb and respiratory muscles. We report the findings from four patients with late-onset Pompe disease treated with α-glucosidase (Myozyme) for 2 ( n = 2) and 6 ( n = 2) years, and monitored with isokinetic dynamometry, 6-minute walking test (6MWT), and vital capacity. Patients were evaluated after 6, 12, 24, 36, 48, 60, and 72 months. In two patients, muscle size estimated by MRI and DXA scanning was also performed prior to and following 6 months of treatment. After 2 years of α-glucosidase treatment, maximal isokinetic muscle strength increased by 11% (0%–50%) [median (range)] and 6MWT improved by 18% (2%–40%). In the two patients treated for 6 years, the increase in muscle strength stabilized at 40% and 6MWT stabilized at 32%. The improvements primarily occurred during the first 6 months of treatment. Interestingly, the weakest muscle groups seemed to benefit more than those less affected, and greater improvements occurred for flexor muscles compared to extensor muscles. Vital capacity did not improve on treatment.

Aim: Muscle weakness is a feature of individuals with spastic cerebral palsy (SCP) but there are few reports in the literature of muscle volume in this group. This study compares muscle volumes in adolescents and young adults with SCP with those of their typically developing (TD) peers. Design: Measurements of the volumes of nine major lower limb muscles in 19 independently ambulant subjects with SCP (mean age 14.2 years (sd 2.7), 11 male, GMFCS I ( n = 5); GMFCS II ( n = 14)), 19 TD subjects (mean age 16.5 years (sd 3.0), 11 male) were made using magnetic resonance imaging. Results: Lower limb muscles were smaller in the SCP group ( p ⩽ 0.023 in all muscles) than the TD group with the exception of the vastii (lateralis + intermedius; p = 0.868) and gluteus maximus ( p = 0.056). Average muscle volume deficit was 27.9%. Muscle volume deficits were significantly greater for distal muscles than proximal muscles ( p Conclusions: Reduced muscle size in adolescence and the natural history of sarcopenia in adulthood may contribute to the early loss of mobility of adults with SCP.

The present study investigated the validity of a simplified muscle volume assessment that uses only the maximum anatomical cross-sectional area (ACSAmax), the muscle length (LM) and a muscle-specific shape factor for muscle volume calculation (Albracht et al., 2008, J Biomech 41, 2211-2218). The validation on the example of the triceps surae (TS) muscles was conducted in two steps. First LM, ACSAmax, muscle volume and shape factor were calculated from magnet resonance image muscle reconstructions of the soleus (SO), gastrocnemius medialis (GM) and lateralis (GL) of a group of untrained individuals (n=13), endurance (n=9) and strength trained (n=10) athletes. Though there were significant differences in the muscle dimensions, the shape factors were similar across groups and were in average 0.497 ± 0.026, 0.596 ± 0.030, and 0.556 ± 0.041 for the SO, GM and GL respectively. In a second step, the shape factors were applied to an independent recreationally active group (n=21) to compare the muscle volume assessed by the simplified method to the results from whole muscle reconstructions. There were no significant differences between the volumes assessed by the two methods. In conclusion, assessing TS muscle volume on the basis of the reported shape factors is valid across populations and the root mean square differences to whole muscle reconstruction of 7.9%, 4.8% and 8.3% for SO, GM and GL show that the simplified method is sensitive enough to detect changes in muscle volume in the context of degeneration, atrophy or hypertrophy.

Muscle adaptations can be induced by high-resistance exercise. Despite being potentially more suitable for older adults, low-resistance exercise protocols have been less investigated. We compared the effects of high- and low-resistance training on muscle volume, muscle strength, and force-velocity characteristics. Fifty-six older adults were randomly assigned to 12 weeks of leg press and leg extension training at either HIGH (2×10-15 repetitions at 80% of one repetition maximum (1RM)), LOW (1×80-100 repetitions at 20% of 1RM), or LOW+ (1×60 repetitions at 20% of 1RM, followed by 1×10-20 repetitions at 40% of 1RM). All protocols ended with muscle failure. Leg press and leg extension of 1RM were measured at baseline and post intervention and before the first training session in weeks 5 and 9. At baseline and post intervention, muscle volume (MV) was measured by CT-scan. A Biodex dynamometer evaluated knee extensor static peak torque in different knee angles (PT(stat90°), PT(stat120°), PT(stat150°)), dynamic peak torque at different speeds (PT(dyn60°s)(-1), PT(dyn180°s)(-1), PT(dyn240°s)(-1)), and speed of movement at 20% (S20), 40% (S40), and 60% (S60) of PTstat90°. HIGH and LOW+ resulted in greater improvements in 1RM strength than LOW (p

Objective The objective of this study was to investigate differences in masseter metabolism by 31 P-Chemical Shift Imaging (CSI) in adult individuals with different vertical facial patterns. The clinical study should be supported by functional findings at the mRNA level after orthognathic surgery. Study Design Twenty-two male volunteers (mean age 24.6) were divided into a deep-bite (NL/ML 11.8 ± 2.3°) and open-bite group (NL/ML 34.1 ± 2.6°). Vertical jaw relationship, gonial angle, and masseter volume were defined and compared with the phosphate values obtained from the 31 P spectra. Student t test and regression analysis were used. Results Phosphocreatine related strongly to muscle volume ( P P P P P P Conclusions A difference in masseter muscle metabolism between long- and short-faced subjects was confirmed at rest position.

Aging is associated with the loss of muscle volume (MV) and force leading to difficulties with activities of daily living. However, the relationship between upper limb MV and joint strength has not been characterized for older adults. Quantifying this relationship may help our understanding of the functional declines of the upper limb that older adults experience. Our objective was to assess the relationship between upper limb MV and maximal isometric joint moment-generating capacity (IJM) in a single cohort of healthy older adults (age ≥ 65 years) for 6 major functional groups (32 muscles). MV was determined from MRI for 18 participants (75.1±4.3 years). IJM at the shoulder (abduction/adduction), elbow (flexion/extension), and wrist (flexion/extension) was measured. MV and IJM measurements were compared to previous reports for young adults (28.6±4.5 years). On average older adults had 16.5% less total upper limb MV compared to young adults. Additionally, older adult wrist extensors composed a significantly increased percentage of upper limb MV. Older adult IJM was reduced across all joints, with significant differences for shoulder abductors (p

Musculoskeletal computer models are often used to study muscle function in children with and without impaired mobility. Calculations of muscle forces depend in part on the assumed strength of each muscle, represented by the peak isometric force parameter, which is usually based on measurements obtained from cadavers of adult donors. The aim of the present study was twofold: first, to develop a method for scaling lower-limb peak isometric muscle forces in typically-developing children; and second, to determine the effect of this scaling method on model calculations of muscle forces obtained for normal gait. Muscle volumes were determined from magnetic resonance (MR) images obtained from ten children aged from 7 to 13yr. A new mass-length scaling law was developed based on the assumption that muscle volume and body mass are linearly related, which was confirmed by the obtained volume and body mass data. Two musculoskeletal models were developed for each subject: one in which peak isometric muscle forces were estimated using the mass-length scaling law; and another in which these parameters were determined directly from the MR-derived muscle volumes. Musculoskeletal modeling and quantitative gait analysis were then used to calculate lower-limb muscle forces in normal walking. The patterns of muscle forces predicted by the model with scaled peak isometric force values were similar to those predicted by the MR-based model, implying that assessments of muscle function obtained from these two methods are practically equivalent. These results support the use of mass-length scaling in the development of subject-specific musculoskeletal models of children.

This paper uses a Hill-type EMG-Driven model to estimate isometric quadriceps forces of 4 males subjects after a strength training period in an isokinetic device (Cybex-Norm), aiming for muscle hypertrophy. Before (PRE) and after (POS) training, quadriceps PCSAs were estimated from ultrasound measurements. Each individual followed a protocol of 10 s submaximal (20% and 60%MVC) knee extension isometric contractions. Knee torque and surface EMG from three superficial quadriceps components were synchronously collected. EMG signal from vastus intermedius was estimated from other muscles. After training, the subjects presented an increase of 14.3 ± 5.1% of the maximum isometric torque, while the gain of muscle volume was 6.0 ± 3.0%. RMS error between EMG-driven and dynamometer joint torques, for the best estimation condition, were: 20%MVC PRE= 10.8 ± 3.8%, POS = 11,0 ± 4.9%; 60%MVC PRE = 12.1 ± 3.2%, POS = 8.3 ± 2.5%. These results are analyzed under the viewpoint of modeling and experimental reliability.

The muscle torque per unit volume of the hamstrings on the injured and uninjured sides in patients with ACL reconstruction were compared with participants with no history of knee injury to examine whether a similar mechanism leading to quadriceps weakness exists in the hamstrings of these patients. The study population consisted of 18 and 52 patients ator=6 and 12 months after ACL reconstruction, respectively, and 35 healthy controls. The hamstring volume was measured on MRI. To identify the muscle torque per unit volume, the peak torque of knee flexion was divided by the hamstring volume. Most muscle torque per unit volume indexes were not significantly different between the patients ator=6 months (injured side: 0.133+/-0.03 Nm/cm(3), 60 degrees /s; 0.107+/-0.03 Nm/cm(3), 180 degrees /s; uninjured side: 0.139+/-0.02 Nm/cm(3), 60 degrees /s; 0.107+/-0.02 Nm/cm(3), 180 degrees /s) and controls (0.170+/-0.05 Nm/cm(3), 60 degrees /s; 0.121+/-0.05 Nm/cm(3), 180 degrees /s). However, the muscle torque per unit volume of patients at 12 months in both injured (0.118+/-0.03 Nm/cm(3), 60 degrees /s; 0.092+/-0.02 Nm/cm(3), 180 degrees /s) and uninjured sides (0.120+/-0.03 Nm/cm(3) at 60 degrees /s; 0.094+/-0.02 Nm/cm(3), 180 degrees /s) were significantly lower than those of controls (P0.01). We found no evidence of recruitment disorder in the hamstrings of the patients. The results of this study indicated that the mechanism of muscle weakness of the hamstrings after reconstruction was different from that of the quadriceps, although the precise mechanism remains to be determined.

The objective of this study was to determine the accuracy of an echographic method for measuring the change in leg muscle volume against the gold standard, magnetic resonance imaging (MRI). Leg muscle volume was measured using an echographic scanner, which consisted of two metallic rails on which a probe holder moved via an electric engine. Ten to 20 transverse muscle views were collected along the area scanned, and the muscle cross-sectional area (CSA, cm2) was measured on each of them. The integration of all the CSAs along the scanned area provided the muscle volume (cm3). Echographic results were compared with MRI data on 24 subjects undergoing 60 d of bed rest (8 control "Con," 8 with exercise countermeasures "Ex" and 8 with nutrition countermeasures "Nut"). The vastus intermedius (VI) and the vastus medialis (VM) volumes decreased significantly and similarly in both Con and Nut (VI, -17%; VM, -21%; p < 0.02). In the Ex group, the VI and VM did not change significantly. The correlation coefficient between the muscle volume change measured with the echographic and MRI methods was 0.78. The present study confirms that the echographic scanner is sufficiently accurate for assessing muscle volume changes and detects the effect of exercise countermeasures on muscle volume during long-term bed rest.

Muscle volume is an essential parameter in clinical evaluation and in biomechanical model development. Nevertheless, the difficulty in volumic muscle reconstruction from medical images is the noise they contain that limits the efficiency of image processing to automatically segment muscle. This study was conducted to explore hip muscle volume from CT-scan acquisition and to analyze the variability of muscle volume for a population of 98 subjects with age ranged from 21 to 94 years. To obtain three-dimensional muscle reconstruction, a method based on a deformation of a parametric specific object generated from a reduced number of muscle contours was used. A reproducibility study was conducted for muscle volume estimation. Coefficient of variation was found less than 8.9% and intraclass correlation coefficients were greater than 0.88. Results showed no significant difference between left and right muscles for this population. After adjustment to age and body mass index, hip muscle volumes were significantly different between men and women. This muscle volume reconstruction method allowed quantifying muscle volume distribution within a large population.

The purpose of the present study was to investigate whether it is possible to predict the individual muscle volumes within the triceps surae (TS) muscle group by means of easily measurable parameters based on a theoretical consideration. A further objective was to verify the use of the available literature data to assess the contribution of each muscle of the group to the entire TS volume or physiological cross-sectional-area (PCSA). Therefore, magnetic resonance images of the right calf of 13 male subjects were acquired and each muscle of the TS was reconstructed. Muscle length (l(m)), the maximum anatomical cross-sectional-area (ACSA(max)) and muscle volume were obtained from the 3D models. To assess the PCSA, fascicle length was determined by ultrasonography. In general, muscle volume can be expressed as a fraction of the product of ACSA(max) and l(m). The size of the fraction depends on muscle shape and its coefficient of variance among the examined population was considerable low (soleus 6%, gastrocnemius 4% and gastrocnemius lateralis 7%) in the present study. The product of ACSA(max) and l(m) was, therefore, suitable to assess muscle volume (root mean squares, RMS 4-7%). Further, the soleus, gastrocnemius medialis and gastrocnemius lateralis accounted on average for about 52+/-3%, 32+/-2% and 16+/-2% of the total TS volume and 62+/-5%, 26+/-3% and 12+/-2% of the entire TS PCSA, respectively. The coefficient of variance of the relative portions were 5-10% for muscle volume and 8-17% for the PCSA.

To evaluate the contamination of glycogen signal synthesized in skeletal muscle by that in the liver, long-term monitoring of over 7 h of in vivo [1- 13 C] glycogen synthesis/degradation at the right abdomen and left shoulder was achieved using a 3.0-T clinical MR system. 13 C MR spectra without localization were obtained from five healthy volunteers before and after oral administration of 85 g of d -glucose, including 10 g of 99% [1- 13 C] glucose. In all volunteers, the relative signal intensities at the abdomen to those at shoulder were about two- to fivefold, and those of time-course changes at the abdomen and shoulder were dissimilar. It is considered that the quantity of muscle-synthesized glycogen signal at the abdomen is less than that at the shoulder because of the lesser muscle volume at the abdomen, and it may be less affected for evaluating glycogen synthesis/degradation in the liver even without localization pulses.

The present study aimed to investigate the effect of resistance training on the volume of four muscle groups and/or 17 individual muscles of the human lower limb during 20 days of 6 ∘ head-down tilt bed rest. Twelve healthy men were divided into two groups: the resistance training group: BR-Tr ( n = 6 ) and the control group: BR-Cont ( n = 6 ) . The volumes of the knee extensor, knee flexor, adductor, plantar flexor, and dorsiflexor muscle groups and their individual muscles were calculated. After the bed rest, the BR-Tr subjects showed no significant change in the volume in almost all tested muscles; in contrast, the volumes of the four muscle groups significantly decreased in the BR-Cont group ( - 12 % to - 8 %). These results suggest that resistance training during bed rest can prevent the deteriorating of thigh muscles and calf muscles.

Muscle morphology determines muscle function. An objective method to determine muscle volume in vivo will facilitate understanding of basic muscle function and will also provide a valuable tool for the clinician to assess the effectiveness of treatment. In this method-validation study, it is hypothesised that a freehand 3-D ultrasonography system provides a noninvasive method that allows the determination of muscle volume with high accuracy and precision. To test the hypotheses, repeated measurements were performed (1) on cadaver muscles in situ, (2) isolated muscles and (3) live animals. Volume measurements performed with 3-D ultrasonography were compared with measurements based on computed tomography and the water displacement method. The results of this study showed that 3-D ultrasound provided excellent precision and accuracy in the measurements on the isolated muscles and good precision in vivo. It is concluded that 3-D ultrasonography is an innovative technique that allows objective determination of muscle volume in vivo.

After long term of studies from our gait lab, the typical muscular dysbalances by all of our patients with cerebral palsy where pointed out. Now we wanted to examine using the MRT, weather the dysbalances of the hemiparetic musculoskeletal system also show up in discrepancies of the muscle volumes. The MRT slices of the lower extremities were segmented. From this cross sections the muscles volumes were derived. These where analyzed particularly with regard to asymmetries between spastic and healthy side. Hemiparetic patients showed reduced volumes of all muscles on the paretic leg in comparison to the healthy side. The muscles of the thigh of the paretic leg were reduced to 84% in the mean over all muscles and in comparison to the healthy leg. The volume of the muscles of the shank was reduced to 72%, significantly more than the muscles of the thigh. Concerning flexor and extensor muscles located at thigh and shank of the paretic leg there was found significantly the same relative deficit of the muscle volume. Examining the muscle volumes of subjects with different neurogene foot deformities, significant differences of the volume reduction of single muscles appeared within the lower leg.

Objective Magnetic resonance imaging was used to test whether squirrel monkeys with pelvic organ prolapse have reduced pelvic muscle volumes, compared with matched normals. Study design Levator ani and obturator internus volumes obtained from T1-weighted axial scans of matched groups were measured. Muscle volumes and weights were compared for animals necropsied after magnetic resonance imaging. Results Two observers concurred on measures of levator ani and obturator internus (Kendal tau ≥ 0.60 with P R 2 = 0.62, P = .0009). Animals with pelvic organ prolapse did not differ ( P = .67, Wilks multivariate test) from those without pelvic organ prolapse in age, parity, and weight. Levator ani differed between groups (pelvic organ prolapse=520 mm 3 versus normals=392 mm 3 , P = .015) and not sides ( P = .80). The obturator internus did not differ between groups ( P = .29) or sides ( P = .72). Conclusion Magnetic resonance imaging demonstrates that levator ani volumes in parous squirrel monkeys with pelvic organ prolapse were not reduced, suggesting that prolapse is not related to pelvic muscle size reduction in this species.

To elucidate masseter muscle volume. we examined 9 donor bodies by laser scanner. spiral X-ray CT. and water displacement. After the masseter muscle volume expanded as a result of perfusion fixation. shrinkage of muscle occurred. After 3 months, the masseter muscle volume was decreased to 80% with immersion in 40% alcohol. As a result. it is possible to speculate the volume of a living body by measuring the volume of a donor body. There was a 5% error in the measurement of the volume between the spiral X-ray CT and the water displacement. This study suggests that the muscle volume of a living body could be measured by 3-D reconstruction images of CT.