Association of visceral fat area with abdominal skeletal muscle distribution in overweight Japanese adults

Validity of Extended-Field-of-View Ultrasound Imaging to Evaluate Quantity and Quality of Trunk Skeletal Muscles

This study examined the validity of extended-field-of-view (EFOV) ultrasound imaging for evaluating the quantity (cross-sectional area [CSA]) and quality (accumulation of intramuscular fat) of trunk skeletal muscles (rectus abdominis, abdominal oblique and erector spinae) using magnetic resonance imaging (MRI) as a reference. Thirty healthy young men participated in this study. Cross-sectional images of the trunk at the height of the third lumbar vertebra were acquired and compared by EFOV ultrasound imaging and MRI. No significant differences were observed in CSAs between the two methods (0.74 ≤ R² ≤ 0.85). Echo intensities significantly correlated with MRI-derived accumulation of intramuscular fat in each skeletal muscle group. However, the correlation coefficients were relatively low (0.37 ≤ r ≤0.47; p < 0.05). These results indicate that EFOV ultrasound imaging is a reliable method for assessing trunk skeletal muscle CSA. Further research is warranted to find the optimal ultrasound setting for evaluating muscle quality.

Association of Outcomes of Spinal Cord Stimulation for Chronic Low Back Pain and Psoas Measurements Based on Size of Iliopsoas Muscles

INTRODUCTION

Patients experience variable long-term improvement in chronic back pain despite successful spinal cord stimulation (SCS) trials. Iliopsoas (IP) size has been shown to differ between patients with low back pain and healthy controls. In this study, we examine whether IP muscle cross-sectional area (CSA) is associated with SCS outcomes.

MATERIALS AND METHODS

We examined patients for whom we had lumbar MRIs 6.3 years prior to SCS and had baseline and one-year outcome data. Percent change from baseline to one year was calculated for Numeric Rating Scale (NRS), Oswestry Disability Index (ODI), Beck Depression Inventory (BDI), Pain Catastrophizing Scale (PCS), and McGill Pain Questionnaire (MPQ). Correlations between IP muscle CSA, ratio of iliopsoas muscle size to the vertebral body area (P/VBA), and the ratio of iliopsoas muscle size to BMI (P/BMI) were examined. Sex differences were considered.

RESULTS

A total of 73 subjects were included in this study including 30 females and 43 males. Males had significantly larger IP (males 15.70 ± 0.58, females 9.72 ± 0.43; p < 0.001), P/VBA (males 1.00 ± 0.04, females 0.76 ± 0.03, p < 0.001) and P/BMI ratio (males 0.51 ± 0.02, females 0.32 ± 0.01; p < 0.001) than females. In females, P/VBA predicted NRS worst pain scores (β = 0.82, p = 0.004, r² = 0.55) and BDI (β = 0.59, p = 0.02, r² = 0.24). In males, P/BMI was a significant predictor of BDI outcomes scores (β = 0.45, p = 0.03, r² = 0.16). Males who had more muscle mass measured by iliopsoas size had more depression as measured using BDI (p = 0.03, r = 0.61). Females with less muscle mass measured by P/VBA also experienced more depression (p = 0.02, r = 0.74).

CONCLUSIONS

Our study showed that psoas measurements correlated with various pain outcomes specifically. P/VBA was most predictive in females and P/BMI in males. Depression correlated with P/BMI, reinforcing the complex relationship between depression and constant chronic pain. Tertile analyses further showed a relationship between iliopsoas CSA and depression in males and females. We provide preliminary data of sex-specific psoas measurements as a risk factor for worse SCS outcomes.

Paediatric reference values for total psoas muscle area

BACKGROUND

Sarcopenia, the unintentional loss of skeletal muscle mass, is associated with poor outcomes in adult patient populations. In adults, sarcopenia is often ascertained by cross-sectional imaging of the psoas muscle area (PMA). Although children with chronic medical illnesses may be at increased risk for muscle loss because of nutritional deficiencies, physical deconditioning, endocrine anomalies, and systemic inflammation, consistent quantitative definitions for sarcopenia in children are lacking. We aimed to generate paediatric reference values for PMA at two intervertebral lumbar levels, L3-4 and L4-5.

METHODS

In this cross-sectional study, we analysed abdominal computed tomography scans of consecutive children presenting to the emergency department. Participants were children 1-16 years who required abdominal cross-sectional imaging after paediatric trauma between January 1, 2005 and December 31, 2015 in a large Canadian quaternary care centre. Children with a documented chronic medical illness or an acute spinal trauma at presentation were excluded. Total PMA (tPMA) at levels L3-4 and L4-5 were measured in square millimetres (mm² ) as the sum of left and right PMA. Age-specific and sex-specific tPMA percentile curves were modelled using quantile regression.

RESULTS

Computed tomography images from 779 children were included. Values of tPMA at L4-5 were significantly larger than at L3-4 at all ages, but their correlation was high for both girls (r = 0.95) and boys (r = 0.98). Amongst girls, tPMA 50th percentile values ranged from 365 to 2336 mm² at L3-4 and from 447 to 2704 mm² for L4-5. Amongst boys, 50th percentile values for tPMA ranged between 394 and 3050 mm² at L3-4 and from 498 to 3513 mm² at L4-5. Intraclass correlation coefficients were excellent at L3-4 (0.97, 95% CI 0.94 to 0.981) and L4-5 (0.99, 95% CI 0.986 to 0.995). Weight and tPMA were correlated, stratified by sex for boys (L3-4 r = 0.90; L4-5 r = 0.90) and for girls (L3-4 r = 0.87; L4-5 r = 0.87). An online application was subsequently developed to easily calculate age-specific and sex-specific z-scores and percentiles.

CONCLUSIONS

We provide novel paediatric age-specific and sex-specific growth curves for tPMA at intervertebral L3-4 and L4-5 levels for children between the ages of 1-16 years. Together with an online tool (https://ahrc-apps.shinyapps.io/sarcopenia/), these tPMA curves should serve as a reference enabling earlier identification and targeted intervention of sarcopenia in children with chronic medical conditions.

Reliability of size and echo intensity of abdominal skeletal muscles using extended field-of-view ultrasound imaging

PURPOSE

This study aimed to examine the reliability of extended field-of-view (EFOV) ultrasound imaging to evaluate the cross-sectional area (CSA) and echo intensity of abdominal skeletal muscles.

METHODS

Twenty-seven healthy young males (age 18.6 ± 1.0 years, body mass index 20.9 ± 2.8 kg/m², waist circumference 75.0 ± 7.9 cm, body fat 16.6 ± 5.9%) visited the laboratory on 2 days. EFOV ultrasound images of the rectus abdominis, abdominal oblique, and erector spinae muscles were acquired at the height of the third lumbar vertebra with the subject lying on a bed. We then analyzed CSA and echo intensity using ImageJ software and calculated intra-class correlation coefficients (ICC) and the standard error of measurement (SEM).

RESULTS

No significant differences (p = 0.149-0.679) were observed in CSA or echo intensity values for each skeletal muscle between days. ICC and SEM values in CSA for each skeletal muscle ranged between 0.944 and 0.958 and 4.9% and 7.3%, respectively. The corresponding values for echo intensity were 0.851-0.945 for ICC and 5.3-9.7% for SEM.

CONCLUSIONS

The present results indicate that EFOV ultrasound imaging has high repeatability for measuring CSA and echo intensity of abdominal skeletal muscle groups in healthy college-aged males.