Bone marrow fat fraction assessment in regard to physical activity: KORA FF4-3-T MR imaging in a population-based cohort.

OBJECTIVES: To establish the effect of different degrees and kinds of physical activity on bone marrow fat (BMAT) content at different anatomical locations in a population-based cohort study undergoing whole-body MR imaging. METHODS: Subjects of the KORA FF4 study without known cardiovascular disease underwent BMAT fat fraction (FF) quantification in L1 and L2 vertebrae and femoral heads/necks (hip) via a 2-point T1-weighted VIBE Dixon sequence. BMAT-FF was calculated as mean value (fat image) divided by mean value (fat + water image). Physical activity was determined by self-assessment questionnaire regarding time spent exercising, non-exercise walking, non-exercise cycling, and job-related physical activity. RESULTS: A total of 385 subjects (96% of 400 available; 56 ± 9.1 years; 58% male) were included in the analysis. Exercise was distributed quite evenly (29% > 2 h/week; 31% ~ 1 h/week (regularly); 15% ~ 1 h/week (irregularly); 26% no physical activity). BMAT-FF was 52.6 ± 10.2% in L1, 56.2 ± 10.3% in L2, 87.4 ± 5.9% in the right hip, and 87.2 ± 5.9% in the left hip (all p < 0.001). Correlation of BMAT-FF between spine and hip was only moderate (r 0.42 to 0.46). Spinal BMAT-FF, but not hip BMAT-FF, was inversely associated with exercise > 2 h/week (p ≤ 0.02 vs. p ≥ 0.35, respectively). These associations remained significant after adjusting for age, gender, waist circumference, and glucose tolerance. No coherent association was found between BMAT-FF and physical activity in the less active groups. CONCLUSIONS: In our study, exercise was inversely correlated with vertebral BMAT-FF, but not hip BMAT-FF, when exercising for more than 2 h per week. Physical activity seems to affect the spine at least preferentially compared to the hip. KEY POINTS: • In our population-based cohort, at least 2 h of physical activity per week were required to show lower levels of bone marrow adipose tissue fat fraction in MRI. • Physical activity seems to affect bone marrow adipose tissue at least preferentially at the spine in contrast to the proximal femur.

Assessment of the Influence of Diabetes mellitus and Malnutrition on the Postoperative Complication Rate and Quality of Life of Patients in a Clinic Focused on Trauma Surgery. / Einschätzung der Auswirkungen eines Diabetes mellitus und einer Mangelernährung auf die postoperative Komplikationsrate und Lebensqualität von Patienten in einer unfallchirurgischen Schwerpunktklinik.

BACKGROUND: The prevalence of diabetes mellitus (DM) or malnutrition in hospitalised patients depends on the clinical domain, but is much higher than in the normal population. In trauma surgery, this increase is frequently associated with more postoperative complications and constantly rising costs. In addition, the quality of life of this target group is decreased, but there are only limited data from departments of traumatology and/or orthopaedics. Therefore, we aim to analyse the factors influencing the postoperative complication rate as well as the quality of life of orthopaedic and trauma patients. METHODS: Within this prospective trial in the period of 06/2014 to 02/2017, we analysed data of 1643 patients from traumatology - geriatric and septic traumatology - as well as endoprosthetics with regard to the clinical outcome, the complication rate and the quality of life (Short Form Health Survey 36, SF-36) associated with diabetes mellitus (DM) and the nutritional status (Nutritional Risk Screening 2002, NRS). RESULTS: Within our hospitalised group of trauma patients, the prevalence of diabetes mellitus was 12.4% and the risk for malnutrition (NRS ≥ 3) was 18.3%, which is much higher than in the normal population (DM 7.2%). Patients suffering from diabetes mellitus had significantly more complications than patients without diabetes mellitus. Similar results were found when comparing patients with a risk of malnutrition to the patients without. Furthermore, patients with DM evaluate their subjective quality of life lower than do patients without DM in the most domains of the SF-36, especially in the subjective-physical domains, while patients with NRS ≥ 3 assess their quality of life as being lower than do patients without a risk of malnutrition in all domains of the SF-36 (physical and mental). Additionally, we showed that reduced nutritional status has a greater influence on the decline in quality of life than did diabetes mellitus. CONCLUSION: Both diabetes mellitus and malnutrition seems to influence the subjective quality of life and the complication rate of hospitalised trauma patients. A nationwide data collection and targeted interventions within the frame of interdisciplinary cooperation are necessary. In this way, the postoperative complication rate as well as associated higher treatment costs could be reduced.

Assessment of the degree of abdominal myosteatosis by magnetic resonance imaging in subjects with diabetes, prediabetes and healthy controls from the general population.

OBJECTIVES: Intra- and intermyocellular lipid deposition and adipose tissue are part of glucose homeostasis and insulin resistance; however, their role in type 2 diabetes mellitus (T2DM) remains unclear. We assessed differences in the degree of abdominal myosteatosis among subjects with T2DM and prediabetes. MATERIALS AND METHODS: Asymptomatic subjects from the general population were classified as subjects with T2DM, prediabetes or healthy controls and underwent multi-echo Dixon magnetic resonance imaging (MRI) (TR 8.90 ms, six echo times, flip-angle 4°). Abdominal myosteatosis was quantified as proton-density fat-fraction (PDFFmuscle) by a standardized segmentation-algorithm. Cardiometabolic risk factors were prospectively obtained in a comprehensive health assessment and visceral and subcutaneous adipose tissue (VAT and SAT) were quantified semi-automatically. Uni- and multivariate quantile regression were used to examine associations. RESULTS: Among 349 included subjects (mean age: 56.0 ±â€¯8.0years, 56.7% males), 45 were classified as subjects with T2DM and 84 with prediabetes (12.9% and 24.1%; respectively). Median PDFFmuscle was significantly higher in subjects with T2DM and prediabetes compared to healthy controls (13.1% (IQR10.5-16.6%); 11.1% (IQR8.9-15.0%) and 10.1% (IQR7.5-13.3%); respectively, p < 0.001). The observed differences were independent of age and gender (all p < 0.002) but attenuated after adjustment for BMI (ß: -0.02, 95%CI: -1.49 to 1.44, p = 0.974; ß: 0.47, 95%CI: -0.91 to 1.86, p = 0.506; prediabetes and T2DM, respectively). This effect was attributable to VAT, which remained independently associated with PDFFmuscle after full adjustment (ß: 0.01, 95%CI: 0.01-0.02, p = 0.002). CONCLUSIONS: There are significant differences in the degree of abdominal myosteatosis between subjects with T2DM, prediabetes and healthy controls, that may be confounded by VAT. However, abdominal myosteatosis by MRI might serve as a cardiometabolic imaging-biomarker, specifically in the setting of impaired glucose metabolism.

Inter- and intra-observer variability of an anatomical landmark-based, manual segmentation method by MRI for the assessment of skeletal muscle fat content and area in subjects from the general population.

OBJECTIVES: Changes in skeletal muscle composition, such as fat content and mass, may exert unique metabolic and musculoskeletal risks; however, the reproducibility of their assessment is unknown. We determined the variability of the assessment of skeletal muscle fat content and area by MRI in a population-based sample. METHODS: A random sample from a prospective, community-based cohort study (KORA-FF4) was included. Skeletal muscle fat content was quantified as proton-density fat fraction (PDFF) and area as cross-sectional area (CSA) in multi-echo Dixon sequences (TR 8.90 ms, six echo times, flip angle 4°) by a standardized, anatomical landmark-based, manual skeletal muscle segmentation at level L3 vertebra by two independent observers. Reproducibility was assessed by intraclass correlation coefficients (ICC), scatter and Bland-Altman plots. RESULTS: From 50 subjects included (mean age 56.1 ± 8.8 years, 60.0% males, mean body mass index 28.3 ± 5.2) 2'400 measurements were obtained. Interobserver agreement was excellent for all muscle compartments (PDFF: ICC0.99, CSA: ICC0.98) with only minor absolute and relative differences (-0.2 ± 0.5%, 31 ± 44.7 mm2; -2.6 ± 6.4% and 2.7 ± 3.9%, respectively). Intra-observer reproducibility was similarly excellent (PDFF: ICC1.0, 0.0 ± 0.4%, 0.4%; CSA: ICC1.0, 5.5 ± 25.3 mm2, 0.5%, absolute and relative differences, respectively). All agreement was independent of age, gender, body mass index, body height and visceral adipose tissue (ICC0.96-1.0). Furthermore, PDFF reproducibility was independent of CSA (ICC0.93-0.99).  Conclusions:  Quantification of skeletal muscle fat content and area by MRI using an anatomical landmark-based, manual skeletal muscle segmentation is highly reproducible. Advances in knowledge: An anatomical landmark-based, manual skeletal muscle segmentation provides high reproducibility of skeletal muscle fat content and area and may therefore serve as a robust proxy for myosteatosis and sarcopenia in large cohort studies.