Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Stoerchle, P.
ULTRASOUND MEASUREMENT OF SUBCUTANEOUS ADIPOSE TISSUE THICKNESS: METHODICAL IMPROVEMENTS, INTRA-OBSERVER RELIABILITY IN OVERWEIGHT AND OBESE PERSONS, AND FAT PATTERNING ANALYSES
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Graz Medical University; 2019. pp. 134
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Ahammer Helmut
- Holasek Sandra Johanna
- Müller Wolfram
- Altmetrics:
- Abstract:
- Background: Body composition, health and physical performance are closely related. The most accurate and reliable method for measuring subcutaneous adipose tissue (SAT) thickness is the recently developed and standardised brightness mode ultrasound (US) technique; however, the application of this method has not been tested in overweight and obese people before. The aims of this thesis were: (a) to contribute to the methodical developments of the standardised US technique by testing the applicability of the method in overweight and obese persons, by investigating the skin thicknesses at the eight standardised sites, and by comparing mean SAT thicknesses of eight sites to means of 216 randomly distributed sites. (b) to conduct intra-observer reliability tests in all groups from lean to obese. (c) to analyse the participants' body composition characteristics in terms of fat patterning, amounts of fibrous structures embedded in the SAT, and correlations of SAT with anthropometric indices. Methods: The 82 men and 71 women investigated covered a wide range of SAT thicknesses, and BMI ranged from 17 to 40 kgm-2. The image evaluation software enabled semi-automatic multiple thickness measurements in SAT and quantification of the embedded fibrous structures (fasciae). US measurements were made in accordance with the standardised method at the eight sites: upper abdomen (UA), lower abdomen (LA), erector spinae (ES), distal triceps (DT), brachioradialis (BR), lateral thigh (LT), front thigh (FT) and medial calf (MC). The previously used site external oblique (EO) was replaced by LT. Additionally, in a subset of ten participants, SAT thickness measurements were performed at 216 randomly distributed sites. Skin thicknesses were also measured. Obtainable accuracy of US measurements ranged from about 0.1 mm (at 18 MHz probe frequency) to about 0.3 mm (at 6MHz). Results: The site EO caused major problems in overweight and obese persons, therefore, the new site LT was introduced instead. Mean skin thicknesses were significantly higher in men compared to women at all sites, except for ES, and the thicknesses were also significantly different at all sites (p<0.05). The means from the eight sites (means of SAT thicknesses ranged from 3 to 10mm) overestimated the means obtained from 216 sites because typical fat depot sites are overrepresented in the set of the eight sites. Within this range of SAT thicknesses, the 216-site mean was 0.65 (SD 0.05) times the mean of the eight sites. The intra-observer study resulted in a correlation coefficient of ρ=0.999, the standard error of the estimate (SEE) was 1.1 mm, and 95% of measurements were within ±2.2 mm. In the subgroup with sums of SAT thicknesses below 77mm, 95% of measurements were within ±1.4mm. Except for BR, all sites showed significant differences in median SAT thicknesses between men and women. SAT thickness sums differed significantly when men (median 40.3mm) and women (median 76.0 mm) were compared. Significant sex differences in the amounts of fibrous structures were found at the individual sites ES, DT, LT, FT, MC, and also for the sums of the eight sites (15%, and 9%, respectively). Conclusion: In a wide range of body fatness from extremely lean to obese, high reliability can be expected when using the standardised US method for measuring SAT. The thickness measurement deviations increased with increasing SAT thickness, but the percentages of deviations (with respect to the given SAT thickness) decreased. Pronounced dimorphisms between men and women was found for the following variables: sums of SAT thicknesses, skin thicknesses, amount of fibrous structures embedded in SAT, and in the fat patterning. Therefore, it is of predominant importance to distinguish between men and women when normative datasets are collected, and when searching for cut-off values for medical diagnoses.