Poster Presentation Society of Obstetric Medicine of Australia and New Zealand and Australasian Diabetes in Pregnancy Society Joint Scientific Meeting 2017

Elastography: a novel evaluation of abdominal subcutaneous fat in pregnancy (#107)

Narelle Kennedy 1 2 , Ann Quinton 3 , Michael Peek 4 , Ron Benzie 1 , Ralph Nanan 5
  1. Nepean Hospital, Penrith, NSW, Australia
  2. Nepean Medical School, University of Sydney, Penrith, NSW, Australia
  3. Medical Sonography School of Health, Medical and Applied Science, Central Queensland University, Sydney, NSW, Australia
  4. Department of Obstetrics and Gynaecology, College of Medicine, Biology and Environment The Australian National University, Canberra, NSW, Australia
  5. Charles Perkins Centre, University of Sydney, Sydney, NSW, Australia

Introduction:Adipose tissue(AT) fibrosis is a result of chronic inflammation, attributed to excessive extracellular matrix proteins providing mechanical support in AT(1). An increasing degree of fibrosis in adipose tissue is associated with Body mass index(BMI) and insulin resistance(2). Real-time Ultrasound Elastography(RTE) is a useful tool in assessing fibrosis in liver disease(3) but has not been previously used to assess adipose tissue fibrosis. The variance of abdominal subcutaneous tissue(AST) density was assessed using RTE.  Secondarily to correlate fat thickness and BMI and fat density.

Method:Women(n=210)recruited in early pregnancy. AST was imaged, utilising two anatomical layers, superficial subcutaneous fat(SSAT) and deep subcutaneous fat(DSAT).  Density of adipose tissue was assessed using RTE. Quantitative measures were achieved using two methods, strain values (SV) and ImageJ software to calculate the percentage colour pixels in the Elastography image. Density measures were correlated with BMI and fat thickness.

Results:adipose tissue demonstrated a variance of density; range of SSAT SV(0.04 – 0.49) mean(SD) was 0.2(0.08) DSAT SV range(0.05 – 0.9) mean 0.25(0.1), SV ratio range(0.0 – 2.0) mean 0.84(0.29). Density calculated from colour pixel percent for SSAT range for soft fat was(0.0 - 0.69), mean 0.12(0.13), medium fat, range (0.0 – 0.99), mean 0.59(0.18) and hard fat (0.0 – 1.0), mean 0.29(0.2). DSAT:soft fat range (0.0 - 0.93), mean 0.26(0.21), medium fat, range (0.0 – 0.99), mean 0.59(0.17) and hard fat range (0.0 – 0.92), mean 0.21(0.21). SSAT layer was denser than DSAT. There was poor correlation of tissue density measures with BMI: R2 (0.00 - 0.07) and adipose tissue thickness: R2 (0.01 - 0.02).

Conclusion: Elastography demonstrated density differences in adipose tissue. Overall SSAT was denser than DSAT. There was poor correlation of density with BMI/fat thickness. Elastography analysis correlated with insulin resistance and histology may provide new insights, establishing fundamental information on obesity related disease in pregnancy.

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  2. Spencer M, Yao-Borengasser A, Unal R, Rasouli N, Gurley CM, Zhu B, et al. Adipose tissue macrophages in insulin-resistant subjects are associated with collagen VI and fibrosis and demonstrate alternative activation. American Journal of Physiology-Endocrinology and Metabolism. 2010;299(6):E1016-E27.
  3. Frulio N, Trillaud H. Ultrasound elastography in liver. Diagnostic and interventional imaging. 2013;94(5):515-34.