Subcutaneous adipose tissue elastosonography in obese patients: a preliminary report

Introduction. Elastosonography is a diagnostic method measur- ing the rigidity or “stiffness” of the tissues. Its main application has been primarly the measurement of hepatic stiffness in patients with chronic liver disease. Recently, the use of new software and technologies has allowed its application to several organs (thyroid, muscle, prostate). The main objective of our study was to test the application of elastosonography to subcutaneous adipose tissue. Materials and Methods. we recruited 12 obese non-diabetic sub- jects referred to the obesity clinic of the SS. Annunziata Hospital of Chieti. A clinical evaluation was performed with measurement of anthropometric parameters and laboratory tests (blood count, cre- atinine, uric acid, AST, ALT, GGT); then the patients underwent abdominal ultrasound with measurement of SAT, preperitoneal and visceral fat (VAT), hepatic elastosonography and SAT. The elastosonography of the SAT was performed by centering the roi in the subcutaneous adipose tissue, positioning the probe 2 cm above the navel along the xiphoumbilical line, between the exter- nal surface of the rectus abdomen and the skin; the final value was derived from an average of 10 measurements. Results. The average age of the subjects examined was 54 years; median BMI was 40, waist circumference 117.5 cm and hip circum- ference 125.5 cm. The median hepatic stiffness was 4.65 kPa. The median stiffness value of the SAT was 9.9 kPa. On statistical analy- sis, E-SAT correlated with preperitoneal fat thickness (p=0.001; rho =0.786), with VAT thickness (p=0.011; rho=0.676), with body weight (p=0.039; rho=0.601) and with the waist circumference (p=0.034; rho=0.613). E-SAT did not correlate with the thickness of the SAT itself (p=0.448; rho=0.231), did not correlate with E-liver (p=0.183; rho= 413) and did not correlate with age of the patients (p=0.795). Conclusions. The elastosonography of the SAT seems to be a fea- sible and repeatable method. Comparative studies and with a larg- er sample size are needed to create a standardized method. The fact that the stiffness value does not correlate with the size of the SAT itself, but with the weight and waist circumference, suggests that the stiffness of the tissue is linked to a histological-tissue re- modeling due to obesity itself, rather than to its actual measurable size.