Quantitative evaluation of insulin-induced abdominal subcutaneous dystrophic tissue using shear wave elastography

Aims/Introduction Subcutaneous dystrophic tissue (DT) produced by insulin injection causes dysglycemia owing to inadequate absorption of insulin. However, precise techniques for measuring DT have not been established. Shear wave elastography (SWE) is an imaging technology that can quantify tissue stiffness. In this study, insulin injection-induced DT was quantified using SWE to generate whole-abdominal wall subcutaneous tissue by three-dimensional (3D) imaging in patients with type 2 diabetes who were treated with multiple insulin injections. Materials and Methods Seven patients with type 2 diabetes were recruited who received long-standing multiple insulin injections. Using SWE, the shear wave velocity (SWV) of DT and control (normal subcutaneous tissue) was measured. Furthermore, two of seven patients underwent whole-abdominal SWE examination to calculate the proportion of DT. A subcutaneous insulin tolerance test was also performed in both the DT and control tissues. Results The SWV in DT was significantly higher than that in the control tissue (2.87 [2.66-2.98] vs 1.29 [1.23-1.44] m/s, P < 0.01). The proportion of the DT volume was 0.67% and 5.21% for two individuals from the entire abdominal subcutaneous tissue volume. The area under the curve for the subcutaneously injected insulin aspart concentration at the DT sites was lower than that of the control tissue (75.0 [52.1-111] vs 116 [86.9-152.5] h*mU/L, P = 0.1). Conclusions SWE can be useful in quantifying abdominal subcutaneous insulin-induced DT, especially the 3D volume of insulin injection-induced DT from the entire abdominal subcutaneous tissue. This study is the first to examine the volume and distribution of abdominal subcutaneous DT using SWE.