Physiological swelling imaging in human calf under stocking compression by sparse Bayesian learning implemented into...

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Physiology

Background:

• Physiological swelling in the human calf is a common concern, often managed with compression stockings.
• Evaluating the effectiveness of different compression pressures in situ is crucial for optimizing treatment.
• Electrical impedance tomography (EIT) offers a non-invasive method for imaging tissue conductivity.

Purpose of the Study:

• To evaluate the in situ treatment effect of various compression pressures on physiological calf swelling using SBL-EIT.
• To reconstruct conductivity distribution to image excessive extracellular fluid in subcutaneous adipose tissue (SAT).
• To investigate the relationship between compression pressure and physiological swelling susceptibility.

Main Methods:

• Sparse Bayesian learning implemented into electrical impedance tomography (SBL-EIT) was used to image calf swelling.
• Eight subjects underwent prolonged standing with three net compression pressures: strong (11.9 mmHg), weak (4.47 mmHg), and control (0.00 mmHg).
• Pre-processing steps were applied to eliminate skin condition and stocking effects before analysis.

Main Results:

• Spatial-mean conductivity (⟨σ⟩α2) was highest with control pressure, followed by weak and strong pressures, across all subjects.
• ⟨σ⟩α2 showed a strong positive correlation with bioelectrical impedance analysis (BIA) inversed impedance (1/zBIA).
• Increased ⟨σ⟩α2 during prolonged standing correlated with individual swelling susceptibilities, influenced by external and internal factors.

Conclusions:

• SBL-EIT is a viable method for assessing the in situ effects of compression on calf physiological swelling.
• Lower compression pressures appear to be more effective in managing extracellular fluid accumulation in subcutaneous adipose tissue.
• Individual swelling susceptibility is influenced by a combination of external factors (posture, circumference) and internal factors (SAT).