Hepatic Steatosis Detection Using Differential Effective Permittivity

Hepatic steatosis is a disorder with high prevalence among obese people. Traditional imaging modalities are more common in hepatic steatosis diagnosis, but they are not suitable for monitoring or treatment evaluation. This study aims at developing a new technique suitable for electromagnetic (EM) tool in the microwave band to differentiate steatotic from nonsteatotic liver. A differential permittivity estimation method for hepatic steatosis detection is proposed. First, the effective permittivity of the right side of the torso is estimated based on the phase difference of EM waves traveling along symmetric paths within the torso. Then, permittivity modeling and statistical frequency selection are performed to model the estimated values and to extract reliable frequency samples. Finally, the percentage of the difference between the permittivity of the left and right sides of the torso is calculated over the selected samples. The effectiveness of the proposed method is validated using simulated signals and phantom measurements. The analyzed results reveal higher contrast between the average permittivity of the left and right sides of the torso for cases with hepatic steatosis (average contrast of 29.2%) compared to those with healthy liver (average contrast of 7.9%). The proposed method can differentiate between steatotic and nonsteatotic liver. It is suitable for clinical applications due to its robustness to unwanted noise and interferences, as well as errors in placement of sensors. The results verify the potential of EM devices, which could overcome shortcomings of traditional imaging techniques by being safe, cost-effective, and portable.