Estimation of controlled attenuation parameter-based liver steatosis via raw ultrasound data from handheld devices

Assessment of liver steatosis is primarily performed through visual evaluation during ultrasound examinations. A more objective approach relies on quantifying ultrasound attenuation, typically using devices such as the FibroScan® or elastography integrated into high-end ultrasound systems-which offer limited accessibility. By contrast, handheld ultrasound devices (HHUDs) are more affordable and widely available. Using raw ultrasound data to get deeper insights into liver tissue characteristics could turn HHUDs into valuable diagnostic tools. We hypothesized that the frequency-specific attenuation of raw ultrasound data acquired with handheld devices correlates with the controlled attenuation parameter (CAP) obtained through vibration-controlled transient elastography via FibroScan.

In an exploratory, single-center study, raw data from 395 participants scheduled for CAP measurement were collected using HHUDs. Of these, 304 participants were included in the final analysis; 91 were excluded due to incomplete data. Using the raw data from the HHUDs, a method based on short-time fast Fourier transform was applied to calculate the frequency-specific attenuation. The results were then correlated with the CAP values.

Overall, the attenuation of the radiofrequency data showed a strong linear correlation with CAP values ( $r=0.672$ , $p<0.001$ ), although the strength of correlation varied significantly across frequencies (r_min = 0.443 at 0.75 MHz, r_max = 0.721 at 3.75 MHz), with the highest correlation, equaling results from studies with high-end ultrasound devices.

HHUDs capable of acquiring raw data may serve as objective and accessible screening tools for liver steatosis, potentially improving treatment monitoring.