# Comparative Evaluation of Tissue Attenuation Imaging (TAI) and Ultrasound Attenuation Parameter (UAP) for Noninvasive Quantification and Grading of Hepatic Steatosis

## TL;DR

This study compares TAI and UAP for measuring liver fat and finds TAI to be a reliable, accessible alternative for grading hepatic steatosis.

## Contribution

Proposes TAI as a noninvasive, accessible alternative to UAP for grading hepatic steatosis with defined thresholds.

## Key findings

- TAI showed strong positive correlation with UAP (Spearman's ρ = 0.61, p < 0.001).
- TAI thresholds for steatosis grading were proposed with substantial agreement (κ = 0.78) to UAP-based grading.
- TAI demonstrated an AUC of 0.84 for detecting moderate-to-severe steatosis (≥ S2).

## Abstract

Background and aim: Hepatic steatosis is a major component of chronic liver disease and a key predictor of disease progression. The ultrasound attenuation parameter (UAP) is widely used via transient elastography (TE) for quantifying hepatic fat, but limited access and cost restrict its utility in routine practice. This study aimed to evaluate the correlation between tissue attenuation imaging (TAI) and UAP and to propose reference ranges for grading hepatic steatosis (S0-S3) using TAI as a noninvasive alternative.

Methods: This prospective observational study was conducted at Mann Scanning Centre, Jalandhar, Punjab, India. A total of 120 adult patients undergoing liver evaluation were included. All subjects underwent TE with UAP measurement and ultrasound-based TAI. Steatosis grading (S0-S3) was assigned based on UAP thresholds. Correlation between TAI and UAP was assessed using Spearman's and Pearson's coefficients. Receiver operating characteristic (ROC) curve analysis was performed to derive optimal TAI cutoffs corresponding to each steatosis grade.

Results: TAI showed a strong positive correlation with UAP (Spearman's ρ = 0.61, p < 0.001). TAI values increased progressively across steatosis grades S0 to S3. ROC analysis demonstrated an area under the curve (AUC) of 0.84 for detecting moderate-to-severe steatosis (≥ S2) using TAI. Proposed TAI thresholds for steatosis grading were: S0 (< 0.70 dB/cm/MHz), S1 (0.70-0.79 dB/cm/MHz), S2 (0.80-0.89 dB/cm/MHz), and S3 (≥ 0.90 dB/cm/MHz). The agreement between TAI-based and UAP-based grading was substantial (κ = 0.78).

Conclusions: Tissue attenuation imaging is a reliable and accessible ultrasound-based technique for quantifying hepatic steatosis. It correlates well with UAP and can serve as a practical alternative for steatosis grading in settings where TE is unavailable.