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Value of the Ultrasound Attenuation Index for Noninvasive Quantitative Estimation of Hepatic Steatosis
Author(s) -
Kwon Heon-Ju,
Kim Kyoung Won,
Lee So Jung,
Kim So Yeon,
Lee Jong Seok,
Kim Hyoung Jung,
Song Gi-Won,
Kim Sun A,
Yu Eun Sil,
Lee Jeongjin,
Hwang Shin,
Lee Sung Gyu
Publication year - 2013
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/jum.2013.32.2.229
Subject(s) - steatosis , medicine , interquartile range , echogenicity , fatty liver , nuclear medicine , ultrasound , radiology , disease
Objectives To assess the value of the ultrasound (US) attenuation index for noninvasive estimation of hepatic steatosis and determine its optimal cutoff value for severe steatosis in potential living liver donors. Methods Two hundred forty potential donors underwent US‐guided biopsy. The target site was scanned at 4 and 8 MHz. On the sonogram, the observer drew 3 × 3‐mm square regions of interest in superficial (3‐cm) and deep (5‐cm) areas. The attenuation index was defined as the difference between superficial and deep echogenicity/superficial echogenicity × 100. On biopsy specimens, replacement of hepatic parenchyma was evaluated on a percentage scale. Severe steatosis was defined as macrovesicular fatty change of 30% or greater. Spearman rank correlation (ρ) was used to determine correlation coefficients between the attenuation index and steatosis degree; receiver operating characteristic analysis was performed to determine the optimal attenuation index cutoff value for severe steatosis. Results The median steatosis degree was 3% (interquartile range [IQR], 0%–10%). Severe steatosis was found in 10 donors. The attenuation index ranged from –27.4 to 36.6 (median, 4.0; IQR, –1.6–10.4) at 4 MHz and –18.0 to 78.1 (median, 14.5; IQR, 7.2–21.9) at 8 MHz. There was a minimal positive correlation between steatosis and the attenuation index at 4 MHz (total steatosis: ρ = 0.339; P < .001; macrovesicular steatosis: ρ = 0.360; P < .001). However, there was a significant moderate correlation between steatosis and the attenuation index at 8 MHz (total steatosis: ρ = 0.669; P < .001; macrovesicular steatosis: ρ = 0.645; P < .001). The optimal attenuation index cutoff value for severe steatosis at 8 MHz was 31.0. Conclusions The US attenuation index at 8 MHz is a useful indicator for noninvasive quantitative estimation of hepatic steatosis and diagnosis of severe steatosis in potential living liver donors.