Feasibility of non-enhanced CT for assessing longitudinal changes in hepatic steatosis

Abstract

Abstract To evaluate the feasibility of computed tomography (CT) in the assessment of the change in hepatic steatosis (HS) in longitudinal follow-up by employing pathological HS as the reference standard. We retrospectively evaluated 38 living liver donor candidates (27 men and 11 women; mean age, 29.5 years) who underwent liver biopsy twice and had liver CT scans within 1 week of each biopsy. Four readers independently calculated CTL-S index by subtracting spleen attenuation from liver attenuation on non-enhanced CT images. The changes in pathological HS (&Dgr;HS) and CTL-S (&Dgr;CTL-S) between the 1st and 2nd examinations were assessed. The correlation between &Dgr;HS and &Dgr;CTL-S was assessed using the linear regression analysis. Inter-observer measurement error for &Dgr;CTL-S among the 4 readers was assessed using the repeatability coefficient. &Dgr;CTL-S showed a significant correlation with &Dgr;HS in all readers (r\u200a=\u200a0.571–0.65, P\u200a<\u200a.001). The inter-observer measurement error for &Dgr;CTL-S was ±8.9. The &Dgr;CTL-S values beyond the measurement error were associated with a consistent change in HS in 83.3% (13/15) to 100% (15/15), with sensitivities of 47.8 to 79.9% and specificities of 86.7 to 100% for detecting an absolute change of ≥10% in HS among the 4 readers. However, &Dgr;CTL-S values within the measurement error were associated with a consistent change in HS in 43.5% (8/19) to 61.5% (16/26). The change in CTL-S roughly reflects the change in HS during longitudinal follow-up. A small change in CTL-S should not be considered meaningful, while a larger change in CTL-S beyond the measurement error strongly indicates a true change in HS.