Opportunistic Detection of Hepatic Steatosis Using Postcontrast Liver Attenuation at Coronary CT Angiography

Purpose To evaluate the diagnostic performance of postcontrast liver attenuation measured with coronary CT angiography (CCTA) for opportunistic detection of hepatic steatosis and to assess the impact of tube potential variation on optimal attenuation thresholds and overall performance. Materials and Methods This retrospective study included adult patients who underwent CCTA with concomitant unenhanced coronary Agatston scoring (January to December 2025). Moderate-to-severe hepatic steatosis was defined as unenhanced liver attenuation less than 40 HU. Postcontrast liver attenuation was measured using standardized regions of interest. Diagnostic performance was assessed using receiver operating characteristic analysis with Youden index-based threshold determination. Associations between hepatic steatosis, Agatston score categories, and Coronary Artery Disease Reporting and Data System (CAD-RADS) categorizations were evaluated using likelihood ratio χ² tests. Results Among 300 included patients (mean age ± SD, 55.6 years ± 12.0; 170 males), moderate-to-severe steatosis was present in 109 patients (36.3%). Postcontrast liver attenuation demonstrated high diagnostic performance across all settings (area under the receiver operating characteristic curve: 0.88, 0.95, and 0.89 at 100, 120, and 140 kVp, respectively). Optimal thresholds decreased with increasing tube potential (54, 47, and 40 HU at 100, 120, and 140 kVp, respectively). Patients with steatosis had a lower frequency of coronary artery calcium scores of zero (43.7% vs 57.6%) and a higher frequency of coronary artery calcium scores of 101-300 (11.7% vs 4.9%; P = .042), whereas CAD-RADS distribution was similar (P = .12). Conclusion Postcontrast liver attenuation measured with CCTA demonstrated promising diagnostic performance for opportunistic identification of moderate-to-severe hepatic steatosis across different tube potential settings. Hepatic steatosis was associated with coronary calcium burden but not with CAD-RADS categorization. Keywords: CT-Coronary Angiography, Abdomen/GI, Coronary Arteries, Liver Supplemental material is available for this article. © RSNA, 2026.