Epicardial adipose tissue (EAT) thickness on non-gated chest CT as an alternative to EAT volume on cardiac CT.

ABSTRACT

BACKGROUND: Epicardial adipose tissue (EAT) volume is usually measured with ECG-gated computed tomography (CT). Measurement of EAT thickness is a more convenient method; however, it is not clear whether EAT thickness measured with non-gated CT is reliable and at which localization it agrees best with the EAT volume. PURPOSE: To examine the agreement between ECG-gated EAT volume and non-gated EAT thickness measured from various localizations and to assess the predictive role of EAT thickness for high EAT volume. MATERIAL AND METHODS: EAT thickness was measured at six locations using non-contrast thorax CT and EAT volume was measured using ECG-gated cardiac CT (n = 68). The correlation and agreement (Bland-Altman plots) between the thicknesses and EAT volume were assessed. RESULTS: EAT thicknesses were significantly correlated with EAT volume (P < 0.001). The highest correlation (r = 0.860) and agreement were observed for the thickness adjacent to the right ventricular free wall. Also, EAT thickness at this location has a strong potential for discriminating high (>125 cm3) EAT volume (area under the ROC curve=0.889, 95% CI=0.801-0.977; P < 0.001). The sensitivity, specificity, and positive and negative predictive values of EAT thickness for high EAT volume were 76.5%, 88.2%, 68.4%, and 91.8%, respectively, for the cutoff value of 5.75 cm; and 47.1%, 100%, 100%, and 85%, respectively, for the cutoff value of 8.10 cm. CONCLUSION: EAT thickness measured on non-gated chest CT adjacent to the right ventricular free wall is a reliable and easy-to-use alternative to the volumetric quantification and has a strong potential to predict high EAT volume.