Spectral CT-Derived Virtual Non-contrast Imaging and Extracellular Volume of the Liver: Effects of Cirrhosis and Sex.

BACKGROUND

This study evaluated spectral computed tomography-based iodine density quantification for calculation of virtual non-contrast (VNC) images and extracellular volume (ECV) in the context of liver cirrhosis and sex.

METHODS

A total of 156 consecutive patients (35 females) undergoing multiphasic Dual Energy CT (DECT) of the abdomen were retrospectively analyzed. Liver attenuation values and iodine density were quantified on true non-contrast (TNC), arterial-phase VNC (aVNC), and delayed phase VNC (dVNC) images. ECV was quantified using attenuation- (HU) and iodine density- (ID) based methods. Statistical analyses included comparison between TNC and VNC, ECV methods, and subgroup analyses for liver cirrhosis and sex. Logistic regression identified predictors of clinically relevant deviations of VNC.

RESULTS

Both aVNC and dVNC showed significant, but not clinically relevant attenuation deviations (> 10 HU) from TNC with minor sex differences. BMI ≥30, sex, and ascites predicted aVNC deviations; BMI affected dVNC. No clinically relevant deviation was observed between cirrhotic and non-cirrhotic patients overall, but for high- and low-grade cirrhosis. ECV differentiated cirrhosis (AUC 0.74 [HU] and 0.67 [ID]) and varied with Child-Pugh scores. The ID-method showed significant sex-related differences in ECV

CONCLUSION

Iodine density quantification of the liver was influenced by sex and cirrhosis to a limited extent but remained within acceptable diagnostic thresholds. Sex-related findings are limited by male predominance. Elevated BMI may predict relevant deviation and should be considered. ID-ECV estimation yielded comparable results as HU-based evaluation and may indicate higher values in females.