Spectral CT Imaging In The Differential Diagnosis Of Hepatic Cyst And Unilocular Hepatic Cystic Echinococcosis

Objective:To investigate the value of spectral CT imaging in differential diagnosis of hepatic cyst (HC) and unilocular hepatic cystic echinococcosis (UHCE). Methods In this retrospective study, thirty-nine patients with 19 HC and 20 UHCE were included. All the patients underwent plain CT and tri-phase enhanced CT with single-source dual-energy mode, Material decomposition images and monochromatic images (40-140KeV) were reconstructed. The iodine concentration(IC),water concentration(WC)and the effective-Z were measured for lesions, normal liver parenchyma and aorta in each phase.The normalized iodine concentration (NIC) and lesion-to-normal parenchyma iodine concentration ratio (LNR) were calculated. Statistical analyses{two-sample t test, non-parametric rank sum test, and area under the receiver operating characteristic curve (A [z])} were performed. Results The mean CT values of monochoromatic energy with 40 KeV and 50 KeV in HC were significantly lower than that in UHCE during the NCP, AP and VP.The IC during all scan phases and effective-Z values during the NCP、AP and VP in HC were significantly lower than that in uHCE (Both P<0.05).The mean NIC for HC were significantly higher than that of uHCE (P<0.05).The mean WC during the AP for HC were lower than that of uHCE (P<0.05).The combination of monochromatic CT values on 40 KeV had highest sensitivity (100%) and specificity (75%) for differentiating HC and UHCE. Conclusion Quantitative spectral CT imaging has been a promising potential for diagnostic differentiation of HC and UHCE.