The value of virtual non-contrast images derived from dual-energy spectral CT in the short-term efficacy assessment of hepatocellular carcinoma after TACE

Abstract

Purpose

To explore the clinical utility of virtual non-contrast (VNC) images from dual-energy spectral CT (DEsCT) in short-term follow-up of hepatocellular carcinoma (HCC) after transarterial chemoembolization (TACE).

Methods

66 HCC patients with DEsCT 4–6 weeks post-TACE were retrospectively enrolled. VNC images were generated from arterial (VNC_AP) and portal venous phase (VNC_PVP) images. Beam-hardening artifacts surrounding lipiodol were assessed on true non-contrast (TNC) and both VNC images. Lipiodol removal degree was classified into 4 grades at 25 % intervals on both VNC images. Residual viable tumor (RVT) was diagnosed using contrast-enhanced CT or MRI. CT attenuation values of RVT, adjacent normal hepatic parenchyma (ANHP), and lipiodol removal area (LRA) were compared among TNC and VNC images. Diagnostic performance of CT attenuation values on VNC images was compared for the three areas.

Results

34 patients showed beam-hardening artifacts surrounding lipiodol on TNC images, which were reduced or eliminated on VNC_AP and VNC_PVP images in 28 and 26 cases. All HCCs showed good lipiodol removal on both VNC images, with 7 lesions at Grade 3 and 59 lesions at Grade 4. On TNC images, significant CT attenuation value differences were found between LRA and ANHP, and LRA and RVT (P < 0.001), but not between RVT and ANHP (P > 0.05). Both VNC images showed good diagnostic efficacy for these three areas, with LRA having the lowest value.

Conclusion

VNC images demonstrate superior lipiodol removal efficacy and beam-hardening artifacts reduction, facilitating precise RVT delineation and TACE-induced necrosis assessment, complementing contrast-enhanced CT for TACE efficacy assessment in HCC.