Comparison between 80 kV, 100 kV and 120 kV CT protocols in the assessment of the therapeutic outcome in HCC

Abstract

Aim: To compare the signal-to-noise ratio (SNR) and effective dose at low dose (80-100 kV) contrast-enhanced computed tomography (CT) to conventional contrast-enhanced CT (120 kV) in the assessment of the therapeutic outcome in patients with hepatocellular carcinoma (HCC) treated by thermal ablation and/ or trans-arterial chemo-embolization (TACE). Materials and methods: Twenty-one cirrhotic patients (15 male and 6 female, 71 years ± 15) with HCC(s) were referred to contrast-enhanced CT to assess therapeutic outcome after thermal ablation (n=7) or TACE (n=7) or thermal ablation and TACE (n=7). CT examination was performed at 120 kV after 370 mgI/ mL contrast injection (120 kV-370 mgI/mL) before treatment, 100 kV after 370 mgI/mL contrast injection (100 kV-370 mgI/mL) at 3 months and 100 kV after 400 mgI/mL contrast injection (100 kV-400 mgI/mL) 6 months after treatment, and 80 kV after 400 mgI/mL contrast injection (100 kV-400 mgI/mL) at 12, 18 and 24 months after treatment. The SNR was calculated by drawing a region-of-interest in hepatic parenchyma and abdominal fat. Results: 120 kV-370 mgI/mL vs. 100 kV-370 mgI/mL vs. 100 kV-400 mgI/mL vs. 80 kV-400 mgI/mL did not differ in SNR (3.4 ± 1.2 vs. 2.9 ± 1.16 vs. 2.9 ± 0.5 vs. 2.2 ± 1; ANOVA test, P=0.41) while differed in effective dose (27.9 ± 8.1 vs. 17.2 ± 4.6 vs. 19.2 ± 5.2 vs. 14 ± 5.8 mSv; ANOVA test, P=0.002). Conclusion: Contrast-enhanced CT at 80-100 KV after high concentration iodinated contrast media injection does not reduce SNR but provides a significant reduction in the effective dose in cirrhotic patients undergoing follow-up after thermal ablation and/or TACE.