Quantitative evaluation of CT-perfusion map as indicator of tumor response to transarterial chemoembolization and radiofrequency ablation in HCC patients

• We examine perfusion values in two different categories of treated HCC patients.
• Perfusion parameters are not influenced by TACE or RFA treatments.
• CT-p represents a non-invasive diagnostic technique able to assess treatment response.

PurposeTo assess if radiofrequency ablation (RFA) and transarterial chemoembolization (TACE) may influence the evaluation of perfusion parameters obtained with CT-perfusion (CT-p) in HCC treated patients.Materials and methodsThirty-three consecutive cirrhotic patients with biopsy-proven diagnosis of HCC lesions and candidates to TACE or RFA were included. The CT-p study of hepatic parenchyma and of treated lesions was performed about 1 month after treatment on 16 multidetector CT after injection of 50 mL of non ionic contrast agent (350 mg I/mL) at a flow rate of 6 mL/s acquiring 40 dynamic scans. A dedicated perfusion software which generated a quantitative map of arterial and portal perfusion by means of colour scale was employed.The following perfusion parameters were assessed before and after RFA or TACE treatment: hepatic perfusion (HP), arterial perfusion (AP), blood volume (BV), time to peak (TTP), hepatic perfusion index (HPI).ResultsA complete treatment was obtained in 16 cases and incomplete treatment in the 17 remaining cases. The perfusion data of completely treated lesions were: HP 10.2 ± 6.3; AP 10.4 ± 7; BV 4.05 ± 4.8; TTP 38.9 ± 4.2; HPI 9.9 ± 9.2, whereas in partially treated lesions were: HP 43.2 ± 15.1 mL/s/100 g; AP 38.7 ± 8.8 mL/min; BV 20.7 ± 9.5 mL/100 mg; TTP 24 ± 3.7 s; HPI 61.7 ± 7.5%.In adjacent cirrhotic parenchyma, the parameters of all evaluated patients were: HP 13.2 ± 4; AP 12.3 ± 3.4; BV 11.8 ± 2.8; TTP 43.9 ± 2.9; and HPI 17.1 ± 9.8.A significant difference (P < 0.001) was found for all parameters between residual viable tumor tissue (P < 0.001) compared to successfully treated lesion due to the presence of residual arterial vascular structure in viable portion of treated HCC.ConclusionAccording to our results, CT-p evaluation is not influenced by TACE or RFA treatments, thus representing a feasible technique that allows a reproducible quantitative evaluation of treatment response in HCC patients.