Hepatic transit time : indicator of the therapeutic response to radiofrequency ablation of liver tumours

The aim of this study was to evaluate changes of hepatic transit time (HTT) in patients treated by radiofrequency ablation (RFA). Five consecutive patients (2 females, 3 males; mean age 66 years) referred for treatment of liver neoplasm with percutaneous application of RFA were included in this study. The HTT of contrast agent (Sonovue(R); Bracco International B.V., Amsterdam, The Netherlands) was measured in patients with liver metastases on the basis of time intensity curve (TIC(R)) before and after RFA, respectively. Changes of HTT before vs after RFA were compared with therapeutic response based on three-phase dynamic CT or MRI. Before RFA HTT in all 5 patients was less than 10 s (mean 6.2+/-1.5 s). After RFA HTT in patients with complete therapeutic response was 11.3+/-1.2 s, whereas two patients with incomplete treatment showed unchanged HTT below 10 s (mean 6.3+/-1.8 s). Successful RFA leads to a normalization in HTT. HTT using ultrasound contrast agent appears to provide a new and alternative approach in assessing the therapeutic effect of RFA in liver metastases.