Role of contrast-enhanced color Doppler ultrasonography and dynamic flow in the evaluation of hepatic tumors treated with radiofrequency

The contribution of contrast-enhanced color Doppler ultrasonography (CDUS) and dynamic flow (DF) (Toshiba) in the evaluation following treatment of hepatic tumors with radiofrequency (RF) is discussed. Twenty-seven patients with 34 hepatic tumors were included in this prospective study. The treated tumors measured 10-58 mm in diameter (mean diameter 29 mm). Two tumors were treated twice and one three times, comprising a total of 38 target lesions treated with RF and evaluated by 127 contrast-enhanced CDUS. The results of CDUS follow-up were compared to those of the dynamic MRI at 2 months, 4 months, 6 months and 1 year. Before RF, the injection of Levovist raised the number of vascularized lesions seen with unenhanced Doppler from 44% to 79%. All the non-vascularized lesions were metastases. Twenty-four hours after RF, four tumors presented an enhancement with Levovist, in which two were insufficiently treated lesions. Twenty-one treated tumors have been followed-up jointly by CDUS and MRI at the same time at 2 months, 20 at 4 months, 12 at 6 months and nine at 1 year. Compared to the MRI and the evolution, the CDUS presented a sensitivity of 100% and a specificity of 90% for the detection of progressive recurrence. The preliminary results show that the CDUS is useful to confirm the absence of detectable vascularity after treatment with RF ablation, whereas the presence of enhancement must be confirmed by MRI.