Fig. 6

Receiver-operating characteristic (ROC) curves for determination of cutoff value of lesion length and comparison of the success rate between signal access and dual access groups. A1. In group 1 (unidirectional technique group), the cut-off value of lesion length was predicted to be 6.5 cm, with 70% sensitivity and 78% specificity, respectively. A2. Chi-square test showed a significant difference of success rate between the length of lesion which was shorter and longer than cutoff value of 6.5 cm in group 1. B1. In group 2 (dual access group), lesion length had no significant influence on technique success rate. B2. Technical success rate was not significantly linked to the length of lesion in group 2. AUC, area under ROC curve