Irreversible electroporation (IRE) is an ablation procedure in which cell death is induced by ultrashort electrical pulses. In this unicentric retrospective study we investigated the influence of needle positioning on ablation success. 15 IREs with residual tumor after ablation, detected in the first follow-up MRI, were included, and compared with 30 successful ablations. Evaluation of needle geometry revealed significantly higher values for needle divergence (NDiv, 7.0° vs. 3.7°, p = 0.02), tumor-center-to-ablation-center distance (TACD, 11.6 vs. 3.2 mm, p < 0.001), tumor-to-needle distance (4.7 vs. 1.9 mm, p = 0.04), and tumor diameter per needle (7.5 vs. 5.9 mm/needle, p = 0.01) in patients with residual tumor. The average number of needles used was higher in the group without residual tumor after ablation (3.1 vs. 2.4, p = 0.04). In many cases with residual tumor, needle depth was too short (2.1 vs. 6.8 mm tumor overlap beyond the most proximal needle tip, p < 0.01). The use of a stereotactic navigation system in 10 cases resulted in a lower NDiv value (2.1° vs. 5.6°, p < 0.01). Thus, correct needle placement seems to be a crucial factor for success and the assistance of a stereotactic navigation system might be helpful. As most important geometrical parameter TACD could be identified. Main reasons for high TACD were insufficient needle depth and a lesion location out of the needle plane.

不可逆电穿孔（IRE）是一种消融过程，其中细胞死亡是由超短电脉冲引起的。在这项单中心回顾性研究中，我们研究了针头定位对消融成功的影响。包括15例消融后残留肿瘤的IRE（在首次随访MRI中检测到），并与30例成功消融进行了比较。针头几何形状的评估显示，针头发散度（NDiv，7.0°vs. 3.7°，p  = 0.02），肿瘤中心至消融中心距离（TACD，11.6 vs. 3.2 mm，p  <0.001）明显更高，肿瘤到针的距离（4.7 vs. 1.9 mm，p  = 0.04）和每针的肿瘤直径（7.5 vs. 5.9 mm /针，p = 0.01）残留肿瘤患者。消融后无残留肿瘤的组中使用的平均针数更高（3.1 vs. 2.4，p  = 0.04）。在许多残留肿瘤的病例中，针头深度过短（超过最靠近的针尖的2.1毫米对6.8毫米肿瘤重叠，p  <0.01）。10例中使用立体定向导航系统导致NDiv值较低（2.1°与5.6°，p  <0.01）。因此，正确放置针头似乎是成功的关键因素，而立体定位导航系统的帮助可能会有所帮助。作为最重要的几何参数，TACD可以被识别。高TACD的主要原因是针头深度不足和位于针头平面外的病变部位。