Transcranial magnetic stimulation (TMS) is an increasingly popular tool for stroke rehabilitation. Consequently, researchers have started to explore the use of TMS in pediatric stroke. However, the application of TMS in a developing brain with pathologies comes with a unique set of challenges. The effect of TMS-induced electric fields has not been explored in children with stroke lesions. Here, we used finite element method (FEM) modeling to study how the electric field strength is affected by the presence of a lesion. We created individual realistic head models from MRIs (n = 6) of children with unilateral cerebral palsy due to perinatal stroke. We conducted TMS electric field simulations for coil locations over lesioned and non-lesioned hemispheres. We found that the presence of a lesion can strongly affect the electric field distribution. On the group level, the mean electric field strength did not differ between lesioned and non-lesioned hemispheres but exhibited a greater variability in the lesioned hemisphere. Other factors such as coil-to-cortex distance have a strong influence on the TMS electric field even in the presence of lesions. Our study has important implications for the delivery of TMS in children with brain lesions with respect to TMS dosing and coil placement.

经颅磁刺激（TMS）是中风康复越来越流行的工具。因此，研究人员已开始探索TMS在小儿卒中中的使用。但是，TMS在具有病变的发育中大脑中的应用面临着一系列独特的挑战。TMS诱导的电场的影响尚未在患有中风病变的儿童中探索。在这里，我们使用有限元方法（FEM）建模来研究电场强度如何受病变的存在影响。我们通过MRI（n = 6）对围生期中风导致的单侧脑瘫患儿创建了单独的现实头部模型。我们对病变和非病变半球上的线圈位置进行了TMS电场模拟。我们发现病变的存在会强烈影响电场分布。在组水平上，病变半球和非病变半球的平均电场强度没有差异，但病变半球的平均电场强度表现出更大的可变性。即使存在病灶，线圈到皮质的距离等其他因素也会对TMS电场产生很大影响。相对于TMS剂量和线圈放置，我们的研究对脑损伤患儿的TMS的交付具有重要意义。