Radiation exposure in the intra-arterial nimodipine therapy of subarachnoid hemorrhage related cerebral vasospasm.

The selective intra-arterial nimodipine application for the treatment of cerebral vasospasm (CVS) in patients after spontaneous subarachnoid hemorrhage (sSAH) is widely employed. The purpose of this study is to examine the radiation exposure and to determine local reference levels (RLs) of intra-arterial nimodipine therapy. In a retrospective study design, RLs and achievable dose (AD) were assessed for all patients undergoing (I) selective intra-arterial nimodipine application or (II) additional mechanical angioplasty for CVS treatment. Interventional procedures were differentiated according to the type of procedure and the number of probed vessels. Altogether 494 neurointerventional procedures of 121 patients with CVS due to sSAH could be included. The radiation exposure indices were distributed as follows: (I) RL 74.31 Gy∙cm², AD 59.77 Gy∙cm²; (II) RL 128.34 Gy∙cm², AD 94.48 Gy∙cm². Kruskal-Wallis-test confirmed significant dose difference considering the number of probed vessels (p < 0.001). The mean cumulative dose per patient was 254.87 Gy∙cm² (interquartile range 88.56-315.57 Gy∙cm²). The RLs of intra-arterial nimodipine therapy are substantially lower compared with RLs proposed for other therapeutic interventions, such as thrombectomy or aneurysm coiling. However, repeated therapy sessions are often required, bearing the potential risk of a cumulatively higher radiation exposure.