Retrospective analysis of intracranial aneurysms after flow diverter treatment including color-coded imaging (syngo iFlow) as a predictor of aneurysm occlusion

Purpose Flow Diverters (FD) have immensely extended the treatment of cerebral aneurysms in the past years. Complete aneurysm occlusion is a process that often takes a certain amount of time and is usually difficult to predict. Our aim was to investigate different syngo iFlow parameters in order to predict aneurysm occlusion. Methods Between 2014 and 2018 patients with unruptured cerebral aneurysms treated with a FD were reviewed. Aneurysm occlusion and complication rates have been assessed. In addition, various quantitative criteria were assessed using syngo iFlow before, after the intervention, and after short and long-term digital subtraction angiography (DSA). Results A total of 66 patients hosting 66 cerebral aneurysms were included in this study. 87.9% (n = 58) aneurysms in the anterior and 12.1% (n = 8) in the posterior circulation were treated. Adequate aneurysm occlusion at long-term follow-up (19.05 +/- 15.1 months) was achieved in 90.9% (n = 60). Adequately occluded aneurysm revealed a significantly greater peak intensity delay (PI-D, p = 0.008) and intensity decrease ratio (ID-R, p < 0.001) compared to insufficiently occluded aneurysms. Increased intra-aneurysmal contrast agent intensity (>100%) after FD implantation resulted in an ID-R < 1, which was associated with aneurysm growth during follow-up DSA. Retreatment with another FD due to foreshortening and/or aneurysm growth was performed in 10.6% (n = 7). Overall morbidity and mortality rates were 1.5% (n = 1) and 0%. Conclusion The applied syngo iFlow parameters were found to be useful in predicting adequate aneurysm occlusion and foresee aneurysm growth, which might indicate the implantation of another FD.