DynaCT imaging for intraprocedural evaluation of flow-diverting stent apposition during endovascular treatment of intracranial aneurysms

The treatment of large, complex intracranial aneurysms is being increasingly performed using flow-diverting stents (FDS) such as the Pipeline Embolization Device (PED; ev3, Irvine, CA, USA). Malapposition of a FDS to the parent artery wall decreases the likelihood of aneurysm obliteration and increases the risk of both immediate and delayed complications. DynaCT scanning (Siemens Medical Solutions, Erlangen, Germany) is a novel imaging modality which uses a flat plane detector to generate CT images using the same C-arm employed for digital subtraction angiography. We present a 40-year-old woman with an unruptured, 11 mm cavernous internal carotid artery aneurysm who was treated with endovascular obliteration using a PED. Intraprocedural DynaCT scan performed after PED deployment demonstrated incomplete stent apposition to the parent vessel which could not be detected on digital subtraction angiography alone. Balloon angioplasty was performed to improve apposition of the stent to the vessel wall. There were no procedural or clinical complications. The aneurysm shrank in size at follow-up angiography 6 months after the procedure and will be monitored for progressive occlusion. While gross stent malapposition is readily evident after stent deployment, minor instances of malapposition may be undetectable by standard angiography. Therefore the use of DynaCT imaging may improve intraprocedural stent visualization and potentially avert long-term endovascular aneurysm treatment complications associated with inadequate stent apposition.