Evaluation of morphological changes of intracranial flow diverter stents by flat panel CT angiography

Aim: The main aim of this study was to demonstrate the morphological changes that occur in intracranial flow diverter stents that may alter stent efficacy by flat panel CT angiography technique and to determine the effects of these changes on aneurysm occlusion. Materials and Methods: Patients who underwent flow diverter stenting in the interventional neuroradiology department of our hospital between March 2008 and August 2023, who had clinical and radiological follow-up for at least 6 months, and who had flat panel CT angiography during follow-up were evaluated retrospectively. Admission symptoms, aneurysm sizes, technical success of the procedure, complications that developed during or after treatment, radiological images and clinical examination findings at follow-up were retrospectively evaluated from the records. The lengths, proximal and distal diameters of all stents, the diameter at the narrowest part of the stent in the presence of stenosis and the diameter of the widest segment in the presence of overexpansion were measured at the time of treatment. At 6-month follow-up, flat panel CT angiography was performed. Results: High aneurysm occlusion rates and low morbidity and mortality rates were found in patients treated with flow diverter stents. During treatment, the lengths of the stents increased compared to their nominal lengths, and at 6 months, the proximal and distal diameters increased and the lengths decreased compared to the lengths at the time of treatment. The amount of elongation was found to be higher in the group whose aneurysms were not completely occluded. Conclusion: Flow diverter stents, which are difficult to evaluate with other radiological methods, can be successfully evaluated with flat panel CT angiography thanks to its high spatial resolution and the dynamic remodelling process occurring in the stents can be revealed with this method. Keywords: Endovascular treatment, flow diverter stent, flat panel CT angiography,intracranial aneurysm