An easily overlooking imaging manifestation of hemorrhage occurred during the performance of embolization therapy for intracranial aneurysm: the slowed blood flow sign

Objective To analyze the imaging manifestations of bleeding due to ruptured intracranial aneurysm occurred during the performance of endovascular embolization for intracranial aneurysm.Methods A total of 358 patients with intracranial aneurysm,who were treated with endovascular embolization,were enrolled in this study.The clinical data were retrospectively analyzed.Of the 358 patients,intracranial hemorrhage that occurred during the procedure was seen in 10.Of the 10 patients having hemorrhage,stent-assisted coil embolization was carried out in 4,dual-catheter coil embolization was employed in 2,and simple coil embolization was performed in 4.Postoperative symptomatic management was adopted in 7 patients,and craniotomy decompression drainage was used in 3 patients.The clinical results were analyzed.Results During the performance of coil embolization contrast extravasation and transient slowed blood flow within the parent artery were seen in 8 cases.The steel coil stuck out from the aneurysmal wall in five cases,the micro-catheter protruded from the aneurysmal wall in one case,and micro-guidewire penetrated the aneurysmal wall in two cases.In two cases,angiography performed during coil embolization procedure showed that only slowed blood flow was seen,and neither contrast extravasation nor penetration of the aneurysmal wall by micro-catheter,micro guidewire or coil could be found.However,postoperative CT scanning confirmed the presence of bleeding in these two cases.Of the 10 patients with ruptured intracranial aneurysm,complete embolization was obtained in 9 and partial embolization was obtained in one case.Postoperative symptomatic management was adopted in 7 patients,and craniotomy decompression drainage was used in 3 patients.After the treatment,six patients recovered well,one patient had transient oculomotor paralysis,and three patients died from intracranial hypertension.Conclusion Slowed blood flow within the parent artery that is caused by the bleeding due to the rupture of intracranial aneurysm occurred during the performance of endovascular embolization for intracranial aneurysm is an easily-neglected angiographic sign.The presence of this sign is closely correlated with the patient's prognosis.