Objective: It has reported that the stent for the treatment of a cerebral aneurysm has low visibility under fluoroscopy. Cone-Beam CT (CBCT) images using the diluted contrast medium are useful for the evaluation of the positional relationship between the stent, the aneurysm, and the parent artery. However, the visibility of CBCT images changes depending on the dilution ratio (DR) of the contrast medium. Therefore, determination of an appropriate DR is important. The purpose of this study was to determine the optimal DR using the digital value of CBCT images and assessed the effectiveness of it for the neuroendovascular therapy for a cerebral aneurysm using a stent.

Methods: In the phantom study, at each DR, we calculated the digital value of the stent, diluted contrast medium, and background using self-made phantom. In the clinical study, from June 2017 to March 2018, we assessed the optimal DR in the neuroendovascular cases using Neuroform Atlas and CBCT visually and quantitatively.

Results: There was a positive relation between the DR and the contrast value among the stent and the diluted contrast medium. Also, there was a negative association between the DR and the contrast value among the stent and the background. The visual and quantitative evaluation showed the same tendency.

Conclusion: It was suggested that the quantitative evaluation method using the digital value of CBCT became an important factor for determining the appropriate DR of the contrast medium for the neuroendovascular therapy for a cerebral aneurysm using a stent.

Objective: A fusiform, wide-necked, and medially projecting aneurysm that arises from the ventral wall of the internal carotid artery is difficult to treat. We report two cases of ruptured ventromedially projecting C1 aneurysms treated by coil embolization in the acute stage after aneurysmal subarachnoid hemorrhage.

Case presentations: Case 1: A 55-year-old female, ruptured right ventromedially projecting C1 aneurysm was treated with a double catheter coiling technique around the apex of the dome and she was discharged without neurological deficits. One-year follow-up angiography demonstrated a coil compaction. Therefore, we are planning additional treatment if necessary. Case 2: A 75-year-old male, ruptured left ventromedially projecting C1 aneurysm was intended for treatment with a double catheter coiling technique, but the coil was not stabilized in the aneurysm. Therefore, the stent was placed and embolization was performed. In-stent thrombus occurred during embolization, resulting in postoperative ischemic complications.

Conclusion: For the acute phase treatment strategy of the ruptured ventromedially projecting C1 aneurysm, embolization around the rupture site is the primary choice. If necessary, additional treatment with a stent is performed during the chronic stage.

Objective: There is no certain treatment strategy for large or giant cerebral aneurysms presenting with multiple recurrences. We experienced a large basilar trunk aneurysm presenting with multiple recurrences after endovascular treatment, treated previously with neuroform stent, and thereafter several Low-profile Visualized Intraluminal Support device (LVIS) stents were deployed inside the existing neuroform stent successfully.

Case Presentations: A large basilar trunk aneurysm was incidentally found with brain magnetic resonance imaging on a 47-years-old male when he was admitted due to pontine infarction. Subsequently, stent-assisted coil embolization was performed using the neuroform stent for the treatment of the large aneurysm. A total of three additional procedures with coil embolization were performed during the following 3 years. When he was 54 years old, aneurysm growth became symptomatic. To arrest the continuation of aneurysmal growth by flow alteration with braided stents, three LVIS stents were successfully deployed inside of existing neuroform stent.

Conclusion: Deployment of multiple LVIS stents could become one of the treatment options for large basilar trunk aneurysm presenting with multiple recurrences.

Objective: Right aortic arch is an uncommon anatomical anomaly. Therefore, it is rare to encounter patients with such condition in clinical settings. Herein, we report the case of a man with symptomatic internal carotid artery stenosis with the right aortic arch.

Case Presentation: An 80-year-old man received medical treatment after experiencing left-sided cerebral infarction. He was admitted due to dysarthria and right hemiparesis. Magnetic resonance imaging revealed flesh infarctions in the left cerebral hemisphere and progression of left internal carotid artery stenosis. Computed tomography angiography showed right aortic arch with Kommerell diverticulum, and the first branch arising from the aortic arch was the left common carotid artery, followed by the right common carotid artery, right subclavian artery, and left subclavian artery. The origin of the left common carotid artery was significantly lower than the top of the aorta, and the aortic plaque was identified. Revascularization surgery of the left internal carotid artery stenosis was planned to prevent recurrent stroke, and carotid artery stenting was performed via the right brachial artery without any complications.

Conclusion: A preoperative neuroradiological imaging study that considers the approach route is necessary and useful for endovascular therapy.

Purpose: The presence of multiple dural arteriovenous fistulas (DAVFs) is rare; a high proportion show cortical venous reflux and often has associated neurological symptoms. We have experienced a case of DAVFs with four multiple shunts and an underlying metabolic disorder.

Case Presentation: A 65-year-old man with ocular symptoms and a gait disturbance had rapid neurological deterioration rapidly after hospitalization. Three shunts were found in the superior sagittal sinus and one in the transverse sinus, with marked cerebral venous congestion. Multiple transarterial embolizations and craniotomy surgery were performed, with a decrease in shunting and venous congestion. Hyperhomocystenemia (HHCY) was identified as a potential cause of the progressive DAVFs and associated severe neurological symptom.

Conclusion: HHCY may be associated with the occurrence and clinical course of DAVFs.

Objective: We report a case of the basilar artery occlusion treated with the mechanical thrombectomy through transradial approach.

Case presentation: A 73-year-old man caused the loss of consciousness and was taken to the hospital in an ambulance. The hyperdense sign was recognized at the top of the basilar artery (BA) on head CT. The angiogram showed occlusion of the right vertebral artery (VA) and severe stenosis of the left VA at the origin. In addition, left VA was markedly tortuous. We decided to perform the mechanical thrombectomy for BA embolism, following the angioplasty of the left VA via the left radial artery. Eventually, complete recanalization was achieved after the thrombectomy.

Conclusion: In mechanical thrombectomy, the time to reperfusion should be as short as possible. Transradial approach sometimes facilitates access to the posterior circulation.

Objective: In a dural arteriovenous fistula of the tentorium, varix formation and drainage into the great vein of Galen are considered as risk factors for hemorrhage. We encountered a case of dural arteriovenous fistula with unusual venous drainage routes. As such cases are rare, a detailed understanding of the structural features is necessary. We herein present a case along with a literature review.

Case presentation: A 73-year-old woman exhibited intracerebral and intraventricular hemorrhage. Findings of cerebral angiography led to the diagnosis of dural arteriovenous fistula of the falcotentorial junction. The shunt was located in the straight sinus, in proximity to the great vein of Galen, and retrograde flow into the supratentorial veins was also observed. Of the bilateral venous tributaries, the right tributary was connected via the longitudinal hippocampal vein to a varix in the basal ganglia. We performed endovascular embolization through the left middle meningeal and right occipital arteries, which were the feeders of the shunt, and achieved complete shunt occlusion.

Conclusion: We encountered a rare case of dural arteriovenous fistula of the falcotentorial junction with venous drainage routes located in the tentorium, of which the right tributary traveled through the longitudinal hippocampal vein. To identify the cause of the hemorrhage in the patient and develop an appropriate treatment strategy, a detailed understanding of the venous drainage routes and overall structure of the shunt was vital.