Physiologic Flow Diversion Coiling Technique for Wide-Necked Aneurysms with an Asymmetric Bidirectional Flow at the Aneurysm Neck

Purpose Wide-necked aneurysms in the circle of Willis (CoW) are prone to recur due to reciprocal bidirectional flow. We present a novel concept of coil embolization to prevent recurrence that uses physiologic flow diversion at the CoW. Materials and Methods We enrolled 14 patients (15 aneurysms) who underwent aneurysm coiling for wide-necked aneurysms with asymmetric bidirectional inflow into the aneurysm. Four patients had recurrent aneurysms after coiling. The concept of physiologic flow diversion included obliterating antegrade flow into the aneurysm sac as well as opposite CoW flow by performing compact coil packing with intentional protrusion out of the aneurysm neck to the communicating part. Results Fifteen aneurysms, including 4 recurrent aneurysms, in an anterior communicating artery (n=7), posterior communicating artery (n=5), and tip of the basilar artery (n=3) were treated with coil embolization (n=10) and stent-assisted coiling (n=5). All aneurysms had a wide neck, and the mean largest diameter was 9.0 mm. The mean packing density was 45.1%. Twelve aneurysms were completely occluded, and 3 aneurysms had tiny residual neck remnants. There was neither a neurological event nor recurrence during the mean 12.5 months of follow-up. Conclusion Wide-necked aneurysms at the CoW tend to recur. As a strategy to prevent a recurrence, physiologic flow diversion can be an option in treating wide-necked aneurysms in the CoW

Clinical Manifestation and Radiologic Patterns of Spontaneous Cervicocephalic Dissection According to the Anatomic Location: A Single-Center Analysis in Korean Patients

Purpose Spontaneous cervicocephalic dissection (SCAD) is an important cause of stroke and shows various lesion locations and clinical features. The purpose of this study was to analyze the location of SCAD and its clinical and radiologic patterns in Korean patients. Materials and Methods Patients with SCAD who were evaluated between 2013 and 2018 at a tertiary center in Korea were reviewed. We classified and compared the morphological (aneurysm or steno-occlusion) and presenting (hemorrhage or infarction) patterns according to the lesion locations (anterior circulation [AC] vs. posterior circulation [PC]; intradural [ID] vs. extradural [ED]). Results A total of 166 patients were included in this study. The SCAD most commonly occurred in the PC-ID location (65.1%), followed by AC-ID (13.3%), AC-ED (13.3%), and PC-ED (8.4%). Aneurysm and steno-occlusion patterns were observed in 66.9% and 57.8% of the cases, respectively. The aneurysm pattern was significantly more common in the PC-ID location (78.7%) than in other locations. As for the presenting pattern, cerebral infarction was the most common pattern (39.8%), and intracranial hemorrhage was observed only in the ID location (7.2%). Conclusion In Korean patients, PC-ID, especially ID vertebral artery, was the most common location of SCAD, and most cases were accompanied by an aneurysm. It also suggested that these location trends differ by population or ethnicity

Ruptured Medullary Hemangioblastoma Mimicking a Craniocervical Junction Dural Arteriovenous Fistula with a Pseudoaneurysm

Hemangioblastomas (HBMs) are rare vascular tumors commonly located in the posterior fossa of adults. A mid-50s patient presented with sudden unconsciousness. Computed tomography scans revealed acute hemorrhages around the posterior fossa, predominantly in the subarachnoid space. Digital subtraction angiography (DSA) revealed an 8-mm round lesion filled with contrast agent, fed by the C1 segmental artery of the left vertebral artery (VA), showing early venous drainage to the spinal cord and brainstem. Emergent embolization was attempted under suspicion of a ruptured dural arteriovenous fistula, resulting in parent artery occlusion due to feeder selection failure. Follow-up DSA after a month depicted a persistent aneurysm via collaterals from both VAs. Consequently, the decision was made to proceed with surgical intervention, leading to the resection of the lesion, confirming its diagnosis as a HBM through histological examination. This case underscores the potential for misdiagnosis when HBMs with an intratumoral shunt mimic vascular shunt lesions

Safety and Effectiveness of the Novel Catheter 3.0 System for Diagnostic Cerebral Angiography: A Pilot Study

Purpose The purpose of this study was to evaluate the safety and effectiveness of a new angiographic system (Catheter 3.0 system) using a 5 French (Fr), large-bore angiography catheter, a 0.032-inch stiff guidewire, and a continuous flushing system in diagnostic cerebral angiography. Materials and Methods This retrospective study included 30 consecutive patients who underwent transfemoral cerebral angiography using the Catheter 3.0 system from October 2019 to March 2020. As the control group, we included 30 consecutive patients examined before the Catheter 3.0 system was introduced. Procedural outcomes, including technical success, procedure time, dose metrics, procedure-related complications, and image quality were reviewed and analyzed. Results All transfemoral cerebral angiographies were performed for a diagnosis of unruptured intracranial aneurysms. The Catheter 3.0 system showed a significantly shorter fluoroscopy time (6.2 vs. 9.7 minutes, P=0.008) and lower fluoroscopy dose (387.2 vs. 614.4, P=0.002) compared with the conventional 4-Fr catheter system. The Catheter 3.0 system also showed better results in terms of procedural time (21.0 vs. 22.5 minutes, P=0.072) and technical success rate (98.1% vs. 94.0%, P=0.078), although a statistical significance was not reached. The complication rate and qualitative assessment of the digital subtraction angiography (DSA) image quality were similar between the two groups. Conclusion The Catheter 3.0 system using a 5 Fr catheter with a large inner diameter was convenient, effective, and safe compared with the conventional system in diagnostic cerebrovascular angiography

Endovascular Treatment of Arterial Steno-Occlusive Lesions in Symptomatic Moyamoya Disease

The efficacy and safety of endovascular treatment (EVT) for moyamoya disease (MMD) have rarely been investigated. The objective of this study was to summarize the clinical outcomes of EVT for MMD and determine the potential role of EVT in treating symptomatic steno-occlusive lesions in MMD. Reports from January 2000 to December 2021 describing EVT in MMD were collected through a literature search. The search terms included “moyamoya”, “stent”, “angioplasty”, and “endovascular”. Data regarding baseline demographics, previous medical history, treated vessel, periprocedural complications, and angiographical recurrence were retrieved. This review included 10 studies with details of 19 patients undergoing a total of 31 EVT procedures. Twenty-one EVTs were performed as initial treatments for MMD, and 10 were performed as additional treatments for angiographical recurrence. The mean follow-up period of the initial EVTs was 9.0±11.9 months, with angiographical recurrence in 11 (68.8%) cases. The mean follow-up period of additional EVTs was 4.3±3.9 months, and seven (70.0%) EVTs showed restenosis of the re-treated vessel. Across all initial and additional EVTs, there were no differences in characteristics between the recurrence and non-recurrence groups. Overall, two periprocedural complications (9.5%) occurred, one vessel rupture and one massive intracerebral hemorrhage with subarachnoid hemorrhage. EVT plays a limited role in the management of symptomatic intracranial arterial steno-occlusive lesions of MMD. Recent advances in understanding the pathomechanism of MMD may urge neuro-interventionists to find a new endovascular approach with better balloon angioplasty or stenting mechanisms

Facilitated Retrograde Access the Facial Vein for Transvenous Embolization of the Cavernous Sinus Dural Arteriovenous Fistula with Isolated Ophthalmic Venous Drainage

Management of cavernous sinus dural arteriovenous fistula (CSDAVF) continues to present significant challenges, particularly when the inferior petrosal sinus is thrombosed, collapsed, or angiographically invisible. In this study, we introduce facilitated retrograde access via the facial vein, which is employed in the transvenous embolization of CSDAVF with isolated superior ophthalmic venous drainage. We also present illustrative cases and technical points

Embolization Tactics of Spinal Epidural Arteriovenous Fistulas

Purpose Spinal epidural arteriovenous fistulas (SEDAVFs) show an epidural venous sac often with venous congestive myelopathy (VCM) due to intradural reflux at a remote level to which a transarterial approach would be difficult. We present 12 cases of SEDAVF with VCM and describe 3 main tactics for effective transarterial embolization. Materials and Methods Among 152 patients with spinal vascular malformations diagnosed in our tertiary hospital between 1993 and 2019, 12 SEDAVF patients with VCM were included. Three different transarterial embolization tactics were applied according to the vascular configuration and microcatheter accessibility. We evaluated treatment results and clinical outcomes before and after treatment. Results Transarterial embolization with glue (20–30%) was performed in all patients. The embolization tactics applied in 12 patients were preferential flow (n=2), plug-and-push (n=6), and filling of the venous sac (n=4). Total occlusion of the SEDAVF, including intradural reflux, was achieved in 11 (91.7%) of 12 patients, and partial occlusion was achieved in 1 patient. No periprocedural complications were reported. Spinal cord edema was improved in all patients for an average of 18 months after treatment. Clinical functional outcome in terms of the pain, sensory, motor, and sphincter scale and modified Rankin scores improved during a mean 25-month follow-up (6.3 vs. 3.3, P=0.002; 3.6 vs. 2.3, P=0.002, respectively). Conclusion Endovascular treatment for 12 SEDAVF patients with VCM achieved a total occlusion rate of 91.7% without any periprocedural complication. The combined embolization tactics can block intradural reflux causing VCM, resulting in overall good clinical outcomes

Highly Enhanced Photoactivity of Anatase TiO₂ Nanocrystals by Controlled Hydrogenation-Induced Surface Defects

Anatase TiO₂ nanocrystals (aTiO₂) of a uniform size have been synthesized and were subject to a successive hydrogenation under a H₂ gas flow at elevated temperatures (500–700 °C). We found that the concentration of Ti³⁺ defects, such as Ti³⁺ interstitials and oxygen vacancies, and their distribution between surface and bulk varied significantly, depending on the hydrogenation temperature and time. Such changes in defects were found to be critical in enhancing the photoactivity of the hydrogenated TiO₂ (H-aTiO₂) by an order of magnitude. In our case, H-aTiO₂ nanocrystals hydrogenated at 600 °C for longer than 10 h showed 10 times higher photoactivity than aTiO₂, which was explained from a high surface-to-bulk defect ratio and a nonuniform distribution of defects between bulk and surface due to a preferential diffusion of bulk defects to the surface. Our study showed that a kinetically controlled hydrogenation condition could be used not only to control the surface/bulk defects but also to enhance the photoactivity of oxide nanocrystals

Microcatheter Stabilization Technique Using Partially Inflated Balloon for Coil Embolization of Paraclinoid Aneurysms

Purpose Coil embolization of paraclinoid aneurysms should be simple, safe, and effective considering the benign nature of the aneurysm. Here, we present a microcatheter stabilization technique using a partially inflated balloon for the treatment of paraclinoid aneurysms. Materials and Methods This retrospective study included 58 patients who underwent balloon-assisted coiling (BAC) for unruptured paraclinoid aneurysms at a tertiary neuro-intervention center between January 2019 and March 2020. We applied a technique to stabilize the microcatheter’s position using the modified BAC technique in paraclinoid aneurysms showing various projections around the ophthalmic curve of the internal carotid artery. The basic concept of the technique is to place a partially inflated balloon just distal to the aneurysm neck and support the distal curve of the microcatheter using the proximal bottom of the balloon. Immediate radiological outcomes were analyzed, and clinical outcomes were evaluated with modified Rankin Scale (mRS) scores. Results The BAC was successfully performed in 51 of 58 patients (88%). We treated the remaining 7 patients by switching to stent-assisted coiling. We obtained a 37% mean packing density resulting in favorable occlusion in all 58 aneurysms (complete occlusion in 35 and residual neck in 23). There were no intraprocedural thromboembolic or hemorrhagic events except one that revealed an asymptomatic infarction after the procedure (1.7%). Magnetic resonance angiography follow-up was performed in 37 patients at an average of 11.8 months, in which 11 minor recurrences (29.7%) were found. There was no major recurrence nor retreatment. The mRS score was 0 in all patients during a mean follow-up of 17.7 months (range, 12–25 months). Conclusion The modified balloon-assisted coiling technique using a partially inflated balloon was safe and effective and could serve as an option for treating paraclinoid aneurysms