Objective: Although embolization of cerebral arteriovenous malformations (AVM) is widely performed as an adjunctive therapy before microsurgery or radiosurgery, there is no high-level evidence to ascertain its effectiveness. However, the technology for endovascular devices has improved. Therefore, this study aimed to identify the chronological changes in AVM embolization due to advances in endovascular treatment devices.

Methods: This retrospective study included 24 patients who underwent 31 embolization procedures between January 2018 and August 2023. Embolization plus microsurgery, embolization plus radiosurgery, and embolization alone were performed in 15 (62.5%) patients and 21 embolization procedures, 2 (8.3%) patients and 2 procedures, and 7 (29.2%) patients and 8 procedures, respectively. We assessed chronological changes in endovascular treatment devices and evaluated clinical outcomes (ideal position of microcatheter, vessel perforations, symptomatic complications) from January 2018 to December 2020 and from January 2021 to August 2023 based on the chronological changes in endovascular treatment devices.

Results: Intermediate catheters were employed in 29 (93.5%) procedures. Brands of intermediate catheters and microcatheters significantly changed around 2021. No differences were observed in the embolic materials. The ideal position of the microcatheter was achieved significantly more in 2021–2023 than in 2018–2020 (72.1% vs. 48.4%, p = 0.04). Vessel perforation by microcatheters in 2018–2020 and 2021–2023 occurred in 3 (18.8%) and 1 (6.7%) procedures (p = 0.32), respectively. Symptomatic complications in 2018–2020 and 2021–2023 occurred in 3 (18.8%) and 0 (p = 0.08) procedures, respectively. Complete obliteration was achieved in 18 of 24 patients (75.0%). Favorable clinical outcomes (modified Rankin Scale score 0–2) were observed in 20 of 24 (83.3%) patients at the final follow-up.

Conclusion: The advancement in endovascular devices for AVM has enabled effective and safe embolization, potentially enhancing the outcomes of microsurgical interventions.

Objective: Contrast-induced encephalopathy (CIE) is a rare but severe complication that can occur following intravascular treatment of intracranial vascular disease. Although CIE is considered a transient neurological disorder, its natural history, pathophysiology, and risk factors are poorly understood. Contrast leakage (CL) is a more frequently observed adverse event than CIE and can lead to CIE. This retrospective study aimed to elucidate the clinical characteristics of CL and CIE and identify the risk factors for each.

Methods: We retrospectively reviewed the medical records of 61 patients with unruptured intracranial aneurysms who were treated at our institution between January 2019 and May 2023. Risk factors for CIE and CL were identified by Fisher’s exact test for univariate analysis of categorical variables and by unpaired t-test for continuous variables. One-way analysis of variance (ANOVA) was conducted, followed by the Tukey-Kramer test for multiple comparisons.

Results: Of the 61 patients, 22 (36%) had CL and 4 (6%) had CIE. Among the clinical characteristics analyzed, older age (p = 0.031), larger aneurysm (p = 0.003), lower serum creatinine (p = 0.026), and use of a distal access catheter (p = 0.030) were significant risk factors for CL. CIE occurred only in CL-positive patients (p = 0.014). Of the 4 patients with CIE, neurological symptoms improved within 3 days in 3 patients, and neurological deficit persisted in 1 patient.

Conclusion: Older age, larger aneurysm, lower serum creatinine, and use of a distal access catheter are risk factors for developing CL, and female sex and greater volume of contrast medium are potential risk factors. No risk factors for developing CIE from CL were identified.

Objective: Prehension of the position of the microcatheter tip under fluoroscopy during cerebral aneurysm embolization is critical to prevent intraoperative rupture of the aneurysm, even if the first marker at the tip is obscured by coils in the aneurysm. This study presents our initial experience with a sub-marker catheter, which includes an additional marker positioned 5 mm from the tip, designed to facilitate accurate positioning of the microcatheter tip.

Methods: We analyzed cases of cerebral aneurysms treated with sub-marker catheters at our hospital from July 2022 to September 2023. Single catheter embolization served as the primary treatment option, with balloon-assisted or stent-assisted techniques utilized only when necessary.

Results: During the study period, 18 patients with cerebral aneurysms were treated using sub-marker catheters. The median age of these patients was 65 years, comprising 8 men and 10 women. The aneurysms had a median maximum diameter of 6.2 mm, ranging from 5.0 to 16.8 mm. Among the 18 treated patients, 14 had unruptured aneurysms and 4 had ruptured aneurysms. Treatment methods included single catheter embolization in 10 patients, double catheter embolization in 3, stent-assisted embolization in 3, balloon-assisted embolization in 1, and flow diverter placement combined with coil embolization in 1. The sub-marker was consistently visible under fluoroscopy, aiding the precise positioning of the microcatheter tip without interference from the coils. No complications occurred, and successful embolization was achieved in all cases.

Conclusion: The sub-marker catheter appears valuable for safely performing aneurysm embolization.

Objective: We describe two cases of myelopathy onset due to intracranial dural arteriovenous fistulas (DAVFs) and present a literature review.

Case Presentation: (Case 1) A 44-year-old man with subacute onset myelopathy underwent an MRI and DSA. MRI showed T2-hyperintensity from the medulla oblongata to the cervical spinal cord with vascular flow voids, suggestive of a spinal DAVF. Unexpectedly, cerebral angiography revealed a tentorial DAVF. (Case 2) A 47-year-old man with progressive myelopathy underwent a head and spinal MRI. Head MRI and MRA were considered to be normal. Spinal MRI revealed T2-hyperintensity in the cervical spinal cord without obvious vascular flow voids around the spinal cord. Contrast-enhanced MRI showed a patchy gadolinium enhancement in the same spinal cord region with the enhancement of perimedullary vessels. Although myelitis was initially suspected, subsequently spinal DAVF was suspected because cervical CTA revealed abnormal spinal venous drainage. Unexpectedly, cerebral angiography identified a foramen magnum DAVF.

Conclusion: Regarding unexplained cervical myelopathy, even the absence of spinal cord surface vascular flow voids cannot necessarily exclude venous congestive myelopathy due to the DAVFs. In such cases, the contrast-enhanced MRI and cervical CTA are useful for visualizing abnormal vessels around the brain stem and the cervical spine. Especially, the co-presence of the abnormal vessels around the brain stem can suggest the intracranial DAVFs. Not only spinal DAVFs but also intracranial DAVFs should be considered as the differential diagnoses for venous congestive cervical myelopathy, in which cases cerebral angiography including carotid angiography is essential.