UNASSIGNED: Distal posterior inferior cerebellar artery (PICA) aneurysms are exceedingly rare intracranial aneurysms. In the acute phase of rupture, interventions commonly involve parent artery occlusion through endovascular treatment or direct trapping surgery. There is no consensus on the best treatment of chronic ruptured or unruptured aneurysms, and stent-assisted coil embolization has not yet been reported in the chronic phase of rupture.
UNASSIGNED: We present a case of a 46-year-old female with a recurrent distal PICA aneurysm at 18 months following the initial treatment for subarachnoid hemorrhage and was treated by stent-assisted coil embolization with Neuroform Atlas (Stryker, USA), with a favorable outcome.
UNASSIGNED: Distal PICA aneurysms occur at the apical curvature, where primitive arterial anastomoses existed during development, pointing to the potential vulnerability of the vessel wall at these sites. Stent-assisted coil embolization has shown effectiveness in preserving the parent artery for chronic ruptured and unruptured distal PICA aneurysms. Nonetheless, the narrowness and tortuosity of the PICA present obstacles to treatment. In our case, the procedure was feasible utilizing the Neuroform Atlas (Stryker, USA) with the Transcell approach. A thorough grasp of the characteristics of stents and their application is pivotal for achieving effective treatment outcomes.

UNASSIGNED: Subarachnoid hemorrhage (SAH) due to blood blister-like aneurysm (BBA) is rare but very risky during treatment. Moreover, there is no established treatment method. In this study, we performed endovascular treatment (EVT) as the first-line treatment on patients with SAH during the subacute phase, and cases were analyzed in this series.
UNASSIGNED: Patients with SAH due to BBA who visited our hospital between April 2021 and March 2023 were enrolled in this study. We waited as long as possible during the acute phase and performed EVT during the subacute phase. We performed stent-assisted coiling (SAC) as the first-line treatment and performed DSA approximately 6 months after treatment.
UNASSIGNED: Ninety-six patients with SAH visited our hospital during the study period and six had SAH due to BBAs. There were two males and four females aged 56.2 ± 14.6 years. We performed SAC in five patients, and one died owing to rebleeding before treatment. Two patients received treatments because of rebleeding. One patient died on the day after rebleeding, whereas the other experienced rebleeding and treatments twice and achieved a good outcome. Four patients had good outcomes (modified Rankin scale [mRS]: 0). The surviving patients achieved complete occlusion at follow-up DSA. However, two patients had poor outcomes (mRS: 6).
UNASSIGNED: Patients with SAH due to BBA treated in the subacute phase may achieve good outcomes; however, there is a risk of rebleeding during the waiting period, which often causes poor outcomes.

UNASSIGNED: To report the rare case of a patient with a perianeurysmal cyst following stent-assisted coil embolization of an unruptured vertebral artery aneurysm.
UNASSIGNED: A 63-year-old woman underwent stent-assisted coil embolization for an unruptured vertebral artery aneurysm embedded in the brainstem (pons). Complete occlusion of the aneurysm was successfully achieved. However, subsequent magnetic resonance imaging (MRI) conducted 8 months after the procedure showed perilesional edematous changes surrounding the aneurysm, and at 20 months, cyst formation was observed in the vicinity of the aneurysm. Progressive enlargement of the cyst eventually led to the development of paralysis and dysphagia, necessitating cyst fenestration surgery. Although postoperative reduction in the cyst size was achieved, the patient experienced complications in the form of aspiration pneumonia and bacterial meningitis, which resulted in a life-threatening condition.
UNASSIGNED: Aneurysms embedded in the brain parenchyma should be carefully followed up, recognizing the risk of perianeurysmal cyst formation after coil embolization.

UNASSIGNED: Stents have been widely used for coil embolization for intracranial aneurysms. Few studies have analyzed the risk factors of recanalization through long-term follow-up observation of only stent-assisted coiling. We analyzed the risk factors for recanalization through long-term observations.
UNASSIGNED: A total number of 399 unruptured aneurysms treated by stent-assisted coil embolization between 2003 and 2016 in a single institution were analyzed for determining the factors associated with recanalization including the patient characteristics, aneurysms, and procedural variables. All patients underwent angiographic follow-up with digital subtraction angiography or magnetic resonance angiography at 24 months or more following the procedure.
UNASSIGNED: Recanalization occurred in 8%. The mean time for the recanalization was 21.1 ± 14.0 months (range, 5-51 months). The receiver operating characteristic curve analysis indicated areas under the curve for a maximum aneurysm size of 0.773 (cut-off, 6.415 mm). Multivariate analysis revealed that the maximum aneurysm size and parent artery curvature at which the aneurysm developed were significantly associated with recanalization. In parent artery curvature, the bifurcation group (OR, 9.02; 95% CI, 2.53-32.13; p = 0.001) and the convex group (OR, 3.68; 95% CI, 1.17-11.50; p = 0.025) were independent predictors of recanalization compared with the straight group.
UNASSIGNED: The maximum aneurysm size and parent artery curvature are risk factors associated with recanalization in stent-assisted coil embolization.

OBJECTIVE: Although stent-assisted technique is expected to help provide a scaffold for neointima formation at the orifice of the aneurysm, not all aneurysms treated with stent-assisted technique develop complete neointima formation. The white-collar sign (WCS) indicates neointimal tissue formation at the aneurysm neck that prevents aneurysm recanalization. The aim of this study was to explore factors related to WCS appearance after stent-assisted coil embolization of unruptured intracranial aneurysms (UIAs).
METHODS: A total of 59 UIAs treated with a Neuroform Atlas stent were retrospectively analyzed. The WCS was identified on digital subtraction angiography (DSA) 1 year after coil embolization. The cohort was divided into WCS-positive and WCS-negative groups, and possible predictors of the WCS were explored using logistic regression analysis.
RESULTS: The WCS appeared in 20 aneurysms (33.9%). In the WCS-positive group, neck size was significantly smaller (4.2 (interquartile range (IQR): 3.8-4.6) versus 5.4 (IQR: 4.2-6.8) mm, p = .006), the VER was significantly higher (31.8% (IQR: 28.6%-38.4%) versus 27.6% (IQR: 23.6%-33.8%), p = .02), and the rate of RROC class 1 immediately after treatment was significantly higher (70% vs 20.5%, p < .001) than in the WCS-negative group. On multivariate analysis, neck size (odds ratio (OR): 0.542, 95% confidence interval (CI): 0.308-0.954; p = .03) and RROC class 1 immediately after treatment (OR: 6.99, 95% CI: 1.769-27.55; p = .006) were independent predictors of WCS appearance.
CONCLUSIONS: Smaller neck size and complete occlusion immediately after treatment were significant factors related to WCS appearance in stent-assisted coil embolization for UIAs using the Neuroform Atlas stent.

UNASSIGNED: Stent-assisted coil (SAC) embolization is a commonly used endovascular treatment for unruptured intracranial aneurysms (UIAs) but can be associated with symptomatic delayed intracerebral hemorrhage (DICH). Our study aimed to investigate the hemodynamic risk factors contributing to DICH following SAC embolization and to establish a classification for DICH predicated on hemodynamic profiles.
UNASSIGNED: This retrospective study included patients with UIAs located in the internal carotid artery (ICA) treated with SAC embolization at our institution from January 2021 to January 2022. We focused on eight patients who developed postoperative DICH and matched them with sixteen control patients without DICH. Using computational fluid dynamics, we evaluated the hemodynamic changes in distal arteries [terminal ICA, the anterior cerebral artery (ACA), and middle cerebral artery (MCA)] pre-and post-embolization. We distinguished DICH-related arteries from unrelated ones (ACA or MCA) and compared their hemodynamic alterations. An imbalance index, quantifying the differential in flow velocity changes between ACA and MCA post-embolization, was employed to gauge the flow distribution in distal arteries was used to assess distal arterial flow distribution.
UNASSIGNED: We identified two types of DICH based on postoperative flow alterations. In type 1, there was a significant lower in the mean velocity increase rate of the DICH-related artery compared to the unrelated artery (-47.25 ± 3.88% vs. 42.85 ± 3.03%; p < 0.001), whereas, in type 2, there was a notable higher (110.58 ± 9.42% vs. 17.60 ± 4.69%; p < 0.001). Both DICH types demonstrated a higher imbalance index than the control group, suggesting an association between altered distal arterial blood flow distribution and DICH occurrence.
UNASSIGNED: DICH in SAC-treated UIAs can manifest as either a lower (type 1) or higher (type 2) in the rate of velocity in DICH-related arteries. An imbalance in distal arterial blood flow distribution appears to be a significant factor in DICH development.

UNASSIGNED: Dissecting aneurysms of the middle cerebral artery (MCA) are very rare. We herein report a case of an unruptured dissecting aneurysm of the MCA treated by stent-assisted coil embolization.
UNASSIGNED: A 65-year-old man with no history of trauma presented with a headache. Time-of-flight imaging revealed a dissecting cerebral aneurysm in the right M1 segment of the MCA, and the aneurysm had increased in size within a short time. We treated the aneurysm by endovascular stenting with coils, and the patient developed no neurological deficits.
UNASSIGNED: Because of the potential involvement of the lenticulostriate artery (LSA) in the area of dissection, choosing the best treatment (such as direct surgery or endovascular treatment) may be challenging. Treatment efficacy depends on whether the LSA is affected and on the length of the dissection. In our case, the dissection did not involve the LSA and could therefore be treated by stent-assisted coil embolization.

UNASSIGNED: In the acute stage of ruptured cerebral aneurysms, limited devices are available, making the treatment difficult. We aimed to evaluate the outcomes of the coil embolization with stenting for the ruptured cerebral aneurysms in the acute stage.
UNASSIGNED: We assessed 22 cases treated with stenting among 134 of 169 consecutive patients with subarachnoid hemorrhages undergoing an endovascular treatment between April 2014 and December 2021, of which 134 underwent an embolization during the acute stage. A stent was used in the patients wherein the treatment with the balloon-assisted or double catheter technique was difficult. Stenting was performed under the loading of two or more antiplatelet agents.
UNASSIGNED: The mean age of the patients was 68.9 years, of which five were male and 14 (63.6%) had severe grade (World Federation of Neurosurgeons grade IV, V). The aneurysm site was the anterior communicating artery in four cases, internal carotid artery in nine, middle cerebral artery in two, vertebrobasilar artery in six, and posterior cerebral artery in one. The aneurysm shape was saccular in 13 cases, dissection in seven, and fusiform in two. Stents were used for wide-neck aneurysms in 12 cases, vascular preservation in seven, and rescue in three. The mean maximum diameter was 9.6 mm. The mean neck size was 6.4 mm. Complete occlusion and neck remnant were found in eight and seven cases, respectively. The perioperative complication rate was 45.5% (thromboembolism in five cases, stent occlusion in two, re-bleeding in two, and cerebral hemorrhage in one). The outcomes included modified Rankin Scale 0-2 in seven cases, 4-5 in five, and 6 in nine. Stent-related death occurred in one case. The rate of morbidity and mortality was 18.2%. Although stents were used in the acute stage of rupture, they were used for the right reasons. However, a high rate of complications occurred: two cases of re-bleeding, in which an incomplete occlusion was a factor.
UNASSIGNED: Stent placement in patients with the acute ruptured cerebral aneurysms should be carefully determined and efforts should be made to reduce the embolic and hemorrhagic complications. However, it may be an effective treatment option when other options could be extremely difficult.

UNASSIGNED: Stent-assisted coil (SAC) is increasingly used to treat unruptured intracranial aneurysm (UIA). However, the optimal duration of dual-antiplatelet therapy (DAPT) after SAC insertion remains unknown.
UNASSIGNED: To assess the time-dependent effect of DAPT on the risk of ischemic and hemorrhagic complications after SAC.
UNASSIGNED: This is a retrospective cohort study among patients with UIA treated with SAC using the nationwide health claims database in South Korea between 2009 and 2020. Multivariate Cox regression analysis was used, which included the use of DAPT as a time-dependent variable. The effect of DAPT was investigated for each period of \"within 90 days,\" \"91 to 180 days,\" \"181 to 365 days,\" and \"366 to 730 days\" after SAC. The primary outcome was a composite of ischemic stroke and major bleeding in each period within two years after SAC.
UNASSIGNED: Of the 15,918 patients, mean age at SAC was 57.6 ± 10.8 years, and 3815 (24.0%) were men. The proportion of patients on DAPT was 79.4% at 90 days, 58.3% at 180 days, and 28.9% at 1 year after SAC. During the 2 years after SAC, the primary composite outcome occurred in 356 patients (2.2%). DAPT significantly reduced the primary composite outcome within 90 days after SAC (adjusted hazard ratio (aHR), 0.44; 95% confidence interval (CI), 0.28-0.69; p < 0.001); however, this was not the case after 90 days (all p > 0.05). DAPT reduced ischemic stroke risk within 90 days (aHR, 0.31; 95% CI 0.18-0.54; p < 0.001), and 91 to 180 days after SAC (aHR 0.40; 95% CI 0.18-0.88; p = 0.022); however, after 180 days, DAPT was no longer beneficial.
UNASSIGNED: In patients with UIA treated with SAC, 3 months of DAPT was associated with a decreased risk of the composite of ischemic and hemorrhagic complications.

UNASSIGNED: Image evaluation after stent-assisted coil embolization (SAC) for a cerebral aneurysm is difficult with conventional MRA or CTA because of metal artifacts. Pointwise encoding time reduction with radial acquisition (PETRA)-MRA is a noninvasive imaging examination that can reduce metal artifacts. This study aimed to examine whether PETRA-MRA can be used as a follow-up imaging after SAC.
UNASSIGNED: Twelve patients (eight women and four men; mean age, 66.9 ± 13.2 years) underwent SAC for unruptured aneurysms and were retrospectively evaluated using time-of-flight (TOF)- and PETRA-MRA data from the same follow-up session. Two neurosurgeons independently compared the aneurysm occlusion status and flow visualization score in the stented parent artery (4-point scale, where 4 points represented excellent visualization) between TOF- and PETRA-MRA images. If DSA was performed within 3 months before or after PETRA-MRA, the aneurysm assessment was compared between MRA and DSA. The interobserver agreement for each MRA was evaluated.
UNASSIGNED: Nine of the 12 patients underwent DSA within 3 months before and after TOF- and PETRA-MRA. The aneurysm occlusion status on DSA was more consistent with PETRA-MRA (eight of nine cases) than with TOF-MRA (one of nine cases; P = 0.023). The median visualization score of the stented parent artery was significantly higher for PETRA-MRA (4 [interquartile range {IQR} 3-4]) than for TOF-MRA (1 [IQR 1-1], P = 0.003). The interobserver agreement for evaluation of the aneurysm occlusion status and visualization score of the parent artery for PETRA-MRA were excellent (κ = 0.98 and 0.93, respectively). In one case, PETRA-MRA was able to detect aneurysm recurrence, leading to subsequent retreatment.
UNASSIGNED: PETRA-MRA is a noninvasive examination that can be used to evaluate the occlusion status of aneurysms after SAC and visualize the stented parent artery. PETRA-MRA is useful for repeated follow-up examinations after SAC.