Case report: isolated trochlear nerve palsy associated with posterior cerebral artery aneurysm.

We describe a case of isolated trochlear nerve palsy caused by an unruptured posterior cerebral artery (PCA) aneurysm in an 82-year-old male who consulted an ophthalmologist after developing diplopia. Magnetic resonance angiography showed a left PCA aneurysm in the ambient cistern, and T2WI showed an aneurysm compressing the left trochlear nerve to the cerebellar tentorium. Digital subtraction angiography revealed that the lesion was located between the left P2a segment. We attributed this isolated trochlear palsy to left PCA unruptured aneurysm pressure. Thus, we performed stent-assisted coil embolization. The aneurysm was obliterated, and trochlear nerve palsy improved completely.

Added Value of Selective Intra-arterial Cone-Beam CT Angiography in the Management of Visceral Artery Aneurysms.

PURPOSE: The aim of this study is to evaluate the value of selective intra-arterial cone-beam computed tomography angiography (CBCTA) relative to conventional computed tomography angiography (CTA) in understanding visceral artery aneurysm (VAA) morphology, and its impact on treatment planning. MATERIALS AND METHODS: Between January 2017 and August 2021, all patients who had a diagnosis of VAA and underwent intraoperative CBCTA imaging were retrospectively reviewed. Impact on treatment decisions, optimal C-arm angulations derived from CBCTA, and additional radiation exposure were reported. Two blinded independent reviewers qualitatively reviewed CBCTA and conventional CTA images. A 5-point Likert scale (1=poor image quality, 5=excellent image quality) was used to assess the overall image quality of each modality. Number of vessels arising from the aneurysm sac was counted. RESULTS: A total of 16 patients had a diagnosis of VAA during the study period, of whom 10 patients had intraoperative CBCTA and conventional CTA available for review. Out of 10 patients, 7 underwent successful endovascular treatment, 2 were deemed not amenable for endovascular embolization based on intraoperative CBCTA findings, and 1 had resolved pseudoaneurysm. Total fluoroscopy time and radiation dose (dose area product [DAP] and skin dose) for all procedures were 27.7 ± 19.9 minutes, 28 362 (±18 651) µGy*m2, and 1879 (±1734) mGy, respectively. Radiation exposure from CBCTA (DAP and skin dose) was 5703 (±3967) µGy*m2 and 223.6 (±141.3) mGy, respectively. In patients who underwent endovascular treatment, the proportional DAP from CBCTA was 18.3% (±15.3%) of the total procedural radiation dose. Qualitative rating of overall image quality of CBCTA images was superior to CTA images (mean score: 4.55 vs 3, p<0.001). More branch vessels arising from the VAA were identified by all reviewers in CBCTA as compared with conventional CTA (median, min-max: 3, 0-4 vs 2,1-3 vessels). CONCLUSION: Intraoperative CBCTA after selective intra-arterial contrast injection, with better spatial resolution, provided better delineation of visceral aneurysm morphology as compared with conventional, intravenous CTA and enabled optimal treatment planning at a reasonable additional radiation exposure. CLINICAL IMPACT: Visceral artery aneurysms (VAA) are often diagnosed incidentally by conventional computed tomographic angiography (CTA). Endovascular treatment typically requires selective angiographies at multiple projections to better understand aneurysm morphology, location, and efferent branch vessels. Intra-arterial cone-beam CT angiography (CBCTA) for VAA has the advantage of selective contrast opacification, better spatial resolution, and three-dimensional/multi-planar visualization of aneurysm morphology. In addition, CBCTA enables identification of optimal C-arm working projection for subsequent endovascular treatment. The aim of this study is to evaluate the value of intraoperative CBCTA relative to conventional CTA in understanding visceral artery aneurysm morphology and its impact on treatment planning.

Metal artifact reduction algorithm for image quality improvement of cone-beam CT images of medium or large cerebral aneurysms treated with stent-assisted coil embolization.

PURPOSE: The aim of the present study was to assess image quality improvement using a metal artifact reduction (MAR) algorithm in cases of medium or large cerebral aneurysms treated with stent-assisted coil embolization (SAC), and to analyze factors associated with the usefulness of the MAR algorithm. METHODS: We retrospectively evaluated the cone-beam computed tomography (CBCT) data sets of 18 patients with cerebral aneurysms treated with SAC. For subjective analysis, images of all cases with and without MAR processing were evaluated by five neurosurgeons based on four criteria using a five-point scale. For objective analysis, the CT values of all cases with and without MAR processing were calculated. In addition, we assessed factors associated with the usefulness of the MAR by analyzing the nine cases in which the median score for criterion 1 improved by more than two points. RESULTS: MAR processing improved the median scores for all four criteria in 17/18 cases (94.4%). Mean CT values of the region of interest at the site influenced by metal artifacts were significantly reduced after MAR processing. The maximum diameter of the coil mass (< 17 mm; odds ratio [OR], 4.0; 95% confidence interval [CI], 1.2-13.9; p = 0.02) and vessel length covered by metal artifacts (< 24 mm; OR, 2.3; 95% CI, 1.1-4.7; p = 0.03) was significantly associated with the usefulness of the MAR. CONCLUSIONS: This study suggests the feasibility of a MAR algorithm to improve the image quality of CBCT images in patients who have undergone SAC for medium or large aneurysms.

Stent-assisted coil embolization of MCA aneurysm via a trans-posterior communicating artery access.

External carotid artery (ECA) to internal carotid artery (ICA) bypass is a well-established procedure for the treatment of chronic ischemic diseases of the carotid artery. Rarely de novo aneurysms can develop at the site of anastomosis. The treatment of these aneurysms can be very challenging due to various factors, including the presence of graft, previous craniotomy, atherosclerotic vessels, and lack of direct access. In this video the authors report and discuss the management of a right middle cerebral artery (MCA) wide-necked de novo aneurysm by stent-assisted coiling through a retrograde trans-posterior communicating artery access.The video can be found here: https://youtu.be/MBKolPvOErU.

De novo vertebral artery dissecting aneurysm after internal trapping of the contralateral vertebral artery.

We present the case of a de novo vertebral artery dissecting aneurysm (VADA) after endovascular trapping of a ruptured VADA on the contralateral side. The first ruptured VADA involved the posterior inferior cerebellar artery, which was successfully treated by endovascular internal trapping using a stent. A follow-up study at 3 months revealed a de novo VADA on the contralateral side. The second VADA was successfully embolized using coils while normal arterial flow in the vertebral artery was preserved using a stent. Increased hemodynamic stress may cause the development of a de novo VADA on the contralateral side.

Stent-assisted coil embolization of challenging intracranial aneurysms: initial and mid-term results with low-profile ACCLINO devices.

BACKGROUND: Stent-assisted coiling using low-profile, self-expandable and retrievable stents is a valid option in endovascular treatment of challenging intracranial aneurysms. This study aims to evaluate the feasibility and efficacy of ACCLINO 1.9 F and ACCLINO Flex stent systems, designed for use as adjunctive products in coil embolization of intracranial aneurysms. METHODS: Case files of 47 patients, and 52 aneurysms in total, treated with at least one ACCLINO 1.9 F or ACCLINO Flex stent were retrospectively evaluated. Technical success, complications, and angiographic outcomes were assessed based on immediate post-procedural controls along with 6th and 12th month angiograms. RESULTS: Mechanical untoward event rate, including asymptomatic complications, is 9.6 % (five out of 52 aneurysms). Failed dual-stenting attempt rate is 15.4 % (two out of 13). Overall procedure-related morbidity is 4.2 % with no neurologic sequelae. Initial occlusion rate is 90.4 % (47 aneurysms). One patient had residual filling in the aneurysm neck, which was stable throughout follow-up. The remaining four cases had spontaneous follow-up occlusion. Recanalization rate at 6th month is 2.1 % with one aneurysm requiring retreatment. One patient was lost to follow-up. There is no mortality associated with treatment. CONCLUSIONS: Stent-assisted coil embolization with ACCLINO stents in single or dual configurations is a feasible treatment option for challenging intracranial aneurysms. Follow-up results are encouraging; techniques were effective in complex cases and there were no clinically significant adverse outcomes.

In vitro experiments of vessel wall apposition between the Enterprise and Enterprise 2 stents for treatment of cerebral aneurysms.

BACKGROUND: A closed-cell stent called Enterprise has been used for stent-assisted coil embolization of cerebral aneurysms. The Enterprise stent tends to cause kinks and vessel wall malposition in curved vessels and may cause thromboembolic complications. We evaluated vessel wall apposition of a new closed-cell stent, Enterprise 2, compared with a previous Enterprise stent, using curved vascular silicone models. METHODS: The Enterprise or Enterprise 2 stent was deployed in curved vascular models with various radii of approximately 5 to 10 mm. Stent deployment was performed 25 times in each stent. A push-pull technique was used to minimize incomplete wall apposition. To evaluate conformity of stents, gaps between a stent and a vessel wall were measured. RESULTS: The gap ratio (gap / a wall diameter) was 15 % ± 17 % (mean ± standard deviation) and 41 % ± 15 % with the Enterprise 2 stent and the Enterprise stent, respectively. Taking gap ratios and radii of vessel curvature into consideration, the Enterprise 2 stent had significantly better wall apposition than the Enterprise stent (p = 0.005). In the same radius of vessel curvature, the Enterprise 2 stent had approximately half of the gap compared with the Enterprise stent. There were no significant differences in vessel straightening effects between the two stents. CONCLUSIONS: The Enterprise 2 stent has better wall apposition in curved vessels than the Enterprise stent. The gap between a vessel wall and the Enterprise 2 stent is approximately half that of the Enterprise stent. However, gaps and kinks are still present in curved vessels with a small radius. Caution should be taken for kinks and malposition in acutely curved vessels, such as the siphon of the internal carotid artery.

Relationship between Angiographic Results and Morphology in Sidewall Intracranial Aneurysms after Stent-Assisted Coil Embolization.

BACKGROUND: Stent-assisted coil embolization (SACE) is used to address wide-necked or complex aneurysms. However, as they may recanalize after SACE, predictors of recanalization are needed. We investigated the relationship between follow-up angiographic results and the morphology of sidewall (SW) aneurysms in patients treated by SACE. METHODS: Between September 2010 and September 2014, we performed 80 SACE procedures for SW intracranial aneurysms. Angiographic findings, obtained immediately after the procedure, 3-6 months thereafter, and when aneurysmal recanalization was suspected on MR angiogram scan, were recorded. Morphologically, the SW aneurysms were classified as "outside" (OS) and "partially inside" (PI) based on the curve of the axes of the proximal or distal parent artery with respect to the aneurysmal neck. Follow-up angiographic studies on OS- and PI SW aneurysms were compared. RESULTS: On the initial angiograms, we classified 42 aneurysms as OS and 38 as PI. Immediately after SACE, there was no significant difference in the angiographic findings on OS and PI aneurysms. However, on follow-up angiograms, there was a significant difference in the rate of spontaneous improvement (4 of 42 [OS] versus 21 of 38 [PI], P = .001). We performed additional coil embolization to treat 3 recanalized OS aneurysms. CONCLUSIONS: SW aneurysms classified morphologically as PI tended to occlude progressively even after incomplete occlusion by SACE. In contrast, aneurysms classified as OS must be observed carefully after SACE.

Endovascular Treatment of Ruptured Large or Wide-Neck Basilar Tip Aneurysms Associated with Moyamoya Disease Using the Stent-Assisted Coil Technique.

BACKGROUND: Endovascular coiling is preferred to surgical clipping for the treatment of basilar tip aneurysms (BTAs) associated with moyamoya disease (MMD). However, there are few reports addressing the safety of stent treatment of aneurysms located on unaffected arteries in MMD patients. We report our experiences of stent-assisted coil embolization for ruptured large or wide-neck BTAs associated with MMD. METHODS: A retrospective review was conducted of 5 patients with ruptured BTAs associated with MMD treated by stent-assisted coil from January 2010 to December 2013 in our hospital. All presented with subarachnoid hemorrhage, and the diagnosis was confirmed by digital subtraction angiography. The procedure-related complications, immediate angiographic results, and clinical and angiographic follow-ups were analyzed. RESULTS: Successful embolization was performed without procedure-related complications in all 5 patients, of whom 3 were treated by single stent-assisted coiling, and the others were treated by Y-configured stent technique. Immediate angiographic results showed complete occlusion in 2 patients, neck residual in 1, and partial occlusion in 2. Postoperative angiographic follow-ups were obtained in all 5 cases at a mean time of 17.6 ± 9.3 months (range, 6-28 months). Follow-up angiographic examinations demonstrated total occlusion without in-stent restenosis in all cases, and all the patients reported good outcomes (modified Rankin Scale score, 0-2). CONCLUSIONS: Endovascular embolization using stent-assisted coiling proved to be a safe and efficient treatment for ruptured large or wide-neck BTAs associated with MMD; however, the long-term safety still remains to be confirmed.

The Safety and Efficacy of Triple Antiplatelet Therapy after Intracranial Stent-Assisted Coil Embolization.

BACKGROUND: Stent-assisted coil embolization is effective for intracranial aneurysms, especially for wide-necked aneurysms; however, the optimal antiplatelet regimens for postoperative ischemic events have not yet been established. We aimed at determining the efficacy and safety of a triple antiplatelet therapy regimen after intracranial stent-assisted coil embolization. METHODS: We retrospectively evaluated patients who underwent stent-assisted coil embolization for unruptured intracranial aneurysms or during the chronic phase of a ruptured intracranial aneurysm (≥ 4 weeks after subarachnoid hemorrhage onset). We recorded the incidence of ischemic and bleeding events 140 days postoperatively. RESULTS: We assessed 79 cases in patients who received either dual (n = 51) or triple (n = 28) antiplatelet therapy. The duration of triple antiplatelet therapy was 49 ± 29 days. Seven patients in the dual group experienced postoperative ischemic events. Compared to the dual group, the triple group had a similar incidence of postoperative bleeding events but a significantly lower incidence of postoperative ischemic events (P < .05). CONCLUSIONS: Triple antiplatelet therapy had a significantly lower incidence of postoperative ischemic events and a similar incidence of postoperative bleeding events 140 days postoperatively.

Bilateral Cavernous Carotid Aneurysms: The Growth Potential of a Contralateral Aneurysm after Therapeutic Unilateral Internal Carotid Artery Occlusion.

BACKGROUND: Although the introduction of flow-diverter stents has been recognized as a major revolution in the treatment of cavernous carotid aneurysms (CCAs), therapeutic internal carotid artery occlusion (TICAO) remains a reliable procedure for alleviating symptoms caused by CCAs. However, TICAO has the potential risk of the enlargement of coexisting aneurysms that are frequently detected in CCA patients. The purpose of this study is to assess the occurrence of the enlargement of aneurysms coexisting with CCAs after TICAO. METHODS: We reviewed medical charts of CCA patients who were managed using unilateral TICAO. Coexisting aneurysms were identified using angiograms obtained before TICAO, and imaging data in long follow-up periods were retrospectively examined to determine the extent of the enlargement after TICAO. RESULTS: Of 12 patients with CCAs, 10 had 12 coexisting aneurysms; 5 of the coexisting aneurysms (41.7%) showed enlargement during a mean follow-up period of 8.1 years, and all enlarged aneurysms were smaller of the bilateral CCAs; the larger CCA had been managed by TICAO. Five of 6 (83.3%) patients with bilateral CCAs showed enlargement of the contralateral aneurysm after TICAO. Two contralateral CCAs showed marked enlargement after TICAO and were subsequently treated with stent-assisted coil embolization. CONCLUSIONS: Contralateral, smaller aneurysms frequently enlarge after unilateral TICAO in patients with bilateral CCAs. The findings emphasize the importance of long-term observation after TICAO and appropriate interventions against enlarging contralateral aneurysms.

Growing dissecting aneurysm of basilar trunk treated with stent-assisted coiling.

Growing basilar dissecting aneurysm is a scarce but increasingly recognized entity, accounting for a significant risk of death and disability. Controversy exists regarding the optimal management. A 61-year-old man presented with dysarthria and left hemiparesis attributable to a basilar trunk dissecting aneurysm. Antiplatelet therapy was instituted, and the patient's clinical condition markedly improved. However, he developed severe headache, dysarthria, and left hemiparesis 35 days later. Angiography revealed significant enlargement of the aneurysm, and stent-assisted coiling was then uneventfully performed. The patient remained clinically stable with only mild left-sided hemiparesis at the 2-year clinical follow-up.

Onset Time of Ischemic Events and Antiplatelet Therapy after Intracranial Stent-assisted Coil Embolization.

BACKGROUND: Stent-assisted coil embolization is effective for intracranial aneurysms, especially wide-necked aneurysms; however, the optimal antiplatelet regimens for ischemic events that develop after coil embolization have not yet been established. We aimed to determine the onset time of such postoperative ischemic events and the relationship between these events and antiplatelet therapy. METHODS: We performed coil embolization using a vascular reconstruction stent for 43 cases of intracranial aneurysms and evaluated the incidence of postoperative ischemic events in these cases. RESULTS: Nine patients showed postoperative ischemic events during the follow-up period (13 ± 7 months). Two patients developed cerebral infarction within 24 hours. Five patients developed transient ischemic attack within 40 days while they were receiving dual antiplatelet therapy. In addition, 1 patient showed cerebral infarction 143 days postoperatively during single antiplatelet therapy, and a case of transient visual disturbance was reported 191 days postoperatively (49 days after antiplatelet therapy had been discontinued). We increased the number of antiplatelet agents in 4 of these patients. The other 5 patients were under strict observation with dual antiplatelet therapy. All these patients were shifted to single antiplatelet therapy 3-13 months postoperatively. No recurrence of ischemic events was noted. CONCLUSIONS: Postoperative ischemic events are most likely to occur within 40 days postoperatively. For patients with postoperative ischemic events, additional ischemic events can be prevented by increasing the number of antiplatelet agents; subsequently, they can be shifted to single antiplatelet therapy after the risk of recurrence has decreased.

A Case of a Perianeurysmal Cyst Following Stent-Assisted Coil Embolization of an Unruptured Vertebral Artery Aneurysm.

Objective: To report the rare case of a patient with a perianeurysmal cyst following stent-assisted coil embolization of an unruptured vertebral artery aneurysm. Case Presentation: 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. Conclusion: Aneurysms embedded in the brain parenchyma should be carefully followed up, recognizing the risk of perianeurysmal cyst formation after coil embolization.

Duration of dual-antiplatelet therapy after stent-assisted coil for unruptured intracranial aneurysm: A nationwide cohort study.

BACKGROUND: 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. AIM: To assess the time-dependent effect of DAPT on the risk of ischemic and hemorrhagic complications after SAC. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

The white-collar sign after Neuroform Atlas stent-assisted coil embolization of unruptured intracranial aneurysms.

PURPOSE: 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.

Considerations and Literature Review for Treating Subarachnoid Hemorrhage due to Blood Blister-Like Aneurysms.

Objective: 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. Methods: 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. Results: 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). Conclusion: 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.

Classification and hemodynamic characteristics of delayed intracerebral hemorrhage following stent-assisted coil embolism in unruptured intracranial aneurysms.

Background and objective: 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. Methods: 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. Results: 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. Conclusion: 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.

Factors predicting recanalization following stent-assisted coil embolization of unruptured intracranial aneurysms with long-term follow-up.

Objective: 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. Methods: 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. Results: 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. Conclusion: The maximum aneurysm size and parent artery curvature are risk factors associated with recanalization in stent-assisted coil embolization.

Balloon-Assisted Stent Visualization: A Simple Technique for Precise Measurement of Previously Placed Stent Diameter.

Stent-assisted coil embolization is effective for treating intracranial aneurysms, improving outcomes and reducing recurrence rates. However, accurately measuring the diameter of a previously placed stent during imaging can be challenging due to coil artifacts. This poses difficulties in determining the coil packing and size of additional stents needed during retreatment. In a reported case, the use of a balloon enabled precise assessment of stent deployment. A 50-year-old male with a history of basilar artery-left superior cerebellar artery aneurysm underwent coil embolization, direct clipping, and stent-assisted coil embolization (SAC) over a span of 14 years. However, the aneurysm showed reenlargement over time. To address the recurrence, a balloon was used to assess the previously placed Neuroform Atlas stent. Additional coils were inserted outside the stent, and a Low-profile Visualized Intraluminal Support Blue stent was added. Postoperatively, there were no new neurological issues, and a follow-up magnetic resonance imaging showed no ischemic lesions . Balloon-assisted stent visualization (BASV) may be a useful method in the retreatment of SAC. It has the potential to provide valuable information for treatment planning.