Risk Factors for the Recurrence of Distal Anterior Cerebral Artery Aneurysms After Endovascular Treatment.

OBJECTIVE: We aimed to investigate risk factors for the recurrence of distal anterior cerebral artery (DACA) aneurysms after endovascular treatment (EVT). METHODS: The clinical and radiologic outcomes of DACA aneurysms treated with endovascular methods at a single tertiary hospital from September 2008 to December 2021 were retrospectively reviewed. We measured the angle between 2 distal branches of DACA aneurysms and categorized the angle as follows: 1) wide-angle (≥180°), and 2) narrow-angle type configuration (<180°). Univariate and multivariate analyses were performed to demonstrate the relationships between characteristics of DACA aneurysm and recurrence risk. RESULTS: In total, 132 DACA aneurysms were treated in our institution. Among these, 47 DACA aneurysms after EVT were included in this study. Forty patients underwent coil embolization without stent, 7 for stent-assisted coil embolization. At the last follow-up (mean 30.2 ± 24.2 months), overall recurrence rate was 23.4% (n = 11). Recurrence rate of the wide-angle type (9 of 23, 39.1%) was significantly greater than narrow-angle type (2 of 24, 8.3%) (P = 0.041; odds ratio 8.174, 95% confidence interval 1.094-61.066). Irregular shape of the DACA aneurysm also showed significantly greater recurrence rate (P = 0.011; odds ratio 10.663, 95% confidence interval 1.701-66.838) after endovascular treatment. CONCLUSIONS: The wide-angle between 2 distal branches of DACA aneurysm and irregular shape might be independent risk factors for the recurrence after endovascular treatment for DACA aneurysms.

Transvenous embolization along with intraprocedural image fusion technique for complex intracranial dural arteriovenous fistula.

PURPOSE: This study aimed to investigate the efficacy and safety of an intraprocedural image fusion technique using flat-panel detector computed tomography-based rotational angiography (FDCT-RA) and image fusion (IF) for the transvenous approach in treating intracranial dural arteriovenous fistulas (dAVFs). METHODS: A retrospective review was conducted on patients who underwent transvenous embolization for dural AVFs. The patients were classified into two groups according to the treatment technique used: the FDCT-RA and IF technique group and the conventional technique group. The primary outcomes assessed were the angiographic and clinical outcomes, complications, fluoroscopy time, and radiation exposure. Univariate analyses were performed to compare the two treatment modalities. RESULTS: Eighty-six patients with intracranial dAVFs were treated with transvenous embolization (TVE), of which 37 patients underwent transvenous approach with flat-panel detector computed tomography-based rotational angiography (FDCT-RA) and image fusion (IF) technique used. The FDCT-RA and IF group showed difference in the location of dAVFs, occlusion state of the sinus, and access routes in comparison to the conventional treatment group. The FDCT-RA and IF technique was predominantly used for dAVFs involving the anterior condylar confluence and cavernous sinus with ipsilateral inferior petrosal sinus (IPS) occlusion. Patients treated with this technique demonstrated a higher rate of complete occlusion (91.9%, n = 34) compared to those treated with the conventional technique (79.6%, n = 39), but this difference was not statistically significant (p = 0.136). Although the implementation of this technique during the treatment procedure showed a tendency to decrease both fluoroscopy duration and radiation dose, the observed results did not reach statistical significance (p = 0.315, p = 0.130). CONCLUSION: The intraprocedural image fusion technique using FDCT-RA for transvenous treatment of intracranial dAVFs could provide help in treatment of dAVFs of certain locations or access routes. It might provide aid in microcatheter navigation, without increasing the radiation exposure and fluoroscopy time.

Image fusion technique using flat panel detector rotational angiography for transvenous embolization of intracranial dural arteriovenous fistula.

Precise evaluation of the feeders, fistulous points, and draining veins plays a key role for successful embolization of intracranial dural arteriovenous fistulas (DAVF). Digital subtraction angiography (DSA) is a gold standard diagnostic tool to assess the exact angioarchitecture of DAVFs. With the advent of new image postprocessing techniques, we lately have been able to apply image fusion techniques with two different image sets obtained with flat panel detector rotational angiography. This new technique can provide additional and better pretherapeutic information of DAVFs over the conventional 2D and 3D angiographies. In addition, it can be used during the endovascular treatment to help the accurate and precise navigation of the microcatheter and microguidwire inside the vessels and identify the proper location of microcatheter in the targeted shunting pouch. In this study, we briefly review the process of an image fusion technique and introduce our clinical application for treating DAVFs, especially focused on the transvenous embolization.

Clinical and Radiological Outcomes of Vertebral Artery Dissecting Aneurysms Treated with Endovascular Treatments: A 12-year Single-Center Experience.

OBJECTIVE: We aimed to compare the clinical and radiological outcomes of vertebral artery dissecting aneurysms (VADAs) stratified using different endovascular treatment methods. METHODS: We retrospectively reviewed 116 patients with VADAs treated at a single tertiary institute between September 2008 and December 2020. We analyzed and compared the clinical and radiological parameters according to different treatment methods. RESULTS: In total, 127 endovascular procedures were performed in 116 patients. We initially treated 46 patients with parent artery occlusion, 9 with coil embolization without stent, 43 with single stent with or without coil, 16 with multiple stents with or without coils, and 13 with flow-diverting stent. At the last follow-up (mean 37.8 ± 30.9 months), the complete occlusion rate (85.7%) was higher in the multiple-stent group than in the groups that received other reconstructive treatment methods. Moreover, the recurrence (0%) and retreatment (0%) rates were significantly lower in the multiple stent group (P < 0.001). The coil embolization-only group showed the highest recurrence (n = 5, 62.5%) and incomplete occlusion (n = 1, 12.5%) rates. The single-stent group showed higher recurrence (n = 9, 22.5%) and retreatment (n = 3, 7%) rates. Multivariate logistic regression analyses showed that coil embolization without stent placement (odds ratio = 172.76, 95% confidence interval = 6.83-4366.85; P = 0.002) was significantly associated with recurrence. At the last follow-up (mean, 42.1 ± 37.7 months), we achieved favorable clinical outcomes (modified Rankin Scale ≤2) in 106 of 127 patients. CONCLUSION: When treating VADAs, multiple stent placements may play a key role in achieving favorable long-term radiological outcomes.

Comparison of Parent Artery Occlusion and Stent-Assisted Treatments in Ruptured Vertebral Artery Dissecting Aneurysms.

OBJECTIVE: To assess clinical outcomes of ruptured vertebral artery dissecting aneurysms, focusing on comparing parent artery occlusion (PAO) with stent-assisted treatments, and to identify risk factors for unfavorable outcomes and postprocedural complications. METHODS: This retrospective review included 36 ruptured vertebral artery dissecting aneurysms treated between February 2009 and April 2020. Treatment modalities included PAO without stent and stent-assisted treatments. Stent-assisted treatments included PAO with posterior inferior cerebellar artery (PICA) stenting and stent-assisted coiling. Univariate and multivariate analyses were conducted to evaluate risk factors for unfavorable outcomes and postprocedural complications. RESULTS: Patients were treated with PAO only (24, 66.7%), PAO with PICA stenting (4, 11.1%), and PAO with stent-assisted coiling (8, 22.2%). There were only fusiform aneurysms with PICA involvement in the PAO with PICA stenting group. In the stent-assisted coiling group, 4 aneurysms incorporated PICA, and 4 aneurysms involved dominant vertebral artery. Old age (odds ratio [OR] = 1.25, 95% confidence interval [CI] = 1.01-1.56, P = 0.044) and poor Hunt-Hess grade (OR = 537.99, 95% CI = 6.73-42994.1, P = 0.005) were significantly associated with unfavorable clinical outcomes after a mean follow-up of 37.5 ± 32.8 months. Fusiform dilatation shape (OR = 15.97, 95% CI = 1.52-167.38, P = 0.021) and PICA involvement (OR = 13.71, 95% CI = 1.29-145.89, P = 0.030) were independent risk factors for ischemic complications. CONCLUSIONS: Unfavorable clinical outcomes were significantly related to old age and poor Hunt-Hess grade. There were no significant differences between treatment groups in clinical outcomes or ischemic complications. Stent-assisted treatments might be effective and safe methods for ruptured vertebral artery dissecting aneurysms.

Acute Ischemic Stroke Caused by Internal Carotid Artery Occlusion: Impact of Occlusion Type on the Prognosis.

BACKGROUND: We aimed to compare clinical outcomes of acute ischemic stroke (AIS) due to internal carotid artery (ICA) occlusion following mechanical thrombectomy (MT), focusing on occlusion types. METHODS: We retrospectively reviewed 67 AIS patients who had an ICA occlusion on computed tomography angiography and underwent MT in a single tertiary center. ICA occlusion types were categorized as (1) true cervical ICA (cICA) occlusion (true occlusion), (2) pseudo-occlusion of the cICA (pseudo-occlusion), and (3) distal ICA (dICA) occlusion. We compared the clinical characteristics and their outcomes according to the ICA occlusion type. RESULTS: Fourteen patients were diagnosed with true occlusion, 32 with pseudo-occlusion, and 21 with dICA occlusion. The main etiologies were atherothrombotic in true occlusion (64.3%) and cardioembolic in pseudo-occlusion (81.3%) and dICA occlusion (71.4%) (P < 0.001). Pseudo-occlusion showed lower rates of successful reperfusion (37.5%, P = 0.009, 78.6% in true occlusion and 71.4% in dICA occlusion) and poor functional outcome at 3 months (18.8%, P = 0.037, 50% in true occlusion and 47.6% in dICA occlusion) with statistical significance. The infarction volume (169.4 ± 154.4 mL, P = 0.004, 29.2 ± 52.7 mL in true occlusion and 105.8 ± 13.4 mL in dICA occlusion) was significantly higher in pseudo-occlusion. On multivariate logistic analysis, pseudo-occlusion (odds ratio [OR]: 4.84, 95% confidence interval [CI] 1.02-22.87, P = 0.023) was an independent risk factor for poor reperfusion, which was significantly associated with a poor functional prognosis (OR: 22.04, 95% CI 1.99-243.83, P = 0.012). CONCLUSIONS: Patients with pseudo-occlusion showed poorer clinical outcomes compared with other ICA occlusion types, possibly due to a poor reperfusion rate after MT.

Symptomatic ischemic complications following endovascular treatment of vertebral artery dissecting aneurysms.

PURPOSE: The aim of this study is to investigate the clinical and radiological features related to the symptomatic ischemic complications of vertebral artery dissecting aneurysm (VADA) following endovascular treatment (EVT). METHODS: The clinical and radiological features of 127 VADAs, which were treated in a single tertiary institute between September 2008 and December 2020, were retrospectively reviewed. We defined a thrombosed aneurysm as being one which the thrombus was in the aneurysm in magnetic resonance imaging (MRI). Symptomatic ischemic complication was defined as a case in which acute infarction was confirmed on diffusion weighted image after EVT with associated clinical symptoms. Univariate and multivariate analyses were executed to demonstrate the associations between symptomatic ischemic complication and characteristics of VADA. RESULTS: The rate of symptomatic ischemic complication was 13.4% (17 of 127). The thrombosed aneurysms were observed in 24.4% (31 of 127) and posterior inferior cerebellar artery (PICA) involvement was shown in 38.6% (49 of 127). Multivariate logistic regression analysis demonstrated that thrombosed aneurysms (odds ratio [OR] = 8.54, 95% confidence interval [CI] 1.98-36.87, p = 0.004) and PICA involvement (OR = 4.26, 95% CI 1.03-17.68, p = 0.046) were significantly associated with symptomatic ischemic complications following EVT. CONCLUSION: This study showed that the VADAs with intra-aneurysmal thrombose and PICA involvement may be independent risk factors for symptomatic ischemic complications following EVT. Therefore, when the thrombosed VADAs with PICA involvement are observed, practitioners may consider close postoperative monitoring for early detection of ischemic complications.

A Single Flow Re-direction Endoluminal Device for the Treatment of Large and Giant Anterior Circulation Intracranial Aneurysms.

PURPOSE: The purpose of this study was to report the author's experiences in treating large (10-25 mm) and giant (>25 mm) intracranial aneurysms (IAs) using a single Flow Re-direction Endoluminal Device (FRED) without assistant coiling, with a focus on procedure-related complications. MATERIALS AND METHODS: A total of 33 patients who were treated with FRED between January 2018 and July 2020 were retrospectively reviewed. The timing of procedure-related complications was chronologically categorized as acute (within 7 days), subacute (8 to 21 days), and delayed (after 21 days) periods. Follow-up angiography was performed at 2 to 27 months (mean 9.7 months), and clinical follow-up was performed at 1 to 31 months (mean 14.1 months) in all patients. RESULTS: Six (18.2%) patients experienced procedure-related complications, including 2 (6.1%) in acute period, 1 (3.0%) in subacute period, and 3 (9.1%) in delayed period. Thromboembolic complications occurred in 5 (15.2%) patients and hemorrhagic complications in 1 (3.0%). Permanent morbidity and mortality rates were 3.0% each. Non-internal carotid artery (ICA) location of IAs (odds ratio 6.532; 95% confidence interval, 1.335-17.816; p=0.034) was the only independent risk factor for procedure-related complications on multivariate logistic regression analysis. CONCLUSION: The procedure-related complication rate was 18.2% in this study. Procedure-related complications might increase when treating large and giant IAs located on a non-ICA, especially on the middle cerebral artery. Therefore, it may be suggested that neurointerventionists and endovascular neurosurgeons should pay attention to the location of IAs when treating large and giant IAs with a single FRED.

Low-Dose Three-Dimensional Rotational Angiography for Evaluating Intracranial Aneurysms: Analysis of Image Quality and Radiation Dose.

OBJECTIVE: This study aimed to evaluate the image quality and dose reduction of low-dose three-dimensional (3D) rotational angiography (RA) for evaluating intracranial aneurysms. MATERIALS AND METHODS: We retrospectively evaluated the clinical data and 3D RA datasets obtained from 146 prospectively registered patients (male:female, 46:100; median age, 58 years; range, 19-81 years). The subjective image quality of 79 examinations obtained from a conventional method and 67 examinations obtained from a low-dose (5-seconds and 0.10-µGy/frame) method was assessed by two neurointerventionists using a 3-point scale for four evaluation criteria. The total image quality score was then obtained as the average of the four scores. The image quality scores were compared between the two methods using a noninferiority statistical testing, with a margin of -0.2 (i.e., score of low-dose group - score of conventional group). For the evaluation of dose reduction, dose-area product (DAP) and air kerma (AK) were analyzed and compared between the two groups. RESULTS: The mean total image quality score ± standard deviation of the 3D RA was 2.97 ± 0.17 by reader 1 and 2.95 ± 0.20 by reader 2 for conventional group and 2.92 ± 0.30 and 2.95 ± 0.22, respectively, for low-dose group. The image quality of the 3D RA in the low-dose group was not inferior to that of the conventional group according to the total image quality score as well as individual scores for the four criteria in both readers. The mean DAP and AK per rotation were 5.87 Gy-cm² and 0.56 Gy, respectively, in the conventional group, and 1.32 Gy-cm² (p < 0.001) and 0.17 Gy (p < 0.001), respectively, in the low-dose group. CONCLUSION: Low-dose 3D RA was not inferior in image quality and reduced the radiation dose by 70%-77% compared to the conventional 3D RA in evaluating intracranial aneurysms.

Long-term clinical and angiographic outcome from angioplasty and stenting for intracranial stenosis.

BACKGROUND: Severe intracranial atherosclerotic stenosis (ICAS) is a major cause of stroke. Although percutaneous transluminal angioplasty and stenting (PTAS) treatment methods have increased over the last decade as alternative therapies, there is debate regarding the best method of treatment, with medical and surgical therapies often suggested. METHODS: We analyzed the long-term follow-up results from 5 years of intracranial stenting for intracranial stenosis from three stroke centers. The primary endpoints were early stroke complications or death within 30 days after stent insertion, and the secondary endpoint was a recurrent stroke between 30 days and 60 months. Correlating factors and Kaplan-Meier survival curves for recurrent stroke and in-stent restenosis (ISR) were also obtained. RESULTS: Seventy-three PTAS in 71 patients were examined in this study. The primary and secondary endpoints were all 8.2% (n = 6), and restenosis was 13.7% (n = 10) during the 5-year follow-up. The primary endpoints were significantly frequent in the high National Institutes of Health Stroke Scale (NIHSS) and early stent (≤ 7 days after dual antiplatelet medication) groups. Secondary endpoint and ISR were identically frequent in the younger age group and in the presence of tandem stenosis in other major intracranial arteries. The cumulative probability of recurrent stroke and ISR at 60 months was 16.4% and 14.1%, respectively. CONCLUSIONS: This study shows that PTAS is safe and effective for major ICAS. Reducing the early complication rate is still an important factor, despite the fact that long-term stroke recurrence was low.

Basilar artery trunk aneurysm: clinical and angiographic outcomes of endovascular treatment.

BACKGROUND: Basilar artery (BA) trunk aneurysms are rare, and the clinical characteristics and outcomes of endovascular treatment (EVT) remain unclear. The purpose of this study was to report clinical and angiographic outcomes of BA trunk aneurysm treated with EVT and to analyze risk factors for unfavorable outcomes. METHODS: From October 2004 to December 2020, a total of 40 patients with BA trunk aneurysms underwent EVT. Clinical characteristics and outcomes were evaluated retrospectively from a prospectively collected database. Of the 40 enrolled patients, nine were treated by coiling without stents, 17 were treated by stent-assisted coiling, six by stent only, five by flow diverters, and three by vertebral artery occlusion. RESULTS: In total, 27 (67.5%) patients had subarachnoid hemorrhage as an initial presentation, and 20 (50.0%) had large/giant aneurysms. Procedure-related complications occurred in five patients (12.5%); favorable clinical outcome was achieved in 27 patients (67.5%); and six patients (15.0%) died. Favorable angiographic outcome was achieved in 26 (83.9%) of 31 patients who underwent follow-up angiography. Poor initial Hunt-and-Hess grade (OR 7.67, 95% CI 1.55 to 37.80; p=0.018) was the only independent risk factor for unfavorable clinical outcome. Large/giant aneurysm (OR 8.14, 95% CI 1.88 to 27.46; p=0.047) and long lesion (OR 14.25, 95% CI 1.48 to 69.80; p=0.013) were independent risk factors for unfavorable angiographic outcomes during follow-up. CONCLUSIONS: EVT might be a feasible option for this rare disease entity. Unfavorable angiographic outcome might be expected in a large/giant aneurysm or a long lesion. It can be difficult to treat BA trunk aneurysms by EVT, needing multiple procedures or various techniques due to diverse clinical and angiographic features.

Clinical and radiological risk factors for rupture of vertebral artery dissecting aneurysm: significance of the stagnation sign.

OBJECTIVE: The aim of this study was to investigate the clinical and radiological factors associated with the rupture of a vertebral artery dissecting aneurysm (VADA) and to evaluate whether the stagnation sign is a significant risk factor for rupture of VADA. METHODS: Clinical and radiological variables of 117 VADAs treated in a tertiary hospital from September 2008 to December 2020 were retrospectively reviewed. The stagnation sign is defined as the finding of contrast agent remaining in the lesion until the venous phase of angiography. Univariate and multivariate analyses were executed to reveal the associations between rupture status and VADA characteristics. RESULTS: The rate of ruptured VADAs was 29.1% (34 of 117) and the stagnation sign was observed in 39.3% (46 of 117). Fusiform shape (OR 5.105, 95% CI 1.591-16.383, p = 0.006), irregular surface (OR 4.200, 95% CI 1.412-12.495, p = 0.010), posterior inferior cerebellar artery (PICA) involvement (OR 3.788, 95% CI 1.288-11.136, p = 0.016), and the stagnation sign (OR = 3.317, 95% CI 1.131-9.732, p = 0.029) were significantly related to rupture of VADA in multivariate logistic regression analysis. CONCLUSIONS: This study showed that fusiform shape, irregular surface, PICA involvement, and the stagnation sign may be independent risk factors for the rupture of VADA. Therefore, when the potential risk factors are observed in unruptured VADA, more aggressive treatment rather than follow-up or medical therapy may be considered.

Multiple anterior choroidal arteries and perioperative ischemic complications in unruptured anterior choroidal artery aneurysms treated with microsurgical clipping.

BACKGROUND: This study aimed to identify the association between the number of anterior choroidal arteries (AchoAs) and procedure-related ischemic complications in microsurgical clipping of unruptured AchoA aneurysms. METHODS: We retrospectively reviewed the clinical, radiological, and intraoperative findings of 153 patients with unruptured AchoA aneurysms treated with microsurgical clipping between January 2012 and November 2020 in a single tertiary institution. Intraoperative video clips were reviewed, and the AchoA type was categorized into two according to the number of AchoAs: (1) single-type group with single origin and single branch and (2) multiple-type group with duplicated origin or divided multiple branches. Uni- and multivariate analyses were performed to assess the relationship between clinical and radiological factors and perioperative ischemic complications. RESULTS: Of the 153 patients, 52 (34%) were categorized as multiple-type group. The frequency of perioperative ischemic complications, including decreased intraoperative motor evoked potential (MEP), silent infarction, and postoperative ischemic symptoms, was significantly higher in the multiple-type group than in the single-type group (13 [25%] vs 6 [5.9%], p = 0.001). Multivariate logistic regression analysis showed that multiple-type group (odds ratio [OR], 3.725; 95% confidence interval [CI], 1.171-11.845, p = 0.026) and multilobulated shape (OR, 9.512; 95% CI, 2.093-43.224; p = 0.004) were significantly associated with perioperative ischemic complications. Among 9 patients with decreased MEP, postoperative ischemic symptoms developed in 2 patients after clip adjustment. CONCLUSIONS: Multiple-type AchoA aneurysms and multilobulated shape are significantly correlated with perioperative ischemic complications. Postoperative ischemic complications can be minimized by recognizing these variations and using multimodal approach with MEP monitoring.

Risk Factors for the Recurrence of Posterior Communicating Artery Aneurysm: The Significance of Fetal-Type Posterior Cerebral artery.

OBJECTIVES: The purpose of this study was to investigate the risk factors associated with recurrence of posterior communicating artery aneurysms after treatment and to evaluate the significance of fetal-type posterior cerebral artery as an independent risk factor for recurrence of posterior communicating artery aneurysms. MATERIALS AND METHODS: The clinical and radiological findings of 220 posterior communicating artery aneurysms treated between January 2009 and December 2016 in a single tertiary institute were retrospectively reviewed. Univariate and multivariate analyses were performed to evaluate the association between clinical and radiological variables and recurrence. RESULTS: Of 220 posterior communicating artery aneurysms, 148 aneurysms were unruptured and 82 aneurysms were treated with surgery. Forty-six out of 220 aneurysms (20.9%) were associated with fetal-type posterior cerebral artery. Overall recurrence rate was 19% (42 out of 220 aneurysms) during mean 54.6 ± 29.8 months follow-up. Multivariate logistic regression analysis showed that size (OR=1.238; 95% CI, 1.087-1.409, p = 0.001), ruptured status (OR=2.699; 95% CI, 1.179-6.117, p = 0.019), endovascular treatment (OR=3.803; 95% CI, 1.330-10.875, p = 0.013), incomplete occlusion (OR=4.699; 95% CI, 1.999-11.048, p = <0.001) and fetal-type posterior cerebral artery (OR=3.533; 95% CI, 1.373-9.089, p = 0.009) were significantly associated with recurrence after treatment. CONCLUSIONS: The results demonstrated that fetal-type posterior cerebral artery may be an independent risk factor for the recurrence of posterior communicating artery aneurysms. Therefore, fetal-type posterior cerebral artery can be considered as an important risk factor for the recurrence of posterior communicating artery aneurysms, along with other known risk factors such as size, ruptured status, endovascular treatment, and incomplete occlusion.

Low-Dose 3D Rotational Angiography in Measuring the Size of Intracranial Aneurysm: In Vitro Feasibility Study Using Aneurysm Phantom.

PURPOSE: Three-dimensional (3D) measurement of intracranial aneurysms is important in planning endovascular treatment, and 3D rotational angiography (RA) is effective in accurate measurement. The purpose of this study was to evaluate the feasibility of low dose 3D RA (5 seconds 0.10 µGy/frame) in measuring an intracranial aneurysm using an in vitro phantom. MATERIALS AND METHODS: We investigated an in vitro 3D phantom of an intracranial aneurysm with 10 acquisitions of 3D RA with a conventional dose (5 seconds 0.36 µGy/frame) and 10 acquisitions with a low-dose (5 seconds 0.10 µGy/frame). 3D size and neck diameters of the aneurysm were measured and compared between the 2 groups (conventional and low-dose) using noninferiority statistics. RESULTS: The aneurysm measurements were well-correlated between the 2 readers, and noninferiority in the measurement of aneurysmal size of low-dose 3D RA was demonstrated, as the upper margin of the 1-sided 97.5% confidence interval did not cross the pre-defined noninferiority margin of 0.2 mm by the 2 readers. CONCLUSION: Low-dose (5 seconds 0.10 µGy/frame) cerebral 3D RA is technically feasible and not inferior in in vitro 3D measurement of an intracranial aneurysm. Thus, low-dose 3D RA is promising and needs further evaluation for its clinical utility in the planning of endovascular treatment of an intracranial aneurysm.

Association of Anterior Cerebral Artery Variants and Cerebral Infarction in Patients with Balloon-Assisted Coil Embolization for Unruptured Internal Carotid Artery Aneurysms.

BACKGROUND: Balloon-assisted coiling (BAC) is an endovascular treatment that may be associated with increased complications and thromboembolic events compared with other coiling techniques. We compared clinical outcomes of endovascular treatment (simple coiling, stent-assisted coiling, and BAC) in patients with unruptured intracranial aneurysms at the internal carotid artery and assessed risk factors that could cause cerebral infarction in patients who underwent BAC. METHODS: We retrospectively reviewed the records of 528 patients with 544 aneurysms who underwent endovascular treatment for unruptured intracranial aneurysms between January 2013 and November 2019. Demographic features, clinical information, balloon inflation time, fetal posterior cerebral artery, anterior cerebral artery (ACA) variants, and angiographic results were analyzed to determine risk factors for cerebral infarction. RESULTS: There were no significant differences among the 3 groups in terms of general characteristics. In the BAC group, 14 of 39 patients showed a significantly higher incidence of cerebral infarction on diffusion magnetic resonance imaging compared with the stent-assisted coiling (37/238) and simple coiling (21/267) groups (P < 0.001). There was no significant difference between the ACA variants (normal vs. hypoplasia or aplasia) and cerebral infarction in the simple coiling and stent-assisted coiling groups, but the proportion of aplasia or hypoplasia in the BAC group was significantly higher (P = 0.001). CONCLUSIONS: There is a significant association between anatomic ACA variants and cerebral infarction occurrence after BAC. Identifying the variant of the anatomic ACA using digital subtraction angiography would help to predict cerebral infarction after BAC.

Treatment outcomes of large and giant intracranial aneurysms according to various treatment modalities.

PURPOSE: This study aimed to compare the treatment outcomes of large (15-25 mm) and giant (> 25 mm) intracranial aneurysms (IAs), according to different treatment modalities. METHODS: In total, 112 patients with large and giant IAs treated with various treatment modalities between January 2009 and December 2018 were retrospectively reviewed. Clinical and radiological parameters were analyzed and correlated with the treatment modality. RESULTS: A total of 141 procedures were performed on 112 patients. We initially treated 47 cases with coil embolization, 39 with flow diverter (FD), 13 with direct clipping, and 13 with parent artery occlusion (PAO). Recurrence (46.8%) and retreatment (31.9%) rates were significantly higher in the coiling group (p < 0.001). Complete occlusion rate (36.3%) was significantly lower in the coiling group (p = 0.027). PAO could achieve a high complete occlusion rate (90.9%) with low complication rate (12.5%). The total complication rate was 17%. In the multivariate logistic regression analysis, FD (OR 3.406, p = 0.036) and direct clipping (OR 5.732, p = 0.017) showed a significantly higher complication rate than coiling. The overall mortality rate was 8% (8/139 procedures). At the last follow-up (mean 30.6 ± 26.4 months), 70 of 96 patients (72.9%) showed complete or near-complete occlusion. Good functional outcome (mRS ≤ 2) was observed in 90 of 112 (80.3%) patients at the last follow-up (mean 33.2 ± 30.5 months). CONCLUSIONS: Good clinical and radiologic outcomes with acceptable complication and mortality rates can be achieved by various treatment modalities. The selection of appropriate modality should be individualized based on the angiographic findings and clinical symptoms.

Treatment outcome after coiling or clipping for elderly patients with unruptured intracranial aneurysms.

OBJECTIVE: The purpose of this study was to analyze treatment outcomes according to treatment modality for elderly patients over 75 years with unruptured intracranial aneurysm. METHODS: Fifty-four elderly patients treated in a single tertiary institute between January 2010 and December 2018 were retrospectively reviewed. We compared clinical outcome, radiological results, and complications between the coiling and clipping groups. RESULTS: A total of 55 procedures were performed in 54 patients. Of 55 aneurysms, 44 were treated endovascularly and 11 were treated surgically. There was no significant difference in patient baseline characteristics including mean age, sex, and preexisting co-morbidity between the two groups. Even though there was no significant difference (p=0.373), procedure-related symptomatic complication occurred only in coiling group (3 out of 44 patients, 6.6%). Mortality rate was significantly higher in clipping group (1 out of 11 patients, 9.1%) than in coiling group (0%, p=0.044). Good clinical outcome (modified Rankin Scale 0-2) at 90 days was achieved in 43 cases treated with coiling (97.7%), and 10 cases with clipping (90.9%, p=0.154). CONCLUSIONS: Clipping is more invasive procedure and takes longer operation time, which might lead to unpredictable mortality in elderly patients. Coiling might have high procedure-related stroke rate due to tortuous vessels with atherosclerosis. Therefore, aggressive treatment of elderly patients should be carefully considered based on patient's medical condition and angiographic findings.

Clinical and morphological risk factors for the recurrence of anterior communicating artery aneurysms after clipping or coiling.

BACKGROUND: The aim of this study was to evaluate clinical and morphological factors associated with recurrence in anterior communicating artery (AcomA) aneurysms after clipping or coiling. METHODS: We retrospectively reviewed the clinical and radiologic features of consecutive 214 patients with AcomA aneurysms treated between January 2012 and December 2016 in a single tertiary institute. Univariate and multivariate analyses were performed to identify the relationship between clinical and morphological variables and recurrence. RESULTS: Of 214 patients, 166 were unruptured aneurysms and 109 were treated with coiling. Overall recurrence rate was 13% (28 out of 214 aneurysms) during mean 36.9 ± 18.4-month follow-up. Multivariate logistic regression analysis showed that size greater than 10 mm (OR = 5.651; 95% CI, 1.317-24.242; p = 0.020), smoking (OR = 3.474; 95% CI, 1.342-8.996; p = 0.010), coiling (OR = 2.98; 95% CI, 1.005-8.832; p = 0.049), and anterior direction of aneurysm (OR = 3.77; 95% CI, 1.12-12.66; p = 0.032) were significantly associated with recurrence of AcomA aneurysms after treatment. CONCLUSIONS: The results of this study demonstrated that coiling, large aneurysm, anterior direction, and smoking history may be independent risk factors for the recurrence of AcomA aneurysms. Therefore, careful follow-up should be needed especially in large AcomA aneurysms with anterior direction after coiling.

Immediate Postoperative Angiographic Stagnation of Contrast Media and T2-Weighted Magnetic Resonance Imaging Features within Aneurysmal Sac Are Associated with Early Regression of Large or Giant Aneurysm After Flow Diversion Only.

BACKGROUND: We hypothesized that the immediate postoperative imaging features would be associated with early regression of flow-diverted aneurysms. We compared the imaging features from digital subtraction angiography and spin echo T2-weighted magnetic resonance imaging between those with early total regression and partial regression. METHODS: A total of 30 consecutive patients with large and giant aneurysms were treated with pipeline embolization devices and divided into 2 groups according to the follow-up angiographic findings at 3-6 months. Of the 30 patients, 20 had had total or near total regression and 10 had had partial regression of the aneurysmal sac. The baseline characteristics, percent area of stagnated iodine contrast agent on anteroposterior and lateral angiographic views just after installation of the pipeline device, and median, minimal, and 10-percentile signal intensity of the aneurysmal sac on T2-weighted spin echo images 1 day after the procedure were compared between the 2 groups. RESULTS: A comparison of the demographic data between the 2 groups showed no significant differences. The volume of the treated aneurysmal sac also did not differ significantly (2559.28 ± 3021.45 mm3 vs. 2551.76 ± 6550.58 mm3; P = 0.455). The total or near total regression group had a larger percent area of iodine stagnation on the lateral angiographic view compared with the partial regression group (52.26% vs. 23.35%; P = 0.002). The median, minimal, and 10-percentile signal intensity of the volume of interest were higher in the total or near total regression group than in the partial regression group (1.29 vs. 0.93 [P = 0.025]; 0.07 vs. 0.00 [P = 0.042]; 0.57 vs. 0.24 [P = 0.005]). CONCLUSIONS: The percent area of contrast media stagnation on lateral angiograms and the median, minimal, and 10th-percentile signal intensity of the volume of interest of treated aneurysmal sacs on T2-weighted images can be used to predict early regression of aneurysmal sacs.