14N NMR of magnetically oriented microcrystals.

14N NMR of magnetically oriented microcrystals is reported. With a home-built 1H-13C-14N probe capable of modulating the rotation of the sample around the axis normal to the magnetic field, magnetically oriented microcrystal suspension (MOMS) of l-alanine is made. 14N NMR spectra acquired with various timings during intermittent rotation lead to a rotation pattern of the MOMS similar to that of a single crystal. The effect of orientational distribution of the microcrystals to broadening of the resonance line is discussed.

Recurrence of an extracranial internal carotid artery aneurysm treated with STA-MCA bypass and trapping due to neovascularization from an ascending pharyngeal artery: illustrative case.

BACKGROUND: Extracranial internal carotid artery aneurysms (EICAs) are rare. Although a high mortality risk has been reported in nonoperated cases, the optimal treatment for EICAs remains unknown. OBSERVATIONS: A 79-year-old female presented with painless swelling in the right neck. Imaging revealed a giant EICA with a maximum diameter of 3.2 cm. Superficial temporal artery-middle cerebral artery bypass and internal carotid artery (ICA) trapping were performed. Because the distal aneurysm edge was at the C1 level, the distal portion of the aneurysm was occluded by endovascular coiling, and the proximal portion was surgically ligated. Blood flow into the aneurysm disappeared after the operation. Three years postsurgery, enlargement of the aneurysm with blood flow from the ascending pharyngeal artery (APA) was detected. The EICA was resected after coiling the APA and ligating both ends of the aneurysm. Pathologically, neovascularization within the aneurysm wall was observed. LESSONS: Even if blood flow into an EICA disappears after ICA trapping, the EICAs can enlarge due to neovascularization from the neighboring artery. From the outset, removal of the aneurysm should be considered as a radical treatment strategy for giant EICAs.

Fluid dynamic analysis in predicting the recanalization of intracranial aneurysms after coil embolization - A study of spatiotemporal characteristics.

Purpose: Hemodynamics play a key role in the management of cerebral aneurysm recanalization after coil embolization; however, the most reliable hemodynamic parameter remains unknown. Previous studies have explored the use of both spatiotemporally averaged and maximal definitions for hemodynamic parameters, based on computational fluid dynamics (CFD) analysis, to build predictive models for aneurysmal recanalization. In this study, we aimed to assess the influence of different spatiotemporal characteristics of hemodynamic parameters on predictive performance. Methods: Hemodynamics were simulated using CFD for 66 cerebral aneurysms from 65 patients. We evaluated 14 types of spatiotemporal definitions for two hemodynamic parameters in the pre-coiling model and five in virtual post-coiling model (VM) created by cutting the aneurysm from the pre-coiling model. A total of 91 spatiotemporal hemodynamic features were derived and utilized to develop univariate predictor (UP) and multivariate logistic regression (LR) models. The model's performance was assessed using two metrics: the area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC). Results: Different spatiotemporal hemodynamic features exhibited a wide range of AUROC values ranging from 0.224 to 0.747, with 22 feature pairs showing a significant difference in AUROC value (P-value <0.05), despite being derived from the same hemodynamic parameter. PDave,q1 was identified as the strongest UP with AUROC/AUPRC values of 0.747/0.385, yielding sensitivity and specificity value of 0.889 and 0.614 at the optimal cut-off value, respectively. The LR model further improved the prediction performance, having AUROC/AUPRC values of 0.890/0.903. At the optimal cut-off value, the LR model achieved a specificity of 0.877, sensitivity of 0.719, outperforming the UP model. Conclusion: Our research indicated that the characteristics of hemodynamic parameters in terms of space and time had a significant impact on the development of predictive model. Our findings suggest that LR model based on spatiotemporal hemodynamic features could be clinically useful in predicting recanalization after coil embolization in patients, without the need for invasive procedures.

Periprocedural antiplatelet medication assessed by VerifyNow for neuroendovascular treatment: Comparison of prasugrel with clopidogrel.

OBJECTIVE: The maintenance dose of prasugrel (PRAS) for neuroendovascular treatment requires much research. We report the antiplatelet effect of PRAS measured by VerifyNow P2Y12 reaction units (PRUs) in patients during the perioperative period of neuroendovascular treatment. METHODS: Between January 2017 and January 2023, 230 patients who underwent endovascular treatment for unruptured intracranial aneurysms or carotid artery stenosis at our institution were retrospectively identified. Patients received dual antiplatelet therapy with 100 mg aspirin (ASA) and 75 mg clopidogrel (CLP)/day (CLP group, n = 186) or 100 mg ASA and 3.75 mg PRAS/day (PRAS group, n = 44) 2 weeks before the procedures. The PRU value was compared between the CLP and PRAS groups. In the study, we defined 95≦PRU < 208 as the optimal range. Perioperative complications within seven days of surgery were also analyzed. RESULTS: The mean value of PRU was significantly low in the PRAS group (179.13 ± 66.03 in CLP vs. 154.75 ± 54.01 in PRAS, p = 0.024). The proportion of the patients who exhibited 95≦PRU < 208 was significantly higher in the PRAS group (55.4% vs. 72.7%, p = 0.036). Ischemic and hemorrhagic complication rates were not significantly different between the CLP and PRAS groups (7.6% vs. 0%, p = 0.076; 4.7% vs. 0%, p = 0.361). The ischemic complication rate was higher in patients with a PRU > 208 than in those with PRU < 208 (12.5% vs. 3.8%, p = 0.044). The hemorrhagic complication rate was not significantly different between the PRU < 95 and 95≦PRU groups (8.4% vs. 3.2%, p = 0.224). CONCLUSIONS: Maintenance dose PRAS further decreased the PRU value and reached the optimal range in more cases than CLP during the perioperative period of neuroendovascular treatment. Ischemic complications significantly increased in the 208 < PRU group.

Sympathetic Nervous Hyperactivity Impairs Microcirculation Leading to Early Brain Injury After Subarachnoid Hemorrhage.

BACKGROUND: Although early brain injury (EBI) is recognized as a critical step following subarachnoid hemorrhage (SAH), its pathophysiology and underlying mechanisms remain poorly understood. Herein, we investigated the role of cerebral circulation in the acute phase using patient data and a mouse SAH model and evaluated its regulation via the sympathetic nervous system. METHODS: The cerebral circulation time and neurological outcomes in the human body were retrospectively examined in 34 SAH cases with ruptured anterior circulation aneurysms and 85 cases with unruptured anterior circulation cerebral aneurysms at Kanazawa University Hospital from January 2016 to December 2021. In a mouse study, a SAH model was created via endovascular perforation, and India-ink angiography was performed over time. Additionally, bilateral superior cervical ganglionectomy was performed immediately before surgery, and neurological scores and brain water content were evaluated after SAH. RESULTS: Cerebral circulation time was prolonged in the acute phase of SAH compared with that in the unruptured cerebral aneurysm group, especially in those with electrocardiographic changes. Furthermore, it was more prolonged in the poor prognosis group (modified Rankin Scale scores 3-6) than in the good prognosis group (modified Rankin Scale scores 0-2) at discharge. In mice, cerebral perfusion was significantly reduced at 1 and 3 hours after SAH and recovered at 6 hours. superior cervical ganglionectomy improved cerebral perfusion without altering the diameter of the middle cerebral artery at 1 hour and improved neurological outcomes at 48 hours after SAH. Consistently, brain edema, quantified by brain water content, was improved by superior cervical ganglionectomy 24 hours after SAH. CONCLUSIONS: Sympathetic hyperactivity may play a critical role in the development of EBI by impairing cerebral microcirculation and edema in the acute phase following SAH.

[Monitoring during Cerebrovascular Surgery].

Intraoperative monitoring of cerebrovascular disease is performed in direct surgery and endovascular treatment to prevent complications due to blood flow disturbance. Typical surgeries in which monitoring is useful are revascularization surgeries, such as bypass, carotid endarterectomy, and aneurysm clipping surgery. Revascularization is performed to normalize intracranial and extracranial blood flow but requires interruption of blood flow to the brain, even for a short time. Changes in cerebral circulation and function when blood flow is blocked cannot be generalized because they are affected by collateral circulation and differ among cases. Monitoring is important to understand these changes during surgery. It is also used in revascularization procedures to check if the reestablished cerebral blood flow is adequate. Changes in monitoring waveforms can detect the emergence of neurological dysfunction, but in some cases, clipping surgery can end with missing waveforms, leading to dysfunction. Even in such cases, it can help identify which surgery caused the malfunction and improve the outcome of subsequent surgeries.

The first coil embolization ratio is the key factor for retreatment for unruptured cerebral aneurysms.

Background: In coil embolization, a high volume embolization ratio prevents recanalization that may require retreatment. However, patients with a high volume embolization ratio may also require retreatment. Patients with inadequate framing with the first coil may experience recanalization of the aneurysm. We analyzed the relationship between embolization ratio of the first coil and recanalization requiring retreatment. Methods: We reviewed data from 181 patients with unruptured cerebral aneurysms who underwent initial coil embolization between 2011 and 2021. We retrospectively analyzed the correlation between neck width, maximum aneurysm size, width, aneurysm volume, volume embolization ratio of the framing coil (first volume embolization ratio [1st VER]), and final volume embolization ratio (final VER) of cerebral aneurysms in patients and their retreatment. Results: Recanalization requiring retreatment was observed in 13 patients (7.2%). The factors related to recanalization were neck width, maximum aneurysm size, width, aneurysm volume, and 1st VER, but not the final VER. Multivariate analysis of the five factors showed a significant difference in the 1st VER (P = 0.002). The cutoff value for recanalization was a 1st VER of 5.8%. There were 162 cases with a VER ≥ 20% or higher, and the same analysis yielded similar results. Conclusion: The 1st VER was significantly correlated with recanalization of cerebral aneurysms requiring retreatment. In coil embolization of unruptured cerebral aneurysms, it is important to achieve an embolization rate of at least 5.8% using a framing coil to prevent recanalization.

Targeted transvenous embolization of a dural arteriovenous fistula at the jugular tubercle venous complex.

Background: Dural arteriovenous fistulas (dAVFs) occurring near the hypoglossal canal are rare. Detailed evaluation of vascular structures can identify shunt pouches at the jugular tubercle venous complex (JTVC) in the bone near the hypoglossal canal. Although the JTVC has several venous connections, including the hypoglossal canal, there have been no reports of transvenous embolization (TVE) of a dAVF at the JTVC using an approach route other than the hypoglossal canal. This report describes the first case of complete occlusion with targeted TVE using an alternative approach route in a 70-year-old woman presenting with tinnitus diagnosed with dAVF at the JTVC. Case Description: The patient had no history of head trauma or other preexisting conditions. Magnetic resonance imaging (MRI) showed no abnormal findings in the brain parenchyma. Magnetic resonance angiography (MRA) revealed a dAVF near the ACC. The shunt pouch was located in the JTVC, near the left hypoglossal canal, with feeders from the bilateral ascending pharyngeal arteries and occipital arteries, left meningohypophyseal trunk, and odontoid arch of the left vertebral artery. TVE was performed near the shunt pouch. Localized packing of the shunt point was achieved. The patient's tinnitus improved. Postoperative MRI showed disappearance of the shunt without any complications. No recurrence was observed on MRA 6 months after treatment. Conclusion: Our results suggest targeted TVE is an effective treatment for dAVFs at the JTVC.

Evaluation of a scoring system to assess proficiency in cerebral angiography for neuroendovascular surgery education.

Objective: Cerebral angiography is indispensable for endovascular neurosurgeons. However, there is no established system to evaluate the competency of trainees. We established a scoring system and statistically analyzed its characteristics. Methods: Endovascular neurosurgeons scored the operators of 177 cerebral angiography based on ten evaluation items. Preoperative explanation, device selection, and device assembly were classified as "preparation," communication with the patient, radiation protection and angiography system as "attention," and catheter operation, blood loss, procedure completion, and sheath insertion as "skill". The sum of the scores were compared using the Mann-Whitney test according to the status of the operator (trainee (TR), neurosurgeon (NS), or endovascular neurosurgeon (EVNS)). Results: The highest average for each item was 0.89 for communication, and the lowest was 0.68 for catheter operation. The mean ± standard deviation of the total score was 7.82 ± 2.02, and scores by status were 7.08 ± 2.12 for TR, 8.32 ± 1.35 for NS, and 9.33 ± 1.20 for EVNS with significant differences among each status (p < 0.05). The sum scores of the preparation, attention, and skill sections also showed significant differences between each status except between NS and EVNS in the preparation section and TR and NS in the skill section (p < 0.05). Conclusions: There were significant differences in the total score between statuses, suggesting that the scoring system may be an indicator of proficiency in cerebral angiography. It was suggested that dividing each item into preparation, attention, and skill sections may indicate the characteristics of proficiency.

Partially thrombosed distal posterior cerebral artery aneurysm treated with surgical trapping through occipital transtentorial approach assisted by endovascular coil embolization.

Background: Posterior cerebral artery (PCA) aneurysms are relatively rare. PCA aneurysms tend to be large, giant, fusiform, and partially thrombosed. Surgical treatments, such as neck clipping and trapping with or without bypass surgery, are curative treatments for thrombosed intracranial aneurysms. Few cases of surgical treatment of distal PCA aneurysms have been reported. We treated a partially thrombosed distal PCA aneurysm by trapping through the occipital transtentorial approach (OTA) assisted by endovascular coil embolization. Case Description: A 21-year-old woman presented with a sudden headache. Brain computed tomography, magnetic resonance imaging, and a cerebral angiogram revealed a partially thrombosed aneurysm in the left PCA P3 segment. Her headaches had improved once within several days, but reoccurred due to an enlarged thrombosed aneurysm. Endovascular coil embolization was performed to assist the surgery. The aneurysm and the distal artery of the aneurysm were embolized to interrupt the blood flow into the aneurysm. The following day, trapping of the aneurysm was performed through the OTA. Eventually, we performed aneurysm excision because trapping alone was considered to have the potential for regrowth of the aneurysm. The patient's postoperative course was uneventful. No recurrence of the aneurysm was observed at the 2-year follow-up. Conclusion: OTA could be useful for the treatment of distal PCA aneurysms, whereas coil embolization may support the surgical treatment of partially thrombosed intracranial aneurysms.

Factors related to high bifurcation level of common femoral artery.

BACKGROUND: Common femoral artery (CFA) puncture is performed for endovascular treatment. However, we sometimes experience branch punctures when the CFA bifurcation level is high. In this study, we examined the frequency of high CFA bifurcation level and related factors. METHODS: The CFA bifurcation level was identified in 100 patients, who underwent cerebral angiography or endovascular treatment by femoral artery (FA) puncture, on 191 sides. The height of the CFA bifurcation level was classified into three groups: normal, high, and very high. Age, gender, left-right difference, height, weight, body mass index, and comorbidities, including hypertension, dyslipidemia, and diabetes, were examined to determine the factors associated with high CFA bifurcation level. RESULTS: The normal, high, and very high groups were on 142, 35, and 14 sides, respectively. The high and very high groups, which were defined as high CFA bifurcation levels, accounted for 25% of all patients. Multivariate analysis revealed that the proportion of patients with high CFA bifurcation levels was higher in the elderly (p = 0.009) and those with a history of diabetes (p = 0.042). CONCLUSIONS: Approximately one-fourth of all patients undergoing cerebral angiography or endovascular treatment by FA puncture had high CFA bifurcation levels, which had a significant association with old age and history of diabetes. For urgent treatment, FA puncture might be performed at a higher level below the inguinal ligament if patients are elderly of those with a history of diabetes.

Minimum wall shear stress points and their underlying intra-aneurysmal flow structures of unruptured cerebral aneurysms on 4D flow MRI.

BACKGROUND AND PURPOSE: Minimum wall shear stress (Min-WSS) points may be associated with wall instability of unruptured cerebral aneurysms. We aimed to investigate the relationship between the locations of Min-WSS points and their underlying intra-aneurysmal flow structure patterns in unruptured cerebral aneurysms using four-dimensional (4D) flow magnetic resonance imaging (MRI). MATERIALS AND METHODS: Min-WSS points and the intra-aneurysmal flow structure patterns were identified in 50 unruptured aneurysms by 4D flow MRI. RESULTS: The Min-WSS points were located around a vortex core tip in 31 (62.0%) aneurysms and on an intra-bleb vortex center in 7 (14.0%). Sixteen (32.0%) aneurysms had the Min-WSS points on the aneurysmal apex, and in 24 (48.0%) were on the neck. The Min-WSS values of aneurysms with the Min-WSS points on an intra-bleb flow were significantly lower than those of the other groups (P = 0.030). Aneurysms with the Min-WSS points on the neck had significantly higher Min-WSS values than the other aneurysms (P = 0.008). CONCLUSIONS: The location of the Min-WSS point was corresponding to the vortex core or center in 76% of all aneurysms. The underlying intra-aneurysmal flow structure and location of the Min-WSS point affect the Min-WSS value. Further studies are needed to characterize Min-WSS points to identify aneurysms with a higher risk of wall instability.

Comparison of Endovascular Therapy for Ruptured Cerebral Aneurysm during Spasm and Nonspasm Period.

Objective Cerebral vasospasm complicates the treatment of aneurysmal subarachnoid hemorrhage, and the optimal timing of surgery for ruptured intracranial aneurysm diagnosed during the cerebral vasospasm period has been a matter of debate. This study aimed to clarify the differences in endovascular treatment outcomes between the timing of intervention during spasm and nonspasm. Methods and Materials We retrospectively reviewed 68 consecutive patients with ruptured cerebral aneurysms who underwent coil embolization between January 2016 and March 2021. Clinical presentations, radiographic findings, and outcomes were retrospectively reviewed and compared between patients who were treated at the time of spasm and nonspasm. Information regarding the following clinical characteristics was collected: age, sex, World Federation of Neurosurgical Societies (WFNS) grade on admission, aneurysm morphology, treatment result, and outcome. We defined from day 4 to day 14 as the timing of spasm, and vasospasm as more than 30% narrowing of the proximal anterior cerebral artery, middle cerebral artery, and internal carotid artery segment during the second examination compared with the first. The chi-squared test or Fisher's exact test were performed to evaluate the covariates for binary categorical dependent variables as appropriate, and nonnormal variables were compared using the Mann-Whitney U test. Results Ten patients (14.7%) underwent coil embolization at the time of vasospasm. Age, sex, WFNS grade, and aneurysm morphology were not different between the spasm and nonspasm groups. Additionally, there were no significant between-group differences in volume embolization ratio, procedure-related complications, occurrence of delayed cerebral ischemia, and outcome at discharge. Conclusion There were no significant between-group differences in treatment results and outcomes between the spasm and nonspasm groups. Endovascular treatment at the time of vasospasm could be the optimal treatment method for ruptured cerebral aneurysms.

Early Enteral Nutrition with High-Protein Whey Peptide Digestive Nutrients May Improve Prognosis in Subarachnoid Hemorrhage Patients.

Background and Objectives: Nutritional management in patients with subarachnoid hemorrhage (SAH) during the acute phase is important; however, there is no proper evidence or recommendations on the appropriate nutrients for early enteral nutrition. This study compared the influence the two different tube-feeding liquid diets for early enteral nutrition might have on the prognosis of patients with SAH. Materials and Methods: In a seven-year period, this single-center retrospective study included 245 patients with aneurysmal SAH who underwent craniotomy and aneurysm neck clipping and received enteral nutrition. The patients were divided into two groups according to the nutrient received: (1) high-protein whey peptide oligomeric formula diet (oligomeric group, 109 patients); and (2) high eicosapentaenoic acid-containing polymeric formula diet (polymeric group, 136 patients). The modified Rankin Scale (mRS) score at discharge was evaluated as the primary outcome. The presence or absence of diarrhea (watery stool and mushy stool) during the period from initiation of enteral nutrition to discharge from the stroke unit was also evaluated. Results: There were no significant differences in patient characteristics between groups. The time until initiation of enteral feeding in the oligomeric and polymeric groups was 2.8 ± 2.3 and 2.9 ± 2.2 days, respectively. The proportion of patients with mRS scores of 0-1 was significantly higher in the oligomeric group (25.7%) than in the polymeric group (14.7%) (p = 0.036), while the incidence of watery stool was significantly lower in the oligomeric group (15.8% to 34.3% in the polymeric group) (p = 0.003). Multivariate analyses confirmed that the oligomeric diet and the presence or absence of diarrhea significantly affected the mRS scores. Conclusions: The adoption of early enteral nutrition with high-protein whey peptide digestive nutrients might be associated with superior mRS scores at discharge and decreased diarrhea in patients with SA, indicating that the choice of nutrients might affect the outcome and prognosis.

Clinical Features of Ruptured Very Small Intracranial Aneurysms (<3 mm) in Patients with Subarachnoid Hemorrhage.

OBJECTIVE: Although small unruptured aneurysms rarely rupture, many patients with subarachnoid hemorrhage (SAH) have ruptured small, especially very small intracranial aneurysms (VSIAs; <3 mm) in clinical practice. We aimed to clarify the proportion and clinical features of patients with SAH with ruptured VSIAs. METHODS: 609 patients with ruptured intracranial aneurysms diagnosed at our institution from January 2012 to December 2018 were retrospectively analyzed. We classified patients into 2 groups based on ruptured aneurysm size: VSIAs or non-VSIAs (≥3 mm). We analyzed age, sex, location of aneurysms, World Federation of Neurological Surgeons grade on admission, treatment modality, and outcome at discharge. RESULTS: Among 609 patients, 103 had ruptured VSIAs. The proportion of young patients (age <40 years) was greater in the VSIA group than the non-VSIA group (10.7% vs. 3.6%, P = 0.002). The proportions of VSIAs located in the middle cerebral and vertebrobasilar arteries were relatively low and high, respectively (P = 0.002, 0.005). Significantly more patients with VSIAs than those with non-VSIAs were classified under World Federation of Neurological Surgeons grade I-III (70.9% vs. 56.3%, P = 0.006). Coil embolization was preferred for VSIAs (68.0% vs. 32.0%, P = 0.006). Outcomes were more favorable in the VSIA group than in the non-VSIA group. CONCLUSIONS: Small unruptured aneurysms rarely rupture; however, many patients with SAH have ruptured VSIAs in clinical practice. We observed that VSIA rates among ruptured aneurysms were fairly high. Age, posterior circulation location, and preferable outcome may be important clinical characteristics of ruptured VSIAs.

Predictive factors for bone flap infection after cranioplasty.

Bone flapinfection is often experienced as a complication of cranioplasty.The aim of this study was to investigate predictors of graft infection,including patient-specific and surgery-specific factors. We retrospectively reviewed cases at our institutionwho underwent cranioplasty following craniectomyfor traumatic brain injury, epidural hematoma, subdural hematoma, intracranial hemorrhage, cerebral infarction, subarachnoid hemorrhage, arteriovenous malformation, and bone flap infection after craniotomy. A total of 192 patients were included in this analysis.The graft infection rate was 8.3% (16/192).Smoking(odds ratio [OR] 3.09, 95% confidence interval [CI] 1.03-12.24; p = 0.04), allergy (OR 6.15, 95% CI 1.50-17.31; p < 0.01),and body temperature on postoperative day 1(OR 2.57, 95% CI 1.14-5.78; p = 0.02) were found to be independent predictors forgraft infection.Based on receiver operating characteristic analysis, a body temperature on postoperative day 1 higher than 38.0 °C was selected as the optimal cut-off value for predicting infection after cranioplasty. The sensitivity and specificity were 68% and 72%, respectively. Smoking, allergy, and body temperature on postoperative day 1predicted complications leading to graft infection. Patients with a fever of 38 °C or higher on day 1 after cranioplasty should be carefully monitored for graft infection.

Late complications of visual impairment and hydrocephalus after flow diverter-assisted coil embolisation for intracranial large aneurysm: a case report and literature review.

Large or giant paraclinoid aneurysms typically have good indication for flow diverter (FD) treatment. Here, we report a very rare case of a patient with an unruptured supraclinoid large aneurysm who underwent FD deployment with coil embolisation that resulted in delayed visual field defect (VFD) and hydrocephalus. A 75-year-old woman with a large right supraclinoid aneurysm presented with severe hemianopia in the right eye. She underwent FD deployment with coil embolisation of the aneurysm. However, permanent left visual field loss occurred four months after surgery. Magnetic resonance imaging (MRI) showed severe oedema surrounding the aneurysm along the optic tract. Inflammation led to postoperative hydrocephalus, requiring ventriculoperitoneal shunt placement. To the best of our knowledge, this is the first report of both a delayed VFD and hydrocephalus following FD treatment. In cases of FD treatment with coil embolisation for large paraclinoid aneurysms, clinicians should keep in mind that postoperative visual impairment or/and hydrocephalus may occur.

Hemodynamic factor evaluation using computational fluid dynamics analysis for de novo bleb formation in unruptured intracranial aneurysms.

BACKGROUND: Although bleb formation increases the risk of rupture of intracranial aneurysms, previous computational fluid dynamic (CFD) studies have been unable to identify robust causative hemodynamic factors, due to the morphological differences of prebleb aneurysm models and a small number of aneurysms with de novo bleb formation. This study investigated the influences of differences in the aneurysm-models and identify causative hemodynamic factors for de novo bleb formation. MATERIALS AND METHODS: CFD analysis was conducted on three aneurysm models, actual prebleb, postbleb, and virtual prebleb models of two unruptured aneurysms with de novo bleb formation. A new multipoint method was introduced in this study. We evenly distributed points with a 0.5-mm distance on the aneurysm surface of the actual prebleb models (146 and 152 points in the individual aneurysm, respectively), and we statistically compared hemodynamics at the points in the areas with and without bleb formation (19 and 279 points, respectively). RESULTS: Visually, blebs formed on an aneurysm surface area with similar hemodynamic characteristics in the actual and virtual prebleb models. Statistical analysis using the multipoint method revealed that the de novo bleb formation area was significantly correlated with high pressure (p < 0.001), low wall shear stress (WSS) (p < 0.001), and the center of divergent WSS vectors (p = 0.025). CONCLUSIONS: De novo bleb formation in intracranial aneurysms may occur in areas associated with the combination of high pressure, low WSS, and the center of divergent WSS vectors. The multipoint method is useful for statistical analysis of hemodynamics in a limited number of aneurysms.

Morphological factors affecting vortex core instability on 4D flow MRI of unruptured cerebral aneurysms.

OBJECTIVE: The spatiotemporal instability of intra-aneurysmal vortex flow may be associated with unruptured cerebral aneurysm rupture. We identified morphological factors that affect intra-aneurysmal vortex core patterns classified based on the instability on four-dimensional (4D) flow magnetic resonance imaging (MRI) and determined cutoff values for the factors to discriminate unstable core patterns. METHODS: We classified vortex core patterns of 40 unruptured aneurysms on 4D flow MRI into stable, stable with a flapping tip, continuously deforming wave-or-coil-like, and non-visualized. We statistically compared nine morphological parameters among aneurysm groups with individual patterns. RESULTS: The vortex cores were stable (n = 16) (group A), stable with a flapping tip (n = 15) (group B), wave-or-coil-like (n = 7) (group C), and non-visualized (n = 2) (group D). Since there were no statistically significant differences between groups A and B, we compared the difference between the groups A and B and the other groups. Multivariate logistic regression analyses found that size ratio (SR) was an only independently significant parameter (p < 0.05). The receiver-operating characteristic analysis between groups A and B and group C and between groups A and B and groups C and D revealed that the area under the curve value for SR was the highest (0.829 [95% CI, 0.642-1.0]; 0.867 [95% CI, 0.715-1.0], respectively) among morphological factors; the cutoff value for SR was 1.72 (specificity 0.714, sensitivity 0.756; specificity 0.806, sensitivity 0.778, respectively). CONCLUSION: SR was an independent morphological factor contributing to vortex core instability based on the vortex core patterns on 4D flow MRI.Abbreviations: CFD: computational fluid dynamics; 3D: three-dimensional; 4D: four-dimensional; MRI: magnetic resonance imaging; MRA: magnetic resonance angiography; ICA: internal carotid artery; AR: aspect ratio; SR: size ratio; CI: confidence interval; AUC: area under the curve; ROC: receiver-operating characteristic.

Multiple Endovascular Treatments for Hemorrhagic Cerebral Proliferative Angiopathy: A Case Report.

Cerebral proliferative angiopathy (CPA) is a rare vascular abnormality characterized by transdural supply, stenoses of feeding arteries, and intermingled normal brain parenchyma in abnormal vessels. CPA is often regarded as a separate entity from "classical" brain arteriovenous malformations in angioarchitecture, natural history, clinical presentation, and treatment. Bleeding from CPA is uncommon, but once bleeding occurs, the risk of rebleeding is high. Herein, we describe a case of cerebral hemorrhage caused by CPA. We performed two different endovascular treatments: partial embolization with glue for a ruptured aneurysm and coil embolization for an unruptured growing aneurysm. To our knowledge, this is the first report of serial endovascular treatments for hemorrhagic CPA that included a ruptured aneurysm and a growing unruptured aneurysm.