Hemorrhage from a recurrent aneurysm is a major concern after coiling for intracranial aneurysms. We aimed to identify aneurysm recurrence patterns associated with hemorrhage. We investigated ...radiological data of patients who underwent coiling for intracranial aneurysms in 2008-2016 and were followed-up for at least 6 months. Aneurysm recurrence patterns were classified as: type â , enlargement of aneurysm neck; type II, recurrent cavity within the coil mass; type â¢, recurrent cavity along the aneurysm wall; and type â£, formation of a daughter sac. We evaluated the incidence of various recurrence patterns with or without hemorrhage. Of the 173 aneurysms included in the study (mean follow-up period, 32 months; range, 6-99 months), 22 (13%) recurred and required re-treatment. The recurrence patterns included type â , II, â¢, and ⣠in 7 (4%), 4 (2%), 9 (5%), and 2 (1%) cases, respectively. Most of the type â , II, and ⢠recurrences occurred within 1 year, and type ⣠occurred at 7 years after coiling. Three aneurysms exhibited hemorrhage, one with type ⢠and two with type ⣠pattern. The two aneurysms with type ⣠recurrence initially occurred as type â ; however, the recurrent neck enlarged gradually, resulting in new sac formation. We recommend prompt re-treatment for aneurysms recurring with type ⢠or ⣠patterns, as such patterns were associated with hemorrhage. Furthermore, we need a special care to type â recurrence with enlargement of recurrent neck because this specific pattern may develop to type â£.
Purpose
A previous study on computational fluid dynamics reported that a high pressure difference (PD) at the surface of a coil mass is a strong predictor of aneurysm recurrence after coil ...embolization. PD was calculated using a virtual post-coiling model (VM), created by manually cutting the aneurysm by the flat plane from an anatomic model created with pre-coil embolization data; however, its credibility has not been fully evaluated. This study aims to clarify whether PD values calculated using the post-coiling model, which reflects the actual coil plane, are a strong predictor of aneurysm recurrence.
Methods
Fifty internal carotid artery aneurysms treated with endovascular coil embolization were analyzed (7 recanalized, 43 stable). We created and subjected two post-coiling models, namely, VM and the real post-coiling model (RM), constructed from the post-coil embolization data. The relationship between PD and aneurysm recurrence was examined using these models. PD and its constituent three parameters were compared between VM and RM.
Results
PD values calculated using RM showed significantly higher aneurysm recurrence in recurrence group than stable group (
p
< 0.001), and multivariate analysis showed that PD in RM (
p
= 0.02; odds ratio, 36.24) was significantly associated with aneurysm recurrence. The receiver operating characteristic analysis revealed that PD values accurately predicted aneurysm recurrence (area under the curve, 0.977; cutoff value, 3.08; sensitivity, 100%; specificity, 97.7%). All four parameters showed a significant correlation with VM and RM (
p
< 0.001).
Conclusion
Use of PD to predict recurrence after coil embolization can be clinically relevant.
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.
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.
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.
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).
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
Although the inflow hemodynamics of cerebral aneurysms are key factors in their rupture and recurrence after endovascular treatments, the most available method for inflow hemodynamics evaluation ...remains unestablished. We compared the efficacy of inflow hemodynamics evaluation using computational fluid dynamics (CFD) analysis and that using four-dimensional (4D) flow magnetic resonance imaging (MRI).
In 23 unruptured cerebral aneurysms, the inflow hemodynamics was evaluated using both CFD and 4D flow MRI. The evaluated parameters included visually classified inflow jet patterns, the inflow rate ratio (the ratio of the inflow rate at the aneurysmal orifice to the flow rate in the proximal parent artery), and the velocity ratio (the ratio of the inflow velocity to the velocity in the proximal parent artery). The Shapiro-Wilk test was used to assess the normality of variable data, and logarithmic transformation was performed for variables with non-normal distributions. Data analysis was performed using Pearson correlation analyses and the chi-square test.
There was a significant correlation between inflow jet patterns evaluated by CFD and 4D flow MRI (p = 0.008). Moreover, there was a strong correlation between the inflow rate ratios evaluated by CFD and 4D flow MRI (r = 0.801; p <0.001). Furthermore, there was a moderate correlation between the velocity ratios measured by CFD and 4D flow MRI (r = 0.559; p = 0.008).
Inflow hemodynamics evaluated by CFD analysis and 4D flow MRI showed good correlations in inflow jet pattern, inflow rate ratio, and velocity ratio.
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.
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.
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).
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.
Objective: We investigated the usefulness of 2D-perfusion analysis for the evaluation of cerebral blood flow in unilateral cervical internal carotid artery stenosis.Methods: We conducted a ...2D-perfusion analysis during cerebral angiography and 123I-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) for unilateral cervical internal carotid artery stenosis without contralateral stenosis. The relationship between the ratio of the lesion side to the normal side in the parameters obtained by 2D-perfusion and the value calculated by stereotactic extraction estimation (SEE) analysis of SPECT was statistically examined.Results: The ratios of the lesion side to the normal side regarding the peak arrival time (AT; time to peak TTP) of the contrast agent and the mean filling time (mean transit time MTT) of the contrast agent in 2D-perfusion significantly correlated with the area of Stage II and increase ratio (I.R) ≤30% in the SEE analysis (p = 0.002, 0.003).Conclusion: 2D-perfusion analysis can be used to estimate the extent of impaired cerebrovascular reserve (CVR) area in unilateral internal carotid artery stenosis.
Background:
Treatment of cervical internal carotid artery (ICA) stenosis has contributed to the improvement of ocular ischemic syndrome. However, there have been few cases of visual impairment caused ...by ocular ischemic syndrome due to intracranial ICA stenosis, which improved through intracranial stent placement.
Case Description:
A 76-year-old man presented with right-sided paralysis. Radiographic examination revealed severe stenosis of the left intracranial ICA (distal cavernous-infraclinoid portion) and a watershed infarction of the left cerebral hemisphere. Conservative therapy including antiplatelet drugs was initiated, but severe visual acuity disturbance in his left eye occurred 1 month after onset. The antegrade ocular artery flow recovered after urgent intracranial stent placement, and his vision improved immediately after the procedure.
Conclusion:
Visual impairment presenting as ocular ischemic syndrome can occur due to severe stenosis of the intracranial ICA, and treatment of these lesions could improve the symptoms.
Background:
Excellent treatment outcomes using a pipeline embolization device (PED) have been reported. However, several limitations exist. For example, patients must receive antiplatelet therapy for ...at least several months, and few alternative treatments exist except for inserting additional flow diverter stents in cases where aneurysm obliteration is not obtained.
Case Description:
A 67-year-old female suffered from an asymptomatic large aneurysm of the left paraclinoid internal carotid artery (ICA). She underwent endovascular coil embolization, but coil compaction was confirmed at 2-year follow-up. A PED was inserted as an additional treatment. Unfortunately, the patient was required to discontinue antiplatelet therapy to undergo orthopedic surgery for her severe osteoarthritis of the knee. However, surveillance imaging performed 2 years after insertion of the PED revealed persistent filling into the aneurysm, and we could not stop the antiplatelet therapy to proceed with orthopedic surgery. Therefore, we performed ICA trapping with extracranial-intracranial high-flow bypass to cease antiplatelet therapy promptly. Antiplatelet therapy was completed 3 months after the rescue surgery, and the patient underwent orthopedic surgery.
Conclusion:
The authors describe a case of failure of complete obliteration after treatment using a PED, which required cessation of antiplatelet therapy to receive orthopedic surgery. Although safety and efficacy of PED treatment have been reported, we must consider the possibility of other diseases requiring discontinuation of antiplatelet therapy after PED embolization.
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