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Background and Purpose: Flow diversion is an established method to treat complex intracranial aneurysms. The natural history of flow-diversion treatment failure resulting in aneurysm remnants is not well-defined. We aimed to delineate the clinical and angiographic features of this entity., Materials and Methods: Review of a prospectively maintained Pipeline Embolization Device data base from inception to October 2017 was performed for aneurysms that demonstrated residual filling on follow-up imaging. Procedural and follow-up clinical details were recorded. Independent, blinded, angiographic assessment of occlusion was performed on the basis of the O'Kelly-Marotta scale. Aggregated outcomes were analyzed using the Fisher exact and Mann-Whitney U tests for categoric and continuous variables, respectively (statistical significance, α = .05)., Results: During the study period, 283 sequential patients were treated; 87% (246/283) were women. The median patient age was 55 years (interquartile range, 47-65 years). Six-month follow-up imaging was available in 83.7% (237/283) of patients, which showed 62.4% (148/237) complete occlusion (class D, O'Kelly-Marotta grading scale). Adjunctive coiling ( P = .06), on-label Pipeline Embolization Device use ( P = .04), and multiple device constructs ( P = .02) had higher rates of complete occlusion at 6 months. Aneurysm remnants were identified in 25 cases on long-term follow-up imaging (median, 16 months; interquartile range, 12-24 months). No patient with an aneurysm remnant after flow diversion presented with delayed rupture or other clinical sequelae, with a median clinical follow-up of 31 months (interquartile range, 23-33 months)., Conclusions: Aneurysm remnants after flow diversion are infrequent with minimal clinical impact. When appropriate, the presence of overlapping devices and possibly adjunctive coiling may result in higher rates of complete occlusion., (© 2019 by American Journal of Neuroradiology.)

Background and Purpose: Endovascular reconstruction and flow diversion by using the Pipeline Embolization Device is an effective treatment for complex cerebral aneurysms. Accurate noninvasive alternatives to DSA for follow-up after Pipeline Embolization Device treatment are desirable. This study evaluated the accuracy of contrast-enhanced time-resolved MRA for this purpose, hypothesizing that contrast-enhanced time-resolved MRA will be comparable with DSA and superior to 3D-TOF MRA., Materials and Methods: During a 24-month period, 37 Pipeline Embolization Device-treated intracranial aneurysms in 26 patients underwent initial follow-up by using 3D-TOF MRA, contrast-enhanced time-resolved MRA, and DSA. MRA was performed on a 1.5T unit by using 3D-TOF and time-resolved imaging of contrast kinetics. All patients underwent DSA a median of 0 days (range, 0-68) after MRA. Studies were evaluated for aneurysm occlusion, quality of visualization of the reconstructed artery, and measurable luminal diameter of the Pipeline Embolization Device, with DSA used as the reference standard., Results: The sensitivity, specificity, and positive and negative predictive values of contrast-enhanced time-resolved MRA relative to DSA for posttreatment aneurysm occlusion were 96%, 85%, 92%, and 92%. Contrast-enhanced time-resolved MRA demonstrated superior quality of visualization (P = .0001) and a higher measurable luminal diameter (P = .0001) of the reconstructed artery compared with 3D-TOF MRA but no significant difference compared with DSA. Contrast-enhanced time-resolved MRA underestimated the luminal diameter of the reconstructed artery by 0.965 ± 0.497 mm (27% ± 13%) relative to DSA., Conclusions: Contrast-enhanced time-resolved MRA is a reliable noninvasive method for monitoring intracranial aneurysms following flow diversion and vessel reconstruction by using the Pipeline Embolization Device., (© 2014 by American Journal of Neuroradiology.)

Background and Purpose: Denser coil packing in intracranial aneurysms is believed to result in lower recanalization rates. Hydrogel-coated expandable coils (HydroCoil) improve volumetric packing of aneurysms in animal models and clinical studies, but data from large clinical series are limited. The objective of this retrospective analysis was to analyze immediate and follow-up angiographic results as well as complications in a large consecutive series of patients treated with HydroCoils at a single institution., Materials and Methods: Retrospective analysis was performed of periprocedural complications, immediate and follow-up angiograms, and retreatments of the first 200 consecutive intracranial aneurysms treated at Emory University Hospital., Results: One hundred eighty-seven patients with 200 intracranial aneurysms were treated with HydroCoils during a 3-year period. Immediate angiograms showed complete aneurysmal obliteration in 58.4% of small aneurysms and 42.7% of large aneurysms. Periprocedural complications included early rebleeding and thromboembolic events resulting in permanent neurologic morbidity and mortality in 6% of cases. Follow-up angiography during an average of 16.3 months demonstrated recanalization in 17.7% of small aneurysms and 28.6% of large aneurysms, requiring retreatment in 6.3% and 19.0% of cases, respectively. During the same time period, there was delayed angiographic improvement in aneurysm obliteration in 26.6% of small aneurysms and 26.2% of large aneurysms., Conclusions: First-generation HydroCoil treatment of intracranial aneurysms has a favorable rate of recanalization compared with most large series of pure platinum coils with similar complication rates.

A three-dimensional Guglielmi detachable coil (3D-GDC) has been developed that is designed specifically to bridge the neck of an aneurysm with coil loops, thereby facilitating retention of additional coils placed within the aneurysm. Nine wide-necked cerebral aneurysms were successfully embolized using the 3D-GDC, provided that the dome-to-neck ratio was 1.5 or greater.

Endovascular therapy for intracranial aneurysms has evolved since Serbinenko pioneered embolisation with latex balloons in the 1970s. The focus of modern endovascular therapy has shifted to the use of Guglielmi Detachable Coils (GDC; Boston Scientific Corporation, Natick, MA, USA) which are retrievable until the operator is satisfied with placement and they are detached. GDC therapy has been shown to be most efficacious in smaller aneurysms with relatively large dome:neck ratios which allow maximal coil packing within the aneurysm lumen. Wide neck aneurysms with dome:neck ratios of less than 2.0 and large aneurysms have a significantly lower incidence of complete treatment, with higher rates of repeat rupture following GDC therapy. The geometry of wide neck aneurysms is less favourable for retention of coils within the aneurysm lumen, resulting in greater risk of parent vessel compromise from coil herniation and difficulty obtaining maximal coil packing. This chapter will summarise GDC therapy for intracranial aneurysms including newer techniques designed to address the problem of wide neck aneurysms., (Copyright 2000 Harcourt Publishers Ltd.)

Purpose: To develop a rabbit model of an intracranial bifurcation aneurysm to test new endovascular therapies., Materials and Methods: An experimental aneurysm model was created in rabbits by means of endovascular balloon occlusion of the left common carotid artery, which created an aneurysm at the bifurcation formed by the aortic arch and the brachiocephalic trunk. A total of 18 aneurysms were created. In eight rabbits, the aneurysms were incubated with intraluminal elastase to induce degeneration of the elastic laminae. The animals were followed up with angiography for as long as 3 months. The animals were sacrificed at various times, and histologic evaluation of the aneurysm was performed., Results: Ten aneurysms created without elastase infusion were all very small or completely closed at 1-3 months. Six aneurysms created with elastase infusion had long-term patency (two were patent at 1 month and four, at 3 months). The elastase aneurysms had a mean width of 3 mm (range, 2-3.5 mm) and a mean length of 5 mm (range, 3-7 mm). Histologic evaluation revealed destruction of the normal elastin layers, which allowed the artery to become aneurysmal., Conclusion: This aneurysm model re-created the hemodynamic forces and size of human cerebral bifurcation aneurysms and maintained the integrity of the endothelium. The creation of the aneurysms was rapid, reliable, and reproducible.

Background and Purpose: A well-defined complication rate of cerebral angiography in patients with subarachnoid hemorrhage (SAH), cerebral aneurysm, and arteriovenous malformation (AVM) would be useful to physicians making decisions regarding the imaging of these patients. We sought to define a statistically significant complication rate through meta-analysis of prospective studies in the literature., Methods: Meta-analysis of 3 published prospective studies of complications in cerebral angiography was performed to specifically define the risk of cerebral angiography in patients presenting with SAH, cerebral aneurysm, and AVM. The complication rates for cerebral angiography in patients with SAH and AVM/aneurysm without SAH were compared with the complication rates in patients who underwent cerebral angiography for transient ischemic attack (TIA)/ischemic stroke with use of the Fisher exact test., Results: The combined risk of permanent and transient neurological complication was significantly lower in patients with SAH compared with patients with TIA/stroke (1.8% versus 3.7%; P=0.03). The combined risk of permanent and transient neurological complication was significantly lower in patients with aneurysm/AVM without SAH compared with patients with TIA/stroke (0.3% versus 3.7%; P=0.001). When the patients with SAH and cerebral aneurysm/AVM were combined, the overall risk of permanent and transient neurological complication was significantly lower than for the TIA/stroke patients (0.8% versus 3.0%; P=0.001), as was the risk of permanent neurological complication (0.07% versus 0.7%; P=0.004)., Conclusions: The risk of permanent neurological complication associated with cerebral angiography in patients with SAH, cerebral aneurysm, and AVM is quite low (0.07%). This risk is lower than previously recognized.

We report two cases of distal cerebral aneurysms that were treated by parent artery occlusion with short Guglielmi detachable coils (GDCs). One patient had a presumed mycotic aneurysm of the distal left posterior cerebral artery, and the other had a partially clipped aneurysm of the distal right anterior inferior cerebellar artery that had hemorrhaged. Short GDCs allow controlled, accurate occlusion of the parent artery at the aneurysmal neck.

Object: The aim of this study was to determine the prevalence of cerebral saccular aneurysms in patients with carotid artery and/or vertebral artery (VA) fibromuscular dysplasia (FMD)., Methods: A metaanalysis was performed using data from 17 previously reported series of patients with internal carotid artery (ICA) and/or VA FMD that included information on the prevalence of cerebral aneurysms. In addition, the authors retrospectively evaluated their own series of 117 patients with ICA and/or VA FMD to determine the prevalence of cerebral aneurysms. The metaanalysis of the 17 earlier series, which included 498 patients, showed a 7.6 +/- 2.5% prevalence of incidental, asymptomatic aneurysms in patients with ICA and/or VA FMD. In the authors' series of patients with FMD, 6.3 +/- 4.9% of patients harbored an incidental, asymptomatic aneurysm. When the authors' series was combined with those included in the metaanalysis, the prevalence was found to be 7.3 +/- 2.2%. The prevalence of aneurysms in the general population would have to be greater than 5.6% for there to be no statistically significant difference (chi-square test, p < 0.05) when compared with this 7.3% prevalence in patients with FMD., Conclusions: The prevalence of intracranial aneurysms in patients with cervical ICA and/or VA FMD is approximately 7%, which is not nearly as high as the 21 to 51% prevalence that has been previously reported.

Purpose: We calculated the incremental cost-utility ratio for Guglielmi detachable coil (GDC) embolization versus no therapy for unruptured intracranial aneurysms considered inappropriate for surgical clipping procedures., Methods: Decision tree and Markov analyses that employ cohort simulation were applied to determine the incremental cost-utility ratio of GDC embolization versus no therapy for unruptured cerebral aneurysms. Clinical values required as input data were estimated from the literature for the following variables: relative frequencies of complete aneurysmal occlusion, partial aneurysmal occlusion, and attempted coiling (no coils detached); morbidity and mortality of GDC embolization; frequency, morbidity, and mortality of spontaneous aneurysmal rupture in untreated and GDC-embolized aneurysms; annual rate of recanalization of GDC-embolized aneurysms; quality of life when knowingly living with untreated or GDG-embolized aneurysms and of living with fixed neurologic deficit; costs of GDC embolization, spontaneous aneurysmal rupture, stroke, and rehabilitation; and discount rate. Cost-utility ratios below $50000 per quality-adjusted life year saved were considered acceptable. Sensitivity analyses were performed for all relevant input variables., Results: Baseline input values resulted in acceptable cost-utility ratios for GDC embolization of unruptured intracranial aneurysms. These ratios remained within acceptable limits across wide ranges of various input parameters. Cost-effectiveness was markedly affected by the natural course of unruptured, untreated aneurysms; rates of spontaneous rupture greater than 2% per year resulted in favorable cost-utility ratios that were relatively unaffected by variation in GDC efficacy, while rates of rupture less than 1% per year resulted in unfavorable ratios that were highly dependent on GDC efficacy. Many of the GDC efficacy indexes, such as rate of failed coiling, early recanalization, and progressive aneurysmal thrombosis, have mild effects on the cost-utility ratios. GDC complication rate as well as life expectancy had moderate effects on the analysis. The influence of late aneurysmal recanalization was mild unless high rates of rupture for partially coiled aneurysms were applied. Suboptimal clip placement resulting from the presence of GDC coils within a ruptured aneurysm had no demonstrable consequence on cost-utility ratios., Conclusions: The single most influential variable determining the cost-effectiveness of GDC embolization in our analysis was the natural course of untreated aneurysms. Other important variables included GDC-related morbidity and life expectancy at the time of GDC embolization.

Purpose: To optimize parameters with computed tomographic angiography for the detection of cerebral aneurysms., Materials and Methods: Model aneurysms were placed randomly at various branch points and scanned multiple times with spiral technique. The final analysis included 63 branch points and 22 aneurysms. Each spiral scan used a different parameter combination. Collimation ranged from 1.5 to 4.0 mm and pitch ranged from 1:1 to 1.5:1. Images were constructed with shaded surface display (SSD) and maximum intensity projection (MIP) algorithms and were interpreted by three readers for the presence or absence of aneurysm., Results: The receiver operating characteristic (ROC) curve area for 1.5-mm collimation was greater than those of 3- or 4-mm collimation (P < .01 and P < .001, respectively). There was no statistically significant difference in the ROC curve areas between 3- and 4-mm collimation (P = .37). There was no statistically significant decrease in ROC curve area when increasing pitch from 1:1 to 1.5:1 for any value of collimation (P = .96). For all parameter combinations the ROC curve areas for SSD images was greater than that of MIP images (P < .0001)., Conclusion: For cerebral aneurysm detection, narrow collimation is superior to wider collimation. Mild increases in pitch do not substantially degrade diagnostic accuracy. SSD offers improved diagnostic accuracy over MIP display in this model.

Carotid-cavernous aneurysms account for between 1.9% and 9.0% of intracranial aneurysms. Entirely intercavernous aneurysms are believed to have a relatively benign course, with cranial nerve findings or headache being the usual initial symptomatology; however, subarachnoid hemorrhage or carotid-cavernous fistula formation can result from rupture. Over the past 15 years endovascular parent artery occlusion has essentially replaced surgical carotid occlusion as the treatment of choice. The authors describe a series of 39 consecutive patients at the University of Virginia Health Sciences Center who underwent endovascular treatment of a carotid-cavernous aneurysm. Aggressive invasive hemodynamic monitoring and maintenance of a state of normo- to mild hypervolemia in the asymptomatic patient was used throughout the periprocedural period. Rapid institution of hypervolemic-hypertensive therapy can reverse early neurological deficits related to hypoperfusion in these patients. Only one individual managed with this protocol developed neurological deficits not reversible with hypertensive-hypervolemic therapy. Heparin therapy was administered for 48 hours after occlusion, with patients receiving subsequent aspirin therapy for 6 months to combat distal embolism secondary to thrombosis. Long-term complications were not seen in patients receiving aneurysm trapping; however, two individuals with proximal carotid occlusion developed late optic neuropathy and one had recurrent transient ischemic attacks that ceased with supraclinoidal carotid clipping.

In a multicenter study, 120 patients with intracranial aneurysms presenting a high surgical risk were treated using electrolytically detachable coils and electrothrombosis via an endovascular approach. The results of treatment in patients with posterior fossa aneurysms (42 patients with 43 aneurysms) are presented. The most frequent clinical presentation was subarachnoid hemorrhage (24 cases). The clinical follow-up periods ranged from 1 week to 18 months. Complete aneurysm occlusion was obtained in 13 of 16 aneurysms with a small neck and in four of 26 wide-necked aneurysms. A 70% to 98% thrombosis of the aneurysm was achieved in 22 of 26 aneurysms with a wide neck and in three of 16 small-necked aneurysms. One aneurysm could not be treated due to a technical complication. Two cases required postprocedural surgical clipping of a residual aneurysm. One patient (originally in Hunt and Hess Grade V) experienced procedural rupture of the aneurysm requiring an emergency parent artery occlusion. He eventually died 5 days later. Another patient (originally in Grade IV) had coil migration and posterior cerebral artery territory ischemia. A third patient developed a permanent neurological deficit (hemianopsia) after complete occlusion of a wide-necked basilar bifurcation aneurysm. One patient, harboring an inoperable giant basilar bifurcation aneurysm, died from aneurysm bleeding 18 months after partial occlusion. Overall morbidity and mortality rates related to treatment were 4.8% (two cases) and 2.4% (one case), respectively (2.6% and 0% if considering only patients in Hunt and Hess Grades I, II, and III). It is suggested that this technique is a viable alternative in the management of patients with posterior fossa aneurysms associated with high surgical risk. Longer angiographic and clinical follow-up study is necessary to determine the long-term efficacy of this recently developed endovascular occlusion technique. Close postoperative angiographic and clinical monitoring of patients with wide-necked subtotally occluded aneurysms is mandatory to check for potential aneurysmal recanalization, regrowth, and rupture.

Fifteen patients with high-risk intracranial saccular aneurysms were treated using electrolytically detachable coils introduced via an endovascular approach. The patients ranged in age from 21 to 69 years. The most frequent clinical presentation was subarachnoid hemorrhage (eight cases). Considerable thrombosis of the aneurysm (70% to 100%) was achieved in all 15 patients, and preservation of the parent artery was obtained in 14. Although temporary neurological deterioration due to the technique was recorded in one patient, no permanent neurological deficit was observed in this series and there were no deaths. It is believed that this new technology is a viable alternative in the management of patients with high-risk intracranial saccular aneurysms. It may also play an important role in the occlusion of aneurysms in the acute phase of subarachnoid hemorrhage.

Intraoperative digital subtraction angiography using commercially available equipment was employed to confirm the precision of the surgical result in 105 procedures for intracranial aneurysms or arteriovenous malformations (AVM's). Transfemoral selective arterial catheterization was performed in most of these cases. A radiolucent operating table was used in all cases, and a radiolucent head-holder in most. In five of the 57 aneurysm procedures, clip repositioning was required after intraoperative angiography demonstrated an inadequate result. In five of the 48 AVM procedures, intraoperative angiography demonstrated residual AVM nidus which was then located and resected. In two cases intraoperative angiography failed to identify residual filling of an aneurysm which was seen later on postoperative angiography, and in one case the intraoperative study failed to demonstrate a tiny residual fragment of AVM which was seen on conventional postoperative angiography. Two complications resulted from intraoperative angiography: one patient developed aphasia from cerebral embolization and one patient developed leg ischemia from femoral artery thrombosis. This technique appears to be of particular value in the treatment of complex intracranial aneurysms and vascular malformations.