Flow diverter for endovascular treatment of intracranial mirror segment internal carotid artery aneurysms.

BACKGROUND: To evaluate the feasibility and efficacy of the pipeline embolization device in the treatment of unruptured intracranial mirror segment aneurysms. METHODS: Out of a total of 338 subjects, 14 were identified harboring a total of 32 internal carotid artery mirror segment aneurysms that were treated with the pipeline embolization device and were consecutively enrolled into our study. We collected data on patient demographics, modified Rankin scale (mRS) at admission, aneurysm characteristics, clinical outcome at discharge, 3-9 and at 12-18 months as well as angiography results at follow-up. RESULTS: Patients' mean age was 52.9 years; baseline mRS was 0 in all subjects. Pipeline embolization device placement was successful in all cases. Post-treatment mRS remained 0 in 13/14 patients. One patient experienced a small intraparenchymal hemorrhage and subarachnoid hemorrhage, associated with a frontoparietal infarction resulting in right upper extremity weakness and aphasia (post-treatment mRS 3). His mRS evaluation remained stable at the 3-9-month follow-up. Three to 9-month follow-up angiography (13/14 subjects) showed complete aneurysm occlusion in 24/30 aneurysms (80%), near complete and partial occlusion in three of 30 (10%) aneurysms each. At the 9-month follow-up, one patient experienced a complete occlusion of the anterior temporal artery branch but did not present with any clinical deficits. No mRS changes were encountered over a median 6-month follow-up period. Mid-term follow-up angiography (12-18 months) available in eight of 14 subjects showed complete aneurysm occlusion in all patients. Mild intimal hyperplasia was observed in one patient. CONCLUSIONS: Flow diversion technology can be used for the treatment of unruptured mirror segment aneurysms in selected patients.

Bypass for Innominate Artery Occlusive Disease.

The innominate artery, also known as the brachiocephalic artery, is the first vessel off the aortic arch and provides blood to the right arm, neck, and head. Occlusion of the innominate artery can be treated with endarterectomy, angioplasty, stenting, and bypass grafting. Bypass grafting describes a surgical procedure during which a bypass from the ascending aorta to the innominate artery is created. Our case depicts a patient post innominate artery bypass graft with a less commonly encountered postsurgical anatomy.

Pipeline Embolization Device for Pericallosal Artery Aneurysms: A Retrospective Single Center Safety and Efficacy Study.

BACKGROUND: Pericallosal artery aneurysm treatment may be challenging using traditional endovascular techniques. OBJECTIVE: To demonstrate the feasibility, efficacy, and safety of endovascular treatment of pericallosal artery aneurysm using flow diverters. METHODS: We performed a retrospective review of our institutional database from July 2013 through July 2016 and identified 7 subjects with a pericallosal artery aneurysm treated with the Pipeline embolization device (ev3 Neurovascular, Medtronic, Dublin, Ireland) and at least 1 follow-up angiogram. Technical feasibility, procedural complication, angiographic results, and clinical outcome were evaluated. RESULTS: Placement of the Pipeline embolization device was successful in all cases without evidence of procedural complication. Five out of 7 subjects showed a complete aneurysm occlusion at 6- to 12-mo follow-up angiogram. The 2 subjects with persistent aneurysm filling showed decreased aneurysm sac volume on follow-up angiograms (96% and 60%). There was no evidence of in-implant stenosis or intimal hyperplasia. No thromboembolic or hemorrhagic complications were seen during the follow-up period. Only 1 patient had a transient change in Modified Rankin scale score from baseline as a result of different unrelated procedure. CONCLUSION: Our preliminary results demonstrate feasibility of the use of flow diverter stent for treatment of aneurysms of the pericallosal artery with rate of aneurysm occlusion comparable to literature and without evidence of increased procedural or short-term morbidity. A long-term and larger cohort study is needed to validate our findings.

Two-year single-center experience with the 'Baby Trevo' stent retriever for mechanical thrombectomy in acute ischemic stroke.

OBJECTIVE: To evaluate the safety and efficacy of the 'Baby Trevo' (Trevo XP ProVue 3×20 mm Retriever) stent retriever for large vessel occlusions (LVOs) in acute ischemic stroke (AIS). MATERIALS AND METHODS: We retrospectively analyzed our stroke database and included all patients treated with the Baby Trevo for distal LVOs in AIS. Patient gender, mean age, vascular risk factors, National Institutes of Health Stroke Scale (NIHSS) score at presentation, and modified Rankin Scale (mRS) score at baseline and 90-day follow-up were documented. Reperfusion rates for the vessels treated were recorded using the Thrombolysis in Cerebral Infarction (TICI) classification. Occurrence of vasospasm and new or evolving infarcts in the treated vascular territory was documented. RESULTS: Thirty-five subjects with a mean NIHSS score of 18 were included. The Baby Trevo device was used in 38 branches of the anterior and posterior circulations. TICI 2b/3 blood flow was restored after one single pass in 20/38 (52.6%) and after two or three passes in 11 vessels. The remaining vessels required either more than three passes, showed less than a TICI 2b/3 reperfusion (n=3), or demonstrated failure to retrieve the clot (n=4). TICI 2b/3 reperfusion was achieved in 30 patients (85.7%). No vessel injuries, rupture, or significant vasospasm were seen. Overall, a mRS score of ≤2 was seen in 56.5% of the subjects successfully treated with the Baby Trevo at 90 days and in 81.3% of surviving patients; seven patients died (20%). CONCLUSIONS: Our preliminary data suggest that the 'Baby Trevo' achieves a high recanalization rate without any significant risk. Larger cohort studies are needed to validate the clinical benefit.

Use of self-expanding stents for better intracranial flow diverter wall apposition.

Background Flow diverter (FD) malapposition is associated with stroke-related complications. We document the use of self-expanding nitinol stents to remove/reduce the ledge of a FD deployed for aneurysm treatment. Methods We identified five patients who were treated with the Pipeline embolization device (PED) in conjunction with a Neuroform EZ stent for inadequate wall apposition of the ends of the FD at our institution between May 2014 and July 2015. Among other parameters, angiographic results, cone-beam computed tomography assessment of wall apposition and patient clinical outcome were evaluated. Results Incomplete device end apposition was seen in three cases, and precarious positioning of the distal end of the PED over the aneurysm neck was seen in two cases. In all five cases, successful treatment with good wall apposition and proper pinning of the PED distal edge was achieved using an additional Neuroform EZ stent. Appropriate aneurysm neck coverage and flow stagnation was seen in all cases. The combination of high radial outward force and open-cell design permits the Neuroform EZ stent to jail the malappositioned edges of the FD while maintaining good vessel-wall apposition itself and prevent migration of the PED. Short-term follow-up angiography showed device patency and complete aneurysm obliteration in all cases. Conclusions Preliminary results of this small case series suggest that the Neuroform EZ stent allows for effective treatment of FD malapposition in selected patients amenable for this endovascular approach. Long-term and larger cohort studies are needed to validate these results.

Use of the Pipeline embolization device for recurrent and residual cerebral aneurysms: a safety and efficacy analysis with short-term follow-up.

OBJECTIVE: Evaluation of the safety and efficacy of the Pipeline embolization device (PED) when used as second-line treatment for recurrent or residual, pretreated ruptured and unruptured intracranial aneurysms (IAs). METHODS: Retrospective review of our database to include all patients who were treated with a PED for recurrent or residual IAs following surgical clipping or coiling. We evaluated neurological outcome and angiograms at discharge, 6- and 12-months' follow-up and assessed intimal hyperplasia at follow-up. RESULTS: Twenty-four patients met our inclusion criteria. Most IAs were located in the anterior circulation (n=21). No change of preprocedure modified Rankin Scale score was seen at discharge or at any scheduled follow-up. Complete or near-complete aneurysm occlusion on 6- and 12-month angiograms was seen in 94.4% (17/18 cases) and 93.3% (14/15 cases), respectively. Complete or near-complete occlusion was seen in 100% of previously ruptured and 85.7% (6/7 cases) and 83.3% (5/6 cases) of previously unruptured cases at the 6- and 12-months' follow-up, respectively. One case of moderate intimal hyperplasia was observed at 6 months and decreased to mild at the 12-months' follow-up. No difference in device performance was observed among pretreated unruptured or ruptured IAs. CONCLUSIONS: Treatment of recurrent or residual IAs with a PED after previous coiling or clipping is feasible and safe. There is no difference in device performance between ruptured or unruptured IAs.

Trigeminocardiac reflex caused by selective angiography of the middle meningeal artery.

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted.

Trigeminocardiac reflex caused by selective angiography of the middle meningeal artery.

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted.

Utilization of a New Intracranial Support Catheter as an Intermediate Aspiration Catheter in the Treatment of Acute Ischemic Stroke: Technical Report on Initial Experience.

The endovascular management of acute ischemic stroke (AIS) due to emergency large vessel occlusion (ELVO) has become the standard of care after the recent publication of landmark randomized, controlled trials. Mechanical thrombectomy, in addition to intravenous thrombolysis (within 4.5 hours when eligible), is now part of the algorithm of the standard of care when treating AIS in patients with ELVO in the anterior circulation up to six hours after symptom onset. A newly introduced device, the Arc™ intracranial support catheter (Medtronic, Irvine, USA), is specifically designed for the introduction of neurointerventional devices into the cerebral vasculature and facilitates the delivery of microcatheters into smaller, more distal intracranial vessels. This technical report describes the use of the Arc™ intracranial support catheter in the setting of AIS.

Lobar distribution of lesion volumes in late-life depression: the Biomedical Informatics Research Network (BIRN).

White matter hyperintense lesions on T2-weighted images are associated with late-life depression. Little work has been carried out examining differences in lesion location between elderly individuals with and without depression. In contrast to previous studies examining total brain white matter lesion volume, this study examined lobar differences in white matter lesion volumes derived from brain magnetic resonance imaging. This study examined 49 subjects with a DSM-IV diagnosis of major depression and 50 comparison subjects without depression. All participants were age 60 years or older. White matter lesion volumes were measured in each hemisphere using a semiautomated segmentation process and localized to lobar regions using a lobar atlas created for this sample using the imaging tools provided by the Biomedical Informatics Research Network (BIRN). The lobar lesion volumes were compared against depression status. After controlling for age and hypertension, subjects with depression exhibited significantly greater total white matter lesion volume in both hemispheres and in both frontal lobes than did control subjects. Although a similar trend was observed in the parietal lobes, the difference did not reach a level of statistical significance. Models of the temporal and occipital lobes were not statistically significant. Older individuals with depression have greater white matter disease than healthy controls, predominantly in the frontal lobes. These changes are thought to disrupt neural circuits involved in mood regulation, thus increasing the risk of developing depression.

Quantitative evaluation of automated skull-stripping methods applied to contemporary and legacy images: effects of diagnosis, bias correction, and slice location.

Performance of automated methods to isolate brain from nonbrain tissues in magnetic resonance (MR) structural images may be influenced by MR signal inhomogeneities, type of MR image set, regional anatomy, and age and diagnosis of subjects studied. The present study compared the performance of four methods: Brain Extraction Tool (BET; Smith [2002]: Hum Brain Mapp 17:143-155); 3dIntracranial (Ward [1999] Milwaukee: Biophysics Research Institute, Medical College of Wisconsin; in AFNI); a Hybrid Watershed algorithm (HWA, Segonne et al. [2004] Neuroimage 22:1060-1075; in FreeSurfer); and Brain Surface Extractor (BSE, Sandor and Leahy [1997] IEEE Trans Med Imag 16:41-54; Shattuck et al. [2001] Neuroimage 13:856-876) to manually stripped images. The methods were applied to uncorrected and bias-corrected datasets; Legacy and Contemporary T1-weighted image sets; and four diagnostic groups (depressed, Alzheimer's, young and elderly control). To provide a criterion for outcome assessment, two experts manually stripped six sagittal sections for each dataset in locations where brain and nonbrain tissue are difficult to distinguish. Methods were compared on Jaccard similarity coefficients, Hausdorff distances, and an Expectation-Maximization algorithm. Methods tended to perform better on contemporary datasets; bias correction did not significantly improve method performance. Mesial sections were most difficult for all methods. Although AD image sets were most difficult to strip, HWA and BSE were more robust across diagnostic groups compared with 3dIntracranial and BET. With respect to specificity, BSE tended to perform best across all groups, whereas HWA was more sensitive than other methods. The results of this study may direct users towards a method appropriate to their T1-weighted datasets and improve the efficiency of processing for large, multisite neuroimaging studies.

Mapping cortical thickness and gray matter concentration in first episode schizophrenia.

We mapped regional changes in cortical thickness and intensity-based cortical gray matter concentration in first episode schizophrenia. High-resolution magnetic resonance images were obtained from 72 (51 male, 21 female) first episode patients and 78 (37 male, 41 female) healthy subjects similar in age. Cortical pattern matching methods allowed comparisons of cortical thickness and gray matter concentration at thousands of homologous cortical locations between subjects in three dimensions. Principal components analyses reduced measures obtained across the cortex to identify global differences in cortical thickness/gray matter concentration. First principal component factor scores showed significant effects of diagnosis, sex and age for both cortical measures. Diagnosis and age effects remained significant after brain size correction. Cortical thickness and gray matter concentration values were highly correlated. Statistical maps showed significant regional gray matter thinning in frontal, temporal and parietal heteromodal association cortices bilaterally in first episode patients. Regional reductions in cortical gray matter concentration were similar but pronounced in the superior temporal lobe. Regional reductions in cortical thickness and gray matter concentration are present at disease onset in brain regions linked with functional disturbances in schizophrenia. Cortical thickness and gray matter concentration mapping produce similar results, although the concentration metric may be influenced by diagnostic differences in extra-cortical cerebrospinal fluid and surface curvature/complexity.

A meta-algorithm for brain extraction in MRI.

Accurate identification of brain tissue and cerebrospinal fluid (CSF) in a whole-head MRI is a critical first step in many neuroimaging studies. Automating this procedure can eliminate intra- and interrater variance and greatly increase throughput for a labor-intensive step. Many available procedures perform differently across anatomy and under different acquisition protocols. We developed the Brain Extraction Meta-Algorithm (BEMA) to address these concerns. It executes many extraction algorithms and a registration procedure in parallel to combine the results in an intelligent fashion and obtain improved results over any of the individual algorithms. Using an atlas space, BEMA performs a voxelwise analysis of training data to determine the optimal Boolean combination of extraction algorithms to produce the most accurate result for a given voxel. This allows the provided extractors to be used differentially across anatomy, increasing both the accuracy and robustness of the procedure. We tested BEMA using modified forms of BrainSuite's Brain Surface Extractor (BSE), FSL's Brain Extraction Tool (BET), AFNI's 3dIntracranial, and FreeSurfer's MRI Watershed as well as FSL's FLIRT for the registration procedure. Training was performed on T1-weighted scans of 136 subjects from five separate data sets with different acquisition parameters on separate scanners. Testing was performed on 135 separate subjects from the same data sets. BEMA outperformed the individual algorithms, as well as interrater results from a subset of the scans, when compared for the mean Dice coefficient, a rating of the similarity of output masks to the manually defined gold standards.

Gender differences in cortical complexity.

Cortical complexity, a measure that quantifies the spatial frequency of gyrification and fissuration of the brain surface, has not been thoroughly characterized with respect to gender differences in the human brain. Using a new three-dimensional (3D) analytic technique with magnetic resonance imaging, we found greater gyrification in women than men in frontal and parietal regions. Increased complexity implies more cortical surface area, which may offset gender differences in brain volume and account for behavioral gender differences.

Comparing gray matter loss profiles between dementia with Lewy bodies and Alzheimer's disease using cortical pattern matching: diagnosis and gender effects.

We used magnetic resonance imaging (MRI) and cortical pattern matching to map differences in cortical gray matter deficits between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB), and explored the possible influence of gender on these patterns. Twenty-nine patients with AD (age 77.9 +/- 5.5), 16 patients with DLB (76.4 +/- 6.7), and 38 controls (75.3 +/- 6.8) were included. Dementia groups were matched for illness severity. Detailed spatial analyses of gray matter were conducted across the entire cerebral cortex by measuring local proportions of gray matter at thousands of homologous cortical surface locations in each subject and between diagnostic groups. To visualize regional changes, statistical differences were mapped at each cortical surface location in 3D. Main effects of diagnosis demonstrated prominent gray matter differences in orbitofrontal and temporal cortices, where AD exhibited the greatest deficits relative to DLB. Main effects of sex showed less gray matter in men within all group comparisons. Exploratory findings for sex by diagnosis interactions suggest greater gray matter loss in the anterior cingulate for men with AD, relative to controls, AD females, and individuals with DLB. Relative preservation of orbitofrontal cortices in addition to temporal structures may contribute to distinguishing DLB from AD. Further investigation of the influence of gender might provide a more comprehensive understanding of the pathophysiological differences underlying the two forms of dementia.

The LONI Pipeline Processing Environment.

The analysis of raw data in neuroimaging has become a computationally entrenched process with many intricate steps run on increasingly larger datasets. Many software packages exist that provide either complete analyses or specific steps in an analysis. These packages often possess diverse input and output requirements, utilize different file formats, run in particular environments, and have limited abilities with certain types of data. The combination of these packages to achieve more sensitive and accurate results has become a common tactic in brain mapping studies but requires much work to ensure valid interoperation between programs. The handling, organization, and storage of intermediate data can prove difficult as well. The LONI Pipeline Processing Environment is a simple, efficient, and distributed computing solution to these problems enabling software inclusion from different laboratories in different environments. It is used here to derive a T1-weighted MRI atlas of the human brain from 452 normal young adult subjects with fully automated processing. The LONI Pipeline Processing Environment's parallel processing efficiency using an integrated client/server dataflow model was 80.9% when running the atlas generation pipeline from a PC client (Acer TravelMate 340T) on 48 dedicated server processors (Silicon Graphics Inc. Origin 3000). The environment was 97.5% efficient when the same analysis was run on eight dedicated processors.

Multiwavelength optical intrinsic signal imaging of cortical spreading depression.

Cortical spreading depression (CSD) is an important disease model for migraine and cerebral ischemia. In this study, we exploit the high temporal and spatial resolution of optical imaging to characterize perfusion-dependent and -independent changes in response to CSD and to investigate the etiology of reflectance changes during CSD. In this experiment, we characterized the optical response to CSD at wavelengths that emphasize perfusion-related changes (610 and 550 nm), and we compared these results with 850 nm and blood volume data. Blood volume changes during CSD were recorded using an intravascular fluorescent dye, Texas Red dextran. We observed triphasic optical signals at 850 and 550 nm characterized by spreading waves of increased, decreased, then increased reflectance (Fig. 1) which expanded at a rate of approximately 3-5 mm/min. The signal at 610 nm had a similar initial phase, but the phase 2 response was slightly more complex, with a parenchymal decrease in reflectance but a vascular increase in reflectance. Reflectance values decreased in phase three. Blood volume signals were delayed relative to the optical intrinsic signals and corresponded temporally to phases 2 and 3. This is the first study to characterize optical imaging of intrinsic signal responses to CSD, in vivo, at multiple wavelengths. The data presented here suggest that changes in light scattering precede perfusion responses, the blood volume increase (phase 2) is accompanied by a reduction in deoxyhemoglobin, and the blood volume decrease (phase 3) is accompanied by an increase in deoxyhemoglobin. Previous studies have suggested the oligemia of spreading depression was a result of decreased metabolic demand. This study suggests that during the oligemic period there is a greater reduction in oxygen delivery than in demand.

Utility of preoperative functional magnetic resonance imaging for identifying language cortices in patients with vascular malformations.

OBJECT: The goal of this study was to evaluate the utility of preoperative functional magnetic resonance (fMR) imaging in the prediction of whether a given cortical area would be deemed essential for language processing by electrocortical stimulation mapping (ESM). METHODS: The authors studied patients with vascular malformations, specifically arteriovenous malformations (AVMs) and cavernous angiomas, in whom blood-flow patterns are not normal and in whom a perfusion-dependent mapping signal may be questionable. Ten patients were studied (seven harboring AVMs and three with cavernous angiomas). The authors used a battery of linguistic tasks, including visual object naming, word generation, auditory responsive naming, visual responsive naming, and sentence comprehension, to identify brain regions that were consistently activated across expression and comprehension linguistic tasks. In a comparison of ESM and fMR imaging activations, the authors varied the matching criteria (overlapping activations, adjacent activations, and deep activations) and the radii of influence of ESM (2.5, 5, and 10 mm) to determine the effects of these factors on the sensitivity and specificity of fMR imaging. The sensitivity and specificity of fMR imaging were dependent on the task, lobe, and matching criterion. For the population studied, the sensitivity and specificity of fMR imaging activations during expressive linguistic tasks were found to be up to 100 and 66.7%, respectively, in the frontal lobe, and during comprehension linguistic tasks up to 96.2 and 69.8%, respectively, in the temporal and parietal lobes. The sensitivity and specificity of each disease population (patients with AVMs and those with cavernous angiomas) and of individuals were consistent with those values reported for the entire population studied. CONCLUSIONS: The authors conclude that preoperative fMR imaging is a highly sensitive preoperative planning tool for the identification of which cortical areas are essential for language and that this imaging modality may play a future role in presurgical planning for patients with vascular malformations.

Utility of preoperative functional magnetic resonance imaging for identifying language cortices in patients with vascular malformations.

OBJECT: The goal of this study was to evaluate the utility of preoperative functional magnetic resonance (fMR) imaging in the prediction of whether a given cortical area would be deemed essential for language processing by electrocortical stimulation mapping (ESM). METHODS: The authors studied patients with vascular malformations, specifically arteriovenous malformations (AVMs) and cavernous angiomas, in whom blood-flow patterns are not normal and in whom a perfusion-dependent mapping signal may be questionable. Ten patients were studied (seven harboring AVMs and three with cavernous angiomas). The authors used a battery of linguistic tasks, including visual object naming, word generation, auditory responsive naming, visual responsive naming, and sentence comprehension, to identify brain regions that were consistently activated across expression and comprehension linguistic tasks. In a comparison of ESM and fMR imaging activations, the authors varied the matching criteria (overlapping activations, adjacent activations, and deep activations) and the radii of influence of ESM (2.5, 5, and 10 mm) to determine the effects of these factors on the sensitivity and specificity of fMR imaging. The sensitivity and specificity of fMR imaging were dependent on the task, lobe, and matching criterion. For the population studied, the sensitivity and specificity of fMR imaging activations during expressive linguistic tasks were found to be up to 100 and 66.7%, respectively, in the frontal lobe, and during comprehension linguistic tasks up to 96.2 and 69.8%, respectively, in the temporal and parietal lobes. The sensitivity and specificity of each disease population (patients with AVMs and those with cavernous angiomas) and of individuals were consistent with those values reported for the entire population studied. CONCLUSIONS: The authors conclude that preoperative fMR imaging is a highly sensitive preoperative planning tool for the identification of which cortical areas are essential for language and that this imaging modality may play a future role in presurgical planning for patients with vascular malformations.