Refinement of nBCA embolization technique in treatment of metastatic spinal tumors: Case series and technical report.

BACKGROUND AND OBJECTIVES: Preoperative embolization of metastatic spinal tumors (MSTs) has proven advantageous in limiting intraoperative blood loss (IBL) during resection. N-butyl cyanoacrylate (nBCA) is a liquid embolic agent known for its rapid hemostatic effects. However, nBCA is associated with a higher risk of distal nontarget embolization. This study highlights the refinement of the embolization technique and assesses its efficacy in performing an initial distal segmental artery plug with concentrated nBCA followed by proximal diluted nBCA for MSTs. METHODS: A retrospective review of patients with MST (2018-2023) was performed. Patients who underwent preoperative nBCA endovascular embolization prior to tumor resection and spinal instrumentation were included. Baseline standard spinal angiography was performed. RESULTS: Sixteen patients (13 men, 3 women; 56.0 ± 12.4 years) met inclusion criteria. And 43.75% (7 of 16) had thoracic levels, 37.5% (6 of 16) lumbar, and 18.75% (3 of 16) sacral. The most common primary tumor was renal cell carcinoma (43.75%, 7 of 16). A total of 43 pedicles were embolized (median 3), resulting in complete/near complete obliteration of the tumor blush. Most pedicles (83.7%, 36 of 43) received a single dilute concentration of nBCA; however, 16.3% (7 of 43) received two separate concentrations of nBCA, a denser concentration distally into the segmental artery and a diluted concentration proximally into the tumor bed. Mean IBL was 1150 ± 1201 mL in 3 distal plug patients distal plug patients versus 1625 ± 681 mL in 12 other patients. There were no complications related to embolization. CONCLUSION: Performing a distal, concentrated nBCA plug during preoperative nBCA embolization of MSTs may increase tumor penetration and reduce IBL.

Are hemodynamics responsible for inflammatory changes in venous vessel walls? A quantitative study of wall-enhancing intracranial arteriovenous malformation draining veins.

OBJECTIVE: Signal enhancement of vascular walls on vessel wall MRI might be a biomarker for inflammation. It has been theorized that contrast enhancement on vessel wall imaging (VWI) in draining veins of intracranial arteriovenous malformations (AVMs) may be associated with disease progression and development of venous stenosis. The aim of this study was to investigate the relationship between vessel wall enhancement and hemodynamic stressors along AVM draining veins. METHODS: Eight AVM patients with 15 draining veins visualized on VWI were included. Based on MR venography data, patient-specific 3D surface models of the venous anatomy distal to the nidus were segmented. The enhanced vascular wall regions were manually extracted and mapped onto the venous surface models after registration of image data. Using image-based blood flow simulations applying patient-specific boundary conditions based on phase-contrast quantitative MR angiography, hemodynamics were investigated in the enhanced vasculature. For the shear-related parameters, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), and relative residence time (RRT) were calculated. Velocity, oscillatory velocity index (OVI), and vorticity were extracted for the intraluminal flow-related hemodynamics. RESULTS: Visual observations demonstrated overlap of enhancement with local lower shear stresses resulting from decreased velocities. Thus, higher RRT values were measured in the enhanced areas. Furthermore, nonenhancing draining veins showed on average slightly higher flow velocities and TAWSS. Significant decreases of 55% (p = 0.03) for TAWSS and of 24% (p = 0.03) for vorticity were identified in enhanced areas compared with near distal and proximal domains. Velocity magnitude in the enhanced region showed a nonsignificant decrease of 14% (p = 0.06). Furthermore, increases were present in the OSI (32%, p = 0.3), RRT (25%, p = 0.15), and OVI (26%, p = 0.3) in enhanced vessel sections, although the differences were not significant. CONCLUSIONS: This novel multimodal investigation of hemodynamics in AVM draining veins allows for precise prediction of occurring shear- and flow-related phenomena in enhanced vessel walls. These findings may suggest low shear to be a local predisposing factor for venous stenosis in AVMs.

The natural history of aneurysms incompletely occluded by placement of a flow diverter: a multiinstitutional study.

OBJECTIVE: Treatment of intracranial aneurysms by flow diversion is safe and effective and is increasingly popular. However, the correct treatment paradigm for aneurysms incompletely treated by initial placement of a flow diverter has not been established, nor have the subsequent natural history and occlusion rates of such aneurysms. The authors sought to outline the natural history of such aneurysms, which to date have been considered partially treated. METHODS: The authors retrospectively reviewed consecutive cases from 6 high-volume neurointerventional services, including all cases in which the first follow-up imaging after placement of a flow diverter showed incomplete occlusion of the aneurysm, and for which subsequent clinical and/or radiological follow-up was available. All included patients were treated with the Pipeline Flex embolization device or the Pipeline Flex embolization device with Shield Technology. Subsequent radiographic and clinical outcome data were collected and analyzed using the Kaplan-Meier survival function. RESULTS: A total of 263 patients with persistently patent aneurysms on first follow-up imaging after flow diversion were identified. Of these, 204 had clinical follow-up and 152 had additional imaging follow-up. Of this final cohort, 148 aneurysms were unruptured, and 4 were ruptured. The average aneurysm size by maximum dimension was 10.8 mm. The average recorded follow-up was 27.8 months in the cohort, with some patients followed for as long as 9 years from treatment. Over the course of 403 person-years of follow-up, no delayed aneurysm ruptures were recorded. Both with and without retreatment, aneurysms showed a trend toward progressive occlusion over time. Complications related to device placement were low. CONCLUSIONS: Aneurysms that have been incompletely treated by flow diversion have a benign natural history with progression toward occlusion over time, with or without retreatment.

Predictors of angiographic resolution in patients with presumed reversible cerebral vasoconstriction syndrome.

INTRODUCTION: Reversible cerebral vasoconstriction syndrome is a complex neurovascular syndrome that presents with varying neurological deficits as well as segmental vasoconstriction of the small and medium cerebral arteries. There is limited literature on pathologies that mimic reversible cerebral vasoconstriction syndrome, so this study aims to understand what factors may impact the angiographic confirmation of reversible cerebral vasoconstriction syndrome on follow-up and play a role in establishing the diagnosis. METHODS: The Clinical Research Data Warehouse at this institution was employed to search the medical records for patients with diagnosis and treatment of reversible cerebral vasoconstriction syndrome between January 2010 and May 2021. After screening, 32 patients met the inclusion criteria for a presumed diagnosis of reversible cerebral vasoconstriction syndrome with both angiography on presentation and at three-month follow-up after treatment. Patients were divided into two categories: those with complete angiographic resolution, versus partial or no improvement on follow-up. Clinical and radiographic data were analyzed. RESULTS: Patients who had partial or no resolution were more likely to have a history of hypertension (p = 0.001), higher systolic blood pressure on admission (p = 0.047), and present with a recurrent thunderclap headache (p = 0.038). Binary logistic regression selected for hypertension (odds ratio [OR] 18.35 [95% CI, 1.37-245.1]) as predictive of not having reversible cerebral vasoconstriction syndrome, as can be seen by partial or no resolution on follow-up angiography (p = 0.028). CONCLUSION: Complete resolution on follow-up angiography is a distinguishing factor of reversible cerebral vasoconstriction syndrome. Our analysis revealed that a history of hypertension is the most significant predictor of confirming that a patient may not have reversible cerebral vasoconstriction syndrome. This is due, in part, to increased atherosclerotic or hypertensive cerebral arterial changes, which can mimic reversible cerebral vasoconstriction syndrome and present as partial or no resolution on angiography.

The correlation of cerebral arteriovenous malformation flow measured by quantitative MR angiography on MR-detected arteriovenous malformation microhemorrhage.

OBJECTIVE: The objective of this study was to assess the relationship of arteriovenous malformation (AVM) blood flow measured by quantitative MR angiography (QMRA) in nonruptured AVMs with MR-detected microhemorrhage. METHODS: All patients with unruptured AVMs who received baseline QMRA and gradient echo or susceptibility-weighted MRI were retrospectively reviewed (2004-2022). Imaging data, clinical history, and AVM angioarchitectural and flow features were collected and assessed. AVM flow was calculated from the difference of flow within primary arterial feeders from their contralateral counterparts. A review of the MR images determined the presence of microhemorrhages. Analysis of descriptive statistics, chi-square test, and binomial logistic regression were performed. RESULTS: Of 634 patients with cerebral AVMs at a single center, 89 patients met the inclusion criteria (54 with microhemorrhage and 35 without microhemorrhage). The calculated AVM flow was significantly higher in the group with a microhemorrhage (447.9 ± 193.1 ml/min vs 287.6 ± 235.7 ml/min, p = 0.009). In addition, the presence of venous anomaly, arterial ectasia, and diffuse nidus was significantly associated with microhemorrhage (p = 0.017, p = 0.041, and p = 0.041, respectively). Binary logistic regression found that higher flow predicted the presence of microhemorrhage (OR 1.002, 95% CI 1.000-1.004; p = 0.031). The highest AVM flow quartile significantly predicted the presence of venous anomaly (OR 3.840, 95% CI 1.037-14.213; p = 0.044), diffuse nidus (OR 6.800, 95% CI 1.766-25.181; p = 0.005), and arterial ectasia (OR 13.846, 95% CI 1.905-122.584; p = 0.018). CONCLUSIONS: This study represents the first to examine the association between flow measurements on QMRA with microhemorrhage in unruptured AVMs. Higher AVM flow, venous anomaly, arterial ectasia, and diffuse AVM nidus were related to a higher likelihood of AVM microhemorrhage. Higher AVM flow was present in AVMs with venous anomalies, a diffuse nidus, and arterial ectasia, indicating a possible interaction between these angioarchitectural findings, AVM flow, and microhemorrhage. These findings suggest a relationship between higher AVM flow and the risk of microhemorrhage.

Spiral laser scanning photoacoustic microscopy for functional brain imaging in rats.

Significance: There are many neuroscience questions that can be answered by a high-resolution functional brain imaging system. Such a system would require the capability to visualize vasculature and measure neural activity by imaging the entire brain continually and in rapid succession in order to capture hemodynamic changes. Utilizing optical excitation and acoustic detection, photoacoustic technology enables label-free quantification of changes in endogenous chromophores, such as oxyhemoglobin, deoxyhemoglobin, and total hemoglobin. Aim: Our aim was to develop a sufficiently high-resolution, fast frame-rate, and wide field-of-view (FOV) photoacoustic microscopy (PAM) system for the purpose of imaging vasculature and hemodynamics in a rat brain. Approach: Although the most PA microscopy systems use raster scanning (or less commonly Lissajous scanning), we have developed a simple-to-implement laser scanning optical resolution PAM system with spiral scanning (which we have named "spiral laser scanning photoacoustic microscopy" or sLS-PAM) to acquire an 18 mm diameter image at fast frame rate (more than 1 fps). Such a system is designed to permit continuous rat brain imaging without the introduction of photobleaching artifacts. Conclusion: We demonstrated the functional imaging capability of the sLS-PAM system by imaging cerebral hemodynamics in response to whisker and electrical stimulation and used it for vascular imaging of a modeled brain injury. We believe that we have demonstrated the development of a simple-to-implement PAM system, which could become an affordable functional neuroimaging tool for researchers.

Evaluating outcome associations with race after mechanical thrombectomy: an analysis of the NVQI-QOD acute ischemic stroke registry.

BACKGROUND: Mechanical thrombectomy has become the standard of care for acute ischemic stroke due to large vessel occlusions. Racial differences in outcomes after mechanical thrombectomy for acute ischemic stroke have not been extensively studied. We evaluate the real-world evidence for differences between races in the outcomes of thrombectomy for large vessel occlusions using the NeuroVascular Quality Initiative-Quality Outcomes Database (NVQI-QOD). METHODS: Data from the NVQI-QOD acute ischemic stroke registry were analyzed and compared for racial differences in outcomes after mechanical thrombectomy in 4507 patients from 28 US centers (17 states) between January 2014 and April 2021. Race was dichotomized into non-Hispanic White (NHW, n=3649) and non-Hispanic Black (NHB, n=858). We performed 1:1 propensity score matching resulting in a subsample of matched groups (n=761 each for NHB and NHW) to compare study endpoints using Welch's two-sided t-tests and Χ2 test for continuous and categorical outcomes, respectively. RESULTS: Prior to matching, NHW and NHB patients significantly differed in age, comorbidities, medication use, smoking status, and presenting stroke severity. No significant difference in functional outcomes or mortality, at discharge or follow-up, were revealed. NHB patients had higher average postprocedure length of stay than NHW patients, which persisted following matching (11.2 vs 9.1 days, P=0.004). CONCLUSION: Evidence from the NVQI-QOD acute ischemic stroke registry showed that outcome metrics, such as modified Rankin Scale score and mortality, did not differ significantly between racial groups; however, disparity between NHW and NHB patients in postprocedure length of stay following mechanical thrombectomy was revealed.

Assessing the efficacy of VerifyNow platelet-function testing in predicting postoperative hemorrhagic complications of neuroendovascular surgery: A systematic review and meta-analysis (part 2).

BACKGROUND: Dual antiplatelet therapy is used to reduce the risk of thromboembolic complications in neuroendovascular surgery. However, the predictive utility of preoperative platelet-sensitivity testing for decreasing bleed risk in patients undergoing endovascular neurointervention remains unclear. OBJECTIVE: We conducted a systematic review and meta-analysis to illustrate the association between platelet response and risk of hemorrhagic complications from neuroendovascular surgery, examine the efficacy of the VerifyNow platelet reactivity unit (PRU) assay in predicting hemorrhagic outcomes, and assess whether a clinically useful threshold for platelet response can be defined to standardize guidelines. METHODS: PubMed, Embase, and Scopus were searched. Articles were screened for relevance by title and abstract, followed by full text. RESULTS: Of 735 resultant articles, 17 studies of 2084 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 37.8% were treated with flow diversion, 22.4% with stent-assisted coil embolization, 14.3% with intracranial stenting, 12.8% with simple coil embolization, 5.8% with balloon-assisted coil embolization, 2.0% with extracranial stenting, and 4.8% with an alternate method. Precisely, 52.9% (9 out of 17) of studies determined platelet hyperresponse to be an independent predictor of postoperative hemorrhagic complications, with 11.8% (2 out of 17) of studies reporting a similar but non-statistically significant trend. 35.3% (6 out of 17) of studies found no relationship between platelet response and postoperative hemorrhagic complications. The estimated clinical threshold for PRU to prevent hemorrhagic complications varied considerably across studies (range: <46-118 PRU). Meta-analysis found platelet hyperresponse to have more than a 3-fold increased risk of hemorrhagic complications compared to normoresponders (relative risk = 3.2, p = 0.001). CONCLUSION: Although this meta-analysis shows the predictive utility of the P2Y12 assay for postoperative hemorrhagic complications in neuroendovascular surgery, the optimal therapeutic threshold for minimizing bleeding risk is still uncertain. To better understand the utility of the P2Y12 assay in the perioperative period, further prospective research is needed.

Assessing the efficacy of VerifyNow platelet-function testing in predicting postoperative thromboembolic complications of neuroendovascular surgery: A systematic review and meta-analysis (part 1).

BACKGROUND: Despite the heavily debated use of routine platelet-function testing, the VerifyNow Platelet Reactivity Unit (PRU) assay has been increasingly adopted as standard of care for assessing risk of postoperative thromboembolic complications of neuroendovascular surgery. OBJECTIVE: We conducted a systematic review and meta-analysis to examine the relationship between platelet response and risk of ischemic events from neuroendovascular surgery, assess the efficacy of point-of-care platelet-function testing in predicting thromboembolic outcomes, and assess whether a clinically useful threshold for platelet response can be defined in order to standardize guidelines. METHODS: PubMed, Embase, and Scopus were searched. Following deduplication, articles were first screened for relevance by title and abstract, followed by full text. RESULTS: Of 735 resultant articles, 22 studies consisting of 3266 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 45.8% were treated with flow diversion, 16.4% with stent-assisted coil embolization, 15.8% with intracranial stenting, 12.0% with simple coil embolization, 3.4% with balloon-assisted coil embolization, 3.6% with extracranial stenting, and 3.0% with an alternate method. 54.5% (12/22) of studies determined platelet hyporesponse to be an independent predictor of postoperative thromboembolic complications, with 27.3% (6/22) of studies reporting a similar, but non-statistically significant trend. 18.2% (4/22) of studies found no relationship between platelet response and postoperative thromboembolic complications. The estimated clinical threshold for PRU to prevent thromboembolic complications varied greatly across studies (Range: > 144-295 PRU). Meta-analysis found platelet hyporesponse to have a 2.23-fold increased risk of thromboembolic complications compared to normoresponders (RR = 2.23, P = 0.03). CONCLUSION: While PRU demonstrates a significant predictive value for postoperative thromboembolic complications of neuroendovascular surgery, the target therapeutic threshold for minimizing ischemic events remains unclear. Further studies, such as large multicenter cohorts of the existing data, are needed to standardize guidelines.

WITHDRAWN: A narrative review of techniques for surgical revascularization of the extracranial vertebral artery in vertebrobasilar insufficiency.

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Neurochirurgie, volume 70. https://doi.org/10.1016/j.neuchi.2023.101516. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

5-year stroke rates in nonvalvular atrial fibrillation after watchman compared to direct oral anticoagulants.

BACKGROUND: The WATCHMAN device (Boston Scientific; Marlborough, MA, USA) is noninferior to warfarin in preventing ischemic strokes while reducing bleeding risks associated with long term anticoagulation in nonvalvular atrial fibrillation (AFib). The device's performance compared to direct oral anticoagulants (DOAC) is less well known. OBJECTIVE: To compare 5-year major bleeding and ischemic stroke rates in patients with nonvalvular AFib who received a WATCHMAN device or DOAC therapy after a major bleeding event. METHODS: This retrospective, multicenter, 1:1 matched cohort study was derived from the PearlDiver Mariner database from 2010 to 2020. Patients with nonvalvular AFib on oral anticoagulation who had a major bleeding event were identified. Those who received either WATCHMAN or DOAC after resolution of the bleeding event were selected. The two groups were exactly matched 1:1 based on various comorbidities. Rates of ischemic stroke, transient ischemic attack (TIA), major bleeding, and hemorrhagic stroke were compared over 5 years. RESULTS: Each cohort consisted of 2248 patients after 1:1 matching. The mean CHADS2-VASC score was 4.81 ±â€¯1.25. At 5 years, the WATCHMAN cohort had significantly lower rates of major bleeding events [OR 0.24 (0.21, 0.27)], TIAs [OR 0.75 (0.58, 0.95)], and ischemic strokes [OR 0.72 (0.61, 0.86)]. There was no significant difference in hemorrhagic strokes [OR 1.14 (0.83, 1.58)]. CONCLUSION: Even in a high-risk population, the WATCHMAN is comparable to DOAC therapy in the primary prevention of hemorrhagic strokes and may provide benefit in the rates of bleeding events, TIAs, and ischemic strokes.

A narrative review of techniques for surgical revascularization of the extracranial vertebral artery in vertebrobasilar insufficiency.

Vertebrobasilar insufficiency is a condition characterized by poor blood flow through the posterior circulation of the brain, which supplies the brainstem, thalamus, hippocampus, cerebellum, occipital lobes, and medial temporal lobes. Narrowing or occlusion of the vertebral arteries may be result in a range of neurological symptoms, including dizziness, imbalance, dysarthria, and even stroke. If symptomatic patients fail medical management, revascularization of the vertebral artery should be considered. Restoration of blood flow may involve transluminal balloon angioplasty or stent placement; however, certain cases may still require surgical intervention. The complexity of surgical revascularization of the vertebral artery requires careful consideration of skull base and neck anatomy. This review article will focus on bypass of the vertebral artery in the setting of ischemic pathology, describing the technique, anatomical nuances, steps involved in preoperative planning, and postoperative management.

Rupture-Risk Stratifying Patients with Cerebral Arteriovenous Malformations Using Quantitative Hemodynamic Flow Measurements.

Arteriovenous malformations (AVMs) are high-pressure, low-resistance arterial-venous shunts without intervening capillaries. Up to 60% of AVMs present with an intracranial hemorrhage; however, noninvasive neuroimaging has increasingly diagnosed incidental AVMs. AVM management depends on weighing the lifetime rupture risk against the risks of intervention. Although AVM rupture risk relies primarily on angioarchitectural features, measuring hemodynamic flow is gaining traction. Accurate understanding of AVM hemodynamic flow parameters will help endovascular neurosurgeons and interventional neuroradiologists stratify patients by rupture risk and select treatment plans. This review examines various neuroimaging modalities and their capabilities to quantify AVM flow, as well as the relationship between AVM flow and rupture risk. Quantitative hemodynamic studies on the relationship between AVM flow and rupture risk have not reached a clear consensus; however, the preponderance of data suggests that higher arterial inflow and lower venous outflow in the AVM nidus contribute to increased hemorrhagic risk. Future studies should consider using larger sample sizes and standardized definitions of hemodynamic parameters to reach a consensus. In the meantime, classic angioarchitectural features may be more strongly correlated with AVM rupture than the amount of blood flow.

Lipidomics, Acute Ischemic Stroke, Symptoms, and Outcomes: Observational Study Protocol.

BACKGROUND: Acute ischemic stroke is one of the leading causes of death and disability globally. Recent advances in omics methodology enable lipidomic profiling, which may provide knowledge of the underlying pathology of acute ischemic stroke and its associated outcomes. OBJECTIVE: This study aims to examine the longer-term relationships between symptoms and outcomes following acute ischemic stroke and the underlying lipidomic signatures over 6 months during recovery between acute ischemic stroke patients who received reperfusion therapies and those who did not. METHODS: This prospective cohort study will enroll 104 participants post-acute ischemic stroke in two groups based on their receipt of reperfusion therapy (Group 1) or not (Group 2; n = 52/group). Peripheral plasma samples will be collected from both groups for lipidomic analysis over 6 months. Arterial blood samples will be collected during the procedure for those receiving reperfusion. Self-reported symptoms and outcome data will be collected from both groups. DISCUSSION: We will compare and examine the associations among plasma lipidomic biomarkers and symptoms and cognitive, functional, and health-related quality of life outcomes over 6 months between acute ischemic stroke patients who did and did not receive reperfusion intervention.

Ruptured isolated spinal artery aneurysms: Case series of five patients and a review of the literature on management strategies.

BACKGROUND: Aneurysms of the spinal arteries are rare entities, the majority of which are associated with other vascular lesions, such as spinal vascular malformations. Isolated spinal artery aneurysms (SAAs) are even less frequently encountered, and their incidence is largely unknown, as the literature is limited to case reports and small series. The optimal management strategy for SAAs is not well defined. OBJECTIVE: To review the institutional experience of five patients with isolated SAAs. METHODS: Five cases of isolated SAAs were identified at our institution, including two cases with multiple simultaneous SAAs. Clinical presentation, imaging, and management strategies for each case were reviewed. A literature review of all SAAs reported between 1950 and 2020 was performed. RESULTS: A total of five patients with eight isolated SAAs presented to our institution: one aneurysm was lumbar in location, while the remaining seven were thoracic. Two patients were treated with glue embolization followed by laminectomy for hematoma evacuation; one was treated with only surgery; and the other two, which both had multiple lesions, were managed conservatively with interval complete regression of their aneurysms. All five patients had good neurological outcomes. Literature review found 124 patients with at least 137 isolated SAAs and revealed treatment strategies including conservative management, glue or coil embolization, muslin wrapping, and surgical resection or clipping. CONCLUSION: Multiple management strategies exist for SAAs, and clinical consideration of patient presentation and lesion morphology determine appropriate strategy. Our case series demonstrates three of these treatment paradigms.

Acute Subdural Hematoma Associated with Aneurysmal Rupture: A Case Series and Review of Literature.

BACKGROUND: Ruptured cerebral aneurysms represent a neurosurgical emergency with characteristic clinical presentation and imaging findings. However, atypical presentations may occur in association with acute subdural hematomas (SDHs). METHODS: A retrospective review was conducted at our institution between 2013 and 2021 to identify patients with aneurysmal rupture presenting with SDH. Cases were reviewed for clinical presentation, imaging findings, management, and outcome. RESULTS: A total of 8 patients were included in this review with an average age of 48.5 years. Six patients were women. The average Glasgow coma scale upon arrival was 6.3, and the Hunt-Hess average grade was 4.6. Aneurysm locations included posterior communicating artery (n = 3), anterior communicating artery (n = 2), middle cerebral artery (n = 2), and internal carotid artery terminus (n = 1). The size of aneurysm varied between 3 and 11 mm. Seven patients required surgical intervention, either craniotomy or craniectomy for hematoma evacuation, and aneurysms were treated by coiling (n = 2) or clipping (n = 6). CONCLUSIONS: Ruptured aneurysms may present with SDH with or without significant subarachnoid hemorrhage. This illustrative case series highlights this challenging presentation and the importance of early recognition and appropriate management.

Vessel wall imaging and quantitative flow assessment in arteriovenous malformations: A feasibility study.

INTRODUCTION: Cerebral arteriovenous malformations (AVMs) carry a rupture rate of 2-3% per year. Several architectural factors may influence rupture rate, and a recently theorized model of AVMs describes the influence of vessel wall inflammation. A novel imaging modality, vessel wall imaging (VWI), has been developed to view inflammatory processes in vessel wall foci but has not yet been examined in AVMs, which is the aim of this study. METHODS: This retrospective review studies prospectively collected data on patients with ruptured and unruptured AVMs between 2019 and 2021. Inclusion criteria included adult patients (≥18 years) with radiographically diagnosed AVM who underwent VWI. Charts were reviewed for medical history, clinical presentation, hospital course, discharge condition, and follow-up. Angioarchitectural features, blood flow, and VWI were compared in patients with and without hemorrhagic patients. RESULTS: Nine patients underwent VWI, mean age 37.7 ± 9.9 years. Four presented with hemorrhage (44.4%). Seven (77.7%) received glue embolization and 6 (66.7%) underwent surgical resection. All patients (4/4) with a history of hypertension presented with hemorrhage (p = 0.0027). Size and Spetzler-Martin grade were not associated with hemorrhage (p = 0.47, p = 0.59). Net AVM flow was higher in patients presenting with hemorrhage, although nonsignificant (p = 0.19). With VWI, 3 (75%) hemorrhagic AVMs showed visible nidus and draining veins, and all three demonstrated positive post-contrast wall enhancement in at least one of their draining veins; conversely, of fivenonhemorrhagic AVMs, only 2 (40%) demonstrated post-contrast wall enhancement in any draining vein (p = 0.090). CONCLUSION: This pilot study successfully demonstrated capture of venous walls in AVMs using VWI. In this study, draining vein enhancement occurred more often in hemorrhagic AVM and in those with higher venous volumetric flow.

Brain arteriovenous malformation flow after stereotactic radiosurgery: Role of quantitative MRA.

BACKGROUND: Stereotactic radiosurgery (SRS) is a current therapeutic option for treatment of arteriovenous malformations (AVMs) located in deep or eloquent brain regions. Obliteration usually occurs in a delayed fashion, with an expected latency of 3-5 years. Here, we assess how AVM flow correlates with volume before and after SRS treatment. METHODS: Patients with supratentorial AVM treated with SRS at our institution between 2012-2022 were retrospectively reviewed. Patients were included if Quantitative Magnetic Resonance Angiography (QMRA) study was performed at baseline and at least at the first follow-up. Correlation between AVM flow and volume before and after treatment was evaluated. AVM flow and volume were additionally assessed for obliteration using the non-parametric receiver operating characteristic (ROC) curve. RESULTS: Twelve patients with radiologic follow-up imaging were included. Eight patients presented AVM rupture, one of which occurred after radiosurgical treatment. Three patients underwent embolization prior SRS. Mean AVM initial volume was 3.8 cc (0.1-12.4 cc), mean initial flow 174 ml/min (11-604 ml/min), both variables showed progressive reduction at follow-up (range 3-57 months); and flow decreased with volume reduction (p < 0.001). Area under the ROC was 0.914 for both AVM flow and volume with obliteration (p = 0.019). CONCLUSIONS: AVM flow significantly decreased after SRS treatment, reflecting volume reduction. Baseline AVM flow and volume both predicted obliteration. QMRA provides additional non-invasive information to monitor patients after radiosurgical treatment.

Selective endovascular treatment of cervical arterial dissection using quantitative magnetic resonance angiography.

INTRODUCTION: The role of endovascular treatment in cervical artery dissection (CAD) is equivocal. This study compared cerebral blood flow in CAD between medically and endovascularly treated patients using quantitative magnetic resonance angiography (QMRA). METHODS: Retrospective chart review was completed for patients with CAD. Inclusion criteria were adults (>18 years) with diagnosis of dissection of the internal carotid artery or vertebral artery who received QMRA. The cases were reviewed for clinical presentation, diagnosis, management, and imaging, and in particular, patients who underwent endovascular treatment were evaluated. RESULTS: Forty-one patients were included, 46.3% female and mean age 46.0+/- 11.9 years. 21 patients (51.2%) had contralateral (ICA) dissections while 19 (46.3%) had vertebral artery (VA) dissections, and 1 had both involved. Five patients underwent stenting, angioplasty, or both. Baseline characteristics between patients who underwent medical versus endovascular treatment were similar, although patients undergoing stenting/angioplasty were more likely to have diabetes (p = 0.015) and prior anticoagulation use (p = 0.007). All endovascular patients demonstrated ischemia on MRI versus 53.1% of those undergoing medical management (p = 0.047). Comparing ipsilateral vessel flow over time in these two patient groups showed those who underwent stenting or angioplasty had lower baseline flows, albeit non-significant (p = 0.629). Patients who underwent endovascular treatment had lower distal flow compared to the medical management group. CONCLUSION: This study represents the first to assess vessel flow using QMRA in patients who underwent endovascular treatment of CAD. In combination with progressive symptoms, QMRA may serve as a useful adjunct in the selection of patients for endovascular intervention in arterial dissections.

External carotid artery to internal carotid artery transposition to augment flow for a superficial temporal artery to middle cerebral artery bypass associated with severe external carotid artery stenosis.

BACKGROUND: Donor vessel quality can impact the outcome of extracranial-intracranial (EC-IC) bypass. External carotid artery (ECA) disease may produce embolism into the anastomosis and cerebral territory and possibly reduce flow in the superficial temporal artery (STA). Previously reported remedies to ECA stenosis include ECA endarterectomy, stenting, and angioplasty. Clinical presentation A middle-aged patient with chronic left MCA occlusion, progressive ischemic symptoms on maximal medical therapy, and imaging confirmation of compromised hemodynamic reserve was evaluated for EC-IC bypass. Angiography demonstrated severe ECA origin stenosis. An ECA-ICA transposition was performed, primarily to eliminate the risk of emboli and secondarily to possibly improve the STA flow. The patient sustained an excellent radiological and clinical outcome, and the STA donor cut-flow was increased modestly by 22% (45 to 55 mL/min). CONCLUSION: This case is the first report of an ECA to internal carotid artery transposition as an option in the management of ECA stenosis in preparation for an STA-MCA bypass for the purpose of flow augmentation.