The role of surgical disconnection for posterior fossa pial arteriovenous fistulas and dural fistulas with pial supply: an illustrative case series.

BACKGROUND: Pial arteriovenous fistulas (pAVFs) are rare vascular malformations characterized by high-flow arteriovenous shunting involving a cortical arterial supply directly connecting to venous drainage without an intermediate nidus. Dural arteriovenous fistulas (dAVFs) can infrequently involve additional pial feeders which can introduce higher flow shunting and increase the associated treatment risk. In the posterior fossa, arteriovenous fistula (AVF) angioarchitecture tends to be particularly complex, involving either multiple arterial feeders-sometimes from both dural and pial origins-or small caliber vessels that are difficult to catheterize and tend to be intimately involved with functionally critical brainstem or upper cervical cord structures. Given their rarity, published experience on microsurgical or endovascular treatment strategies for posterior fossa pAVFs and dAVFs with pial supply remains limited. METHODS: Retrospective chart review from 2019-2023 at a high-volume center identified six adult patients with posterior fossa pAVFs that were unable to be fully treated endovascularly and required microsurgical disconnection. These cases are individually presented with a technical emphasis and supported by comprehensive angiographic and intraoperative images. RESULTS: One vermian (Case 1), three cerebellopontine angle (Cases 2-4) and two craniovertebral junction (Cases 5-6) posterior fossa pAVFs or dAVFs with pial supply are presented. Three cases involved mixed dural and pial arterial supply (Cases 1, 4, and 6), and one case involved a concomitant microAVM (Case 2). Endovascular embolization was attempted in four cases (Cases 1-4): The small caliber and tortuosity of the main arterial feeder prevented catheterization in two cases (Cases 1 and 3). Partial embolization was achieved in Cases 2 and 4. In Cases 5 and 6, involvement of the lateral spinal artery or anterior spinal artery created a prohibitive risk for endovascular embolization, and surgical clip ligation was pursued as primary management. In all cases, microsurgical disconnection resulted in complete fistula obliteration without evidence of recurrence on follow-up imaging (mean follow-up 27.1 months). Two patients experienced persistent post-treatment sensory deficits without significant functional limitation. CONCLUSIONS: This illustrative case series highlights the technical difficulties and anatomical limitations of endovascular management for posterior fossa pAVFs and dAVFs with pial supply and emphasizes the relative safety and utility of microsurgical disconnection in this context. A combined approach involving partial preoperative embolization-when the angioarchitecture is permissive-can potentially decrease surgical morbidity. Larger studies are warranted to better define the role for multimodal intervention and to assess associated long-term AVF obliteration rates in the setting of pial arterial involvement.

Impact of Cerebral Revascularization on Pial Collateral Flow in Patients With Unilateral Moyamoya Disease Using Quantitative Magnetic Resonance Angiography.

BACKGROUND AND OBJECTIVES: Moyamoya disease (MMD) is a chronic steno-occlusive disease of the intracranial circulation that depends on neoangiogenesis of collateral vessels to maintain cerebral perfusion and is primarily managed with cerebral revascularization surgery. A quantitative assessment of preoperative and postoperative collateral flow using quantitative magnetic resonance angiography with noninvasive optimal vessel analysis (NOVA) was used to illustrate the impact of revascularization on cerebral flow distribution. METHODS: A retrospective review of patients with unilateral MMD who underwent direct, indirect, or combined direct/indirect cerebral revascularization surgery was conducted between 2011 and 2020. Using NOVA, flow was measured at the anterior cerebral artery (ACA), ACA distal to the anterior communicating artery (A2), middle cerebral artery (MCA), posterior cerebral artery (PCA), and PCA distal to the posterior communicating artery (P2). Pial flow (A2 + P2) and collateral flow (ipsilateral [A2 + P2])-(contralateral [A2 + P2]) were measured and compared before and after revascularization surgery. Total hemispheric flow (MCA + A2 + P2) with the addition of the bypass graft flow postoperatively was likewise measured. RESULTS: Thirty-four patients with unilateral MMD underwent cerebral revascularization. Median collateral flow significantly decreased from 68 to 39.5 mL/min (P = .007) after bypass. Hemispheres with maintained measurable bypass signal on postoperative NOVA demonstrated significant reduction in median collateral flow after bypass (P = .002). Median total hemispheric flow significantly increased from 227 mL/min to 247 mL/min (P = .007) after bypass. Only one patient suffered an ipsilateral ischemic stroke, and no patients suffered a hemorrhage during follow-up. CONCLUSION: NOVA measurements demonstrate a reduction in pial collateral flow and an increase in total hemispheric flow after bypass for MMD, likely representing a decrease in leptomeningeal collateral stress on the distal ACA and PCA territories. Further studies with these measures in larger cohorts may elucidate a role for NOVA in predicting the risk of ischemic and hemorrhagic events in MMD.

Single-center outcomes of Onyx Frontier™ and Resolute Onyx™ drug-eluting balloon-mounted stents for rescue stenting for acute large vessel occlusion.

BACKGROUND: In cases where mechanical thrombectomy (MT) fails, rescue stenting may be necessary to achieve reperfusion; however, the lack of standardized techniques or devices poses a challenge. This series aims to present our early experience with the Onyx Frontier™ and Resolute Onyx™ balloon-mounted drug-eluting stents for rescue stenting. METHODS: A retrospective chart review was performed of all patients who underwent rescue stenting, in the setting of failed MT, using Onyx Frontier™ or Resolute Onyx™ stents at a single institution. Technical details, procedural complications, and patient outcomes were recorded for each case. RESULTS: Twenty-two Onyx Frontier™ and Resolute Onyx™ stents were deployed in 18 patients undergoing rescue stenting. Stent locations included the middle cerebral artery (36.4%), internal carotid artery (18.2%), vertebral artery (22.7%), and basilar artery (22.7%). The average National Institutes of Health Stroke Scale score before MT was 13.8 (range 0-31). The median initial modified Rankin Scale (mRS) score was zero, while the median mRS score at follow-up was three. Successful reperfusion, as assessed by TICI scores, was achieved in 43.8% of patients for TICI 3, 43.8% for TICI 2C, and 12.5% for TICI 2B. Post-revascularization, 16.7% of patients experienced hemorrhage, of which one patient (5.6%) had symptomatic hemorrhage. CONCLUSIONS: Onyx Frontier™ and Resolute Onyx™ stents are well suited for rescue stenting in cases of failed MT. These balloon-mounted drug-eluting stents exhibit excellent navigability, rendering them appropriate for rescue revascularization procedures. Our findings demonstrate that these stents confer a high degree of technical success.

Future of Endovascular and Surgical Treatments of Atherosclerotic Intracranial Stenosis.

Intracranial atherosclerotic disease and resultant intracranial stenosis is a global leading cause of stroke, and poses an ongoing treatment challenge. Among patients with intracranial stenosis, those with hemodynamic compromise are at high risk for recurrent stroke despite medical therapy and risk factor modification. Revascularization of the hypoperfused territory is the most plausible treatment strategy for these high-risk patients, yet surgical and endovascular therapies have not yet shown to be sufficiently safe and effective in randomized controlled trials. Advances in diagnostic and therapeutic technologies have led to a resurgence of interest in surgical and endovascular treatment strategies, with a growing body of evidence to support their further evaluation in the treatment of select patient populations. This review outlines the current and emerging endovascular and surgical treatments and highlights promising future management strategies.

Efficacy and Safety of Endoscopic Transsphenoidal Resection for Prolactinoma: A Retrospective Multicenter Case-series.

BACKGROUND: Endoscopic transsphenoidal surgery (ETSS) for prolactinoma is reserved for dopamine agonist (DA) resistance, intolerance, or apoplexy. High remission (overall 67%, microprolactinoma up to 90%), low recurrence (5-20%) rates highlighted that surgery might be first-line treatment. AIMS: To report on outcomes of ETSS in a cohort of prolactinomas. METHODS: Multicenter retrospective cohort of 137 prolactinoma patients (age 38.2 ± 13.7 years; 61.3% female, median follow-up 28.0 [15.0-55.5] months) operated between 2010-2019 with histopathological confirmation. RESULTS: Median preoperative prolactin levels were 166 (98-837 µg/L; males 996 [159-2145 µg/L] vs. females 129 [84-223 µg/L], p <0.001). 56 (40.9%) microprolactinomas, 69 (50.4%) macroprolactinomas, and 7 (5.1%) giant prolactinomas were included, whereas no adenoma was detected in 5 (3.6%) patients. Males had larger tumors (macroprolactinomas: 38, 71.7%) vs. 31 (36.9%), p <0.001; giant prolactinomas: 7 (13.2%) vs. 0 (0.0%), (p <0.001). Prolactinomas were graded as KNOSP-3 in 15 (11.5%), and KNOSP-4 in 20 (15.3%) patients. Primary indication was DA intolerance (59, 43.1%); males 14 (26.4%) vs. females 45 (53.6%), p = 0.006. Long-term remission (i.e., DA-free prolactin level <1xULN) was achieved in 87 (63.5%) patients, being higher in intended complete resection (69/92 [75.0%]), and lower in males (25 [47.2%] vs. 62 females [73.8%], p = 0.002). Transient DI (n = 29, 21.2%) was the most frequent complication. CONCLUSIONS: Despite high proportions of macroprolactinoma and KNOSP 3-4, long-term remission rates were 63.5% overall, and 83.3% in microprolactinoma patients. Males had less favorable remission rate compared to females. These findings highlight that ETSS may be a safe and efficacious treatment to manage prolactinoma.

Postoperative stereotactic radiosurgery for intracranial solitary fibrous tumors: systematic review and pooled quantitative analysis.

BACKGROUND: Intracranial solitary fibrous tumors (SFTs), formerly hemangiopericytomas (HPCs), are rare, aggressive dural-based mesenchymal tumors. While adjuvant radiation therapy has been suggested to improve local tumor control (LTC), especially after subtotal resection, the role of postoperative stereotactic radiosurgery (SRS) and the optimal SRS dosing strategy remain poorly defined. METHODS: PubMed, EMBASE, and Web of Science were systematically searched according to PRISMA guidelines for studies describing postoperative SRS for intracranial SFTs. The search strategy was defined in the authors' PROSPERO protocol (CRD42023454258). RESULTS: 15 studies were included describing 293 patients harboring 476 intracranial residual or recurrent SFTs treated with postoperative SRS. At a mean follow-up of 21-77 months, LTC rate after SRS was 46.4-93% with a mean margin SRS dose of 13.5-21.7 Gy, mean maximum dose of 27-39.6 Gy, and mean isodose at the 42.5-77% line. In pooled analysis of individual tumor outcomes, 18.7% of SFTs demonstrated a complete SRS response, 31.7% had a partial response, 18.9% remained stable (overall LTC rate of 69.3%), and 30.7% progressed. When studies were stratified by margin dose, a mean margin dose > 15 Gy showed an improvement in LTC rate (74.7% versus 65.7%). CONCLUSIONS: SRS is a safe and effective treatment for intracranial SFTs. In the setting of measurable disease, our pooled data suggests a potential dose response of improving LTC with increasing SRS margin dose. Our improved understanding of the aggressive biology of SFTs and the tolerated adjuvant SRS parameters supports potentially earlier use of SRS in the postoperative treatment paradigm for intracranial SFTs.

Flow diverter surface modifications for aneurysm treatment: A review of the mechanisms and data behind existing technologies.

Flow diversion (FD) has become a mainstay treatment for large wide-necked aneurysms. Despite excellent safety and efficacy, the risk of thromboembolic complications necessitates the use of dual antiplatelet therapy (DAPT). The use of DAPT makes hemorrhagic complications of stenting carry high morbidity and mortality. Additionally, DAPT usage carries a risk of "nuisance" complications that do not directly impact intracranial circulation but need to be managed nonetheless. To circumvent this issue, the most recent generation of flow diverters have undergone surface modification with various compounds to confer blood compatibility to limit clotting and thrombosis. While these newer generation flow diverters are marketed to enhance ease of deployment, the goal is to eventually facilitate single antiplatelet use with flow diverter treatment. This generation of FDs have potential to expand indications beyond unruptured wide-necked aneurysms to include ruptured intracranial aneurysms without the necessity of DAPT. Currently, no comprehensive review details the molecular mechanisms and pre-clinical and clinical data on these modifications. We seek to fill this gap in the literature by consolidating information on the coating technology for four major FDs currently in clinical use-PipelineTM Flex and Vantage Shield TechnologyTM, FREDTMX, p48/64 hydrophilic coating, and Acandis Dervio® 2heal-to serve as a reference guide in neurointerventional aneurysm treatment. Although the Balt silkTM was one of the first FDs, it is uncoated, thus we will not cover this device in our review. A literature review was performed to obtain information on each coating technology for the major flow diverters currently on the market using international databases (PUBMED, Embase, Medline, Google Scholar). The search criteria used the keywords for each coating technology of interest "phosphorylcholine," "poly 2-methoxyethyl acrylate," "hydrophilic polymer coating," and "fibrin-heparin" Keywords related to the device names "Pipeline Shield," "Pipeline Shield with Flex Technology," "FRED," "FREDX," "p64," "p64-HPC," "Derivo 2heal" were also used. Studies that detailed the mechanism of action of the coating, any pre-clinical studies with surface-modified intravascular devices, and any clinical retrospective series, prospective series, or randomized clinical trials with surface-modified devices for aneurysm treatment were included.

Anterior-posterior diameter is a key driver of resectability and complications for pituitary adenomas with suprasellar extension in endoscopic transsphenoidal surgery.

BACKGROUND: As endoscopic transsphenoidal approaches are more routinely selected for progressively larger pituitary adenomas with parasellar extension, understanding potential anatomical factors that limit resection and contribute to complications is becoming increasingly important for tailoring a surgical approach. This study aimed to reevaluate existing predictive tools for resectability in pituitary adenomas specifically with suprasellar extension, and furthermore identify any additional measurable features that may be more useful in preoperative planning. METHODS: A single-center retrospective chart review of adult patients who underwent endoscopic transsphenoidal surgery for pituitary adenomas with suprasellar extension from 2015 to 2020 was performed. Preoperative MRIs were systematically assessed to assign a Knosp classification, a Zurich Pituitary Score (ZPS), and for dimensional measurements of the suprasellar aspect of the lesions. Univariate comparisons and multivariate regression models were employed to assess the influence of these factors on extent of resection and postoperative complications. RESULTS: Of the 96 patients with suprasellar pituitary adenomas who underwent endoscopic transsphenoidal surgery, 74 patients (77%) had a gross total resection (GTR). Neither Knosp grade nor ZPS score, even when dichotomized, demonstrated an association with GTR (Knosp 3A-4 versus Knosp 0-2, p = 0.069; ZPS III-IV versus ZPS I-II, p = 0.079). Multivariate regression analysis identified suprasellar anterior-posterior tumor diameter (SSAP) as the only significant predictor of extent of resection in this cohort (OR 0.951, 95% CI 0.905-1.000, p = 0.048*). A higher SSAP also had the strongest association with intraoperative CSF leaks (p = 0.0012*) and an increased overall rate of postoperative complications (p = 0.002*). Further analysis of the regression model for GTR suggested an optimal cut point value for SSAP of 23.7 mm, above which predictability for failing to achieve GTR carried a sensitivity of 89% and a specificity of 41%. CONCLUSIONS: This study is unique in its examination of endoscopic transsphenoidal surgical outcomes for pituitary adenomas with suprasellar extension. Our findings suggest that previously established grading systems based on lateral extension into the cavernous sinus lose their predictive value in lesions with suprasellar extension and, more specifically, with increasing suprasellar anterior-posterior diameter.

Hemodynamic outcomes of stenting for vertebrobasilar insufficiency in patients with a low flow state.

INTRODUCTION: The Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) study determined patients with low flow in their vertebrobasilar (VB) system are at increased risk of recurrent stroke. Endovascular interventions such as angioplasty and stenting are reserved for patients with refractory symptoms; however, few series to date have demonstrated either hemodynamic or clinical outcomes in this high-risk patient group. We present our combined institutional series of patients with symptomatic VB atherosclerotic disease and low-flow state who underwent angioplasty and stenting. METHODS: Retrospective chart review of patients undergoing angioplasty and stenting for symptomatic VB atherosclerotic disease at two institutions was performed. Clinical and radiographical outcomes were collected including flow rates using quantitative MRA (QMRA) pre- and post-stenting. RESULTS: Seventeen patients underwent angioplasty and stenting for symptomatic VB atherosclerotic disease and met VERiTAS low-flow state criteria. There were four cases (23.5%) of periprocedural stroke, two of which were minor and transient. The stent was placed intracranially in 82.4% of patients. Basilar and bilateral posterior cerebral artery (PCA) flows significantly improved post-stenting (p < 0.05) and normalized based upon VERiTAS criteria in all patients. Fourteen patients had delayed QMRA at mean follow-up 20 months demonstrating appropriate patency and flow post-stenting. Two patients (10%) had recurrent stroke, one from medication nonadherence and in-stent thrombosis, and the other from a procedural dissection that subsequently became symptomatic. CONCLUSIONS: Our series demonstrates angioplasty and stenting significantly improve intracranial flow over long-term. Angioplasty and stenting may improve the natural history of low-flow VB atherosclerotic disease.

A comparison of endovascular coil systems for the treatment of small intracranial aneurysms.

BACKGROUND: Endovascular coiling of small, intracranial aneurysms remains controversial and difficult, despite advances in technology. METHODS: We retrospectively reviewed data for 62 small aneurysms (<3.99 mm) in 59 patients. Occlusion rates, complications rates, and coil packing densities were compared between subgroups based upon coil type and rupture status. RESULTS: Ruptured aneurysms predominated (67.7%). Aneurysms measured 2.99 ± 0.63 mm by 2.51 ± 0.61 mm with an aspect ratio of 1.21 ± 0.34 mm. Brands included Optima (Balt) (29%), MicroVention Hydrogel (24.2%), and Penumbra SMART (19.4%) coil systems. Average packing density was 34.3 ± 13.5 mm3. Occlusion rate was 100% in unruptured aneurysms; 84% utilized adjuvant devices. For ruptured aneurysms, complete occlusion or stable neck remnant was achieved in 88.6% while recanalization occurred in 11.4%. No rebleeding occurred. Average packing density (p = 0.919) and coil type (p = 0.056) did not impact occlusion. Aspect ratio was smaller in aneurysms with technical complications (p = 0.281), and aneurysm volume was significantly smaller in those with coil protrusion (p = 0.018). Complication rates did not differ between ruptured and unruptured aneurysms (22.6 vs. 15.8%, p = 0.308) or coil types (p = 0.830). CONCLUSION: Despite advances in embolization devices, coiling of small intracranial aneurysms is still scrutinized. High occlusion rates are achievable, especially in unruptured aneurysms, with coil type and packing density suggesting association with complete occlusion. Technical complications may be influenced by aneurysm geometry. Advances in endovascular technologies have revolutionized small aneurysm treatment, with this series demonstrating excellent aneurysm occlusion especially in unruptured aneurysms.

Woven EndoBridge Device Migration and Microsnare Retrieval Strategy: Single Institutional Case Reports with Technical Video Demonstration.

The Woven EndoBridge (WEB) (MicroVention/Terumo) device is a treatment option for wideneck bifurcation aneurysms. An uncommon adverse effect is WEB device migration. While certain bailout strategies for WEB recovery have been described, there is still a paucity of information on optimal strategies to maximize both short and long-term post-operative outcomes. We add 2 cases at our institution to the existing literature of WEBectomy in the setting of complicated intracranial aneurysm treatment. We discuss the long-term imaging outcomes with additional fluoroscopy video demonstrating our technique. Our findings reflect a clear benefit for the use of the Amplatz GooseneckTM microsnare (Medtronic) device as a means of WEB recovery, coupled with potential stent-assisted WEB embolization to remove the aneurysm from the parent circulation, while minimizing recurrence and thromboembolic complications.

Comparative outcomes of the treatment of unruptured paraophthalmic aneurysms in the era of flow diversion.

BACKGROUND: Paraophthalmic aneurysms present a challenge to surgeons and their ideal management remains up for debate. We studied recent outcomes of these lesions in a single center. METHODS: A retrospective chart review of all patients undergoing treatment for paraophthalmic aneurysms from 2017-2019 was performed. Factors including patient demographics, aneurysm characteristics, treatment modality, radiographic treatment outcome, clinical outcome, and length of stay were collected, and bivariate analysis was performed. RESULTS: In total 84.5% (82/97) of aneurysms were treated endovascularly and 15.5% (15/97) surgically. In the surgery cohort, there were three transient perioperative complications (20%) and one minor postoperative complication (6.7%). Complete aneurysm occlusion or near complete (<2mm residual) was achieved in 100% (15/15). All but one patient had mRS ≤1 at the last follow-up. In the endovascular group, 78.1% (64/82) underwent flow diversion alone. Endovascular treatment was associated with a 4.9% (4/82) rate of periprocedural complications: 3 transient events, and 1 death, and a 3.7% (3/82) rate of delayed complications: 2 transient vision changes, and one death. Rate of total occlusion was 87.8% (72/82). 76 patients (92.7%) had mRS ≤1 at the last follow-up. Length of stay was significantly shorter in the endovascular group (3.4 days vs. 7.0 days) [p < 0.001]. CONCLUSIONS: This series demonstrates similar safety to previously reported series as well as the efficacy of both surgical clipping and endovascular embolization of paraophthalmic aneurysms. Rate of complications and treatment efficacy were similar in both groups although this represents a single institution series not generalizable to all centers.

Disappearance of a small unruptured intracranial aneurysm: A case report and brief literature review.

Disappearing intracranial aneurysms are rare and have not been extensively reported in the literature. They are often small or partially thrombosed and carry a significant risk of recurrence. We discuss a unique case of a 65-year-old woman who presented in 2006 with a subarachnoid hemorrhage and was found to have a ruptured posterior communicating artery and an unruptured P1 aneurysm. Follow-up angiography and imaging showed no changes in the size of a left P1 aneurysm for 11 years (2006-2017). However, in 2021, 15 years after initial presentation, no aneurysm was seen on magnetic resonance angiography, and subsequent digital subtraction angiography in 2022 showed almost complete disappearance of the unruptured P1 aneurysm. Literature review reveals only six reported cases during which a small, unruptured anterior circulation aneurysm disappeared, or regressed on follow-up imaging and no reported cases in the posterior circulation.

FLAIR hyperintense vessels on MRI post brain arteriovenous malformation embolization: A novel finding associated with post-procedure intraparenchymal hemorrhage.

INTRODUCTION: Brain arteriovenous malformations (BAVMs) are frequently managed by endovascular embolization with a growing number of centers embolizing with intent to cure. Hemorrhage post-embolization is a severe and poorly understood complication. We present a novel imaging finding associated with post-embolization hemorrhage that has significantly impacted the management of patients at our institution. METHODS: A retrospective review of all patients undergoing embolization of BAVM at a single center was performed. Post-embolization magnetic resonance imaging (MRI) was reviewed for the presence of T2 fluid-attenuated inversion recovery (FLAIR) hyperintense vessels (FHVs). Bivariate analysis was performed to determine associations between patient characteristics and risk of hemorrhage. RESULTS: A total of 50 patients underwent 75 embolization procedures. Forty-six post-embolization MRIs were available for review. There were four hemorrhages and 100% of those presented with FHV. In contrast, only 11.9% of embolization procedures without post-procedural hemorrhage had FHVs on MRI. In total, 18.7% of embolizations led to some morbidity or mortality, with only 6.7% leading to permanent morbidity or mortality. In bivariate analysis, only the presence of FHVs was correlated with the risk of hemorrhage (p < 0.05). CONCLUSIONS: This is the first series to describe the finding of hyperintense blood vessels on FLAIR imaging after embolization of BAVMs and correlate it with hemorrhage post embolization. This finding can help guide practitioners and potentially identify patients at risk of delayed hemorrhage post embolization.

Quantitative magnetic resonance angiography as an alternative imaging technique in the assessment of cerebral vasospasm after subarachnoid hemorrhage.

INTRODUCTION: The major mechanism of morbidity of delayed cerebral ischemia after subarachnoid hemorrhage (SAH) is considered to be severe vasospasm. Quantitative MRA (QMRA) provides direct measurements of vessel-specific volumetric blood flow and may permit a clinically relevant assessment of the risk of ischemia secondary to cerebral vasospasm. PURPOSE: To evaluate the utility of QMRA as an alternative imaging technique for the assessment of cerebral vasospasm after SAH. METHODS: QMRA volumetric flow rates of the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) were compared with vessel diameters on catheter-based angiography. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of QMRA for detecting cerebral vasospasm was determined by receiver-operating characteristic curves. Spearman correlation coefficients were calculated for QMRA flow versus angiographic vessel diameter. RESULTS: Sixty-six vessels (10 patients) were evaluated with QMRA and catheter-based angiography. The median percent QMRA flow of all vessels with angiographic vasospasm (55.0%, IQR 34.3-71.6%) was significantly lower than the median percent QMRA flow of vessels without vasospasm (91.4%, IQR 81.4-100.4%) (p < 0.001). Angiographic vasospasm reduced QMRA-assessed flow by 23 ± 5 (p = 0.018), 95 ± 12 (p = 0.042), and 16 ± 4 mL/min (p = 0.153) in the ACA, MCA, and PCA, respectively, compared to vessels without angiographic vasospasm. The sensitivity, specificity, PPV, and NPV of QMRA for the discrimination of cerebral vasospasm was 84%, 72%, 84%, and 72%, respectively, for angiographic vasospasm >25% and 91%, 60%, 87%, and 69%, respectively, for angiographic vasospasm >50%. The Spearman correlation indicated a significant association between QMRA flows and vessel diameters (rs = 0.71, p < 0.001). CONCLUSION: Reduction in QMRA flow correlates with angiographic vessel narrowing and may be useful as a non-invasive imaging modality for the detection of cerebral vasospasm after SAH.

Ventral Spinal Cord Herniation Causing Spinal Intradural Hematoma and Subarachnoid Hemorrhage: A Case Report.

Ventral spinal cord herniation is a rare pathology, caused by a dural defect, that leads to progressive myelopathy. The true prevalence of ventral spinal cord herniation is unknown largely because of underdiagnosis due to its nonspecific symptoms. Though there are theories that attempt to describe how these dural defects are formed, the true causes of these defects are unknown. In this case report, we present a case of a 29-year-old female who had an idiopathic ventral spinal cord herniation causing an intradural hematoma and subarachnoid hemorrhage. This is the first reported case of spinal cord herniation causing hemorrhage.

Angiographic Treatment of Asymptomatic Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage for the Prevention of Delayed Cerebral Ischemia.

OBJECTIVE: Angiographic treatment of asymptomatic cerebral vasospasm (CVS) in aneurysmal subarachnoid hemorrhage remains controversial. We sought to investigate its relationship with the development of delayed cerebral ischemia. METHODS: Consecutive patients admitted between July 2017 and June 2019, with a diagnosis of aneurysmal subarachnoid hemorrhage, were retrospectively analyzed. The rate of development of delayed cerebral ischemia was compared between a group of patients who underwent cerebral angiography for asymptomatic CVS and those who did not. The Mann-Whitney U test or χ2 test was used to compare the 2 groups. RESULTS: Thirty-seven of the 94 patients with aneurysmal subarachnoid hemorrhage were screened for CVS, of whom 16 (43%) had moderate-severe vasospasm. When patients who underwent therapeutic cerebral angiography were compared with those who did not and after adjusting for sex, age, and grade of subarachnoid hemorrhage, treatment was not found to be significantly associated with delayed cerebral ischemia (hazard ratio = 0.82, 95% confidence interval: 0.19-3.52, P = 0.79). We found that the median length of stay in the intensive care unit and hospital increased significantly with the severity of CVS (P < 0.001). CONCLUSIONS: Cerebral angiography has a low rate of detecting moderate-severe CVS in asymptomatic patients. Moreover, there was no statistically significant difference in the rate of delayed cerebral ischemia between asymptomatic patients treated versus those not treated for CVS. There was significant association between the severity of CVS and the intensive care unit and hospital length of stay. More studies are needed to evaluate the utility of treating asymptomatic CVS in high-grade aneurysmal subarachnoid hemorrhage.