Mechanical Thrombectomy for Acute Ischemic Stroke: Considerations in Children.

The use of mechanical thrombectomy for the treatment of acute childhood arterial ischemic stroke with large vessel occlusion is increasing, with mounting evidence for its feasibility and safety. Despite this emerging evidence, clear guidelines for patient selection, thrombectomy technique, and postprocedure care do not exist for the pediatric population. Due to unique features of stroke in children, neurologists and interventionalists must consider differences in patient size, anatomy, collateral vessels, imaging parameters, and expected outcomes that may impact appropriate patient selection and timing criteria. In addition, different causes of stroke and comorbidities in children must be considered and may alter the safety and efficacy of thrombectomy. To optimize the success of endovascular intervention in children, a multidisciplinary team should take into account these nuanced considerations when determining patient eligibility, developing a procedural approach, and formulating a postprocedure neurological monitoring and therapeutic plan.

Removal of Antiscatter Grids for Spinal Digital Subtraction Angiography: Dose Reduction without Loss of Diagnostic Value.

Background Spinal digital subtraction angiography (DSA) exposes patients and operators to substantial amounts of radiation. Antiscatter grid (ASG) removal is used to decrease radiation exposure but may reduce image quality. Purpose To determine whether ASG removal during spinal DSA in adults reduces radiation dose while maintaining diagnostic image quality and whether dose reduction is related to body mass index (BMI). Materials and Methods This Health Insurance Portability and Accountability Act-compliant prospective study included adults undergoing spinal DSA between January and December 2016. Each procedure included an additional angiographic acquisition performed twice, once with and once without ASG, either documenting the artery of Adamkiewicz (no pathology group) or the condition leading to the procedure (pathology group). Dose differences between study acquisitions and the influence of BMI were evaluated via paired t test. Two neurointerventionalists blinded to acquisition protocols were asked to independently evaluate a sample of 40 study acquisitions (20 with ASG, 20 without ASG) from 20 randomly selected participants to (a) rate image quality, (b) categorize findings, and (c) determine whether images had been obtained with or without ASG. Percentage agreement on image quality, findings categorization, and ability to correctly identify the acquisition protocol was calculated for both readers. Results Fifty-three participants (mean age ± standard deviation, 51 years ± 15.2; 32 men) were evaluated. ASG removal reduced the mean dose per acquisition by approximately 33% (mean dose-area product and air kerma decreased from 202 to 135.6 µGy/m2 and from 35.3 to 24 mGy, respectively; P < .001) independently of BMI (P = .3). Both readers evaluated all images (40 of 40) as being of diagnostic quality and correctly categorized findings in 19 of 20 (95%) cases. Overall percentage agreement for correct protocol identification was 60% (12 of 20) for grid-in and 45% (nine of 20) for grid-out images. Conclusion Antiscatter grid removal during spinal digital subtraction angiography decreased participants' radiation exposure while preserving diagnostic image quality. © RSNA, 2020.

Atlanto-occipital ligament calcification: a novel imaging finding in pediatric rotational vertebral artery occlusion.

We describe a 2-year-old girl with bow hunter syndrome complicated by vertebral artery dissection and multiple ischemic infarcts. Pediatric bow hunter syndrome is a rare and likely under-recognized disorder. Interestingly, our patient had atlanto-occipital ligament calcification on CT scan, an imaging finding that has not been reported in association with bow hunter syndrome and one that might help increase recognition of this dynamic disorder of the posterior circulation.

An Interdisciplinary Approach to Treatment of Adult Facial Arteriovenous Malformations: A Review of the Literature and A Single Institution's Experience With "Late" Surgical Resection and Aesthetic Reconstruction.

BACKGROUND: Arteriovenous malformations (AVMs) are high flow vascular anomalies that are difficult to manage given their high recurrence rate. At this time, the optimal treatment of AVMs involves embolization and surgical resection. However, few studies have examined patient outcomes after a delayed surgical resection approach. METHODS: A retrospective chart review of all patients presenting to a single institution with vascular malformations from 2000 to 2016 was performed. Patients with facial AVMs that underwent operative management were included. Records were reviewed for patient characteristics, lesion natural history, operative timing after embolization (<72 vs >72 hours), and outcomes. RESULTS: 11 patients fulfilled the inclusion/exclusion criteria. Nine patients were female, with an average age at resection of 29.1 years. Three patients had hemi/mid-facial AVMs, 1 patient had a nasal AVM, 3 patients had labial AVMs, 1 patient had an AVM on the chin, and 1 had a periorbital AVM. Average time between embolization and primary resection was 8.6 days (range 1-24). No complications requiring reoperation occurred in any patient. Average follow-up was 32.6 months, with 2 recurrences at a mean of 47.6 months. Timing of resection, Schobinger stage, and resection completeness did not significantly affect recurrence (P >0.05). Lesion size >6 cm in any dimension was significantly associated with recurrence (P = 0.018). CONCLUSION: Compared to early resection, delayed (>72 h) surgical resection after embolization of facial AVMs is a viable treatment option and results in non-inferior recurrence rates (25 vs 14% respectively over a 40-month period).

Susceptibility weighted imaging in infants with staged embolization of vein of Galen aneurysmal malformations.

BACKGROUND AND PURPOSE: The vein of Galen aneurysmal malformation (VGAM) is a rare congenital vascular malformation with a higher morbidity and mortality, especially in neonates. Ultrasound, CT and MR are usually used in diagnosis and treatment monitoring of these disorders. In this current study, we aim to examine utility of SWI in evaluation of treatment response in infants with VGAM. MATERIALS AND METHODS: We performed a retrospective chart analysis of children with VGAM in our institution between January 2008 and December 2016. Inclusion criteria included; confirmed VGAM on DSA; available SWI sequence at baseline and at follow up after at least a single embolization session; age at initial MR of 18 years or younger. Signal intensity and Angioarchitecture of VGAM and cerebral veins on SWI, as well as hydrocephalus and clinical outcome were evaluated. RESULTS: Of 11 patients identified with VGAM in our institution, 5 children (3 males and 2 females) satisfied the inclusion criteria. The average age at initial MR was 29 days (range 1-120). Fourteen MRI were available for review. All children had VGAM of mural type. Intramedullary veins were dilated and SWI-hypointense in all children, while subependymal and sulcal veins were dilated and SWI-hypointense in 4 patients on initial MRI. On the first available follow up MRI, cerebral veins have mostly normalized in 4 children and remained mostly dilated and SWI-hypointense in 1 child; even after complete treatment of the VGAM. CONCLUSION: Our preliminary findings show that SWI seems to offer a beneficial non-invasive tool in evaluating passive venous congestion patterns in pediatric patients with VGAM. It remains to be determined in larger studies, the clinical significance of these SWI changes.

Embolization of a traumatic arteriovenous fistula between the middle meningeal artery and middle meningeal vein in a child with pulsatile tinnitus.

Traumatic arteriovenous fistulas (AVFs) involving the middle meningeal artery (MMA) are uncommon lesions and rare in the pediatric population. An adolescent with headaches developed a bruit and a rhythmic "swooshing" noise in the left ear 9 weeks after a traumatic brain injury involving a left temporal bone fracture. An MRA of the brain demonstrated an enlarged left MMA and arterialized flow in the left middle meningeal vein (MMV), suggestive of an AVF. Cerebral angiography confirmed and characterized the left MMA-MMV fistula, which drained into the pterygoid plexus. The patient underwent transarterial coil embolization, with successful obliteration of the fistulous connection, and her tinnitus resolved. This case illustrates the importance of recognizing a post-traumatic AVF in a pediatric patient with pulsatile tinnitus, and that endovascular treatment by coil embolization is a safe and effective treatment option.

Pituitary Adenoma Apoplexy of the Orbit, Diagnosis, and Management With Presurgical Embolization.

Orbital invasion of pituitary adenomas has been previously reported. In this report, the authors describe a 71-year-old female with a prolactinoma that presented with invasion of and apoplexy within the orbit. The patient underwent exenteration, followed by rapid tumor recurrence and growth. Given the hemorrhagic nature of the tumor, she subsequently underwent preoperative embolization and surgical resection. This case is notable in that it illustrates both apoplexy of a pituitary tumor within the orbit and the benefit of presurgical embolization.

Cerebrofacial arteriovenous metameric syndrome (CAMS): a spectrum disorder of craniofacial vascular malformations.

Cerebrofacial arteriovenous metameric syndrome (CAMS) is a recent classification of vascular malformations that encompasses a spectrum of phenotypic expression involving arteriovenous malformations (AVMs) of the cerebral, orbital, and facial region. Recognizing the embryologic basis of CAMS is important for diagnosing other AVMs along the same metameric level. Visual loss is the most common presentation prompting ophthalmologic evaluation followed by neuroimaging. We present two pediatric patients with ipsilateral optic nerve and chiasmal AVMs without cutaneous manifestations, characteristic of CAMS 2. The diagnosis of cerebral AVMs was made by magnetic resonance imaging of the brain and confirmed with cerebral angiography. High-resolution flat-panel computed tomography was performed in one patient and was useful to demonstrate the intraneural invasion of the optic nerve by the AVM.

"Endovascular embolic hemispherectomy": a strategy for the initial management of catastrophic holohemispheric epilepsy in the neonate.

PURPOSE: Conflicting challenges abound in the management of the newborn with intractable epilepsy related to hemimegalencephaly. Early hemispherectomy to stop seizures and prevent deleterious consequences to future neurocognitive development must be weighed against the technical and anesthetic challenges of performing major hemispheric surgery in the neonate. METHODS: We hereby present our experience with two neonates with hemimegalencephaly and intractable seizures who were managed using a strategy of initial minimally invasive embolization of the cerebral blood supply to the involved hemisphere. RESULTS: Immediate significant seizure control was achieved after embolization of the cerebral blood supply to the involved hemisphere followed by delayed ipsilateral hemispheric resection at a later optimal age. CONCLUSION: The considerations and challenges encountered in the course of the management of these patients are discussed, and a literature review is presented.

Imaging the DNA Alkylator Melphalan by CEST MRI: An Advanced Approach to Theranostics.

Brain tumors are among the most lethal types of tumors. Therapeutic response variability and failure in patients have been attributed to several factors, including inadequate drug delivery to tumors due to the blood-brain barrier (BBB). Consequently, drug delivery strategies are being developed for the local and targeted delivery of drugs to brain tumors. These drug delivery strategies could benefit from new approaches to monitor the delivery of drugs to tumors. Here, we evaluated the feasibility of imaging 4-[bis(2-chloroethyl)amino]-l-phenylalanine (melphalan), a clinically used DNA alkylating agent, using chemical exchange saturation transfer magnetic resonance imaging (CEST MRI), for theranostic applications. We evaluated the physicochemical parameters that affect melphalan's CEST contrast and demonstrated the feasibility of imaging the unmodified drug by saturating its exchangeable amine protons. Melphalan generated a CEST signal despite its reactivity in an aqueous milieu. The maximum CEST signal was observed at pH 6.2. This CEST contrast trend was then used to monitor therapeutic responses to melphalan in vitro. Upon cell death, the decrease in cellular pH from ∼7.4 to ∼6.4 caused an amplification of the melphalan CEST signal. This is contrary to what has been reported for other CEST contrast agents used for imaging cell death, where a decrease in the cellular pH following cell death results in a decrease in the CEST signal. Ultimately, this method could be used to noninvasively monitor melphalan delivery to brain tumors and also to validate therapeutic responses to melphalan clinically.

A review of the literature for intra-arterial chemotherapy used to treat retinoblastoma.

Retinoblastoma is a malignancy of the retina that usually presents before the age of 5 years. Sporadic retinoblastoma is most often unilateral and with no hereditary influence, whereas familial retinoblastoma presents unilaterally or bilaterally in conjunction with genetic inheritance. Several treatments have been attempted with the goals of saving the child's life, salvaging the eye, and preserving vision. Alternative methods including external beam radiation, systemic chemotherapy and focal therapies have been shown to be effective but carry a risk of enucleation and other complications proportional to the severity of the tumor. Selective intra-arterial chemotherapy for retinoblastoma began in 1988 in Japan and has emerged in the last 7 years in the United States as a feasible, effective and minimally invasive treatment option. We review the retinoblastoma treatment literature focusing on intra-arterial chemotherapy.

Neuroimaging findings in children with Keutel syndrome.

BACKGROUND: Keutel syndrome is a rare autosomal-recessive condition characterized by abnormal cartilage calcification. Neuroimaging findings associated with this condition have been randomly described in the literature. OBJECTIVE: To systematically evaluate the neuroimaging findings in a series of children with Keutel syndrome to broaden our base of knowledge. MATERIALS AND METHODS: Four children with confirmed Keutel syndrome were reviewed for the brain, head and neck imaging findings. RESULTS: Three of the four children, all siblings, showed evidence of moyamoya syndrome. All four siblings had pinna cartilage calcification. CONCLUSION: We propose that Keutel syndrome be considered and included among the secondary causes of moyamoya syndrome. In children with petrified auricle and neurological symptoms, Keutel syndrome should be considered and brain MRI with MRA is required.

Superior rectal artery origin from the median sacral artery--angiographic appearance, developmental anatomy, and clinical implications.

Two angiographic observations of significant rectal vascularization by branches originating from the median sacral artery (MSA) are reported. In the first case, the MSA provided a complete superior rectal trunk, with left and right branches, while in the second, the MSA only contributed superior rectal branches to the right side of the rectum, the left side being supplied by left internal iliac branches. The angiographic appearance, developmental anatomy, and clinical significance of these variants are discussed.

Cochlear Aqueduct Morphology in Superior Canal Dehiscence Syndrome.

The cochlear aqueduct (CA) connects the scala tympani to the subarachnoid space and is thought to assist in pressure regulation of perilymph in normal ears, however, its role and variation in inner ear pathology, such as in superior canal dehiscence syndrome (SCDS), is unknown. This retrospective radiographic investigation compared CA measurements and classification, as measured on flat-panel computerized tomography, among three groups of ears: controls, n = 64; anatomic superior canal dehiscence without symptoms (SCD), n = 28; and SCDS, n = 64. We found that in a multinomial logistic regression adjusted for age, sex, and BMI, an increase in CA length by 1 mm was associated with a lower odds for being in the SCDS group vs. control (Odds ratio 0.760 p = 0.005). Hierarchical clustering of continuous CA measures revealed a cluster with small CAs and a cluster with large CAs. Another multinomial logistic regression adjusted for the aforementioned clinical covariates showed an odds ratio of 2.97 for SCDS in the small CA cluster as compared to the large (p = 0.004). Further, no significant association was observed between SCDS symptomatology-vestibular and/or auditory symptoms-and CA structure in SCDS ears. The findings of this study lend support to the hypothesis that SCDS has a congenital etiology.

Perioperative Management of Pediatric Patients with Moyamoya Arteriopathy.

Pediatric patients with moyamoya arteriopathy are at high risk for developing new onset transient or permanent neurologic deficits secondary to cerebral hypoperfusion, particularly in the perioperative period. It is therefore essential to carefully manage these patients in a multidisciplinary, coordinated effort to reduce the risk of new permanent neurologic deficits. However, little has been published on perioperative management of pediatric patients with moyamoya, particularly in the early postoperative period during intensive care unit admission. Our pediatric neurocritical care team sought to create a multidisciplinary periprocedural evidence- and consensus-based care pathway for high-risk pediatric patients with moyamoya arteriopathy undergoing anesthesia for any reason to decrease the incidence of periprocedural stroke or transient ischemic attack (TIA). We reviewed the literature to identify risk factors associated with perioperative stroke or TIA among patients with moyamoya and to gather data supporting specific perioperative management strategies. A multidisciplinary team from pediatric anesthesia, neurocritical care, nursing, child life, neurosurgery, interventional neuroradiology, neurology, and hematology created a care pathway for children with moyamoya undergoing anesthesia, classifying them as either high or standard risk, and applying an individualized perioperative management plan to high-risk patients. The incidence of neurologic sequelae before and after pathway implementation will be compared in future studies.

Childhood Brain Tumors: A Review of Strategies to Translate CNS Drug Delivery to Clinical Trials.

Brain and spinal tumors affect 1 in 1000 people by 25 years of age, and have diverse histological, biological, anatomical and dissemination characteristics. A mortality of 30-40% means the majority are cured, although two-thirds have life-long disability, linked to accumulated brain injury that is acquired prior to diagnosis, and after surgery or chemo-radiotherapy. Only four drugs have been licensed globally for brain tumors in 40 years and only one for children. Most new cancer drugs in clinical trials do not cross the blood-brain barrier (BBB). Techniques to enhance brain tumor drug delivery are explored in this review, and cover those that augment penetration of the BBB, and those that bypass the BBB. Developing appropriate delivery techniques could improve patient outcomes by ensuring efficacious drug exposure to tumors (including those that are drug-resistant), reducing systemic toxicities and targeting leptomeningeal metastases. Together, this drug delivery strategy seeks to enhance the efficacy of new drugs and enable re-evaluation of existing drugs that might have previously failed because of inadequate delivery. A literature review of repurposed drugs is reported, and a range of preclinical brain tumor models available for translational development are explored.

Preoperative embolization of primary spinal aneurysmal bone cysts by direct percutaneous intralesional injection of n-butyl-2-cyanoacrylate.

Aneurysmal bone cysts (ABCs) are highly vascular lesions often referred for preoperative transarterial embolization. However, accessible arterial pedicles do not always exist. Two cases are presented of pediatric patients with spinal ABCs in which preoperative embolization was performed by percutaneous injection of up to 31 mL of liquid embolic agent (1:7 ratio, n-butyl-2-cyanoacrylate [n-BCA] to ethiodized oil). Total estimated surgical blood loss was 1,000 mL in one case and 3,650 mL in the other case, which occurred during the extensive anterior and posterior approaches required to remove the massive ABCs. Direct percutaneous injection of n-BCA is a technically simple and efficient adjunct to surgical resection with the aim to reduce intraoperative blood loss.

2D Measurements of the Angle of the Vestibular Aqueduct Using CT Imaging.

Recently, Bächinger et al. developed a software that measures the angle between the vestibular aqueduct proximal to the vestibule and the distal vestibular aqueduct on computed tomography (CT) scans and found differences in the vestibular aqueduct angle between the hypoplastic and degenerative categories of Meniere's disease (MD). Hypoplastic radiological findings were associated with the development of bilateral MD and hypoplastic changes were not found outside of fetal temporal bones and individuals with MD. The purpose of this study is to examine how the software developed by Bächinger et al. performs when applied to a large dataset of adult patients with varied otologic diagnoses. Adult patients who underwent high resolution flat panel CT scans without intravenous contrast (n = 301) were retrospectively reviewed. Measurements of the angle of the vestibular aqueduct were made using the previously developed software tool. The tool could be applied to measure the vestibular aqueduct angle in most CT scans of the temporal bones (n = 572 ears, 95%). While the majority of ears fell within the normal range of <120 degrees (n = 462, 80%), fourteen ears (2.3%) in 13 patients were found to have vestibular aqueduct angles that meet criteria for hypoplastic MD (>140 degrees). Only one of the 13 patients had a diagnosis of MD and not in the ear in the hypoplastic category. An inconsistent pattern of other otologic diagnoses were found among the 13 individuals meeting criteria for hypoplastic MD. Although prior reports indicate the software has prognostic value in individuals with MD, these results suggest that the software may have lower positive predictive value when applied to a large population of individuals with varied otologic diagnoses.