Expect the unexpected: a case of spontaneous thrombosis of a pial arteriovenous fistula in a preterm newborn with review of the literature.

INTRODUCTION: Pial arteriovenous fistulas (pAVF) are rare vascular malformations, especially in children and newborns. In neonates, the most common symptom is congestive heart failure. CASE PRESENTATION: We report a case of an asymptomatic preterm newborn incidentally diagnosed with pAVF during a routine cranial ultrasound (cUS) on the third day of life. Cerebral magnetic resonance (MRI) confirmed the diagnosis. A wait-and-see approach was chosen by the multidisciplinary team. The cUS and the MRI on day 14 of life showed the spontaneous resolution of the lesion. CONCLUSIONS: This case underlines the challenges in identifying pAVF in the first weeks of life and demonstrates a possible positive outcome for affected neonates.

Neonatal Subpial Hemorrhage: Clinical Factors, Neuroimaging, and Outcomes in a Quaternary Care Children's Center.

BACKGROUND: Subpial hemorrhages are underrecognized, underreported, and poorly understood. The spectrum of their clinical manifestations and consequences in neonates has not been fully described. Here, we describe the demographic, clinical, and radiographic characteristics of neonates with subpial hemorrhages. METHODS: We reviewed the medical records and neuroimaging studies of neonates with subpial hemorrhage who were admitted to our neonatal intensive care unit between September 2009 and December 2020. RESULTS: Of 114 neonates with intracranial hemorrhage, 31 (27%) had subpial hemorrhage. The majority of neonates in our cohort were male (68%) and born at term (55%). The most common imaging indication was apneas and/or seizures in 58%. Common comorbid conditions included cardiorespiratory failure (42%), hypoxic-ischemic encephalopathy (26%), and coagulopathy (23%). Subpial hemorrhages were multifocal in 45% of neonates, located in the temporal lobe in 45% of neonates, and tended to be larger in neonates with coagulopathy, birth trauma, or hydrocephalus requiring neurosurgical intervention. Subpial hemorrhage was associated with another type of intracranial bleed in 77% of cases and with arterial ischemic stroke in 16% of cases. Of 17 patients with more than one year of follow-up data, 14 (82%) have developmental delay and four (24%) have epilepsy. Of 14 patients with follow-up imaging, 10 (71%) had encephalomalacia subjacent to the subpial hemorrhage. CONCLUSIONS: This is the largest cohort of neonates with subpial hemorrhages to date. Outcome data are limited by duration of follow-up and may be confounded by comorbid conditions and other concurrent hemorrhages. Further study is needed to define the spectrum of risk factors and expected neurological outcomes.

Subpial Hemorrhage in Neonates: What Radiologists Need to Know.

OBJECTIVE. Subpial hemorrhages, typically seen in neonates, are rare but can harm the adjacent brain parenchyma. The purpose of this review is to summarize the anatomy and pathophysiology of subpial hemorrhage and highlight its characteristic neuro-imaging pattern. CONCLUSION. The distinctive neuroimaging pattern of subpial hemorrhage is best appreciated on brain MRI, which shows the morphology over the cortex and injury to adjacent cortex and subcortical white matter. These findings do not occur in subarachnoid and subdural hemorrhages. Recognizing the pattern of subpial hemorrhages should guide prognostic precision, prognostication, and counseling.

Pial arteriovenous fistula with appearance of hemorrhagic tumor: A case report.

INTRODUCTION: Pial arteriovenous fistula (PAVF) is a rare intracranial vascular disease, and its presentation with a huge tumor-resembling thrombus is rarer. PATIENT CONCERNS: A 38-year-old female patient presented with a sudden left-side motor disorder and loss of consciousness. The patient was otherwise in good health and had no history of hypertension or diabetes. During the physical examination, she appeared lethargic and manifested left limb paralysis with level zero muscle strength and a positive pathological reflex. DIAGNOSES: Because imaging failed to rule out a tumor stroke, an intracranial lesion resection was performed immediately. Because the lesion was considered to be a vascular structure, digital subtraction angiography was undertaken before the surgery, and PAVF was diagnosed. INTERVENTIONS: Endovascular embolization was conducted, followed by PAVF and hematoma resection. OUTCOMES: At the 3-month follow up, her left limb muscle strength was level 4, and she could live on her own (Modified Rankin Scale score = 2). CONCLUSIONS: It is noteworthy that PAVF with a large thrombus may appear as a tumor in the initial diagnosis, and therefore it is necessary to perform an intracranial vascular examination in patients with tumor stroke symptoms.

Multiple Cranial Dural and Pial Arteriovenous Fistulas with Occlusion of All After Embolization of Primary Superior Sagittal Sinus Dural Fistula.

BACKGROUND: We present a rare case of multiple intracranial arteriovenous fistulas (AVFs). A young female presented with headache and a left eyelid pulsatile swelling. CASE DESCRIPTION: Magnetic resonance imaging demonstrated numerous dilated cortical veins, along with a prominent left superior ophthalmic vein. A diagnostic cerebral angiogram revealed 5 distinct AVFs including 4 dural AVFs (dAVFs) and a pial AVF (pAVF). The largest dAVF was at the superior sagittal sinus. The others included bilateral ethmoidal, torcular, and a pAVF arising of the right pericallosal artery. She was treated by endovascular transarterial Onyx embolization. Only the superior sagittal sinus fistula was treated via middle meningeal artery feeders with complete occlusion. Immediate follow-up angiogram also showed complete spontaneous occlusion of the untreated dAVFs and pial AVF. CONCLUSIONS: This case is exceedingly unique considering the multiplicity of AVFs, concurrent presence of pial and dural AVF, and spontaneous occlusion of all untreated AVFs after embolizing the largest shunting fistula.

Pediatric pial arteriovenous fistula located at the bottom of the callosal sulcus presenting with intraventricular hemorrhage: a case report and literature review.

BACKGROUND: A pial arteriovenous fistula (pAVF) is a rare condition characterized by a direct connection between a cerebral artery and cerebral vein without an intervening nidus. The prognosis is poor in untreated cases with hemorrhagic manifestations, indicating that surgical treatment is desirable. We describe a successful endovascular treatment for a pediatric case of ruptured pAVF located at the bottom of the sulcus. CLINICAL DESCRIPTION: An 11-year-old girl presented with severe headache and mild disturbance of consciousness. Head computed tomography showed hemorrhage in the callosal sulcus and ventricle. Cerebral angiography showed an arteriovenous shunt without a nidus. The branching artery from the pericallosal artery was connected directly to the thalamostriate vein without varix, and the shunt point was located at the bottom of the callosal sulcus. The patient was diagnosed with pAVF involving a single feeder and single drainer. Emergency endovascular transarterial embolization was performed using 20% N-butyl cyanoacrylate, and the shunt disappeared completely without complications. The patient was discharged with no neurological deficits. CONCLUSION: Endovascular treatment is feasible, safe, and effective for pediatric cases of deeply located pAVF.

Spatial distribution of human arachnoid trabeculae.

Traumatic brain injury (TBI) is a common injury modality affecting a diverse patient population. Axonal injury occurs when the brain experiences excessive deformation as a result of head impact. Previous studies have shown that the arachnoid trabeculae (AT) in the subarachnoid space significantly influence the magnitude and distribution of brain deformation during impact. However, the quantity and spatial distribution of cranial AT in humans is unknown. Quantification of these microstructural features will improve understanding of force transfer during TBI, and may be a valuable dataset for microneurosurgical procedures. In this study, we quantify the spatial distribution of cranial AT in seven post-mortem human subjects. Optical coherence tomography (OCT) was used to conduct in situ imaging of AT microstructure across the surface of the human brain. OCT images were segmented to quantify the relative amounts of trabecular structures through a volume fraction (VF) measurement. The average VF for each brain ranged from 22.0% to 29.2%. Across all brains, there was a positive spatial correlation, with VF significantly greater by 12% near the superior aspect of the brain (p < .005), and significantly greater by 5%-10% in the frontal lobes (p < .005). These findings suggest that the distribution of AT between the brain and skull is heterogeneous, region-dependent, and likely contributes to brain deformation patterns. This study is the first to image and quantify human AT across the cerebrum and identify region-dependencies. Incorporation of this spatial heterogeneity may improve the accuracy of computational models of human TBI and enhance understanding of brain dynamics.

Trigeminal neuralgia associated with cerebellar pial arteriovenous fistula: A case report.

RATIONALE: Trigeminal neuralgia (TN) is frequently associated with compression at the root entry zone of the trigeminal nerve by an aberrant loop of an artery, tributaries of the petrosal vein, tumors, aneurysm, and vascular malformation. TN associated with a cerebellar pial arteriovenous fistula (PAVF) has not been described previously. PATIENT CONCERNS: A 65-year-old man presented with right-sided TN. Cerebral angiography revealed a right cerebellar PAVF and magnetic resonance imaging demonstrated a mixed compression of the petrous vein complex and anterior inferior cerebellar artery at the right trigeminal nerve. DIAGNOSIS: Due to the patient's symptoms, radiographic findings, he was diagnosed with TN and PAVF. INTERVENTIONS: Coiling combined with use of the liquid embolic agent Onyx was used for the complete embolization of the fistula. OUTCOMES: Complete relief of the pain was achieved 3 months after endovascular treatment, and the patient has remained pain-free during 2 years of follow-up. CONCLUSIONS: Endovascular treatment with a combination of coils and Onyx embolization is an effective approach for complete resolution of rarely occurring TN caused by mixed venous and arterial compressions associated with cerebellar PAVF.

How to differentiate spinal cord hemangiopericytoma from common spinal cord tumor?

INTRODUCTION: Tumors of the spinal cord are rare and some can be confused with each other. We report a rare spinal cord solitary fibrous tumor/hemangiopericytoma (SFT/HPC), and propose keys to differentiate spinal cord tumors from each other. CASE REPORT: A 67-year-old man presented weakness with recent diffuse sensory disorders in the right lower limb. Spinal MRI revealed a T8-T9 intradural extramedullary mass with spinal cord compression. Gross total resection of a poorly vascularized intradural tumor was achieved. It was an encapsulated extramedullary tumor, which was difficult to separate from the spinal cord due to the presence of pial adhesions. Definitive diagnosis was grade 1 SFT/HPC of the spinal cord. One-year follow-up MRI revealed complete excision without any evidence of residual tumor. CONCLUSION: SFT/HPC is a very rare spinal tumor that can be extramedullary, intramedullary or both. It may perfectly mimic meningioma. The maximal resection is the best treatment, but can be challenging because of the tumor's firm consistency and pial adherences to the spinal cord. Outcome is good in case of gross total resection, but there is a risk of very late recurrence, requiring long-term follow-up.

Predictors for the extent of pial collateral recruitment in acute ischemic stroke.

BACKGROUND: Pial arterioles can provide a variable degree of collateral flow to ischemic vascular territories during acute ischemic stroke. This study sought to identify predictive factors of the degree of pial collateral recruitment in acute ischemic stroke. METHODS: Clinical information and arteriograms from 62 consecutive patients with stroke due to either middle cerebral artery (MCA) M1 segment or internal carotid artery (ICA) terminus occlusion within 6 h following symptom onset were retrospectively reviewed. Pial collaterals were defined based on the extent of reconstitution of the MCA territory. Patients with slow antegrade flow distal to the occlusion site were excluded and no anesthetics were used prior or during angiography. Results were analyzed using multivariate nominal logistic regression. RESULTS: Better pial collateral recruitment was associated with proximal MCA versus ICA terminus occlusion (p = 0.005; odds ratio (OR) = 9.3; 95% confidence interval (CI), 2.16-53.3), lower presenting National Institutes of Health Stroke Scale Score (NIHSSS) (p = 0.023; OR = 6.51; 95% CI, 1.49-41.7), and lower diastolic blood pressure (p = 0.0411; OR = 5.05; 95% CI, 1.20-29.2). Age, gender, symptom duration, diabetes, laterality, systolic blood pressure, glucose level, hematocrit, platelet level, and white blood cell count at presentation were not found to have a statistically significant association with pial collateral recruitment. CONCLUSIONS: Extent of pial collateral recruitment is strongly associated with the occlusion site (MCA M1 segment versus ICA terminus) and less strongly associated with presenting NIHSSS and diastolic blood pressure.

Risks associated with oral deferiprone in the treatment of infratentorial superficial siderosis.

OBJECTIVE: Deferiprone is an iron chelator that has recently been used to treat patients with infratentorial superficial siderosis (iSS). It is considered to have a generally favourable safety profile but concerns have been raised due to the risk of agranulocytosis. We aimed to evaluate the safety and tolerability of oral deferiprone as a treatment for patients with iSS. METHODS: We present a case series of 10 consecutive patients presenting with classical iSS treated with deferiprone. RESULTS: Ten patients were followed up for a mean period of 2.3 years (range 0.5-5.5 years). Four patients (40%) were withdrawn from treatment because of treatment-related side effects. The reasons for treatment discontinuation were neutropenic sepsis (n = 3) and fatigue (n = 1). In 2 out of the 3 cases of neutropenic sepsis, patients initially developed neutropenia without sepsis. The mean time to neutropenic sepsis following deferiprone was 1.2 years (range 0.3-2.5) with mean neutrophil count of 0.4 (range 0.3-0.5). Six patients (60%) reported no change in neurological function while on treatment, and four patients (40%) reported that their condition deteriorated. CONCLUSIONS: Deferiprone was poorly tolerated, with 40% of patients withdrawing from treatment, most commonly due to neutropenic sepsis, after an average of 2 years on treatment. This study increases the number of reported cases of agranulocytosis in patients with iSS treated with deferiprone. Clinicians treating iSS patients with deferiprone should be aware that this drug has a potentially life-threatening side effect of neutropenic sepsis, and should ensure that appropriate haematological monitoring is in place.

Micromechanical heterogeneity of the rat pia-arachnoid complex.

To better understand the onset of damage occurring in the brain upon traumatic events, it is essential to analyze how external mechanical loads propagate through the skull and meninges and down to the brain cortex. However, despite their crucial role as structural dampers protecting the brain, the mechanical properties and dynamic behavior of the meningeal layers are still poorly understood. Here, we characterized the local mechanical heterogeneity of rat pia-arachnoid complex (PAC) at the microscale via atomic force microscopy (AFM) indentation experiments to understand how microstructural variations at the tissue level can differentially affect load propagation. By coupling AFM mechanical testing with fresh tissue immunofluorescent staining, we could directly observe the effect of specific anatomical features on the local mechanical properties of tissue. We observed a two-fold stiffening of vascularized tissue when compared to non-vascularized PAC (with instantaneous Young's modulus distribution means of 1.32  ±â€¯ 0.03 kPa and 2.79  ±â€¯ 0.08 kPa, respectively), and statistically significant differences between regions of low- and high-vimentin density, reflecting trabecular density (with means of 0.67  ±â€¯ 0.05 kPa and 1.29  ±â€¯ 0.06 kPa, respectively). No significant differences were observed between cortical and cerebellar PAC. Additionally, by performing force relaxation experiments at the AFM, we identified the characteristic time constant τ1 of PAC tissue to be in the range of 2.7  ±â€¯ 1.2 s to 3.1  ±â€¯ 0.9 s for the different PAC regions analyzed. Taken together, the results presented point at the complex biomechanical nature of the meningeal tissue, and underscore the need to account for its heterogeneity when modeling its behavior into finite element simulations or other computational methods enabling the prediction of load propagation during injury events. STATEMENT OF SIGNIFICANCE: The meningeal layers are pivotal in shielding the brain during injury events, yet the mechanical properties of this complex biological interface are still under investigation. Here, we present the first anatomically-informed micromechanical characterization of mammalian pia-arachnoid complex (PAC). We developed a protocol for the isolation and fresh immunostaining of rat PAC and subjected the tissue to AFM indentation and relaxation experiments, while visualizing the local anatomy via fluorescence microscopy. We found statistically significant variations in regional PAC stiffness according to the degree of vascularization and trabecular cell density, besides identifying the tissue's characteristic relaxation constant. In essence, this study captures the relationship between anatomy and mechanical heterogeneity in a key component of the brain-skull interface for the first time.

Brain pharmacology of intrathecal antisense oligonucleotides revealed through multimodal imaging.

Intrathecal (IT) delivery and pharmacology of antisense oligonucleotides (ASOs) for the CNS have been successfully developed to treat spinal muscular atrophy. However, ASO pharmacokinetic (PK) and pharmacodynamic (PD) properties remain poorly understood in the IT compartment. We applied multimodal imaging techniques to elucidate the IT PK and PD of unlabeled, radioactively labeled, or fluorescently labeled ASOs targeting ubiquitously expressed or neuron-specific RNAs. Following lumbar IT bolus injection in rats, all ASOs spread rostrally along the neuraxis, adhered to meninges, and were partially cleared to peripheral lymph nodes and kidneys. Rapid association with the pia and arterial walls preceded passage of ASOs across the glia limitans, along arterial intramural basement membranes, and along white-matter axonal bundles. Several neuronal and glial cell types accumulated ASOs over time, with evidence of probable glial accumulation preceding neuronal uptake. IT doses of anti-GluR1 and anti-Gabra1 ASOs markedly reduced the mRNA and protein levels of their respective neurotransmitter receptor protein targets by 2 weeks and anti-Gabra1 ASOs also reduced binding of the GABAA receptor PET ligand 18F-flumazenil in the brain over 4 weeks. Our multimodal imaging approaches elucidate multiple transport routes underlying the CNS distribution, clearance, and efficacy of IT-dosed ASOs.

Dural Arteriovenous Fistulas at the Petrous Apex with Pial Arterial Supplies.

OBJECTIVE: Dural arteriovenous fistula (DAVF) at the petrous apex with pial arterial supplies possesses complicated angioarchitecture, associates with aggressive neurologic behaviors, and associates with high risk of complications. This study aimed to summarize our experience with this type of DAVF in the last 15 years. METHODS: This retrospective study reviewed 26 consecutive patients diagnosed with DAVFs of the petrous apex with pial arterial supplies from February 2002 to June 2017. Clinical information was extracted from medical records, radiographic data, intraoperative images, and complications and follow-up records. RESULTS: The 26 patients included 24 men and 2 women, with a mean age of 46.54 ± 12.49 years (range, 28-73 years). Manifestations included nonhemorrhagic neurologic defects (19/26, 73.1%), subarachnoid hemorrhage (SAH) (5/26, 19.2%), and no symptoms (2/26, 7.7%). Supratentorial draining direction was detected in 89.47% of the lesions, and 80% of the patients with venous ectasia had SAH. Complete occlusion was achieved in 21 patients (80.77%) through transarterial embolization and 5 patients (19.2%) through preoperative embolization combined with microsurgery. Complications included transient cranial nerve palsy in 1 patient (3.8%) and rebleeding in 2 patients (7.7%). The Barthel Index scores ranged from 10 to 100 (average, 66.73) and improved significantly (average, 96.62) in the follow-up period (10-175 months; median, 85.6 months). CONCLUSIONS: Supratentorial draining direction may be a risk factor for venous ectasia and SAH in petrous apex DAVFs with pial arterial supplies. The feeding pial arteries appeared to be at risk of embolization-related hemorrhagic complication and are therefore suggested to be embolized first.

Dural and Pial Arteriovenous Fistulas Connected to the Same Drainer in the Middle Cranial Fossa: A Case Report.

BACKGROUND: Dural arteriovenous fistulas (AVFs) in the middle cranial fossa are rare. Pial AVFs are similarly rare but differ from dural AVFs in that they derive their arterial supply from pial or cortical arterial vessels and do not lie within the intradural region. We report an extremely rare case of dural and pial AVF connected to the same drainer in the middle cranial fossa. CASE DESCRIPTION: In a 58-year-old man with a subcortical hemorrhage in the right temporal lobe, digital subtraction angiography showed a dural AVF in the middle cranial fossa fed by the middle meningeal artery (MMA) and draining into the sphenopetrosal vein. A combination with a small pial AVF connected to the same sphenopetrosal vein was suspected. Open surgery was performed to directly observe the shunt points. Transarterial indocyanine green (ICG) angiography using the MMA via the superficial temporal artery on a skin flap was performed to repeatedly and distinctly evaluate the dural shunt points and to prevent cerebral thromboembolism. Although the dural supply was completely disconnected, the sphenopetrosal vein remained arterialized. ICG angiography revealed pial AVF, which was fed by the cortical arteries draining into the same drainer. The pial supply was completely disconnected, and disappearance of the dural and pial AVF was confirmed. CONCLUSIONS: We report an extremely rare case of dural and pial AVF connected to the same drainer in the middle cranial fossa. To our knowledge, this is the first such case report described in the literature.

Neonatal Intracranial Pial Arteriovenous Fistula Treated with Endovascular Embolization: A Case Report.

BACKGROUND: Pial arteriovenous fistulas (PAVFs) are rare vascular malformations, especially in neonates. The purpose of this report is to discuss the treatment strategy and its associated challenges. We present a case of prenatal intracranial PAVF treated by endovascular embolization in the neonatal period. CASE DESCRIPTION: The patient was born through Cesarean delivery and then treated twice using transarterial embolization with detachable platinum coils and n-butyl cyanoacrylate due to intractable heart failure. Even though angiography findings showed dramatical reduction in the shunt, the patient did not recover from heart failure and died at day 49 after birth. CONCLUSIONS: Despite current developments in medical technology and therapies, the effective treatment of critical PAVFs still poses a challenge. Therefore, more indications and effective alternative treatments must be discussed.

Clipping of a Pediatric Pial Arteriovenous Fistula Located at Basilar Artery Tip Using a Hybrid Trapping-Evacuation Technique.

BACKGROUND: Intracranial pial arteriovenous fistulas (PAVFs) are rare cerebrovascular lesions with high mortality rates. We report a rare case of pediatric PAVF at the basilar artery tip and its treatment with surgical clipping aided by a trapping-evacuation technique in a hybrid operating room. CASE DESCRIPTION: An 18-month-old boy was admitted with hypoevolutism and 4-month history of weakness in the left extremities. Magnetic resonance imaging showed a giant aneurysm-like malformation in the area of midbrain and pons. Angiography showed a high-flow PAVF fed by the basilar artery and bilateral P1 segments of the posterior cerebral artery, with deep draining veins into the transverse sinus and straight sinus. Given the intrinsic characteristics of the lesion, such as deep location, giant fistula and varix, and multiple feeding arteries, clipping of PAVF was performed in a hybrid operating room aided by a trapping-evacuation technique to clearly identify and block the shunting point. CONCLUSIONS: The successful obliteration of the lesion is reported. In addition, a brief review of literature comparing endovascular embolization, surgical disconnection, and hybrid technique for treatment of PAVF is included.

Transarterial Balloon-Assisted Glue Embolization of Pial Arteriovenous Fistulas.

OBJECTIVE: Endovascular disconnection of pial arteriovenous fistulas (AVFs) is challenging. The aim of this study was to evaluate safety and effectiveness of transarterial balloon-assisted glue embolization for treating pial AVFs. METHODS: We retrospectively reviewed medical and imaging records of 8 patients with high-flow pial AVFs treated by transarterial balloon-assisted glue embolization from August 2011 to July 2017. RESULTS: There were 6 male patients and 2 female patients with age range of 1-48 years. Presentation was seizure in 4 patients, headache in 3 patients, and subarachnoid hemorrhage in 1 patient. Seven lesions were located in the supratentorial region. All lesions were single-channel fistulas associated with venous varix. Five lesions had a single feeder, and 3 had multiple feeders. All lesions were obliterated completely in single-session embolization with no procedure-related complications. Two patients experienced symptomatic thrombosis of drainage venous system after embolization. One patient fully recovered on discharge, and another patient fully recovered after 8 months. With a mean clinical follow-up of 12.1 months, all patients were free of pretreatment symptoms. Follow-up angiograms revealed durable occlusion of fistulas. CONCLUSIONS: Transarterial balloon-assisted glue embolization is a feasible and effective option for treatment of high-flow pial AVFs.