Evolving indications for pediatric neurointerventional radiology: A single institutional 25-year experience in infants less than one year of age and a brief historical review.

BACKGROUND AND PURPOSE: Pediatric neurointerventional radiology is an evolving subspecialty with growing indications and technological advancement such as miniaturization of devices and decreased radiation dose. The ability to perform these procedures is continuously balanced with necessity given the inherently higher risks of radiation and cerebrovascular injury in infants. The purpose of this study is to review our institution's neurointerventional experience in infants less than one year of age to elucidate trends in this patient population. METHODS: We retrospectively identified 132 patients from a neurointerventional database spanning 25 years (1997-2022) who underwent 226 procedures. Treatment type, indication, and location as well as patient demographics were extracted from the medical record. RESULTS: Neurointerventional procedures were performed as early as day of life 0 in a patient with an arteriovenous shunting malformation. Average age of intervention in the first year of life is 5.9 months. Thirty-eight of 226 procedures were completed in neonates. Intra-arterial chemotherapy (IAC) for the treatment of retinoblastoma comprised 36% of neurointerventional procedures completed in infants less than one year of age followed by low flow vascular malformations (21.2%), vein of Galen malformations (11.5%), and dural arteriovenous fistulas (AVF) (9.3%). Less frequent indications include non-Galenic pial AVF (4.4%) and tumor embolization (3.0%). The total number of interventions has increased secondary to the onset of retinoblastoma treatment in 2010 at our institution. CONCLUSION: The introduction of IAC for the treatment of retinoblastoma in the last decade is the primary driver for the increased trend in neurointerventional procedures completed in infants from 1997 to 2022.

The Hybrid Operative Suite with Intraoperative Biplane Rotational Angiography in Pediatric Cerebrovascular Neurosurgery: Utility and Lessons Learned.

INTRODUCTION: The benefits of performing open and endovascular procedures in a hybrid neuroangiography surgical suite include confirmation of treatment results and reduction in number of procedures, leading to improved efficiency of care. Combined procedural suites are infrequently used in pediatric facilities due to technical and logistical limitations. We report the safety, utility, and lessons learned from a single-institution experience using a hybrid suite equipped with biplane rotational digital subtraction angiography and pan-surgical capabilities. METHODS: We conducted a retrospective review of consecutive cases performed at our institution that utilized the hybrid neuroangiography surgical suite from February 2020 to August 2021. Demographics, surgical metrics, and imaging results were collected from the electronic medical record. Outcomes, interventions, and nuances for optimizing preoperative/intraoperative setup and postoperative care were presented. RESULTS: Eighteen procedures were performed in 17 patients (mean age 13.4 years, range 6-19). Cases included 14 arteriovenous malformations (AVM; 85.7% ruptured), one dural arteriovenous fistula, one mycotic aneurysm, and one hemangioblastoma. The average operative time was 416 min (range 321-745). There were no intraoperative or postoperative complications. All patients were alive at follow-up (range 0.1-14.7 months). Five patients had anticipated postoperative deficits arising from their hemorrhage, and 12 returned to baseline neurological status. Four illustrative cases demonstrating specific, unique applications of the hybrid angiography suite are presented. CONCLUSION: The hybrid neuroangiography surgical suite is a safe option for pediatric cerebrovascular pathologies requiring combined surgical and endovascular intervention. Hybrid cases can be completed within the same anesthesia session and reduce the need for return to the operating room for resection or surveillance angiography. High-quality intraoperative angiography enables diagnostic confirmation under a single procedure, mitigating risk of morbidity and accelerating recovery. Effective multidisciplinary planning enables preoperative angiograms to be completed to inform the operative plan immediately prior to definitive resection.

Transradial Approach for Thoracolumbar Spinal Angiography and Tumor Embolization: Feasibility and Technical Considerations.

The transradial approach (TRA) is an effective and safe alternative to transfemoral access for diagnostic neuroangiography and craniocervical interventions. While the technical aspects of supraclavicular intervention are well-described, there are little data on the TRA for thoracolumbar angiography and intervention. The authors describe the feasibility of the TRA for preoperative thoracic tumor embolization, emphasizing technique, device selection, navigation, and catheterization of thoracolumbar segmental arteries. This approach extends the benefits of TRA to spinal interventional neuroradiology.

Endovascular treatment strategy, technique, and outcomes for dural arteriovenous fistulas of the marginal sinus region.

BACKGROUND: Dural arteriovenous fistulas (AVF) of the foramen magnum region (FMR) are technically challenging lesions to treat. Transvenous (TV), transarterial (TA), and surgical approaches have been described, but the optimum treatment strategy is not defined. OBJECTIVE: To report treatment strategies and outcomes for FMR-AVF at a single, high-volume referral center. METHODS: A retrospective review from January 2010 to August 2020 identified patients with FMR-AVF at a single referral center. Angiographic features, treatment (observation, endovascular, surgical), and follow-up of angiographic and clinical results were recorded. The technical aspects of TV embolization are then presented in detail. RESULTS: 29 FMR-AVF were identified in 28 patients. Of these, 24/29 (82.8%) were treated and 5/29 (17.2%) were observed. Treatment was endovascular in 21/24 (87.5%), combined (endovascular+surgical) in 2/24 (8.3%), and surgical in 1/24 (4.2%). Endovascular treatments were 76.2% TV, 14.3% TA, and 9.5% combined TV/TA. Sufficient follow-up data were available for 20/28 (71.4%) with mean follow-up of 16.8 months. No AVF recurrence was seen for TA/TV, combined endovascular/surgical, or surgical groups, and there was one recurrence (7.1%) in the TV group. Symptomatic improvement was seen in all groups: TV (71.4% complete, 28.6% partial), TA (66.7% complete, 33.3% no follow-up), TV+TA (100% partial), endovascular/surgical (100% complete), and surgical (100% partial). Minor non-neurologic complications included 1/14 (7.1%) in the TV group and 1/3 (33.3%) in the TA/TV group. CONCLUSION: Endovascular treatment is safe and effective for most FMR-AVF. TV embolization has a high cure rate with few complications.

Balloon-backstop technique: Preserving physiologic venous drainage during transvenous coil embolization of sigmoid sinus dural arteriovenous fistulas.

Dural arteriovenous fistulas can lead to catastrophic intracranial hemorrhage if left untreated. Transvenous embolization can cure arteriovenous fistulas, but preserving normal venous structures can be challenging. Inadvertent embolization of a functioning vein can result in catastrophic venous infarction or hemorrhage. Here, we report a case using balloon-assistance to facilitate preservation of the superior petrosal sinus during transvenous embolization of a sigmoid sinus dural arteriovenous fistula.

MRI and MR angiography evaluation of pulsatile tinnitus: A focused, physiology-based protocol.

BACKGROUND AND PURPOSE: Pulsatile tinnitus (PT) is the subjective sensation of a pulse-synchronous sound, most often due to a cerebrovascular etiology. PT can severely impact quality of life and may indicate a life-threatening process, yet a timely and accurate diagnosis can often lead to effective treatment. Clinical assessment with a history and physical examination can often suggest a diagnosis for PT, but is rarely definitive. Therefore, PT should be evaluated with a comprehensive and targeted radiographic imaging protocol. MR imaging provides a safe and effective means to evaluate PT. Specific MR sequences may be used to highlight different elements of cerebrovascular anatomy and physiology. However, routine MR evaluation of PT must comply with economic and practical constraints, while effectively capturing both common and rarer, life-threatening etiologies of PT. METHODS: In this state-of-the-art review, we describe our institutional MR protocol for evaluating PT. RESULTS: This protocol includes the following dedicated sequences: time-of-flight magnetic resonance angiography; arterial spin labeling; spoiled gradient recalled acquisition in the steady state; time-resolved imaging of contrast kinetics; diffusion weighted imaging, and 3-dimensional fluid-attenuated inversion recovery. CONCLUSIONS: We describe the physiologic and clinical rationale for including each MR sequence in a comprehensive PT imaging protocol, and detail the role of MR within the broader evaluation of PT, from clinical presentation to treatment.

Transitional vascular anomaly of a persistent medial procephalic vein causing obstructive hydrocephalus and intracranial haemorrhage.

We report a case of obstructive hydrocephalus caused by a transitional (shunting) developmental venous anomaly not previously reported in the literature. Both thalami in this patient drain into a midline vein in the floor of the third ventricle that crosses the cerebral aqueduct and exerts mass effect. While this patient's hydrocephalus was managed by a ventriculoperitoneal shunt catheter, their hospital course was complicated by a spontaneous intraparenchymal bleed of the left thalamus thought to be caused by their vascular malformation. Given the risk of venous infarcts, this transitional venous anomaly could not be treated safely.

The Composite Severity Score for Lumbar Spine MRI: a Metric of Cumulative Degenerative Disease Predicts Time Spent on Interpretation and Reporting.

Conventional measures of radiologist efficiency, such as the relative value unit, fail to account for variations in the complexity and difficulty of a given study. For lumbar spine MRI (LMRI), an ideal performance metric should account for the global severity of lumbar degenerative disease (LSDD) which may influence reporting time (RT), thereby affecting clinical productivity. This study aims to derive a global LSDD metric and estimate its effect on RT. A 10-year archive of LMRI reports comprising 13,388 exams was reviewed. Objective reporting timestamps were used to calculate RT. A natural language processing (NLP) tool was used to extract radiologist-assigned stenosis severity using a 6-point scale (0 = "normal" to 5 = "severe") at each lumbar level. The composite severity score (CSS) was calculated as the sum of each of 18 stenosis grades. The predictive values of CSS, sex, age, radiologist identity, and referring service on RT were examined with multiple regression models. The NLP tool accurately classified LSDD in 94.8% of cases in a validation set. The CSS increased with patient age and differed between men and women. In a univariable model, CSS was a significant predictor of mean RT (R2 = 0.38, p < 0.001) and independent predictor of mean RT (p < 0.001) controlling for patient sex, patient age, service location, and interpreting radiologist. The predictive strength of CSS was stronger for the low CSS range (CSS = 0-25, R2 = 0.83, p < 0.001) compared to higher CSS values (CSS > 25, R2 = 0.15, p = 0.05). Individual radiologist study volume was negatively correlated with mean RT (Pearson's R = - 0.35, p < 0.001). The composite severity score predicts radiologist reporting efficiency in LMRI, providing a quantitative measure of case complexity which may be useful for workflow planning and performance evaluation.

Effects of age and sex on the distribution and symmetry of lumbar spinal and neural foraminal stenosis: a natural language processing analysis of 43,255 lumbar MRI reports.

PURPOSE: The purpose of this study is to investigate relationship of patient age and sex to patterns of degenerative spinal stenosis on lumbar MRI (LMRI), rated as moderate or greater by a spine radiologist, using natural language processing (NLP) tools. METHODS: In this retrospective, IRB-approved study, LMRI reports acquired from 2007 to 2017 at a single institution were parsed with a rules-based natural language processing (NLP) algorithm for free-text descriptors of spinal canal stenosis (SCS) and neural foraminal stenosis (NFS) at each of six spinal levels (T12-S1) and categorized according to a 6-point grading scale. Demographic differences in the anatomic distribution of moderate (grade 3) or greater SCS and NFS were calculated by sex, and age and within-group differences for NFS symmetry (left vs. right) were calculated as odds ratios. RESULTS: Forty-three thousand two hundred fifty-five LMRI reports (34,947 unique patients, mean age = 54.7; sex = 54.9% women) interpreted by 152 radiologists were studied. Prevalence of significant SCS and NFS increased caudally from T12-L1 to L4-5 though less at L5-S1. NFS was asymmetrically more prevalent on the left at L2-L3 and L5-S1 (p < 0.001). SCS and NFS were more prevalent in men and SCS increased with age at all levels, but the effect size of age was largest at T12-L3. Younger patients (< 50 years) had relatively higher NFS prevalence at L5-S1. CONCLUSION: NLP can identify patterns of lumbar spine degeneration through analysis of a large corpus of radiologist interpretations. Demographic differences in stenosis prevalence shed light on the natural history and pathogenesis of LSDD.

Optic Neuropathy Due to Compression by an Ectatic Internal Carotid Artery Within the Orbital Apex.

ABSTRACT: Neurovascular compression is a rare but potentially treatable cause of optic neuropathy. Although incidental contact of the cisternal optic nerve and internal carotid artery (ICA) is common, compressive optic neuropathy occurring within the orbital apex has not been comprehensively described. We report a case of intra-orbital and intracanalicular optic nerve compression due to an ectatic ICA in a patient with congenital absence of the contralateral ICA. This report describes the complementary roles of advanced neuroimaging and neuro-ophthalmologic examination in rendering the diagnosis.

The Effect of Extracranial-to-Intracranial Bypass on Cerebral Vasoreactivity: A 4D Flow MRI Pilot Study.

BACKGROUND AND PURPOSE: Extracranial-to-intracranial (EC-IC) surgical bypass improves cerebral blood flow (CBF) and cerebrovascular vasoreactivity (CVR) for patients with carotid occlusion. Bypass graft patency and contribution of the graft to the postoperative increase in CVR are challenging to assess. To assess the effectiveness of 4D flow magnetic resonance imaging (MRI) to evaluate bypass graft patency and flow augmentation through the superficial temporal artery (STA) before and after EC-IC bypass. METHODS: Three consecutive patients undergoing EC-IC bypass for carotid occlusion were evaluated pre- and postoperatively using CVR testing with pre- and poststimulus 4D flow-MRI for assessment of the bypass graft and intracranial vasculature. RESULTS: Preoperatively, 2 patients (patients 1 and 3) did not augment flow through either native STA. The third, who had evidence of extensive native EC-IC collateralization on digital subtraction angiography (DSA), did augment flow through the STA preoperatively (CVR = 1). Postoperatively, all patients demonstrated CVR > 1 on the side of bypass. The patient who had CVR > 1 preoperatively demonstrated the greatest increase in resting postoperative graft flow (from 40 to 130 mL/minute), but the smallest CVR, with a poststimulus graft flow of 160 mL/minute (CVR = 1.2). The 2 patients who did not demonstrate augmentation of graft flow preoperatively augmented postoperatively from 10 to 20 mL/minute (CVR = 2.0) and 10-80 mL/minute (CVR = 8.0), respectively. Intracranial flow was simultaneously interrogated. Two patients demonstrated mild reductions in resting flow velocities in all interrogated vessels immediately following bypass. The patient who underwent CVR testing on postoperative day 48 demonstrated a stable or increased flow rate in most intracranial vessels. CONCLUSION: Four-dimensional flow MRI allows for noninvasive, simultaneous interrogation of the intra- and extracranial arterial vasculature during CVR testing, and reveals unique paradigms in cerebrovascular physiology. Observing these flow patterns may aid in improved patient selection and more detailed postoperative evaluation for patients undergoing EC-IC bypass.

The role of nicotinic cholinergic neurotransmission in delusional thinking.

Delusions are a difficult-to-treat and intellectually fascinating aspect of many psychiatric illnesses. Although scientific progress on this complex topic has been challenging, some recent advances focus on dysfunction in neural circuits, specifically in those involving dopaminergic and glutamatergic neurotransmission. Here we review the role of cholinergic neurotransmission in delusions, with a focus on nicotinic receptors, which are known to play a part in some illnesses where these symptoms appear, including delirium, schizophrenia spectrum disorders, bipolar disorder, Parkinson, Huntington, and Alzheimer diseases. Beginning with what we know about the emergence of delusions in these illnesses, we advance a hypothesis of cholinergic disturbance in the dorsal striatum where nicotinic receptors are operative. Striosomes are proposed to play a central role in the formation of delusions. This hypothesis is consistent with our current knowledge about the mechanism of action of cholinergic drugs and with our abstract models of basic cognitive mechanisms at the molecular and circuit levels. We conclude by pointing out the need for further research both at the clinical and translational levels.

Colonic Wall Thickening as the First Indicator of Relapse of Acute Lymphoblastic Leukemia.

The gastrointestinal (GI) tract is a rarely reported site of extramedullary relapse of acute lymphoblastic leukemia (ALL). We report a patient being effectively treated with immunotherapy for relapsed ALL who was incidentally noted to have colonic wall thickening on imaging that was subsequently pathologically confirmed to be the result of disease infiltration of colonic tissue. Primary ALL involvement of the GI tract should be considered in the evaluation of GI complaints in patients with ALL, particularly those with relapsed disease otherwise effectively treated with immunotherapy.

Cryptogenic Multifocal Ulcerative Sclerosing Enteritis: A Curious Case of Intestinal Obstruction in the Setting of Human Immunodeficiency Virus.

Cryptogenic multifocal ulcerative sclerosing enteritis (CMUSE) is a rare clinical entity characterized by chronic, relapsing episodes of ileus and obstruction resulting from superficial ulcerating lesions of the small intestine with a clinical course that responds favorably to corticosteroids. We report a case of CMUSE arising in a patient with a history of human immunodeficiency virus infection. This case highlights the unique pathology of CMUSE as well as the potential pathogenesis of this atypical clinical entity.

Non-traumatic subdural hemorrhage: beware of ruptured intracranial aneurysm.

Acute subdural hemorrhage (SDH) is commonly encountered by emergency radiologists in the setting of trauma. When history or imaging evidence of trauma is absent, the differential diagnosis for SDH should be expanded. Intracranial aneurysm rupture is a rare and underrecognized cause of SDH which may present without concurrent subarachnoid hemorrhage. The mechanism of aneurysmal SDH is controversial, but understanding the anatomic microenvironment of the aneurysm provides insight and clarifies aneurysm features predisposing to subdural compartment rupture. Aneurysmal SDH is a neurosurgical emergency and its treatment strategies differ from traumatic SDH. Outcomes are poor if treatment is delayed; thus, radiologists play a central role in recognizing this uncommon but potentially devastating complication of aneurysm rupture. The goal of this article is to familiarize radiologists with clinical and imaging characteristics of aneurysmal SDH and review pertinent anatomy, risk factors, and potential etiologies. Aneurysmal rupture can easily be overlooked in the routine workup of atraumatic SDH, and radiologists must know when to recommend vascular imaging to avoid the catastrophic consequences of a missed diagnosis.

18F-FDG Uptake in Subcutaneous Fat Preceding Clinical Diagnosis of Human Immunodeficiency Virus-Associated Lipodystrophy.

A 62-year-old man with human immunodeficiency virus (HIV) on long-standing highly active antiretroviral therapy presented for F-FDG PET/CT evaluation of a pulmonary nodule. The examination showed unusual radiotracer distribution accumulating in the subcutaneous and visceral fat with low cerebral and skeletal muscle uptake. Imaging features were consistent with HIV-associated lipodystrophy, an unsuspected diagnosis that was later confirmed on physical examination. Recognition of HIV-associated lipodystrophy by the nuclear medicine physician is critical as altered biodistribution may affect diagnostic yield or be mistaken for infectious pathology.

Estimating glutamate and Glx from GABA-optimized MEGA-PRESS: Off-resonance but not difference spectra values correspond to PRESS values.

Proton magnetic resonance spectroscopy measurements of glutamate and GABA are important in neuropsychiatric research. Some study designs require simultaneous measurement of both metabolites. GABA measurement requires specialized pulse sequences, the most common approach being J-difference spectral editing with MEGA-PRESS. This method enables two different strategies for concurrently measuring glutamate - from either off-resonance or difference spectra. However, it is uncertain how either strategy compares to conventional glutamate measurements. Here we compared these approaches in 49 subjects (28 healthy volunteers and 21 first-episode psychosis patients), in whom both PRESS (TE 80) and MEGA-PRESS (TE 68) spectra were obtained from dorsolateral prefrontal cortex. Glutamate and glx estimates from MEGA-PRESS difference and off-resonance spectra were compared to glutamate and glx estimates from PRESS spectra using correlational analyses. In healthy volunteers, correlations between PRESS and MEGA-PRESS off-resonance values were r ≥ 0.88 and were significantly higher than correlations between PRESS and MEGA-PRESS difference spectrum values (r ≤ 0.36). Patients showed a similar pattern. Lower correlations with difference spectrum values may reflect a disproportionate impact of field instabilities on co-edited glutamate signals. The results suggest that MEGA-PRESS off-resonance spectra can substitute for separately-acquired PRESS spectra in studies requiring simultaneous glutamate and GABA measurements.