Pediatric Interventional Neuroradiology: "How I Do It" v. I - Diagnostic Angiography.

Pediatric neurointervention differs from the adult in several important respects. Here we describe a modern approach to readily acquire diagnostic quality images of children. Preparation, access, angiogragraphy and closure have evolved along with new knowledge and technology. This timely "how I do it" series addresses each topic utilizing literature review and our own experience over 35 years.

Background Subtraction Angiography with Deep Learning Using Multi-frame Spatiotemporal Angiographic Input.

Catheter Digital Subtraction Angiography (DSA) is markedly degraded by all voluntary, respiratory, or cardiac motion artifact that occurs during the exam acquisition. Prior efforts directed toward improving DSA images with machine learning have focused on extracting vessels from individual, isolated 2D angiographic frames. In this work, we introduce improved 2D + t deep learning models that leverage the rich temporal information in angiographic timeseries. A total of 516 cerebral angiograms were collected with 8784 individual series. We utilized feature-based computer vision algorithms to separate the database into "motionless" and "motion-degraded" subsets. Motion measured from the "motion degraded" category was then used to create a realistic, but synthetic, motion-augmented dataset suitable for training 2D U-Net, 3D U-Net, SegResNet, and UNETR models. Quantitative results on a hold-out test set demonstrate that the 3D U-Net outperforms competing 2D U-Net architectures, with substantially reduced motion artifacts when compared to DSA. In comparison to single-frame 2D U-Net, the 3D U-Net utilizing 16 input frames achieves a reduced RMSE (35.77 ± 15.02 vs 23.14 ± 9.56, p < 0.0001; mean ± std dev) and an improved Multi-Scale SSIM (0.86 ± 0.08 vs 0.93 ± 0.05, p < 0.0001). The 3D U-Net also performs favorably in comparison to alternative convolutional and transformer-based architectures (U-Net RMSE 23.20 ± 7.55 vs SegResNet 23.99 ± 7.81, p < 0.0001, and UNETR 25.42 ± 7.79, p < 0.0001, mean ± std dev). These results demonstrate that multi-frame temporal information can boost performance of motion-resistant Background Subtraction Deep Learning algorithms, and we have presented a neuroangiography domain-specific synthetic affine motion augmentation pipeline that can be utilized to generate suitable datasets for supervised training of 3D (2d + t) architectures.

Distal radial access for neuroangiography and neurointerventions: systematic review and meta-analysis.

BACKGROUND: Many studies have shown that coronary angiography (CAG) and percutaneous coronary intervention (PCI) via distal radial access (DRA) are safe and effective. Safety and efficacy of neuroangiography and neurointerventions via DRA are unknown. PURPOSE: Search the literatures on neuroangiography and neurointerventions via DRA and conduct a systematic review and meta-analysis. METHODS: PubMed, Embase and Cochrane were searched from inception to November 10, 2022. After literature screening, data extraction and assessment of literature quality, random effects model was used for meta-analysis. RESULTS: A total of 236 literatures were retrieved, and 17 literatures including 1163 patients were finally included for meta-analysis.The pooled access success rate was 0.96 (95% confidence interval, 0.94-0.98), and the heterogeneity was obvious (I2 = 55.5%). The pooled access-related complications incidence rate was 0.03 (95% confidence interval, 0.02-0.05), and the heterogeneity was not obvious (I2 = 15.8%). CONCLUSION: Neuroangiography and neurointerventions via DRA may be safe and effective. DRA is an alternative access for neuroangiography and neurointerventions.

Pearls and pitfalls in emergency CT neuroangiography through the lens of bias and error.

Computed tomography angiography (CTA) of the head and neck is central in emergency department (ED) evaluation of clinically suspected acute stroke and intracranial hemorrhage. Timely and accurate detection of acute findings is crucial for best clinical outcomes; missed or delayed diagnosis can be devastating. Our pictorial essay presents twelve CTA cases that provided significant diagnostic dilemmas to on-call trainees while reviewing current bias and error classifications in radiology. Among others, we discuss anchoring, automation, framing, satisfaction of search, scout neglect and zebra-retreat bias. Each imaging vignette depicts a potential diagnostic "pitfall" while introducing types of cognitive bias/error before concluding with a concrete "pearl" for CTA interpretation. We believe that familiarity with bias and error is particularly important in the ED setting where high case volume, high acuity and radiologist fatigue intersect. Particular attention to personal cognitive biases and these potential CTA pitfalls may help emergency radiologists transition from habit-driven pattern recognition to analytical thinking, ultimately improving diagnostic decision making.

Incidence, Clinical Significance, and Longitudinal Signal Characteristics of Ischemic Lesions Related to Diagnostic Cerebral Catheter Angiography.

PURPOSE: Cerebral DSA is a routine procedure with few complications. However, it is associated with presumably clinically inapparent lesions detectable on diffusion-weighted MRI imaging (DWI lesions). However, there are insufficient data regarding incidence, etiology, clinical relevance, and longitudinal development of these lesions. This study prospectively evaluated subjects undergoing elective diagnostic cerebral DSA for the occurrence of DWI lesions, potentially associated clinical symptoms and risk factors, and longitudinally monitored the lesions using state-of-the-art MRI. MATERIALS AND METHODS: Eighty-two subjects were examined by high-resolution MRI within 24 h after elective diagnostic DSA and lesion occurrence was qualitatively and quantitatively evaluated. Subjects' neurological status was assessed before and after DSA by clinical neurological examination and a perceived deficit questionnaire. Patient-related risk factors and procedural DSA data were documented. Subjects with lesions received a follow-up MRI and were questioned for neurological deficits after a median of 5.1 months. RESULTS: After DSA, 23(28%) subjects had a total of 54 DWI lesions. Significantly associated risk factors were number of vessels probed, intervention time, age, arterial hypertension, visible calcified plaques, and less examiner experience. Twenty percent of baseline lesions converted to persistent FLAIR lesions at follow-up. After DSA, none of the subjects had a clinically apparent neurological deficit. Self-perceived deficits were nonsignificantly higher at follow-up. CONCLUSION: Cerebral DSA is associated with a considerable number of postinterventional lesions, some persisting as scars in brain tissue. Presumably because of the small lesion size and inconsistent location, no clinically apparent neurological deficits have been observed. However, subtle self-perceived changes may occur. Therefore, special attention is needed to minimize avoidable risk factors.

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.

Neuroangiography patterns and anomalies of middle cerebral artery: A systematic review.

BACKGROUND: As the largest and most complex cerebral artery, the middle cerebral artery (MCA) patterns and anomalies are not fully reported. At present, there is confusion about the criteria for the different subtypes. The study of MCA patterns and anomalies is important because variants such as accessories or duplicates represent a high risk of failure during endovascular embolization or navigation during treatment for ischemic stroke. This study conducted a systematic review of studies on the neuroangiography patterns and anomalies of MCA. METHODS: We conducted a systematic review of four articles online databases and included English articles from PubMed, the Cochrane Library, Directory of Open Access Journals, and EBSCOhost. RESULTS: The proportion of the MCA branching pattern was 1.9% (range from 0% to 6.3%) for monofurcation, 1.0% (range from 0% to 1.4%) for tetrafurcation, 69.9% (range from 58.1% to 92.7%) for bifurcation, and 27% (ranging from 7.3% to 40.4%) for trifurcation. The proportion of MCA anomalies for accessory is 0.03% (range from 0% to 1%), duplication is 0.17% (range from 0% to 3%), and fenestration is 0.15% (range from 0% to 2%). CONCLUSION: The proportions of the branching pattern and anomalies of MCA based on the systematic review are described in this study. This study is the first to systematically review the neuroangiography pattern of MCA and neuroangiography variations/anomalies of MCA in the literature.

Simulation Training in Neuroangiography: Transfer to Reality.

PURPOSE: Endovascular simulation is an established and validated training method, but there is still no proof of direct patient's benefit, defined as lower complication rate. In this study, the impact of such a training was investigated for rehearsal of patient-specific cases as well as for a structured simulation curriculum to teach angiographer novices. MATERIALS AND METHODS: A total of 40 patients undergoing a diagnostic neuroangiography were randomized in a training and control group. In all training group patients, the angiographer received a patient-anatomy-specific rehearsal on a high-fidelity simulator prior to the real angiography. Radiation exposure, total duration, fluoroscopy time and amount of contrast agent of the real angiography were recorded. Silent cerebral ischemia was counted by magnetic resonance diffusion-weighted imaging (DWI). Additionally, the first 30 diagnostic neuroangiographies of six novices were compared (ntotal = 180). Three novices had undergone a structured simulation curriculum; three had acquired angiographic skills without simulation. RESULTS: No differences were found in the number of DWI lesions or in other quality measures of the angiographies performed with and without patient-specific rehearsal. A structured simulation curriculum for angiographer novices reduced fluoroscopy time significantly and radiation exposure. The curriculum had no influence on the total duration of the examination, the amount of contrast medium or the number of catheters used. CONCLUSION: There was no measurable benefit of patient-anatomy-specific rehearsal for an unselected patient cohort. A structured simulation-based curriculum to teach angiographic skills resulted in a reduction of fluoroscopy time and radiation dose in the first real angiographies of novice angiographers. LEVEL OF EVIDENCE: Level 4, part 1: randomized trial, part 2: historically controlled study.

Endovascular Neurosurgery in the Northern Macro-Region of Rio Grande do Sul: Part I

Introduction The city of Passo Fundo, in the north of the Rio Grande do Sul state, has been standing out in the health care field for many years. The state has become a reference in endovascular interventional neuroradiology. We will cover 10 years of experience in this area and divide our observations in 3 parts: cerebral angiograms (part I), carotid angioplasties (part II) and intracranial aneurysms (part III). The goal of part I is to statistically assess the cerebral angiograms, their indications, risks and complications, as well as to do a technical review. Materials and Methods A retrospective study from 2005 to 2015 with a total of 5,567 interventional neuroradiology procedures performed. A total of 4,114 angiograms, 639 embolizations of intracranial aneurysms, 414 carotid angioplasties, 143 embolizations of cerebral arteriovenous malformations, 32 embolizations of dural arteriovenous fistulas, 102 cerebral vasospasm treatments, 21 treatments of epistaxis, 36 embolizations of craniocervical tumor, 25 thrombolysis of ischemic stroke, 18 vertebroplasties and 13 embolizations of arteriovenous malformations of the face. Results A total of 4,084 procedures performed, 21,811 vessels studied, average vase 7.62/2.82 vessel and patient/procedure. Of these, 2,536 were diagnostic procedures and 1,548 angiographic controls. Of the total, 1,188 patients received only an angiogram, 27.14% of which were therapeutic procedures. We obtained a total of 3.89% complications: 2.33% reflection vasovagal, 0.56% allergic skin reaction, anaphylactic shock 0.07%, 0.27% femoral hematoma, 0.26% transient neurological deficit, 0.12% permanent neurological deficit and no case of death. Conclusion Cerebral angiography in adults, children and infants is a safe procedure with low risk of permanent neurological complications.

Refinement of the Hybrid Neuroendovascular Operating Suite: Current and Future Applications.

OBJECTIVE: In early-generation hybrid biplane endovascular operating rooms, switching from surgical to angiographic position is cumbersome. In this report, we highlight the unique design of a new hybrid neuroendovascular operating suite that allows surgical access to the head while keeping the biplane system over the lower body of the patient. Current and future hybrid neuroendovascular operating suite applications are discussed. METHODS: We collaborated with engineers to implement the following modifications to the design of the angiographic system: translation of the bed toward the feet to allow biplane cerebral imaging in the head-side position and the biplane left-side position; translation of the base of the A-plane C-arm away from the feet to allow increased operator space at the head of the bed and to allow cerebral imaging in both the head-side and left-side positions; use of a specialized boom mount for the display panel to increase mobility; and use of a radiolucent tabletop with attachments for the headrest or radiolucent head clamp system. RESULTS: The modified hybrid neuroendovascular operating suite allows for seamless transition between surgical and angiographic positions within seconds, improving workflow efficiency and decreasing procedure time as compared with early-generation hybrid rooms. CONCLUSIONS: Combined endovascular and surgical applications are facilitated by co-locating their respective technologies and refining the ergonomics of the system to ease transition between both sets of technologies. In so doing, hybrid neuroendovascular operating suites can be anticipated to improve patient outcomes, generate novel treatment paradigms, and improve time and cost efficiency.

Basic neuroangiography: review of technique and perioperative patient care.

Neuroangiography (NA) is an important part of diagnosis and treatment of patients with neurological disease. Although NA may be performed for diagnostic purposes, in many instances NA is performed with the intent to treat. Indications for NA range from extracranial diseases (vertebrobasilar insufficiency from subclavian steal, extracranial carotid stenosis, cavernous-carotid fistula, neck trauma, epistaxis, tumor invasion of the carotid artery, and tumor embolization) to intracranial diseases (nontraumatic subarachnoid hemorrhage, cerebral aneurysms, cerebral arteriovenous malformations, cerebral vasospasm, acute stroke, tumor embolization, and WADA test). Similar to peripheral angiography, appropriate preprocedural assessment and postprocedural care, along with understanding of anatomy, catheter technique, and disease processes, are vital to successful outcomes. This article will review the basic technique, equipment, and patient management in NA. With appropriate skill and knowledge, interventional radiologists can perform NA with safe and successful results.