A single-session stereotactic radiosurgery for vagal paraganglioma: Effective tumor reduction and innovative treatment option.

Background: Vagal paragangliomas (VPs) are rare tumors in the upper cervical region. Although surgical resection is the standard treatment for these tumors, it carries significant risks due to the tumor's high vascularity and proximity to vital structures. Stereotactic radiosurgery (SRS) for skull base paraganglioma could be a minimally invasive alternative. Case Description: We report the case of a 47-year-old man with a large, asymptomatic VP who was successfully treated with SRS with Gamma Knife Icon, which was performed in the parapharyngeal space (volume: 25.7 mL) using a marginal dose of 14 Gy to the 45% isodose line. This case illustrates the successful treatment of a lesion near the conventional limits (lower limit of C2 vertebral body) using noninvasive mask fixation. Excellent tumor control without neurological deficits was achieved for 25 months after SRS. The tumor volume decreased by 70% (final volume: 7.6 mL). Conclusion: This study demonstrates the utility of Gamma Knife Icon, which facilitates optimal SRS for upper cervical lesions, including VPs.

Novel case of ependymoma-like tumor with mesenchymal differentiation harboring ZFTA::RELA fusion in an adult.

High-grade supratentorial tumors harboring ZFTA::NCOA1/2 fusion in infants presenting with mixed histology of embryonal-appearing components resembling ependymoma and mesenchymal sarcomatous components have recently been reported as ependymoma-like tumors with mesenchymal differentiation (ELTMDs). In contrast, we describe herein a pathologically similar case with a novel ZFTA::RELA fusion in an adult. A frontal lobe lesion was resected from a 30-year-old woman and displayed mixed components on pathological examination, showing ependymoma-like and sarcomatous parts. The absence of perivascular pseudorosettes was inconsistent with a diagnosis of ependymoma. Fluorescence in situ hybridization analysis confirmed ZFTA::RELA fusion. The DKFZ methylation classifier (v12.8) did not categorize this case among established methylation classes. In addition, t-distributed stochastic neighbor embedding analysis using DNA methylation data revealed that the present case was distant from ependymomas but close to two previously reported cases of ELTMD involving ZFTA::NCOA1/2 fusion. Taken together, we concluded that this tumor should be considered under the entity of ELTMD. This represents the first description of an adult patient with ELTMD harboring ZFTA::RELA fusion analyzed by DNA methylation profiling, supporting the establishment of ELTMD as a possible new tumor type.

Association of rare variants in RNF213 with severe progression of intracranial artery stenosis in quasi-moyamoya disease.

OBJECTIVE: The genetic basis underlying the pathophysiology of quasi-moyamoya disease (qMMD) is unclear. Herein, the authors aimed to comprehensively analyze genetic variants in qMMD and investigate their association with clinical phenotypes, focusing on RNF213 and other moyamoya angiopathy (MMA)-related genes. METHODS: The authors evaluated 14 consecutive cases of qMMD, whose underlying conditions included autoimmune disease, head irradiation, meningitis/pachymeningitis, and Turner syndrome, and 9 cases of hyperthyroidism-associated MMD (hMMD). The frequencies of RNF213 p.Arg4810Lys in qMMD and hMMD were each compared to those in healthy controls and in patients with MMD. Whole-exome sequencing was performed, and rare variants (RVs) or damaging variants were analyzed in RNF213 and 36 MMA-related genes. RESULTS: The frequencies of p.Arg4810Lys were significantly higher in patients with qMMD (28.6%) and hMMD (33.3%) than in controls (1.1%; p < 0.001) and lower in the two former groups than in the MMD group (67.6%; p = 0.003 and 0.065, respectively). In qMMD, no significant clinical differences were observed based on the presence of p.Arg4810Lys. A novel RNF213 RV was identified in four cases with qMMD. These same cases also presented with significant worsening of intracranial main artery stenosis, which suggests a possible association between RNF213 RVs and the severe progression of qMMD. Among the 36 MMA-related genes, no variants correlated with specific phenotypes. CONCLUSIONS: While the clinical implications of p.Arg4810Lys in cases with qMMD were not identified, the study findings suggest a potential association between RNF213 RVs and the significant progression of intracranial artery stenosis. Genetic analysis should not focus solely on p.Arg4810Lys but instead consider a comprehensive analysis of RNF213 for more accurate clinical prognostication of qMMD.

[Genetic Analysis of Cerebrovascular Diseases].

With advances in genetic analysis technology, the genetic and molecular backgrounds of cerebrovascular diseases have become clearer. In moyamoya disease and intracranial artery stenosis, RNF213 p.Arg4810Lys has been identified as a disease susceptibility gene variant(germline variant), and various analyses have been conducted. PDGFRB mutations have been identified as characteristic somatic variants in cerebral aneurysms and are attracting attention. In addition, PIK3CA and MAP3K3 mutaions have been identified in cerebral cavernous malformations as somatic variants. Moreover, KRAS and BRAF mutations have been identified in arteriovenous malformations as somatic variants, respectively. Further studies are in progress. We reviewed the results of recent genetic analyses of cerebrovascular diseases, focusing particularly on genetic mutations.

Intracranial aneurysm stiffness assessment using 4D Flow MRI.

BACKGROUND: Although arterial stiffness is known as a biomarker for cardiovascular events and stroke, there is limited information in the literature regarding the stiffness of intracranial aneurysms. In this study, we aim to assess the stiffness of intracranial aneurysms using 4D Flow MRI. METHODS: A total of 27 aneurysms in 25 patients with internal carotid artery aneurysms were included in this study. Using 4D Flow MRI, we measured the arterial pulse wave form during a cardiac cycle at planes proximal and distal to the target aneurysm. The damping of these waveforms through the aneurysm was defined as the aneurysm damping index (ADI) and compared to the contralateral side. We also investigated the clinical factors related to the ADI. RESULTS: ADI assessment was successful in all cases. The average ADI was 1.18±0.28, which was significantly larger than 1.0 (P=0.0027 [t-test]). The ADI on the aneurysm side was larger than on the contralateral side (1.19±0.30 vs 1.05±0.17, P=0.029 [t-test]). On multivariate analysis, the use of beta-blockers (ß=0.46, P=0.015) and smoking history (ß=-0.22, P=0.024) showed a significant correlation with ADI. CONCLUSION: We have proposed a novel method to observe arterial pulse wave dumping through intracranial aneurysm using 4D Flow MRI. The damping can be quantitatively observed, and the ADI has correlations with clinical factors such as antihypertensive drugs and smoking. Further studies should focus more on evaluating aneurysm stiffness and its clinical applications.

AB019. Detailed analysis of DNA hydroxymethylation observed with the malignant progression of IDH-mutant gliomas.

BACKGROUND: Gliomas vary in prognosis with World Health Organization (WHO) grade. Low-grade gliomas can undergo malignant progression (MP), becoming aggressive high-grade tumors, worsening prognosis. This is prevalent in isocitrate dehydrogenase-mutant (IDH-mt) gliomas like astrocytoma and oligodendroglioma, but the mechanism of MP is still not fully understood. High-grade IDH-mt gliomas have been reported to exhibit TET-mediated DNA hydroxymethylation, which is suggested to potentially influence gene expression. We hypothesized that hydroxymethylation in specific regions could be implicated in triggering MP. METHODS: We collected glioma tumor samples over a decade, using WHO 2021 classification to study IDH-mt astrocytoma grade 2 progression to grades 3 or 4, indicating MP. Samples from five patients, demonstrating MP, were analyzed for DNA hydroxymethylation status across more than 850,000 genomic locations using the oxidative bisulfite process and Infinium EPIC methylation array. This was complemented by RNA sequencing for gene expression analysis and its correlation with hydroxymethylation, and motif-enrichment analysis to infer transcription factor involvement in hydroxymethylation-based gene regulation. Additionally, to delve into the fundamental causes of hydroxymethylation, we exposed an IDH-mt glioma cell line to hypoxic conditions and systematically explored the genomic locations where hydroxymethylation occurred. RESULTS: Our comprehensive analysis identified a significant overlap of hydroxymethylated genomic regions across samples during MP, with a notable enrichment in open sea and intergenic regions (P<0.001). These regions were significantly associated with cancer-related signalling pathways. Integration with RNA sequencing data revealed 91 genes with significant correlations between hydroxymethylation and gene expression, implying roles in cell cycle regulation and antineoplastic functions. Furthermore, motif-enrichment analysis suggested the potential regulatory role of KLF4 in these processes. The cell culture results revealed that a certain similarity exists between the hydroxymethylation patterns observed during MP and those in glioma cells cultured under hypoxic conditions. CONCLUSIONS: This study elucidates the importance of region-specific DNA hydroxymethylation in the MP of IDH-mt astrocytomas, suggesting its potential impact on gene expression relevant to cancer malignancy. Our findings propose a complex interplay between hydroxymethylation and gene regulation, which may offer new insights into the mechanisms driving glioma progression and highlight potential targets for therapeutic intervention.

Collision of pituitary neuroendocrine tumor and anterior clinoid meningioma treated with a two-stage minimally invasive surgical strategy: illustrative case.

BACKGROUND: The locations of pituitary neuroendocrine tumor (PitNET) and anterior clinoid meningioma (ACM) appear to be very close but essentially different, as the former is inside the sella turcica while the latter is in the intradural space. A collision tumor thus requires a specific treatment strategy but has been rarely reported. OBSERVATIONS: A 77-year-old woman presented with progressive visual impairment due to significant compression of the optic apparatus by a collision of PitNET and ACM. With a minimally invasive two-stage therapeutic strategy, the ACM was first resected using an endoscopic mini-pterional approach, then the PitNET was removed with an endoscopic transnasal approach 8 weeks later, leading to significant improvement in visual function. The authors' literature search identified only 2 documented cases of a similar collision. LESSONS: This case underscores the complexity of the decision-making process in the management of collision tumors and suggests the potential benefit of staged minimally invasive surgical interventions in preserving visual function. Further accumulation of cases is warranted for refining the treatment strategy. https://thejns.org/doi/10.3171/CASE24240.

Endoscopic endonasal drainage of a middle fossa epidural abscess in conjunction with endoscopic sinus surgery: illustrative case.

BACKGROUND: Recent anatomical studies have reported the feasibility of the endoscopic endonasal approach to the middle fossa. However, its clinical applicability has been discussed in only a few cases. This article describes the case of a middle fossa epidural abscess successfully drained through a fully endoscopic endonasal corridor and discusses the key technical points. OBSERVATIONS: The authors describe an 8-year-old boy who presented with worsening headache, fatigue, emesis, and fever and was diagnosed with a left middle fossa epidural abscess associated with sphenoid sinusitis. Following endoscopic sinus surgery performed by a rhinologist, the middle fossa was accessed by removing the maxillary strut through the transmaxillary transpterygoid corridor. Complete drainage of the abscess was confirmed on postoperative magnetic resonance imaging. The patient tolerated the surgery without neurological deficit and demonstrated prompt symptom improvement. He was discharged home after completing a 6-week course of antibiotic therapy and remained free from recurrence at 1 year following surgery. LESSONS: The endoscopic endonasal approach may be applicable to a middle fossa epidural abscess, resulting in prompt clinical improvement. The maxillary strut is a key structure for entering the middle fossa. https://thejns.org/doi/10.3171/CASE24288.

Influence of an improvement in frontal lobe hemodynamics on neurocognitive function in adult patients with moyamoya disease.

BACKGROUND: In adults, moyamoya disease (MMD) often presents with slight neurocognitive impairment, which may result from frontal lobe hemodynamic insufficiency. METHODS: In this study, we performed revascularization surgery by superficial temporal artery-anterior cerebral artery (ACA) direct bypass in 20 adults with MMD with poor anterograde ACA flow (Group M). The pre- and postoperative neurocognitive test results of these patients were retrospectively analyzed. The comparative group (Group C) included 23 patients with unruptured aneurysms or brain tumors who underwent craniotomy, as well as the same neurocognitive tests as Group M. We calculated the compositive frontal lobe function index (CFFI) based on the results of seven neurocognitive tests for each patient, and the difference between the pre- and postoperative CFFI values (CFFI Post - Pre) was compared between the two groups. RESULTS: Frontal perfusion improved postoperatively in all patients in Group M. The CFFI Post - Pre was significantly higher in Group M than in Group C (0.23 ± 0.44 vs. - 0.20 ± 0.32; p < 0.001). After adjusting for postoperative age, sex, preoperative non-verbal intelligence quotient, and preoperative period of stress, Group M had a significantly higher CFFI Post - Pre than Group C in the multiple regression analysis (t value = 4.01; p < 0.001). CONCLUSION: Improving frontal lobe hemodynamics might be the key for improving neurocognitive dysfunction in adults with MMD. The surgical indication and method should be considered from the perspective of both stroke prevention and neurocognitive improvement or protection.

Endoscopic Endonasal Approach Is Superior to Transcranial Approach for Small to Medium Tuberculum Sellae Meningiomas in Terms of Visual Outcome and Complications: A Retrospective Study in a Single Center.

OBJECTIVE: This study compared the effectiveness of the endoscopic endonasal approach (EEA) with the conventional transcranial approach (TCA) for treating tuberculum sellae meningiomas (TSMs), aiming to identify the superior surgical method and the risk factors affecting outcomes. METHODS: Patients treated for TSM from 1998 to 2023 at our institution were retrospectively analyzed, evaluating patient characteristics, tumor features, outcomes, and complications. A novel grading system for preoperative evaluation of TSMs was proposed. RESULTS: Among 49 patients, 26 underwent EEA and 23 underwent TCA. The maximum diameters were comparable between the groups (mean 22 mm vs. 23 mm). Gross total resection rates were 62% for EEA and 70% for TCA, showing no significant difference. However, postsurgical visual improvement was significantly higher in the EEA group compared with the TCA group (77% vs. 44%; P = 0.020), with fewer complications in the EEA group (8% vs. 35%; P = 0.032). CONCLUSIONS: EEA is a safe and effective treatment approach for small to medium TSMs, with outcomes comparable to TCA in terms of resection but superior in visual improvement and fewer complications. Selection of surgical approach should consider patient and tumor characteristics as well as surgeon experience.

Accurate Preoperative and Intraoperative Evaluation Reduces Surgical Costs and Patient Invasiveness in Ventriculoperitoneal Shunt Revision.

The ventriculoperitoneal (VP) shunt is one of the most common surgical procedures in neurosurgery, frequently resulting in malfunctions. Shunt malfunctions, which can include mechanical failure, obstruction, infection, or disconnection, occur in a significant percentage of patients, often necessitating multiple revisions. These revisions can lead to increased healthcare costs due to additional surgeries or treatments. Therefore, addressing the economic impacts of these revisions is crucial. Our report presents a cost-effective approach to shunt revisions, demonstrated through a case study of an 82-year-old woman with hydrocephalus. Although initially treated with a VP shunt, she required a revision after six years due to shunt malfunction. Through comprehensive preoperative and intraoperative evaluations, including a shuntogram with iodine contrast and meticulous examination, we identified the cause of malfunction as a connective tissue sac blocking the peritoneal catheter. The surgery involved flushing the catheter lumen with saline to confirm the obstruction and careful removal of the obstructive tissue. This accurate diagnosis facilitated a minimally invasive revision, enabling the reuse of existing shunt components and avoiding the need for new devices, thus reducing costs and surgical invasiveness. Our study serves as a call to action for healthcare providers and surgeons to consider more cost-effective and patient-friendly approaches in managing VP shunt malfunctions, ultimately benefiting both the healthcare system and the patients it serves.

Sustaining consistent cobalt-60 dose rate enhances radiosurgical outcomes in brain arteriovenous malformation management.

BACKGROUND AND PURPOSE: The impact of cobalt-60 dose rate (Co-60 DR) on outcomes of stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs) remains fully elucidated. This study explored the association between Co-60 DR and SRS outcomes in AVM treatment. MATERIALS AND METHODS: 772 AVM patients from 1990 to 2020 were included. High DR was defined as ≥ 2.4 Gy/min. AVM patients were categorized into 3 cohorts based on the nidus volume: small (<5 mL), medium (≥5 mL and < 10 mL), and large (≥10 mL). The primary endpoint was AVM obliteration; secondary endpoints included post-SRS hemorrhage. RESULTS: Cumulative obliteration rates of the large AVM were significantly increased in the high DR group than those in the low DR group (84 % vs. 45 % at 5 years, log-rank test; p = 0.011). Multivariable analysis showed that the obliteration rate was significantly elevated for the high DR group in the large AVM cohort with an adjusted hazard ratio (HR) of 1.78 (95 % confidence interval [CI]: 1.00-3.17, p = 0.049). Post-SRS hemorrhage rates of the entire cohort were significantly decreased in the high DR group than in the low DR group (2.5 % vs. 5.3 % at 5 years, log-rank test; p = 0.035). Multivariable analysis revealed post-SRS hemorrhage was reduced in the high DR group with an adjusted HR of 0.47 (95 % CI: 0.24-0.92, p = 0.026). CONCLUSION: High DR may lead to increased efficiency for large AVMs and decreased post-SRS hemorrhage in all AVM cases. Sustaining a higher Co-60 DR could potentially yield favorable outcomes for SRS for AVMs.

Intrasellar chordoma masquerading as a pituitary neuroendocrine tumor: Illustrative case.

Background: Chordomas are rare, locally aggressive neoplasms recognized as derivatives of the notochord vestiges. These tumors typically involve the midline axial skeleton, and intracranial chordomas exhibit proclivity for the spheno-occipital region. However, purely intrasellar occurrences are extremely rare. We report a case of intrasellar chordoma, which masqueraded as a pituitary neuroendocrine tumor. Case Description: An 87-year-old female presented with an acutely altered mental state after a few-week course of headaches and decreased left vision. Adrenal insufficiency was evident, and magnetic resonance imaging revealed an intrasellar lesion with heterogeneous contrast enhancement and marked T2 hyperintensity. Central adrenal insufficiency due to an intrasellar lesion was suspected. Cortisol replacement was initiated, and transsphenoidal surgery was performed. Anterosuperior displacement of the normal pituitary gland and the absence of the bony dorsum sellae were notable during the procedure. Histological examination led to a diagnosis of conventional chordoma, and upfront adjuvant stereotactic radiosurgery was executed. She has been free from tumor progression for 12 months. Conclusion: This case and literature review suggested that the pathognomonic features of intrasellar chordoma were heterogeneous contrast enhancement, marked T2 hyperintensity, osteolytic destruction of the dorsum sellae, and anterosuperior displacement of the pituitary gland. Clinical outcomes seemed slightly worse than those of all skull base chordomas, which were the rationale for upfront radiosurgery in our case. Neurosurgeons should include intrasellar chordomas in the differential diagnosis of intrasellar lesions, carefully dissect them from the adjacent critical anatomical structures, and consider upfront radiosurgery to achieve optimal patient outcomes.

Patient-specific cerebral 3D vessel model reconstruction using deep learning.

Three-dimensional vessel model reconstruction from patient-specific magnetic resonance angiography (MRA) images often requires some manual maneuvers. This study aimed to establish the deep learning (DL)-based method for vessel model reconstruction. Time of flight MRA of 40 patients with internal carotid artery aneurysms was prepared, and three-dimensional vessel models were constructed using the threshold and region-growing method. Using those datasets, supervised deep learning using 2D U-net was performed to reconstruct 3D vessel models. The accuracy of the DL-based vessel segmentations was assessed using 20 MRA images outside the training dataset. The dice coefficient was used as the indicator of the model accuracy, and the blood flow simulation was performed using the DL-based vessel model. The created DL model could successfully reconstruct a three-dimensional model in all 60 cases. The dice coefficient in the test dataset was 0.859. Of note, the DL-generated model proved its efficacy even for large aneurysms (> 10 mm in their diameter). The reconstructed model was feasible in performing blood flow simulation to assist clinical decision-making. Our DL-based method could successfully reconstruct a three-dimensional vessel model with moderate accuracy. Future studies are warranted to exhibit that DL-based technology can promote medical image processing.

Stroke Events and Risk Factors in Older Patients with Moyamoya Disease.

BACKGROUND: We aimed to comprehensively analyze the epidemiology, natural history, stroke events and their risk factors, and the RNF213 p.Arg4810Lys variant in older patients with moyamoya disease (MMD). METHODS: We enrolled patients with MMD followed-up at our hospital between 2000 and 2023. Those who developed MMD at age ≥60 years or were diagnosed at a younger age and followed-up after age 60 years were included. Baseline characteristics, onset type, radiologic features, and RNF213 p.Arg4810Lys variant status were investigated. RESULTS: Among 56 patients with 100 affected hemispheres, 62 were asymptomatic, 26 experienced ischemic onset, and 12 had hemorrhagic onset. A higher incidence of anterior choroidal artery (AchA) dilatation and lower proportion of favorable modified Rankin scale scores were detected in hemorrhagic onset, whereas greater prevalence of bypass surgery in ischemic onset. Of 76 asymptomatic hemispheres at the age of 60 years, subsequent stroke events occurred in 10 hemispheres, comprising 8 hemorrhages and 2 ischemias. Risk factors for de novo hemorrhage in asymptomatic hemispheres included AchA dilatation and choroidal anastomosis. Comparison of the RNF213 p.Arg4810Lys variant status showed no significant differences in baseline characteristics, onset types, or imaging findings, except for a higher percentage of patients in the GA group with a family history of MMD. CONCLUSIONS: Hemorrhagic events were the most prevalent and prognostically deteriorating factors in older patients with MMD aged ≥60 years. AchA dilatation and choroidal anastomosis were predictors of de novo hemorrhage in asymptomatic nonsurgical hemispheres in older patients with MMD.

Clinical and radiological features of intracranial ancient schwannomas: a single-institution, retrospective analysis.

Ancient schwannoma (AS) is a subtype of schwannoma characterized by slow progression despite degenerative changes in pathology. Although it is considered a benign tumor, most previous reports have focused on extracranial AS; therefore, the clinical characteristics of intracranial AS is not clear. We included 174 patients who underwent surgery for sporadic intracranial schwannoma, and 13 patients (7.5%) were diagnosed with AS. Cysts were significantly more common in patients with AS than conventional schwannomas (92.3% vs. 44.7%, p < 0.001), as was bleeding (38.5% vs. 6.9%, p = 0.003) and calcification (15.4% vs. 1.3%, p = 0.029). The maximum tumor diameter was also larger in patients with AS (35 mm vs. 29 mm, p = 0.017). The median duration from symptom onset to surgery (7.0 vs. 12.5 months, p = 0.740) did not significantly differ between groups, nor did the probability of postoperative recurrence (p = 0.949). Intracranial AS was strongly associated with cyst formation and exhibited a benign clinical course with a lower rate of recurrence and need for salvage treatment. Extracranial AS is reportedly characterized by a slow progression through a long-term clinical course, whereas intracranial AS did not progress slowly in our study and exhibited different clinical features to those reported for extracranial AS.

Association of Genetic Variants with Postoperative Donor Artery Development in Moyamoya Disease: RNF213 and Other Moyamoya Angiopathy-Related Gene Analysis.

Robust postoperative bypass development is a characteristic of moyamoya disease (MMD); however, genetic factors mediating this phenomenon remain incompletely understood. Therefore, we aimed to elucidate the relationship between postoperative donor artery development and genetic variants. We retrospectively enrolled 63 patients (79 hemispheres) who underwent combined revascularization surgery. Postoperative development of the superficial temporal artery (STA), middle meningeal artery, and deep temporal artery (DTA) was assessed using the caliber-change ratio determined from magnetic resonance angiography measurements. We analyzed RNF213 and 36 other moyamoya angiopathy-related genes by whole-exome sequencing and extracted rare or damaging variants. Thirty-five participants carried RNF213 p.Arg4810Lys (all heterozygotes), whereas 5 had RNF213 rare variants (RVs). p.Arg4810Lys was significantly associated with postoperative DTA development, while age at surgery, hypertension, and hyperlipidemia were inversely associated. Multiple regression analysis revealed that age and p.Arg4810Lys held statistical significance (P = 0.044, coefficient - 0.015, 95% confidence interval (CI) - 0.029 to 0.000 and P = 0.001, coefficient 0.670, 95% CI 0.269 to 1.072, respectively). Those with RNF213 RV without p.Arg4810Lys exhibited a significant trend toward poor DTA development (P = 0.001). Hypertension demonstrated a significant positive association with STA development, which remained significant even after multiple regression analysis (P = 0.001, coefficient 0.303, 95% CI 0.123 to 0.482). Following Bonferroni correction for multiple comparisons, targeted analyses of RNF213 and 36 moyamoya angiopathy-related genes showed a significant association of only RNF213 p.Arg4810Lys with favorable DTA development (P = 0.001). A comprehensive analysis of RNF213, considering both p.Arg4810Lys and RVs, may provide a clearer prediction of postoperative DTA development.

A bibliometric analysis of the 100 most-cited clinical articles in the research of intracranial artery stenosis and intracranial atherosclerosis.

Background: Intracranial arterial stenosis (ICAS), caused by intracranial atherosclerosis, is one of the major causes of ischemic stroke. This study identified the top 100 most-cited publications on ICAS through a bibliometric analysis. Methods: Two independent authors conducted a search in the Web of Science database for clinical articles on ICAS published between 1993 and 2022. The top 100 most-cited articles were then extracted. For each article, the analysis covered the title, author, country of origin/affiliation, journal, total number of citations, number of citations per year, and type of study. Results: The top 100 most-cited papers in the ICAS were authored by 565 authors from 12 countries and published in 29 journals. In terms of the 5-year trend, the largest number of papers were published between 2003 and 2007 (n = 31). The median number of citations for the 100 papers was 161 (range 109-1,115). The journal with the highest proportion of the 100 most published articles was Stroke, accounting for 41% of articles and 37% of the citations. According to country of origin, the United States of America accounted for the largest number of articles, followed by China, Japan, and South Korea, with these four countries together accounting for 81% of the total number of articles and 88% of the citations. Trends in the past five years included the use of terms such as acute ischemic stroke and mechanical thrombectomy. Conclusion: The findings of this study provide novel insight into this field and will facilitate future research endeavors.