Knowledge domain and emerging trends in the rupture risk of intracranial aneurysms research from 2004 to 2023

Abstract

BACKGROUND

Intracranial aneurysms (IAs) pose significant health risks, attributable to their potential for sudden rupture, which can result in severe outcomes such as stroke and death. Despite extensive research, the variability of aneurysm behavior, with some remaining stable for years while others rupture unexpectedly, remains poorly understood.

AIM

To employ bibliometric analysis to map the research landscape concerning risk factors associated with IAs rupture.

METHODS

A systematic literature review of publications from 2004 to 2023 was conducted, analyzing 3804 documents from the Web of Science Core Collection database, with a focus on full-text articles and reviews in English. The analysis encompassed citation and co-citation networks, keyword bursts, and temporal trends to delineate the evolution of research themes and collaboration patterns. Advanced software tools, CiteSpace and VOSviewer, were utilized for comprehensive data visualization and trend analysis.

RESULTS

Analysis uncovered a total of 3804 publications on IA rupture risk factors between 2006 and 2023. Research interest surged after 2013, peaking in 2023. The United States led with 28.97% of publications, garnering 37706 citations. Notable United States-China collaborations were observed. Capital Medical University produced 184 publications, while Utrecht University boasted a citation average of 69.62 per publication. “World Neurosurgery” published the most papers, contrasting with “Stroke”, the most cited journal. The PHASES score from “Lancet Neurology” emerged as a vital rupture risk prediction tool. Early research favored endovascular therapy, transitioning to magnetic resonance imaging and flow diverters. “Subarachnoid hemorrhage” stood out as a recurrent keyword.

CONCLUSION

This study assesses global IA research trends and highlights crucial gaps, guiding future investigations to improve preventive and therapeutic approaches.

Key Words: Bibliometric, VOSviewer, CiteSpace, Intracranial aneurysm, Risk factor

Core Tip: This bibliometric analysis provides a comprehensive overview of research on risk factors associated with intracranial aneurysms (IAs) rupture. Highlighting global trends and collaborations, it identifies key publications, influential journals, and evolving research themes. Notably, the study emphasizes the increasing research interest post-2013 and the pivotal role of tools like the PHASES score in predicting rupture risks. By synthesizing two decades of data, this analysis offers valuable insights into the dynamic landscape of IAs studies, guiding future investigations and enhancing preventive and therapeutic strategies.

INTRODUCTION

Unruptured intracranial aneurysms (UIAs) are localized, pathological dilations of the intracranial arterial wall that pose a significant risk of rupture[1]. The prevalence of UIAs is notably elevated, as evidenced by a comprehensive systematic review and meta-analysis spanning 21 countries, 83 study populations, and 94912 UIA patients. Within a cohort of asymptomatic adults aged 50 years, the collective prevalence of UIA was approximately 3.2% (95% confidence interval: 1.9%-5.2%)[2]. Given the grave implications of aneurysmal subarachnoid hemorrhage, a severe complication of UIAs with a mortality rate of 67%, and a substantial proportion of survivors who are left disabled[3,4], it is imperative for clinicians to discern the risk of rupture. The evolving landscape of our understanding of the risk factors associated with UIAs underscores the need for continued investigation. Past studies have indicated the dichotomous behavior of aneurysms, with some exhibiting rapid enlargement and rupture within a condensed timeframe while others remaining stable over prolonged periods[2]. The exploration of risk factors contributing to aneurysm rupture has been a focal point of numerous studies[4-8].

Various systematic methodologies exist for comprehensively mapping an academic domain, with bibliometric analysis emerging as the predominant approach due to advancements in mathematics and computation[9]. Bibliometrics not only allows for qualitative and quantitative evaluation of author contributions, organizational collaborations, country affiliations, and journal impact but also facilitates the assessment of emerging trends and developments in academic research, a task beyond the scope of traditional reviews, meta-analyses, and experimental studies[9-12]. Consequently, bibliometrics plays an increasingly crucial role in trend analysis and guideline development, making bibliometrics a valuable tool for assessing and surveying studies related to the risk factors for IA rupture. In this study, CiteSpace and VOSviewer, two prominent bibliometric software tools, were used to delineate the knowledge base and emerging trends within studies related to the risk factors for IA rupture from key perspectives[13,14]. These perspectives encompass quantifying information on rupture risk factors for IAs, including individual impacts and collaborative efforts based on annual publications, journals, co-cited publications, countries, authors, and co-cited authors. Additionally, the study identifies the most cited articles through co-citation analyses to evaluate the foundational knowledge in this area. Furthermore, this research aims to uncover the evolution of knowledge structures and key areas of interest through keyword and co-cited reference burst analyses. Subsequently, this study sought to determine the research content and potential future development directions in this field by analyzing the top 50 articles’ journals, co-cited journals, countries, and keywords.

MATERIALS AND METHODS

Literature search

The bibliographic classification accuracy of the Web of Science Core Collection (WoSCC) surpasses that of any other database, rendering it the optimal choice for bibliographic analysis. Hence, we opted to conduct our search within this database. On March 12, 2024, we searched the WoS for articles spanning from 2004 to December 31, 2023, pertaining to the risk factors for IA rupture. The search query employed was as follows: (((((((((((((((((((((((((((((((((((((((((((TS = (intracranial aneurysm)) OR TS = (Intracranial Aneurysm)) OR TS = (Aneurysms, Intracranial)) OR TS = (Intracranial Aneurysms)) OR TS = (Aneurysm, Intracranial)) OR TS = (Aneurysm, Anterior Communicating Artery)) OR TS = (Anterior Communicating Artery Aneurysm)) OR TS = (Aneurysm, Basilar Artery)) OR TS = (Aneurysms, Basilar Artery)) OR TS = (Artery Aneurysm, Basilar)) OR TS = (Artery Aneurysms, Basilar)) OR TS = (Basilar Artery Aneurysms)) OR TS = (Basilar Artery Aneurysm)) OR TS = (Aneurysm, Middle Cerebral Artery)) OR TS = (Middle Cerebral Artery Aneurysm)) OR TS = (Aneurysm, Posterior Cerebral Artery)) OR TS = (Posterior Cerebral Artery Aneurysm)) OR TS = (Berry Aneurysm)) OR TS = (Aneurysm, Berry)) OR TS = (Aneurysms, Berry)) OR TS = (Berry Aneurysms)) OR TS = (Brain Aneurysm)) OR TS = (Aneurysm, Brain)) OR TS = (Aneurysms, Brain)) OR TS = (Brain Aneurysms)) OR TS = (Cerebral Aneurysm)) OR TS = (Aneurysms, Cerebral)) OR TS = (Cerebral Aneurysms)) OR TS = (Aneurysm, Cerebral)) OR TS = (Giant Intracranial Aneurysm)) OR TS = (Aneurysm, Giant Intracranial)) OR TS = (Giant Intracranial Aneurysms)) OR TS = (Intracranial Aneurysm, Giant)) OR TS = (Intracranial Aneurysms, Giant)) OR TS = (Mycotic Aneurysm, Intracranial)) OR TS = (Aneurysm, Intracranial Mycotic)) OR TS = (Aneurysms, Intracranial Mycotic)) OR TS = (Intracranial Mycotic Aneurysm)) OR TS = (Intracranial Mycotic Aneurysms)) OR TS = (Mycotic Aneurysms, Intracranial)) OR TS = (Aneurysm, Anterior Cerebral Artery)) OR TS = (Anterior Cerebral Artery Aneurysm)) OR TS = (Aneurysm, Posterior Communicating Artery)) OR TS = (Posterior Communicating Artery Aneurysm) AND TS = (Risk Factor). The literature screening for this study was based on the following inclusion criteria: (1) Full-text publications related to risk factors for the rupture of IAs; (2) Articles and review manuscripts written in English; and (3) Publications dated between January 1, 2004, and December 31, 2023. The exclusion criteria were as follows: (1) Irrelevant to the topic of risk factors for the rupture of IAs; and (2) Conference abstracts, news articles, brief reports, or similar formats. A plain text version of the selected papers was exported (Figure 1).

Figure 1 Flowchart of study identification and selection. WoSCC: Web of Science Core Collection.

Analysis

The annual publications, national trends, and proportions of papers were analyzed and visualized using GraphPad Prism v8.0.2. Additionally, CiteSpace (6.2.4R 64-bit Advanced Edition) and VOSviewer (version 1.6.18) were employed for further analysis of the data, facilitating the visualization of scientific knowledge maps. VOSviewer version 1.6.17, created by van Eck and Waltman et al[13], is a Java-based free software designed for analyzing large volumes of literature data and displaying them in map format. To visualize the research outcomes of a specific field by drawing a co-citation network map, Professor Chao-Mei Chen developed CiteSpace (version 6.2.4R) software[15]. This software envisions using an experimental framework to explore new concepts and evaluate existing technologies. It enables users to gain a better understanding of knowledge domains, research frontiers, and trends, thereby predicting future research advancements[16,17].

RESULTS

Overall distribution

The results indicate that from January 1, 2006, to December 31, 2023, there were a total of 3804 literature entries on risk factors for the rupture of IAs in the WoSCC database, comprising 3346 articles (94.31%) and 458 reviews (5.69%). These publications span 96 countries and regions, involve 3061 institutions, and include contributions from 14902 authors.

Since 2004, the annual publication output has shown a gradual increase (Figure 2). We divided this trend into three phases: A slow growth period from 2004 to 2009 (Figure 2) with an annual publication count of less than 100, indicating a lack of attention from researchers in the field; a gradual increase in publications from 2010 to 2012, signifying increased interest from researchers; and a rapid surge in publications after 2013, reaching a peak in 2023, indicating widespread attention to the field since 2013.

Figure 2  The annual trend publications related to risk factors for the rupture of intracranial aneurysms from 2004 to 2023.

Countries/regions and institutions analysis

Research on the risk factors for IA rupture has been conducted in 96 countries and regions. Figures 3 and 4 illustrate the annual publication output of the top 10 countries in the past decade. The top 5 countries in this field are the United States, China, Japan, Germany, and South Korea. The United States accounts for 28.97% of the total publication output, significantly surpassing other nations.

Figure 3  Number of articles by publication in countries.

Figure 4  Publication output heatmap by countries.

Among the top ten countries/regions in terms of publication output, the United States’s papers were cited 37706 times (Table 1), significantly exceeding all other countries/regions. Its citation-to-publication ratio (34.22) ranks 6^th among all countries, indicating generally high-quality publications. China ranks 2^nd in publication output (847 papers) and 5^th in citation count (8992 times), with a citation-to-publication ratio of 10.62. The collaboration network, as depicted in Figure 5A, shows close collaboration between the most prolific producers, the United States and China. The United States collaborates closely with Germany, France, and Italy, among others, while China’s collaborations are more pronounced with Japan, South Korea, and the Netherlands. The United States not only leads in publication output and citation frequency but also exhibits a centrality of 0.32, signifying its position as a leading nation in the field.

Figure 5 Co-occurrence map of nations/regions and organizations in risk factors for the rupture of intracranial aneurysms studies. A: Co-occurrence map of nations/regions in risk factors for the rupture of intracranial aneurysms studies; B: Co-occurrence map of organizations in risk factors for the rupture of intracranial aneurysms studies.

Table 1 The top 10 countries/regions and institutions involved in risk factors for the rupture of intracranial aneurysms research.

Rank	Country/region	Article counts	Centrality	Percentage (%)	Citation	Citation per publication
1	United States	1102	0.32	28.97	37706	34.22
2	China	847	0.12	22.27	8992	10.62
3	Japan	416	0.08	10.94	10264	24.67
4	Germany	314	0.1	8.25	9871	31.44
5	South Korea	275	0.04	7.23	3546	12.89
6	Netherlands	213	0.03	5.60	13789	64.74
7	England	169	0.11	4.44	6994	41.38
8	Canada	157	0.08	4.13	7488	47.69
9	France	151	0.14	3.97	6985	46.26
10	Italy	149	0.05	3.92	5599	37.58

A total of 3061 institutions have systematically published articles on risk factors for IA rupture. Among the top ten institutions in terms of publication output, 4 are from the United States, 2 are from China, 2 are from Finland, 1 is from the Netherlands, and 1 is from Canada (Table 2, Figure 5B). Capital Medical University has the greatest number of publications (184 papers, 1920 citations, averaging 10.43 citations per paper). Utrecht University (149 papers, 10373 citations, averaging 69.62 citations per paper) ranks second, followed by Mayo Clinic (134 papers, 6645 citations, averaging 49.59 citations per paper) in third place and Harvard University (128 papers, 3299 citations, averaging 25.77 citations per paper) in fourth place.

Table 2 The top 10 institutions of intracranial aneurysms rupture risk factors research.

Rank	Institution	Country	Number of studies	Total citations	Average citation
1	Capital Medical University	China	184	1920	10.43
2	Utrecht University	Netherlands	149	10373	69.62
3	Mayo Clinic	United States	134	6645	49.59
4	Harvard University	United States	128	3299	25.77
5	University of California System	United States	101	3257	32.25
6	Harvard Medical School	United States	101	2778	27.50
7	University of Helsinki	Finland	95	5978	62.93
8	Beijing Neurosurgical Institute	China	85	1070	12.59
9	Helsinki University Central Hospital	Finland	78	4080	52.31
10	University of Toronto	Canada	70	4338	61.97

Journals and co-cited academic journals

Tables 3 and 4 present the top 10 journals with the highest publication output and most citations. “World Neurosurgery” (320 papers, 8.41%) is the journal with the highest number of publications in this field, followed by “Journal of Neurosurgery” (218 papers, 5.73%), “Stroke” (172 papers, 4.52%), and “Neurosurgery” (158 papers, 4.15%). Among the top 10 journals by publication output, “Cell Death & Disease” has the highest impact factor (IF) of 9.0. Approximately 90% of the journals are classified as Q1 or Q2 (Figure 6A).

Figure 6 Density map of journals and co-cited journals in risk factors for the rupture of intracranial aneurysms research. A: Density map of journals in risk factors for the rupture of intracranial aneurysms research; B: Density map of co-cited journals in risk factors for the rupture of intracranial aneurysms research.

Table 3 The top 10 journals of intracranial aneurysms rupture risk factors research.

Rank	Journal	Article counts	Percentage (%)	IF	Quartile in category
1	World Neurosurgery	320	8.41	2.0	Q4
2	Journal of Neurosurgery	218	5.73	5.6	Q1
3	Stroke	172	4.52	5.2	Q2
4	Neurosurgery	158	4.15	4.7	Q2
5	Acta Neurochirurgica	123	3.23	9.0	Q1
6	Frontiers in Neurology	113	2.97	3.7	Q2
7	Journal of Neurointerventional Surgery	102	2.68	3.8	Q1
8	American Journal of Neuroradiology	87	2.29	3.3	Q2
9	Journal of Clinical Neuroscience	80	2.10	4.2	Q2
10	Clinical Neurology and Neurosurgery	66	1.74	4.8	Q1

IF: Impact factor.

Table 4 The top 10 co-cited journals related with rupture risk factors of intracranial aneurysms research.

Rank	Cited Journal	Co-citation	IF (2022)	Quartile in category
1	Stroke	3230	11.2	Q1
2	J Neurosurg	2756	13.3	Q1
3	Neurosurgery	2674	3.7	Q2
4	Am J Neuroradiol	1864	4.8	Q1
5	Lancet	1827	64.5	Q4
6	Neurology	1525	11.5	Q1
7	New Engl J Med	1509	8.0	Q1
8	World Neurosurg	1375	254.7	Q1
9	Acta Neurochir	1339	64.8	Q1
10	Lancet Neurol	1215	4.8	Q2

IF: Impact factor.

The impact of a journal is determined by the frequency of its co-citation, indicating whether the journal has made a significant impact on the scientific community. According to Figure 6B and Table 4, the most co-cited journal was “Stroke” (3230 citations), followed by “J Neurosurg” (2756 citations) and “Neurosurgery” (2674 citations). Among the top 10 most co-cited journals, “Lancet” has been cited 1827 times, with the highest IF among the top 10 journals (168.9). In the co-cited journals, 90% of the journals are in the Q1/Q2 categories.

The distribution of academic publications by topic is displayed through a double-map overlay (Figure 7). The colored trajectories represent citation connections, with citing journals on the left and cited journals on the right. Based on the results, we identified 7 main colored citation paths. For example, research published in molecular/biology/immunology journals is primarily cited by research published in molecular/biology/genetics journals. Similarly, research published in medicine/medical/clinical journals is mainly cited by research published in molecular/biology/genetics, health/nursing/medicine, and psychology/education/social journals. Additionally, research published in neurology/sports/ophthalmology journals is primarily cited by research published in molecular/biology/genetics, health/nursing/medicine, and psychology/education/social journals.

Figure 7 The dual-map overlay of periodicals associated with risk factors for the rupture of intracranial aneurysms research. The citing journals are on the left, the cited journals are on the right, and the line path represents the citation relationship.

Authors and co-cited authors

Among all authors who have published literature related to rupture risk factors for IAs, Table 5 lists the top 10 authors with the most publications. The top 10 authors have collectively published 397 papers, accounting for 9.65% of all papers in this field. Rinkel Gabriel JE has the greatest number of research papers, with 73 publications, followed by Xin-Jian Yang (47 papers), Koivisto Timo (40 papers), and Jaaskelainen Juha E (37 papers). Further analysis revealed that among the top ten authors, 4 were from China, 3 were from the Netherlands, 2 were from Finland, and 1 was from the United States. CiteSpace visualizes the network between authors (Figure 8).

Figure 8  The network map of co-authors in rupture risk factors of intracranial aneurysms research.

Table 5 The top 10 authors and co-cited authors related with rupture risk factors of intracranial aneurysms research.

Rank	Author	Count	Location	Co-cited author	Citation
1	Rinkel Gabriel JE	73	Netherlands	Wiebers D	795
2	Xin-Jian Yang	47	China	Juvela S	766
3	Koivisto Timo	40	Finland	Vlak Mhm	536
4	Jaaskelainen Juha E	37	Finland	Rinkel Gje	429
5	Du Rose	36	United States	Morita A	428
6	Shuo Wang	36	China	Greving JP	357
7	You-Xiang Li	34	China	Chalouhi N	354
8	Hernesniemi Juha	32	China	Brinjikji W	353
9	Ruigrok Ynte M	32	Netherlands	Schievink WI	335
10	Algra Ale	30	Netherlands	Inagawa T	333

Figure 9A and Table 5 display the top 10 authors with the most co-citations and citations, respectively. A total of 54 authors have been cited more than 20 times, indicating that their research has a strong reputation and strong influence. The largest nodes are associated with the authors who have the most co-citations, including Wiebers D (795 citations), Juvela S (766 citations), and Vlak MHM (536 citations).

Figure 9 Density map of co-cited authors and co-cited references in rupture risk factors of intracranial aneurysms research. A: Density map of co-cited authors in rupture risk factors of intracranial aneurysms research; B: Density map of co-cited references in rupture risk factors of intracranial aneurysms research.

Co-cited references

Based on the top 10 co-cited articles (Table 6), one of them included “Development of the PHASES score for prediction of risk of rupture of IAs: A pooled analysis of six prospective cohort studies” from Lancet Neurology. The primary author of this article is Jacoba P Greving. He found that the PHASES score serves as a readily applicable tool for predicting the rupture risk of asymptomatic IAs[5]. Within the temporal scope spanning from 2004 to 2023, represented in annual time slices, the co-citation network of references comprises 678 nodes and 2377 links (Figure 9B). Ranked second is “The natural course of unruptured cerebral aneurysms in a Japanese cohort” published in the New England Journal of Medicine of Medicine. The authors of this article are UCAS Japan Investigators. Their study demonstrated that the natural progression of unruptured cerebral aneurysms is influenced by factors such as aneurysm size, location, and morphology[18].

Table 6 The top 10 co-cited references related to rupture risk factors of intracranial aneurysms research.

Rank	Title	Journal	Author(s)	Total citations
1	Development of the PHASES score for prediction of risk of rupture of intracranial aneurysms: a pooled analysis of six prospective cohort studies	Lancet Neurology	Greving JP	150
2	The natural course of unruptured cerebral aneurysms in a Japanese cohort	New England Journal of Medicine	Morita A	135
3	Prevalence of unruptured intracranial aneurysms, with emphasis on sex, age, comorbidity, country, and time period: a systematic review and meta-analysis	Lancet Neurology	Vlak MHM	110
4	Guidelines for the management of patients with unruptured intracranial aneurysms a guideline for healthcare professionals From the American Heart Association/American Stroke Association	Stroke	Thompson BG	100
5	Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture (reprinted from Journal of Neurosurgery, vol 93, pg 379-387, 2000)	Journal of Neurosurgery	Juvela S	83
6	High WSS or low WSS? Complex interactions of hemodynamics with intracranial aneurysm initiation, growth, and rupture: Toward a unifying hypothesis	American Journal of Neuroradiology	Meng H	78
7	Guidelines for the management of aneurysmal subarachnoid hemorrhage a guideline for healthcare professionals From the American Heart Association/American Stroke Association	Stroke	Connolly ES	78
8	Worldwide incidence of aneurysmal subarachnoid hemorrhage according to region, time period, blood pressure, and smoking prevalence in the population a systematic review and meta-analysis	Jama Neurology	Etminan N	73
9	Natural history of unruptured intracranial aneurysms a long-term follow-up study	Stroke	Juvela S	72
10	Risk factors for growth of intracranial aneurysms: A systematic review and meta-analysis	American Journal of Neuroradiology	Brinjikji W	70

We conducted co-citation reference clustering and temporal clustering analysis (Figures 10 and 11). Our findings revealed that endovascular therapy (cluster 1), polymorphisms (cluster 8), and patent foramen ovale (cluster 10) were early research hotspots. In the mid-term, microarray analysis (cluster 2), wall shear stress (cluster 4), hydrocephalus (cluster 7), vertebral artery (cluster 11), patent foramen ovale (cluster 12), subarachnoid hemorrhage (cluster 14), and HDAC inhibitors (cluster 13) emerged as prominent research areas. Magnetic resonance imaging (cluster 0), risk factor (cluster 3), flow diverter (cluster 5), radiosurgery (cluster 6), aneurysmal subarachnoid hemorrhage (cluster 9), and the ellipticity index (cluster 13) represent the current hot topics and trends in this field.

Figure 10  Co-citation Clustered network of the rupture risk factors for intracranial aneurysms research.

Figure 11  Volcano map of the co-citation related to the rupture risk factors for intracranial aneurysms.

Keywords and references with citation burstness

By analyzing keywords, we can swiftly grasp the status and developmental trajectory of a particular field. Based on the co-occurrence of keywords in VOSviewer, the most prominent term was “subarachnoid hemorrhage” (1286 occurrences), followed by “rupture” (594), “management” (563), “natural history” (475), and “stroke” (458) (Table 7, Figures 12 and 13). After filtering out irrelevant keywords, we constructed a network comprising 170 keywords that appeared at least 33 times, yielding 5 distinct clusters. The first cluster (in red) encompasses 45 keywords, including “rupture”, “natural history”, “prediction”, “flow”, “morphology”, “aspect ratio”, “geometry”, “location”, “artery”, “CT angiography”, “geometry”, “magnetic resonance imaging”, “MRI”, “score”, “shape”, “hemodynamics”, “cohort”, and “parameters”. The second cluster (in green) comprised 39 keywords, such as “endovascular treatment”, “safety”, “follow-up”, “morbidity”, “surgery”, “therapy”, “embolization”, “recurrence”, “clipping”, “long term”, “stent”, “neurosurgery”, “efficacy”, “occlusion”, “trial”, “flow diversion”, and “recanalization”. The third cluster (in blue) included 36 keywords, such as “subarachnoid hemorrhage”, “association”, “population”, “region”, “age”, “case fatality”, “cigarette smoking”, “disease”, “emphasis”, “epidemiology”, “gender”, “genetics”, “hypertension”, “meta-analysis”, “population”, “sex”, and “time”. The fourth cluster (in yellow) consisted of 27 keywords, such as “brain”, “aneurysms”, “children”, “diagnosis”, “dissection”, “events”, “headache”, “hemorrhage”, “ischemic stroke”, “prevention”, “repair”, “replacement”, and “vertebral artery”. The fifth cluster (in purple) contains 23 keywords, including “blood”, “cerebral infarction”, “outcome”, “impact”, “predictors”, “scale”, “vasospasm”, “infarction”, “prognosis”, “delayed cerebral ischemia”, “infarction”, “rebleeding”, “vasospasm”, “quality of life”, “hydrocephalus”, and “symptomatic vasospasm”. We generated a volcano plot using CiteSpace to visually depict the evolution of research hotspots over time (Figures 14 and 15).

Figure 12  The co-occurrence network and clusters of keywords related to rupture risk factors of intracranial aneurysms research.

Figure 13  Density map of keywords in rupture risk factors of intracranial aneurysms research.

Figure 14  CiteSpace visualization keywords volcano map of timeline viewer related to the rupture risk factors for intracranial aneurysms.

Figure 15  Keywords cluster graph of timeline viewer related to the rupture risk factors for intracranial aneurysms.

Table 7 The top 20 keywords concerning rupture risk factors of intracranial aneurysms research.

Rank	Keyword	Counts
1	Subarachnoid hemorrhage	1286
2	Rupture	594
3	Management	563
4	Natural-history	475
5	Stroke	458
6	Endovascular treatment	422
7	Surgery	281
8	Complications	263
9	Prevalence	240
10	Hemodynamics	222
11	Embolization	220
12	Mortality	220
13	Growth	216
14	Outcome	203
15	Aneurysms	200
16	Coiling	199
17	Angiography	195
18	Vasospasm	189
19	Age	179
20	Follow-up	171

Through CiteSpace, we identified the 50 most reliable citation bursts in the field of rupture risk factors for IAs. The most highly cited reference (with a burst rate of 51.74) is the article titled “The natural course of unruptured cerebral aneurysms in a Japanese cohort” published in the New England Journal of Medicine, with the first author being The UCAS Japan Investigators. Out of the 50 references, 47 were published between 2004 and 2023, indicating that these papers have been frequently cited over the past two decades. Importantly, 8 of these papers are currently experiencing a peak in citations (as shown in Figure 16), suggesting that the rupture risk factors for IAs will continue to be a subject of interest in the future. Among the 844 most prominent burst keywords in this field, we have specifically focused on the top 50 keywords with the most intense bursts (as depicted in Figure 17). These keywords represent the current research hotspots in the field and indicate potential directions for future studies.

Figure 16  Representative burst references with the top 50 strongest citation.

Figure 17  Representative burst keywords among top 50 references with the strongest citation bursts.

DISCUSSION

General information

In this investigation, a bibliometric analysis was performed on publications pertaining to risk factors associated with IA rupture over the past two decades. The aim was to discern prominent areas of focus and emerging trends in this research domain. Our findings reveal a notable surge in the volume of publications concerning risk factors for IA rupture, particularly since 2012, with a pinnacle observed in 2023. This upward trajectory underscores the sustained relevance and continued interest of researchers in this field for the foreseeable future.

Our analysis revealed that the United States plays a pivotal role in research on risk factors for IA rupture, with significant contributions from China, Japan, Germany, and South Korea. Approximately 28.97% of all publications originated from researchers in the United States. Notably, the United States exhibited dominance in publication output, total citations, and international collaborations based on our findings. The notable performance of the Netherlands and Canada in total citations underscores the quality of research activities in these nations. In terms of international cooperation, the United States, Italy, and Germany were identified as closely collaborating with other countries, while China, Japan, South Korea, and the Netherlands engaged in collaboration to a lesser extent, potentially impacting their citation rankings. Strengthening international collaboration in China, Japan, South Korea, and the Netherlands is essential for enhancing the dissemination of high-quality publications.

Among the top 10 institutions with the greatest impact, 40% were located in the United States. Notably, Capital Medical University in China had the highest volume of publications but was ranked ninth in overall citations. This suggests that the institution should focus on enhancing research quality and fostering increased collaboration and knowledge exchange. Among the authors, Gabriel JE, Xin-Jian Yang, Timo Koivisto, and Juha E. Jaaskelainen stood out for their significant contributions to advancing the understanding of risk factors associated with the rupture of IAs. Furthermore, works by Wiebers D, Juvela S, and Vlak MHM received the highest average number of citations, underscoring the caliber of their research contributions in this domain. Our analysis revealed that several journals are actively publishing research on the risk factors for IA rupture. Noteworthy publications in this area appeared in World Neurosurgery, Journal of Neurosurgery, Stroke, and Neurosurgery, indicating that these journals are primary outlets for disseminating research findings in this field.

Knowledge base

Co-cited references indicate the frequency with which two publications are jointly cited by other works, serving as a knowledge repository within a specific field[19]. In this scientometric analysis, the top 10 co-cited references were examined to delineate the foundational knowledge base concerning risk factors for IA rupture. The study by Greving et al[5] was the most frequently cited publication in 2014, garnering 150 co-citations. This article elucidates the utility of the PHASES score in predicting the risk of IA rupture by considering factors such as age, hypertension, aneurysm size, and location, highlighting variations in rupture risk among diverse populations. The second most highly cited publication, the New England Journal of Medicine, was authored by UCAS Japan Investigator[18]. This study demonstrated that the natural progression of unruptured cerebral aneurysms varies based on factors such as the size, location, and shape of the aneurysm. In 2011, Vlak et al[2] published the third co-cited paper in Lancet Neurology. This study revealed that the increased incidence of subarachnoid hemorrhage in Finland and Japan could not be solely attributed to a greater incidence of UIAs, indicating an elevated risk of rupture in these populations. Stroke published the fourth co-cited prospective study by Thompson et al[20]. The objective of this guideline is to offer thorough and evidence-based recommendations for the management of patients with UIAs. A holistic approach involving both risk factor prevention and management may be essential to decrease the prevalence of unruptured aneurysms and their potential as a precursor for subarachnoid hemorrhage in the majority of cases. The fifth co-cited publication was published in the Journal of Neurosurgery by Juvela et al[21]. The study highlighted that cigarette smoking, the size of the UIA, and age (inversely) are significant factors that influence the risk of subsequent aneurysm rupture. The sixth co-cited study was published in 2014 by Meng et al[22]. This study suggested that low wall shear stress and a high oscillatory shear index play a role in activating an inflammatory cell-mediated pathway that could contribute to the formation and rupture of large atherosclerotic aneurysms. Conversely, high wall shear stress combined with a positive wall shear stress gradient is linked to a mural cell-mediated pathway, which may lead to the expansion and rupture of small or secondary bleb aneurysms. The seventh most commonly co-cited paper was published by Connolly et al[23] in Stroke. The guidelines concluded that, beyond the size and location of the aneurysm and the patient’s age and health status, it may be appropriate to take into account the morphological and hemodynamic features of the aneurysm when assessing the risk of aneurysm rupture. In 2019, the eighth most commonly co-cited paper was published by Etminan et al[24] in JAMA Neurology. In their systematic review and meta-analysis, the researchers found that the global incidence of subarachnoid hemorrhage and its decline exhibit significant regional variations, closely mirroring the reduction in blood pressure and smoking rates. Identifying the factors contributing to these regional differences and implementing strategies to further reduce blood pressure and smoking prevalence could lead to a reduction in the overall burden of subarachnoid hemorrhage. Juvela et al[25] investigated the long-term natural history of UIAs and risk factors predictive of subsequent rupture and published the ninth co-cited paper. Cigarette smoking, patient age (inversely), and the size and location of the UIA appear to be risk factors for aneurysm rupture. However, the risk of bleeding tends to decrease with very long-term follow-up. The article published in the American Journal of Neuroradiology in 2016, which received the last co-citations, presented observational evidence highlighting various clinical and anatomic risk factors for aneurysm growth. These factors included age over 50 years, female sex, smoking history, and nonsaccular shape. These findings should be taken into account when advising patients about the natural progression of UIA[26]. In general, the top 10 co-citations primarily focused on clinical, morphological, and hemodynamic risk factors, as well as the development of a simple and practical scoring system to assess the risk of rupture factors for IAs. These foundational topics have significantly contributed to advancements in this field of study.

Emerging topics

Keywords play a crucial role in reflecting the prevailing research themes and trajectories within a specific domain. Table 7 highlights the prominence of the top 20 keywords, each appearing more than 170 times, which encapsulates the pivotal areas of investigation concerning the risk factors associated with IA rupture. Noteworthy keywords include subarachnoid hemorrhage, rupture, management, natural history, stroke, endovascular treatment, surgery, complications, prevalence, and hemodynamics. These keywords collectively paint a comprehensive picture of the landscape surrounding risk factors for IA rupture. Specifically, they underscore: (1) The critical association between IA rupture and subarachnoid hemorrhage, a significant contributor to stroke[27-30]; (2) The intrinsic link between the natural history of IAs and their propensity for rupture[27,29,31]; (3) The increasing interest in hemodynamic parameters concerning IAs in recent studies[32-35]; and (4) The pivotal role of understanding risk factors for IA rupture in enhancing management and treatment strategies aimed at averting complications, encompassing both surgical and endovascular interventions[23,36-38].

The keyword density map serves as a visual representation, offering a more intuitive depiction of the prevalent keywords within this field (Figure 13). Through network clustering analysis, the keywords are categorized into five clusters, effectively delineating the research focus and breadth of this domain. As illustrated in Figure 12, these clusters are as follows: Cluster 1 (red) predominantly explores the natural history and hemodynamic risk factors associated with IA rupture. Cluster 2 (green) centers on endovascular and surgical interventions for IA treatment. Cluster 3 (blue) includes 2 epidemiological and genetic risk factors pertinent to IAs. Cluster 4 (yellow) focuses on the complications arising from IA rupture. Cluster 5 (purple) is dedicated to investigating the impact and prognosis of IA rupture. These five clusters represent the research focus and scope of IA rupture risk factor research to some extent. In addition, from this ranking, we can see that IA rupture research on natural history and hemodynamic risk factors has become a critical research focus. Only by gaining a profound understanding of the pivotal factors contributing to IA rupture can we fundamentally discern effective therapeutic modalities for the management of IAs, thereby mitigating the occurrence of rupture-related complications, reducing disability rates, and lowering mortality rates. The timeline viewer (Figure 14) for keywords enables us to discern the temporal progression of topics within this domain, facilitating an exploration of the evolutionary trajectory of this field.

References experiencing intense citation bursts denote a sudden surge in citations for specific documents within a defined timeframe. This phenomenon aids in identifying emerging topics and research areas that have garnered significant attention within a particular field[12]. This study identified the most impactful citation bursts and curated the top 50 among them (Figure 16). The paper (strength: 51.74) with the strongest citation burstness was a large, prospective cohort study published by UCAS Japan Investigators[18] in the New England Journal of Medicine in 2012. This study in Japan from 2001 to 2004 examined 6697 UIAs, 91% of which were incidentally discovered, predominantly in the middle cerebral and internal carotid arteries. Research has shown that the risk of aneurysm rupture increases with size, with larger aneurysms and those in the posterior and anterior communicating arteries being more likely to rupture. Overall, the study highlighted the diverse natural history of UIAs based on size, location, and shape. Currently, 8 (16%) of the top 50 papers are still in a state of citation burst, and the citation burst of 7 papers has lasted for at least 3 years. These 7 papers represent the latest research topics related to rupture risk factors for IAs. According to the ranking by burst strength (from high to low), paper No. 1 (strength: 51.47) is mentioned above. The second-ranked paper (strength: 45.31) was published by Vlak et al[2] in Lancet Neurology in 2011. Researchers have shown that the prevalence of UIAs is greater in patients with autosomal dominant polycystic kidney disease or a positive family history of IAs or subarachnoid hemorrhage than in individuals without these comorbidities. In Finland and Japan, the increased incidence of subarachnoid hemorrhage cannot be solely accounted for by a higher incidence of UIAs, suggesting an elevated risk of aneurysm rupture. The third-ranked paper (strength: 43.49) was published by Greving et al[5] in Lancet Neurology in 2014. They conducted a systematic review and pooled analysis of individual patient data from 8382 participants across six prospective cohort studies focusing on subarachnoid hemorrhage as the primary outcome. The objective of this study was to identify predictors of aneurysm rupture in individuals with UIAs and to develop a risk prediction tool enabling healthcare providers to assess the 5-year risk of aneurysm rupture based on routinely evaluated patient and aneurysm features. The study concluded that the PHASES score serves as a user-friendly tool for predicting the risk of rupture in asymptomatic IAs. The fourth-ranked paper (strength: 34.43) was published by Thompson et al[20] in Stroke in 2015. The writing group members conducted systematic literature reviews spanning from January 1977 to June 2014. Additionally, they examined current evidence-based guidelines to offer thorough and evidence-supported recommendations for the management of individuals with UIAs. Finally, Juvela et al[21] published the article with the fifth-highest citation burst (strength: 33.43) in the Journal of Neurosurgery in 2000. The study revealed that cigarette smoking, the size of the UIA, and age (inversely) are crucial factors that influence the risk of future aneurysm rupture. The authors recommend surgical intervention for such unruptured aneurysms irrespective of their size and the patient’s smoking habits, particularly in younger and middle-aged adults, provided that this approach is feasible and that the patient’s comorbidities are not contraindicated. For older patients with small aneurysms, smoking cessation could be considered a viable alternative to surgery. The citation burstness analysis showed that exploring the different risk factors for IA rupture (such as age, smoking status, and hemodynamic parameters) and advocating for proactive surgical interventions (including both surgical procedures and endovascular treatments) are essential for mitigating the potential risk of IA rupture.

Limitations

First, the data were exclusively sourced from the WoSCC, as opposed to conducting searches across additional databases such as Embase or Scopus. While the WoSCC serves as a widely utilized and extensive online database within the realm of scientometrics[39-41], it is plausible that numerous papers pertaining to this subject have been published in journals that are not encompassed within the Web of Science. Second, the present scientometric instruments encounter significant challenges in concurrently analyzing data from multiple databases. Subsequently, all data were extracted using scientometric tools rather than being manually curated by authors in meta-analyses or systematic review overviews[41-43]. Third, the exclusion of non-English publications meant that seminal articles published in languages other than English were not considered, leading to a limited number of articles being omitted from the analysis. Finally, potential biases may be inherent in our findings. For instance, the likelihood of author homonymy remains a concern, as these tools may not accurately discern such nuances. These issues could be addressed in the future through advancements in machine learning, natural language processing, and data science[44]. Nonetheless, our findings are largely congruent with the conclusions drawn from the most recent traditional literature reviews while simultaneously providing scholars with more objective data, knowledge, and insights.

CONCLUSION

We used CiteSpace and VOSviewer to analyze the knowledge base and research hotspots on rupture risk factors for IA publications in the past decade. The United States contributed the most to IA risk factor-related research, and the Capital Medical University produced the most publications. Worldwide, Neurosurgery and Stroke were the most significant journals for determining the risk factors for IA rupture. Rinkel Gabriel JE and Wiebers D may have an important influence on this field because they published numerous articles and were co-cited in several more publications. Exploring the hemodynamic features and emphasizing the importance of preventing IA rupture were recent topics of interest in this research. This scientometric review offers a comprehensive understanding of drug-induced liver injury-related publications from 2004 to 2023, which could serve as a reference for researchers in this field. As investigators discover more information on rupture risk factors for IAs, we look forward to more targeted treatments and preventive measures to reduce the burden of IAs.