|Year : 2018 | Volume
| Issue : 18 | Page : 2246-2248
Multimodal Magnetic Resonance Imaging Studies of Migraines Related to Increasing Risk Factors for Brain Lesions Would Be an Optimal Research Focus: A Pilot Literature Citation Analysis
Meng-Qi Liu1, Zhi-Ye Chen2, Sheng-Yuan Yu3, Lin Ma4
1 Department of Radiology, Chinese People's Liberation Army General Hospital; Department of Radiology, Haninan Branch of Chinese People's Liberation Army General Hospital, Beijing 100853, China
2 Department of Radiology, Chinese People's Liberation Army General Hospital; Department of Radiology, Haninan Branch of Chinese People's Liberation Army General Hospital, Beijing 100853, China; Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
3 Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
4 Department of Radiology, Chinese People's Liberation Army General Hospital, Beijing 100853, China
|Date of Submission||23-Apr-2018|
|Date of Web Publication||10-Sep-2018|
Prof. Lin Ma
Department of Radiology, Chinese People's Liberation Army General Hospital, Beijing 100853
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Liu MQ, Chen ZY, Yu SY, Ma L. Multimodal Magnetic Resonance Imaging Studies of Migraines Related to Increasing Risk Factors for Brain Lesions Would Be an Optimal Research Focus: A Pilot Literature Citation Analysis. Chin Med J 2018;131:2246-8
|How to cite this URL:|
Liu MQ, Chen ZY, Yu SY, Ma L. Multimodal Magnetic Resonance Imaging Studies of Migraines Related to Increasing Risk Factors for Brain Lesions Would Be an Optimal Research Focus: A Pilot Literature Citation Analysis. Chin Med J [serial online] 2018 [cited 2018 Sep 19];131:2246-8. Available from: http://www.cmj.org/text.asp?2018/131/18/2246/240806
To the Editor: Migraine is the third most prevalent headache disorder and the seventh leading cause of disability worldwide. The first magnetic resonance imaging (MRI) migraine study was reported in 1995, with many subsequent MRI migraine studies appearing after the development of structural brain and functional MRIs. Advanced MRI techniques such as voxel-based morphometry, advanced brain structure segment, and resting functional MRI (fMRI) have led to significant discoveries. MRI has played a key role in the diagnosis, evaluation, and understanding of migraine neuromechanisms.
Published MRI migraine studies have provided detailed information about migraines. The current study is a literature analysis investigating the citation links of MRI migraine research.
The search strategy assessed brain changes studied using MRI in patients with migraines. The keywords used were “migraine” and “magnetic resonance imaging” according to the MESH search strategy in PubMed (https://www.ncbi.nlm.nih.gov/pubmed). The Web of Science (WOS; Core Collection, http://isiknowledge.com) database was searched for the expressions “migraine” and “magnetic resonance imaging.” The timespan included all years. The indexes included the Science Citation Index Expanded, the Conference Proceedings Citation Index-Science, the Current Chemical Reactions-Expanded, and the Index Chemicus.
All the selected documents were analyzed using HistCite (version 12.03.17, http://www.histcite.com/). The processing steps were as follows: (1) the search results were output as plain text files with full records (Recs) plus cited references (CRs); (2) the results were imported into the HistCite tool, and the analysis index included the number of Recs, local citation scores (LCSs), global citation scores (GCSs), local CRs (LCRs), CRs, total LCSs (TLCSs, the total citations in the authors' collection), and total GCSs (TGCSs, the total citations in WOS publications by the authors in the collection); and (3) a graph analysis including the backward and forward methods using the LCS index. The backward method corresponded to the citation links, and the forward method reflected the development progress.
In the current study, 840 Recs were obtained and listed as follows: 3571 authors, 302 journals, 16,822 CRs, 1920 keywords, 23 publication years (January 1, 1995, to September 14, 2017), 9 document types, 10 languages, 1109 institutions, 1872 institutions with subdivisions, and 50 countries.
According to the analysis of the LCS index, the top 10 documents are listed in [Supplementary Table 1 [Additional file 1]]. The LCS was cited 29–61 times in the current collection. Kruit's study had the highest LCS (cited 61 times). The top 10 documents with the highest LCR are listed in [Supplementary Table 2 [Additional file 2]]; Bhaska's study had the highest LCR (38 references).
The top 10 journals according to the Recs and the TLCS are listed in [Supplementary Table 3 [Additional file 3]]. The journal with the highest Recs was Cephalalgia (87 documents), and the journal with the highest TLCS was Headache (cited 335 times).
The institutional subdivision with highest Recs was Harvard University Medical School (24 documents), and the institutional subdivision with the highest TLCS was Leiden University Medical Center (cited 195 times) [Supplementary Table 4 [Additional file 4]]. The country with highest Recs and TLCS was the United States (260 documents and 667 citations, respectively) [Supplementary Table 5 [Additional file 5]].
A graph analysis using the backward method demonstrated that MRI migraine studies were classified into two subdivisions: (1) migraine as a risk factor for subclinical brain lesions from a clinical viewpoint and (2) gray matter structural changes over the whole brain in migraine from an MRI perspective [Figure 1]a. Based on the forward method, MRI migraine studies were categorized into two branches: (1) migraines related to the increasing risk of brain lesions such as deep white matter lesions, subclinical posterior circulation infarcts, and brain iron accumulation and (2) alteration of fMRI in migraines [Figure 1]b.
|Figure 1: The graph of literature citation links using the backward (a) and forward (b) methods using HistCite software. The vertical axis represents time, and the nodes are placed on the horizontal axis. Each node represents a record, and the numbers represent LCS. The size of each node is proportional to the LCS. The red and blue boxes represent two research directions corresponding to the citation links. LCS: Local citation score; fMRI: Functional magnetic resonance imaging.|
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The current research demonstrated that from 1995 to 2017, MRI migraine studies evolved from conventional MRI visual observations to advanced neuroimaging. MRI and processing techniques improved the understanding of the migraine brain. The current study referred to 840 MRI studies, 50 countries, 1109 institutions, and 3571 authors, proving that MRI plays a key role in migraine research.
All of the documents searched in this study were evaluated using LCS and GCS. LCS reflected the citation scored in the current collection, and the literature with the highest LCS was considered the most important in this research field. For example, Kruit's study had the highest LCS, demonstrating that migraine as a risk factor for subclinical brain lesions has been widely accepted. However, GCS reflected the GCS in the WOS database, but did not indicate the importance of the literature in the research field. For example, for one Rec in the current analysis, it had the highest GCS (608), while its LCS was only 2, suggesting that it was cited only two times in the current data collection (the research field). Therefore, LCS was a very important citation index.
LCR represented the local CR, referring to the number of references of the Rec in the local data collection. The document with the highest LCR value was the most important research focus and indicated the research direction. In the current study, results indicated that MRIs could be used to reveal the role of cortical spreading depression to understand the pathophysiology of migraine in future research.
Based on Recs and the TLCS analysis, it was easy to locate the submitting journal and the most important journal in the research field and to find the institution producing the best research papers and the most important institution in the research field. The top 10 journals and institutions are listed in [Supplementary Table 3] and [Supplementary Table 4]; these were the most helpful in locating the key journals and institutions in MRI migraine studies.
The graph analysis provided valuable information for research on MRI migraine studies. MRI studies from 1995 to 2017 were classified into two branches. One focused on clinical practice, which confirmed that the presence of migraines was a risk factor for subclinical brain lesions such as white matter lesions combined with conventional MRI. The other branch focused on gray matter's structural changes throughout the whole brain using advanced MRI techniques (voxel-based morphometry) in migraine patients with or without T2-visible white matter lesions. The forward method was used to assess the development progress in these two branches. The first branch developed from migraines as a risk factor to migraines related to the increasing risk of brain lesions, and the second branch developed from gray matter structural analysis to fMRI studies. Summarizing the aforementioned analysis, migraines related to increasing risk factors for brain lesions using multimodal MRI would be an appropriate focus of future research.
The graph analysis also introduced an interesting topic: the “cause or effect” relationship between migraines and subclinical brain lesions. Until recently, this was relatively difficult to assess due to the lack of diagnostic evidence. In clinical practice, migraine patients commonly undergo computed tomography (CT) examinations, and normal CT imaging findings could lead to the conclusion that migraines cause no definite brain lesions. However, MRI has a very high soft-tissue resolution and subclinical brain lesions can be clearly observed. Therefore, migraine patients should undergo MRI examinations, which might answer the aforementioned question as more MRI results are obtained and summarized.
The limits in the current study were as follows: (1) the database included only the WOS (Core Collection) because HistCite analyzed only data from the WOS, so other databases should be included for the future development of literature analysis tools; (2) only one literature analysis tool was used in this study, so other literature analysis tools should be used for comparison; and (3) other types of headaches should be included in future research.
In conclusion, the literature analysis herein assessed MRI migraine studies. Future research should focus on multimodal MRI migraine studies to elucidate if migraines increase the risk of brain lesions.
Supplementary information is linked to the online version of the paper on the Chinese Medical Journal website.
Financial support and sponsorship
This work was supported by grants from the Hainan Provincial Natural Science Foundation of China (No. 818MS153), a Special Financial Grant from the China Postdoctoral Science Foundation (No. 2014T70960), and the Foundation for Medical and Health Sciences and Tech Innovation Project of Sanya (No. 2016YW37).
Conflicts of interest
There are no conflicts of interest.
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