Neuroimaging diagnosis for cerebral infarction An 8-year bibliometric analysis

Abstract

Objective: To identify global research trends in neuroimaging diagnosis for cerebral infarction using a bibliometric analysis of the Web of Science. Data Retrieval: We performed a bibliometric analysis of data retrieval for neuroimaging diagnosis for cerebral infarction containing the key words "CT, magnetic resonance imaging, MRI, transcranial Doppler, transvaginal color Doppler, digital subtraction angiography, and cerebral infarction" using the Web of Science. Selection Criteria: Inclusion criteria were: (a) peer-reviewed articles on neuroimaging diagnosis for cerebral infarction which were published and indexed in the Web of Science; (b) original research articles and reviews; and (c) publication between 2004-2011. Exclusion criteria were: (a) articles that required manual searching or telephone access; and (b) corrected papers or book chapters. Main Outcome Measures: (1) Annual publication output; (2) distribution according to country; (3) distribution according to institution; (4) top cited publications; (5) distribution according to journals; and (6) comparison of study results on neuroimaging diagnosis for cerebral infarction. Results: Imaging has become the predominant method used in diagnosing cerebral infarction. The most frequently used clinical imaging methods were digital subtraction angiography, CT, MRI, and transcranial color Doppler examination. Digital subtraction angiography is used as the gold standard. However, it is a costly and time-consuming invasive diagnosis that requires some radiation exposure, and is poorly accepted by patients. As such, it is mostly adopted in interventional therapy in the clinic. CT is now accepted as a rapid, simple, and reliable non-invasive method for use in diagnosis of cerebrovascular disease and preoperative appraisal. Ultrasonic Doppler can be used to reflect the hardness of the vascular wall and the nature of the plaque more clearly than CT and MRI. Conclusion: At present, there is no unified standard of classification of cerebral infarction imaging. Detection of clinical super-acute cerebral infarction remains controversial due to its changes on imaging, lack of specificity, and its similarity to a space-occupying lesion. Neuroimaging diagnosis for cerebral infarction remains a highly active area of research and development. Research Highlights

1. We performed a bibliometric analysis of data retrieval for neuroimaging diagnosis for cerebral infarction from 2004 to 2011 using the Web of Science.
2. We analyzed the articles by annual publication output, distribution according to country, distribution according to institution, top cited publications, and distribution according to journals, and made a comparison of study results on neuroimaging diagnosis for cerebral infarction.
3. We found that neuroimaging diagnosis for cerebral infarction remains an area of active research. Chinese radiologists should be encouraged to write more high-quality papers to participate in and enlarge academic exchange worldwide.

Abbreviations DSA, digital subtraction angiography; TCD, transcranial Doppler

Introduction

Cerebral infarction is one of the most common clinical cerebrovascular diseases, and accounts for 60-80% of cerebrovascular disorders. Cerebral infarction is the second leading cause of death due to its acute progress, quick deterioration, and serious complications of cerebral edema[1]. The most effective methods for its treatment include thrombolytic therapy at the early stage and individualized treatment at the acute phase. Traditional diagnostic methods typically depend on neural morphology. Although of the majority of cerebral infarction patients exhibit a specific clinical manifestation of neurologic defects, some patients are asymptomatic, termed silent cerebral infarction. These patients only exhibit nonspecific clinical manifestations such as dizziness, headache, and vertigo instead of any neurologic defect, and can only be diagnosed by CT or MRI[2]. The development of modern medical techniques and imaging technology, especially the progress of CT and MRI, has progressed diagnosis from traditional morphology to the combination of morphology and function[3]. Despite this improvement of imaging diagnosis accuracy, it remains difficult to correctly diagnose in the early phase.

Imaging is currently the most reliable policy used in treatment of cerebral infarction. The most common clinical imaging technique was digital subtraction angiography (DSA), followed by CT, MRI, and transcranial color Doppler examination. DSA serves as the gold standard for diagnosis of cerebrovascular disorders, and has a high spatial resolution and provides dynamic vessel flow[4]. Nevertheless, DSA is a costly and time-consuming invasive diagnosis that requires some radiation exposure, and is poorly accepted by patients. As such, it is predominantly adopted in clinical interventional therapy. It is now accepted that CT is a rapid, simple, and reliable non-invasive method in diagnosing cerebral disease, and is one of the latest technologies used for diagnosis of cerebral vessels and preoperative appraisal. As well as cerebral infarct images, CT possesses a special vertical view, which can direct and project the operative route. In particular, multimodal CT examination has improved the accuracy and high spatial resolution of CT, and is a significant predictor in the prognosis of cerebral infarction. CT has a higher specificity than MRI, although its sensitivity to cerebral infarction in the early stage is lower[5]. MRI, especially diffusion weighted MRI, has a higher sensitivity to cerebral infarction, although its feasibility in emergency treatment is lower than CT as it has more contraindications[6]. Ultrasonic Doppler is an ultrasound examination involving a combination of transcranial Doppler (TCD) and transcranial color-code Doppler. The advantages of ultrasonic Doppler include its noninvasive and dynamic imaging of vessel flow, ease of operation, and strong repeatability, and it can reflect the hardness of the vascular wall and the nature of the plaque more clearly than CT and MRI. However, ultrasonic Doppler lacks sensitivity in judging stenosis and occlusion.

At present, there is no unified standard of classification of cerebral infarction imaging[7]. Detection of clinical super-acute cerebral infarction remains controversial because of its changes on imaging, lack of specificity, and its similarity to a space-occupying lesion[8]. The most effective way to treat cerebral infarction patients is through diagnosis in the early stage and the development of correct methods. Although imaging is the most efficient method for diagnosis and prediction in the early phase, there are limited related data for cerebral infarction imaging, particularly with respect to new imaging techniques such as arterial spin labeling and arterial spin labeling of endogenous tracer. Future studies are required to verify the use of imaging in diagnosis of cerebral infarction.

Data Sources and Methodology

Data retrieval

In this study, we used bibliometric methods to quantitatively and qualitatively investigate research trends in studies of neuroimaging diagnosis for cerebral infarction. Web of Science, a research database of publications and citations that are selected and evaluated by the Institute for Scientific Information in Philadelphia, PA, USA, using the key words computed tomography, CT, magnetic resonance imaging, MRI, TransCranial Doppler, transvaginal color doppler, digital subtraction angiography, and cerebral infarction. We have limited the period of publication from 2004 to 2011, and downloaded the data on July 02, 2012.

Inclusion criteria

(a) Peer-reviewed articles on neuroimaging diagnosis for cerebral infarction which were published and indexed in the Web of Science; (b) type of articles: original research articles and reviews; (c) year of publication: 2004-2011.

Exclusion criteria

(a) Articles that required manual searching or telephone access; (b) we excluded a number of corrected papers or book chapters from the total number of articles.

The searching results were analyzed by (1) annual publication output; (2) distribution according to country; (3) distribution according to institution; (4) top cited publications; (5) distribution according to journals; and (6) comparison of study results on neuroimaging diagnosis for cerebral infarction.

Results

Search results of publications addressing neuroimaging diagnosis for cerebral infarction from 2004 to 2011 [Table 1]{Table 1}

Annual publication output of CT diagnosis for cerebral infarction from 2004 to 2011 [Figure 1]{Figure 1}

There were 461 publications on CT diagnosis for cerebral infarction in the Web of Science from 2004 to 2011. The number of publications on CT diagnosis for cerebral infarction has keeps stable between 2004 and 2011. The publication on CT diagnosis for cerebral infarction reached a peak in 2009. However, there are a number of years which saw slightly drops in the number of paper.

Publication distribution of countries and institutes based on CT diagnosis for cerebral infarction from 2004 to 2011 [Table 2], [Table 3]{Table 2}{Table 3}

The contribution analysis of different countries for publications was based on journal articles in which the address and affiliation of at least one author were provided. The total number of articles analyzed by country and institute publications was 461.

From [Table 2], it can be seen that Japan published the most papers on CT diagnosis for cerebral infarction. Japan published 103 papers that accounted for 22.34% of the total, which was much higher than the number of publications by other countries. USA ranked second with 74 papers that accounted for 16.05%.

Results from [Table 3] showed that Columbia University, University of Edinburgh and Massachusetts General Hospital were the most prolific research institutes for publications on CT diagnosis for cerebral infarction. Among the top eight research institutes publishing in this field, four are in the USA, and the other four are respectively in the UK, China, Germany and Finland.

Journals that published on CT diagnosis for cerebral infarction from 2004 to 2011

It is evident that most papers on CT diagnosis for cerebral infarction appeared in journals with a particular focus on neuroscience. Stroke published 45 papers that accounted for 9.76% of the total number of publications, which was followed by Cerebrovascular Diseases that published 26 papers and accounted for 5.64% [Table 4].{Table 4}

Annual publication output of MRI diagnosis for cerebral infarction from 2004 to 2011 [Figure 2]{Figure 2}

There were 642 publications on MRI diagnosis for cerebral infarction in the Web of Science from 2004 to 2011. The number of publications on MRI diagnosis for cerebral infarction has gradually increased over the past 8 years.

Publication distribution of countries and institutes based on MRI diagnosis for cerebral infarction from 2004 to 2011 [Table 5], [Table 6]{Table 5}{Table 6}

The contribution analysis of different countries for publications was based on journal articles in which the address and affiliation of at least one author were provided. The total number of articles analyzed by country and institute publications was 461.

From [Table 5], it can be seen that Japan published the most papers on MRI diagnosis for cerebral infarction. Japan published 175 papers that accounted for 27.26% of the total, which was much higher than the number of publications by other countries. USA ranked second with 121 papers that accounted for 18.85%.

From [Table 6], it can be seen that Harvard University, Tohoku University and Sun Yat-sen University were the three most prolific research institutes for publications on MRI diagnosis for cerebral infarction. Among the top seven research institutes publishing in this field, only one institution from China.

The most-cited papers included in the Web of Science from 2004 to 2011 by Chinese authors were:

Cerebral Infarcts complicating tuberculous meningitis[9], by Chan et al, published in Cerebrovascular Diseases in 2005, with 30 citations.

Surgery for acute type A dissection using total arch replacement combined with stented elephant trunk implantation: Experience with 107 patients[10], by Sun et al, published in Journal of Thoracic and Cardiovascular Surgery in 2009, with 20 citations.

Diagnostic value of single-photon-emission computed tomography in severe central nervous system involvement of systemic lupus erythematosus: A case-control study[11], by Zhang et al, published in Arthritis & Rheumatism-Arthritis Care & Research in 2005, with 17 citations.

Association of apolipoprotein E 4 polymorphism with cerebral infarction in Chinese Han population[12], by Jin et al, published in Acta Pharmacologica Sinica in 2004, with 17 citations.

CT and MR findings in HIV-negative neurosyphilis[13], by Peng et al, published in European Journal of Radiology in 2008, with 10 citations.

Journals that published on MRI diagnosis for cerebral infarction from 2004 to 2011

It is evident that most papers on MRI diagnosis for cerebral infarction appeared in journals with a particular focus on neuroscience. Stroke published 58 papers that accounted for 9.03% of the total number of publications, which was followed by Cerebrovascular Diseases which published 28 papers and accounted for 4.36% [Table 7].{Table 7}

Most cited articles on MRI diagnosis for cerebral infarction from 2004 to 2011

According to bibliometric "law", the main index for evaluating the quality of an article is the amount of citations it garners. Scientometrics has shown that references are considered as "classical references" once an article is cited four or more times[14]. In our analysis, the top nine citations are listed in [Table 8]; therefore, they are classical references in the neuroimaging diagnosis for cerebral infarction field [Table 8]{Table 8}

Annual publication output of TCD diagnosis for cerebral infarction from 2004 to 2011

There were 98 publications on TCD diagnosis for cerebral infarction in the Web of Science from 2004 to 2011. There were 11 papers on TCD diagnosis for cerebral infarction in 2004, and then it down to the valley in 2005, gradually increased in 2006, reached a peak in 2007, and then reached a balance [Figure 3].{Figure 3}

Journals that published on TCD diagnosis for cerebral infarction from 2004 to 2011 [Table 9]

Publication distribution of countries based on TCD diagnosis for cerebral infarction from 2004 to 2011

The contribution analysis of different countries/territories for publications was based on journal articles in which the address and affiliation of at least one author were provided. The total number of articles analyzed for country and institute publications was 98. The top nine countries/territories were then ranked.

In [Table 9], it is clear that the USA published the most papers on TCD diagnosis for cerebral infarction, with 28 papers that accounted for 28.57% of the total, which was much higher than the number of papers published by other countries. Germany ranked second with 14 papers that accounted for 14.29%.

In [Table 10], it is evident that Stroke published 10 papers that accounted for 10.20% of the total number of publications, which was followed by Neurocritical Care which published six papers and accounted for 6.12%.{Table 9}{Table 10}

Most cited articles on TCD diagnosis for cerebral infarction from 2004 to 2011 [Table 11]{Table 11}

Discussion

Based on our bibliometric results from the Web of Science, we found the following research trends in studies on neuroimaging diagnosis for cerebral infarction over the past eight years. There were 461 research articles addressing CT diagnosis for cerebral infarction included in the Web of Science, 642 articles concerning MRI diagnosis for cerebral infarction, 98 articles about TCD diagnosis for cerebral infarction and only 25 papers on DSA diagnosis for cerebral infarction. It is found that MRI and CT are commonly adopted imaging methods in the diagnosing cerebral infarction.

The Japan published the most papers on CT and MRI diagnosis for cerebral infarction, followed by USA. However, it is USA which published most papers on TCD diagnosis for cerebral infarction rather than Japan, followed by Germany and France. Though China is in the list of top ten countries in publishing articles, it is disappointing that it only published fewer articles than other countries. Columbia University, University of Edinburgh and Massachusetts General Hospital were the most prolific research institutes for publications on CT diagnosis for cerebral infarction. Among the top eight research institutes publishing in this field, four are in the USA, each one in UK, China, Germany and Finland.

As to MRI diagnosis for cerebral infarction, Harvard University, Tohoku University and Sun Yat-sen University were the three most prolific research institutes.

Research interests including stroke, clinical neurology, as well as radiology are involved in neuroimaging diagnosis for cerebral infarction studies. Most researchers are focused on CT and MRI methods for diagnosing cerebral infarction, and fewer on DSA. Though DSA has resulted in major advances in cerebral infarction diagnosis in China, there are only five articles by Chinese authors that can be found in the Web of Science. This suggests that Chinese investigators should improve their writing and communication skills as well as increase the number of publications and preferred conference abstracts in order to contribute to and enlarge worldwide academic exchange in the field of neuroimaging diagnosis for cerebral infarction.[32]