HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Miguel-Dasit, A. Articles by Aleixandre, R. Search for Related Content PubMed PubMed Citation Articles by Miguel-Dasit, A. Articles by Aleixandre, R.

Cardiac MR Imaging: Balanced Publication by Radiologists and Cardiologists¹

¹ From the Magnetic Resonance Section, La Plana de Vila-Real Hospital, Castellón, Spain (A.M.); Department of Radiology, Dr Peset University Hospital, Avenida Gaspar Aguilar 90, ES-46017 Valencia, Spain (L.M.); Humanities Department, Cardenal Herrera-CEU University, Alfara, Valencia, Spain (P.S.); and Institute of History of Science and Documentation Lopez Piñero, University of Valencia-CSIC, Valencia, Spain (R.A.). Received January 31, 2006; revision requested March 29; revision received April 8; final version accepted June 8. Address correspondence to L.M. (e-mail: marti_lui{at}gva.es).

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION ADVANCES IN KNOWLEDGE References

 
Purpose: To retrospectively evaluate the number of articles on cardiac magnetic resonance (MR) imaging written by authors from radiology and cardiology departments and published in Medline-indexed journals from 1999 to 2004 and the relationship between the author's specialty and various parameters.

Materials and Methods: Specific search profiles were devised to retrieve items from the Medline database. Eight hundred seven articles were included in the study. Relationships between the author's specialty (radiology or cardiology) and several evaluated parameters were analyzed and compared by using ² statistics.

Results: Four hundred eight (50.5%) of 807 publications were from cardiologists, and 399 (49.5%) of 807 were from radiologists. Articles most commonly originated from the United States (n = 270, 53% from radiologists) and Germany (n = 178, 66% from radiologists). Developing techniques (n = 248, 64% from radiologists, P < .001) was the most frequent topic. Results of clinical trials, controlled clinical trials, and randomized controlled trials were published mainly by cardiologists (67%, P = .03; 70%, P = .2; 86%, P = .008, respectively). A majority of articles were published in cardiology journals (n = 269, 83% from cardiologists, P < .001) and radiology journals (n = 249, 82% from radiologists, P < .001).

Conclusion: The number of publications on cardiac MR imaging written by radiologists and that written by cardiologists was essentially the same.

© RSNA, 2007

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION ADVANCES IN KNOWLEDGE References

 
Cardiac magnetic resonance (MR) imaging is used in clinical practice for the evaluation of congenital heart disease, the aorta, tumors, the pericardium, cardiomyopathies, coronary artery disease, and heart transplantation and the assessment of ventricular function and mass and valvular heart disease (1).

The clinical use of this imaging technique continues to expand (2,3) because of the increasing experience and proliferation of cardiac MR imaging centers. As the worldwide prevalence of cardiovascular disease continues to rise, the use of cardiac MR imaging provides an opportunity for improved and cost-effective noninvasive assessment. Continued progress in cardiac MR imaging technology promises to further widen its clinical application in the diagnosis and management of diseases of the cardiovascular system (1,3). Cardiac MR imaging includes surgical therapies (4), heart failure (5), and other developing techniques (6).

The purpose of our study was to retrospectively evaluate the number of articles on cardiac MR imaging written by authors from radiology and cardiology departments and published in Medline-indexed journals from 1999 to 2004 and the relationship between the specialty of the author and various parameters.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION ADVANCES IN KNOWLEDGE References

 
Study Search
The Medline database (http://www.Pubmed.gov) was searched by two authors (A.M., P.S.) for articles published between 1999 and 2004. Because the Medical Subject Headings (MeSH) database (http://www.nlm.nih.gov/mesh/pubtypes2005.html) has no explicit reference to MR applications in the cardiovascular system, we used the single keyword term "cardiac MR imaging." The term was selected from the Radiology Manuscript Categorization Terms form. The search profile, performed in free language, was based on the combination of "MR-Imaging" under the Modalities/Techniques section and "Cardiac" under the Areas/Systems section of the Manuscript Categorization Terms form. We thought the use of the keyword cardiac MR imaging allowed reasonable search coverage and minimized the number of articles lost.

The search for publications was performed from November 1, 2004, to December 31, 2004, and resulted in 2761 published articles, for which the titles and abstracts were evaluated by two authors (A.M., R.A.). Articles not related to cardiac MR imaging topics (n = 745) were excluded. Moreover, articles on MR imaging studies of aortic (and thoracic) great vessels in the absence of congenital heart disease (n = 88); articles on cardiac MR imaging published by authors from other specialties, such as biomedical engineering, internal medicine, or cardiothoracic surgery (n = 654); and articles for which only the authors' names or only an institution appeared in the corresponding address field of Medline (n = 123) were excluded. There was a small (n = 10) number of articles from both radiology and cardiology departments together; these were also excluded. We restricted our analysis to original research in Medline-indexed peer-reviewed journals, thus excluding book chapters (as in the MRI Clinics series) and review articles (n = 225). There remained 916 articles for further evaluation.

Authorship Selection and Final Study Group
The nature and extent of coauthors' contributions is difficult to determine. In most circumstances, the senior author is the best representative of the department in which the research was performed and is the department's driving factor. The senior author is often the person who supervises the study or plays the most supportive role, such as a division or department director (7). On the other hand, the first author is usually the person who makes the greatest contribution to the work, research design, and performance or data analysis and who generates the first draft and makes the largest contribution to manuscript preparation (7–9). According to Slone (10), first-author papers are the most meaningful measure of research productivity. Moreover, Chew (11) has suggested that first authorship of scientific papers is the most suitable quantitative measure of research productivity. For these reasons, in our study we noted the specialty of the first author of the article.

We determined if the first author of the article was a radiologist or a cardiologist by using terms that appeared in the abstract, such as department of radiology, department of cardiology, or related terms (eg, section of radiology, cardiovascular division) and similar words in English and in different languages. Nevertheless, there were 53 institutions with a total of 179 articles on cardiac MR imaging, and the terms in the abstracts of these articles, such as cardiovascular MR unit or cardiac MR research group, gave rise to ambiguity. We developed a questionnaire that was mailed to the first author of the articles originating from these institutions to clarify the institution's biomedical specialty, as well as the specialty of the first author. Seventy articles that originated from these institutions and had a leading author who was a radiologist or a cardiologist were included in the study, but the remaining 109 articles with authors who did not respond to the questionnaire were excluded. Therefore, a total of 807 articles were finally included in our study.

Parameters Evaluated
The country of origin given in the abstract was an evaluated parameter. To investigate the scientific productivity in cardiac MR imaging of individual countries according to the publication ratio per 1 million inhabitants, the number of articles was adjusted for the number of inhabitants (adjusted publication ratio [APR]) for the most representative countries. The most representative countries were those from which 10 or more articles were published. The year 2002 was selected for this calculation because it was near the center of the period analyzed.

The sources of population statistics used to calculate APR were the Central Intelligence Agency World Factbook Web site 2002 (http://www.cia.gov/cia/publications/factbook), the United Nations World Population Division Web site (http://www.un.org/esa/population/publications/wpp2002/wpp2002wc.htm), and the Nation by Nation Web site (http://www.nationbynation.com).

The topic of the article (coronary artery disease, developing techniques, valvular disease, cardiomyopathy, congenital heart disease, cardiac tumors, pericardial disease, heart failure, transplant studies, assessment of surgical therapies, arrhythmia, and pacemakers) was considered. Studies on pathologic findings in the great vessels were not included.

The documentary type of the article according to the MeSH database in the PubMed Server (http://www.nlm.nih.gov/mesh/pubtypes2005.html) was considered. Documentary types were meta-analyses, multicenter studies, randomized controlled trials, controlled clinical trials, clinical trials, feasibility studies, validation studies, and case reports.

Corresponding publication types according to MeSH definition in the Medline database that were not explicit (eg, article topic) were assigned after detailed review of the summary of the published article. This classification was established by two authors (A.M., P.S.) in consensus. Articles on determining the effectiveness or use of cardiac MR imaging in heart disease were considered feasibility studies. Articles on the use of processes by which the reliability and relevance of cardiac MR imaging in the evaluation of diseases of the cardiovascular system were established were considered validation studies. Finally, articles on clinical presentations of diagnosis of heart disease by using cardiac MR imaging were considered case reports.

The journals in which articles were published were classified as radiology journals, cardiology journals, journals related to other medical specialties, and journals on MR topics. The latter included Journal of Magnetic Resonance Imaging; Magnetic Resonance in Medicine; Magnetic Resonance Imaging; Magnetic Resonance Materials in Physics, Biology and Medicine; NMR in Biomedicine; Journal of Magnetic Resonance; and Journal of Cardiovascular Magnetic Resonance. Radiology journals were considered to be those that were included under the subject listing "diagnostic imaging," as well as under the subject listing "radiology" in the List of Journals Indexed for Medline (12), with the exclusion of the above-mentioned seven journals on MR topics. All the journals included under the subject listing "cardiology" in the List of Journals Indexed for Medline were considered cardiology journals.

The language of the publication was considered. The study subjects and materials (classified as patients, healthy volunteers, animals, technical materials, or any combination) were considered.

Statistical Analysis
The articles were stratified and compared according to the author's specialty (radiology or cardiology), and the parameters were evaluated by using ² statistics. A parameter was considered influential on the basis of likelihood ratio test results at P .05. All statistical analyses were performed by using software (SPSS, version 11.0, 2001; SPSS, Chicago, Ill).

	RESULTS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION ADVANCES IN KNOWLEDGE References

 
Countries' Productivity
The number of articles written by radiologists (n = 399, 49.5%) was similar to that written by cardiologists (n = 408, 50.5%). The United States (n = 270, 33%) and Germany (n = 178, 22%) had the highest number of articles (Table 1). There were statistically significant differences (P < .001) among the 13 countries with 10 or more published articles; a significantly higher number of articles was published by radiologists in Germany (P < .001), Korea (P = .03), and Sweden (P = .001), whereas a significantly higher number of articles was published by cardiologists in the United Kingdom (P < .001), Spain (P = .002), and Turkey (P = .01).

Documentary Type
Documentary type (Table 3) was significantly influenced by specialty (P < .001); a significantly higher number of feasibility studies was published by radiologists, whereas cardiologists published clinical trials, controlled clinical trials, validation studies, randomized controlled trials, and case reports more frequently than radiologists. Statistically significant differences were found between cardiologists and radiologists for the following publication types: clinical trials (P = .03), randomized controlled trials (P = .008), and case reports (P .05).

Language of Publication
A statistically significant difference (P = .02) was found between the number of articles published (Table 3) in English-language journals by radiologists and that by cardiologists. Cardiologists published more English-language articles than did radiologists. There was a significantly higher number of articles published in German-language journals by radiologists (P < .001) than by cardiologists, whereas all articles in Spanish-language journals were published by cardiologists (P = .006).

Study Subjects and Materials
Significant differences were found in the distribution of articles according to study subjects and materials (Table 3); a significantly higher number of articles on studies performed with animals (P = .009) and with combinations of healthy volunteers and technical materials (P = .01) was published by radiologists, whereas a significantly higher number of articles with patients (P < .001) and with combinations of patients and healthy volunteers (P < .001) was published by cardiologists.

	DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION ADVANCES IN KNOWLEDGE References

 
The emergence of noninvasive imaging techniques for the definitive diagnosis of cardiovascular disease has greatly influenced cardiac imaging during the past 25 years. The reliance on echocardiography for the evaluation of many cardiac diseases had a profoundly negative influence on the role of the radiologist in cardiac imaging, because this modality has been nearly exclusively used by cardiologists (13). Conventional angiography also is performed mostly by cardiologists. With the increase in the importance of MR imaging, however, the role of the radiologist has been reactivated (13). In this respect, results of our analysis of the research literature for 1999–2004 showed that the number of articles by radiologists (49.5%) and that by cardiologists (50.5%) was essentially the same for cardiac MR imaging.

However, our study results show differences in publication trends between radiologists and cardiologists. The specialty of the authors who published on cardiac MR imaging varied with the country where the research was performed. For instance, the majority of articles originating from the United Kingdom were published by cardiologists. A possible explanation for this finding may relate to the existence and the staff composition of cardiovascular MR centers in the United Kingdom, such as the Cardiovascular MR Unit of the Royal Brompton Hospital, in which research is performed by cardiologists and physicists. Bunce and Pennell (14) reported on contributions from European centers to the study of MR imaging of the coronary arteries. They found that this imaging technique had developed rapidly, and there had been considerable interaction between Europe and the United States regarding technical and clinical developments during the study period of 1989–1999. Interestingly, our study results show that the country most productive in cardiac MR imaging between 1999 and 2004 was the United States, which had a balanced trend of publication by radiologists and cardiologists, although with a slightly larger number of articles published by radiologists.

We also found differences in other countries, such as Spain and Turkey, where most research is published by cardiologists. In Spain, articles on cardiac MR imaging were published in the official journal of the Spanish Society of Cardiology (Revista Española de Cardiología) in Spanish. For Turkey, all the identified articles published by cardiologists were case reports. However, we found that radiologists significantly lead publication on cardiac MR imaging research in Germany (66%) and Korea (82%) and published all identified articles originating from Sweden. In agreement with Gaylord (15), it seems that "as radiology professionals we possess equipment, knowledge and have the imaging and technical skills to perform high quality cardiac imaging."

We investigated the relative scientific productivity of individual countries by ranking countries according to the number of published articles on cardiac MR imaging per 1 million inhabitants. Thus, when the number of publications was adjusted for the number of inhabitants, we found that the United States, which had the highest overall number of published articles, then ranked seventh and had a smaller APR than the United Kingdom. The Netherlands, Switzerland, and Germany had an APR higher than two articles per 1 million inhabitants. In agreement with Coppen and Bailey (16), we believe that professional immigration could be an important factor. Some countries attract scientific immigrants of a high standard because of the opportunities available to them. Furthermore, the population-based publication rate for cardiac MR imaging also is probably influenced by other factors, like the penetrance of other imaging techniques (such as computed tomography) and socioeconomic factors (such as different reimbursements and funds provided for cardiac MR imaging) in each individual country.

With regard to the parameter of study subjects and materials, we found that articles with randomized controlled trials were published mainly by cardiologists (86%) in cardiology journals (83%) (17–26). Because of the relatively small number of clinical trial, controlled clinical trial, and randomized controlled trial articles on cardiac MR imaging published by radiologists, an opportunity exists for radiologists to become more involved.

Our study had limitations. The terms cardiovascular MR unit or cardiac MR research group may not have allowed accurate assignment of specialty because of the cooperative network of cardiologists, radiologists, physicists, and other physicians. Moreover, a potential bias in our study was to consider the specialty of the first author to be the department in which the research was performed. The Medline database includes with the abstract only the institutional affiliation of the first author of the article. Another possible limitation of our study was the exclusion of articles from other biomedical specialties. Last, because our search was restricted to Medline-indexed journals, we missed articles published in journals not indexed in this database.

In conclusion, results of our study show that the number of publications by radiologists and that by cardiologists on cardiac MR imaging is essentially the same, and the highest overall number of articles originates from the United States. We found that radiologists published more articles on developing techniques and used animals and combinations of volunteers and technical material more often in their studies than did cardiologists. The number of articles by radiologists was higher than that by cardiologists in Germany, Korea, and Sweden. We found that results of most clinical trials, controlled clinical trials, and randomized controlled trials were published by cardiologists. Articles published by cardiologists dominated mainly in the United Kingdom, Spain, and Turkey. Cardiologists used more patients and combinations of patients and volunteers in their studies and focused principally on congenital heart disease, cardiomyopathy, and heart failure.

	ADVANCES IN KNOWLEDGE

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION ADVANCES IN KNOWLEDGE References

 

• The number of publications written by radiologists on cardiac MR imaging and that by cardiologists was essentially the same.
  
• On the basis of our method of classifying journals, the radiology and cardiology journals with the highest number of published articles on cardiac MR were, respectively, Radiology and Circulation.
  
• A statistical relationship (P = .008) was found between the number of articles on randomized controlled trials and the leading author's specialty (86% from cardiologists).
  
• A statistical relationship (P < .001) was found between the number of published articles on developing techniques for cardiac MR imaging and the leading author's specialty (64% from radiologists).
  

	FOOTNOTES

 

Abbreviations: APR = adjusted publication ratio • MeSH = Medical Subject Headings

Authors stated no financial relationship to disclose.

Author contributions: Guarantor of integrity of entire study, A.M.; study concepts/study design or data acquisition or data analysis/interpretation, all authors; manuscript drafting or manuscript revision for important intellectual content, all authors; approval of final version of submitted manuscript, all authors; literature research, A.M., P.S., R.A.; statistical analysis, A.M., L.M.; and manuscript editing, all authors

	References

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION ADVANCES IN KNOWLEDGE References

 

1. Pennell DJ, Sechtem UP, Higgins CB, et al. Clinical indications for cardiovascular magnetic resonance (CMR): consensus panel report. Eur Heart J 2004;25:1940–1965.[Free Full Text]
2. Edelman RR. Contrast-enhanced MR imaging of the heart: overview of the literature. Radiology 2004;232:653–668.[Abstract/Free Full Text]
3. Constantine G, Shan K, Flamm SD, Sivananthan MU. Role of MRI in clinical cardiology. Lancet 2004;363:2162–2171.[CrossRef][Medline]
4. Kuehne T, Saeed M, Higgins CB, et al. Endovascular stents in pulmonary valve and artery in swine: feasibility study of MR imaging-guided deployment and postinterventional assessment. Radiology 2003;226:475–481.[Abstract/Free Full Text]
5. Rajappan K, Bellenger NG, Anderson L, Pennell DJ. The role of cardiovascular magnetic resonance in heart failure. Eur J Heart Fail 2000;2:241–252.[CrossRef][Medline]
6. Reeder SB, Faranesh AZ. Ultrafast pulse sequence techniques for cardiac magnetic resonance imaging. Top Magn Reson Imaging 2000;11:312–330.[CrossRef][Medline]
7. Riesenberg D, Lundberg GD. The order of authorship: who's on first? JAMA 1990;264:1857.[CrossRef][Medline]
8. Friedman PJ. Standards for authorship and publication in academic radiology. Association of University Radiologists Ad Hoc Committee on Standards for the Responsible Conduct of Research. Radiology 1993;189:33–34.
9. Hinman F Jr. Sequence of authors' names in scientific articles. JAMA 1970;212:618–619.[CrossRef][Medline]
10. Slone RM. Coauthors' contributions to major papers published in the AJR: frequency of undeserved coauthorship. AJR Am J Roentgenol 1996;167:571–579.[Abstract/Free Full Text]
11. Chew FS. The scientific literature in diagnostic radiology for American readers: a survey and analysis of journals, papers, and authors. AJR Am J Roentgenol 1986;147:1055–1061.[Abstract/Free Full Text]
12. National Library of Medicine. List of journals indexed for Medline. Bethesda, Md: National Institutes of Health, 2005; 243–313.
13. Higgins CB. Cardiac imaging. Radiology 2000;217:4–10.[Abstract/Free Full Text]
14. Bunce NH, Pennell DJ. Coronary MRA: a clinical experience in Europe. J Magn Reson Imaging 1999;10:721–727.[CrossRef][Medline]
15. Gaylord GM. Computed tomographic and magnetic resonance coronary angiography: are you ready? Radiol Manage 2002;24:16–20.[Medline]
16. Coppen A, Bailey J. 20 most-cited countries in clinical medicine ranked by population size. Lancet 2004;363:250.[Medline]
17. Schachinger V, Assmus B, Britten MB, et al. Transplantation of progenitor cells and regeneration enhancement in acute myocardial infarction: final 1-year results of the TOPCARE-AMI Trial. J Am Coll Cardiol 2004;44:1690–1699.[Abstract/Free Full Text]
18. Bellenger NG, Rajappan K, Rahman SL, et al. Effects of carvedilol on left ventricular remodelling in chronic stable heart failure: a cardiovascular magnetic resonance study. Heart 2004;90:760–764.[Abstract/Free Full Text]
19. Roest AA, Lamb HJ, van der Wall EE, et al. Cardiovascular response to physical exercise in adult patients after atrial correction for transposition of the great arteries assessed with magnetic resonance imaging. Heart 2004;90:678–684.[Abstract/Free Full Text]
20. Selvanayagam JB, Petersen SE, Francis JM, et al. Effects of off-pump versus on-pump coronary surgery on reversible and irreversible myocardial injury: a randomized trial using cardiovascular magnetic resonance imaging and biochemical markers. Circulation 2004;109:345–350.[Abstract/Free Full Text]
21. Sensky PR, Loubani M, Keal RP, Samani NJ, Sosnowski AW, Galinanes M. Does the type of prosthesis influence early left ventricular mass regression after aortic valve replacement? assessment with magnetic resonance imaging. Am Heart J 2003;146:E13.[CrossRef][Medline]
22. Nanda NC, Kitzman DW, Dittrich HC, Hall G; Imagent Clinical Investigators Group. Imagent improves endocardial border delineation, inter-reader agreement, and the accuracy of segmental wall motion assessment. Echocardiography 2003;20:151–161.[CrossRef][Medline]
23. Myers J, Wagner D, Schertler T, et al. Effects of exercise training on left ventricular volumes and function in patients with nonischemic cardiomyopathy: application of magnetic resonance myocardial tagging. Am Heart J 2002;144:719–725.[Medline]
24. Grothues F, Smith GC, Moon JC, et al. Comparison of interstudy reproducibility of cardiovascular magnetic resonance with two-dimensional echocardiography in normal subjects and in patients with heart failure or left ventricular hypertrophy. Am J Cardiol 2002;90:29–34.[CrossRef][Medline]
25. Dubach P, Myers J, Bonetti P, et al. Effects of bisoprolol fumarate on left ventricular size, function, and exercise capacity in patients with heart failure: analysis with magnetic resonance myocardial tagging. Am Heart J 2002;143:676–683.[CrossRef][Medline]
26. Aaberge L, Rootwelt K, Smith HJ, Nordstrand K, Forfang K. Effects of transmyocardial revascularization on myocardial perfusion and systolic function assessed by nuclear and magnetic resonance imaging methods. Scand Cardiovasc J 2001;35:8–13.[CrossRef][Medline]

This article has been cited by other articles:

				P. M. Colletti Cardiac Imaging: Radiologists Prepare, Participate, and Publish Am. J. Roentgenol., December 1, 2007; 189(6): 1271 - 1271. [Full Text] [PDF]

This Article Abstract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Miguel-Dasit, A. Articles by Aleixandre, R. Search for Related Content PubMed PubMed Citation Articles by Miguel-Dasit, A. Articles by Aleixandre, R.