Ireland's recent contribution to the radiological literature; a bibliometric analysis.

 C E. Redmond, G M. Healy, D T. Ryan, R Conway, C F. Murphy, C Ni Leidhin, J Power, D P. Brophy, E J. Heffernan.

Department of Radiology, St. Vincent's University Hospital, Dublin 4.


The aim of this study was to identify and analyse all articles published by Irish radiology departments in the medical literature since the year 2000. The PubMed database was searched to identify and review all articles published by radiologists based in the Republic of Ireland or Northern Ireland. Citation counts were then obtained and the top ten most cited articles were identified. There were 781 articles published during the study period. Of these, 558 (71%) were published in radiology journals and the remaining 223 (29%) were published in general medical journals. Abdominal radiology was the most represented sub-specialty (33% of all articles). There was a general trend of increased publications per year. Only 75 (9.6%) of articles were collaborative efforts by more than one radiology department. Irish radiology departments have a considerable research output and this has increased since the year 2000. More collaborative research between Irish radiology departments is encouraged.


The past several decades have been described as a "golden age" for Radiology due to the significant advancements experienced1. New imaging modalities introduced such as Multi-Detector Computed Tomography (MDCT), Magnetic Resonance Imaging (MRI) and Positron Emission Tomography- Computed Tomography (PET-CT) have virtually transformed the practice of modern medicine. In addition, improvements in computer processing have allowed Radiology Departments to replace hard copy images with Picture Archiving and Communication System (PACS) and manage the ever increasing workflow with Radiology Information Systems (RIS). These advancements have provided Radiologists with ample research opportunities- for example; the rate of publication of research articles on Cardiac CT increased exponentially at a rate of 28% per year between 1996-20062.

Since the establishment of the Radiological Society of Ireland in 19323, Ireland has produced many eminent Radiologists who have a high research output per capita: In a study examining the geographic origin of Radiological publications in recent years, Ireland ranked sixth in the world for total publications per million of population4.  However, information is lacking on the type and content of the research produced by Irish Radiology Departments. This study aims to identify and analyse all articles published by Irish Radiology Departments in the medical literature from the years 2000-2015.



Articles were identified by a search of the PubMed database on the 18th of March 2016. The search was limited to articles published from the 1st of January 2000 to 31st of December 2015. Articles published by Irish-based radiologists were identified by using the terms "Department of Radiology" and "Ireland" as author affiliation using the PubMed advanced search builder. Publications by radiologists based in the Republic of Ireland or Northern Ireland were included, whereas those by Irish radiologists based outside of the Republic of Ireland or Northern Ireland were excluded.  Only articles with an Irish-based radiologist as a first, second or senior author were included for analysis.  The abstract of each article was examined and information recorded. Information recorded included; article type, journal name and type, year of publication, modality, sub-specialty of radiology and number of institutions involved in the production of each article. The citation count of each article was obtained from Thomson Reuters’ Web of Science (case reports and letters to the Editor were excluded from the citation analysis) and the top ten most cited articles were identified. The impact factor for the ten journals with the most published articles was recorded using the "IncitesTM Journal Citation Reports".



There were 781 articles published by Irish-based radiologists for the study period available on PubMed. Of these, 558 (71%) were published in radiology journals and the remaining 223 (29%) were published in general medical journals.

The imaging modalities researched were computed tomography (148 articles, 19%), magnetic resonance imaging (121 articles, 15%), fluoroscopy (49 articles, 6%), ultrasonography (41 articles, 5%), nuclear medicine (26 articles 3%), and radiography/mammography (23 articles, 3%).  There were 314 articles (40%) that pertained to multiple imaging modalities and 59 articles (8%) that were non-imaging modality related research. Regarding the various representation of each sub-specialty; there were 257 articles pertaining to abdominal radiology (33% of all articles), 137 articles (18%) on interventional radiology, 136 articles (17%) on musculoskeletal radiology, 108 articles (14%) on cardiothoracic radiology, 56 articles (7%) on neuroradiology and 15 articles (2%) on breast radiology. There were 72 articles (9%) that covered multiple sub-specialties. Original research articles constituted the largest article category (323, 41%), while 257 (33%) were case reports/letters to the editor and 201 (26%) were review articles/pictorial essays. The journal with the most publications was the American Journal of Roentgenology with 66 articles over the study period. The ten journals with the most published articles are listed in table 1. 

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The number of article citations ranged from 1 to 175 citations (mean: 14). The top ten most influential articles, as defined by total number of citations, in the study time period are listed in table 2. The number of publications per year over the study period is demonstrated in figure 1. There was a general trend of increased publications per year over the study period, the most productive year was 2015 with 81 publications. Only 75 (9.6%) of articles were collaborative efforts by more than one Radiology Department. Of these, 25 (33%) articles involved collaborations between one or more Irish radiology department, while 50 (66%) articles involved collaborations between an Irish Radiology Department and one or more international Radiology Departments.

S-6296 pic 2


Bibliometry is a quantitative technique of evaluation of scientific articles published in a defined cohort of journals over a given period of time5,6 . In recent years, the Irish contribution to the literature of other medical specialties such as Orthopaedics7 and Plastic Surgery8 has been bibliometrically analysed. These studies have identified interesting trends and characteristics of Irish research in these specialties, and are of benefit for future research planning and funding. In our study, it is positive to observe that the research output of Irish Radiology Departments increased over the examined time period. Abdominal Radiology has been the most researched of the sub-specialties, constituting one third of all published articles. Interventional Radiology, a subspecialty which has experienced a rapidly evolving role in healthcare during the study time period, also featured strongly. It was the second most researched of the sub-specialties and it accounted for four of the top ten most cited articles over the time period.  There was a paucity of articles published on Breast Radiology and Nuclear Medicine and the more limited exposure Radiology Trainees have to these sub-specialties is likely a contributory factor to this.  Perhaps unsurprisingly, articles focusing on the more complex and contemporary imaging modalities such as CT and MRI greatly outnumbered those focusing on more conventional modalities such as Radiography and Ultrasonography.  It is interesting to note the geographically varied target audience for Irish research over the study period; the journals with the most published articles were a mix of North American, continental European, British and Irish Journals.

 A finding of concern is the low rate of inter-departmental research collaboration.  Remarkably only 25 of all articles (3%) were published by two or more Irish Departments working together. Irish Radiology Departments collaborated with international Radiology Departments more frequently than other Irish Radiology Departments. The benefits of a collaborative approach to research are numerous9 and it is of particular importance in a country of small population such as Ireland. We believe that for Ireland to realize its full potential in academic radiology, a formal collaborative research program should be established. This would be particularly timely given the recent establishment of the National Integrated Medical Imaging System (NIMIS).

 There are current challenges for Irish Radiologists and Radiology Trainees to complete research. The demand for imaging studies is ever increasing and this has been observed both internationally10 and in Ireland- for instance Culleton et al11 observed an increase of 210% in CT imaging performed during weekends in an Irish Hospital from 2001-2010. In addition, the ongoing pressure to comply with the European Working Time Directive may result in a change to a "night shift" working system for Trainees, thereby reducing precious contact time with research supervisors.  Furthermore, very few Irish Radiologists are working full time in Academic Radiology and this looks set to continue- in a recent survey of British and Irish Radiology Trainees only 5% of respondents aspired to work in the field of Academic Radiology12. Despite these challenges, Irish Radiologists have a considerable research output, which compares favourably with that of other Irish medical specialties7,8.

This study has several limitations. Many Irish Radiologists are practicing abroad and actively involved in research, however this has not been analysed as our focus was the research output of Irish Radiology Departments. Indeed we believe an analysis of the research output of Irish Radiologists abroad would be a worthwhile separate study. Furthermore, defining the most "influential" articles based solely on total number of citations will inherently favour older articles which have had a longer lead time to accrue citations.

 In conclusion, this study depicts a comprehensive overview of the recent research output of Irish Radiology Departments. Despite ongoing challenges discussed herein, Irish Radiology Departments have a considerable research output, which has increased since the year 2000. Irish research is particularly strong in the areas of Abdominal Radiology and Interventional Radiology, which constituted the focus of more than half of all of the articles. More collaborative research studies between Irish Radiology Departments are encouraged and a formal collaborative research program may be beneficial.



Dr. Ciaran Redmond, Department of Radiology, St. Vincent’s University Hospital, Dublin 4, Ireland.

Email: [email protected]

Tel: +353 1 2213704


Conflict of Interest

The authors have no conflict of interest to declare- financial or otherwise



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