title: Cardiac CT research: exponential growth.
abstract: OBJECTIVE
  To evaluate the increase in cardiac x-ray computed tomographic (CT) research and the relative contributions of radiologists and cardiologists.
  
  
  METHODS
  This observational study of public data was exempt from institutional review board approval. The National Library of Medicine MEDLINE database was searched for articles published between 1996 and 2006 in which CT was used to acquire images of the heart. The date and journal of publication, authors' specialty and country, and article type were recorded. Trends were evaluated by using regression analysis, with P < or = .05 indicating a significant difference.
  
  
  RESULTS
  A total of 1270 articles were identified. Basic science research articles, review articles, case reports, and reports of clinical trials constituted 38%, 19%, 11%, and 7% of the total, respectively. The number of journal articles increased 15.4-fold and increased exponentially at a rate of 28% per year (P < .001). An exponential increase was seen in the number of basic science articles (P < .001), review articles (P < .001), case reports (P < .001), and reports of clinical trials (P < .001). Articles from the United States (n = 464), Germany (n = 260), Japan (n = 125), and The Netherlands (n = 76) constituted 72.8% of the world total. Radiologists published more articles (378 vs 319) and more general research articles (143 vs 100) than did cardiologists; however, cardiologists published more case reports (50 vs 29) and clinical trials (22 vs 18) than did radiologists. Cardiologists wrote more articles than did radiologists in the United States (112 vs 95) and Japan (31 vs 22), whereas radiologists wrote more articles than did cardiologists in Germany (126 vs 53) and The Netherlands (34 vs 31).
  
  
  CONCLUSIONS
  Cardiac CT research is increasing exponentially and is conducted primarily in four countries. Both radiologists and cardiologists make important contributions; however, contributions vary according to the research method used and the country in which the study was conducted. Both factors may influence future clinical adoption patterns.
authors.affiliation: Department of Radiological Sciences, David Geffen School of Medicine at UCLA, Ronald Reagan UCLA Medical Center, 757 Westwood Plaza, 1st Floor, Los Angeles, CA 90095, USA. mitagaki@mednet.ucla.edu
authors.forename: Michael W
authors.initials: MW
authors.lastname: Itagaki
authors.forename: Robert D
authors.initials: RD
authors.lastname: Suh
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Goldin
mesh_terms: D015706:Bibliometrics; D035843:Biomedical Research / Q000706:statistics & numerical data* / Q000639:trends*; D002309:Cardiology / Q000706:statistics & numerical data* / Q000639:trends*; D010506:Periodicals as Topic / Q000706:statistics & numerical data*; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data* / Q000639:trends*