Impact of the National Institutes of Health on radiology research.

Purpose: To retrospectively quantify the characteristics of published radiology research sponsored by the National Institutes of Health (NIH) and to retrospectively characterize the contribution of the individual NIH institutes.

Materials And Methods: The National Library of Medicine's PubMed database was searched for all articles published by U.S. radiology departments from 1996 to 2005. Methodology and NIH grant support were recorded for each article. Data were analyzed with linear regression curve estimation, with P < or = .05 indicating a significant difference.

Results: Worldwide, 76 838 articles were identified, with 30 156 (39.25%) originating from the United States. The NIH funded 28.36% of clinical trials and 18.58% of U.S. articles overall. The proportion of funded articles increased annually by 1.1% (P < .001) overall, by 3.5% for clinical trials (P < .001), and by 5.2% for multicenter trials (P < .001). By 2005, 54.9% of all clinical trials and 55.6% of multicenter trials were NIH funded. The National Cancer Institute sponsored the most articles (2505 articles; growth, 13.5 articles per year; P = .003), followed by the National Institute of Neurological Disorders and Stroke (1030 articles; growth, 4.7 articles per year; P = .012). The newest NIH institute, the National Institute of Biomedical Imaging and Bioengineering, had the most rapid growth (320 articles; growth, 43.7 articles per year; P = .01).

Conclusion: The NIH funded less than one-fifth of all U.S. radiology articles, but the proportion of funded articles is increasing, especially for clinical trials, where in 2005 more than half received funding; cancer and neurologic disease research is relatively well funded.