Objectives: To compare the abstract structure in the 70 highest-rank imaging journals with that of the two highest-rank journals in each of 35 non-imaging biomedical categories, according to 2008 impact factors.
Methods: We searched on MEDLINE for articles published in high-ranking imaging and non-imaging journals. Abstract format was considered as: IMRaD (Introduction, Methods, Results, and Discussion/conclusion); extended structured (ES), when including headings other than IMRaD; or narrative (without headings).
Results: Abstracts of the 70 highest-rank imaging journals were: IMRaD, n = 43 (61%); narrative, n = 27 (39%); ES, n = 0. Abstracts of the 70 highest-rank non-imaging journals were: IMRaD, n = 26 (37%); narrative, n = 35 (50%); ES, n = 9 (13%) (p = 0.001). Additional headings were: study design, n = 7; measurements, n = 7; context/setting, n = 4; interventions, n = 2; rationale, n = 1; level of evidence, n = 1; clinical relevance, n = 1. Study design was declared in 12/23 abstracts (57%) and 21/23 (91%) article bodies in Radiology, 6/21 (29%) and 10/21 (48%) in Investigative Radiology, 11/24 (46%) and 18/24 (75%) in European Radiology, and 12/30 (40%) and 23/30 (77%) in American Journal of Roentgenology, respectively.
Conclusions: Although about 60% of imaging journals adhere to IMRaD format, 13% of non-imaging journals requires additional headings; ES abstracts may assist readers in selecting full articles to be read.