Soo Jeong Yoon

Characteristics and Trends of Radiology Research: A Survey of Original Articles Published in AJR and Radiology between 2001 and 2010

PURPOSE To determine the characteristics and trends of the original articles published in two major American radiology journals, AJR American Journal of Roentgenology (AJR) and Radiology, between 2001 and 2010. MATERIALS AND METHODS This was a retrospective bibliometric analysis that did not involve human subjects and was exempt from institutional review board approval. All 6542 original articles published in AJR and Radiology between 2001 and 2010 were evaluated. The following information was abstracted from each article: radiologic subspecialty, radiologic technique used, type of research, sample size, study design, statistical analysis, study outcome, declared funding, number of authors, affiliation of the first author, and country of the first author. In addition, all the variables examined were presented along with the trend over time. RESULTS The most common subspecialty of study was abdominal (1219 of 6542, 18.6%), followed by vascular/interventional (804 of 6542, 12.3%). A total of 3744 (57.2%) original articles used magnetic resonance (MR) imaging or computed tomography (CT), 5495 (84.1%) were clinical research articles, 3060 (46.8%) had sample size of more than 50, 4087 (62.5%) were retrospective, 4714 (72.1%) performed statistical analysis, 6225 (95.2%) showed positive study outcome, 4784 (73.1%) were not funded, 3942 (60.3%) had four to seven authors, and 5731 (87.6%) were written by the primary author who was from a department of radiology or radiology-related specialties. The United States published 45.5% (2975 of 6542) of the articles, followed by Japan (n = 525, 8.0%), Germany (n = 485, 7.4%), and South Korea (n = 455, 7.0%). In the time trend analysis, the following variables showed a significantly positive trend: cardiac subspecialty, CT and MR imaging as the radiologic techniques, type of research as other (nonbasic, nonclinical), sample size of more than 50, four to seven as the number of authors, medicine-related department of the first author, and South Korea and Italy as countries of the first author. On the other hand, pediatric subspecialty, combined (basic and clinical) type of research, and number of authors fewer than four showed a significantly negative trend. CONCLUSION The bibliometric analysis of the AJR and Radiology journals with articles published between 2001 and 2010 revealed characteristics and trends of the current radiology research that may provide useful information to researchers and editorial staff in radiology.

Closing the Gender Gap: Increased Female Authorship in AJR and Radiology.

OBJECTIVE The purpose of this study was to evaluate gender differences in the authorship of original research articles by radiologists in two major American radiology journals, AJR and Radiology. MATERIALS AND METHODS In a retrospective bibliometric analysis, all original articles published in AJR and Radiology during three 3-year periods (1991-1993, 2001-2003, and 2011-2013) were reviewed to determine the gender of the first and corresponding radiology authors. In addition, radiologic subspecialty and country of the authors were also abstracted from each article. RESULTS The gender of the first and corresponding authors could be determined for 10,043 of 10,228 authors (98.2%) of original research in radiology. Between the periods 1991-1993 and 2011-2013, the percentage of female authors significantly increased: from 20.4% to 34.4%, respectively, among first authors (p < 0.0001); and from 18.0% to 28.7%, respectively, among corresponding authors (p < 0.0001). There was a significant correlation between the gender of the first and corresponding authors (p < 0.05). In the 2011-2013 period, the proportion of female authors was highest in breast (64.2%) and pediatric (48.2%) and lowest in vascular and interventional (18.5%) and cardiac (21.0%) subspecialties. The proportion of female authors was the highest in The Netherlands (47.3%), South Korea (37.9%), France (36.2%), and Italy (33.6%). CONCLUSION There was a significant increase in the female authorship of original research articles in two major American radiology journals between the periods 1991-1993 and 2011-2013.

Comparison of emergency cranial CT interpretation between radiology residents and neuroradiologists: transverse versus three- dimensional images

PURPOSE Three-dimensional (3D) reformatted images provide a more inclusive representation of abnormalities than transverse images in cranial computed tomography (CT). The purpose of this study was to assess the value of 3D reformations for radiology residents in the interpretation of emergency cranial CTs. MATERIALS AND METHODS In total, 218 consecutive patients who underwent emergency cranial CT scans with 3D reformation were included in this retrospective study. Four blinded readers (three radiology residents and a neuroradiologist) interpreted the transverse and 3D images in two separate sessions. Each reader assessed 1) abnormal finding(s) and the confidence score(s) (5-point scale) for transverse and 3D images, 2) added value score of 3D images (5-point scale), and 3) interpretation time for both transverse and 3D images. We analyzed discordance between each radiology resident and the neuroradiologist on a lesion-by-lesion basis. RESULTS In total, 509 lesions were detected in 218 patients. Discordance rates between the three residents and the neuroradiologist were 11.4%-20.2% (mean, 15.0%) and 8.8%-16.9% (mean, 12.1%) in the interpretation of transverse and 3D images, respectively. Confidence scores were higher for 3D images than for transverse images for all readers. The added value scores for the 3D images were relatively higher for the inexperienced residents. Interpretation times for 3D images were significantly higher than for transverse images for all readers. CONCLUSION The 3D reformations assist radiology residents in the interpretation of emergency cranial CT examinations.

Characteristics and Quality of Radiologic Randomized Controlled Trials: A Bibliometric Analysis Between 1995 and 2014

OBJECTIVE The aim of this bibliometric study was to assess the characteristics and quality of radiologic randomized controlled trials (RCTs) over the past 20 years. MATERIALS AND METHODS A PubMed search was conducted to identify radiologic RCTs (defined as RCTs in which the first author or corresponding author is affiliated with a radiology department) published between 1995 and 2014. The following information was extracted from each article: journal, radiologic subspecialty, imaging technique, number of subjects, study result, funding, number of authors, number of institutions, country of origin, and methodologic quality (assessed using the Jadad scale). RESULTS A total of 358 radiologic RCTs were published between 1995 and 2014. Dramatic increases in the numbers of radiologic RCTs were found, from 43 conducted in 1995-1999 to 172 conducted in 2010-2014. One-hundred seventeen (32.7%) RCTs were concerned with the field of vascular and interventional radiology; 78 (21.8%) evaluated more than one imaging technique; 164 (45.8%) had a sample size of 50-150 subjects; 246 (68.7%) showed positive study results; 185 (51.7%) were not funded; 179 (50.0%) had four to seven authors; 263 (73.5%) were single-center trials; 88 (24.6%) had a first author or corresponding author located in the United States; and 187 (52.2%) were of low quality. In the time trend analysis, the following variables showed a significantly positive trend: abdominal imaging subspecialty, CT as the imaging technique, more than 150 subjects, more than seven authors, and high methodologic quality. CONCLUSION The quantity and quality of radiologic RCTs have significantly increased over the past 2 decades; however, the methodologic quality remains suboptimal.

CT differentiation of abscess and non-infected fluid in the postoperative neck.

Background Differentiation of postoperative neck abscess from non-infected fluid is important because the treatment is different. Purpose To determine specific CT findings that might help to differentiate abscesses from non-infected fluid collections in the postoperative neck. Material and Methods We retrospectively reviewed CT scans of 50 patients (43 men and 7 women; mean age, 62.5±8.9 years) who had postoperative fluid collections in the neck (26 abscesses and 24 non-infected fluid collections). Diagnosis of an abscess was determined by a positive bacteria culture from the fluid collection. Diagnoses were correlated with the following CT findings: anatomic spaces involved, the maximum transverse diameter, margin, attenuation, rim enhancement, gas bubbles, and manifestations of soft tissue adjacent to a fluid collection. Results Rim enhancement pattern and soft tissue manifestations showed significant differences between abscess and non-infected fluid. The reliable CT findings for abscess were: (i) rim enhancement,> 50% of the circumference, 54% sensitive, 71% specific, and 62% accurate; and (ii) severe soft tissue manifestations, 39% sensitive, 92% specific, and 64% accurate. There were no significant differences in the anatomic spaces involved, the maximum transverse diameter, margin, attenuation, and gas bubbles between abscess and non-infected fluid. Conclusion CT findings that may help differentiate postoperative neck abscess from non-infected fluid were rim enhancement > 50% of the circumference and severe soft tissue manifestations.

The 100 top-cited articles focused on magnetic resonance: a bibliometric analysis

Background The number of citations that an article has received can be used to evaluate its impact on a particular research area. Purpose The aim of this study was to identify and characterize the 100 top-cited articles focused on magnetic resonance (MR). Material and Methods We determined the 100 top-cited articles on MR via the Scopus database, using the search term. The following information was recorded for each article: year of publication; journal title; impact factor of journal; number of citations; number of annual citations; authorship; department; institution; country; type of article; topic; MR protocol; and disease. Results The number of citations for the 100 top-cited articles was in the range of 898–5679 (median = 1342.5) and the number of annual citations was in the range of 19.7–372.4 (median = 60.9). The 100 top-cited articles were published in 46 journals, led by Magnetic Resonance in Medicine (n = 13). The majority of articles were published in 1990–1999 (n = 53), originated in the United States (n = 69), were original articles (n = 81), and dealt with the clinical application of MR (n = 57). The Department of Radiology, Massachusetts General Hospital (n = 5) was the leading institution. The majority of articles did not use any specific protocol (n = 51) and was not associated with any specific disease (n = 56). Conclusion Our study presents a detailed list and analysis of the 100 top-cited articles on MR, which provides an insight into historical development in this field.

Distribution of Citations Received by Scientific Papers Published in the Imaging Literature From 2001 to 2010: Decreasing Inequality and Polarization

OBJECTIVE The objective of this study was to assess the distribution of citations received by scientific papers published in the imaging literature between 2001 and 2010. MATERIALS AND METHODS We extracted the number of citations of all articles and reviews for 5 years after publication using the Scopus (Elsevier) citation database of imaging journals between 2001 and 2010. We quantitatively analyzed article and review citations from each journal and each year, including the number, proportion, and annual number of citations of the most- (≥ 20 citations) and least-cited (three or fewer citations) papers; ratio of most-cited to least-cited papers; 75/25 percentile citation ratio; 90/10 percentile citation ratio; Gini coefficient; and Kolkata index. RESULTS Our analysis of 124,331 articles and 13,575 reviews from 121 journals showed that the proportion of most-cited articles (from 19.6% to 27.1%) and reviews (from 19.1% to 37.2%) increased from 2001 to 2010, whereas the proportion of least-cited articles (from 32.3% to 23.0%) and reviews (from 31.9% to 15.8%) declined over the same period. The annual numbers of citations of most-cited articles and reviews both reached a peak in the fourth year after publication, whereas those of least-cited articles and reviews reached a peak in the second and fist years, respectively, after publication and thereafter decreased. The 75/25 percentile ratio for articles declined from 41.1 to 27.5 between 2001 and 2010. Over the same time, the 75/25 percentile ratio for reviews declined from 47.4 to 22.9. The 90/10 percentile ratio for articles declined from 1730.8 to 188.7; for reviews, the 90/10 percentile ratio declined from 5788.0 to 100.7. The Gini coefficient of articles and reviews also declined from 0.6116 to 0.5721 for articles and from 0.6507 to 0.5649 for reviews; the k index, from 0.7260 to 0.7088 for articles from 0.7409 to 0.7072 for reviews. CONCLUSION Inequality and polarization of citations consistently decreased in the imaging literature from 2001 to 2010.

Characteristics and quality of published animal research in the field of radiology

Background Animal research has played an important role in the field of radiology. Purpose To evaluate the characteristics and quality of published radiological animal research. Material and Methods A PubMed search was performed for radiological animal research articles (defined as studies using animal models with a radiologist as the first author) published in 1994, 2004, and 2014. The following information was extracted from each article: journal name, radiological subspecialty, imaging technique, animal species, number of animals used, number of authors, declared funding, country of origin, methodological quality, and ethical quality. Methodological and ethical quality of studies were assessed with seven-item (sample size calculation, animal age, animal sex, animal weight, inclusion and exclusion criteria, randomization, and blinded outcome assessment) and four-item (ethical review committee approval, anesthesia, pain control, and euthanasia) scales, respectively. Results The numbers of radiological animal studies markedly increased, from 91 in 1994 to 163 in 2004 and to 305 in 2014. One hundred and sixty-two (29.0%) articles focused on the neuroradiology/head and neck subspecialty, 233 (41.7%) used magnetic resonance imaging (MRI), 190 (34.0%) used mice, 254 (45.4%) used 10–30 animals, 297 (53.1%) had 4–7 authors, 392 (70.1%) were funded, and 222 (39.7%) were from the USA. Six of 7 methodological and 3/4 ethical quality items significantly improved over time. Conclusion The quantity and quality of radiological animal research has increased over the last two decades; however, methodological and ethical quality remains suboptimal.

Compressibility of Thyroid Masses: A Sonographic Sign Differentiating Benign From Malignant Lesions?

OBJECTIVE The purpose of this study was to assess the manual compressibility of thyroid masses with an ultrasound probe and to determine whether this ultrasound feature can be used to differentiate benign from malignant thyroid lesions. SUBJECTS AND METHODS We prospectively compared images obtained during compression with an ultrasound probe and noncompressed ultrasound images of 180 pathologically proven thyroid masses (51 malignant, 129 benign) smaller than 2 cm in 169 patients (127 women, 42 men; mean age, 51.2 years). The size (anteroposterior and transverse dimensions) and shape (ratio of anteroposterior to transverse dimension) of the selected lesions were measured on both noncompressed and compressed ultrasound images at a computer workstation, and the compressibility (anteroposterior-to-transverse ratio on noncompressed images minus anteroposterior-to-transverse ratio on compressed images) was calculated. Compressibility was analyzed to determine its association with histopathologic results (benign versus malignant) and the characteristics of the thyroid mass (involved lobe, location in lobe, halo, and composition). The area under the receiver operating characteristic curve was used as an indicator of performance. RESULTS The mean anteroposterior-to-transverse ratio of a thyroid mass on compressed ultrasound images was significantly lower than that on noncompressed images (0.78 ± 0.28 vs 0.92 ± 0.30; p < 0.001). The compressibility of masses was greater for benign than for malignant lesions (0.19 ± 0.16 vs 0.05 ± 0.12; p < 0.001). No statistically significant association was identified between compressibility and other characteristics of a lesion. The area under the receiver operating characteristic curve for compressibility of thyroid masses was 0.78. On the basis of a cutoff value for malignancy of compressibility less than 0.10, the sensitivity, specificity, and accuracy were 72.5%, 72.9%, and 72.8%. CONCLUSION Compressibility with an ultrasound probe is a useful criterion for differentiating benign from malignant lesions of the thyroid.