The 100 most-cited and 100 most-mentioned COVID-19-related radiological articles: a comparative bibliometric analysis.

OBJECTIVES: This study aimed to identify the 100 most-cited and 100 most-mentioned coronavirus disease-2019 (COVID-19)-related radiological articles and compare their characteristics. MATERIALS AND METHODS: We searched the Web of Science and Altmetric.com using the search terms "COVID," "COVID-19," "Coronavirus," "SARS-CoV-2," "nCoV," and "pandemic" to identify the most-cited and most-mentioned COVID-19-related articles. We identified the top 100 most-cited and 100 most-mentioned articles in the field of radiology, regardless of their publication journal. We extracted the information from the listed articles and compared the characteristics between the most-cited and most-mentioned. RESULTS: Thirty (30%) articles were featured in the lists of the most-cited and most-mentioned articles. The comparison of the 100 most-cited and most-mentioned articles on each list showed that the most frequently cited articles were published in November 2020 and before (p < .001), originated from China (p < .001), covered the topic of diagnosis of COVID-19 (p < .001), and were related to the subspecialty of pulmonary imaging (p < .001); the most frequently mentioned articles were published in December 2020 and after (p < .001), originated from the USA (p < .001), covered the topic of diagnosis of sequelae of COVID-19 (p = .013) and post-vaccination complications (p < .001), and were related to the subspecialties of cardiac imaging (p < .001) and neuroradiology (p < .013). CONCLUSION: Significant differences were observed in publication date, country of origin, topic, and subspecialty of scientific knowledge related to COVID-19 in the field of radiology, between citation and public dissemination. CLINICAL RELEVANCE STATEMENT: This bibliometric analysis compares the 100 most-cited and 100 most-mentioned COVID-19-related radiologic articles, aiming to provide valuable insights into the patterns of knowledge dissemination during the pandemic era. KEY POINTS: • Thirty articles were featured on the lists of the 100 most-cited and 100 most-mentioned COVID-19-related articles. • The 70 unique most-cited articles more frequently originated from China (48.6%), while the unique most-mentioned articles more frequently originated from the USA (51.4%) (p < 0.001). • The 70 unique most-mentioned articles were more frequently related to cardiac imaging (25.7% vs.0%, p < 0.001) and neuroradiology (15.7% vs. 1.4%, p < 0.005) compared to the unique most-mentioned articles.

Usefulness of two-dimensional shear wave elastography in the assessment of non-alcoholic fatty liver disease in children and adolescents.

Two-dimensional shear wave elastography (2D-SWE) evaluates liver stiffness using a non-invasive method, but studies in the paediatric population are rare. This study evaluated the role of 2D-SWE in the diagnosis and severity of paediatric non-alcoholic fatty liver disease (NAFLD). In total, 131 patients with NAFLD and 25 healthy controls were enrolled in this study. The diagnosis and severity of NAFLD were initially assessed using the ultrasound fatty liver index (US-FLI), and all participants underwent 2D-SWE. US-FLI semi-quantitatively measures the severity of NAFLD on a scale of 2-8. The assessment of liver stiffness measurement (LSM) by 2D-SWE is presented in kilopascals (kPa). The NAFLD group was characterised by significantly higher LSM (4.40 ± 0.90 kPa) than the control group (3.76 ± 0.28 kPa) (P < 0.001). 2D-SWE significantly correlated with age, height, weight, body mass index, glucose, aspartate aminotransferase, alanine aminotransferase, high-density lipoprotein cholesterol, US-FLI, and triglyceride-glucose index (P < 0.001). In the receiver operating characteristic curve analysis, the area under the curve of LSM for predicting US-FLI ≥ 2 and ≥ 6 was 0.784 (P < 0.001) and 0.819 (P < 0.001), respectively. In conclusion, we suggest that 2D-SWE can be used as a non-invasive diagnostic tool for diagnosing and assessing the severity of paediatric NAFLD.

Scientific Publications on Thyroid Ultrasound between 2001 and 2020: Differences in Research Characteristics by Disciplines.

OBJECTIVE: To analyze the characteristics and trends of scientific publications on thyroid ultrasound (US) from 2001 to 2020, specifically examining the differences among disciplines. MATERIALS AND METHODS: The MEDLINE database was searched for scientific articles on thyroid US published between 2001 and 2020 using the PubMed online service. The evaluated parameters included year of publication, type of document, topic, funding, first author's specialty, journal name, subject category, impact factor, and quartile ranking of the publishing journal, country, and language. Relationships between the first author's specialty (radiology, internal medicine, surgery, otorhinolaryngology, and miscellaneous) and other parameters were analyzed. RESULTS: A total of 2917 thyroid US publications were published between 2001 and 2020, which followed an exponential growth pattern, with an annual growth rate of 11.6%. Radiology produced the most publications (n = 1290, 44.2%), followed by internal medicine (n = 716, 24.5%), surgery (n = 409, 14.0%), and otorhinolaryngology (n = 171, 5.9%). Otorhinolaryngology and internal medicine published significantly more case reports than radiology (p < 0.001, each). Radiology published a significantly higher proportion of publications on imaging diagnosis (p < 0.001 for all) and a significantly lower proportion of publications on biopsy (p < 0.001 for all) than the other disciplines. Publications produced by radiology authors were less frequently published in Q1 journals than those from other disciplines (p < 0.005 for internal medicine and miscellaneous disciplines and < 0.01 for surgery and otorhinolaryngology). China contributed the greatest number of publications (n = 622, 21.3%), followed by South Korea (n = 478, 16.4%) and the United States (n = 468, 16.0%). CONCLUSION: Radiology produced the most publications for thyroid US than any other discipline. Radiology authors published more notably on imaging diagnosis compared to other topics and in journals with lower impact factors compared to authors in other disciplines.

A comprehensive analysis of self-corrected publications in the imaging literature.

BACKGROUND: The characteristics of self-corrected publications have not been fully evaluated. PURPOSE: To evaluate the annual number and characteristics of self-corrected publications in the imaging literature within the last 20 years. MATERIAL AND METHODS: We searched MEDLINE (via PubMed) using the following keyword: ("Published Erratum" [Publication Type] OR "Corrected and Republished Article" [Publication Type]) in the imaging literature to identify all self-corrected publications in which initial versions of articles were published during 1999-2018. Extracted data included: date of publication of the original version; date of correction notification; the time interval between initial publication and correction; journal name; journal impact factor (IF); type of articles; number of authors; country of origin; and location of errors. Journals were divided into four quartiles (Q1-Q4) based on their IF. RESULTS: A total of 1071 self-corrected publications were identified, representing 0.30% of all papers published in the imaging literature. Trend analysis showed exponential growth of the number and rate of self-corrected publications during 1999-2018. The median (range) time interval from initial publication to correction was 120 days (0-7755 days). The rate of self-corrected publications in Q4 journals (0.17%) was significantly lower than those in Q1 (0.35%, P<0.0001), Q2 (0.26%, P=0.0007), and Q3 (0.30%, P<0.0001) journals. Additionally, 80.8% of self-corrected publications were original articles, 29.2% were from the USA, and 30.7% were corrected for author information (name, affiliation, and email address). CONCLUSION: Self-corrected publications in the imaging literature have increased exponentially during 1999-2018 and author information was the most common location of error correction.

The Most Widely Disseminated COVID-19-Related Scientific Publications in Online Media: A Bibliometric Analysis of the Top 100 Articles with the Highest Altmetric Attention Scores.

The novel coronavirus disease 2019 (COVID-19) is a global pandemic. This study's aim was to identify and characterize the top 100 COVID-19-related scientific publications, which had received the highest Altmetric Attention Scores (AASs). Hence, we searched Altmetric Explorer using search terms such as "COVID" or "COVID-19" or "Coronavirus" or "SARS-CoV-2" or "nCoV" and then selected the top 100 articles with the highest AASs. For each article identified, we extracted the following information: the overall AAS, publishing journal, journal impact factor (IF), date of publication, language, country of origin, document type, main topic, and accessibility. The top 100 articles most frequently were published in journals with high (>10.0) IF (n = 67), were published between March and July 2020 (n = 67), were written in English (n = 100), originated in the United States (n = 45), were original articles (n = 59), dealt with treatment and clinical manifestations (n = 33), and had open access (n = 98). Our study provides important information pertaining to the dissemination of scientific knowledge about COVID-19 in online media.

Characteristics of the Most Cited, Most Downloaded, and Most Mentioned Articles in General Medical Journals: A Comparative Bibliometric Analysis.

We compared the characteristics of the most cited, most downloaded, and most mentioned (the highest Altmetric Attention Score) articles published in general medical journals. We identified the 640 most frequently cited, 662 most frequently downloaded, and 652 most mentioned articles from 48 general medical journals. A comparison was made of the following characteristics of articles in the most cited, most downloaded, and most mentioned articles: medical specialty, publication type, country of origin, year of publication, and accessibility. There was only a 2.5% overlap in these three groups. Original articles were the more frequent among the most mentioned articles, whereas reviews, case reports, and guidelines/consensus statements were more frequent among the most downloaded articles. The most cited articles were more frequently published in 2010 and before, whereas the most downloaded articles were published in 2017-2018. The most mentioned articles were more frequently open-access articles, compared to the most downloaded articles. The most cited were more frequently older, the most downloaded were more frequently recent and educational, and the most mentioned were more frequently original and open-access articles. The results of our study may provide insights into various measures of article impact.

Analysis of the altmetric top 100 articles with the highest altmetric attention scores in medical imaging journals.

PURPOSE: Alternative metrics (altmetrics) provides a complementary measure of the impact of scientific articles. The aim of this study was to identify and characterize the top 100 articles with the highest Altmetric attention score (AAS) in medical imaging journals. MATERIALS AND METHODS: We searched for AASs articles published in 116 journals in the subject category "Radiology, Nuclear Medicine and Medical Imaging" using the Web of Science. We determined the top 100 articles with the highest AAS using the Altmetric.com database, and then analyzed them with regard to the publishing journal, year, country of origin, type of article, subspecialty, main topic, and imaging technique. RESULTS: The top 100 articles were published in 18 imaging journals, led by Radiology (47%). These articles were published from 2016 to 2018 (94%). Most of the articles were from the United States (62%) and were original clinical studies (59%). The most common subspecialties and imaging technique of study were neuroimaging (30%) and MRI (35%). The main topics of articles were brain disease and function (30%). CONCLUSION: Our study presents a detailed list and analysis of the top 100 articles with the highest AAS in imaging literature, which provides unique characteristics representing the public's attention in this field.

Top-cited articles versus top Altmetric articles in nuclear medicine: a comparative bibliometric analysis.

BACKGROUND: The impact of any scientific article has traditionally been measured by the number of citations received. More recently, alternative metrics (altmetrics) reflect the digital dissemination of knowledge across the online mediasphere. PURPOSE: To evaluate and compare the characteristics of top-cited articles with those of top Altmetric articles related to nuclear medicine (NM). MATERIAL AND METHODS: We performed a search of the Web of Science and Altmetric databases using 114 search terms to identify the 50 top-cited and 50 top Altmetric articles, respectively, in the field of NM. We then compared the following characteristics of the selected articles: publication type; journal category; country of origin; year of publication; topic; imaging modality; and accessibility. Chi-square tests were performed for statistical analysis. RESULTS: There were no overlaps between the 50 top-cited and 50 top Altmetric articles. In general, compared to the leading Altmetric articles in this field, the cited articles were: more frequently review works published in NM and radiology journals (76% vs. 13%, P = 0.000); published in or before 2005 (84% vs. 0%, P = 0.000); the majority were related to oncology (56% vs. 44%, P = 0.000); and originated from the Netherlands (12% vs. 0%, P = 0.000). Compared to the top-cited articles, the leading Altmetric articles were: more frequently original articles published in other clinical field journals (54% vs. 0%, P = 0.000); primarily published between 2016 and 2018 (70% vs. 0%, P = 0.000); focused on neurology (50% vs. 22%, P = 0.000); and originated from the UK (18% vs. 2%, P = 0.000). CONCLUSION: Citation counts and Altmetric scores represent unique perspectives for evaluating the impact of NM research.

Radiological Clinical Practice Guidelines Published in the Last Decade: A Bibliometric Analysis.

OBJECTIVES: To provide a comprehensive review of radiological clinical practice guidelines (CPGs) and to establish their characteristics and impact in the field of radiology. MATERIAL AND METHODS: A MEDLINE search was performed for CPGs in which at least half of the authors were from the radiology or imaging department. The following information was extracted from each CPG: year of publication, journal, provider, number of authors, number of pages, number of references, collaboration, country of origin, radiological subspecialty, imaging modality used, topic, source of funding, and number and pattern of citations. RESULTS: In total, 120 radiological CPGs published between July 2006 and June 2016 were identified. One hundred nine (90.8%) radiological CPGs were published in radiology journals, 96 (80.0%) were provided by the scientific community, 108 (90.0%) were collaborative studies, 64 (53.3%) originated from the United States, 36 (30.0%) were concerned with the field of vascular/interventional radiology, 38 (31.7%) used combined imaging techniques, 52 (43.3%) were focused on interpretation and management, and 118 (98.4%) were not funded. Radiological CPGs included a median of 8 authors, 9 pages, and 49 references. The median number of citations and annual citations were 18 (range, 0-540) and 3.5 (range, 0-75.6), respectively. CONCLUSION: Our study presents several interesting insights into the characteristics and impact of radiological CPGs.

Diagnostic performance of CT, MRI, and their combined use for the assessment of the direct cranial or intracranial extension of malignant head and neck tumors.

BACKGROUND: Preoperative radiological evaluation of the cranial or intracranial extension of malignant head and neck tumors is critical in the planning of curative surgery. PURPOSE: To assess the diagnostic accuracy of computed tomography (CT) combined with magnetic resonance imaging (MRI), compared to CT or MRI alone in diagnosing the direct cranial or intracranial extension of malignant head and neck tumors, using histopathologic results as the reference standard. MATERIAL AND METHODS: CT and MRI images in 41 patients with malignant head and neck tumors abutting the skull were retrospectively reviewed. The images were evaluated for the presence or absence of skull invasion (erosion/destruction of the skull), dural invasion (nodular dural enhancement), and brain invasion (enhancing brain lesion with or without brain swelling/edema). The results of the CT alone, MRI alone, and CT combined with MRI were compared with the histopathologic findings. RESULTS: Of the 41 patients studied, ten had no invasion, eight had skull invasion, 17 had dural invasion, and six had brain invasion by tumor. The sensitivity/specificity/accuracy of CT alone, MRI alone, and CT combined with MRI for diagnosing intracranial extension were 78.0%/100%/94.5%, 85.4%/80.5%/93.9%, and 95.1%/100%/98.8%, respectively. The sensitivity of CT combined with MRI was significantly higher than those of CT alone ( P = 0.0156) and MRI alone ( P = 0.0313). CONCLUSION: CT combined with MRI is a more sensitive tool for the diagnosis of the direct cranial or intracranial extension of malignant head and neck tumors than CT alone and MRI alone.

The most downloaded and most cited articles in radiology journals: a comparative bibliometric analysis.

OBJECTIVES: To evaluate and compare the characteristics of the most downloaded and most cited articles in radiology journals. METHODS: We selected 41 radiology journals that provided lists of both the most downloaded and most cited articles on their websites, and identified the 596 most downloaded articles and 596 most cited articles. We compared the following characteristics of the most downloaded and most cited articles: year of publication, journal title, department of the first author, country of origin, publication type, radiologic subspecialty, radiologic technique and accessibility. RESULTS: Compared to the most cited articles, the most downloaded articles were more frequently review articles (36.1% vs 17.1%, p < 0.05), case reports (5.9% vs 3.2%, p < 0.05), guidelines/consensus statements (5.4% vs 2.7%, p < 0.05), editorials/commentaries (3.7% vs 0.7%, p < 0.05) and pictorial essays (2.0% vs 0.2%, p < 0.05). Compared to the most cited articles, the most downloaded articles more frequently originated from the UK (8.7% vs 5.0%, p < 0.05) and were more frequently free-access articles (46.0% vs 39.4%, p < 0.05). CONCLUSION: Educational and free-access articles are more frequent among the most downloaded articles. KEY POINTS: • There was only small overlap between the most downloaded and most cited articles. • Educational articles were more frequent among the most downloaded articles. • Free-access articles are more frequent among the most downloaded articles.

Intraobserver and Interobserver Variability in Ultrasound Measurements of Thyroid Nodules.

OBJECTIVES: The purpose of this study was to assess the intraobserver and interobserver variability in ultrasound (US) measurements of thyroid nodules. METHODS: We performed a prospective study of the US examinations of 73 patients with 122 thyroid nodules greater than 5 mm in size. Ultrasound measurements in 4 dimensions (anteroposterior, transverse, longitudinal, and maximum diameters) and measurement of the estimated volume (using the ellipsoid formula) of each thyroid nodule were performed twice by 2 independent radiologists (A and B, with 10 years and 6 months of experience, respectively). The intraobserver and interobserver variability in measurements of thyroid nodules was assessed by a Bland-Altman analysis of agreement. The absolute values for intraobserver and interobserver variability were compared by a paired t test. RESULTS: The 95% intraobserver and interobserver limits of agreement for the anteroposterior, transverse, longitudinal, and maximum diameters and estimated volume of thyroid nodules were ±18.2%, ± 14.3%, and ±21.0%; ± 17.2%%, ± 17.3%, and 18.2%; ± 14.6%, ± 15.5%, and ±22.3%; ± 13.8%, ± 15.5%, and ±19.6%; and ±30.2%, ± 27.7%, and ±44.1%, respectively. The absolute values for intraobserver variability were lower than those for interobserver variability for all measurements. CONCLUSIONS: There was considerable intraobserver and interobserver variability in US measurement of thyroid nodules, which must be taken into account during follow-up US examinations of patients with thyroid nodules.

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.

The 100 Top-Cited Articles in Pulmonary Imaging: A Bibliometric Analysis.

PURPOSE: The purpose of this study was to identify and characterize the 100 top-cited articles in pulmonary imaging. MATERIALS AND METHODS: From the database of Journal Citation Reports, 274 journals whose scope included pulmonary imaging were selected. The Web of Science search tools were then used to identify the 100 top-cited articles in the subject of pulmonary imaging published in these journals. The parameters used to analyze the characteristics of the 100 top-cited articles were journal (including subject category and impact factor), publication year, number of citations and annual citations, department and institution of authors, country of origin, article type, imaging technique, and topic. RESULTS: The 100 top-cited articles in pulmonary imaging were published between 1953 and 2012, with 43 published between 2000 and 2009. Citations ranged from 199 to 1447, and annual citations ranged from 5.1 to 314. The majority of articles were published in radiology or imaging journals (n=64), originated in the United States (n=49), were original articles (n=87), used computed tomography (n=66), and were based on the topic of pulmonary thromboembolism (n=18). Department of Radiology, Mayo Clinic (n=7), and Department of Radiology, University of British Columbia and Vancouver General Hospital (n=7), were the leading institutions, and Müller NL (n=11) was the most prolific author. CONCLUSIONS: Our study lists the 100 top-cited articles in pulmonary imaging, provides an insight into historical developments, and allows for recognition of advances in this field.

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.

Trend Toward an Increase in Authorship for Leading Radiology Journals.

OBJECTIVE: The purpose of this study was to determine authorship trends in two leading radiology journals over the past 2 decades. MATERIALS AND METHODS: All original articles (n = 5195) published in AJR and Radiology for the periods 1991-1993, 2001-2003, and 2011-2013 were reviewed. The following variables were extrapolated from each article: number of authors, radiologic subspecialty, and country of origin. The number of authors listed per article was correlated with the publication period, journal, radiologic subspecialty, and country of origin. RESULTS: The mean number of authors per article increased from 5.1 in 1991-1993 to 6.2 in 2001-2003 and to 7.1 in 2011-2013 across both journals (p < 0.0001). Both AJR and Radiology had statistically significant increases in the number of authors per article over time, but the number of authors per article in Radiology was significantly higher than that in AJR (p < 0.0001 for all study periods). The number of authors per article significantly increased for all radiologic subspecialties. The mean numbers of authors per article by country of origin are as follows: Italy, 8.3; Japan, 7.6; France, 7.5; Germany, 7.4; China, 7.3; Austria, 7.2; and South Korea, 6.8. These were significantly higher than the mean number of authors from Switzerland, which was 6.3. CONCLUSION: The number of authors significantly and consistently increased in two leading radiology journals over the past 2 decades.

Angiographic analysis of the lateral intercostal artery perforator of the posterior intercostal artery: anatomic variation and clinical significance.

PURPOSE: Knowledge of the anatomic variations of the posterior intercostal artery (PICA) and its major branches is important during transthoracic procedures and surgery. We aimed to identify the anatomic features and variations of the lateral intercostal artery perforator (LICAP) of the PICA with selective PICA arteriography. METHODS: We retrospectively evaluated 353 PICAs in 75 patients with selective PICA arteriography for the following characteristics: incidence, length (as number of traversed intercostal spaces), distribution at the hemithorax (medial half vs. lateral half), and size as compared to the collateral intercostal artery of the PICA. RESULTS: The incidence of LICAPs was 35.9% (127/353). LICAPs were most commonly observed in the right 8th-11th intercostal spaces (33%, 42/127) and in the medial half of the hemithorax (85%, 108/127). Most LICAPs were as long as two (35.4%, 45/127) or three intercostal spaces (60.6%, 77/127). Compared to the collateral intercostal artery, 42.5% of LICAPs were larger (54/127), with most of these observed in the right 4th-7th intercostal spaces (48.8%, 22/54). CONCLUSION: We propose the clinical significance of the LICAP as a potential risk factor for iatrogenic injury during posterior transthoracic intervention and thoracic surgery. For example, skin incisions must be as superficial as possible and directed vertically at the right 4th-7th intercostal spaces and the medial half of the thorax. Awareness of the anatomical variations of the LICAPs of the PICA will allow surgeons and interventional radiologists to avoid iatrogenic arterial injuries during posterior transthoracic procedures and surgery.

Incidental focal FDG uptake in the parotid glands on PET/CT in patients with head and neck malignancy.

OBJECTIVES: To evaluate the prevalence and clinical significance of focal parotid lesions identified by (18)F- FDG PET/CT in patients with nonparotid head and neck malignancies. METHODS: From 3,638 PET/CT examinations using (18)F-FDG conducted on 1,342 patients with nonparotid head and neck malignancies, we retrospectively identified patients showing incidental focal FDG uptake in the parotid glands. The diagnosis of parotid lesions was confirmed histopathologically or on imaging follow-up. Patient demographics, clinical features, maximum standardized uptake value (SUV(max)) on PET images, size and attenuation on corresponding contrast-enhanced CT images were assessed and correlated with the final diagnosis. RESULTS: The prevalence of incidental focal parotid FDG uptake on PET/CT was 2.1% (95% CI 1.4 - 3.0%). Among 21 patients with focal parotid lesions confirmed histologically or on imaging follow-up, 7 (33.3%) had malignant lesions (all metastases) and 14 (66.7%) had benign lesions (four pleomorphic adenomas, two Warthin's tumours, one benign lymph node, one granulomatous lesion, six lesions without histopathological confirmation). There were no significant differences in age, sex, SUV(max) or CT findings between patients with benign and those with malignant lesions. CONCLUSION: Focal parotid FDG uptake on PET/CT in patients with head and neck malignancy warrants further investigations to ensure adequate therapy for incidental parotid lesions. KEY POINTS: • The prevalence of parotid incidentaloma on PET in head and neck malignancy was 2.1% • The malignancy rate of incidental focal parotid FDG uptake was 33.3% • SUV max could not reliably differentiate malignant from benign incidental parotid lesions.

Harmonic ultrasonography for the detection of microlithiasis in the gallbladder.

PURPOSE: To validate the use of harmonic ultrasonography (US) in the detection of gallbladder microlithiasis. METHODS: From November 30, 2012, to January 18, 2014, fundamental US (FUS) and harmonic US with a high background noise (HUS-N) were performed for evaluation of gallbladder during the routine abdomen US. During the US, a dot-like stone (or stones) with Brownian motion was regarded as a positive finding of microlithiasis. Fifty-five patients with microlithiasis in the gallbladder detected on US were enrolled as the subjects of a retrospective review. With respect to the obtained images, two abdominal radiologists independently scored the conspicuity of gallbladder microlithiasis on FUS and HUS-N by using a 4-grade scale. The statistical analysis employed a kappa test and a Wilcoxon rank-sum test. RESULTS: For FUS, the conspicuity grades of gallbladder microlithiasis were G1 in 25 and 37, G2 in 21 and 9, G3 in 6 and 6, G4 in 3 and 3 patients, while HUS-N showed G1 in 0 and 0, G2 in 3 and 2, G3 in 12 and 15, and G4 in 40 and 38 patients, respectively, by each of the two radiologists. The kappa value was 0.633 for FUS between the two radiologists and 0.708 for HUS-N. HUS-N showed better conspicuity of gallbladder microlithiasis than FUS with significant P-values of less than 0.001 and 0.001 for the two radiologists, respectively. CONCLUSION: Compared with FUS, HUS-N enables better detection of microlithiasis in the gallbladder.