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.

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.

Mediastinal Lymph Node Metastasis from Head and Neck Cancer: Predictive Factors and Imaging Features

Purpose

To assess the predictive factors and describe the imaging features of mediastinal lymph node (MLN) metastases in patients with head and neck cancer.

Materials and Methods

We compared the clinical features and disease characteristics (sex, age, site of primary tumor, histologic type, history of prior treatments, TNM stages, and metastasis in cervical LNs) of patients with head and neck cancers between the MLN metastasis and no MLN metastasis groups. We also evaluated the chest CT (distribution and maximum dimension of the largest LN) and PET/CT (maximum standardized uptake value) features of MLN metastases based on the MLN classification.

Results

Of the 470 patients with head and neck cancer, 55 (11.7%) had MLN metastasis, involving 150 mediastinal stations. Hypopharynx cancer, recurrent tumor, T4 stage, N2/N3 stages, and M1 stage were found to be significant predicting factors for MLN metastasis. The most common location of MLN metastasis was ipsilateral station 2 (upper paratracheal LNs, 36.4%), followed by ipsilateral station 11 (interlobar LNs, 27.3%) and ipsilateral station 10 (hilar LNs, 25.5%).

Conclusion

Metastasis to MLNs should be considered in patients with head and neck cancer, especially in cases that are associated with a hypopharyngeal cancer, recurrent tumor, and high TNM stages.

Prognosis after Curative Resection of Single Hepatocellular Carcinoma with A Focus on LI-RADS Targetoid Appearance on Preoperative Gadoxetic Acid-Enhanced MRI

Objective

To evaluate the prognostic implications of preoperative magnetic resonance imaging (MRI) features of hepatocellular carcinoma (HCC) with a focus on those with targetoid appearance based on the Liver Imaging Reporting and Data System (LI-RADS), as well as known microvascular invasion (MVI) features.

Materials and Methods

This retrospective study included 242 patients (190 male; mean age, 57.1 years) who underwent surgical resection of a single HCC (≤ 5 cm) as well as preoperative gadoxetic acid-enhanced MRI between January 2012 and March 2015. LI-RADS category was assigned, and the LR-M category was further classified into two groups according to rim arterial-phase hyperenhancement (APHE). The imaging features associated with MVI were also assessed. The overall survival (OS), recurrence-free survival (RFS), and their associated factors were evaluated.

Results

Among the 242 HCCs, 190 (78.5%), 25 (10.3%), and 27 (11.2%) were classified as LR-4/5, LR-M with rim APHE, and LR-M without rim APHE, respectively. LR-M with rim APHE (vs. LR-4/5; hazard ratio [HR] for OS, 5.48 [p = 0.002]; HR for RFS, 2.09 [p = 0.042]) and tumor size (per cm increase; HR for OS, 6.04 [p = 0.009]; HR for RFS, 1.77 [p = 0.014]) but not MVI imaging features (p > 0.05) were independent factors associated with OS and RFS. Compared to the 5-year OS and RFS rates in the LR-4/5 group (93.9% and 66.8%, respectively), the LR-M with rim APHE group had significantly lower rates (68.0% and 45.8%, respectively, both p < 0.05), while the LR-M without rim APHE group did not significantly differ in the survival rates (91.3% and 80.2%, respectively, both p > 0.05).

Conclusion

Further classification of LR-M according to the presence of rim APHE may help predict the postoperative prognosis of patients with a single HCC.

Geometric parameters on MRA source images to differentiate small Proximal Posterior communicating artery aneurysms from Infundibular dilation

BACKGROUND AND PURPOSE

We aimed to assess the accuracy of magnetic resonance angiography (MRA) in the differentiation of small aneurysms versus infundibular dilations (IDs) at the internal carotid artery-posterior communicating artery (ICA-PComA) junction, emphasizing the role of MRA axial source images.

METHODS

This retrospective study consisted of 83 focal arterial protrusions at ICA-PComA junction in 76 patients who underwent both MRA and digital subtraction angiography (DSA)/3-dimensional rotational angiography (3DRA). The diagnostic performance of MRA for differential diagnosis of aneurysm from ID was calculated using DSA/3DRA interpretation as the standard of reference. In addition, long-axis diameter, short-axis diameter, long-axis diameter/short-axis diameter (L/S) ratio, and angle of lesion (angle of the long-axis of lesion with respect to the x-axis) measured on MRA source images were compared between aneurysms and IDs.

RESULTS

Sensitivity, specificity, and accuracy of MRA for distinguishing aneurysms from IDs were 74.4% (57.9-87.0%) to 76.9% (60.7-88.9%), 93.2% (81.3-98.6%) to 95.5% (84.5-99.4%), and 85.5% (76.1-92.3%), respectively. Significant differences were found for the long-axis diameter (P < .001), short-axis diameter (P < .001), L/S ratio (P < .05), and angle of the lesion (P < .001) on MRA axial source images between aneurysms and IDs. The angle of the lesion had the highest discriminatory ability (area under the curve = .966 [.902-.994]) to differentiate aneurysms from IDs. An angle of lesion >60° was 89.7% (75.8-97.1%) sensitive and 100% (92.0-100.0%) specific for diagnosis of aneurysm.

CONCLUSIONS

MRA is a useful imaging modality for distinguishing between aneurysm and ID at the ICA-PComA junction. Furthermore, geometric parameters on MRA axial source images can provide added value in their differentiation.

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.

Intra-parotid lymph node metastasis in patients with non-cutaneous head and neck cancers: clinical and imaging features for differentiation from simultaneous parotid primary tumor

BACKGROUND

Although uncommon, intra-parotid lymph node (IPLN) metastasis should be considered in the differential diagnosis of parotid masses in patients with head and neck cancers.

PURPOSE

To compare the clinical and imaging features of IPLN metastases from head and neck cancers and simultaneous parotid primary tumors.

MATERIAL AND METHODS

A retrospective review of 2199 patients with non-parotid head and neck cancers revealed 63 patients who also underwent parotidectomy during curative resection of head and neck cancer. After exclusion of direct extension to the parotid gland from adjacent primary tumors (n = 12) and IPLN metastases from skin cancer (n = 5), the final study group was composed of 46 patients, including 26 (1.2%) with 33 IPLN metastases and 20 (0.9%) with 24 simultaneous parotid primary tumors. We compared clinical features of patients (sex, age, site of primary tumor, histologic type, history of prior treatment for malignancy, TNM stages, side of parotid lesion, multiplicity, and metastasis in ipsilateral cervical LNs) and the CT (location in parotid gland, maximum dimension, margins, and central necrosis or cystic change) and 18F-FDG PET/CT (maximum standardized uptake value) findings.

RESULTS

Ipsilateral level II LN metastasis was more frequent in the IPLN metastasis group than in the simultaneous parotid primary tumor group (73.1% vs. 35.0%, P < 0.05). Imaging features such as location in parotid gland, maximum dimension, margins, central necrosis or cystic change, and maximum standardized uptake value showed no significant differences between the two groups.

CONCLUSION

CT and PET/CT findings of IPLN metastasis are indistinguishable from simultaneous parotid primary tumor in patients with head and neck cancers.

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.

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.

256-row multislice CT angiography in the postoperative evaluation of cerebral aneurysms treated with titanium clips: using three-dimensional rotational angiography as the standard of reference

OBJECTIVE

To assess the diagnostic accuracy of 256-row multislice computed tomographic angiography (CTA) compared with three-dimensional rotational angiography (3DRA) in the postoperative evaluation of cerebral aneurysms treated with titanium clips.

METHODS

A total of 128 patients (42 men, 86 women; mean age, 57.6 years) with 143 cerebral aneurysms treated using titanium clips underwent both CTA and 3DRA. Two reviewers retrospectively evaluated the following parameters on CTA and 3DRA: (1) residual/recurrent aneurysm (absent or present), (2) patency of parent artery (patent or occluded/severe stenotic (> 70%)), and (3) patency of adjacent branch (patent or occluded/absent).

RESULTS

A total of 24 residual/recurrent aneurysms were detected by 3DRA. The sensitivity, specificity, and accuracy of CTA for the detection of residual/recurrent aneurysms were 83.3%, 100%, and 97.2% for reviewer 1 and 79.2%, 100%, and 96.5% for reviewer 2, respectively. The sensitivity, specificity, and accuracy of CTA for the evaluation of patency of parent artery were 100%, 100%, and 100%, respectively, for both reviewers. The sensitivity, specificity, and accuracy of CTA for evaluation of the patency of adjacent branch were 85.1%, 100%, and 92.3% for reviewer 1 and 82.4%, 100%, and 90.9% for reviewer 2, respectively.

CONCLUSION

A 256-row multislice CTA is a valuable non-invasive tool for assessment of cerebral aneurysms treated with titanium clips.

KEY POINTS

• A 256-row multislice CTA is an accurate imaging technique for the postoperative assessment of cerebral aneurysms treated with titanium clips. • Sensitivity of CTA for the detection of residual/recurrent aneurysms was 79-83% compared with 3DRA. • CTA is still limited in detecting residual/recurrent aneurysms of < 2 mm and small adjacent branches.

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.

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.

Detection of loco-regional recurrence in malignant head and neck tumors: a comparison of CT, MRI, and FDG PET-CT

BACKGROUND

The early and accurate detection of local or regional recurrence of head and neck tumor is critically important.

PURPOSE

To compare the diagnostic accuracy of contrast-enhanced computed tomography (CT), contrast-enhanced magnetic resonance imaging (MRI), and fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT, alone and in combination, in detecting the locoregional recurrence of malignant head and neck tumor.

MATERIAL AND METHODS

A total of 93 patients with loco-regional recurrence of malignant head and neck tumors underwent CT, MRI, and PET-CT within 30 days before surgery. CT, MRI, and PET-CT for each patient were retrospectively reviewed to determine the presence of recurrent tumors in the primary site on a patient-by-patient basis and that of regional lymph nodes on a level-by-level basis. The diagnostic accuracy of CT, MRI, and PET-CT, alone and combined, were accessed with the postoperative histopathological findings or with 12-month follow-up results as the standard of reference.

RESULTS

The sensitivity/specificity/and accuracy of CT, MRI, and PET-CT for the detection of primary site recurrence was 89.9/85.7/89.3%, 94.9/85.7/93.6%, and 97.5/92.9/96.8%, respectively. The sensitivity/specificity/accuracy of CT, MRI, and PET-CT for the detection of nodal recurrence was 66.3/99.4/92.4%, 74.7/99.4/94.2%, and 85.5/94.9/93.0%, respectively. MRI + PET-CT achieved the best performance in the receiver operating characteristics curve analysis (Az value = 0.958 for primary site recurrence and 0.929 for nodal recurrence).

CONCLUSION

MRI + PET-CT offered the highest diagnostic performance in the detection of loco-regional recurrence of malignant head and neck tumor, compared with CT, MRI, PET-CT, and other combinations including CT.

The most mentioned neurointervention articles in online media: a bibliometric analysis of the top 101 articles with the highest altmetric attention scores

Background and purpose

Alternative metrics (altmetrics), based on mentions in online media, is a new tool that can help to identify the most influential articles to diverse public audiences. This article aimed to determine the 100 most mentioned articles in the field of neurointervention and to analyze their characteristics.

Materials and methods

We selected the 808 journals that were considered journals potentially publishing articles on neurointervention. We also selected articles using keywords. Using the Altmetric.com search tool, we identified the 101 most mentioned neurointervention articles based on the highest altmetric attention scores (AASs) within selected journals and articles. Each article was evaluated for several characteristics including AAS, number of citations, journal title, journal category, impact factor of the journal, year of publication, authorship, country, type of document, and topic.

Results

The AASs for the top 101 articles ranged from 1586 to 39. Stroke published the largest number of articles (19.8%) followed by the New England Journal of Medicine (17.8%). The majority of articles were published in multidisciplinary journals (38.6%), were published in 2017–2018 (43.6%), originated from the USA (54.5%), were original articles (66.3%), and dealt with intra-arterial thrombolysis or thrombectomy for acute ischemic stroke (58.4%). Tudor G Jovin was the most prolific author, authoring 18 of the most mentioned neurointervention articles

Conclusions

This study presents a detailed list of the 101 most mentioned neurointervention articles in online media, thus providing useful information on the dissemination of neurointervention research to the general public.

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.

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 Most-Cited Articles Focused on Ultrasound Imaging: A Bibliometric Analysis

Purpose The number of citations that an article has received reflects its impact on a particular research area. The aim of this study was to identify the 100 most-cited articles focused on ultrasound (US) imaging and to analyze the characteristics of these articles. Methods We determined the 100 most-cited articles on US imaging via the Web of Science database, using the search term. The following parameters were used to analyze the characteristics of the 100 most-cited articles: publication year, journal, journal impact factor, number of citations and annual citations, authors, department, institution, country, type of article, and topic. Results The number of citations for the 100 most-cited articles ranged from 1849 to 341 (median: 442.0) and the number of annual citations ranged from 108.0 to 8.1 (median: 22.1). The majority of articles were published in 1990 - 1999 (39 %), published in radiology journals (20 %), originated in the United States (45 %), were clinical observation studies (67 %), and dealt with the vessels (35 %). The Department of Internal Medicine at the University of California and the Research Institute of Public Health at the University of Kuopio (n = 4 each) were the leading institutions and Salonen JT and Salonen R (n = 4 each) were the most prolific authors. Conclusion Our study presents a detailed list and analysis of the 100 most-cited US articles, which provides a unique insight into the historical development in this field.

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.

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.

Characteristics and trends of research on positron emission tomography: a bibliometric analysis, 2002-2012

OBJECTIVE

We performed a bibliometric analysis of scientific publications focused on positron emission tomography (PET) over a 10-year period.

METHODS

The MEDLINE and ISI Web of Knowledge databases were searched for English language original articles focused on PET in SCI/SCIE-indexed journals in 2002, 2007, and 2012. We selected the documents with titles that included "PET" or "positron emission." The following information was obtained from each article: journal (year of publication, title, subject category, and impact factor), subspecialty, imaging modality used, tracer, species, sample size, number of authors, affiliation of the first author, declared funding, and country of origin.

RESULTS

The yearly publication on PET increased from 547 (2002) to 986 (2007), and 1838 (2012). A total of 1753 (52.0%) articles were published in journals in the "Radiology, Nuclear Medicine & Medical Imaging" category, 1512 (44.9%) were in the subspecialty of oncology, 3245 (96.3%) used PET or PET/CT, 1698 (50.4%) used 2-fluoro-2-deoxy-D-glucose (FDG) as the radiotracer, 2378 (70.5%) were human studies, 1294 (38.4%) had a sample size of <20, 1674 (49.7%) had >7 authors, 779 (23.1%) were written by a first author from a department of nuclear medicine, and 1337 (39.7%) were supported by government funding. The United States published 948 studies (28.1%) followed by Japan (345, 10.2%) and Germany (335, 9.9%). In the time trend analysis oncology subspecialty, PET/MR as the imaging modality, FDG as the tracer, sample size>50, number of authors>7, radiology department affiliation of the first author, and government funding exhibited significantly positive trends.

CONCLUSIONS

The number of publication concerning PET has increased rapidly over the last decade. This bibliometric analysis revealed characteristics and trends of current PET research that provides useful information to researchers.

Incidental thyroid lesions identified by ultrasound in patients with non-thyroidal head and neck cancer

BACKGROUND

Thyroid cancer is one of the common head and neck malignancies and may be found incidentally with other head and neck cancers.

PURPOSE

To evaluate the prevalence and risk of malignancy in incidental thyroid lesions identified by ultrasound (US) in patients with head and neck cancer.

MATERIAL AND METHODS

We retrospectively reviewed medical records of all patients with head and neck cancer other than of thyroid origin between January 2004 and December 2011. A total of 690 patients (537 men and 153 women; mean age, 58.9 ± 12.9 years) underwent US of the neck for the evaluation of cervical lymph node status (including thyroid gland). We evaluated the prevalence of patients with incidental thyroid lesions identified by US and the risk of malignancy in these patients.

RESULTS

Of the 690 patients with head and neck cancer, 234 (33.9%) had incidental thyroid lesions on US. Based on US findings, 61 patients underwent fine-needle aspiration, with 39 eventually undergoing thyroidectomy. Among these thyroid lesions, 24 incidental thyroid lesions of 22 patients were histologically proven to be malignant (23 papillary and 1 follicular carcinomas). The risk of malignancy was 9.4% on a patient-by-patient basis.

CONCLUSION

Screening of the thyroid gland should be included in the preoperative US examination for cervical lymph node metastases in patients with non-thyroidal head and neck cancer.

Thrombophlebitis of the internal jugular vein (Lemierre syndrome): clinical and CT findings

BACKGROUND

Thrombophlebitis of the internal jugular vein (IJV) secondary to neck infection (so-called Lemierre syndrome) is a rare disease.

PURPOSE

To evaluate the clinical and CT findings in patients with thrombophlebitis of the IJV.

MATERIAL AND METHODS

The clinical and contrast-enhanced neck CT findings were retrospective analyzed in 10 patients (eight men, two women; mean age, 62.9 ± 8.3 years) with thrombophlebitis of the IJV.

RESULTS

Five patients (50%) had complications, including pneumonia (n = 3), neck abscess (n = 1), and thrombophlebitis of cerebral venous sinus (n = 1). All patients, except two who were lost to follow-up, had improved after antibiotics and anticoagulation therapy. Nine (90%) patients had underlying infectious processes in the neck. Contrast-enhanced neck CT of 12 IJVs (five right, three left, and two bilateral) affected by thrombophlebitis demonstrated > 5 cm in length (n = 8, 67%), ovoid shape (n = 7, 58%), complete occlusion of the lumen (n = 10, 83%), circumferential (n = 11, 92%), smooth (n = 8, 67%), and thick (≥4 mm) (n = 8, 67%) rim enhancement, and adjacent soft tissue swelling (n = 11, 92%).

CONCLUSION

Contrast-enhanced CT is useful in the diagnosis of thrombophlebitis of the IJV; characteristic CT findings of this unusual entity may be the main clue to the correct diagnosis.

Korea's contribution to radiological research included in Science Citation Index Expanded, 1986-2010

OBJECTIVE

To evaluate scientific papers published by Korean radiologists in the Science Citation Index Expanded (SCIE) radiology journals, between 1986 and 2010.

MATERIALS AND METHODS

The Institute for Scientific Information Web of Knowledge-Web of Science (SCIE) database was searched for all articles published by Korean radiologists, in SCIE radiology journals, between 1986 and 2010. We performed the analysis by typing "Korea" and "radiol" in the address section and selecting the subject area of "Radiology, Nuclear Medicine, and Medical Imaging" with the use of the general search function of the software. Analyzed parameters included the total number of publications, document types, journals, and institutions. In addition, we analyzed where Korea ranks, compared to other countries, in terms of the number of published articles. All these data were analyzed according to five time periods: 1986-1990, 1991-1995, 1996-2000, 2001-2005, and 2006-2010.

RESULTS

Overall, 4974 papers were published by Korean radiologists, in 99 different SCIE journals, between 1986 and 2010, of which 4237 (85.2%) were article-type papers. Of the total 115395 articles, worldwide, published in radiology journals, Korea's share was 3.7%, with an upward trend over time (p < 0.005). The journal with the highest number of articles was the American Journal of Roentgenology (n = 565, 13.3%). The institution which produced the highest number of publications was Seoul National University (n = 932, 22.0%).

CONCLUSION

The number of scientific articles published by Korean radiologists in the SCIE radiology journals has increased significantly between 1986 and 2010. Korea was ranked 4th among countries contributing to radiology research during the last 5 years.

Relationship between the risk of bile duct injury during laparoscopic cholecystectomy and the types of preoperative magnetic resonance cholangiopancreatiocography (MRCP)

Backgrounds/Aims

Bile duct injury is one of the potential severe complications that can occur during laparoscopic cholecystectomy, which can be cause by anatomic variations in the confluence of the bile duct. Recently magnetic resonance cholangiopancreatiocography (MRCP) has become a helpful tool to detect bile duct variation on a preoperative basis and to prevent bile duct injury during laparoscopic cholecystectomy, as well other hepatic surgeries. This study aimed to clarify the types of bile duct on MRCP and to search for a method of avoiding injury during laparoscopic cholecystectomy.

Methods

Between January 2009 and December 2010, 277 patients underwent laparoscopic cholecystectomy with preoperative MRCP in our institution. On a retrospective basis, the bile ducts were categorized into 5 types according to the Couinaud classification system.

Results

The proportion of types was revealed type A (70.4%), type B (8.7%), type C (19.5%), type D (0.7%), type E (0%), and type F (0.7%), respectively. Bile duct injury occurred in 4 cases (1.4%) during laparoscopic cholecystectomy. In particular, the possibility of aberrant extrahepatic confluence (Type C and F) represented the highest risk of duct injury (OR=11.89 [CI: 1.21-116.53]).

Conclusions

Preoperative evaluation of the bile duct anatomy is important to avoid injury of duct during laparoscopic cholecystectomy. Specific types of bile duct variation should be considered as a high risk group for bile duct injury.

Calcified carcinoma of the gallbladder with calcified nodal metastasis presenting as a porcelain gallbladder: a case report

Porcelain gallbladder is regarded as a risk factor of gallbladder cancer. A porcelain gallbladder with calcified regional lymph nodes was found using computed tomography (CT) and magnetic resonance imaging (MRI) in a 43-year-old man who presented with nausea, vomiting, and abdominal pain. His cholecystectomy specimen showed diffuse wall thickening and contained small gallstones. Histological examination revealed diffuse infiltrative adenocarcinoma with extensive intratumoral calcification (calcified carcinoma). The majority of the calcified material was located within or replaced the tumor glands, and was not found in the stroma. A lymph node was totally replaced with a calcified metastatic adenocarcinoma. To the best of our knowledge, only one case of calcified lymph node metastasis from a calcified carcinoma of the gallbladder has been previously reported in the literature. We herein add a case of calcified carcinoma of the gallbladder with calcified lymph node metastasis, presenting as a porcelain gallbladder on CT and MRI.

CT, MR, (18)F-FDG PET/CT, and their combined use for the assessment of mandibular invasion by squamous cell carcinomas of the oral cavity

BACKGROUND

a reliable assessment of mandibular invasion is crucial for treatment planning to obtain both radical tumor resection and good functional results.

PURPOSE

to retrospectively compare the diagnostic value of three different imaging methods - computed tomography (CT), magnetic resonance (MR) imaging, (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT - and their combined use for detection of mandibular invasion by squamous cell carcinoma (SCC) of the oral cavity.

MATERIAL AND METHODS

forty-six patients (39 men and 7 women; mean age, 59.4 years) suspected of having mandibular invasion by SCC of the oral cavity underwent CT, MR, and PET/CT within 2 weeks before surgery. First, each study was reviewed separately for the presence of mandibular invasion by tumors. Then, the value of combined images was assessed based on a confidence rating score for each modality assigned by observers. These results were verified with histopathologic findings.

RESULTS

HIstopathologic examination revealed mandibular invasion in 12 of 46 SCCs. The sensitivity, specificity, and accuracy were 41.7%, 100%, and 84.8% for CT; 58.3%, 97.1%, and 87.0% for MR; and 58.3%, 97.1%, and 87.0% for PET/CT, respectively. The comparison of these modalities showed no statistically significant difference among them (P > 0.05). The combination of CT, MR, and PET/CT improved sensitivity (83.3%), without loss of specificity (100%) and accuracy (95.7%), although the difference failed to reach statistical significance (P > 0.05).

CONCLUSION

the combined analysis of CT, MR, and PET/CT can improve sensitivity in the detection of mandibular invasion by SCC of the oral cavity.

CT features of foreign body granulomas after cosmetic paraffin injection into the cervicofacial area

PURPOSE

Cosmetic injection of paraffin into cervicofacial tissues has been practiced in the past, especially in Asia, resulting in foreign body granuloma (paraffinoma). The purpose of this study was to describe the computed tomography (CT) findings of cervicofacial paraffinomas.

MATERIALS AND METHODS

CT images of 5 patients (4 women and 1 man; age range, 54-80 years; mean age, 67.6 years), who had received direct paraffin injections into cervicofacial tissues, were reviewed retrospectively.

RESULTS

The lesions were bilateral and located in the subcutaneous fat layer of the cheek (n = 5), buccal space (n = 2), periorbital area (n = 1), periauricular area (n = 1), neck (n = 1), and nose (n = 1). The predominant CT features were speckled mass formation (n = 3), fat-density nodule (n = 5), high-density nodule (n = 5), nodular calcification (n = 5), and rim calcification (n = 4).

CONCLUSION

Paraffinomas in the cervicofacial region have specific CT features that are distinct from other soft tissue masses.

CT, MR, and angiography findings of a solitary fibrous tumor of the larynx: a case report

This report details the CT, MR, and angiography findings of a solitary fibrous tumor involving the larynx of a 34-year-old man. A precontrast CT scan revealed a well-defined isodense mass in the submucosal region of the supraglottic larynx. The tumor appeared as a mixed intensity lesion on the T1- and T2-weighted MR images. A T2-weighted MR image showed a central, round, and low signal intensity area within the mass. For both the CT and MR images, the mass demonstrated heterogeneous enhancement following the administration of contrast material. The angiography showed a hypervascular tumor with heterogeneous persistent staining.

Publication rates for abstracts presented by Korean investigators at major radiology meetings

Objective

To determine the publication rate of abstracts presented by Korean investigators at national and international radiological meetings, and to identify predictive factors of publication.

Materials and Methods

Abstracts presented at the annual meetings of the Korean Radiological Society (KRS), and abstracts presented by Korean investigators at the annual meetings of the Radiological Society of North America (RSNA) and European Congress of Radiology (ECR) from 2001 to 2002 were searched for subsequent publication, using PubMed and the Korean Medical Database. The following variables were evaluated. 1) The overall publication rate; 2) the publication rates according to the radiological subspecialty, presentation type (oral or poster), sample size (≤ 20, 21-50, or > 50), study design (prospective or retrospective), statistical analysis (present or absent), and study outcome (positive or negative); 3) the time to publication; 4) the journal where the study was published; 5) consistency between the abstract and the final publication.

Results

Of 1,097 abstracts, 301 (27.4%) were subsequently published, at an average of 15.8 ± 13.8 months after presentation in 48 journals. The publication rates for studies presented at the RSNA (35.4%) and ECR (50.5%) conferences were significantly higher than that for the KRS conference (23.6%, p < 0.05). Vascular/interventional radiology studies had the highest publication rate (33.1%), whereas musculoskeletal radiology studies had the lowest publication rate (17.1%). Other factors associated with subsequent publication were prospective design, use of statistical testing, and a positive study outcome.

Conclusion

The publication rate is significantly lower for the KRS (23.6%) meeting abstracts as compared to those of the RSNA (35.4%) and ECR (50.5%). Prospective design, use of statistical testing, and positive study outcome have a statistically significant effect on the publication rate.

Anaplastic thyroid carcinoma: computed tomographic differentiation from other thyroid masses

BACKGROUND

Anaplastic thyroid carcinoma is rare but is one of the most aggressive malignancies. Therefore, accurate diagnosis is important in order to provide appropriate therapy.

PURPOSE

To establish useful computed tomographic (CT) criteria for differentiating anaplastic carcinoma from other thyroid masses.

MATERIAL AND METHODS

The CT scans of nine patients with anaplastic carcinomas were retrospectively reviewed and compared with those of 32 patients with papillary carcinomas (n = 12) or benign lesions (n = 20) exceeding a maximum diameter of 2.0 cm. Image analysis was performed according to the following CT parameters: size, margin (well defined or ill defined), composition (cystic, mixed, or solid), mean attenuation value, ratio of attenuation of the mass to that of the adjacent muscle (M/m attenuation ratio), necrosis (present or absent), and calcification (stippled, nodular, or absent) of the thyroid mass; and tumor-spreading patterns including the presence of surrounding normal thyroid tissue in the involved lobe, involvement of the contralateral thyroid lobe, extension into the adjacent structures, and cervical lymphadenopathy.

RESULTS

Anaplastic carcinomas appeared as large (average 4.6 cm), solid (100%), and ill-defined (88.9%) masses accompanied by necrosis (100%), nodular calcification (44.4%), direct invasion into the adjacent organs (55.6%), and cervical lymph node involvement (77.8%). Tumor necrosis was the most valuable parameter in differentiating anaplastic carcinomas from other thyroid masses. Patient age (>70 years) and low attenuation value on postcontrast scan (attenuation value <100 HU, or M/m attenuation ratio <1.3) are also helpful predictors for anaplastic carcinoma.

CONCLUSION

If a patient is older than 70 years of age and has a large necrotic thyroid mass of low attenuation, anaplastic carcinoma should be included in the differential diagnosis.

Comparison of low-dose CT and MR for measurement of intra-abdominal adipose tissue: a phantom and human study

RATIONALE AND OBJECTIVES

The aim of this study was to determine the accuracy and reproducibility of low-dose computed tomography (CT) and magnetic resonance (MR) for abdominal adipose tissue quantification on phantom and human studies.

MATERIALS AND METHODS

An adiposity phantom (with known internal/external oil volumes) was scanned at three different tube voltages (140, 120, and 90 kVp) using a 16-detector row CT scanner and was imaged using a T1-weighted spin echo MR sequence. For human studies, whole-volume coverage of the abdomen was obtained using CT (at 140 and 90 kVp) and T1-weighted spin echo MR imaging from five obese male volunteers (mean age, 40.6 years; mean body mass index, 30.2). The volumes of total, visceral, and subcutaneous adipose tissues (TAT, VAT, and SAT, respectively) were calculated independently by two radiologists for each CT scan and MR imaging using a computer-aided semiautomatic program.

RESULTS

The estimated radiation dose could be reduced by approximately 75% with a 90-kVp protocol as compared with the 140-kVp protocol. Phantom studies showed that there was no statistically significant difference between the four methods in estimating the percentage predicted of the true volumes (measurement errors <4% for all methods, P > .05). In human studies, we found no statistically significant difference between the three methods in TAT, VAT, and SAT volumes (P > .05). Inter- and intraobserver reproducibilities of the CT volume estimates using the 90-kVp protocol were better than those obtained from MR imaging (kappa > 0.9 versus 0.4-0.5; coefficient of variation < 1% versus 15-22%).

CONCLUSION

Low-dose CT provides accurate and reproducible measurement of abdominal adipose tissue volumes with a relevant dose reduction.

Peripheral calcification in thyroid nodules: ultrasonographic features and prediction of malignancy

OBJECTIVE

The purpose of this study was to investigate the association between peripheral calcification in thyroid nodules detected on ultrasonography and thyroid malignancy.

METHODS

We retrospectively analyzed the ultrasonographic features of 65 pathologically proven thyroid lesions showing peripheral calcification for their correlation with histopathologic results. The following ultrasonographic parameters were assessed for each nodule: size (maximal dimension), shape (anteroposterior dimension/transverse dimension ratio), internal echogenicity (hypoechoic, isoechoic, hyperechoic, or invisible), halo sign (present or absent), type of calcification (stippled, curvilinear/smooth margin, or curvilinear/irregular margin), and extent of calcification (arc or rim).

RESULTS

Twelve (18.5%) of 65 thyroid nodules with peripheral calcification were malignant, and 53 (81.5%) were benign. Patient demographics (age and sex) and ultrasonographic features of the nodules (size, shape, internal echogenicity, halo sign, and type and extent of calcification) did not show any significant differences between benign and malignant groups.

CONCLUSIONS

The relatively high prevalence of malignancy and no reliable criterion for malignancy in thyroid nodules with peripheral calcification indicate that fine-needle aspiration or careful ultrasonographic follow-up may be warranted in these cases.

Sixteen-Detector Row CT Angiography of the Brain

OBJECTIVE

The aim of this prospective study was to investigate the effect of different volumes of contrast material on vascular enhancement in 16-channel multi-detector row computed tomographic angiography of the brain.

METHODS

A total of 194 patients were divided into 3 groups who received different volumes of contrast material: 100 (n = 62), 80 (n = 72), and 60 mL (n = 60). The attenuation values were measured on transverse images at 12 different intracranial vessels (right and left internal carotid arteries, A2s, M2s, and P2s, basilar artery, vein of Galen, superior sagittal sinus, and dominant sigmoid sinus). The image quality parameters (intra-arterial contrast, arterial delineation, venous contamination, and confidence in diagnosis) were graded by 2 observers in consensus using a 5-point scale.

RESULTS

The attenuation values at the left A2 segment, superior sagittal sinus, and sigmoid sinus were significantly lower in the 60-mL group than those in other groups, whereas no significant differences were found between the 3 groups for the remaining intracranial vessels. For qualitative evaluation, arterial delineation was rated higher in the 100- and 80-mL groups, whereas less venous contamination was found in the 60-mL group. There was no significant difference in overall image quality (the sum of the scores for 4 image quality parameters) between the 3 groups.

CONCLUSIONS

A contrast material volume of 60 mL (18 g iodine) provides excellent image quality of cerebral multi-detector row computed tomographic angiography comparable to those achievable with 100 and 80 mL.

Effects of Right- Versus Left-Arm Injections of Contrast Material on Computed Tomography of the Head and Neck

OBJECTIVE

To investigate the effects of the right- and left-arm injections of contrast material on image quality in computed tomography of the head and neck.

METHODS

Sixty patients were prospectively and randomly assigned into 2 groups. Eighty milliliters of contrast material (iodine concentration, 300 mg/mL) was administered into the right (n = 30) or the left (n = 30) antecubital vein at a 2-mL/s injection rate. The attenuation of the carotid artery (CA) and the internal jugular vein (IJV) was measured at 1.5-second intervals in each patient. The mean attenuation values for CA and IJV, the time to reach peak attenuation, the duration of diagnostic window (both CA and IJV enhancement were greater than 150 HU), the perivenous artifacts, and the retrograde flow of contrast material column from the subclavian or brachiocephalic vein were statistically compared between patients with right-arm injection and those with left-arm injection.

RESULTS

The mean attenuation values in CA and IJV were slightly higher in patients with right-arm injection than in those with left-arm injection, although no significant difference was reached (P = 0.06 for CA and 0.07 for IJV). The right-arm injection resulted in significantly reduced perivenous artifacts and retrograde flow of contrast material column. There were no significant differences in the time to reach the peak attenuation and in the duration of the diagnostic window between the 2 groups.

CONCLUSIONS

The right-arm injection of contrast material may provide better image quality in the computed tomography of the head and neck when compared with the left-arm injection.

Factors affecting the serum levels of adipokines in Korean male patients with nonalcoholic fatty liver disease

BACKGROUND/AIMS

Adipokines are associated with various metabolic disorders including insulin resistance, obesity, and dyslipidemia. Metabolic disorders have also been reported to be associated with nonalcoholic fatty liver disease (NAFLD). The aim of this study was to determine the relationship between the serum adipokine levels and the degrees of hepatic fat infiltration in NAFLD. This study also attempted to determine the independent factors influencing the serum adipokine levels in NAFLD.

METHODOLOGY

Sixty-five Korean male patients were enrolled in this study. The degree of hepatic fat infiltration was classified into the following three groups according to the ultrasonographic findings: Group I, normal liver; Group II, mild fatty liver; and Group III, moderate to severe fatty liver. The anthropometric parameters, fasting serum adipokine levels including leptin, adiponectin and resistin were measured in all subjects. The level of insulin resistance was estimated using the HOMA-IR.

RESULTS

The serum leptin levels increased with increasing degree of hepatic fat infiltration (mean +/- SD: Group I, 2.052 +/- 1.071; Group II, 2.879 +/- 1.016; and Group III, 4.457 +/- 1.965 ng/mL, P < 0.001). However, the serum adiponectin and resistin levels were similar. The fasting serum insulin level was only a related factor for the changes in the serum leptin levels (P = 0.004). There were no related factors for the change in the serum adiponectin and resistin levels.

CONCLUSIONS

This study suggests an indirect role for leptin in the pathogenesis of NAFLD by inducing insulin resistance, resulting in increased fasting serum insulin level.

Changes in the abdominal fat distribution after gastrectomy: computed tomography assessment

BACKGROUND

We investigated the postoperative changes in visceral fat, as compared with subcutaneous fat in patients who underwent total gastrectomy (TG) or subtotal gastrectomy (STG).

METHODS

Thirty-eight patients of gastric cancer who underwent abdominal and pelvic computed tomography scans before and after STG (n = 28) or TG (n = 10) were examined. The volumes of the total, visceral and subcutaneous adipose tissues (TAT, VAT and SAT, respectively) were calculated in each scan using the multislice method. Changes between the preoperative data and results obtained at 6 and 12 months after surgery were evaluated.

RESULTS

In the first 6 months, there were significant decreases in TAT, VAT and SAT values in the TG (-2424 +/- 1309, -1535 +/- 1056 and -889 +/- 613 cm(3), respectively) and STG (-1590 +/- 1309, -1024 +/- 645, and -578 +/- 659 cm(3), respectively) groups. From 6 to 12 months after surgery, a further significant reduction in VAT (-351 +/- 196 cm(3)) in the TG group and significant regains in TAT and SAT (850 +/- 1205 and 757 +/- 1032 cm(3), respectively) in the STG group were observed. The ratio of VAT to SAT calculated in both groups decreased continuously in all periods of observation.

CONCLUSION

Patients who underwent gastrectomy lost TAT, VAT and SAT during the postoperative period up to 6 months and the decrease in VAT was greater and more persistent than the decrease in SAT, particularly in the TG group.

Identification of adiponectin and its receptors in human osteoblast-like cells and association of T45G polymorphism in exon 2 of adiponectin gene with lumbar spine bone mineral density in Korean women

OBJECTIVE

The role of adiponectin in bone metabolism has been recently reported in in vitro and in vivo studies. There has been no report on the association of adiponectin gene polymorphism and bone mineral density (BMD). Therefore, we investigated whether two single nucleotide polymorphisms (SNPs), T45G and G276T, in the adiponectin gene were related to BMD in Koreans. We also report on the identification of adiponectin and its receptors 1 and 2 in human osteoblast-like cell lines.

PATIENTS AND MEASUREMENTS

MG-63 cells were cultured and osteogenic and adipogenic differentiations from human mesenchymal stem cells (hMSCs) were performed. RNA was then extracted from the cultured cells and reverse transcriptase-polymerase chain reaction (RT-PCR) was performed using primers for adiponectin and for the adiponectin receptor genes. In 249 female and 80 male subjects, measurements were made of their lumbar spine and femoral neck BMDs, and biochemical markers of bone turnover. The genotyping of the T45G polymorphism in exon 2 and the G276T polymorphisms in intron 2 in the adiponectin gene was performed using an allelic discrimination assay with a TaqMan probe. Analyses were performed separately in each cohort.

RESULTS

We found that the mRNAs for adiponectin and for adiponectin receptor 1 (AdipoR1) and 2 (AdipoR2) were expressed in the MG-63 cells. Sequencing of the PCR products revealed that they were identical to human adiponectin, AdipoR1 and AdipoR2, respectively. mRNAs for adiponectin, AdipoR1 and AdipoR2 were also expressed in the osteoblastic and adipogenic cell lines differentiated from hMSCs. For the polymorphism study, the frequencies of T45G and G276T in the adiponectin gene were in compliance with Hardy-Weinberg equilibrium and the two polymorphisms were in complete linkage disequilibrium (D' = -1.0, P < 0.001). In the female cohort, subjects with G alleles at the T45G locus had significantly lower lumbar spine BMD than those subjects with the TT genotype. Although BMD levels showed no association with the G276T locus, the GT genotype group showed significantly higher urine deoxypyridinoline levels than other genotype groups. In the male cohort, no association was observed between adiponectin genotypes and BMD levels.

CONCLUSIONS

We observed the expression of adiponectin, AdipoR1 and AdipoR2 in the MG-63 cell line and the osteoblastic cell line differentiated from hMSCs. T45G polymorphism in exon 2 of the adiponectin gene is associated with lumbar spine BMD and G276T polymorphism in intron 2 of the adiponectin gene is associated with the urine deoxypyridinoline level in Korean women. Additional studies are needed to elucidate the precise contribution of adiponectin to bone mineral metabolism.

Multi-detector row CT of the head and neck: comparison of different volumes of contrast material with and without a saline chaser

INTRODUCTION

The aim of this study was to determine the effect of different volumes of contrast material with and without a saline chaser on tissue enhancement in multidetector row CT (MDCT) of the head and neck.

METHODS

In a blind prospective fashion, 120 patients were randomized into the following four groups: group 1, 80 ml contrast material administered at a flow rate of 2.0 ml/s; group 2, 80 ml followed by 40 ml saline at 2.0 ml/s; group 3, 60 ml at 1.5 ml/s; and group 4, 60 ml followed by 30 ml saline at 1.5 ml/s. The attenuation values of the carotid artery, internal jugular vein, and muscle were measured at an interval of 1.5 s in each patient. The degree of perivenous artifacts was subjectively assessed.

RESULTS

Mean attenuation values in the carotid artery and internal jugular vein were significantly higher in groups 1 and 2 than in groups 3 and 4. The width of the diagnostic window (both carotid and jugular enhancement >150 HU) were significantly longer in groups 1 and 2 than in groups 3 and 4. The addition of a saline chaser did not result in improved vascular enhancement or a wider diagnostic window, but reduced perivenous artifacts, compared with using contrast material alone.

CONCLUSION

Reduction of contrast material from 80 to 60 ml results in insufficient enhancement of neck vessels. In addition, the benefit of a saline chaser technique is not obvious except for its ability to reduce perivenous artifacts.

Relationship between polymorphisms G395A in promoter and C1818T in exon 4 of the KLOTHO gene with glucose metabolism and cardiovascular risk factors in Korean women

BACKGROUND

Recently, klotho has been proposed as a link between cardiovascular diseases and premature aging, but the relationship between KLOTHO genes and cardiovascular risk factors, especially glucose metabolism, in humans is unclear.

OBJECTIVES

We investigate the relationship between polymorphisms G395A in promoter and C1818T in exon 4 of the KLOTHO gene with glucose metabolism and cardiovascular risk factors in Korean women.

MATERIAL AND METHODS

In 251 women (mean age 51.3+/-6.9 yr), body mass index (BMI), waist circumference, blood pressure, fasting plasma glucose, insulin and lipid profiles were measured. The genotyping of polymorphisms G395A in promoter and C1818T in exon 4 of the KLOTHO gene was performed by allelic discrimination using a 5' nuclease polymerase chain reaction assay.

RESULTS

Allele frequencies of G395A polymorphism was 0.829 for the G allele and 0.171 for the A allele and allele frequencies of C1818T polymorphism were 0.804 for the C allele and 0.196 for the T allele, both of which were in compliance with Hardy-Weinberg equilibrium and the two polymorphisms were in linkage disequilibrium (D'=0.43, p<0.01). Mean systolic blood pressure was significantly higher in A allele carriers of G395A polymorphism compared with non-carriers, and the significance was persistent even after adjustment for age and BMI. Mean fasting plasma glucose was significantly higher in T allele carriers of C1818T polymorphism compared with non-carriers, and the significance was persistent even after adjustment for age and BMI. Subjects without any minor allele from either single nucleotide polymorphisms (SNP) had significantly lower mean values for systolic, diastolic blood pressure and fasting plasma glucose levels compared with subjects with both minor allele from either SNP.

CONCLUSIONS

We observed that KLOTHO G395A polymorphism was associated with blood pressure and KLOTHO C1818T polymorphism was associated with glucose metabolism in Korean women. Further studies are needed to clarify this relationship.

[The relationship between serum adiponectin level and serum alanine aminotransferase elevation in Korean male with nonalcoholic fatty liver disease]

BACKGROUND/AIMS

Nonalcoholic fatty liver disease (NAFLD) comprises a large part of chronic liver diseases. Recently it was reported that adipokines are closely associated with the common risk factors for NAFLD, such as obesity, diabetes, dyslipidemia, and insulin resistance. We aimed to evaluate the changes in serum adiponectin, resistin and leptin concentrations related to alanine aminotransferase (ALT) elevations in Korean men with NAFLD.

METHODS

We studies 38 men who were diagnosed with fatty liver by abdominal ultrasonography. None had a history of excessive alcohol consumption, autoimmune hepatitis, inherited or metabolic liver disease or viral hepatitis. The subjects were divided into two groups. One group had normal levels of ALT (n=28) and the other had increased ALT (n=10). We compared anthropometrical parameters, biochemical items and serum adipokine levels between these two groups.

RESULTS

Serum adiponectin levels were lower in the increased ALT group than in the normal ALT group (3.89 +/- 1.77 vs 7.01 +/- 2.54 microgram/dL, P=0.001). But there were no significant differences in serum leptin and resistin levels between two groups (4.02 +/- 2.04 vs 3.26 +/- 1.41 ng/mL, p=0.245, 80.14 +/- 14.8 vs 80.5 +/- 11.34 ng/mL, P=0.937, respectively). Multiple linear regression analyses demonstrated that the serum adiponectin level is inversely correlated with serum ALT level and that the serum aspartate aminotransferase (AST) level is positively correlated with the serum ALT level.

CONCLUSIONS

Our study shows that hypoadiponectinemia is associated with an ALT elevation in patients with NAFLD. Adiponectin may play an indirect role in the development of NAFLD.

The relationship between four single nucleotide polymorphisms in the promoter region of the osteoprotegerin gene and aortic calcification or coronary artery disease in Koreans

OBJECTIVE

Osteoprotegerin (OPG) is a recently identified cytokine that acts as a decoy receptor for the receptor activator of the NF-kappaB ligand (RANKL). OPG has been shown to be an important inhibitor of osteoclastogenesis and arterial calcification in animal models. OPG has been proposed as a link molecule between osteoporosis and arterial calcification, but the relationship between the OPG gene and the cardiovascular system in human populations is unclear. Thus, the aim of this study was to investigate the relationship between OPG gene polymorphisms and aortic calcification or coronary artery disease in Koreans.

DESIGN AND PATIENTS

Genotyping of four polymorphisms, A163G, G209A, T245G and T950C, in the promoter region of the OPG gene was performed in 251 healthy Korean women (mean age 51.3 +/- 6.9 years) and in a second study population consisting of 100 patients who underwent coronary angiography (mean age 57.0 +/- 11.9 years), by allelic discrimination using the 5' nuclease polymerase chain reaction assay. Cardiovascular risk factors and serum OPG levels were measured and aortic calcification in thoracic and abdominal aorta was examined by simple radiological methods.

RESULTS

In the first study population, the prevalence of aortic calcification increased significantly as the subjects grew older. The frequencies of mutant alleles were significantly higher in the subjects with aortic calcification compared with those without aortic calcification in G209A and T950C polymorphisms, although these significances were lost after adjustment for age. No significant relationship was found between OPG gene polymorphisms and serum OPG levels or cardiovascular risk factors. In the second study group, there were no associations between OPG promoter genotypes and aortic calcification, serum OPG levels, or coronary artery disease.

CONCLUSIONS

We observed that the four polymorphisms in the promoter region of the OPG gene were not associated with aortic calcification or coronary artery disease in Koreans. Further studies are needed to clarify this relationship.

Relationship between Subclinical Thyroid Dysfunction and Femoral Neck Bone Mineral Density in Women

BACKGROUND

Osteoporosis associated with thyroid dysfunction has been traditionally viewed as a secondary consequence of altered thyroid function, but there was recently a report about the direct effects of thyroid-stimulating hormone (TSH) on bone remodeling, which was mediated via the TSH receptor found on osteoblast and osteoclast precursor cells. Endogenous subclinical thyroid dysfunction seems to be an appropriate model to examine the direct effect of TSH on bone metabolism while ruling out the direct effect of thyroid hormone on bone metabolism. Thus, we aimed to investigate the relationship between subclinical thyroid dysfunction and bone mineral metabolism in women.

METHODS

We enrolled 413 women (mean age: 52.2 +/- 6.6 years) in our study. Serum levels of TSH, free T4 and the biochemical markers of bone turnover were measured by the standard methods. BMD at the lumbar spine and femoral neck were measured by dual energy X-ray absorptiometry.

RESULTS

Femoral neck BMD was significantly reduced both in the subclinical hyperthyroid group and in the subclinical hypothyroid group as compared with the euthyroid group (one-way ANOVA, p <0.001; post-hoc analysis, p = 0.041, p = 0.033). In contrast to the femoral neck BMD, the lumbar spine BMD showed no difference between the two groups. Additionally, serum calcium and alkaline phosphatase levels, urine deoxypyridinoline levels, and urine calcium to creatinine ratio showed no differences between the two groups.

CONCLUSIONS

Women having subclinical hyperthyroidism and women with subclinical hypothyroidsm have reduced femoral neck BMD. Additional studies are required to elucidate the mechanism for this finding.

[A case of peritoneal mesothelioma without a history of asbestos exposure]

Peritoneal mesothelioma is an unusual disease which diffusely involves the peritoneal surface. The incidence is approximately one per 1,000,000, and one fifth to one third of all mesothelioma are peritoneal in origin. Asbestos exposure is linked to the development of peritoneal mesothelioma as a significant etiology, but further investigation should be conducted. Abdominal sonography, abdominal CT and cytologic examination of ascitic fluid are used to confirm the diagnosis, but rarely provides proper diagnosis. Laparoscopy with biopsy is the most common diagnostic method for definite diagnosis of mesothelioma. Cytoreductive surgery and intraperitoneal chemotherapy have been suggested for better survival since the median survival after the initial diagnosis is near to 50 months. This report describes a case of 73-years-old male patient presented with abdominal pain and distension. This patient had not been exposed to asbestos. Abdominal sonography and CT showed massive ascites, multiple omental masses and peritoneal thickening. It was difficult to distinguish peritoneal mesothelioma from carcinomatosis. Laparoscopy and peritoneal biopsy was conducted and immunostaining examination confirmed the diagnosis of peritoneal mesothelioma.

Benign Breast Diseases Associated With Cyclosporine Therapy in Renal Transplant Recipients

PURPOSE

Our aim was to correlate the radiologic characteristics of cyclosporine-induced benign breast diseases with clinical and pathologic findings.

MATERIALS AND METHODS

The clinical, mammographic, and ultrasonographic records of 33 female renal transplant recipients who received cyclosporine were retrospectively reviewed. Eleven patients had 46 breast masses on ultrasonography. We performed core needle biopsies on 20 masses and reviewed the pathologic findings.

RESULTS

Among 33 female renal transplant recipients, 11 (33%) had 46 benign breast lesions detected on ultrasonography. We performed core needle biopsies on 20 of the 46 masses. On pathologic examination, 12 were fibroadenomas, 6 showed fibrocystic changes, and 2 revealed dense fibrosis. Regardless of the final pathologic diagnosis, more than half of the lesions revealed severe lymphatic and venular swellings. Among 11 patients with breast lesions on ultrasonography, 10/11 (91%) showed multiplicity, and 7/11 (64%) bilaterality. Mammographically, patients with breast lesions revealed heterogeneous or extremely dense breast patterns, and 8 of 11 patients, circumscribed masses. Twenty-two patients without breast lesions showed scattered fibroglandular densities (n = 7), or heterogeneously dense (n = 11) or extremely dense (n = 4) breast patterns, and 3 of 22 patients showed vague or asymmetric densities that needed further evaluation.

CONCLUSION

The development of new breast lesions in patients after renal transplantation should suggest a diagnosis of cyclosporine-induced benign breast disease including fibroadenoma, fibrocystic changes, and dense fibrosis.

Bilateral ocular osseous choristomas

Choristoma is a benign tumour defined as normal tissue in an ectopic location. Osseous choristoma, one subtype of this entity, occurring within the orbit has rarely been reported in the world literature. We report a 6-year-old girl with bilateral ocular osseous choristomas who presented with palpable nodules protruding from both upper lids. The radiological and clinical findings are described and previous reports are reviewed.

The relationship between serum resistin, leptin, adiponectin, ghrelin levels and bone mineral density in middle-aged men

OBJECTIVE

Body weight is a significant predictor of bone mass. Hormonal factors such as sex hormones, insulin, leptin and adiponectin are thought to play a role in the mechanisms controlling the association of body weight and fat mass with bone mass. However, contradictory results have been reported for the association between serum adipocytokines and bone mineral density (BMD). We therefore examined whether the serum adipocytokine and ghrelin levels, markers of fat metabolism, are associated with BMD in male adults.

PATIENTS AND MEASUREMENTS

For 80 male adults (average age 54.5 +/- 6.4 years; average body mass index (BMI) 24.4 +/- 2.5 kg/m2), the correlations between serum resistin, leptin, adiponectin and ghrelin levels with BMD were investigated.

RESULTS

Among the adipocytokines, serum resistin levels were negatively correlated with lumbar spine BMD (r = -0.237, P = 0.05). After adjustment was made for age and BMI, log-transformed serum leptin showed a significant negative correlation with lumbar spine BMD, which was not seen on bivariate analysis (r = -0.237, P = 0.039). Femoral neck BMD was marginally associated only with serum adiponectin levels (r = -0.226, P = 0.062). In multiple regression analyses, among the adipokines, only resistin was a significant determinant of lumbar spine BMD, although the variance was small (R2 = 0.256). Serum ghrelin levels were not correlated with the BMD of either body site.

CONCLUSIONS

Serum resistin level showed a significant negative correlation with lumbar spine BMD, although the variance was small. Further studies are needed to elucidate the role of adipocytokines in bone metabolism.