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.

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.

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.

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.

An analysis of radiological research publications in high impact general medical journals between 1996 and 2010.

OBJECTIVE: To evaluate scientific papers published by radiologists in high impact general medical journals between 1996 and 2010. METHODS: A MEDLINE search was performed in five high impact general medical journals (AIM, BMJ, JAMA, Lancet, and NEJM) for all articles of which a radiologist was the first author between 1996 and 2010. The following information was abstracted from the original articles: radiological subspecialty, imaging technique used, type of research, sample size, study design, statistical analysis, study outcome, declared funding, number of authors, collaboration, and country of the first author. RESULTS: Of 216 (0.19%) articles were published by radiologists in five general medical journals between 1996 and 2010, 83 were original articles. Fifteen (18.1%) original articles were concerned with the field of vascular/interventional radiology, 24 (28.9%) used combined imaging techniques, 76 (91.6%) were clinical research, 63 (75.9%) had a sample size of >50, 65 (78.3%) were prospective, 78 (94.0%) performed statistical analysis, 83 (100%) showed positive study outcomes, 57 (68.7%) were funded, 49 (59.0%) had from four to seven authors, and 79 (95.2%) were collaborative studies. CONCLUSIONS: A very small number (0.19%) in five high impact general medical journals was published by radiologists between 1996 and 2010.

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.

Prognostic significance of computed tomography defined ascites in advanced gastric cancer.

PURPOSE: The aim of this study was to investigate the clinicopathologic features and prognosis in patients with computed tomography (CT) findings of ascites, with a focus on the correlation with peritoneal carcinomatosis. METHODS: This study included a total of 157 patients who underwent surgery for advanced gastric cancer from 2003 to 2008 at the Department of Surgery, Hallym University Kangdong Sacred Heart Hospital, Seoul, Korea, which were analyzed retrospectively. RESULTS: Fourteen patients (8.9%) presented ascites on their CT scan. Among them, 10 patients had peritoneal carcinomatosis, and showed significant difference with CT ascites positive group in the incidence of peritoneal carcinomatosis. The presence of CT ascites was significantly correlated with pathologic T stage, tumor size, histologic type, CT T and N stages, CT peritoneal nodularity and curability of surgery, statistically. The prognosis of CT ascites positive group was much poorer in the total advanced gastric cancer patients (P < 0.001), as well as in patients with pathologic T4 (P = 0.002). Also in patients without peritoneal carcinomatosis, CT ascites positive subgroup tended to have a worse prognosis than CT ascites negative subgroup (P = 0.086). Tumor size, CT T and N stages and the presence of CT peritoneal nodularity and ascites influenced the prognosis significantly; among which, if a tumor size larger than 5 cm, CT T4 stage and the presence of CT ascites were identified as independent prognostic factors. CONCLUSION: The presence of ascites was closely associated with peritoneal metastasis, and was the most significant independent prognostic factor in advanced gastric cancer in the present study.

Compressibility of thyroid masses: a sonographic sign differentiating benign from malignant lesions?

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

Central venous stenosis of left versus right arm: its prevalence and effects on image quality in CT of the neck.

OBJECTIVE: The purpose of this study was (1) to evaluate the prevalence of the left and right central venous stenosis by measuring the narrowest area and (2) to assess the effects of the central venous stenosis on perivenous artifacts and reflux of contrast material, in CT of the neck. MATERIALS AND METHODS: Images of a total of 443 CT of the neck with an injection of contrast material into the left (n = 249) or right (n = 194) arm were retrospectively reviewed. The maximum stenosis area in the central vein ipsilateral to the injection side was measured in each patient. We also graded the perivenous artifacts and reflux of contrast material with 4-point scale. These results were compared between patients with right arm injection and those with left arm injection. RESULTS: The maximum stenosis area in the left arm was significantly smaller than that in the right arm. The stenosis was most frequently identified at the medial clavicular region. The mean scores of the perivenous artifacts and the reflux of contrast material were significantly higher in patients with left arm injection than in those with right arm injection. The perivenous artifacts and reflux of contrast material were more prominent in patients with central venous stenosis (maximum stenosis area <50mm(2)) than those without stenosis. CONCLUSIONS: The image degradation in CT of the neck, due to perivenous artifacts and venous reflux, can be reduced with the right arm injection of contrast material when compared with the left arm injection.

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.

Locally advanced thyroid cancer: can CT help in prediction of extrathyroidal invasion to adjacent structures?

OBJECTIVE: The purpose of this study was to determine the diagnostic accuracy of CT for detecting extrathyroidal invasion of thyroid cancer to adjacent structures. MATERIALS AND METHODS: Eighty-four patients (19 men, 65 women; age range, 19-84 years; mean, 54.2 +/- 15.4 years) with 86 malignant tumors of the thyroid with extracapsular extension (37 T3, 49 T4) were retrospectively enrolled in this study. Two radiologists independently evaluated the CT findings of invasion of thyroid cancer into the trachea, esophagus, common carotid artery, internal jugular vein, and recurrent laryngeal nerve. These results were compared with the surgical and histopathologic findings. RESULTS: The mean sensitivity, specificity, and accuracy of CT were as follows: 59.1%, 91.4%, and 83.2% for tracheal invasion; 28.6%, 96.2%, and 90.7% for esophageal invasion; 75.0%, 99.4%, and 98.8% for invasion of the common carotid artery; 33.3%, 98.8%, and 97.1% for invasion of the internal jugular vein; and 78.2%, 89.8%, and 85.5% for invasion to the recurrent laryngeal nerve. Interobserver agreement was moderate to good in the five categories of extrathyroidal invasion with a mean kappa value of 0.65 (range, 0.49-0.77). CONCLUSION: Although the effectiveness is limited by low sensitivity, CT may be a valuable tool for evaluation of extrathyroidal invasion of thyroid cancer to adjacent structures.

"Taller-than-wide sign" of thyroid malignancy: comparison between ultrasound and CT.

OBJECTIVE: The objective of our study was to investigate the mechanism of the "taller-than-wide sign"--that is, an anteroposterior dimension-to-transverse dimension ratio of >or= 1 on ultrasound. MATERIALS AND METHODS: Ultrasound and CT images of 90 pathologically proven thyroid masses (57 malignant and 33 benign) smaller than 2 cm in 77 patients (mean age, 45 years) were retrospectively reviewed. Two readers assessed the anteroposterior and transverse dimensions of the mass, anteroposterior-transverse ratio of the mass, anteroposterior dimension of the ipsilateral thyroid lobe, and the position of the common carotid artery (CCA) relative to the thyroid lobe. In addition, the difference in the anteroposterior-transverse ratio of the mass between ultrasound and CT was correlated with the ultrasound characteristics of the thyroid mass (i.e., maximal diameter, location, location within lobe, and composition), histopathologic results, and ultrasound operator. RESULTS: The mean (+/- SD) anteroposterior-transverse ratio of the thyroid masses on ultrasound was significantly lower than that on CT (0.97 +/- 0.34 vs 1.07 +/- 0.28, respectively; p < 0.001), and the differences were significantly greater in benign masses than malignant masses, in masses located at the anterior or mid third of the lobe than those located at the posterior third, and in cystic masses than mixed or solid masses. There were statistically significant differences between the two techniques with regard to the anteroposterior dimension of the ipsilateral thyroid lobe and the position of the CCA, suggesting the effect of probe compression. CONCLUSION: The mechanism of the taller-than-wide sign is no or minimal compressibility of a thyroid mass by the ultrasound probe, which occurs more frequently in malignant masses than in benign masses.

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.

Combination of magnetic resonance cholangiopancreatography and computed tomography for preoperative diagnosis of the Mirizzi syndrome.

OBJECTIVE: To determine the diagnostic accuracy of combined magnetic resonance cholangiopancreatography (MRCP) and computed tomography (CT) for preoperative diagnosis of Mirizzi syndrome. MATERIALS AND METHODS: Fifty-two patients with surgically proven Mirizzi syndrome (n = 13) and cholecystitis without evidence for Mirizzi syndrome (n = 39) underwent both MRCP using single-shot turbo spin echo and 3-dimensional turbo spin echo sequences and CT. Two blinded observers independently and retrospectively reviewed the combination of MRCP and CT images and CT images alone. Diagnostic accuracy for a combined protocol and CT was evaluated. RESULTS: The overall sensitivity, specificity, positive and negative predictive values, and accuracy of the combination of MRCP and CT were 96.0%, 93.5%, 83.5%, 98.5%, and 94.0%, respectively. Corresponding values of CT were 42.0%, 98.5%, 93.0%, 83.5%, and 85.0%, respectively. The sensitivity, negative predictive value, and accuracy of combined protocol were significantly higher than those of CT alone (P = 0.000, 0.001, and 0.042, respectively). Interobserver agreement was better for combined images (kappa = 0.906) than for CT images alone (kappa = 0.812). CONCLUSIONS: A combination of MRCP and CT is useful for preoperative diagnosis of Mirizzi syndrome.

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.

The prevalence and significance of incidental thyroid nodules identified on computed tomography.

PURPOSE: The purpose of this study was to assess the prevalence of incidental thyroid nodules (ITN) found on computed tomography (CT) of the neck and to determine whether CT characteristics could distinguish malignant from benign thyroid lesions. MATERIALS AND METHODS: We retrospectively reviewed CT scans in 734 patients without known thyroid disease (384 men and 350 women; mean age, 49.8 +/- 13.7 years). The CT findings of ITN such as size, shape (anteroposterior-transverse diameter ratio [AP/T ratio]), margin, peripheral enhancing rim, intralesional calcification, and attenuation characteristics were analyzed and correlated with ultrasonographic (US) findings. RESULTS: One hundred sixty ITNs were noted in 123 (16.8%) patients. Of 120 ITNs whose histological diagnoses were available, 15 (12.5%) were malignant. Malignant nodules more frequently showed nodular or rim calcifications (46.7% vs 13.3%; P < 0.0005), AP/T ratio of greater than 1.0 (33.3% vs 9.5%; P < 0.05), and mean attenuation value on contrast-enhanced scan of greater than 130 Hounsfield units (86.7% vs 49.5%; P < 0.05) than benign nodules. CONCLUSIONS: We found at least a 9.4% (15/160) prevalence of malignancy among ITN detected on CT. The further evaluation with US or biopsy should be performed, if an ITN shows CT features suggesting malignancy (calcification; AP/T ratio, >1.0; or mean attenuation value, >130 HU).

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 (< or = 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.

Computer-aided diagnosis for the differentiation of malignant from benign thyroid nodules on ultrasonography.

RATIONALE AND OBJECTIVES: We sought to evaluate the diagnostic performance of an artificial neural network (ANN) and binary logistic regression (BLR) in differentiating malignant from benign thyroid nodules on ultrasonography. MATERIALS AND METHODS: Two experienced radiologists, who were unaware of the histopathological diagnosis, analyzed ultrasonographic (US) features of 109 pathologically proven thyroid lesions (49 malignant and 60 benign) in 96 patients. Each radiologist was asked to evaluate US findings and categorize nodules into one of the two groups (malignant vs. benign) in each case. The following 8 US parameters were assessed for each nodule: size, shape, margin, echogenicity, cystic change, microcalcification, macrocalcification, and halo sign. Statistically significant US findings were obtained with backward stepwise logistic regression and were used for training and testing of the ANN and the BLR. The performance of the ANN and BLR was compared to that of the radiologists using receiver-operating characteristic (ROC) analysis. RESULTS: Statistically significant US findings were size, margin, echogenicity, cystic change, and macrocalcification of the nodules. The area under the ROC curve (Az) values of ANN and BLR were 0.9492 +/- 0.0195 and 0.9046 +/- 0.0289, respectively. The Az value was 0.8300 +/- 0.0359 for reader 1 and 0.7600 +/- 0.0409 for reader 2. The Az values for ANN and BLR were significantly higher than those for both radiologists (all p < .05). CONCLUSION: The performance of the ANN and the BLR was better than that of the radiologists in the distinction of benign and malignant thyroid nodules.