Publications by authors named "Ji Ye Lee"

40 Publications

Contrast-enhanced MRI T1 Mapping for Quantitative Evaluation of Putative Dynamic Glymphatic Activity in the Human Brain in Sleep-Wake States.

Radiology 2021 Jun 22:203784. Epub 2021 Jun 22.

From the Departments of Radiology (S.L., R.E.Y., S.H.C., J.Y.L., I.H., K.M.K., T.J.Y., J.H.K., C.H.S.) and Clinical Pharmacology and Therapeutics (K.Y.H.), Seoul National University Hospital, Seoul National University College of Medicine, 101 Daehangno, Jongno-gu, Seoul 03080, Republic of Korea; Center for Nanoparticle Research, Institute for Basic Science, Seoul, Republic of Korea (S.H.C.); School of Chemical and Biological Engineering (S.H.C.) and Department of Electrical and Computer Engineering (S.J., J.L.), Seoul National University, Seoul, Republic of Korea; and Department of Biomedical Engineering, Hankuk University of Foreign Studies, Yongin-si, Republic of Korea (S.H.O.).

Background Evaluation of the glymphatic system with intrathecal contrast material injection has limited clinical use. Purpose To investigate the feasibility of using serial intravenous contrast-enhanced T1 mapping in the quantitative evaluation of putative dynamic glymphatic activity in various brain regions and to demonstrate the effect of sleep on glymphatic activity in humans. Materials and Methods In this prospective study from May 2019 to February 2020, 25 healthy participants (mean age, 25 years ± 2 [standard deviation]; 15 men) underwent two cycles of MRI (day and night cycles). For each cycle, T1 maps were acquired at baseline and 0.5, 1, 1.5, 2, and 12 hours after intravenous contrast material injection. For the night cycle, participants had a normal night of sleep between 2 and 12 hours. The time () to reach the minimum T1 value (T1), the absolute difference between baseline T1 and T1 (peak ΔT1), and the slope between two measurements at 2 and 12 hours (slope) were determined from T1 value-time curves in cerebral gray matter (GM), cerebral white matter (WM), cerebellar GM, cerebellar WM, and putamen. Mixed-model analysis of variance (ANOVA), Friedman test, and repeated-measures ANOVA were used to assess the effect of sleep on slope and to compare and peak ΔT1 among different regions. Results The slope increased from the day to night cycles in cerebral GM, cerebellar GM, and putamen (geometric mean ratio [night/day] = 1.4 [95% CI: 1.2, 1.7], 1.3 [95% CI: 1.1, 1.4], and 2.4 [95% CI: 1.6, 3.6], respectively; = .001, < .001, and < .001, respectively). Median values were 0.5 hour in cerebral and cerebellar GM and putamen for both cycles. Cerebellar GM had the highest mean peak ΔT1, followed by cerebral GM and putamen in both day (159 msec ± 6, 99 msec ± 4, and 62 msec ± 5, respectively) and night (152 msec ± 6, 104 msec ± 6, and 58 msec ± 4, respectively) cycles. Conclusion Clearance of a gadolinium-based contrast agent was greater after sleep compared with daytime wakefulness. These results suggest that sleep was associated with greater glymphatic clearance compared with wakefulness. © RSNA, 2021 . See also the editorial by Anzai and Minoshima in this issue.
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http://dx.doi.org/10.1148/radiol.2021203784DOI Listing
June 2021

Diagnostic Performance of the Modified Korean Thyroid Imaging Reporting and Data System for Thyroid Malignancy: A Multicenter Validation Study.

Korean J Radiol 2021 Jun 1. Epub 2021 Jun 1.

Department of Radiology and Research Institute of Radiology, Asian Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Objective: To evaluate the diagnostic performance of the modified Korean Thyroid Imaging Reporting and Data System (K-TIRADS), and compare it with the 2016 version of K-TIRADS using the Thyroid Imaging Network of Korea.

Materials And Methods: Between June and September 2015, 5708 thyroid nodules (≥ 1.0 cm) from 5081 consecutive patients who had undergone thyroid ultrasonography at 26 institutions were retrospectively evaluated. We used a biopsy size threshold of 2 cm for K-TIRADS 3 and 1 cm for K-TIRADS 4 (modified K-TIRADS 1) or 1.5 cm for K-TIRADS 4 (modified K-TIRADS 3). The modified K-TIRADS 2 subcategorized the K-TIRADS 4 into 4A and 4B, and the cutoff sizes for the biopsies were defined as 1 cm for K-TIRADS 4B and 1.5 cm for K-TIRADS 4A. The diagnostic performance and the rate of unnecessary biopsies of the modified K-TIRADS for detecting malignancy were compared with those of the 2016 K-TIRAD, which were stratified by nodule size (with a threshold of 2 cm).

Results: A total of 1111 malignant nodules and 4597 benign nodules were included. The sensitivity, specificity, and unnecessary biopsy rate of the benign nodules were 94.9, 24.4, and 75.6 for the 2016 K-TIRADS; 91.0%, 39.7%, and 48.6% for the modified K-TIRADS 1; 84.9%, 45.9%, and 43.5% for the modified K-TIRADS 2; and 76.1%, 50.2%, and 40.1% for the modified K-TIRADS 3. For small nodules (1-2 cm), the diagnostic sensitivity of the modified K-TIRADS decreased by 5.2-25.6% and the rate of unnecessary biopsies reduced by 19.2-32.8% compared with those of the 2016 K-TIRADS ( < 0.001). For large nodules (> 2 cm), the modified K-TIRADSs maintained a very high sensitivity for detecting malignancy (98%).

Conclusion: The modified K-TIRADSs significantly reduced the rate of unnecessary biopsies for small (1-2 cm) nodules while maintaining a very high sensitivity for malignancy for large (> 2 cm) nodules.
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http://dx.doi.org/10.3348/kjr.2021.0230DOI Listing
June 2021

Prediction of brain age from routine T2-weighted spin-echo brain magnetic resonance images with a deep convolutional neural network.

Neurobiol Aging 2021 Apr 28;105:78-85. Epub 2021 Apr 28.

Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea. Electronic address:

Our study investigated the feasibility and clinical relevance of brain age prediction using axial T2-weighted images (T2-WIs) with a deep convolutional neural network (CNN) algorithm. The CNN model was trained by 1,530 scans in our institution. The performance was evaluated by the mean absolute error (MAE) between the predicted brain age and the chronological age based on an internal test set (n=270) and an external test set (n=560). The ensemble CNN model showed an MAE of 4.22 years in the internal test set and 9.96 years in the external test set. Participants with grade 2-3 white matter hyperintensity (WMH) showed a higher corrected predicted age difference (PAD) than grade 0 WMH (posthoc p<0.001). Participants diagnosed with diabetes mellitus also had a higher corrected PAD than those without diabetes (adjusted p=0.048), although it showed no significant differences according to the diagnosis of hypertension or dyslipidemia. We suggest that routine clinical T2-WIs are feasible to predict brain age, and it might be clinically relevant according to the WMH grade and the presence of diabetes mellitus.
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http://dx.doi.org/10.1016/j.neurobiolaging.2021.04.015DOI Listing
April 2021

2020 Imaging Guidelines for Thyroid Nodules and Differentiated Thyroid Cancer: Korean Society of Thyroid Radiology.

Korean J Radiol 2021 05 9;22(5):840-860. Epub 2021 Feb 9.

Department of Radiology, Gangneung Asan Hospital, Ulsan University College of Medicine, Gangneung, Korea.

Imaging plays a key role in the diagnosis and characterization of thyroid diseases, and the information provided by imaging studies is essential for management planning. A referral guideline for imaging studies may help physicians make reasonable decisions and minimize the number of unnecessary examinations. The Korean Society of Thyroid Radiology (KSThR) developed imaging guidelines for thyroid nodules and differentiated thyroid cancer using an adaptation process through a collaboration between the National Evidence-based Healthcare Collaborating Agency and the working group of KSThR, which is composed of radiologists specializing in thyroid imaging. When evidence is either insufficient or equivocal, expert opinion may supplement the available evidence for recommending imaging. Therefore, we suggest rating the appropriateness of imaging for specific clinical situations in this guideline.
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http://dx.doi.org/10.3348/kjr.2020.0578DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8076832PMC
May 2021

Effect of Initial Treatment Choice on 2-year Quality of Life in Patients with Low-risk Papillary Thyroid Microcarcinoma.

J Clin Endocrinol Metab 2021 Mar;106(3):724-735

Department of Internal Medicine, Seoul National University Hospital and College of Medicine, Seoul, Republic of Korea.

Context: The long-term quality of life (QoL) in patients with low-risk papillary thyroid microcarcinoma (PTMC) underwent active surveillance (AS) and immediate surgery is unclear.

Objective: The aim of this study was to investigate the effect of initial treatment choice on 2-year QoL in patients with low-risk PTMC.

Design, Setting, And Participants: We analyzed 2652 QoL surveys from 1055 subjects enrolled in ongoing multicenter prospective cohort study on active surveillance of PTMC, in which the median follow-up duration was 24.4 months.

Major Outcome Measure: We evaluated QoL of patients with low-risk PTMC according to their treatment modality using generalized estimating equation.

Results: Six hundred and seventy-four subjects (male = 161; mean age = 48.8 ± 11.9 years) with low-risk PTMC chose AS while 381 subjects (male = 75; mean age = 45.7 ± 10.4 years) chose immediate surgery, including lobectomy/isthmusectomy (L/I) and total thyroidectomy (TT). Among the 817 subjects who completed baseline QoL surveys, 2-year QoL was good in order of AS (n = 500), L/I (n = 238), and TT (n = 79) groups after adjustment for age, sex, baseline tumor size, and baseline QoL scores. Among the 101 subjects who changed their treatment from AS to surgery during the follow-up period, 35 subjects who changed treatment due to disease progression had better QoL than 66 subjects who had no disease progression.

Conclusions: This study identified QoL as a major issue in choosing an initial treatment of low-risk PTMC and highlighted the possibility of using AS as the primary treatment.
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http://dx.doi.org/10.1210/clinem/dgaa889DOI Listing
March 2021

The Value of Microvascular Imaging for Triaging Indeterminate Cervical Lymph Nodes in Patients with Papillary Thyroid Carcinoma.

Cancers (Basel) 2020 Oct 1;12(10). Epub 2020 Oct 1.

Department of Radiology, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon 14584, Korea.

Assessment of lymph node (LN) status in patients with papillary thyroid carcinoma (PTC) is often troublesome because of cervical LNs with indeterminate US (ultrasound) features. We aimed to explore whether Superb Microvascular Imaging (SMI) could be helpful for distinguishing metastasis from indeterminate LNs when combined with power Doppler US (PDUS). From 353 consecutive patients with PTC, LNs characterized as indeterminate by PDUS were evaluated by SMI to distinguish them from metastasis. Indeterminate LNs were reclassified according to the SMI, the malignancy risk of each category was assessed, and the diagnostic performance of suspicious findings on SMI was calculated. The incidence of US-indeterminate LNs was 26.9%. Eighty PDUS-indeterminate LNs (39 proven as benign, 41 proven as malignant) were reclassified into probably benign ( = 26), indeterminate ( = 20), and suspicious ( = 34) categories according to SMI, with malignancy risks of 19.2%, 20.0%, and 94.1%, respectively. After combining SMI with PDUS, 80.8% (21/26) of probably benign LNs and 94.1% (32/34) of suspicious LNs could be correctly diagnosed as benign and metastatic, respectively. The diagnostic sensitivity, specificity, and accuracy of categorizing LNs as suspicious based on SMI were 78.1%, 94.9%, and 86.3%, respectively. In conclusion, the combination of SMI with PDUS was helpful for the accurate stratification of indeterminate LNs based on US in patients with PTC.
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http://dx.doi.org/10.3390/cancers12102839DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7601686PMC
October 2020

Diagnostic Accuracy and Confidence of [18F] FDG PET/MRI in comparison with PET or MRI alone in Head and Neck Cancer.

Sci Rep 2020 06 11;10(1):9490. Epub 2020 Jun 11.

Department of Radiology, Seoul National University Hospital, 101, Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.

The usefulness of PET/MRI in head and neck malignancy has not been fully elucidated. The purpose of our study was to evaluate the diagnostic accuracy and confidence of PET/MRI in comparison with PET or MRI alone. This study included 73 consecutive patients who underwent [18F] FDG PET/MRI in head and neck under the suspicion of malignancy. A neuroradiologist and a nuclear medicine specialist reviewed MRI and PET images, respectively and independently, followed by a consensus review of PET/MRI one month later. For 134 lesions, accuracy and confidence were compared among PET, MRI, and PET/MRI. For lesion base, PET/MRI had a sensitivity of 85.7%, a specificity of 89.1%, a PPV of 89.6%, a negative predictive value of 85.1%, and an accuracy of 87.3%. AUCs of PET/MRI per lesion (0.926) and per patient (0.934) for diagnosing malignancy were higher than PET (0.847 and 0.747, respectively) or MRI (0.836 and 0.798, respectively) alone (P < 0.05). More than 80% of the cases (111/134) showed diagnostic concordance between PET and MRI. PPV of PET/MRI was higher in malignant concordant cases (93.2%, 55/59) than in discordant cases (62.5%, 5/8) (p = 0.040). Confident scoring rate in malignant concordant cases was higher on PET/MRI (96.6%, 57/59) than on MRI (76.3%, 45/59) (p = 0.003). In conclusion, compared with PET or MRI alone, PET/MRI presents better diagnostic performance in accuracy and confidence for diagnosis of malignancy. PET/MRI is useful in patients with head and neck cancer.
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http://dx.doi.org/10.1038/s41598-020-66506-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7289810PMC
June 2020

Effect of Metal Capping on the Stability of Amorphous Si-Zn-Sn-O Thin Film Transistor by Suppressing Ambient Effect.

J Nanosci Nanotechnol 2020 Aug;20(8):5002-5005

Department of Semiconductor Engineering, Cheongju University, Cheongju, 28503, South Korea.

By adopting metal capping layer (MC layer), electrical properties, such as field effect mobility, on current, and subthreshold swing showed enhanced characteristics with 24.996 cm²/Vs, 2.1×10 and 0.34 V/decade, respectively. In addition, the stability of the negative bias thermal stress (NBTS) against the ambient environment has been shown to be enhanced by the MC layer which acts like passivation layer. Without additional passivation layer, MC layer alone sufficiently inhibited the ambient effect to show low threshold voltage shift of 0.21 V compared with 0.89 V of conventional TFT. MC layer structure, enhancing the electrical characteristic and stability, had the advantages of a process that was much simpler than conventional process for high performance and stability.
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http://dx.doi.org/10.1166/jnn.2020.17836DOI Listing
August 2020

Investigation on energy bandgap states of amorphous SiZnSnO thin films.

Sci Rep 2019 Dec 17;9(1):19246. Epub 2019 Dec 17.

Department of Semiconductor Engineering, Cheongju University, Cheongju, 28503, South Korea.

The variation in energy bandgaps of amorphous oxide semiconducting SiZnSnO (a-SZTO) has been investigated by controlling the oxygen partial pressure (O). The systematic change in O during deposition has been used to control the electrical characteristics and energy bandgap of a-SZTO. As O increased, the electrical properties degraded, while the energy bandgap increased systematically. This is mainly due to the change in the oxygen vacancy inside the a-SZTO thin film by controlling O. Changes in oxygen vacancies have been observed by using X-ray photoelectron spectroscopy (XPS) and investigated by analyzing the variation in density of states (DOS) inside the energy bandgaps. In addition, energy bandgap parameters, such as valence band level, Fermi level, and energy bandgap, were extracted by using ultraviolet photoelectron spectroscopy, Kelvin probe force microscopy, and high-resolution electron energy loss spectroscopy. As a result, it was confirmed that the difference between the conduction band minimum and the Fermi level in the energy bandgap increased systematically as O increases. This shows good agreement with the measured results of XPS and DOS analyses.
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http://dx.doi.org/10.1038/s41598-019-55807-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6917747PMC
December 2019

Ultrasound malignancy risk stratification of thyroid nodules based on the degree of hypoechogenicity and echotexture.

Eur Radiol 2020 Mar 15;30(3):1653-1663. Epub 2019 Nov 15.

Division of Endocrinology and Metabolism, Department of Internal Medicine, Gangneung Asan Hospital, College of Medicine, University of Ulsan, Gangneung, 25440, Republic of Korea.

Objectives: The ultrasound (US) lexicon of nodule echogenicity and echotexture is one of the major differences among various risk stratification systems of thyroid nodules. This study aimed to stratify the US malignancy risk of thyroid nodules based on their degree of hypoechogenicity and echotexture.

Material And Methods: This retrospective study included a total of 2255 consecutive thyroid nodules (≥ 1 cm) with final diagnoses (malignancy rate, 13%) from 2011 to 2016. Thyroid nodules were stratified according to the US degree of hypoechogenicity (mild, moderate, or marked hypoechogenicity) and echotexture (homogeneous vs. heterogeneous). The calculated malignancy risk was compared between each category.

Results: There was no significant difference of malignancy risk between the homogeneous markedly hypoechoic and moderately hypoechoic nodules (p ≥ .18). However, the malignancy risks of markedly and moderately hypoechoic nodules were significantly higher than those of mildly hypoechoic nodules (p < .001). Heterogeneous predominantly hypoechoic thyroid nodules showed a significantly higher malignancy risk than predominantly iso- or hyperechoic thyroid nodules (p < .001). There were no significant differences of malignancy risk between heterogeneous predominantly hypoechoic and homogeneous hypoechoic nodules according to the degree of hypoechogenicity (p ≥ .12) and between heterogeneous predominantly iso- or hyperechoic nodules and homogeneous iso- or hyperechoic thyroid nodules (p = .36).

Conclusions: The malignancy risk of nodule hypoechogenicity is stratified as mild vs. moderate to marked hypoechogenicity, and the malignancy risk of nodules with heterogeneous echotexture is stratified by the predominant echogenicity of the nodules.

Key Points: • Thyroid nodule echogenicity is categorized as marked, moderate, or mild hypoechogenicity and iso- or hyperechogenicity with the reference standard of adjacent thyroid tissue and anterior neck muscles. • The malignancy risk of thyroid nodule echogenicity is stratified as iso- or hyperechoic vs. mild vs. moderate or marked hypoechogenicity. • The malignancy risk of nodules with heterogeneous echotexture is stratified by the predominant echogenicity.
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http://dx.doi.org/10.1007/s00330-019-06527-8DOI Listing
March 2020

Diagnostic Performance of Ultrasound Patterns by K-TIRADS and 2015 ATA Guidelines in Risk Stratification of Thyroid Nodules and Follicular Lesions of Undetermined Significance.

AJR Am J Roentgenol 2019 08 30;213(2):444-450. Epub 2019 Apr 30.

1 Department of Radiology, Soonchunhyang University, Bucheon Hospital, 170 Jomaru-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-767, Republic of Korea.

The objective of our study was to assess the malignancy rates of thyroid nodules in the cytologically determined subclass of atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) and to assess the diagnostic performance of ultrasound (US) patterns defined by the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and the 2015 American Thyroid Association (ATA) guidelines for risk stratification of AUS/FLUS nodules. From January 2010 to December 2016, 1340 thyroid nodules were diagnosed as AUS/FLUS via fine-needle aspiration biopsy. Of these, 683 cytopathologically confirmed nodules were included in this study. Each nodule was assigned to a category and US pattern, as defined by the K-TIRADS and ATA guidelines. US patterns were compared between benign and malignant nodules, and malignancy rates were calculated according to the subclasses of AUS/FLUS nodules and the K-TIRADS and ATA guidelines. Predictors of malignancy were assessed using logistic regression analysis. The overall malignancy rate of AUS/FLUS nodules was 47.4% (324/683). There were significant differences in malignancy risk among the subclasses ( = 0.001). There were significant differences in malignancy rates according to US patterns, K-TIRADS categories, and ATA categories ( < 0.001). The malignancy rates in the K-TIRADS categories of benign, low, intermediate, and high suspicion were 0%, 1.99%, 34.66%, and 89.00%, respectively ( < 0.001). The malignancy rates in the ATA categories of benign, very low, low, intermediate, and high suspicion were 0%, 0%, 3.33%, 33.54%, and 87.67% ( < 0.001). AUS/FLUS nodules with a final diagnosis of malignancy had significantly higher rates of suspicious US features and different K-TIRADS and ATA categories than benign nodules. US categories by K-TIRADS and ATA guidelines can be useful in predicting malignancy and risk stratification, and management planning can be adjusted according to US pattern.
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http://dx.doi.org/10.2214/AJR.18.20961DOI Listing
August 2019

Prognostic value of acoustic structure quantification in patients with Hashimoto's thyroiditis.

Eur Radiol 2019 Nov 15;29(11):5971-5980. Epub 2019 Apr 15.

Division of Endocrinology and Metabolism, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, South Korea.

Objectives: Assessment of thyroid parenchymal echogenicity on ultrasonography is a predictor of future thyroid dysfunction. Our objective was to determine the prognostic value of acoustic structure quantification (ASQ) to predict the outcome of patients with Hashimoto's thyroiditis (HT).

Materials And Methods: We prospectively evaluated 90 patients with HT using ASQ from May to December 2013. Surveillance for the development of overt hypothyroidism was conducted over a median period of 40 months (3-55). ASQ were dichotomized based on optimal cutoff values obtained from ROC curve analysis. The probability of developing overt hypothyroidism was compared between the dichotomized subgroups using Kaplan-Meier analysis and log-rank tests. Multivariate Cox regression analysis was performed to determine significant prognostic factors.

Results: The cumulative rate of overt hypothyroidism was 67.7%. The median interval to overt hypothyroidism was 27.9 months (95% confidence interval, 12.0-38.0 months). There was no significant difference in the risk of overt hypothyroidism using qualitative echogenicity between groups (p = 0.669) according to Kaplan-Meier analysis. However, the ASQ average (p < 0.001), standard deviation (p = 0.015), and focal disturbance ratio (p < 0.001) were significantly associated with an increased risk of overt hypothyroidism. Multivariate Cox regression analysis revealed that a higher ASQ average (hazard ratio, 1.03; p = 0.03) and higher thyroid-stimulating hormone level (hazard ratio, 1.02; p = 0.02) were independent predictors of overt hypothyroidism.

Conclusions: ASQ has potential as a prognostic biomarker for predicting the risk of overt hypothyroidism in patients with HT.

Key Points: • ASQ provides quantitative prognostic information of thyroid parenchymal echogenicity. • ASQ parameters improved the stratification of patients who are prone to develop overt hypothyroidism in HT. • ASQ can serve as prognostic biomarker in HT.
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http://dx.doi.org/10.1007/s00330-019-06174-zDOI Listing
November 2019

The association between thyroid echogenicity and thyroid function in pediatric and adolescent Hashimoto's thyroiditis.

Medicine (Baltimore) 2019 Apr;98(14):e15055

Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon.

In this study, we evaluated the association between thyroid echogenicity on ultrasonography (US) and thyroid function in pediatric and adolescent Hashimoto's thyroiditis (HT) patients.In 86 pediatric and adolescent HT patients, the association between echogenicity and thyroid function and microsomal autoantibody status was evaluated. Among patients with overt hypothyroidism, 89.2% (33/37) showed a US grade of 3 or 4. All of the patients at grade 4 presented with overt hypothyroidism. In contrast, 97.8% (44/49) of the patients with subclinical hypothyroidism or euthyroidism showed grades 1 or 2. Patients with increased thyroid-stimulating hormone titer also tended to have increased US grades (P < .001). In contrast, free thyroxine levels were significantly decreased with increasing US grade (P < .001).In conclusion, patients with higher US grades had decreased thyroid function (P < .001).
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http://dx.doi.org/10.1097/MD.0000000000015055DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6455779PMC
April 2019

Differentiation Between Malignant and Benign Lymph Nodes: Role of Superb Microvascular Imaging in the Evaluation of Cervical Lymph Nodes.

J Ultrasound Med 2019 Nov 3;38(11):3025-3036. Epub 2019 Apr 3.

Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.

Objectives: This study aimed to assess the value of Superb Microvascular Imaging (SMI; Canon Medical Systems, Otawara, Japan) for distinguishing between benign and malignant cervical lymph nodes (LNs) and to compare SMI with power Doppler ultrasound (PDUS).

Methods: Power Doppler ultrasound and SMI examinations were performed for patients' cervical LNs. The distribution of feeding vessels, number, and appearance of internal vessels were analyzed by 2 readers, and the results of PDUS and SMI were compared. Interobserver agreement was assessed. A subgroup analysis was performed to assess differences in vascular patterns between metastasis and tuberculous lymphadenitis and between Kikuchi disease and lymphoma. The diagnostic performance for distinguishing between benign and malignant LNs was calculated.

Results: In total, 147 patients with 147 cervical LNs (85 benign and 62 malignant) were assessed. Interobserver agreement was moderate to strong for SMI. There were significant differences in the vascular patterns between benign and malignant LNs on SMI (distribution, number, and appearance, all P < .001), but not on PDUS. In the subgroup analysis, SMI showed a significant difference in the vascular patterns observed between metastasis and tuberculous lymphadenitis (distribution, P = .012; number, P = .014; and appearance, P = .005). Superb Microvascular Imaging detected significantly greater numbers of vessels in lymphoma than in Kikuchi disease (P = .012). The sensitivity of SMI was significantly greater than that of PDUS in distinguishing malignant from benign LNs (86.9% versus 54.1%; P < .001).

Conclusions: Superb Microvascular Imaging yields more detailed information about nodal vessels than does PDUS by enabling visualization of small nodal vessels. Superb Microvascular Imaging is useful and feasible for differentiating between malignant and benign cervical LNs.
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http://dx.doi.org/10.1002/jum.15010DOI Listing
November 2019

Permeability measurement using dynamic susceptibility contrast magnetic resonance imaging enhances differential diagnosis of primary central nervous system lymphoma from glioblastoma.

Eur Radiol 2019 Oct 15;29(10):5539-5548. Epub 2019 Mar 15.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 43 Olympic-ro 88, Songpa-Gu, Seoul, 05505, Republic of Korea.

Objectives: To test if adding permeability measurement to perfusion obtained from dynamic susceptibility contrast MRI (DSC-MRI) improves diagnostic performance in the differentiation of primary central nervous system lymphoma (PCNSL) from glioblastoma.

Materials And Methods: DSC-MRI was acquired in 145 patients with pathologically proven glioblastoma (n = 89) or PCNSL (n = 56). The permeability metrics of contrast agent extraction fraction (E), apparent permeability (K), and leakage-corrected perfusion of normalized cerebral blood volume (nCBV) and cerebral blood flow (nCBF) were derived from a tissue residue function. For comparison purposes, the leakage-corrected normalized CBV (nCBV) and relative permeability constant (K) were also obtained using the established Weisskoff-Boxerman leakage correction method. The area under the receiver operating characteristics curve (AUC) and cross-validation were used to compare the diagnostic performance of the single DSC-MRI parameters with the performance obtained with the addition of permeability metrics.

Results: PCNSL demonstrated significantly higher permeability (E, p < .001) and lower perfusion (nCBV, nCBF, and nCBV, all p < .001) than glioblastoma. The combination of E and nCBV showed the highest performance (AUC, 0.96; 95% confidence interval, 0.92-0.99) for differentiating PCNSL from glioblastoma, which was a significant improvement over the single perfusion (nCBV: AUC, 0.84; nCBV: AUC, 0.84; nCBF: AUC, 0.82; all p < .001) or E (AUC, 0.80; p < .001) parameters.

Conclusions: Analysis of the combined permeability and perfusion metrics obtained from a single DSC-MRI acquisition improves the diagnostic value for differentiating PCNSL from glioblastoma in comparison with single-parameter nCBV analysis.

Key Points: • Permeability measurement can be calculated from DSC-MRI with a tissue residue function-based leakage correction. • Adding Eto CBV aids in the differentiation of PCNSL from glioblastoma. • CBV and Emeasurements from DSC-MRI were highly reproducible.
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http://dx.doi.org/10.1007/s00330-019-06097-9DOI Listing
October 2019

Feasibility of magnetic resonance imaging in the differential diagnosis of isolated acute audiovestibular loss.

J Vestib Res 2018 ;28(5-6):385-391

Department of Otorhinolaryngology - Head and Neck Surgery, Soonchunhyang University College of Medicine, Bucheon, Korea.

Background: Isolated acute audiovestibular loss is characterized by the sudden onset of unilateral hearing loss and prolonged vertigo.

Objective: The purpose of this study is aimed to identify the value of magnetic resonance imaging (MRI) for the evaluation of isolated acute audiovestibular loss.

Methods: We retrospectively enrolled 31 patients with isolated acute audiovestibular loss from March 2007 to December 2017. Specific medical records including initial and final pure tone audiometry (PTA), and canal paresis value were reviewed. Abbreviated MRI was performed in all patients.

Results: Fifteen patients showed increased signal of labyrinth on FLAIR images and eleven revealed negative findings on MRI. Two patients showed an infarction in the anterior inferior cerebellar artery (AICA) territory and three exhibited vestibular schwannoma in the internal auditory canal. There were no significant differences in initial, final PTA, and hearing recovery between negative and labyrinthine abnormality groups on MRI.

Conclusions: Our results show that isolated acute audiovestibular loss due to labyrinthitis is more common than other secondary causes including vestibular schwannoma or AICA infarction. However, MRI with a tailored, abbreviated protocol is strongly recommended in patients with isolated acute audiovestibular loss to identify the exact etiologies.
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http://dx.doi.org/10.3233/VES-190649DOI Listing
November 2019

Analysis of mutation in thyroid nodular hyperplasia and follicular neoplasm in a Korean population.

Endocrinol Diabetes Metab 2018 Oct 3;1(4):e00040. Epub 2018 Sep 3.

Department of Radiology Soonchunhyang University Bucheon Hospital Bucheon Korea.

Background: To investigate the difference in frequency of mutations between nodular hyperplasia (NH), follicular thyroid adenomas (FTAs) and follicular thyroid carcinomas (FTCs) in a Korean population.

Methods: mutations in 50 NH, 57 FTAs and 39 FTCs between January 2002 and May 2015 were analysed by pyrosequencing.

Results: Nine nodules of 50 NHs (18%), 18 nodules of 39 FTCs (46.2%) and 19 nodules of 57 FTAs (33.3%) harboured mutations. Three FTCs and three FTAs showed two point mutations simultaneously. codon 61 (n=6 of 9, 66.7%) and codon 61 (n=3 of 9, 33.3%) were found in NHs. codons 12-13, codon 61, codons 12-13 and codons 12-13 were not found in NHs. codon 61 (n=7 of 21, 33.3%), codons 12-13 (n=6 of 21, 28.6%), codon 61 (n=4 of 21, 19.0%), codon 61 (n=3 of 21, 14.3%) and codons 12-13 (n=1 of 21, 4.7%) were found in FTCs, and codon 61 (n=10 of 22, 45.5%), codons 12-13 (n=5 of 22, 22.7%), codon 61 (n=5 of 22, 22.7%), codon 61 (n=1 of 22, 4.5%) and codons 12-13 (n=1 of 22, 4.5%) were observed in FTAs.

Conclusions: The frequencies of RAS mutations among our Korean population were 18% in NHs, 46.2% in FTC and 33.3% in FTAs. N-RAS codon 61 was the most frequent mutation in NHs, FTCs and FTAs, and the frequency was not significantly different among the three groups. K-RAS codons 12-13 were the second most commonly involved site in FTCs and FTAs, whereas no mutation was detected at this site in NHs.
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http://dx.doi.org/10.1002/edm2.40DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6354824PMC
October 2018

Reliability of fast magnetic resonance imaging for acute ischemic stroke patients using a 1.5-T scanner.

Eur Radiol 2019 May 12;29(5):2641-2650. Epub 2018 Nov 12.

Department of Neurology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

Objectives: To determine whether fast scanned MRI using a 1.5-T scanner is a reliable method for the detection and characterization of acute ischemic stroke in comparison with conventional MRI.

Methods: From May 2015 to June 2016, 862 patients (FLAIR, n = 482; GRE, n = 380; MRA, n = 190) were prospectively enrolled in the study, with informed consent and under institutional review board approval. The patients underwent both fast (EPI-FLAIR, ETL-FLAIR, TR-FLAIR, EPI-GRE, parallel-GRE, fast CE-MRA) and conventional MRI (FLAIR, GRE, time-of-flight MRA, fast CE-MRA). Two neuroradiologists independently assessed agreements in acute and chronic ischemic hyperintensity, hyperintense vessels (FLAIR), microbleeds, susceptibility vessel signs, hemorrhagic transformation (GRE), stenosis (MRA), and image quality (all MRI), between fast and conventional MRI. Agreements between fast and conventional MRI were evaluated by generalized estimating equations. Z-scores were used for comparisons of the percentage agreement among fast FLAIR sequences and fast GRE sequences and between conventional and fast MRA.

Results: Agreements of more than 80% were achieved between fast and conventional MRI (ETL-FLAIR, 96%; TR-FLAIR, 97%; EPI-GRE, 96%; parallel-GRE, 98%; fast CE-MRA, 86%). ETL- and TR-FLAIR were significantly superior to EPI-FLAIR in the detection of acute ischemic hyperintensity and hyperintense vessels, while parallel-GRE was significantly superior to EPI-GRE in the detection of susceptibility vessel sign (p value < 0.05 for all). There were no significant differences in the other scores and image qualities (p value > 0.05).

Conclusions: Fast MRI at 1.5 T is a reliable method for the detection and characterization of acute ischemic stroke in comparison with conventional MRI.

Key Points: • Fast MRI at 1.5 T may achieve a high intermethod reliability in the detection and characterization of acute ischemic stroke with a reduction in scan time in comparison with conventional MRI.
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http://dx.doi.org/10.1007/s00330-018-5812-5DOI Listing
May 2019

Acute vertigo and sensorineural hearing loss from infarction of the vestibulocochlear nerve: A case report.

Medicine (Baltimore) 2018 Oct;97(41):e12777

Department of Radiology.

Rationale: Acute unilateral audiovestibulopathy is a common neurotological syndrome. Differential diagnoses of acute unilateral audiovestibulopathy include viral infection, vascular insults, and tumors. Regarding vascular causes, ischemic stroke in the anterior inferior cerebellar artery (AICA) territory is known to be the leading cause of acute audiovestibular loss. Previous reports of AICA infarction with audiovestibulopathy failed to demonstrate magnetic resonance imaging (MRI)-positive vestibulocochlear infarctions. Only 1 report demonstrated acute infarction involving the vestibulocochlear nerve on diffusion weighted imaging (DWI)-MRI.

Patient Concerns: A 67 year old man complained of sudden left hearing loss and vertigo. The patient showed left horizontal gaze-evoked nystagmus (GEN) and the head impulse test (HIT) was positive on the left side. Videonystagmography revealed spontaneous rebound nystagmus toward the right side; head-shaking nystagmus toward the right side. The patient presented with left caloric paresis (20.1%). Pure tone audiometry (PTA) revealed severe sensorineural hearing loss on the left side.

Diagnosis: MRI of temporal bone showed multifocal acute infarctions in the left inferior cerebellum. Moreover, images revealed tiny infarctions along the left vestibulocochlear nerve and the cochlea, implying acute vestibulocochlear nerve and labyrinthine infarction. There was no evidence of steno-occlusion of major cerebral vessels on MR angiography.

Interventions: Immediate stroke management was done.

Outcomes: Neurological symptoms gradually improved after 3 to 5 days.

Lessons: We present a case illustrating a rare but significant finding of vestibulocochlear nerve infarction revealed by DWI-MRI. Prompt imaging protocol enabled the detection of significant findings in this patient with acute unilateral audiovestibulopathy. Clinicians should be aware of the vestibulocochlear nerve and labyrinth on MRI in patients with cerebellar stroke.
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http://dx.doi.org/10.1097/MD.0000000000012777DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203587PMC
October 2018

Dehiscent high-riding jugular bulb presenting as conductive hearing loss: A case report.

Medicine (Baltimore) 2018 Jun;97(26):e11067

Department of Radiology Department of Otorhinolaryngology-Head and Neck Surgery, Soonchunhyang University Bucheon Hospital, Wonmi-gu, Bucheon, Korea.

Rationale: Jugular bulb anomalies are asymptomatic lesions commonly seen in routine practice. However, some patients with jugular bulb anomalies may present with symptoms such as tinnitus or conductive hearing loss (CHL).

Patient Concerns: A 9 year old boy complained right sided hearing disturbance without any vestibular symptoms. Pure tone audiometry (PTA) revealed a mild right sided conductive hearing loss. Otoscopy showed a red-purplish mass like lesion in his right middle ear cavity, which was regarded as hypervascular tumor.

Diagnosis: Based on otoscopic findings, preliminary differential diagnoses included jugular bulb anomaly, hemotympanum, cholesterol granuloma and paraganglioma.

Interventions: We performed contrast enhanced computed tomography of the temporal bone (TBCT).

Outcomes: CT scan showed and enhancing lesion which was bulging from his right jugular foramen to the middle ear with dehiscent jugular bulb. The lesion showed the same degree of contrast enhancement with the venous vasculature. This lesion contacted with the tympanic membrane, incudostapedial joint and round window, which might be attributable to interruption of sound transmission mechanics. Otherwise there was no evidence of mass or trauma related lesions in the temporal bone.

Lessons: Although most of jugular bulb anomalies are asymptomatic, patients may present with conductive hearing loss due to the interference of sound transmission mechanics.
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http://dx.doi.org/10.1097/MD.0000000000011067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039638PMC
June 2018

Intracranial hemorrhage in term neonates.

Childs Nerv Syst 2018 06 10;34(6):1135-1143. Epub 2018 Apr 10.

Department of Radiology, Soonchunhyang University Bucheon Hospital, 170 Jomaru-ro, Wonmi-gu, Bucheon, 420-767, Republic of Korea.

Background: Intracranial hemorrhage (ICH) is an uncommon but important cause of morbidity and mortality in term neonates; currently, ICH is more frequently diagnosed because of improved neuroimaging techniques.

Purpose: The study aims to evaluate the clinical characteristics and neuroimaging data (pattern, size, distribution) of neonatal ICH.

Methods: We reviewed MRI data from July 2004 to June 2015 for 42 term neonates with ICH who were less than 1 month old. We recorded clinical data and manifestations, mode of delivery, Apgar score at 1 and 5 min, associated hypoxic insult, birth trauma, neurological symptoms, EEG results, extent and site of hemorrhage, neurosurgical intervention, and developmental outcomes. The clinical outcome was determined for 27 neonates. Risk factors were assessed in relation to ICH.

Results: A total of 42 neonates who presented with ICH underwent MR imaging 2 to 22 days postnatally (mean age 9.3 days). The majority of clinical symptoms were present in patients within the first 24 h of life (n = 31), but symptoms appeared until day 10 postnatally (mean 4.9 days, n = 11). Seizure or seizure-like activity was the most common presenting symptom (17/42, 40.5%), with apnea seen in another seven infants (7/42, 16.7%). The majority of infants had a normal prenatal course. Two patients had antenatally detected hydrocephalus. Ten had infratentorial hemorrhage, and two had supratentorial hemorrhage. A total of 30 infants had a combination of infratentorial and supratentorial hemorrhage. Subdural hemorrhage (SDH) was the most common type of hemorrhage (40/42, 95.2%), followed by nine cases of parenchymal hemorrhage, seven of subarachnoid hemorrhage, three of germinal matrix hemorrhage (GMH), and one of epidural hemorrhage (EDH). A total of 16 infants had two or more types of hemorrhage. SDH was identified along the tentorium (n = 38) as well as over the cerebellar hemispheres (n = 39), along the interhemispheric fissure (n = 10), and over the occipital (n = 13) or parietooccipital (n = 11) lobes. Intraparenchymal hemorrhage involved either the frontal (n = 4), parietal (n = 3), or cerebellar (n = 2) lobes. Traumatic delivery was suspected in 20 patients (47.6%), and perinatal asphyxia was present in 21 patients (50.0%). A low Apgar score at 5 min and a history of perinatal asphyxia were the factors that most predicted poor clinical outcomes (n = 12/27). Logistic regression analysis revealed that a history of perinatal asphyxia resulted in poor outcomes. No patients died. One infant required burr hole drainage of a right parietal EDH, one infant needed a subcutaneous reservoir, and three infants required a ventriculoperitoneal shunt for obstructive hydrocephalus.

Conclusion: SDH was the most common type of ICH in term infants. Combined supratentorial and infratentorial hemorrhage was more common than isolated infratentorial hemorrhage in these infants. A total of 44.4% of patients had poor outcomes, with perinatal asphyxia the most common statistically significant cause.
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http://dx.doi.org/10.1007/s00381-018-3788-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5978839PMC
June 2018

Thyroid nodules and cancer in children and adolescents affected by Hashimoto's thyroiditis.

Br J Radiol 2018 Jul 9;91(1087):20180014. Epub 2018 Apr 9.

Department of Radiology, Soonchunhyang University Bucheon Hospital , Bucheon , Korea.

Objective: To investigate the rates of thyroid nodules and cancer in pediatric cases of Hashimoto's thyroiditis (HT) in Korea.

Methods: We retrospectively reviewed 89 pediatric and adolescent patients (age, 3-18.0 years) with HT who underwent thyroid ultrasonography (US) at our institution from February 2006 to July 2016. The diagnosis of HT was based on the presence of thyroid autoantibodies. The presence of any thyroid nodules with US and cytopathologic features was analyzed. The malignancy rate was also determined.

Results: Thyroid nodules were in 20 of the 89 patients (22.4%). Eight of these 20 patients (40%) had colloid cysts, two (10%) had nodular hyperplasia, one (5%) had follicular adenoma, and two (10%) had lymphocytic thyroiditis. Seven of the 89 patients (7.9%) were confirmed to have a malignancy, all of which were papillary thyroid carcinoma (PTC); of those, five patients had diffuse sclerosing variant PTC, and two had conventional PTC on pathology.

Conclusion: The prevalence of thyroid nodules in children and adolescents with HT was 22.4%. The malignancy rate of children with HT was 7.9%. The malignancy rate among thyroid nodules was 35%, which is higher than the 26% rate generally reported for children with nodules. Therefore, using thyroid US to survey known or suspected thyroid nodules might be helpful in children and adolescents with HT and may provide further useful diagnostic information. Advances in knowledge: Thyroid US could help to assess HT patients who have known or suspected thyroid nodules.
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http://dx.doi.org/10.1259/bjr.20180014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221765PMC
July 2018

Diagnosis of Cerebral Aneurysm Via Magnetic Resonance Angiography Screening: Emphasis on Legal Responsibility Increases False Positive Rate.

Neurointervention 2018 Mar 2;13(1):48-53. Epub 2018 Mar 2.

Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Purpose: False positive diagnoses of cerebral aneurysm via magnetic resonance angiography (MRA) screening may increase unnecessary cerebral catheter angiography. The purpose of this study was to investigate the effects of medical liability on medical decision-making during radiologic interpretation.

Materials And Methods: We included 56 consecutive patients who were referred with suspected aneurysm based on MRA or computed tomography angiography (CTA) and showed no aneurysm on subsequent digital subtraction angiography (DSA). MRA and CTA were reviewed twice by two neuroradiology fellows who were blind as to whether the suspected lesions were true aneurysms or not. The second review was repeated after proposing that their decision was subject to legal liability and they would be responsible for medico-legal problems related to their diagnoses. Diagnostic differences based on each review were analyzed, focusing on changes in false positive diagnosis rates.

Results: A total of 63 suspected aneurysmal lesions detected via MRA or CTA were found to be negative based on DSA. At first review, 32 lesions were diagnosed as true aneurysms by observer 1 and 27 by observer 2, corresponding to false positive rates of 51% and 43% respectively. At the second review, 39 lesions (62%) were diagnosed by observer 1, and 30 (48%) by observer 2. Thus, there was an overall increase in false positive aneurysm diagnosis of 11% for observer 1 and 5% for observer 2, after emphasizing their responsibilities in the context of medical litigation.

Conclusion: Concerns about medical liability could result in increased false positive diagnoses of cerebral aneurysms via MRA screening. Whether repeated follow-up of the suspected lesion or catheter angiographic confirmation is better with regard to long-term patient outcomes requires further study.
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http://dx.doi.org/10.5469/neuroint.2018.13.1.48DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5847890PMC
March 2018

Amide proton transfer imaging seems to provide higher diagnostic performance in post-treatment high-grade gliomas than methionine positron emission tomography.

Eur Radiol 2018 Aug 27;28(8):3285-3295. Epub 2018 Feb 27.

Department of Nuclear Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Objectives: To compare the diagnostic performance of amide proton transfer (APT) imaging and 11-C methionine positron emission tomography (MET-PET) for in vivo molecular imaging of protein metabolism in post-treatment gliomas.

Materials And Methods: This study included 43 patients (12 low and 31 high grade) with post-treatment gliomas who underwent both APT and MET-PET imaging within 3 weeks. APT-weighted voxel values and semi-quantitative tumour-to-normal ratios (TNR) were obtained from tumour portions. The voxel-wise relationships between TNR and APT were assessed. The diagnostic performance for recurrence of high-grade gliomas was calculated, using the area under the receiver operating characteristic curve (AUC) with maximum (TNR and APT) and 90% histogram values (TNR90 and APT90).

Results: A moderate positive correlation between TNR and APT was found in low-grade recurrences (r = 0.47, p < 0.001), but not in high-grade ones (r = -0.24, p < 0.001). For distinguishing recurrence in post-treatment high-grade gliomas, APT (AUC, 0.88) and APT90 (AUC, 0.78-0.83) had a similar to better diagnostic performance than TNR (AUC, 0.71, p = 0.08) or TNR90 (AUC, 0.53-0.59, p = 0.01-0.05).

Conclusions: In post-treatment high-grade gliomas, APT provides different regional information to MET-PET and provides higher diagnostic performance. This difference needs to be considered when using APT or MET-PET as a surrogate marker for tumour protein metabolism.

Key Points: • APT and TNR values in low-grade recurrence showed a moderate voxel-wise correlation. • APT and TNR demonstrated regional differences in post-treatment high-grade gliomas. • APT90 showed better diagnostic performance than TNR90 in high-grade recurrence.
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http://dx.doi.org/10.1007/s00330-018-5341-2DOI Listing
August 2018

MRI Findings of Adult-Onset Orbital Xanthogranulomatous Disease : A Case Report.

Clin Neuroradiol 2018 Dec 9;28(4):601-604. Epub 2018 Feb 9.

Department of Pathology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea (Republic of).

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http://dx.doi.org/10.1007/s00062-018-0673-5DOI Listing
December 2018

Normative Values for Tonsils in Pediatric Populations Based on Ultrasonography.

J Ultrasound Med 2018 Jul 23;37(7):1657-1663. Epub 2017 Dec 23.

Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.

Objectives: Pediatric tonsillar infections are common, particularly in adolescents. Ultrasonography (US) has high sensitivity and specificity for diagnosing peritonsillar abscesses and can diagnose tonsillitis by enlargement of the gland. In this study, we established normal tonsillar measurements and volumes according to age in pediatric populations.

Methods: Transcervical US of the peritonsillar region to measure tonsillar size and volume was performed in patients who had undergone neck US without throat symptoms from October 2016 to May 2017. Transverse and anteroposterior diameters, length, and volume were measured.

Results: In total, 161 patients (age range, 1 month-18 years) were enrolled in the study. The mean tonsillar volumes ± SD were 1.58 ± 1.26 (total), 0.30 ± 0.14 (<1 year), 1.27 ± 0.57 (1-<5 years), 2.06 ± 1.09 (5-<10 years), and 2.19 ± 1.48 (>10 years) cm . Mean measurements for the sums of both tonsils for the transverse diameter, anteroposterior diameter, and length were 1.98 ± 0.61, 2.17 ± 0.66, and 2.28 ± 0.69 cm, respectively. Tonsillar size and volume increased according to age. Simplified models for volume estimation showed that anteroposterior diameters had the highest coefficients of determination (R  = 0.71 and 0.74). Regression models for the tonsillar volume of 6 measurements in the multiple linear regression models showed an R of 0.89. Regression models for log(volume) showed an improved coefficient of determination (R  = 0.96).

Conclusions: These normal tonsillar sizes on transcervical ultrasound in pediatric patients can be used to diagnose tonsillar lesions.
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http://dx.doi.org/10.1002/jum.14513DOI Listing
July 2018

Joint approach based on clinical and imaging features to distinguish non-neoplastic from neoplastic pituitary stalk lesions.

PLoS One 2017 15;12(11):e0187989. Epub 2017 Nov 15.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.

Purpose: Distinguishing non-neoplastic pituitary stalk lesions (non-NPSLs) from neoplastic pituitary stalk lesions (NPSLs) is a major concern in guiding treatment for a thickened pituitary stalk. Our study aimed to aid provide preoperative diagnostic assistance by combining clinical and magnetic resonance imaging (MRI) findings to distinguish non-NPSLs from NPSLs.

Materials And Methods: We recruited 158 patients with thickened pituitary stalk lesions visible on MRI. Laboratory findings included hypopituitarism, diabetes insipidus (DI), and hyperprolactinemia. MR images were assessed for anterior-posterior thickness (mm), diffuse pituitary stalk thickening, cystic changes, a high T1 signal, and glandular or extrasellar involvement. A diagnostic model was developed using a recursive partitioning logistic regression analysis. The model was validated in an independent dataset comprising 63 patients, and its diagnostic performance was compared with that of the original radiological reports.

Results: A univariate analysis found significant associations of DI (P = 0.006), absence of extrasellar involvement (P = 0.002), and lower stalk thickness (P = 0.031) with non-NPSLs. A diagnostic model was created using the following parameters (in order of priority): 1) lack of extrasellar involvement, 2) stalk thickness < 5.3 mm, and 3) presence of DI. The diagnostic performance (area under the curve; AUC) of this model in the independent set was 0.813, representing a significant improvement over the original radiological reports (AUC: 0.713, P = 0.029).

Conclusion: The joint diagnostic approach based on clinical and imaging-based factors robustly distinguished non-NPSLs from NPSLs. This approach could guide treatment strategies and prevent unnecessary surgery in patients with non-NPSL.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0187989PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5687750PMC
December 2017

Visualization of Soft Tissue Venous Malformations of Head and Neck with 4D Flow Magnetic Resonance Imaging.

Neurointervention 2017 Sep 5;12(2):110-115. Epub 2017 Sep 5.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.

Evaluation of hemodynamics in venous malformation (VM) in the head and neck area is done by direct puncture venography before alcohol sclerotherapy, but it is difficult due to a variable degree of filling in from the artery and filling out into the draining vein. We present our preliminary experience of 4D MRI to evaluate VM hemodynamics. Four patients with venous malformation in the maxillofacial area underwent both 4D MRI and direct puncture venography before alcohol sclerotherapy. To find out appropriate velocity encoding (VENC) for VM, we applied 5-50 cm/sec VENC. Significant high-flow foci demonstrated by phase changes in magnitude images were compared with lesion types shown on a direct puncture venogram. Detection of flow in VM was possible in magnitude images or phase-difference images when VENC was set to less than 30 cm/sec. Appropriate VENC for VM was regarded as less than 5 cm/sec. High-flow areas in the dilated venous sac demonstrated focal spots or linear band-like areas on phase changes of 4D MRI. Appropriate VENC application was mandatory to detect flow in VM. Flow information on 4D MRI provided flow information in VM which was not detected on a direct puncture venogram in the compartmentalized lesion and thus can make alcohol sclerotherapy safer.
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http://dx.doi.org/10.5469/neuroint.2017.12.2.110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613042PMC
September 2017

Up to 52 administrations of macrocyclic ionic MR contrast agent are not associated with intracranial gadolinium deposition: Multifactorial analysis in 385 patients.

PLoS One 2017 31;12(8):e0183916. Epub 2017 Aug 31.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.

Purpose: To determine whether multiple repeated administrations of gadolinium-based macrocyclic ionic MR contrast agent (MICA) are associated with intracranial gadolinium deposition and identify the predisposing factors for deposition in various clinical situations.

Materials And Methods: In this institutional review board-approved retrospective study, 385 consecutive patients who underwent MICA-enhanced MR imaging were enrolled. The dentate nucleus-to-pons (DN/P) and globus pallidus-to-thalamus (GP/Th) signal intensity (SI) ratios on unenhanced T1-weighted images were recorded by 2 independent readers and averaged. The mean DN/P and GP/Th SI ratio difference between the last and the first examinations were tested using the one-sample t-test. Student's t-test and stepwise regression analysis were used to identify the predisposing factors for deposition based on the number of administrations, time interval, hepatic and renal function, magnetic field strength, and chemo- or radiation therapy.

Results: The mean DN/P SI ratio difference was not different from zero (P = .697), even in patients with ≥20 administrations (n = 33). Only patients with abnormal renal function showed an increase in the mean DN/P SI ratio difference (P = .019). The mean DN/P SI ratio difference was not associated with any predisposing factors. However, the mean GP/Th SI ratio difference showed decrease (P < .001), which was associated with age (P = .007), number of administrations (P = .01) and number of radiation therapy sessions (P = .022) on multivariate analysis.

Conclusion: Multiple repeated administrations of MICA were not associated with increased T1 signal intensity in deep brain nuclei suggestive of Gd deposition in patients with normal renal function.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0183916PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5578663PMC
October 2017

Thyroid disease in children and adolescents.

Ultrasonography 2017 Oct 28;36(4):289-291. Epub 2017 May 28.

Department of Radiology, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.

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http://dx.doi.org/10.14366/usg.17031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5621805PMC
October 2017
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