Publications by authors named "Sun-Won Park"

67 Publications

Differences in Brain Morphology between Hydrocephalus Ex Vacuo and Idiopathic Normal Pressure Hydrocephalus.

Psychiatry Investig 2021 Jul 16;18(7):628-635. Epub 2021 Jul 16.

Department of Neurosurgery, Seoul National University College of Medicine & SMG-SNU Boramae Medical Center, Seoul, Republic of Korea.

Objective: The distinction between idiopathic normal pressure hydrocephalus (iNPH) and hydrocephalus ex vacuo caused by encephalic volume loss remains to be established. This study aims to investigate radiological parameters as clinically useful tools to discriminate iNPH from hydrocephalus ex vacuo caused by Alzheimer's disease (AD).

Methods: A total of 54 patients with ventriculomegaly (iNPH, 25; hydrocephalus ex vacuo, 29) were recruited in this study. Consequently, nine radiological parameters were compared between iNPH and hydrocephalus ex vacuo using magnetic resonance imaging (MRI).

Results: A small callosal angle (CA), the Sylvian fissure dilatation, and absence of narrowing of superior parietal sulci discriminated the iNPH group from the hydrocephalus ex vacuo group (p<0.05). The final binary logistic regression model included narrowing of superior parietal sulci, degrees of the CA, and height of the Sylvian fissure after controlling for age and global Clinical Dementia Rating (CDR). The composite score made from these three indicators (narrowing of superior parietal sulci, degrees of the CA, and height of the Sylvian fissure) was statistically different between iNPH and hydrocephalus ex vacuo.

Conclusion: The narrowing of the CA, dilatation of the Sylvain fissure, and narrowing of superior parietal sulci may be used as radiological key indices and noninvasive tools for the differential diagnosis of iNPH from hydrocephalus ex vacuo.
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http://dx.doi.org/10.30773/pi.2020.0352DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8328827PMC
July 2021

Cochlear duct length and cochlear distance on preoperative CT: imaging markers for estimating insertion depth angle of cochlear implant electrode.

Eur Radiol 2021 Mar 20;31(3):1260-1267. Epub 2021 Jan 20.

Department of Radiology, Seoul National University Seoul Metropolitan Government Boramae Medical Center, Seoul, South Korea.

Objectives: Preoperative estimation of the insertion depth angle of cochlear implant (CI) electrodes is essential for surgical planning. The purpose of this study was to determine the cochlear size using preoperative CT and to investigate the correlation between cochlear size and insertion depth angle in morphologically normal cochlea.

Methods: Thirty-five children who underwent CI were included in this study. Cochlear duct length (CDL) and the diameter of the cochlear basal turn (distance A/B) on preoperative CT and the insertion depth angle of the CI electrode on postoperative radiographs were independently measured by two readers. Correlation between cochlear size and insertion depth angle was evaluated. Interobserver agreement was calculated using the intraclass correlation coefficient (ICC).

Results: The mean CDL, distance A, and distance B of 70 ears were 36.20 ± 1.57 mm, 8.67 ± 0.42 mm, and 5.73 ± 0.32 mm, respectively. The mean insertion depth angle was 431.45 ± 38.42°. Interobserver agreements of CDL, distance A/B, and insertion depth angle were fair to excellent (ICC 0.864, 0.862, 0.529, and 0.958, respectively). Distance A (r = - 0.7643) and distance B (r = - 0.7118) showed a negative correlation with insertion depth angle, respectively (p < 0.0001). However, the correlation between CDL and insertion depth angle was not statistically significant (r = - 0.2333, p > 0.05).

Conclusions: The CDL and cochlear distance can be reliably obtained from preoperative CT. Distance A can be used as a predictive marker for estimating insertion depth angle during CI surgery.
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http://dx.doi.org/10.1007/s00330-020-07580-4DOI Listing
March 2021

Relationship between Three-Dimensional Magnetic Resonance Imaging Eyeball Shape and Optic Nerve Head Morphology.

Ophthalmology 2021 04 8;128(4):532-544. Epub 2020 Sep 8.

Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea; Department of Ophthalmology, Seoul National University Boramae Medical Center, Seoul, Korea. Electronic address:

Purpose: To determine if the 3-dimensional (3D) eyeball shape is associated with the positions of the central retinal vascular trunk (CRVT) and the externally oblique border (EOB) in the optic nerve head (ONH).

Design: Prospective, cross-sectional study.

Participants: Fifty-six subjects (112 eyes) with a diagnosis of glaucoma or glaucoma suspect.

Methods: The eyeball shape on 3D magnetic resonance imaging (MRI) scans was classified according to the dimension of the longest diameter: axial dimension (prolate sphere), group 1; horizontal dimension (horizontally oblate sphere), group 2; and vertical dimension (vertically oblate sphere), group 3. The deviation of the CRVT, as a surrogate of lamina cribrosa (LC) shift, was measured from the center of the Bruch's membrane opening (BMO) demarcated by OCT imaging, with the horizontal midline as 0° and the superior location as a positive value. The angular location of the longest EOB was also measured.

Main Outcome Measure: Positions of CRVT and EOB according to the 3D eyeball shape.

Results: Among 112 eyes, 54 (48%) had a prolate shape (group 1), 23 (21%) had a horizontally oblate shape (group 2), and 35 (31%) had a vertically oblate shape (group 3). The angular deviation of the CRVT differed among the groups: to the nasal side in group 1, to the temporal side in group 2, and along the vertical meridian in group 3. In cases of asymmetric eyeball shape, the CRVT was deviated toward the undergrown side from the overgrown side, regardless of grouping. The angular location of the longest EOB was in the direction opposite to the CRVT position (P < 0.001). A generalized estimating equation analysis revealed that the temporal location of the CRVT was associated with older age (P = 0.001), nasal location of the longest EOB (P < 0.001), and oblate shape of the eyeball (P < 0.001, group 2; P = 0.007, group 3).

Conclusions: The position of the CRVT and EOB were associated with the 3D eyeball shape. Considering that infant ONH morphology is highly uniform, various modes of eyeball expansion during growth can result in diverse directionalities of offset between the LC and the BMO in adults.
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http://dx.doi.org/10.1016/j.ophtha.2020.08.034DOI Listing
April 2021

CT and MR imaging findings of ocular adnexal mucosa-associated lymphoid tissue lymphoma associated with IgG4-related disease: multi-institutional case series.

Int J Ophthalmol 2020 18;13(8):1231-1237. Epub 2020 Aug 18.

Department of Radiology, Inje University Haeundae Paik Hospital, Busan 47392, Republic of Korea.

Aim: To report CT and MR imaging findings of ocular adnexal mucosa-associated lymphoid tissue lymphoma associated with IgG4-related disease (IgG4-MALT lymphoma), a rare but clinically important complication of ocular adnexal IgG4-related disease.

Methods: We retrospectively reviewed all cases of histologically confirmed ocular adnexal IgG4-related disease at three tertiary and one secondary referral centers, between February 2003 and December 2016. Seven cases of histopathologically diagnosed IgG4-MALT lymphoma were identified. CT and MR images were analyzed by consensus of two experienced head and neck radiologists.

Results: Lacrimal glands were the main site of involvement in all seven patients. The lesions typically showed well-demarcated margins, iso- to hyperattenuation on precontrast CT, T2 hypo- to isointensity, T1 isointensity, and homogenous internal architecture with homogenous enhancement pattern. Lesions were mostly hyperdense and isointense to normal extraocular muscles on postcontrast CT and MR images, respectively.

Conclusion: Unlike in typical ocular adnexal IgG4-related disease, T2 isointensity and hyperattenuation on precontrast CT images were noted in some IgG4-MALT lymphoma cases. Although the findings may be nonspecific, the possibility of accompanying MALT lymphoma may need to be considered, when ocular adnexal lesions in patients clinically suspected of having IgG4-related disease are refractory to glucocorticoids and show T2 isointensity and hyperattenuation on precontrast CT for the optimal management of the patients. However, this is a case series of a very rare complication of ocular adnexal IgG4-related disease, and thus caution is warranted to generalize the conclusion.
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http://dx.doi.org/10.18240/ijo.2020.08.08DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7387900PMC
August 2020

Prognostic Value of Dynamic Contrast-Enhanced MRI-Derived Pharmacokinetic Variables in Glioblastoma Patients: Analysis of Contrast-Enhancing Lesions and Non-Enhancing T2 High-Signal Intensity Lesions.

Korean J Radiol 2020 06;21(6):707-716

Department of Radiology, Seoul National University Hospital, Seoul, Korea.

Objective: To evaluate pharmacokinetic variables from contrast-enhancing lesions (CELs) and non-enhancing T2 high signal intensity lesions (NE-T2HSILs) on dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging for predicting progression-free survival (PFS) in glioblastoma (GBM) patients.

Materials And Methods: Sixty-four GBM patients who had undergone preoperative DCE MR imaging and received standard treatment were retrospectively included. We analyzed the pharmacokinetic variables of the volume transfer constant (Ktrans) and volume fraction of extravascular extracellular space within the CEL and NE-T2HSIL of the entire tumor. Univariate and multivariate Cox regression analyses were performed using preoperative clinical characteristics, pharmacokinetic variables of DCE MR imaging, and postoperative molecular biomarkers to predict PFS.

Results: The increased mean Ktrans of the CEL, increased 95th percentile Ktrans of the CELs, and absence of methylated O⁶-methylguanine-DNA methyltransferase promoter were relevant adverse variables for PFS in the univariate analysis ( = 0.041, = 0.032, and = 0.083, respectively). The Kaplan-Meier survival curves demonstrated that PFS was significantly shorter in patients with a mean Ktrans of the CEL > 0.068 and 95th percentile Ktrans of the CEL>0.223 (log-rank = 0.038 and = 0.041, respectively). However, only mean Ktrans of the CEL was significantly associated with PFS ( = 0.024; hazard ratio, 553.08; 95% confidence interval, 2.27-134756.74) in the multivariate Cox proportional hazard analysis. None of the pharmacokinetic variables from NE-T2HSILs were significantly related to PFS.

Conclusion: Among the pharmacokinetic variables extracted from CELs and NE-T2HSILs on preoperative DCE MR imaging, the mean Ktrans of CELs exhibits potential as a useful imaging predictor of PFS in GBM patients.
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http://dx.doi.org/10.3348/kjr.2019.0629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7231611PMC
June 2020

Development of Quality-Controlled Low-Dose Protocols for Radiography in the Neonatal ICU Using a New Mobile Digital Radiography System.

AJR Am J Roentgenol 2020 08 14;215(2):488-493. Epub 2020 May 14.

Department of Radiology, Seoul National University, Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea.

The aim of this study was to develop a low-dose radiography protocol for the neonatal ICU (NICU) using a new mobile digital radiography system with advanced denoising image processing and to evaluate the noninferiority of that protocol. In this prospective randomized study, 40 neonates in the NICU underwent radiography of the thorax and abdomen with two different mobile radiography units: conventional technique on one unit (50 kV, 1.6 mAs, and no additional filtration) and a new technique on another unit (54 kV, 0.1-mm Cu filtration). Three low-dose protocols for the second unit were developed in a phantom study: protocol A (100% equivalent dose with conventional protocol), protocol B (80% equivalent dose), and protocol C (64% equivalent dose). The noninferiority of each low-dose protocol was assessed by three independent readers using image quality criteria. Forty patients each underwent three pairs of radiography examinations (protocol A and the conventional protocol, protocol B and the conventional protocol, and protocol C and the conventional protocol), except one pair that did not include one image of the conventional protocol. The interrater reliability among the three readers was 0.91 ( < 0.001). Both of the low-dose protocols (B and C) were statistically noninferior to the conventional protocol with respect to overall image quality. Protocol B better depicted almost all anatomic landmarks and had better overall image quality than the conventional protocol. Using appropriate technique and acquisition factors, radiation dose can be lowered on a digital radiography system without significant effect on the image quality by adding filtrations and a new denoising technique.
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http://dx.doi.org/10.2214/AJR.19.22269DOI Listing
August 2020

Added Value of Computed Tomography to Ultrasonography for Assessing LN Metastasis in Preoperative Patients with Thyroid Cancer: Node-By-Node Correlation.

Cancers (Basel) 2020 May 8;12(5). Epub 2020 May 8.

Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 03080, Korea.

Diagnostic accuracy of US in the evaluation of lymph node (LN) metastasis for thyroid cancer patients is limited. We investigated the value of CT added to US for characterizing LNs in preoperative thyroid cancer patients by node-by-node correlation. A total of 225 primary thyroid cancer patients who underwent LN biopsy were included. Based on node-by-node correlation, 274 LNs were classified into probably benign, indeterminate, and suspicious categories on US, CT, and combined US/CT. Malignancy risks were calculated for each category and were compared between US/CT concordant and discordant cases. On US, CT, and combined US/CT, malignancy risks were 1.7%, 8.7%, and 0% in the probably benign category, 22.4%, 5.9%, and 8.0% in the indeterminate category, and 77.2%, 82.0%, and 75.6% in the suspicious category, respectively. Malignancy risk of the concordant suspicious category was higher than that of the discordant suspicious category (84.7% vs. 43.2%, < 0.001). The addition of CT helped correctly detect additional metastasis in 16.4% of the US indeterminate LNs and in 1.7% of the US probably benign LNs. CT may complement US for LN characterization in thyroid cancer patients by suggesting the diagnostic confidence level for the suspicious category and helping correctly detect metastasis in US indeterminate LNs.
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http://dx.doi.org/10.3390/cancers12051190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7281101PMC
May 2020

Ultrasonographic Indeterminate Lymph Nodes in Preoperative Thyroid Cancer Patients: Malignancy Risk and Ultrasonographic Findings Predictive of Malignancy.

Korean J Radiol 2020 05;21(5):598-604

Department of Radiology, Seoul National University College of Medicine, Seoul, Korea.

Objective: Proper management of lymph nodes (LNs) with ultrasonographic (US) indeterminate features in thyroid cancer patients remains elusive. We aimed to evaluate the malignancy risk and US findings predictive of malignancy for US indeterminate LNs in preoperative thyroid cancer patients through node-by-node correlation.

Materials And Methods: A total of 348 LNs in 284 thyroid cancer patients, who underwent fine-needle aspiration or core-needle biopsy between December 2006 and June 2015, were included. We determined the malignancy risks for US probably benign, indeterminate, and suspicious categories. For US indeterminate LNs, which had neither echogenic hilum nor hilar vascularity in the absence of any suspicious finding, US findings were compared between benign and metastatic LNs using Mann-Whitney U test and Fisher's exact test.

Results: US imaging diagnoses were probably benign in 20.7% (n = 72) cases, indeterminate in 23.6% (n = 82), and suspicious in 55.7% (n = 194). Malignancy risk of US indeterminate LNs (19.5% [16/82]) differed from those of the US probably benign (2.8% [2/72]) ( = 0.002) and US suspicious LNs (78.4% [152/194]) ( < 0.001). Among US indeterminate LNs, there were no significant differences in short, long, and long-to-short diameter (L/S) ratios between benign and metastatic LNs (3.9 vs. 3.8 mm, = 0.619; 7.3 vs. 7.3 mm, = 0.590; 1.9 vs. 1.9, = 0.652).

Conclusion: US indeterminate LNs were frequently encountered during preoperative evaluation and had intermediate malignancy risk. Given the lack of discriminative power of size criteria and L/S ratio, clinical factors such as surgical strategy and node size should be considered for proper triage of US indeterminate LNs in thyroid cancer.
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http://dx.doi.org/10.3348/kjr.2019.0755DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7183832PMC
May 2020

Ivy Sign Predicts Ischemic Stroke Recurrence in Adult Moyamoya Patients without Revascularization Surgery.

Cerebrovasc Dis 2019 18;47(5-6):223-230. Epub 2019 Jun 18.

Department of Neurosurgery, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Republic of Korea.

Background: Although there is a standard guideline for performing revascularization surgery in patients with Moyamoya diseases (MMD), more objective and easily obtainable predictors are still needed.

Objectives: In this study, we aimed to evaluate the relationship between an ipsilateral ivy sign and ischemic stroke recurrence in adult MMD patients without revascularization surgery.

Methods: We included consecutive MMD patients without revascularization surgery between 2006 and 2014. The ivy sign was defined as a linear or focal high-signal intensity on fluid-attenuated inversion recovery images, and the burdens of ivy sign were rated in each hemisphere. The ischemic stroke recurrence was defined as a new clinical event that accompanied a new brain lesion on magnetic resonance imaging.

Results: Overall, 84 patients with 154 hemispheres were analyzed. We found recurrent ischemic stroke in 9 (6%) hemispheres within 3 years. In multivariate analysis, an ipsilateral ivy sign remained an independent predictor of 3-year ischemic recurrence (adjusted hazard ratio [aHR] 10.15, 95% CI 2.10-49.14, p = 0.004). An initial presentation as infarction was also significant (aHR 7.15, 95% CI 1.36-36.78, p = 0.019). The burdens of ivy sign showed a dose-response tendency with the 3-year ischemic recurrence rate (p < 0.001). When comparing the ischemic recurrence rate among 4 groups with and without ivy sign and perfusion defect, the "Ivy sign (+) Perfusion defect (+) group" showed a significantly higher risk in both observed (p = 0.005) and estimated (p = 0.003) 3-year ischemic recurrence than did the other group. Additionally, the "Ivy sign (+) Perfusion defect (-) group" showed a higher recurrence rate than did the "Ivy sign (-) Perfusion defect (+) group".

Conclusions: The ivy sign is associated with ischemic recurrence in adult MMD patients in a dose-response manner. It would be helpful for selecting high-risk patients who need revascularization surgery.
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http://dx.doi.org/10.1159/000500610DOI Listing
May 2020

Ultrasound image analysis using deep learning algorithm for the diagnosis of thyroid nodules.

Medicine (Baltimore) 2019 Apr;98(15):e15133

Department of Surgery, Kuma Hospital, Kobe, Japan.

Fine needle aspiration (FNA) is the procedure of choice for evaluating thyroid nodules. It is indicated for nodules >2 cm, even in cases of very low suspicion of malignancy. FNA has associated risks and expenses. In this study, we developed an image analysis model using a deep learning algorithm and evaluated if the algorithm could predict thyroid nodules with benign FNA results.Ultrasonographic images of thyroid nodules with cytologic or histologic results were retrospectively collected. For algorithm training, 1358 (670 benign, 688 malignant) thyroid nodule images were input into the Inception-V3 network model. The model was pretrained to classify nodules as benign or malignant using the ImageNet database. The diagnostic performance of the algorithm was tested with the prospectively collected internal (n = 55) and external test sets (n = 100).For the internal test set, 20 of the 21 FNA malignant nodules were correctly classified as malignant by the algorithm (sensitivity, 95.2%); and of the 22 nodules algorithm classified as benign, 21 were FNA benign (negative predictive value [NPV], 95.5%). For the external test set, 47 of the 50 FNA malignant nodules were correctly classified by the algorithm (sensitivity, 94.0%); and of the 31 nodules the algorithm classified as benign, 28 were FNA benign (NPV, 90.3%).The sensitivity and NPV of the deep learning algorithm shown in this study are promising. Artificial intelligence may assist clinicians to recognize nodules that are likely to be benign and avoid unnecessary FNA.
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http://dx.doi.org/10.1097/MD.0000000000015133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6485748PMC
April 2019

MRI Findings of Spontaneous Intracranial Hypotension: Usefulness of Straight Sinus Distention.

AJR Am J Roentgenol 2019 Feb 26:1-7. Epub 2019 Feb 26.

3 Department of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.

Objective: Spontaneous intracranial hypotension (SIH) shows various characteristic MRI findings. We evaluated the usefulness of straight sinus distention compared with transverse sinus distention and also evaluated other MRI findings of SIH.

Materials And Methods: Forty-three consecutive patients (28 female and 15 male patients) treated for SIH and 43 age- and sex-matched control subjects at two institutions from 2012 through 2014 were included in this study. Two reviewers determined whether the transverse sinus distention sign and straight sinus distention sign were present on MRI. Diagnostic performance values and interobserver agreement were calculated. Reviewers also assessed MRI examinations in consensus for the presence of the following findings: pachymeningeal enhancement, subdural effusion or hematoma, enlargement of the pituitary gland, and downward displacement of the brainstem and tonsils.

Results: The sensitivity, specificity, and diagnostic accuracy of the transverse sinus distention sign for SIH were 76.7%, 83.7%, and 80.2%, whereas those of the straight sinus distention sign were 79.1%, 95.4%, and 87.2%, respectively. The specificity of the straight sinus distention sign for SIH was significantly higher (p = 0.025) than that of the transverse sinus distention sign. In addition, the straight sinus distention sign showed substantial agreement (κ = 0.79), whereas the transverse sinus distention sign showed moderate agreement (κ = 0.60). The diagnostic accuracy of the presence of either transverse or straight sinus distention (83.7%) was significantly higher than that of pachymeningeal enhancement (80.2%, p = 0.032).

Conclusion: The straight sinus distention sign could be helpful for the diagnosis of SIH because it has sensitivity comparable to other imaging findings and higher specificity and higher level of interobserver agreement than other imaging findings.
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http://dx.doi.org/10.2214/AJR.18.20369DOI Listing
February 2019

Persistent/Recurrent Differentiated Thyroid Cancer: Clinical and Radiological Characteristics of Persistent Disease and Clinical Recurrence Based on Computed Tomography Analysis.

Thyroid 2018 11 16;28(11):1490-1499. Epub 2018 Oct 16.

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

Background: The natural course of persistent/recurrent differentiated thyroid cancer (DTC) has not been fully elucidated. The purpose of this study was to assess the relative incidence and clinico-radiological characteristics of persistent disease and clinical recurrence based on computed tomography (CT) analysis in patients with persistent/recurrent DTC.

Methods: From January 2005 to December 2016, this retrospective study included 107 patients (M:F = 28:79; M = 53.5 years) with surgically proven cervical locoregional recurrence of DTC. Two neck CT examinations (median interval 1.92 years; range 0.17-7.58 years) before the last thyroid cancer surgery within the study period were reevaluated. Based on the presence of the lesion on the first CT and its progression on the second CT, the locoregional recurrence was classified into the following categories: stable persistence (decrease, no change, or increase by <2 mm in short dimension on the second CT), progressive persistence (increase by ≥2 mm), and clinical recurrence (newly appeared on the second CT). Clinical and radiological characteristics of the three groups were compared using univariate and multivariate logistic regression analyses.

Results: The relative incidences of stable persistence, progressive persistence, and clinical recurrence were 56.1% (60/107), 15.0% (16/107), and 29.0% (31/107), respectively. Multivariate analysis between the clinical recurrence (29.0%) and persistence (71.0%) groups revealed various independent factors for prediction of clinical recurrence. These included longer interval between the two CT examinations (median 2.67 vs. 1.79 years; p = 0.021), a smaller number of thyroid surgeries (1.16 ± 0.45 vs. 1.55 ± 0.81; p = 0.002), and a history of neck dissection at the location of the largest locoregional recurrence (70.0% vs. 31.4%; p < 0.001). There was no significant independent factor for differentiation between the stable persistence (78.9%; 60/76) and progressive persistence (21.1%; 16/76) groups. The results may have been influenced by selection bias because this study included only surgically proven cases.

Conclusions: With regard to cervical locoregional recurrence of DTC, active surveillance may be favored because more than a half of the cases are structurally persistent and stable. However, meticulous evaluation is necessary to detect progressive persistence and clinical recurrence, considering various clinical factors.
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http://dx.doi.org/10.1089/thy.2018.0151DOI Listing
November 2018

A quick test of cognitive speed in older adults with Alzheimer's disease and mild cognitive impairment: A preliminary behavioral and brain imaging study.

Psychiatry Res Neuroimaging 2018 10 9;280:30-38. Epub 2018 Aug 9.

Department of Psychiatry, SMG-SNU Boramae Medical Center, Seoul, Republic of Korea; Department of Psychiatry and Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. Electronic address:

The purpose of this study was to assess scores and processing speed distributions of the instrument, A Quick Test of Cognitive Speed (AQT), in Korean older adults through behavioral and brain imaging approaches. Participants were instructed to say the color names, stimuli's form, and both the color and form. Test scores and processing speeds were measured in these three subtests of color, form, and color-form. A total of 67 patients (22 healthy controls (HC), 22 with mild cognitive impairment (MCI), and 23 with Alzheimer's disease (AD)) participated. Only color-form score and processing speed of the three subtests could be used to differentiate AD from MCI and HC. Color-form score showed the largest effects size (partial η = 0.268) for distinguishing AD, MCI from HC and ROC curve analysis confirmed a high level of sensitivity (0.857) and specificity (0.826) for discrimination between AD and HC. None of the subtests could differentiate HC from MCI. Voxel-based morphometry analysis of brain structure in 27 participants (9 in each group) revealed that gray matter volume of the middle occipital gyrus and inferior parietal cortex were associated with color-form score. This study suggests preliminary evidence in the clinical utility of the AQT for screening AD in older Korean adults. The color-form score could be implemented for clinical utilization in a very brief time. Furthermore, strong positive correlations between color-form scores and the brain areas responsible for visuospatial working memory corroborate the validity of AQT.
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http://dx.doi.org/10.1016/j.pscychresns.2018.08.004DOI Listing
October 2018

Significance of distance between tumor and thyroid capsule as an indicator for central lymph node metastasis in clinically node negative papillary thyroid carcinoma patients.

PLoS One 2018 17;13(7):e0200166. Epub 2018 Jul 17.

Department of Internal Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea.

The aim of this study was to evaluate preoperatively identifiable clinical and ultrasonographic characteristics associated with central lymph node metastasis (CLNM) in clinically node negative papillary thyroid carcinoma (PTC) patients. Records of the patients who underwent thyroidectomy with prophylactic central lymph node dissection due to clinically node negative PTC (size, 1.0-3.0 cm) were reviewed. Of a total of 174 patients, 71 (40.8%) had CLNMs. CLNM was more associated with capsule invasion than capsule non-invasion on ultrasonography (68.4% vs. 37.4%, p = 0.009). In the 155 patients without capsule invasion, a distance from the capsule < 1.9 mm was associated with CLNM in univariable (p = 0.002) and multivariable analysis (p < 0.001). Any PTC patient with a distance from the capsule ≥ 1.9 mm did not have CLNM whereas 40.8% (58/142) of PTC patients with a distance from the capsule < 1.9 mm had CLNM. CLNM was not associated with age, gender, or tumor size on ultrasonography. Distance from capsule ≥ 1.9 mm on preoperative ultrasonography was a significant indicator for not having CLNM in clinically node negative PTC patients. Measuring distance from the capsule on preoperative ultrasonography images could help select patients with PTC who could benefit from prophylactic central lymph node dissection.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0200166PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6049913PMC
January 2019

PREDICTION OF NONDIAGNOSTIC RESULTS IN FINE-NEEDLE ASPIRATION OF THYROID NODULES: UTILITY OF ON-SITE GROSS VISUAL ASSESSMENT OF SPECIMENS FOR LIQUID-BASED CYTOLOGY.

Endocr Pract 2018 Oct 5;24(10):867-874. Epub 2018 Jul 5.

Objective: To explore a comprehensive approach for on-site gross visual assessments of liquid-based cytology (LBC) specimens of thyroid nodules and determine morphologic criteria that help predict nondiagnostic rates.

Methods: Two-hundred nodules from 165 patients who underwent fine-needle aspiration (FNA) at our hospital were included in this prospectively designed, retrospective analysis. Specimens were visually assessed on-site for three morphologic categories (specimen color, specimen volume, and particle count) using a 5-point grading.

Results: Twenty-two nodules (11%) showed nondiagnostic results. Regarding specimen color, nondiagnostic rates tended to be higher in grades 1 (75%) and 5 (100%) than in grades 2 (18%), 3 (8%), or 4 (17%), with a significant difference between grade 1 and grade 3 ( P = .003). For specimen volume, nondiagnostic results were significantly more common in grade 1 (33%) and 5 (33%) than in grades 3 (5%) or 4 (1%) ( P<.005). There was a significant negative correlation between the grading of the particle count and the nondiagnostic rate (Spearman ρ = -1.000; P<.001). The sensitivity and specificity in the prediction of nondiagnostic results were 77% and 76%, respectively, at the optimal cutoff value of 2 (grade 2 or lower).

Conclusion: Particle count was an important morphologic criterion that helped predict nondiagnostic rates in LBC specimens of thyroid nodules, and the specimen color and volume were also useful adjuncts. In routine practice, on-site gross visual assessment followed by resampling (if necessary) may potentially help reduce the rates of nondiagnostic results, repeat FNAs, and the number of unnecessary needle passes.

Abbreviations: FNA = fine-needle aspiration; LBC = liquid-based cytology; ROC = receiver operating characteristic; US = ultrasonography.
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http://dx.doi.org/10.4158/EP-2018-0183DOI Listing
October 2018

Metal Artifact Reduction for Orthopedic Implants: Brain CT Angiography in Patients with Intracranial Metallic Implants.

J Korean Med Sci 2018 May 2;33(21):e158. Epub 2018 May 2.

Department of Radiology, Seoul National University Hospital, Healthcare System Gangnam Center, Seoul, Korea.

Background: The purpose of this study was to qualitatively and quantitatively evaluate the effects of a metal artifact reduction for orthopedic implants (O-MAR) for brain computed tomographic angiography (CTA) in patients with aneurysm clips and coils.

Methods: The study included 36 consecutive patients with 47 intracranial metallic implants (42 aneurysm clips, 5 coils) who underwent brain CTA. The computed tomographic images with and without the O-MAR were independently reviewed both quantitatively and qualitatively by two reviewers. For quantitative analysis, image noises near the metallic implants of non-O-MAR and O-MAR images were compared. For qualitative analysis, image quality improvement and the presence of new streak artifacts were assessed.

Results: Image noise was significantly reduced near metallic implants ( < 0.01). Improvement of implant-induced streak artifacts was observed in eight objects (17.0%). However, streak artifacts were aggravated in 11 objects (23.4%), and adjacent vessel depiction was worsened in eight objects (17.0%). In addition, new O-MAR-related streak artifacts were observed in 32 objects (68.1%). New streak artifacts were more prevalent in cases with overlapping metallic implants on the same axial plane than in those without ( = 0.018). Qualitative assessment revealed that the overall image quality was not significantly improved in O-MAR images.

Conclusion: In conclusion, the use of the O-MAR in patients with metallic implants significantly reduces image noise. However, the degree of the streak artifacts and surrounding vessel depiction were not significantly improved on O-MAR images.
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http://dx.doi.org/10.3346/jkms.2018.33.e158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5955738PMC
May 2018

Acute invasive fungal rhinosinusitis: MR imaging features and their impact on prognosis.

Neuroradiology 2018 Jul 17;60(7):715-723. Epub 2018 May 17.

Department of Radiology, GangNeung Asan Hospital, GangNeung, South Korea.

Purpose: Acute invasive fungal rhinosinusitis (AIFRS) is a life-threatening disease that is difficult to diagnose. Its overall imaging features have not been evaluated and the prognostic impact is unclear. The purpose of our study was to present MR imaging features and their impact on prognosis of AIFRS.

Methods: MR images and clinical records of 23 patients with AIFRS were retrospectively evaluated to identify the imaging features and to determine the factors affecting patients' survival. A multivariable Cox proportional hazard model was used to estimate the hazard ratio of the prognostic factors, and Kaplan-Meier survival curves were compared by using a log-rank test.

Results: All cases showed extra-sinonasal involvement and the orbit was the most common (65.2%, 15/23) location. The lesion enhancement pattern was classified into lack of contrast enhancement (LoCE) (47.8%, 11/23) and homogeneous (34.8%, 8/23) and heterogeneous (17.4%, 4/23) enhancement. Although LoCE showed variable signal intensity (SI), homogeneously or heterogeneously enhancing lesions showed exclusively low SI (100%, 12/12) on T2WI. Among various clinical and imaging factors, LoCE was correlated with coagulation necrosis, probably provoked by numerous fungal hyphae, and was found to be a sole independent prognostic factor for disease-specific mortality (hazard ratio = 16.819; 95% CI, 1.646-171.841, p = 0.017). In addition, patients with LoCE showed worse survival than patients without LoCE (p = 0.008).

Conclusion: AIFRS showed frequent extra-sinonasal involvement and variable MR enhancement patterns. An enhancement pattern of LoCE was seen in about half of the cases and was a unique prognostic factor among the various clinico-radiologic factors.
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http://dx.doi.org/10.1007/s00234-018-2034-0DOI Listing
July 2018

Value of CT added to ultrasonography for the diagnosis of lymph node metastasis in patients with thyroid cancer.

Head Neck 2018 10 13;40(10):2137-2148. Epub 2018 May 13.

Department of Radiology, Gang Neung Asan Hospital, Gangneung-si, Korea.

Background: The benefit of CT for the diagnosis of lymph node metastasis in patients with thyroid cancer is still unclear.

Methods: Three hundred fifty-one patients with thyroid cancers from 7 hospitals were prospectively enrolled in order to compare diagnostic performance between a combination of ultrasound and CT (ultrasound/CT) and ultrasound alone for prediction of lymph node metastasis and to calculate patient-based benefits of CT added to ultrasound.

Results: Of 801 pathologically proven neck levels, ultrasound/CT showed higher sensitivities in both central and lateral compartments and improved accuracy in the lateral compartment compared to ultrasound alone. In the retropharyngeal/superior mediastinal compartment, although CT could detect lymph node metastasis an ultrasound could not. Patient-based benefit was demonstrated in 13.1% of patients (46/351), and was higher in patients with cancers >1 cm than cancers ≤1 cm.

Conclusion: In patients with thyroid cancer, CT improved surgical planning by enhancing the sensitivity for lymph node metastasis and by detecting lymph node metastasis that was overlooked with ultrasound alone.
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http://dx.doi.org/10.1002/hed.25202DOI Listing
October 2018

Patterns of Progressive Ganglion Cell-Inner Plexiform Layer Thinning in Glaucoma Detected by OCT.

Ophthalmology 2018 10 25;125(10):1515-1525. Epub 2018 Apr 25.

Department of Radiology, Seoul National University College of Medicine, Seoul, Korea; Department of Radiology, Seoul Metropolitan Government Seoul National University, Boramae Medical Center, Seoul, Korea. Electronic address:

Purpose: To investigate the spatial characteristics and patterns of progressive macular ganglion cell-inner plexiform layer (GCIPL) thinning in glaucomatous eyes assessed by OCT Guided Progression Analysis (GPA).

Design: Longitudinal, retrospective, observational study.

Participants: Two hundred ninety-two eyes of 192 patients with primary open-angle glaucoma with a mean follow-up of 6.0 years (range, 3.2-8.1 years) were included.

Methods: Macular GCIPL imaging and visual field (VF) examination were performed at 6-month intervals for 3 years or more. Progressive GCIPL thinning was evaluated by a Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA) GPA device. Spatial characteristics of progressive GCIPL thinning were assessed by the GCIPL thickness change map. The pattern of progressive GCIPL thinning was evaluated by comparing the baseline GCIPL thickness deviation map and the final GCIPL thickness change map. Visual field progression was determined by Early Manifest Glaucoma Trial criteria and linear regression of the VF index.

Main Outcome Measures: Spatial characteristics and patterns of progressive GCIPL thinning.

Results: Seventy-two eyes of 62 participants (24.7% [72/292]) showed progressive GCIPL thinning in the GCIPL thickness change map. Progressive GCIPL thinning was detected most frequently (25.0%) at 2.08 mm from the fovea, and it extended in an arcuate shape in the inferotemporal region (250°-339°). Compared with the baseline GCIPL defects, the progressive GCIPL thinning extended toward the fovea and optic disc. The most common pattern of progressive GCIPL thinning was widening of GCIPL defects (42 eyes [58.3%]), followed by deepening of GCIPL defects (19 eyes [26.4%]) and newly developed GCIPL defects (15 eyes [20.8%]). Visual field progression was accompanied by progressive GCIPL thinning in 41 of 72 eyes (56.9%). Progressive GCIPL thinning preceded (61.0% [25/41]) or occurred concomitantly with (21.9% [9/41]) VF progression.

Conclusions: The use of OCT GPA maps offers an effective approach to evaluate the topographic patterns of progressive GCIPL thinning in glaucomatous eyes. Progression of GCIPL thinning occurred before apparent progression on standard automated perimetry in most glaucomatous eyes. Understanding specific patterns and sequences of macular damage may provide important insights in the monitoring of glaucomatous progression.
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http://dx.doi.org/10.1016/j.ophtha.2018.03.052DOI Listing
October 2018

Non-Motor Symptom Burdens Are Not Associated with Iron Accumulation in Early Parkinson's Disease: a Quantitative Susceptibility Mapping Study.

J Korean Med Sci 2018 Mar 26;33(13):e96. Epub 2018 Mar 26.

Department of Radiology, Seoul National University-Seoul Metropolitan Government Boramae Medical Center, Seoul, Korea.

Background: Quantitative susceptibility mapping (QSM) has been used to measure iron accumulation in the deep nuclei of patients with Parkinson's disease (PD). This study examined the relationship between non-motor symptoms (NMSs) and iron accumulation in the deep nuclei of patients with PD.

Methods: The QSM data were acquired from 3-Tesla magnetic resonance imaging (MRI) in 29 patients with early PD and 19 normal controls. The Korean version of the NMS scale (K-NMSS) was used for evaluation of NMSs in patients. The patients were divided into high NMS and low NMS groups. The region-of-interest analyses were performed in the following deep nuclei: red nucleus, substantia nigra pars compacta, substantia nigra pars reticulata, dentate nucleus, globus pallidus, putamen, and head of the caudate nucleus.

Results: Thirteen patients had high NMS scores (total K-NMSS score, mean = 32.1), and 16 had low NMS scores (10.6). The QSM values in the deep were not different among the patients with high NMS scores, low NMS scores, and controls. The QSM values were not correlated linearly with K-NMSS total score after adjusting the age at acquisition of brain MRI.

Conclusion: The study demonstrated that the NMS burdens are not associated with iron accumulation in the deep nuclei of patients with PD. These results suggest that future neuroimaging studies on the pathology of NMSs in PD should use more specific and detailed clinical tools and recruit PD patients with severe NMSs.
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http://dx.doi.org/10.3346/jkms.2018.33.e96DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5865060PMC
March 2018

Transit time corrected arterial spin labeling technique aids to overcome delayed transit time effect.

Neuroradiology 2018 Mar 29;60(3):255-265. Epub 2017 Dec 29.

GE Healthcare Canada, Calgary, Canada.

Purpose: This study aimed to evaluate the usefulness of transit time corrected cerebral blood flow (CBF) maps based on multi-phase arterial spin labeling MR perfusion imaging (ASL-MRP).

Methods: The Institutional Review Board of our hospital approved this retrospective study. Written informed consent was waived. Conventional and multi-phase ASL-MRPs and dynamic susceptibility contrast MR perfusion imaging (DSC-MRP) were acquired for 108 consecutive patients. Vascular territory-based volumes of interest were applied to CBF and time to peak (TTP) maps obtained from DSC-MRP and CBF maps obtained from conventional and multi-phase ASL-MRPs. The concordances between normalized CBF (nCBF) from DSC-MRP and nCBF from conventional and transition time corrected CBF maps from multi-phase ASL-MRP were evaluated using Bland-Altman analysis. In addition, the dependence of difference between nCBF (ΔnCBF) values obtained from DSC-MRP and conventional ASL-MRP (or multi-phase ASL-MRP) on TTP obtained from DSC-MRP was also analyzed using regression analysis.

Results: The values of nCBFs from conventional and multi-phase ASL-MRPs had lower values than nCBF based on DSC-MRP (mean differences, 0.08 and 0.07, respectively). The values of ΔnCBF were dependent on TTP values from conventional ASL-MRP technique (F = 5.5679, P = 0.0384). No dependency of ΔnCBF on TTP values from multi-phase ASL-MRP technique was revealed (F = 0.1433, P > 0.05).

Conclusion: The use of transit time corrected CBF maps based on multi-phase ASL-MRP technique can overcome the effect of delayed transit time on perfusion maps based on conventional ASL-MRP.
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http://dx.doi.org/10.1007/s00234-017-1969-xDOI Listing
March 2018

Risk factors for extraophthalmic involvement and treatment outcomes in patients with IgG4-related ophthalmic disease.

Br J Ophthalmol 2018 06 28;102(6):736-741. Epub 2017 Sep 28.

Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea.

Background/aim: To analyse the clinical risk factors for extraophthalmic involvement and treatment outcomes in patients with IgG4-related ophthalmic disease (IgG4-ROD) in Korea.

Methods: We retrospectively reviewed medical records of 42 patients diagnosed with IgG4-ROD confirmed by a surgical biopsy during the 7-year period, between January 2009 and March 2015, at three tertiary referral centres in Korea. Data regarding patients' demographics, clinical characteristics and radiological findings were obtained. The relapse rate was compared between systemic steroids only and combined immunosuppressant therapy.

Results: The mean patient age was 55.2 years (male:female ratio, 1:1). Based on the primary orbital structure affected, the IgG4-RODs were classified as dacryoadenitis (52.4%), orbital soft tissue inflammation (21.4%), trigeminal nerve involvement (11.9%) and myositis (9.5%). Extraophthalmic involvement (n=21) was associated with bilateral involvement (p=0.004), longer symptom duration (p=0.033) and a higher serum IgG4 level (p=0.034). Initial treatment regimens included attentive observation (n=7), prednisolone alone (n=22) and prednisolone plus immunosuppressive agent (n=13). During follow-up (mean, 24 months), 13 patients (37.1%) experienced relapse. In the extraophthalmic involvement group, steroid therapy alone resulted in a significantly higher relapse rate than combined immunosuppressant treatment (p=0.028).

Conclusion: Bilateral involvement, longer symptom duration and higher IgG4 levels were significant risk factors for extraophthalmic involvement in Korean patients with IgG4-ROD. In patients with an extraophthalmic involvement, prednisolone combined with an immunosuppressive agent was more effective for preventing recurrence than prednisolone alone.
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http://dx.doi.org/10.1136/bjophthalmol-2017-310584DOI Listing
June 2018

Evaluation of Gadolinium Retention After Serial Administrations of a Macrocyclic Gadolinium-Based Contrast Agent (Gadobutrol): A Single-Institution Experience With 189 Patients.

Invest Radiol 2018 01;53(1):20-25

Objective: There has been controversy as to whether gadobutrol, one of the widely used macrocyclic gadolinium-based contrast agents, can lead to gadolinium retention after serial injections. Our aim was to validate whether serial administrations of gadobutrol can cause signal increase in the dentate nucleus (DN) and globus pallidus (GP) on unenhanced T1-weighted magnetic resonance (MR) images due to gadolinium retention.

Materials And Methods: A total of 189 patients who had undergone at least 2 contrast-enhanced MR scans using only gadobutrol between August 2009 and August 2016 were retrospectively included. The DN-to-pons and GP-to-thalamus signal intensity (SI) ratio differences on unenhanced T1-weighted MR images were calculated by subtracting the SI ratios at the first MR images from those at the last MR images. One-sample t tests were used to evaluate whether the SI ratio differences differed from 0. Linear regression and Pearson correlations were performed to assess correlations between SI ratio differences and various confounding variables, including the number of MR scans, mean time interval between MR scans, age, sex, history of radiation therapy or chemotherapy, and renal and liver functions.

Results: Patients underwent a mean of 5.9 ± 6.3 contrast-enhanced MR scans with a mean interval of 42.8 ± 49.5 weeks between the scans. Sixty-three patients underwent 6 or more MR scans, whereas 126 patients underwent fewer than 6 MR scans. Neither the DN-to-pons SI nor the GP-to-thalamus SI ratio differences differed significantly from 0, with mean values of -0.012 ± 0.115 (P = 0.148) and 0.012 ± 0.111 (P = 0.126), respectively.

Conclusions: Serial administrations of gadobutrol did not result in signal increases in the DN or GP on unenhanced T1-weighted MR images due to gadolinium retention.
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http://dx.doi.org/10.1097/RLI.0000000000000404DOI Listing
January 2018

Temporal bone chondroblastoma: Imaging characteristics with pathologic correlation.

Head Neck 2017 11 24;39(11):2171-2179. Epub 2017 Jul 24.

Department of Radiology, Seoul National University Hospital, Seoul, Korea.

Background: Chondroblastoma commonly involves the temporal bone in the craniofacial region, but its imaging features have not been elucidated. This study aimed to describe the imaging features of temporal bone chondroblastoma with their pathologic correlation.

Methods: Radiopathologic correlation was performed in 5 patients with temporal bone chondroblastoma from our database and in 11 patients identified through a PubMed search.

Results: The cases of temporal bone chondroblastoma commonly involve the squamous part, temporal and infratemporal fossae, temporomandibular joint, and tympanic cavity, with the following features: high attenuation with calcification; heterogeneity; low signal intensity on T2-weighted imaging with enhancement; a smooth interface to the brain; and strong hypermetabolism on fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT. The heterogeneous low signal intensity on T2-weighted imaging was correlated with various histopathologic components, including calcification and hemosiderin deposition.

Conclusion: Temporal bone chondroblastoma usually forms as an expansile, heterogeneous, hypermetabolic mass in the middle cranial fossa, frequently with low signal intensity on T2-weighted imaging, reflecting various degrees of calcification and hemosiderin deposition.
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http://dx.doi.org/10.1002/hed.24880DOI Listing
November 2017

Altered hippocampal volume and functional connectivity in males with Internet gaming disorder comparing to those with alcohol use disorder.

Sci Rep 2017 07 18;7(1):5744. Epub 2017 Jul 18.

Department of Nuclear Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, 07061, Republic of Korea.

Internet gaming disorder (IGD) has been conceptualized as a behavioral addiction and shares clinical, neuropsychological, and personality characteristics with alcohol use disorder (AUD), but IGD dose not entail brain exposure to toxic agents, which renders it different from AUD. To achieve a clear understanding of the neurobiological features of IGD, we aimed to identify morphological and functional changes in IGD and compare them with those in AUD. Individuals with IGD showed larger volume in the hippocampus/amygdala and precuneus than healthy controls (HCs). The volume in the hippocampus positively correlated with the symptom severity of IGD. Moreover, functional connectivity analysis with the hippocampus/amygdala cluster revealed that the left ventromedial prefrontal cortex showed stronger functional connectivity in individuals with IGD compared to those with AUD. In contrast, individuals with AUD exhibited the smaller cerebellar volume and thinner medial frontal cortex than HCs. The volume in the cerebellum correlated with impaired working memory function as well as duration of illness in AUD group. Findings suggested that altered volume and functional connectivity in the hippocampus/amygdala in IGD might be associated with abnormally enhanced memory process of gaming-related cues, while abnormal cortical changes and cognitive impairments in AUD might be associated with neurotoxic effects of alcohol.
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http://dx.doi.org/10.1038/s41598-017-06057-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5515845PMC
July 2017

Detection of crossed cerebellar diaschisis in hyperacute ischemic stroke using arterial spin-labeled MR imaging.

PLoS One 2017 21;12(3):e0173971. Epub 2017 Mar 21.

Department of Radiology, Seoul National University Boramae Hospital, Seoul, Republic of Korea.

Background And Purpose: Arterial spin-labeling (ASL) was recently introduced as a noninvasive method to evaluate cerebral hemodynamics. The purposes of this study were to assess the ability of ASL imaging to detect crossed cerebellar diaschisis (CCD) in patients with their first unilateral supratentorial hyperacute stroke and to identify imaging or clinical factors significantly associated with CCD.

Materials And Methods: We reviewed 204 consecutive patients who underwent MRI less than 8 hours after the onset of stroke symptoms. The inclusion criteria were supratentorial abnormality in diffusion-weighted images in the absence of a cerebellar or brain stem lesion, bilateral supratentorial infarction, subacute or chronic infarction, and MR angiography showing vertebrobasilar system disease. For qualitative analysis, asymmetric cerebellar hypoperfusion in ASL images was categorized into 3 grades. Quantitative analysis was performed to calculate the asymmetric index (AI). The patients' demographic and clinical features and outcomes were recorded. Univariate and multivariate analyses were also performed.

Results: A total of 32 patients met the inclusion criteria, and 24 (75%) presented CCD. Univariate analyses revealed more frequent arterial occlusions, higher diffusion-weighted imaging (DWI) lesion volumes and higher initial NIHSS and mRS scores in the CCD-positive group compared with the CCD-negative group (all p < .05). The presence of arterial occlusion and the initial mRS scores were related with the AI (all p < .05). Multivariate analyses revealed that arterial occlusion and the initial mRS scores were significantly associated with CCD and AI.

Conclusion: ASL imaging could detect CCD in 75% of patients with hyperacute infarction. We found that CCD was more prevalent in patients with arterial occlusion, larger ischemic brain volumes, and higher initial NIHSS and mRS scores. In particular, vessel occlusion and initial mRS score appeared to be significantly related with CCD pathophysiology in the hyperacute stage.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173971PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5360263PMC
August 2017

Identification of cerebral perfusion using arterial spin labeling in patients with seizures in acute settings.

PLoS One 2017 14;12(3):e0173538. Epub 2017 Mar 14.

Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.

This study aimed to explore the utility of arterial spin labeling perfusion-weighted imaging (ASL-PWI) in patients with suspected seizures in acute settings. A total of 164 patients who underwent ASL-PWI for suspected seizures in acute settings (with final diagnoses of seizure [n = 129], poststroke seizure [n = 18], and seizure mimickers [n = 17]), were included in this retrospective study. Perfusion abnormality was analyzed for: (1) pattern, (2) multifocality, and (3) atypical distribution against vascular territories. Perfusion abnormality was detected in 39% (50/129) of the seizure patients, most (94%, 47/50) being the hyperperfusion pattern. Of the patients with perfusion abnormality, multifocality or hemispheric involvement and atypical distribution against vascular territory were revealed in 46% (23/50) and 98% (49/50), respectively. In addition, seizures showed characteristic features including hyperperfusion (with or without non-territorial distribution) on ASL-PWI, thus differentiating them from poststroke seizures or seizure mimickers. In patients in whom seizure focus could be localized on both EEG and ASL-PWI, the concordance rate was 77%. The present study demonstrates that ASL-PWI can provide information regarding cerebral perfusion status in patients with seizures in acute settings and has the potential to be used as a non-invasive imaging tool to identify the cerebral perfusion in patients with seizures.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0173538PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5349669PMC
September 2017

Cerebral blood flow, transit time, and apparent diffusion coefficient in moyamoya disease before and after acetazolamide.

Neuroradiology 2017 Jan 2;59(1):5-12. Epub 2016 Dec 2.

Stanford University Medical Center, Department of Radiology, Neuroradiology Division, Lucas Center, 1201 Welch Rd, Stanford, CA, 94305, USA.

Introduction: The goal of this study was to assess the changes in arterial spin labeling (ASL) cerebral blood flow (CBF) and arterial transit time (ATT), and in apparent diffusion coefficient (ADC), before and after an acetazolamide challenge in moyamoya patients, as function of arterial stenosis severity.

Methods: Pre-operative patients diagnosed with moyamoya disease who could undergo MRI at 3.0T were recruited for this study. A multi-delay pseudo-continuous ASL and a diffusion-weighted sequence were acquired before and 15 min after acetazolamide injection. The severity of anterior, middle, and posterior cerebral artery pathology was graded on time-of-flight MR angiographic images. CBF, ATT, and ADC were measured on standardized regions of interest as function of the vessel stenosis severity.

Results: Thirty patients were included. Fifty-four percent of all vessels were normal, 28% mildly/moderately stenosed, and 18% severely stenosed/occluded. Post-acetazolamide, a significantly larger CBF (ml/100 g/min) increase was observed in territories of normal (+19.6 ± 14.9) compared to mildly/moderately stenosed (+14.2 ± 27.2, p = 0.007), and severely stenosed/occluded arteries (+9.9 ± 24.2, p < 0.0001). ATT was longer in territories of vessel anomalies compared with normal regions at baseline. ATT decreases were observed in all territories post-acetazolamide. ADC did not decrease after acetazolamide in any regions, and no correlation was found between ADC changes and baseline ATT, change in ATT, or CVR.

Conclusion: The hemodynamic response in moyamoya disease, as measured with ASL CBF, is impaired mostly in territories with severe arterial stenosis/occlusion, while ATT was prolonged in all non-normal regions. No significant changes in ADC were observed after acetazolamide.
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http://dx.doi.org/10.1007/s00234-016-1766-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8006793PMC
January 2017

Differentiation of Glioblastoma from Brain Metastasis: Qualitative and Quantitative Analysis Using Arterial Spin Labeling MR Imaging.

PLoS One 2016 18;11(11):e0166662. Epub 2016 Nov 18.

Department of Neurosurgery, Seoul National University Hospital, Seoul, Korea.

Purpose: To evaluate the diagnostic performance of cerebral blood flow (CBF) by using arterial spin labeling (ASL) perfusion magnetic resonance (MR) imaging to differentiate glioblastoma (GBM) from brain metastasis.

Materials And Methods: The institutional review board of our hospital approved this retrospective study. The study population consisted of 128 consecutive patients who underwent surgical resection and were diagnosed as either GBM (n = 89) or brain metastasis (n = 39). All participants underwent preoperative MR imaging including ASL. For qualitative analysis, the tumors were visually graded into five categories based on ASL-CBF maps by two blinded reviewers. For quantitative analysis, the reviewers drew regions of interest (ROIs) on ASL-CBF maps upon the most hyperperfused portion within the tumor and upon peritumoral T2 hyperintensity area. Signal intensities of intratumoral and peritumoral ROIs for each subject were normalized by dividing the values by those of contralateral normal gray matter (nCBFintratumoral and nCBFperitumoral, respectively). Visual grading scales and quantitative parameters between GBM and brain metastasis were compared. In addition, the area under the receiver-operating characteristic curve was used to evaluate the diagnostic performance of ASL-driven CBF to differentiate GBM from brain metastasis.

Results: For qualitative analysis, GBM group showed significantly higher grade compared to metastasis group (p = 0.001). For quantitative analysis, both nCBFintratumoral and nCBFperitumoral in GBM were significantly higher than those in metastasis (both p < 0.001). The areas under the curve were 0.677, 0.714, and 0.835 for visual grading, nCBFintratumoral, and nCBFperitumoral, respectively (all p < 0.001).

Conclusion: ASL perfusion MR imaging can aid in the differentiation of GBM from brain metastasis.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0166662PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5115760PMC
June 2017

MR Imaging Analysis of Non-Measurable Enhancing Lesions Newly Appearing after Concomitant Chemoradiotherapy in Glioblastoma Patients for Prognosis Prediction.

PLoS One 2016 11;11(11):e0166096. Epub 2016 Nov 11.

Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.

Purpose: To analyze the enhancement patterns and apparent diffusion coefficient (ADC) values of non-measurable surgical cavity wall enhancement pattern, newly appearing after completion of standard concurrent chemoradiotherapy (CCRT) with temozolomide in glioblastoma patients for the prognosis prediction.

Materials And Methods: From January 2010 to April 2014, among 190 patients with histopathologically confirmed glioblastoma, a total of 33 patients with non-measurable wall enhancement on post-CCRT MR imaging were enrolled and divided into two subgroups: non-progression (n = 18) and progression groups (n = 15). We analyzed the wall enhancement patterns, which were categorized into three patterns: thin, thick and nodular enhancement. ADC values were measured in the enhancing portions of the walls. The progression-free survival (PFS) related to the wall enhancement was analyzed by Kaplan-Meier analysis, and survival curves were compared using the log-rank test.

Results: Statistically significant differences in the surgical cavity wall enhancement patterns was shown between the progression and non-progression groups (P = 0.0032). Thin wall enhancement was more frequently observed in the non-progression group, and thick or nodular wall enhancement were observed in the progression group (P = 0.0016). There was no statistically significant difference in the mean ADC values between the progression and non-progression groups. The mean PFS was longer in patients with thin wall enhancement than in those with nodular or thick wall enhancement (35.5 months vs. 15.8 months, P = 0.008).

Conclusion: Pattern analysis of non-measurable surgical cavity wall enhancement on post-CCRT MR imaging might be useful tool for predicting prognosis of GBM patient before clear progression of non-measurable disease.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0166096PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5105956PMC
July 2017
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