• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.721-728
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• 2019

The purpose of this study was to evaluate the relationship between bone mineral density (BMD) and body composition (BC) or backmuscle strength (BS). Sixty-one participants were measured by BMD using ultrasound bone densitometry and Inbody for BC (i.e., SLM=Soft lean mass, SMM=Skeletal muscle mass, FS=Fitness score. et al.), BS after self-questionnaire for life cycle. This study was performed after approving Institutional Review Board and obtaining the informed concent from all participants. Participants was divided into two group by BMD T-score; $T-score{\geq}-1.0$, T-score<-1.0. Statistical analysis was performed by using SPSS ver. 22.0(USA), Spearma test for correlation between BMD and BC or BS. BMD or SLM, BS was increased with increasing physical activity or body mass index. SMM or SMM, FS of BMD $T-score{\geq}-1.0$ group was higher than that of T-score <-1.0 group as well as BS(p>0.05). BMD T-score was correlated positively with SLM(r= 0.424) or SMM(r= 0.431) in men, as well as in women(p<0.05). BS was correlated positively with SLM or SMM, FS. BS was significantly positive correlated with BMD in women group (r= 0.591, p= 0.001), but not in men group. We concluded that BMD is the relationship with SLM or SMM, as well as BS in women.

• Journal of the Korean Society of Radiology
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• v.17 no.3
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• pp.393-399
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• 2023

The purpose of this study was to evaluate the effect on school records of family environment, learner's attitude, school life, seat position in college students. The questionnaire surveyed for family environment, learner's attitude, school life by 121 students, and conformed the school records after consent and institutional review board. Mean age was 21.7-year, and men 54.5% and women 45.5% for sex. Learner's attitude and school life are significantly positively correlated for school records(p<0.001), and school life satisfaction and learner's attitude are significantly positively correlated for family environment(p<0.001). It showed significantly correlation between school life and learner's attitude(r=0.437, p<0.001). Seat position is significantly higher in men more than women(3.40 vs. 3.89, p=0.004), as well as in grader. Between school records ≥ 90% and <90% group showed statistically difference in school life (4.35 vs. 4.11, p=0.045) or learner's attitude(3.75 vs. 3.37, p=0.004), seat position(3.89 vs. 3.45, p=0.007). Therefor, school records are effected significantly by learner's attitude and school life, seat position in college students.

• Korean Journal of Radiology
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• v.21 no.9
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• pp.1077-1086
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• 2020

Objective: To evaluate the effect of perfluorobutane microbubbles (Sonazoid^®, GE Healthcare) on steam popping during radiofrequency (RF) ablation for treating hepatocellular carcinoma (HCC), and to assess whether popping affects treatment outcomes. Materials and Methods: The institutional review board approved this retrospective study, which included 90 consecutive patients with single HCC, who received percutaneous RF ablation as the first-line treatment. The patients were divided into two groups, based on the presence or absence of the popping phenomenon, which was defined as an audible sound with a simultaneous sudden explosion within the ablation zone as detected via ultrasonography during the procedure. The factors contributing to the popping phenomenon were identified using multivariable logistic regression analysis. Local tumor progression (LTP) and disease-free survival (DFS) were assessed using the Kaplan-Meier method with the log-rank test for performing comparisons between the two groups. Results: The overall incidence of the popping phenomenon was 25.8% (24/93). Sonazoid^® was used in 1 patient (4.2%) in the popping group (n = 24), while it was used in 15 patients (21.7%) in the non-popping group (n = 69). Multivariable analysis revealed that the use of Sonazoid^® was the only significant factor for absence of the popping phenomenon (odds ratio = 0.10, p = 0.048). There were no significant differences in cumulative LTP and DFS between the two groups (p = 0.479 and p = 0.424, respectively). Conclusion: The use of Sonazoid^® has a suppressive effect on the popping phenomenon during RF ablation in patients with HCC. However, the presence of the popping phenomenon may not affect clinical outcomes.

• Korean Journal of Radiology
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• v.23 no.8
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• pp.828-834
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• 2022

Objective: This study aimed to assess the outcomes of outpatient day-care management of unruptured intracranial aneurysm (UIA), and to present the risks associated with different management strategies by comparing the outcomes and adverse events between outpatient day-care management and management with longer admission periods. Materials and Methods: This retrospective cohort study used prospectively registered data and was approved by a local institutional review board. We enrolled 956 UIAs from 811 consecutive patients (mean age ± standard deviation, 57 ± 10.7 years; male:female = 247:564) from 2017 to 2020. We compared the outcomes after embolization among the different admission-length groups (1, 2, and ≥ 3 days). The outcomes included pre- and post-modified Rankin Scale (mRS) scores and rates of adverse events, cure, recurrence, and reprocedure. Events were defined as any cerebrovascular problems, including minor and major stroke, death, or hemorrhage. Results: The mean admission period was 2 days, and 175 patients (191 aneurysms), 551 patients (664 aneurysms), and 85 patients (101 aneurysms) were discharged on the day of the procedure, day 2, and day 3 or later, respectively. During the mean 17-month follow-up period (range 6-53 months; 2757 patient years), no change in post-mRS was observed compared to pre-mRS in 99.6% of patients. Cure was achieved in 95.6% patients; minimal recurrence that did not require re-procedure occurred in 3.5% patients, and re-procedure was required in 2.3% (22 of 956) patients due to progressive enlargement of the recurrent sac during follow up (mean 17 months, range, 6-53 months). There were eight adverse events (0.8%), including five cerebrovascular (two major stroke, two minor strokes and one transient ischemic stroke), and three non-cerebrovascular events. Statistical comparison between groups with different admission lengths (1, 2, and ≥ 3 days) revealed no difference in the outcomes. Conclusion: This study revealed no difference in outcomes and adverse events according to the admission period, and suggested that UIA could be managed by outpatient day-care embolization.

• Korean Journal of Radiology
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• v.22 no.5
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• pp.770-781
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• 2021

Objective: Chemical exchange-dependent saturation transfer (CEST) MRI is sensitive for detecting solid-like proteins and may detect changes in the levels of mobile proteins and peptides in tissues. The objective of this study was to evaluate the characteristics of chemical exchange proton pools using the CEST MRI technique in patients with dementia. Materials and Methods: Our institutional review board approved this cross-sectional prospective study and informed consent was obtained from all participants. This study included 41 subjects (19 with dementia and 22 without dementia). Complete CEST data of the brain were obtained using a three-dimensional gradient and spin-echo sequence to map CEST indices, such as amide, amine, hydroxyl, and magnetization transfer ratio asymmetry (MTR_asym) values, using six-pool Lorentzian fitting. Statistical analyses of CEST indices were performed to evaluate group comparisons, their correlations with gray matter volume (GMV) and Mini-Mental State Examination (MMSE) scores, and receiver operating characteristic (ROC) curves. Results: Amine signals (0.029 for non-dementia, 0.046 for dementia, p = 0.011 at hippocampus) and MTR_asym values at 3 ppm (0.748 for non-dementia, 1.138 for dementia, p = 0.022 at hippocampus), and 3.5 ppm (0.463 for non-dementia, 0.875 for dementia, p = 0.029 at hippocampus) were significantly higher in the dementia group than in the non-dementia group. Most CEST indices were not significantly correlated with GMV; however, except amide, most indices were significantly correlated with the MMSE scores. The classification power of most CEST indices was lower than that of GMV but adding one of the CEST indices in GMV improved the classification between the subject groups. The largest improvement was seen in the MTR_asym values at 2 ppm in the anterior cingulate (area under the ROC curve = 0.981), with a sensitivity of 100 and a specificity of 90.91. Conclusion: CEST MRI potentially allows noninvasive image alterations in the Alzheimer's disease brain without injecting isotopes for monitoring different disease states and may provide a new imaging biomarker in the future.

• Korean Journal of Radiology
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• v.22 no.2
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• pp.179-188
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• 2021

Objective: This study aimed to prospectively compare the efficacy, safety, and mid-term outcomes of dual-switching monopolar (DSM) radiofrequency ablation (RFA) to those of conventional single-switching monopolar (SSM) RFA in the treatment of hepatocellular carcinoma (HCC). Materials and Methods: This single-center, two-arm, parallel-group, randomized controlled study was approved by the Institutional Review Board. Written informed consent was obtained from all patients upon enrollment. A total of 80 patients with 94 HCC nodules were randomized into either the DSM-RFA group or SSM-RFA group in a 1:1 ratio, using a blocked randomization method (block size 2). The primary endpoint was the minimum diameter of the ablation zone per unit time. The secondary endpoints included other technical parameters, complication rate, technique efficacy, and 2-year clinical outcomes. Results: Significantly higher ablation energy per unit time was delivered to the DSM-RFA group than to the SSM-RFA group (1.7 ± 0.2 kcal/min vs. 1.2 ± 0.3 kcal/min; p < 0.001). However, no significant differences were observed between the two groups for the analyzed variables, including primary endpoint, regarding size of the ablation zone and ablation time. Major complication rates were 4.9% in the DSM-RFA group and 2.6% in the SSM-RFA group (p = 1.000). The 2-year local tumor progression (LTP) rates of the HCC nodules treated using DSM-RFA and SSM-RFA were 8.5% and 4.7%, respectively (p = 0.316). The 2-year LTP-free survival rates of patients in the DSM-RFA and SSM-RFA groups were 90.0% and 94.4%, respectively (p = 0.331), and the 2-year recurrence-free survival rates were 54.9% and 75.7%, respectively (p = 0.265). Conclusion: Although DSM-RFA using a separable clustered electrode delivers higher ablation energy than SSM-RFA, its effectiveness failed to show superiority over SSM-RFA in the treatment of HCC.

• Korean Journal of Radiology
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• v.20 no.5
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• pp.812-822
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• 2019

Objective: To assess the diagnostic value of combining diffusion-weighted imaging (DWI) with conventional magnetic resonance imaging (MRI) for differentiating between pathologic and traumatic fractures at extremities from metastasis. Materials and Methods: Institutional Review Board approved this retrospective study and informed consent was waived. This study included 49 patients each with pathologic and traumatic fractures at extremities. The patients underwent conventional MRI combined with DWI. For qualitative analysis, two radiologists (R1 and R2) independently reviewed three imaging sets with a crossover design using a 5-point scale and a 3-scale confidence level: DWI plus non-enhanced MRI (NEMR; DW set), NEMR plus contrast-enhanced fat-saturated T1-weighted imaging (CEFST1; CE set), and DWI plus NEMR plus CEFST1 (combined set). McNemar's test was used to compare the diagnostic performances among three sets and perform subgroup analyses (single vs. multiple bone abnormality, absence/presence of extra-osseous mass, and bone enhancement at fracture margin). Results: Compared to the CE set, the combined set showed improved diagnostic accuracy (R1, 84.7 vs. 95.9%; R2, 91.8 vs. 95.9%, p < 0.05) and specificity (R1, 71.4% vs. 93.9%, p < 0.005; R2, 85.7% vs. 98%, p = 0.07), with no difference in sensitivities (p > 0.05). In cases of absent extra-osseous soft tissue mass and present fracture site enhancement, the combined set showed improved accuracy (R1, 82.9-84.4% vs. 95.6-96.3%, p < 0.05; R2, 90.2-91.1% vs. 95.1-95.6%, p < 0.05) and specificity (R1, 68.3-72.9% vs. 92.7-95.8%, p < 0.005; R2, 83.0-85.4% vs. 97.6-98.0%, p = 0.07). Conclusion: Combining DWI with conventional MRI improved the diagnostic accuracy and specificity while retaining sensitivity for differentiating between pathologic and traumatic fractures from metastasis at extremities.

• Korean Journal of Radiology
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• v.20 no.8
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• pp.1275-1284
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• 2019

Objective: To develop algorithms using convolutional neural networks (CNNs) for automatic segmentation of acute ischemic lesions on diffusion-weighted imaging (DWI) and compare them with conventional algorithms, including a thresholding-based segmentation. Materials and Methods: Between September 2005 and August 2015, 429 patients presenting with acute cerebral ischemia (training:validation:test set = 246:89:94) were retrospectively enrolled in this study, which was performed under Institutional Review Board approval. Ground truth segmentations for acute ischemic lesions on DWI were manually drawn under the consensus of two expert radiologists. CNN algorithms were developed using two-dimensional U-Net with squeeze-and-excitation blocks (U-Net) and a DenseNet with squeeze-and-excitation blocks (DenseNet) with squeeze-and-excitation operations for automatic segmentation of acute ischemic lesions on DWI. The CNN algorithms were compared with conventional algorithms based on DWI and the apparent diffusion coefficient (ADC) signal intensity. The performances of the algorithms were assessed using the Dice index with 5-fold cross-validation. The Dice indices were analyzed according to infarct volumes (< 10 mL, ≥ 10 mL), number of infarcts (≤ 5, 6-10, ≥ 11), and b-value of 1000 (b1000) signal intensities (< 50, 50-100, > 100), time intervals to DWI, and DWI protocols. Results: The CNN algorithms were significantly superior to conventional algorithms (p < 0.001). Dice indices for the CNN algorithms were 0.85 for U-Net and DenseNet and 0.86 for an ensemble of U-Net and DenseNet, while the indices were 0.58 for ADC-b1000 and b1000-ADC and 0.52 for the commercial ADC algorithm. The Dice indices for small and large lesions, respectively, were 0.81 and 0.88 with U-Net, 0.80 and 0.88 with DenseNet, and 0.82 and 0.89 with the ensemble of U-Net and DenseNet. The CNN algorithms showed significant differences in Dice indices according to infarct volumes (p < 0.001). Conclusion: The CNN algorithm for automatic segmentation of acute ischemic lesions on DWI achieved Dice indices greater than or equal to 0.85 and showed superior performance to conventional algorithms.

• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.40-46
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• 2012

Purpose : To investigate the feasibility of in vivo proton magnetic resonance spectroscopy (MRS) for evaluation of lung cancer. Materials and Methods: This prospective study was approved by the institutional review board of our hospital and informed consent was obtained in all patients. Ten patients (7 men, 3 women; mean age, 64.4) with pathologicallyproven lung cancer (mean, 56.8 mm; range, 44-77 mm) were enrolled to 1.5 T MRS using a single-voxel respiration-triggered point-resolved spectroscopic sequence. Technical success rate and the reason of technical failure, if any, were investigated. Results: Out of 10 lung cancers, analyzable MRS spectra were obtained in 8 tumors (technical success rate, 80%). Two MRS datasets were not able to be analyzed due to serious baseline distortion. Choline and lipid signals were detected as major metabolites in analyzable MRS spectra. Conclusion: In vivo proton MRS method using a single-voxel respiration-triggered point-resolved spectroscopic sequence is feasible in obtaining the MR spectra of lung cancer because these spectra were analyzable and high success rate was shown in our study although there was the limitation of small patient group.

• Imaging Science in Dentistry
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• v.43 no.2
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• pp.91-98
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• 2013

Purpose: This study was performed to identify correlations between keratocystic odontogenic tumor (KCOT) data from CT sections, and data on the KCOT clinical manifestation and resulting dental expenses. Materials and Methods: Following local Institutional Review Board (IRB) approval, a seven-years of retrospective study was performed regarding patients with KCOTs treated at the Seoul National University Dental Hospital. A total of 180 KCOT were included in this study. The following information was collected: age, gender, location and size of the lesion, radiological features, surgical treatment provided and dental expenses. Results: There was no significant association between the size of the KCOT and age, gender, and presenting preoperative symptoms. In both jaws, it was unusual to find KCOTs under 10 mm. The correlation between the number of teeth removed and the size of the KCOT in the tooth bearing area was statistically significant in the mandible, whereas in the maxilla, no significant relationship was found. Dental expenses compared with the size of the KCOT were found to be significant in both jaws. Conclusion: The size of KCOT was associated with a significant increase in dental expenses for both jaws and the number of teeth removed from the mandible. These findings emphasize the importance of routine examinations and early detection of lesions, which in turn helps preserving anatomical structures and reducing dental expenses.