Min Woo Lee

Hallym University, Sŏul, Seoul, South Korea

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Publications (198)484.24 Total impact

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    ABSTRACT: Background & aims: To investigate the differences in mechanical effects and ablation zone between radiofrequency (RF) ablation with and without Sonazoid uptake in an in vivo rabbit liver model. Methods: Our study was approved by the Institutional Animal Care and Use Committee. Twenty-five rabbits were randomly allotted to one of five ablation durations (i.e., 1, 2, 3, 6, and 12 min). For each rabbit, RF ablation was performed twice, before and 10 min after Sonazoid administration (i.e. control group vs. Sonazoid group) using a 1-cm internally-cooled electrode (40W) equipped with a parallelly-fixed pressure-monitoring device. During ablation, a "popping" sound was perceived and recorded along with tissue pressure changes and RF ablation parameters. Then, the ablation volume and microscopic changes were compared. Results: Popping sounds were more frequently perceived in the control group (21/25 vs. 1/25, P<0.001). The time to first pressure peak was shorter in the Sonazoid group (22.3±1.1s vs. 46.3±4.4s, P<0.001) with similar pressures (39.8±4.2 mmHg vs. 35.6±4.1 mmHg, P=0.350). Time to first roll-off and mean power output were significantly less in the Sonazoid group (17.6±1.2s vs. 71.2±8.2s, P<0.001; 9.4±0.3 W vs. 12.8±0.5 W, P<0.001). Consequently, the Sonazoid group had lower total energy and ablation volumes for all durations. Microscopically, the control group showed larger confluent disruptions, whereas the Sonazoid group showed many smaller disruptions scattered throughout the ablation zones. Conclusions: RF ablation after Sonazoid uptake induces a smaller ablation zone than conventional RF ablation. However, it appears to ablate the liver tissue with less mechanical effects. This article is protected by copyright. All rights reserved.
    No preview · Article · Feb 2016 · Liver international: official journal of the International Association for the Study of the Liver
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    ABSTRACT: Purpose To compare the long-term therapeutic outcomes of radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) in subcapsular versus nonsubcapsular locations by using propensity score matching. Materials and Methods RF ablation for subcapsular HCC is controversial because of a high risk of incomplete ablation or major complications. This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. Between April 2006 and December 2011, 508 consecutive patients (396 men, 112 women; age range, 30-80 years) with a single HCC (Barcelona Clinic Liver Cancer stage 0 or A) underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment. The patients were divided into two groups according to tumor location: subcapsular (n = 227) and nonsubcapsular (n = 281). Subcapsular HCC was defined as an index tumor located within 0.1 cm of the liver capsule. The association of subcapsular location and therapeutic outcomes of RF ablation was evaluated, including (a) local tumor progression (LTP) by using a competing risk regression model and (b) overall survival (OS) by using a Cox proportional hazards model according to propensity score matched data. The major complication rates from both overall data and matched data were assessed. Results Matching yielded 163 matched pairs of patients. In the two matched groups, cumulative LTP rates were 18.8% and 20.9% at 3 and 5 years, respectively, in the subcapsular group and 13.2% and 16.0% in the nonsubcapsular group. Corresponding OS rates were 90.7% for 3 years and 83.2% for 5 years in the subcapsular group and 91.4% and 79.1%, respectively, in the nonsubcapsular group. Hazard ratios (HRs) for LTP (HR = 1.37, P = .244) and OS (HR = 0.86, P = .604) were not significantly different between the two matched groups. Additionally, differences in major complication rates were not significant between groups for the two sets of data (P > .05). Conclusion The differences in LTP, OS, and major complication rates of RF ablation for HCC were not significant between subcapsular and nonsubcapsular groups. (©) RSNA, 2016.
    No preview · Article · Jan 2016 · Radiology
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    ABSTRACT: Aims: Inflammation plays essential role in development of plaque disruption and coronary stent-associated complications. This study aimed to examine whether intracoronary dual-modal optical coherence tomography (OCT)-near-infrared fluorescence (NIRF) structural-molecular imaging with indocyanine green (ICG) can estimate inflammation in swine coronary artery. Methods and results: After administration of clinically approved NIRF-enhancing ICG (2.0 mg/kg) or saline, rapid coronary imaging (20 mm/s pullback speed) using a fully integrated OCT-NIRF catheter was safely performed in 12 atheromatous Yucatan minipigs and in 7 drug-eluting stent (DES)-implanted Yorkshire pigs. Stronger NIRF activity was identified in OCT-proven high-risk plaque compared to normal or saline-injected controls (P = 0.0016), which was validated on ex vivo fluorescence reflectance imaging. In vivo plaque target-to-background ratio (pTBR) was much higher in inflamed lipid-rich plaque compared to fibrous plaque (P < 0.0001). In vivo and ex vivo peak pTBRs correlated significantly (P < 0.0022). In vitro cellular ICG uptake and histological validations corroborated the OCT-NIRF findings in vivo. Indocyanine green colocalization with macrophages and lipids of human plaques was confirmed with autopsy atheroma specimens. Two weeks after DES deployment, OCT-NIRF imaging detected strong NIRF signals along stent struts, which was significantly higher than baseline (P = 0.0156). Histologically, NIRF signals in peri-strut tissue co-localized well with macrophages. Conclusion: The OCT-NIRF imaging with a clinical dose of ICG was feasible to accurately assess plaque inflammation and DES-related inflammation in a beating coronary artery. This highly translatable dual-modal molecular-structural imaging strategy could be relevant for clinical intracoronary estimation of high-risk plaques and DES biology.
    Full-text · Article · Jan 2016 · European Heart Journal
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    ABSTRACT: Objectives: To develop and validate a prediction model using magnetic resonance imaging (MRI) for local tumour progression (LTP) after radiofrequency ablation (RFA) in hepatocellular carcinoma (HCC) patients. Methods: Two hundred and eleven patients who had received RFA as first-line treatment for HCC were retrospectively analyzed. They had undergone gadoxetic acid-enhanced MRI before treatment, and parameters including tumour size; margins; signal intensities on T1-, T2-, and diffusion-weighted images, and hepatobiliary phase images (HBPI); intratumoral fat or tumoral capsules; and peritumoural hypointensity in the HBPI were used to develop a prediction model for LTP after treatment. This model to discriminate low-risk from high-risk LTP groups was constructed based on Cox regression analysis. Results: Our analyses produced the following model: 'risk score = 0.617 × tumour size + 0.965 × tumour margin + 0.867 × peritumoural hypointensity on HBPI'. This was able to predict which patients were at high risk for LTP after RFA (p < 0.001). Patients in the low-risk group had a significantly better 5-year LTP-free survival rate compared to the high-risk group (89.6 % vs. 65.1 %; hazard ratio, 3.60; p < 0.001). Conclusion: A predictive model based on MRI before RFA could robustly identify HCC patients at high risk for LTP after treatment. Key points: • Tumour size, margin, and peritumoural hypointensity on HBPI were risk factors for LTP. • The risk score model can predict which patients are at high risk for LTP. • This prediction model could be helpful for risk stratification of HCC patients.
    No preview · Article · Jan 2016 · European Radiology
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    ABSTRACT: To report the results of combined therapy with transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) for early stage hepatocellular carcinoma (HCC) considered infeasible for ultrasound (US)-guided RFA in comparison with those of TACE monotherapy. From January 2007 through December 2010, 91 patients with early or very early stage HCC infeasible for US-guided RFA received either TACE alone (TACE group; n = 54) or TACE immediately followed by RFA (TACE-RFA group; n = 37) as a first-line treatment. 1-month tumor response, time to progression (TTP), and overall survival (OS) rates were calculated. Univariate and multivariate analyses were performed to identify prognostic factors. TACE-RFA group showed a better 1-month tumor response than TACE group (P < .001). The mean TTP was 29.7 ± 3.4 months (95 % confidence intervals [CIs] 23.0-36.5) in TACE group and 34.9 ± 2.8 months (95 % CIs 29.4-40.4) in TACE-RFA group. TACE-RFA group had a significantly longer TTP (P = .014). Cumulative 1-, 2-, and 3-year OS rates in the TACE and TACE-RFA groups were 91, 79, and 71 % and 100, 97, and 93 %, respectively (P = .008). Initial treatment of TACE was found to be the only significant risk factor for tumor progression and OS in multivariate analysis. TACE-RFA combination therapy appears superior to TACE monotherapy in terms of 1-month tumor response, TTP, and OS when performed for early stage HCC infeasible for US-guided RFA.
    No preview · Article · Aug 2015 · CardioVascular and Interventional Radiology
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    ABSTRACT: We experimented with different ablation methods and two types of microwave antennas to determine whether microwave ablation (MWA) increases intrahepatic pressure and to identify an MWA protocol that avoids increasing intrahepatic pressure. MWA was performed using either a single-step standard ablation or a stepwise increment ablation paired with either a 16-gauge (G) 2-cm antenna or a 14G 4-cm antenna. We compared the maximum pressures and total ablation volumes. The mean maximum intrahepatic pressures and ablation volumes were as follows 16G single-step 37±33.4 mm Hg and 4.63 cm(3); 16G multistep 31±18.7 mm Hg and 3.75 cm(3); 14G single-step 114±45.4 mm Hg and 15.33 cm(3); and 14G multistep 106±43.8 mm Hg and 10.98 cm(3). The intrahepatic pressure rose during MWA, but there were no statistically significant differences between the single and multistep methods when the same gauge antennae were used. The total ablation volume was different only in the 14G groups (p<0.05). We demonstrated an increase in intrahepatic pressure during MWA. The multistep method may be used to prevent increased intrahepatic pressure after applying the proper power.
    Full-text · Article · May 2015 · Gut and Liver
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    ABSTRACT: The guideline for the management of hepatocellular carcinoma (HCC) was first developed in 2003 and revised in 2009 by the Korean Liver Cancer Study Group and the National Cancer Center, Korea. Since then, many studies on HCC have been carried out in Korea and other countries. In particular, a substantial body of knowledge has been accumulated on diagnosis, staging, and treatment specific to Asian characteristics, especially Koreans, prompting the proposal of new strategies. Accordingly, the new guideline presented herein was developed on the basis of recent evidence and expert opinions. The primary targets of this guideline are patients with suspicious or newly diagnosed HCC. This guideline provides recommendations for the initial treatment of patients with newly diagnosed HCC.
    Full-text · Article · May 2015 · Korean Journal of Radiology
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    ABSTRACT: Regional differences in nerve resting membrane potential have been associated with susceptibility to entrapment neuropathy. The aim of this study was to test whether the different susceptibilities to carpal tunnel syndrome (CTS) of median nerve motor axons supplying the second lumbrical (L2) and abductor pollicis brevis (APB) muscles could be explained in this way. Computerized nerve-excitability testing was used to examine the excitability properties of the median motor axons of both L2 and APB in 24 healthy volunteers. Although some excitability measurements differed between the L2 and APB motor axons, estimates of resting membrane potential (RMP) by model fitting indicated no significant difference between the two groups. Differences in RMP cannot account for the relative sparing of L2 axons in severe CTS. L2 sparing in CTS most likely has an anatomical rather than a biophysical basis. Copyright © 2015. Published by Elsevier Ireland Ltd.
    No preview · Article · May 2015 · Clinical Neurophysiology
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    ABSTRACT: To compare the performance of the 15-gauge (G) internally cooled electrode with that of the conventional 17-G internally cooled electrode. A total of 40 (20 for each electrode) and 20 ablation zones (ten for each electrode) were made in extracted bovine livers and in in vivo porcine livers, respectively. Technical parameters, three dimensions [long- (Dl), vertical- (Dv), and short-axis diameter (Ds)], volume, and the circularity (Ds/Dl) of ablation zone were compared. Total delivered energy was higher in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (8.78 ± 1.06 kcal vs 7.70 ± 0.98 kcal, p = 0.033; 11.20 ± 1.13 kcal vs 8.49 ± 0.35 kcal, p = 0.001; respectively). The three dimensions of ablation zone had a tendency to be larger in the 15-G group than in the 17-G group in both studies. The ablation volume was larger in the 15-G group than in the 17-G group in both ex vivo and in vivo studies (29.61 ± 7.10 cm(3) vs 23.86 ± 3.82 cm(3), p = 0.015; 10.26 ± 2.28 cm(3) vs 7.79 ± 1.68 cm(3), p = 0.028; respectively). The circularity of ablation zone was not significantly different in both studies. The size of ablation zone was larger in the 15-G internally cooled electrode than in the 17-G electrode in both ex vivo and in vivo studies. Advances in Knowledge: Radiofrequency ablation of hepatic tumours using 15-G electrode is useful to create larger ablation zone.
    No preview · Article · Apr 2015 · The British journal of radiology
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    ABSTRACT: Tandem architecture between organic (dye-sensitized solar cell, DSSC) and inorganic (CuInGaSe2 thin film solar cell, CIGS) single-junction solar cells was constructed particularly based on a solution process. Arc-plasma deposition was employed for the Pt interfacial layer to minimize the damage to the layers of the CIGS bottom cell. Solar cell efficiency of 13% was achieved, which is significant progress from individual single-junction solar cells (e.g., 7.25 and 6.2% for DSSC and CIGS, respectively).
    Full-text · Article · Mar 2015 · Scientific Reports
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    ABSTRACT: Purpose: To evaluate the frequency, risk factors, and clinical significance of aggressive intrasegmental recurrence (AIR) found after radiofrequency (RF) ablation for hepatocellular carcinoma (HCC). Materials and methods: Institutional review board approval was obtained for this retrospective study. Between March 2005 and December 2010, 539 patients (414 men, 125 women; mean age, 57.91 years; age range, 30-82 years) underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment for a single HCC classified as Barcelona Clinic Liver Cancer (BCLC) stage 0 or A. AIR of HCC was defined as (a) initial tumor recurrence with disease-free status at least 6 months after initial RF ablation and (b) the simultaneous development of multiple nodular (at least three) or infiltrative tumor recurrence in the treated segment. Patients were stratified into two groups: those with AIR (n = 20) and those without AIR (n = 519) during follow-up. Risk factors for AIR were assessed with logistic regression analysis, and risk factors for long-term overall survival were assessed with time-dependent Cox proportional hazard models. Results: In a median follow-up period of 49 months (range, 6-95 months), AIR was observed in 3.7% of the patients (20 of 539 patients), with the frequency increasing to 15% in the subgroup with periportal HCC (11 of 72 patients). AIRs manifested as either multiple nodular type (n = 14, BCLC stage A or B) or diffusely infiltrative type with tumor thrombus formation (n = 6, BCLC stage C). At multivariate analysis, periportal tumor location and younger patient age were significant risk factors for AIR. The presence of AIR during the follow-up period has a significant effect on the overall survival rate (hazard ratio = 5.72, P = .002). Conclusion: The overall frequency of AIR after RF ablation for HCC was low, with periportal location and patient age showing a significant relationship to the development of AIR. The occurrence of AIR had an adverse effect on overall survival rate.
    No preview · Article · Feb 2015 · Radiology
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    ABSTRACT: Purpose: To compare radiofrequency (RF) ablation with nonanatomic resection (NAR) as first-line treatment in patients with a single Barcelona Clinic Liver Cancer (BCLC) stage 0 or A hepatocellular carcinoma (HCC) and to evaluate the long-term outcomes of both therapies. Materials and methods: This retrospective study was approved by the institutional review board. The requirement for informed consent was waived. Data were reviewed from 580 patients with HCCs measuring 3 cm or smaller (BCLC stage 0 or A) who underwent ultrasonographically (US) guided percutaneous RF ablation (n = 438) or NAR (n = 142) as a first-line treatment. Local tumor progression, intrahepatic distant recurrence, disease-free survival, and overall survival rates were analyzed by using propensity score matching to compare therapeutic efficacy. In addition, major complications and length of postoperative hospital stay were compared. Results: Before propensity score matching (n = 580), the 5-year cumulative rates of local tumor progression for RF ablation and NAR (20.9% vs 12.7%, respectively; P = .093) and overall survival rates (85.5% vs 90.9%, respectively; P = .194) were comparable, while the 5-year cumulative intrahepatic distant recurrence rates (62.7% vs 36.6%, respectively; P < .001) and disease-free survival rates (31.7% vs 61.1%, respectively; P < .001) in the NAR group were significantly better than those in the RF ablation group. After matching (n = 198), there were no significant differences in therapeutic outcomes between the RF ablation and NAR groups, including 5-year cumulative intrahepatic distant recurrence (47.0% vs 40.2%, respectively; P = .240) and disease-free survival rates (48.9% vs 54.4%, respectively; P = .201). RF ablation was superior to NAR for major complication rates and length of postoperative hospital stay (P < .001). Conclusion: In patients with one BCLC stage 0 or A (≤ 3 cm) HCC who received RF ablation or NAR as first-line treatment, there were no significant differences in long-term therapeutic outcomes; however, RF ablation was associated with fewer major complications and a shorter hospital stay after treatment.
    No preview · Article · Feb 2015 · Radiology
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    ABSTRACT: The objectives of this study were to explore the feasibility of applying sequential dilute acid and alkali pretreatment into the hydrolysis of corn stover and to elucidate the effects of structural changes in the biomass on its enzymatic digestibility. H2SO4 used in the first step selectively hydrolyzed 74.6-77.3% of xylan and NaOH used in the second step removed 85.9-89.4% of lignin, from the raw corn stover. Compared to single dilute acid pretreatment, the proposed combined pretreatment minimized the generation of byproducts such as acetic acid, furfural and hydroxymethylfurfural in the hydrolysates, and enhanced the enzymatic hydrolysis of the solid residue. The changes in the structural features (porosity, morphology, and crystallinity) of the solid residue were strongly correlated with the enhancement of enzymatic digestibility. The overall glucose and xylose yields finally obtained after enzymatic hydrolysis reached 89.1-97.9% and 71.0-75.9%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Full-text · Article · Feb 2015 · Bioresource Technology
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    ABSTRACT: Purpose: To compare the long-term outcomes of repeated hepatic resection and radiofrequency (RF) ablation for recurrent hepatocellular carcinoma (HCC) by using propensity score matching. Materials and methods: This retrospective study was approved by the institutional review board, and the requirement to obtain informed consent was waived. Thirty-nine patients who underwent repeated hepatic resection and 178 who underwent RF ablation for recurrent HCC (mean tumor size ± standard deviation, 1.8 cm ± 0.7) between November 1994 and December 2012 were included in the study. Patients ranged in age from 24 to 85 years (mean, 54.9 years). Men ranged in age from 25 to 85 years (mean, 54.8 years), and women ranged in age from 24 to 76 years (mean, 55.4 years). A 1:2 repeated hepatic resection group-RF ablation group matching was done by using propensity score matching. The overall survival (OS) and disease-free survival (DFS) were compared before and after propensity score matching. Complications were assessed. Results: Before matching, OS rates at 1, 3, 5, and 8 years were 88.8%, 88.8%, 83.9%, and 56.3%, respectively, with repeated hepatic resection and 98.9%, 82.5%, 71.0%, and 58.3% for RF ablation. DFS rates at 1, 3, and 5 years were 66.1%, 48.5%, and 43.1% for repeated hepatic resection and 70.1%, 40.8%, and 30.0% for RF ablation. After matching, the OS rates at 1, 3, 5, and 8 years were 98.7%, 85.7%, 72.1%, and 68.6%, respectively, and the DFS rates at 1, 3, and 5 years were 71.8%, 45.1%, and 39.4% in the RF ablation group (n = 78). Neither the OS nor DFS rate was significantly different between the two groups before matching (P = .686 and P = .461) and after matching (P = .834 and P = .960). The postoperative mortality rate was 2.6% in the repeated hepatic resection group and 0% in the RF ablation group. Conclusion: The long-term OS and DFS were not significantly different between repeated hepatic resection and RF ablation for patients with recurrent HCC after hepatic resection.
    No preview · Article · Jan 2015 · Radiology
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    Yung Bum Seo · Min Woo Lee · Young Ho Lee · Jae Kwon Jung
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    ABSTRACT: In-situ CaCO3 formation on recycled wood pulp was studied to improve optical property and filler attachment to the fiber furnish in papermaking. We tried to attach calcium oxide (CaO) to the recycled fibers, old newspaper (ONP) in this case, by using selected polymers before in-situ CaCO3 formation reaction on fibers, and then, CO2 was injected to the furnish until all the CaO on fiber surfaces was consumed. It was found that the attachment of newly formed CaCO3 to recycled fibers became stronger by attaching CaO to the fibers before in-situ CaCO3 formation reaction. It was expected that the polymers used for the attachment of calcium source to the fiber furnishes helped to keep the newly formed CaCO3 strongly attached to the fiber surface as well as to retain the impurities associated with calcium source and recycled fibers, if any. In-situ CaCO3 formation gave higher brightness and much less ERIC value in ONP sheet than the case when the equivalent amount of GCC was added to the furnish.
    Full-text · Article · Oct 2014 · Palpu Chongi Gisul/Journal of Korea Technical Association of the Pulp and Paper Industry
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    Min Woo Lee · Young Ho Lee · Jae Kwon Jung · Yung Bum Seo
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    ABSTRACT: In-situ CaCO3 formation onto recycled wood pulp was studied to improve optical properties and ash attachment to the fiber furnish in papermaking. We controlled initial reaction temperature of in-situ CaCO3 formation method from 30°C to 50°C. It was found that the attachment of newly formed CaCO3 to recycled fibers, old newspaper (ONP) in this case, was stronger than that of ground calcium carbonate (GCC, mean dia. 2.4 μm) addition case, but was not much different among those formed at different temperature. Morphologies of newly formed CaCO3 were changed according to the reaction temperature. More aragonite shape was seen at higher temperature. In-situ CaCO3 formation increased brightness and lowered ERIC value of ONP sheet greatly at the same level of ash contents when compared to GCC addition method, but gave equivalent ERIC and brightness when compared to those of the precipitated calcium carbonate (PCC) addition method. However, tensile strength of the handsheets of the in-situ CaCO3 formation method were much greater than those of the PCC addition method.
    Full-text · Article · Oct 2014 · Palpu Chongi Gisul/Journal of Korea Technical Association of the Pulp and Paper Industry
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    ABSTRACT: Objectives: The objective of this study was to compare the targeting and ablation performance between a newly developed radiofrequency (RF) electrode embedded with an electromagnetic position sensor (EMPS) at the electrode tip and a conventional RF electrode. Materials and methods: The institutional animal care and use committee approved this study. The targeting of paint balls within phantoms was performed under ultrasonography guidance by 2 radiologists (beginner vs expert) with an "in-plane" and "out-of-plane" approaches using the new RF electrode and a conventional RF electrode (n = 20 for each method). To evaluate the targeting performance, the electrode placement time and the number of electrode pullbacks for redirection were compared between the 2 electrodes. The ablation performance was also compared by analyzing the ablation volumes in ex vivo bovine and in vivo porcine livers (n = 30 and n = 24, respectively) and the cellular viability of the ablation zone in in vivo specimens. Results: In the phantom study, the RF electrode embedded with an EMPS showed a significantly shorter electrode placement time compared with the conventional RF electrode in both the in-plane and out-of-plane approaches by both radiologists (P < 0.05). The electrode pullback rate for both radiologists was lower in the new RF electrode than in the conventional RF electrode, but it did not reach statistical significance in the in-plane approach by the expert (P = 0.059). The ablation volumes analyzed with and without cellular viability in the ex vivo and in vivo studies were not significantly different between the 2 electrodes (P > 0.05). Conclusions: The RF electrode embedded with an EMPS is faster than the conventional electrode in the electrode placement into the target lesions. The ablation performance is not significantly different between the 2 electrodes.
    No preview · Article · Oct 2014 · Investigative Radiology
  • Jun Young Kim · Min Woo Lee · Hongki Yoo
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    ABSTRACT: Fiber optics miniaturization and advances in signal acquisition and processing have allowed the development of fiber-based optical imaging catheters that permit instantaneous luminal organ imaging. This technique is applicable in clinical settings for diagnosing various diseases. Intravascular optical coherence tomography (IV-OCT), a catheter-based optical imaging technique, acquires high-resolution cross-sectional human coronary arterial wall imaging, enabling precise assessment of coronary atherosclerosis. OCT with a ballooncentering catheter or a tethered capsule acquires comprehensive three-dimensional images of the distal esophagus for diagnostic imaging in patients with esophageal diseases, including Barrett’s esophagus. Spectrally encoded confocal microscopy (SECM), an advanced type of confocal microscopy that uses diffraction grating and a broadband laser source to laterally scan the sample without mechanical motion, has been developed as a tethered confocal endomicroscopy capsule to diagnose and monitor eosinophilic esophagitis, an allergic condition in the esophageal wall. In this review, the authors describe the recent development of fiber-based imaging catheters with rotary scanning for diagnosing various diseases in luminal organs, including the coronary artery and esophagus. Further developments, including miniaturization of optics, increased speed, and multimodal acquisition, could significantly improve diagnostic capability to improve patient care. © 2014, Korean Society of Medical and Biological Engineering and Springer.
    No preview · Article · Oct 2014 · Biomedical Engineering Letters
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    ABSTRACT: Radiofrequency ablation (RFA) has gained a wide acceptance as a first-line therapeutic option for small hepatocellular carcinoma (HCC). For very early-stage HCC, despite a higher rate of local tumor progression, RFA is considered as a viable alternative to surgical resection owing to its comparable long-term survival, reduced morbidity, and greater preservation of hepatic parenchyma. For HCCs larger than 2cm, RFA can contribute to near-curative therapy when combined with chemoembolization. RFA can be used as part of a multimodal treatment strategy for more advanced or recurrent cases, and could be a useful bridging therapy for patients who are waiting for liver transplantation. However, the use of RFA is still limited in treating large tumors and some tumors in high-risk locations. To overcome its current limitations, other ablation techniques are being developed and it is important to validate the role of other techniques for enhancing performance of ablation therapy for HCC.
    No preview · Article · Oct 2014 · Baillière&#x027 s Best Practice and Research in Clinical Gastroenterology
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    ABSTRACT: Objective: The objective of our study was to evaluate the added value of diffusion-weighted imaging (DWI) for distinguishing between malignant and benign focal splenic lesions. Materials and methods: This study included 53 patients with 11 malignant and 42 benign splenic lesions who underwent gadoxetic acid-enhanced MRI and DWI. Qualitative and quantitative analyses were conducted for splenic lesions. Two blinded observers evaluated the two image sets--that is, the conventional MR images alone versus the combined conventional MR and DW images--and scored their confidence for malignancy of splenic lesions. The Fisher exact test and Mann-Whitney U test were performed, and diagnostic performance values (ROC curve analysis) were evaluated. Results: All malignant lesions showed a progressive hypovascular enhancement pattern, whereas the hypervascular enhancement patterns were shown in only benign lesions (n = 20, 47.6%) (p < 0.05). The mean apparent diffusion coefficient (ADC) of the malignant lesions (0.73 × 10(-3) mm(2)/s) was significantly lower than that of the benign lesions (1.21 × 10(-3) mm(2)/s) (p < 0.001). The addition of DW images to conventional MR images showed a significant improvement for predicting malignant splenic lesions (area under ROC curve [Az] without DW images vs with DW images: 0.774 vs 0.983 for observer 1 and 0.742 vs 0.986 for observer 2) (p < 0.001). In addition, the diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of combined conventional MR and DW images were higher than those of conventional MR images alone. Conclusion: The addition of DWI to conventional MRI improves differentiation of malignant from benign splenic lesions.
    Preview · Article · Oct 2014 · American Journal of Roentgenology

Publication Stats

2k Citations
484.24 Total Impact Points

Institutions

  • 2012-2015
    • Hallym University
      • College of Medicine
      Sŏul, Seoul, South Korea
    • University of Seoul
      Sŏul, Seoul, South Korea
  • 2011-2015
    • Keimyung University
      • Department of Chemical Engineering
      Sŏul, Seoul, South Korea
    • Hanbat National University
      • Department of Chemical and Biological Engineering
      Daiden, Daejeon, South Korea
  • 2009-2015
    • Samsung Medical Center
      • Department of Radiology
      Sŏul, Seoul, South Korea
    • Sungkyunkwan University
      • • Samsung Medical Center
      • • Department of Molecular and Cell Biology
      Sŏul, Seoul, South Korea
  • 2007-2015
    • Korea Institute of Science and Technology
      • • Clean Energy Research Center
      • • Photo-electronic Hybrids Research Center
      • • Doping Control Center
      Sŏul, Seoul, South Korea
  • 2014
    • Korea University
      • Department of Biomedical Science
      Sŏul, Seoul, South Korea
    • Hanyang University
      • Department of Biomedical Engineering
      Sŏul, Seoul, South Korea
  • 2006-2014
    • University of Chicago
      • Department of Molecular Genetics & Cell Biology
      Chicago, Illinois, United States
  • 2013
    • Sejong University
      Sŏul, Seoul, South Korea
  • 2010-2013
    • Chungnam National University
      • Department of Bio Based Materials
      Daiden, Daejeon, South Korea
    • Fairchild Semiconductor
      San José, California, United States
  • 2006-2010
    • Konkuk University
      • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2005-2010
    • Inha University
      • Department of Information and Communication Engineering
      Chemulpo, Incheon, South Korea
  • 1998-2009
    • Pohang University of Science and Technology
      • • Department of Chemical Engineering
      • • School of Environmental Science and Engineering
      Antō, North Gyeongsang, South Korea
  • 2008
    • Korea Institute of Energy Research
      Sŏul, Seoul, South Korea
    • Amkor Technology
      Chandler, Arizona, United States
  • 2007-2008
    • Konkuk University Medical Center
      • Department of Radiology
      Changnyeong, South Gyeongsang, South Korea
  • 2002-2008
    • Seoul National University Hospital
      • Department of Radiology
      Sŏul, Seoul, South Korea
  • 1999
    • Henry Ford Hospital
      Detroit, Michigan, United States