Hyo Keun Lim

Sungkyunkwan University, Sŏul, Seoul, South Korea

Are you Hyo Keun Lim?

Claim your profile

Publications (106)216.56 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the natural course of subcentimeter hypervascular nodules at high risk for developing into hepatocellular carcinomas (SHNHR) using serial magnetic resonance imaging (MRI) in patients with a history of hepatocellular carcinoma (HCC). An SHNHR was defined as a subcentimeter hypervascular nodule having typical imaging findings of HCC on gadoxetic acid-enhanced MRI and diffusion-weighted imaging. We included 39 patients with 46 SHNHRs (mean size ± standard deviation, 6.1 ± 1.6 mm; range, 3.2 - 9.0 mm). Overt HCC was defined as pathology proven HCC or a nodule larger than 1 cm with typical imaging findings of HCC. The cumulative rate and the independent predictive factors for progression to overt HCC were evaluated. The median follow-up period was 139 days (range, 64 - 392 days). The cumulative progression rate to overt HCC at 3, 6, 9, and 12 months was 13.9 %, 61.7 %, 83.2 %, and 89.9 %. The initial size of SHNHR was a significant predictor of progression to overt HCC, with an optimal cut-off value of 5.5 mm. The progression rate of SHNHR to overt HCC within 12 months was high (89.9 %) in patients with history of HCC. The initial size of SHNHR was an important predictor for progression to overt HCC. • Most SHNHRs (89.9 %) progressed to overt HCCs within 12 months. • Initial size was an important predictor for progression to overt HCCs. • The optimal cut-off value for initial nodule size was 5.5 mm.
    European Radiology 03/2015; DOI:10.1007/s00330-015-3680-9 · 4.34 Impact Factor
  • [Show abstract] [Hide abstract]
    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. (©) RSNA, 2015.
    Radiology 02/2015; DOI:10.1148/radiol.15141215 · 6.21 Impact Factor
  • [Show abstract] [Hide abstract]
    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. (©) RSNA, 2015.
    Radiology 02/2015; DOI:10.1148/radiol.15141483 · 6.21 Impact Factor
  • [Show abstract] [Hide abstract]
    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 radiofrequency ablation for recurrent HCC hepatocellular carcinoma (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 radiofrequency ablation group matching was done by using propensity score matching. The overall survival ( OS overall survival ) and disease-free survival ( DFS disease-free survival ) were compared before and after propensity score matching. Complications were assessed. Results Before matching, OS overall survival 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 radiofrequency ablation. DFS disease-free survival 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 radiofrequency ablation. After matching, the OS overall survival rates at 1, 3, 5, and 8 years were 98.7%, 85.7%, 72.1%, and 68.6%, respectively, and the DFS disease-free survival rates at 1, 3, and 5 years were 71.8%, 45.1%, and 39.4% in the RF radiofrequency ablation group (n = 78). Neither the OS overall survival nor DFS disease-free survival 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 radiofrequency ablation group. Conclusion The long-term OS overall survival and DFS disease-free survival were not significantly different between repeated hepatic resection and RF radiofrequency ablation for patients with recurrent HCC hepatocellular carcinoma after hepatic resection. © RSNA, 2015.
    Radiology 01/2015; DOI:10.1148/radiol.14141568 · 6.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    Investigative Radiology 10/2014; 50(2). DOI:10.1097/RLI.0000000000000103 · 4.45 Impact Factor
  • [Show abstract] [Hide abstract]
    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.
    Baillière&#x027 s Best Practice and Research in Clinical Gastroenterology 10/2014; 28(5). DOI:10.1016/j.bpg.2014.08.011 · 3.28 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to evaluate the enhancement of the efficacy of systemic doxorubicin by pulsed high-intensity focused ultrasound (HIFU)-induced, localized mild hyperthermia. For the in vitro study, the intranuclear uptake of doxorubicin by squamous cell carcinoma (SCC)-7 cells incubated at different temperatures was compared. For the in vivo study, mice with SCC-7 tumors were assigned to either the control, conventional hyperthermia, HIFU hyperthermia, doxorubicin-alone, conventional hyperthermia + doxorubicin or HIFU hyperthermia + doxorubicin group. Conventional hyperthermia was induced by immersing the tumor in warm water (42.5°C), and HIFU hyperthermia was induced by HIFU after optimizing the parameters with direct temperature measurements (frequency = 1 MHz, pulse repetition frequency = 5 Hz, power = 12 W, duty cycle = 50%). In the in vitro study, fluorescence was more intense at 42°C than at 37°C and was time dependent. In the in vivo study, tumor growth in the HIFU hyperthermia + doxorubicin group was most prominently suppressed with the highest apoptotic index compared with all other groups (p < 0.05). Pulsed HIFU-induced localized mild hyperthermia enhanced the anti-cancer efficacy of systemic doxorubicin more than conventional mild hyperthermia.
    Ultrasound in medicine & biology 07/2014; 40(7). DOI:10.1016/j.ultrasmedbio.2014.01.005 · 2.10 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose To determine whether semiquantitative perfusion magnetic resonance (MR) imaging parameters are associated with therapeutic effectiveness of MR imaging-guided high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and which semiquantitative perfusion parameters are significant with regard to treatment efficiency. Materials and Methods This study was approved by the institutional review board, and informed consent was obtained from all subjects. Seventy-seven women (mean age, 43.3 years) with 119 fibroids (mean diameter, 7.5 cm) treated with MR imaging-guided HIFU ablation were analyzed. The correlation between semiquantitative perfusion MR parameters (peak enhancement, relative peak enhancement, time to peak, wash-in rate, washout rate) and heating and ablation efficiencies (lethal thermal dose volume based on MR thermometry and nonperfused volume based on immediate contrast-enhanced image divided by intended treatment volume) were evaluated by using a linear mixed model on a per-fibroid basis. The specific value of the significant parameter that had a substantial effect on treatment efficiency was determined. Results The mean peak enhancement, relative peak enhancement, time to peak, wash-in rate, and washout rate of the fibroids were 1293.1 ± 472.8 (range, 570.2-2477.8), 171.4% ± 57.2 (range, 0.6%-370.2%), 137.2 seconds ± 119.8 (range, 20.0-300.0 seconds), 79.5 per second ± 48.2 (range, 12.5-236.7 per second), and 11.4 per second ± 10.1 (range, 0-39.3 per second), respectively. Relative peak enhancement was found to be independently significant for both heating and ablation efficiencies (B = -0.002, P < .001 and B = -0.003, P = .050, respectively). The washout rate was significantly associated with ablation efficiency (B = -0.018, P = .043). Both efficiencies showed the most abrupt transitions at 220% of relative peak enhancement. Conclusion Relative peak enhancement at semiquantitative perfusion MR imaging was significantly associated with treatment efficiency of MR imaging-guided HIFU ablation of uterine fibroids, and a value of 220% or less is suggested as a screening guideline for more efficient treatment. © RSNA, 2014 Online supplemental material is available for this article.
    Radiology 07/2014; DOI:10.1148/radiol.14132719 · 6.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE. The purposes of this study were to assess the widths of the intercostal spaces of the right inferior human rib cage through which high-intensity focused ultrasound therapy would be applied for treating liver cancer and to elucidate the demographic factors associated with intercostal space width. SUBJECTS AND METHODS. From March 2013 to June 2013, the widths of the intercostal spaces and the ribs at six areas of the right inferior rib cage (area 1, lowest intercostal space on anterior axillary line and the adjacent upper rib; area 2, second-lowest intercostal space on anterior axillary line and the adjacent upper rib; areas 3 and 4, lowest and second-lowest spaces on midaxillary line; areas 5 and 6, lowest and second-lowest spaces on posterior axillary line) were sonographically measured in 466 patients (214 men, 252 women; mean age, 53.0 years) after an abdominal sonographic examination. Demographic factors and the presence or absence of chronic liver disease were evaluated by multivariate analysis to investigate which factors influence intercostal width. RESULTS. The width of the intercostal space was 19.7 ± 3.7 mm (range, 9-33 mm) at area 1, 18.3 ± 3.4 mm (range, 9-33 mm) at area 2, 17.4 ± 4.0 mm (range, 7-33 mm) at area 3, 15.4 ± 3.5 mm (range, 5-26 mm) at area 4, 17.2 ± 3.7 mm (range, 7-28 mm) at area 5, and 14.5 ± 3.6 mm (range, 4-26 mm) at area 6. The corresponding widths of the ribs were 15.2 ± 2.3 mm (range, 8-22 mm), 14.5 ± 2.3 mm (range, 9-22 mm), 13.2 ± 2.0 mm (range, 9-20), 14.3 ± 2.2 mm (range, 9-20 mm), 15.0 ± 2.2 mm (range, 10-22 mm), and 15.1 ± 2.3 mm (range, 8-21 mm). Only female sex was significantly associated with the narrower intercostal width at areas 1, 2, 3, and 5 (regression coefficient, 1.124-1.885; p = 0.01-0.04). CONCLUSION. There was substantial variation in the widths of the intercostal spaces of the right inferior rib cage such that the anterior and inferior aspects of the intercostal space were relatively wider. Women had significantly narrower intercostal spaces than men.
    American Journal of Roentgenology 07/2014; 203(1):201-8. DOI:10.2214/AJR.13.11744 · 2.74 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To determine the value of fusion imaging with contrast-enhanced ultrasonography (CEUS) and computed tomography (CT)/magnetic resonance (MR) images for percutaneous radiofrequency ablation (RFA) of very-early-stage hepatocellular carcinomas (HCCs) that are inconspicuous on fusion imaging with B-mode ultrasound (US) and CT/MR images. This retrospective study was approved by our institutional review board and the requirement for informed consent was waived. Fusion imaging with CEUS using Sonazoid contrast agent and CT/MR imaging was performed on HCCs (<2 cm) that were inconspicuous on fusion imaging with B-mode US. We evaluated the number of cases that became conspicuous on fusion imaging with CEUS. Percutaneous RFA was performed under the guidance of fusion imaging with CEUS. Technical success and major complication rates were assessed. In total, 30 patients with 30 HCCs (mean, 1.2 cm; range, 0.6-1.7 cm) were included, among which 25 (83.3%) became conspicuous on fusion imaging with CEUS at the time of the planning US and/or RFA procedure. Of those 25 HCCs, RFA was considered feasible for 23 (92.0%), which were thus treated. The technical success and major complication rates were 91.3% (21/23) and 4.3% (1/23), respectively. Fusion imaging with CEUS and CT/MR imaging is highly effective for percutaneous RFA of very-early-stage HCCs inconspicuous on fusion imaging with B-mode US and CT/MR imaging.
    03/2014; 20(1):61-70. DOI:10.3350/cmh.2014.20.1.61
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE. MRI-guided high-intensity focused ultrasound (HIFU) ablation is increasingly adopted for treating symptomatic uterine fibroids. As a noninvasive therapy performed on an outpatient basis, it has been viewed by patients to have distinct advantages over other treatment options. However, its breadth of clinical application is still limited. To address this issue, various techniques have been implemented. CONCLUSION. In this article, we discuss techniques that contribute to widening patient selection for MRI-guided HIFU therapy of uterine fibroids.
    American Journal of Roentgenology 02/2014; 202(2):443-51. DOI:10.2214/AJR.13.10753 · 2.74 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports. Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated. Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology. The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology. However, more work is still needed for the complete standardization of terminology.
    Korean journal of radiology: official journal of the Korean Radiological Society 01/2014; 15(1):95-107. DOI:10.3348/kjr.2014.15.1.95 · 1.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Background. Radiofrequency ablation (RFA) as a curative therapy for hepatocellular carcinoma (HCC) is widely used. The aim of this study was to investigate predisposing factors for HCC recurrence in patients with hepatitis B virus (HBV)-related small HCC after RFA. Methods. A total of 170 patients underwent percutaneous RFA for HBV-related small HCC (≤3 cm in diameter) from January 2008 to December 2010 at Samsung Medical Center. We analyzed the risk factors for recurrence of HCC after RFA. Results. The median follow-up duration was 27.0 months. A total of 89 patients (52%) experienced recurrence after percutaneous RFA. Cumulative recurrence-free rates after RFA at 1-, 3-, and 5 years were 81.3%, 47.2% and 35.7%, respectively. Univariate analysis showed that predisposing factors for HCC recurrence were the multinodularity (hazard ratio (HR) 2.22, p = 0.005), pre-RFA HBV DNA levels ≥2000 IU/mL (HR 1.61, p = 0.025), and Barcelona Clinic Liver Cancer stage A (HR 1.54, p = 0.046). The independent risk factors for recurrence by multivariate analysis were the multinodularity (HR 1.94, p = 0.026) and pre-RFA HBV DNA levels ≥2000 IU/mL (HR 1.57, p = 0.039). Conclusion. Multinodularity and HBV DNA levels were associated with the recurrence of HBV-related small HCC after RFA.
    Scandinavian Journal of Gastroenterology 12/2013; DOI:10.3109/00365521.2013.871745 · 2.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To evaluate the safety and therapeutic efficacy of magnetic resonance (MR) imaging-guided high-intensity focused ultrasound (US) ablation of symptomatic uterine fibroid tumors with an immediate nonperfused volume (NPV) ratio of 80% or more. A total of 79 women with 117 uterine tumors were treated with MR-guided high-intensity focused US ablation. Immediate NPV, complications, and therapeutic efficacy (tumor volume reduction ratio and symptom severity score [SSS] decrease at 3-mo follow-up) were retrospectively assessed. Statistical comparisons of the frequency of complications and therapeutic efficacy were performed between patients with NPV ratios of at least 80% and less than 80%. Technical success was achieved in 93.7% of cases (n = 74) of cases, and the immediate NPV ratio was 62.7% ± 25.5. Twenty-four patients exhibited an NPV ratio of at least 80% (89.7% ± 5.8), and 50 patients showed an NPV ratio of less than 80% (49.8% ± 20.7). All complications were minor in severity, and the incidences were not significantly different between groups (P > .05). The 3-month volume reduction ratio was significantly greater in patients with an NPV ratio of at least 80% (0.43 ± 0.17) than in those with an NPV ratio of less than 80% (0.20 ± 0.26; P = .002), although the decreases in SSS were not significantly different (20.9 ± 19.6 vs 12.1 ± 10.1; P = .097). In MR-guided high-intensity focused US ablation of symptomatic uterine fibroid tumors, achievement of an immediate NPV ratio of at least 80% is safe, with greater tumor volume shrinkage compared with cases with a lower NPV ratio.
    Journal of vascular and interventional radiology: JVIR 12/2013; 25(2). DOI:10.1016/j.jvir.2013.11.011 · 2.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE/AIM The aim of the this exhibit is 1. To describe the imaging features and managements of various complications associated with radiofrequency ablation (RFA) 2. To review the risk factors potentially affecting RFA-induced complications 3. To determine the impact of RFA-induced complications on the long term outcomes of RFA. CONTENT ORGANIZATION Although RFA is considered to be a safe and effective technique for treating liver tumors, various complications can happen when inadequately performed. We have performed more than 6,000 RFA procedures for treating liver tumors during the recent 14 years period and encountered diverse procedure-related complications. We divided RFA-induced complications into five types: hemorrhage, hepatic vascular injuries, biliary injuries, extrahepatic organ injuries and tumor progression. SUMMARY The major teaching points of this exhibit are 1. Because an early and accurate diagnosis of complications is mandatory for proper management, radiologists should be familiar with the imaging features, as well as management strategies of RFA-induced complication. 2. Through understanding of risk factors for developing RFA-induced complications may be beneficial in preventing potential complications. 3. Physicians who perform RFA should be aware of the impact of RFA-induced complications on the long term therapeutic outcomes of RFA.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE To investigate whether it is feasible to estimate the change of hepatic venous pressure gradient (HVPG) using Supersonic shear wave elastography (SWE) in the patients with portal hypertension. METHOD AND MATERIALS Twenty-three consecutive patients who were diagnosed with portal hypertension (>=6 mmHg of HVPG) on initial HVPG measurement and who underwent follow-up measurement to evaluate response to treatment were enrolled in this retrospective study. Liver stiffness measurement was performed in all of the subjects, followed by HVPG measurement through transjugular catheterization on the same day. Liver stiffness was obtained intercostally, which was repeated 5 times at the same location of the right liver. The relationship between the HVPG and liver stiffness on initial measurement and on follow-up was investigated by using Pearson’s correlation test. Furthermore, we evaluated whether a change in the HVPG (ΔHVPG) was correlated with a change in the liver stiffness (ΔLS). The subjects were subdivided into two groups: those in whom the HVPG at follow-up decreased by >=20% compared to the initial measurement (clinical improvement), and those in whom the percentage of decrease was less than 20%. The performance to determine improvement of portal hypertension was investigated using the receiver operating characteristics (ROC) curve analysis. RESULTS Liver stiffness was significantly correlated with HVPG at initial and follow-up measurements (r=0.501 and 0.527, respectively). The mean rate and difference of ΔLS were strongly correlated with ΔHVPG (r=0.863 and 0.707, respectively). To determine the improvement of portal hypertension, the area under the ROC curve was 0.79 of rate of ΔLS, and 0.78 of difference of ΔLS. CONCLUSION Supersonic SWE is feasible method to determine improvement of portal hypertension in cirrhotic patients. CLINICAL RELEVANCE/APPLICATION Supersonic SWE is available for evaluation of improvement of portal hypertension,;therefore ;can replace;conventional invasive;catheterization.Supersonic SWE is available for evaluation of improvement
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatocyte specific contrast agents including gadoxetic acid and gadobenate dimeglumine are very useful to diagnose various benign and malignant focal hepatic lesions and even helpful to estimate hepatic functional reservoir. The far delayed phase image referred to as the hepatobiliary phase makes the sensitivity of detection for malignant focal hepatic lesions increased, but specificity of malignant diseases, including hepatocellular carcinoma, metastasis and cholangiocarcinoma, characterization remained to be undetermined.
    12/2013; 19(4):360-366. DOI:10.3350/cmh.2013.19.4.360
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose To compare the long-term therapeutic outcomes of radiofrequency (RF) ablation for small perivascular hepatocellular carcinoma (HCC) and nonperivascular HCC. Materials and Methods This retrospective study was approved by the institutional review board. Between December 2004 and April 2008, 241 patients (175 men and 66 women; age range, 32-82 years) with a single early-stage HCC that was 3 cm or smaller in the greatest dimension underwent ultrasonography-guided percutaneous RF ablation as a first-line treatment. The patients were divided into two groups according to the presence or absence of contacting hepatic vessels that were 3 mm or larger in axial diameter: a group with perivascular HCC (n = 58) and a group with nonperivascular HCC (n = 183). Cumulative local tumor progression, disease-free and long-term survival rates, and prognostic factors were assessed by using Cox proportional hazard models with Bonferroni correction. Results The overall median follow-up period was 58 months (range, 13-92 months). The cumulative local tumor progression rates were 10%, 16%, and 26% at 1, 3, and 5 years, respectively, in the perivascular group, and 6.7%, 15.5%, and 20.5% in the nonperivascular group; the differences were not significant (P = .323). The corresponding disease-free survival rates were 79%, 41%, and 29% in the perivascular group and 71.3%, 38.7%, and 26.0% in the nonperivascular group, with no significant difference (P = .689). The corresponding overall survival rates were 100%, 94%, and 82% in the perivascular group and 100%, 88.4%, and 73.9% in the nonperivascular group, also without significant difference (P = .267). There was no significant prognostic factor for local tumor progression, whereas extrahepatic and intrahepatic distant recurrences were significant prognostic factors for overall survival in multivariable analysis. Conclusion The long-term therapeutic outcomes of RF ablation as first-line treatment for small perivascular HCC were similar to those for nonperivascular HCC. © RSNA, 2013.
    Radiology 11/2013; 270(3):130753. DOI:10.1148/radiol.13130753 · 6.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVE. In MRI-guided high-intensity focused ultrasound ablation of uterine fibroids, bowel interposition in the sonication path is often problematic. The purpose of this article is to discuss a bowel-manipulation technique to displace the bowel loop, which consisted of sequential applications of urinary bladder filling, rectal filling, and urinary bladder emptying. CONCLUSION. This technique contributed to a decreased screening failure rate and succeeded in consistently displacing the bowel loop, thus allowing safe treatment of fibroids in the anteverted or anteflexed uterus.
    American Journal of Roentgenology 11/2013; 201(5):W761-4. DOI:10.2214/AJR.12.10081 · 2.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose:To determine whether intraprocedural thermal parameters as measured with magnetic resonance (MR) thermometry can be used to predict immediate or delayed therapeutic response after MR-guided high-intensity focused ultrasound (HIFU) ablation of uterine fibroids.Materials and Methods:Institutional review board approval and subject informed consent were obtained. A total of 105 symptomatic uterine fibroids (mean diameter, 8.0 cm; mean volume, 251.8 mL) in 71 women (mean age, 43.3 years; age range, 25-52 years) who underwent volumetric MR HIFU ablation were analyzed. Correlations between tumor-averaged intraprocedural thermal parameters (peak temperature, thermal dose efficiency [estimated volume of 240 equivalent minutes at 43°C divided by volume of treatment cells], and temperature decay rate after sonication) and the immediate ablation efficiency (ratio of nonperfused volume [NPV] at immediate follow-up to treatment cell volume) or ablation sustainability (ratio of NPV at 3-month follow-up to NPV at immediate follow-up) were assessed with linear regression analysis.Results:A total of 2818 therapeutic sonications were analyzed. At immediate follow-up with MR imaging (n = 105), mean NPV-to-fibroid volume ratio and ablation efficiency were 0.68 ± 0.26 (standard deviation) and 1.35 ± 0.75, respectively. A greater thermal dose efficiency (B = 1.894, P < .001) and slower temperature decay rate (B = -1.589, P = .044) were independently significant factors that indicated better immediate ablation efficiency. At 3-month follow-up (n = 81), NPV had decreased to 43.1% ± 21.0 of the original volume, and only slower temperature decay rate was significantly associated with better ablation sustainability (B = -0.826, P = .041).Conclusion:The postsonication temperature decay rate enables prediction of both immediate and delayed therapeutic responses, whereas thermal dose efficiency enables prediction of immediate therapeutic response to MR HIFU ablation of uterine fibroids.© RSNA, 2013.
    Radiology 09/2013; 270(2). DOI:10.1148/radiol.13130380 · 6.21 Impact Factor

Publication Stats

1k Citations
216.56 Total Impact Points

Institutions

  • 2002–2015
    • Sungkyunkwan University
      • • Samsung Medical Center
      • • School of Medicine
      • • Department of Radiology
      Sŏul, Seoul, South Korea
  • 2012
    • University of Seoul
      Sŏul, Seoul, South Korea
  • 2000–2012
    • Samsung Medical Center
      • Department of Radiology
      Sŏul, Seoul, South Korea