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Hyunchul Rhim

Publications and source records attributed to Hyunchul Rhim.

At least 19 recordsLinked to original sources
PubMed2006

Hemobilia after radiofrequency ablation of hepatocellular carcinoma.

OBJECTIVE: The purpose of this study was to report on the clinical course and imaging findings of hemobilia after radiofrequency (RF) ablation in four patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: From July 2000 to December 2005, we experienced four cases of hemobilia after 1574 sessions of ultrasonography (US)-guided RF ablation in 1037 patients with HCCs. All ablation procedures were percutaneously performed with an internally cooled RF electrode system. The diagnosis of hemobilia was made if the patient complained of melena after RF ablation and biliary dilatation with high attenuating bile was noted at CT obtained immediately after RF ablation. We evaluated the clinical course and imaging findings of hemobilia caused by RF ablation. RESULTS: All patient well tolerated RF ablation procedures without any incident during the procedure. Three of four patients complained of melena with an interval from 1 day to 4 days after RF ablation. One patient was asymptomatic. The melena symptom in all symptomatic patients spontaneously improved in 2 days. None of the patients showed substantial change in vital sign and the level of hemoglobin during the admission period. In all four patients, biliary (including GB) dilatation with high attenuating bile was noted at immediate follow-up CT. The CT findings in all four patients disappeared at 1 month follow-up CT. CONCLUSION: Hemobilia is a rare potential complication of RF ablation with a favorable prognosis. Clinicians who use this technique should be aware of the characteristic CT findings and clinical course of hemobilia after RF ablation for liver tumors.

Aged↗
PubMed2006

Percutaneous radiofrequency ablation for early-stage hepatocellular carcinoma as a first-line treatment: long-term results and prognostic factors in a large single-institution series.

The purpose of this study was to evaluate the long-term survival results and complications of percutaneous radiofrequency ablation (RFA) in patients with early-stage hepatocellular carcinoma (HCC). Between April 1999 and May 2005, 570 patients with 674 early-stage HCCs underwent percutaneous RFA as a first-line treatment option in a single institution. We evaluated the effectiveness rates, local tumor progression rates, survival rates, and complications. We also assessed the prognostic values of survival rates by using Cox proportional hazard models. The primary technique effectiveness rate was 96.7% (652 of 674). The cumulative rates of local tumor progression at 1, 2, and 3 years were 8.1%, 10.9%, and 11.8%, respectively. The cumulative survival rates at 1, 2, 3, 4, and 5 years were 95.2%, 82.9%, 69.5%, 60.8%, and 58.0%, respectively. Patients with Child-Pugh class A cirrhosis, of younger age (<or=58 years), or having lower AFP level (<or=100 microg/L) demonstrated better survival results (P < 0.05). A total of 11 major complications (1.9% per treatment) were found during the follow-up period. There was no procedure-related death. Percutaneous RFA can be used successfully as a first-line treatment modality for early-stage HCCs. Child-Pugh class, age, and AFP level before RFA were significant prognostic predictors of long-term survival.

Adult↗
PubMed2006

Computed tomographic differentiation between alcoholic and gallstone pancreatitis: Significance of distribution of infiltration or fluid collection.

AIM: To evaluate the usefulness of various computed tomography (CT) findings including distribution of infiltration or fluid collection in differentiating the major etiologies of acute pancreatitis. METHODS: We reviewed 75 relatively severe cases of acute pancreatitis of alcoholic (n = 43) or biliary stone (n = 32) etiology having infiltration or fluid collection on CT. We compared the pancreatic size, CT grading, presence or absence of biliary calculi, and dilatation of pancreatic or bile duct. We also evaluated degree and the distribution of infiltration and fluid collection in each group. RESULTS: The sizes of pancreas were not different between alcohol group and stone group. Alcohol group showed higher CT grading than stone group (P < 0.05). Presence of biliary stone and duct dilatation was statistically significant in differentiating etiology (P < 0.05). Alcohol group showed significantly prominent peripancreatic pathology than stone group only in left peritoneal compartment (P = 0.020). CONCLUSION: Alcoholic pancreatitis tends to form more prominent peripancreatic changes than gallstone pancreatitis in relatively severe cases. This is evident on the anterior aspect of left abdomen. Although clinical history and some CT findings usually are a major determinant of the etiology, this pattern of peripancreatic pathology may have an ancillary role in determining the etiologies of acute pancreatitis in the equivocal cases.

Acute Disease↗
PubMed2006

Intrahepatic recurrence after percutaneous radiofrequency ablation of hepatocellular carcinoma: analysis of the pattern and risk factors.

PURPOSE: To evaluate the pattern and risks for intrahepatic recurrence after percutaneous radiofrequency (RF) ablation for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: We studied 62 patients with 72 HCCs (< or =4 cm) who were treated with percutaneous RF ablation. The mean follow-up period was 19.1 months (6.0-49.1). We assessed the incidence and cumulative disease-free survival of local tumor progression (LTP) and intrahepatic distant recurrence (IDR). To analyze the risk factors, we examined the following, for the LTP: (1) tumor diameter, (2) contact with vessels, (3) degree of approximation to hepatic hilum, (4) contact with hepatic capsule, (5) presence of ablative safety margin, (6) degree of benign periablational enhancement and (7) serum alpha-fetoprotein; for the IDR: (1) severity of hepatic disease, (2) presence of HBsAg, (3) serum alpha-fetoprotein, (4) whether RF ablation was the initial treatment and (5) multiplicity of tumor for IDR. RESULTS: The incidence of overall recurrence, LTP and IDR was 62.9%, 26.4% and 53.2%, respectively. The cumulative disease-free survival rates were 52%, 82% and 56% at 1 year, 26%, 63% and 30% at 2 years, respectively. Univariate analysis showed that the significant risk factors for LTP were: a tumor with a diameter >3 cm, contact of HCC with a vessel and an insufficient safety margin (p<0.05). A multivariate stepwise Cox hazard model showed that the measurement of a tumor diameter >3 cm and insufficient safety margin were independent factors. Only the increased serum alpha-fetoprotein was a significant risk factor for IDR (p<0.05). CONCLUSION: Intrahepatic recurrence after percutaneous RF ablation is common. Large HCC (>3 cm) with high serum alpha-fetoprotein should be treated more aggressively because of higher risk for recurrence.

Adult↗
PubMed2006

Radiofrequency ablation of benign cold thyroid nodules: initial clinical experience.

CONTEXT AND OBJECTIVE: To evaluate the efficacy and safety of ultrasound (US)-guided percutaneous radiofrequency (RF) ablation for benign cold thyroid nodules as a nonsurgical therapeutic modality. DESIGN, INTERVENTION, AND PATIENTS: A total of 35 benign cold thyroid nodules in 30 euthyroid patients (M:F = 2:28; mean age 39.1 years) underwent percutaneous RF ablation with a 1-cm-internally cooled electrode. Seventy-seven percent (23/30) of patients required conscious sedation for discomfort. We evaluated the tumor size, cystic component, vascularity (by color Doppler US), and the severity of mass-related symptoms before treatment. We assessed the therapeutic efficacy and safety of RF ablation by clinical and US follow-up (median 6.4 months). MAIN OUTCOME AND RESULTS: The volume of the tumors before ablation had a range of 0.6-28.2 mL (mean, 6.3 mL). The residual volume was 53.5% +/- 26.5% of original at 1.1-2.9 months (n = 32), 36.2% +/- 27.4% at 3.0-5.9 months (n = 20), 30.7% +/- 25.0% at 6.0-8.9 months (n = 15), and 11.8% +/- 10.9% at 9.0-18.5 months (n = 13). Mixed/mainly cystic tumors showed a significantly better response than mainly solid tumors (p < 0.05). Difference in vascularity did not affect the treatment response. Thyroid function after the procedure was maintained as normal in all patients. Eighty-eight percent of the patients reported an improvement of their symptoms. There was no major complication other than vocal cord palsy in one patient (3.3%). CONCLUSION: RF ablation may be an effective and safe nonsurgical technique to treat benign cold thyroid nodules.

Adolescent↗
PubMed2006

Radiofrequency ablation of the liver in a rabbit model: creation of artificial ascites to minimize collateral thermal injury to the diaphragm and stomach.

PURPOSE: To assess whether the creation of artificial ascites during radiofrequency (RF) ablation of the subcapsular portion of the liver can minimize collateral thermal injury to the diaphragm and stomach. MATERIALS AND METHODS: A total of 20 percutaneous RF ablation procedures were performed in the livers of 10 rabbits (control, n = 5; experimental, n = 5) with use of an internally cooled electrode (1-cm active tip). In the experimental group, artificial ascites was established before RF ablation by dripping 320 mL of normal saline solution via a 20-gauge sheathed needle to separate the liver from the diaphragm and stomach. In each rabbit, two subcapsular ablation zones were made in the inferior tip of the left lobe of the liver adjacent to the stomach and in the far dome of the right lobe next to the diaphragm consecutively. After the animals were killed 3 days after the procedure, the frequency, size, and degree of thermal injury were compared between the experimental and control groups. The degree of thermal injury was graded by visual inspection according to a four-point scoring system. Representative cases underwent gross and histologic analysis. RESULTS: Artificial ascites was achieved successfully with a single puncture in all rabbits in the experimental group. Mean procedure time for the formation of artificial ascites was 9 minutes. There was no difference in the size of the RF ablation zones in the liver between the two groups (P > .05). Thermal injury in the adjacent organs was observed significantly more frequently in the control group compared with the experimental group (diaphragm, 100% vs 0; stomach, 80% vs 20%; P < .05). CONCLUSION: Creation of artificial ascites may be a simple and useful technique that can be used to reduce the frequency and severity of thermal injury during RF ablation of subcapsular hepatic tumors.

Animals↗
PubMed2006

Percutaneous radiofrequency ablation therapy of hepatocellular carcinoma using multitined expandable electrodes: comparison of subcapsular and nonsubcapsular tumors.

OBJECTIVE: Our objective was to compare the prognosis of subcapsular and nonsubcapsular hepatocellular carcinoma after percutaneous radiofrequency ablation using multitined expandable electrodes. MATERIALS AND METHODS: Some controversies exist about the clinical usefulness of percutaneous radiofrequency ablation of subcapsular hepatocellular carcinoma. Twenty-eight patients underwent percutaneous radiofrequency ablation of 43 hepatocellular carcinomas using multitined expandable electrodes. Twelve tumors were subcapsular and 31 were nonsubcapsular. We attempted to use normal liver as a pathway to the tumor when possible. Tumor size ranged from 1.0 to 4.2 cm (mean, 1.8 cm). Median follow-up was 16 months. Initial ablation was considered to have been complete when no enhancement was seen in the region of the ablated lesion on 1-month follow-up CT or on follow-up CT performed immediately after repeated ablation. Initial complete ablation and local tumor progression rates were compared between subcapsular and nonsubcapsular tumors. Eleven patients had subcapsular tumors (group 1), whereas the other 17 patients did not have subcapsular tumors (group 2). Major complication and mortality rates were compared between the two groups. RESULTS: No significant differences in initial complete ablation rate (100% vs 96.7%, p = 1.000) or local tumor progression rate (0% vs 10.0%, p = 0.545) were found between subcapsular and nonsubcapsular tumors. No procedure-related major complication or mortality occurred. The overall 1- and 3-year survival rates were 89.3% and 60.3%, respectively. CONCLUSION: The rates of local tumor progression and complications for radiofrequency ablation using multitined expandable electrodes for subcapsular hepatocellular carcinomas were comparable to those for nonsubcapsular hepatocellular carcinomas.

Aged↗
PubMed2006

Percutaneous radiofrequency ablation of hepatocellular carcinoma: effect of histologic grade on therapeutic results.

OBJECTIVE: The purpose of our study was to assess the therapeutic results of radiofrequency ablation of hepatocellular carcinoma (HCC) based on the histologic grades of the tumors. SUBJECTS AND METHODS: Between April 1999 and December 2003, 95 patients with nodular HCC were treated with percutaneous radiofrequency ablation. All tumors were histologically proven by sonography-guided percutaneous biopsy and were classified as Edmondson-Steiner grade I HCC (n = 38) (mean, 2.3 cm) (group 1), grade II HCC (n = 50) (mean, 2.4 cm) (group 2), or grade III HCC (n = 7) (mean, 2.8 cm) (group 3). All patients underwent contrast-enhanced three-phase helical CT examination before and after radiofrequency ablation. After retrospective review of the medical records and follow-up CT examinations, the rates of technique effectiveness, local tumor progression, cumulative survival, and cancer-free survival using a Kaplan-Meier method were calculated and compared among the groups. RESULTS: Technique effectiveness rates in groups 1, 2, and 3 were 87% (27/31), 71% (30/42), and 43% (3/7), respectively, with statistical significance (p = 0.032). Local tumor progression rates in groups 1, 2, and 3 were 16% (5/31), 36% (15/42), and 71% (5/7), respectively, with statistical significance (p = 0.013). Five-year cumulative survival rates in groups 1, 2, and 3 were 71%, 44%, and 43%, respectively, with no statistical significance (p > 0.05). Four-year cancer-free survival rates in groups 1, 2, and 3 were 39%, 10%, and 0%, respectively (p < 0.05 for groups 1 vs 2; p > 0.05 for groups 1 vs 3 and groups 2 vs 3). CONCLUSION: The histologic grade of HCC is an important factor influencing therapeutic results with survival after radiofrequency ablation.

Carcinoma, Hepatocellular↗
PubMed2005

Image-guided tumor ablation: standardization of terminology and reporting criteria.

The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency, laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes.

Catheter Ablation↗
PubMed2005

Bronchobiliary fistula after radiofrequency thermal ablation of hepatic tumor.

A broad spectrum of complications can occur after radiofrequency (RF) ablation of hepatic tumors, even though it has been accepted as a safe and effective technique for unresectable hepatic tumors. Recently, the rare complication of brochobiliary fistula was encountered after RF ablation in a patient with a metastatic tumor from stomach cancer. It was assumed to have developed from collateral damage to the adjacent diaphragm and lung base as well as biloma formation at the ablation zone. Symptomatic improvement was achieved by conservative management with an external drainage catheter, but the fistula was still persistent on a 2-month follow-up image.

Adenocarcinoma↗
PubMed2005

Image-guided tumor ablation: standardization of terminology and reporting criteria.

The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency (RF), laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes. The intent of this standardization of terminology is to provide an appropriate vehicle for reporting the various aspects of image-guided ablation therapy.

Catheter Ablation↗
PubMed2004

Dual-probe radiofrequency ablation: an in vitro experimental study in bovine liver.

OBJECTIVE: To determine whether alternative radiofrequency (RF) application with dual probes has advantages over sequential or simultaneous RF application for creating larger coagulation necrosis. MATERIALS AND METHODS: Using 2 17-gauge internally cooled electrodes and a 200-watt generator (CC-3 model, Radionics), RF energy was applied sequentially (group A, n = 20), simultaneously (group B, n = 20), or alternately (group C, n = 20) to explanted bovine liver. After preliminary experiments with a probe distance of 2-5 cm, a distance of 2 cm and 3 cm were chosen for main experiments. Total duration of the RF application was 10 minutes. In the alternative mode, the energy was applied alternately to both RF electrodes in 2-second intervals. Changes occurring in tissue impedance, current, power output, and temperature at the midpoint between the 2 electrodes were measured. The technical parameters, temperatures, and dimension of the ablated area were compared in the 3 groups using analysis of variance or Kruskal-Wallis test. RESULTS: In the groups B and C, the impedance was gradually decreased during RF application and the mean current flow of both groups was 1550 +/- 130 mA and 1375 +/- 175 mA, respectively. However, in the group A, the impedance was markedly increased during RF application, and the mean current was 940 +/- 484 mA (P < 0.05, between groups A and B, and groups A and C). With 3-cm spacing, the alternative RF application created oval-shaped ablation zones with larger shortest axis diameter at the midpoint than either the sequential or simultaneous RF application: 12.0 +/- 7.1 mm in group A; 27.0 +/- 3.1 mm in group B; 34.9 +/- 3.4 mm in group C (P < 0.05). With 2 cm spacing, the corresponding figures were 25.3 +/- 7.8 mm in group A; 34.9 +/- 7.8 mm in group B; 41.5 +/- 1.8 mm in group C (P < 0.05): the differences between groups A and B, and between groups A and C were statistically significant (P < 0.05). With 3-cm spacing, the temperature at the midpoint between the 2 probes was higher in group C (102 degrees C) than in either the group A (62 degrees C) or the group B (78 degrees C; P < 0.05). With 2-cm spacing, groups B and C showed higher temperature than group A (P < 0.05), but the difference between groups B and C was not significant (P > 0.05). CONCLUSION: The alternative RF application creates larger, more regular ablation zones than either the sequential or simultaneous RF application. This result suggests that use of an alternating RF power application will improve the results of RF ablation for the treatment of larger tumors.

Animals↗
PubMed2003

Image-guided tumor ablation: proposal for standardization of terms and reporting criteria.

The field of image-guided tumor ablation requires standardization of terms and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments with different technologies, such as chemical ablation (ethanol or acetic acid) and thermal therapies, such as radiofrequency, laser, microwave, ultrasound, and cryoablation. On the basis of this premise, a working committee was established with the goal of producing a proposal on such standardization. The intent of the Working Group is to provide a framework that will facilitate the clearest communication between investigators and will provide the greatest flexibility in comparisons between the many new, exciting, and emerging technologies. The members of the Working Group now propose a vehicle for reporting the various aspects of image-guided ablation therapy, including classifications of therapies and procedures, appropriate descriptors of image guidance, and terms to define imaging and pathologic findings. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's hope and intention that adherence to the recommendations of this proposal will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and ultimately to improved patient outcomes.

Catheter Ablation↗
PubMed2002

Primary retroperitoneal synovial sarcoma: a case report.

A case of a 36-yr-old woman with retroperitoneal synovial sarcoma is described. Her presenting symptom was epigastric pain that radiating to the back. On radiologic study, bulky retropancreatic soft tissue mass was detected which showed cystic and solid components. At operation, complete resection of the tumor was not possible because of the adhesion to the vena cava and the liver. During the follow-up, extensive tumor recurrence and liver metastasis were revealed. Primary retroperitoneal synovial sarcoma is a very rare malignant tumor with high mortality and recurrence rates. Retroperitoneal synovial sarcoma usually appears as a nonspecific soft tissue mass that do not have specific imaging features differentiating it from other mesenchymal tumors. However general radiologic findings and anatomic location of the tumor may help the diagnosis. In addition, synovial sarcoma should be included in the differential diagnosis of retroperitoneal soft tissue mass detected in young adults.

Adult↗