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Featured researches published by Hyung Sik Yoo.


American Journal of Roentgenology | 2006

Solid Pseudopapillary Tumor of the Pancreas: Typical and Atypical Manifestations

Jin Young Choi; Myeong-Jin Kim; Joo Hee Kim; Seung Hyoung Kim; Joon Sok Lim; Young Taik Oh; Jae-Joon Chung; Hyung Sik Yoo; Jong Tae Lee; Ki Whang Kim

OBJECTIVE The purpose of this pictorial essay is to illustrate the various appearances of solid pseudopapillary tumor of the pancreas. CONCLUSION Solid pseudopapillary tumor of the pancreas is a rare neoplasm usually found in young women. Typical solid pseudopapillary tumor is characterized by a well-encapsulated mass with varying amounts of intratumoral hemorrhage. However, the tumor can have an atypical appearance, such as metastasis, ductal obstruction, parenchymal and extracapsular invasion, simulation of islet cell tumor, intratumoral calcification, and occurrence in a male patient. The typical and atypical manifestations of solid pseudopapillary tumor can be visualized with cross-sectional imaging.


Journal of Clinical Ultrasound | 1997

Sonographic findings in tuberculous epididymitis and epididymo-orchitis

Jae Joon Chung; Myeong-Jin Kim; Tack Lee; Hyung Sik Yoo; Jong Tae Lee

This paper presents the sonographic findings in scrotums of patients affected with tuberculous epididymitis or epididymo‐orchitis.


Korean Journal of Radiology | 2006

Comparison of CT and 18F-FDG pet for detecting peritoneal metastasis on the preoperative evaluation for gastric carcinoma.

Joon Seok Lim; Myeong Jin Kim; Mi Jin Yun; Young Tak Oh; Joo Hee Kim; Hee Sung Hwang; Mi-Suk Park; Seoung Whan Cha; Jong Doo Lee; Sung Hoon Noh; Hyung Sik Yoo; Ki Whang Kim

Objective The aim of our study was to compare the accuracy of CT and 18F-FDG PET for detecting peritoneal metastasis in patients with gastric carcinoma. Materials and Methods One-hundred-twelve patients who underwent a histologic confirmative exam or treatment (laparotomy, n = 107; diagnostic laparoscopy, n = 4; peritoneal washing cytology, n = 1) were retrospectively enrolled. All the patients underwent CT and 18F-FDG PET scanning for their preoperative evaluation. The sensitivities, specificities and accuracies of CT and 18F-FDG PET imaging for the detection of peritoneal metastasis were calculated and then compared using Fishers exact probability test (p < 0.05), on the basis of the original preoperative reports. In addition, two board-certified radiologists and two board-certified nuclear medicine physicians independently reviewed the CT and PET scans, respectively. A receiver-operating characteristic curve analysis was performed to compare the diagnostic performance of CT and 18F-FDG PET imaging for detecting peritoneal metastasis. Results Based on the original preoperative reports, CT and 18F-FDG PET showed sensitivities of 76.5% and 35.3% (p = 0.037), specificities of 91.6% and 98.9% (p = 0.035), respectively, and equal accuracies of 89.3% (p = 1.0). The receptor operating characteristics curve analysis showed a significantly higher diagnostic performance for CT (Az = 0.878) than for PET (Az = 0.686) (p = 0.004). The interobserver agreement for detecting peritoneal metastasis was good (κ value = 0.684) for CT and moderate (κ value = 0.460) for PET. Conclusion For the detection of peritoneal metastasis, CT was more sensitive and showed a higher diagnostic performance than PET, although CT had a relatively lower specificity than did PET.


American Journal of Roentgenology | 2009

Typical and atypical manifestations of serous cystadenoma of the pancreas: imaging findings with pathologic correlation.

Jin-Young Choi; Myeong-Jin Kim; Jae Young Lee; Joon Seok Lim; Jae Joon Chung; Ki Whang Kim; Hyung Sik Yoo

OBJECTIVE The purpose of this article is to present the typical and atypical manifestations of serous cystadenoma, which can be visualized with cross-sectional imaging. CONCLUSION Serous cystadenomas of the pancreas have various distinguishing imaging features. Typically, a serous cystadenoma is morphologically classified as having either a polycystic, honeycomb, or oligocystic pattern. Atypical manifestations of serous cystadenoma can include giant tumors with ductal dilatation, intratumoral hemorrhages, solid variants, unilocular cystic tumors, interval growth, and a disseminated form.


Journal of Magnetic Resonance Imaging | 2002

Characterization of focal hepatic lesions with ferumoxides-enhanced MR imaging: utility of T1-weighted spoiled gradient recalled echo images using different echo times.

Joo Hee Kim; Myeong-Jin Kim; Sang Hyun Suh; Jae-Joon Chung; Hyung Sik Yoo; Jong Tae Lee

To evaluate the different signal characteristics of focal hepatic lesions on ferumoxides‐enhanced MR imaging, including T1‐weighted spoiled gradient recalled echo (GRE) images using different echo times (TE) and T2‐ and T2*‐weighted images.


Clinical Nuclear Medicine | 1986

Evaluation of intrahepatic I-131 ethiodol on a patient with hepatocellular carcinoma. Therapeutic feasibility study.

Chan H. Park; Jung Ho Suh; Hyung Sik Yoo; Jong T. Lee; Dong Ik Kim

This study assesses the therapeutic efficacy of radiolabeled iodized oil on a patient with hepatocellular carcinoma (HCC). An iodized oil, such as Lipiodol or Ethiodol (Savage Laboratories, Melville, NY), was retained selectively in the tumor vessels of large tumors as well as in the daughter tumors of HCC for long periods of time following intra-arterial injection into the hepatic artery proper. A small fraction of the stable iodine (1 pg of I-127) of the 37% iodine by weight in Ethiodol was replaced by the I-131 with 100% efficiency. A patient with HCC was injected with I-131 Ethiodol into the hepatic artery. Sequential imaging of organs such as the liver, lung, stomach, and thyroid over an eight-day period demonstrated a high tumor-to-normal-liver ratio and a negligible amount of radioactivity in these organs. These findings indicate that I-131 Ethiodol, or Ethiodol labeled with other pure beta emitters, such as Y-90 or P-32, will be effective delivering a high internal radiation dose to HCC with a small radiation effect to normal tissues. To evaluate its potential as a radiotherapeutic agent for HCC, the kinetics, biodistribution, determination of absolute activity in the tumor following intra-arterial injection of I-131 Ethiodol will be studied in the future. At the same time, an effort will be made to label Ethiodol with Y-90 and P-32.


Cancer Chemotherapy and Pharmacology | 1989

Radioiodinated fatty acid esters in the management of hepatocellular carcinoma: preliminary findings

Hyung Sik Yoo; Chan Hee Park; Jung Ho Suh; Jong Tae Lee; Dong Ik Kim; Byung Soo Kim; M.T. Madsen

SummaryRadioiodinated fatty acid esters, such as lipiodol or ethiodol, are localized in the hypervascular hepatocellular carcinoma (HCC) for a long time following intra-arterial hepatic injection, enabling delivery of high internal radiation to the tumor. The desired radiation can easily be delivered to small HCC, less than 5 cm in diameter, in single or multiple procedures with an 8-week interval. For larger tumors, [131I]lipiodol or [131I]ethiodol in conjunction with chemotherapy emulsion, Ivalon embolization or all three combinations should be considered for maximal clinical results. A strong beta emitter with shorter physical half-life, i.e.90Y will be more effective in the management of HCC if one can label lipiodol with90Y.


Cancer | 1991

Nodular hepatocellular carcinoma. Treatment with subsegmental intraarterial injection of iodine 131‐labeled iodized oil

Hyung Sik Yoo; Jong Tae Lee; Ki Whang Kim; Byung Soo Kim; Heung Jai Choi; Kyong Sik Lee; Chan Ii Park; Chang Yun Park; Jung Ho Suh; John J.K. Loh

Internal radiation therapy with subsegmental arterial injection of iodine 131(131I)‐labeled iodized oil (Lipiodol; Laboratorie, Guerbet, France) was evaluated in 24 patients with nodular hepatocellular carcinoma (HCC) ranging from 2.5 to 8.0 cm in size. 131I Lipiodol (555 to 2220 MBq in 3 to 8 ml) was injected depending on the tumor size. Tumor reduction was seen in 88.9% of tumors smaller than 4.0 cm in diameter, 65.5% of tumors between 4.1 to 6.0 cm, and 25.0% of tumors larger than 5.1 cm. The tumor size reduction corresponded to the gradual drop of serum alphafetoprotein (AFP) levels and devascularization on follow‐up angiography. Adverse reactions from treatment included fever, mild abdominal pain, nausea, and elevation of transaminases. These were mild and well tolerated by patients. This method provided long‐term local control without complications related to the thyroid, lung, gastrointestinal tract, and bone marrow.


Journal of Computer Assisted Tomography | 2002

Radiologic findings of gastrointestinal tract involvement in hepatocellular carcinoma.

Mi-Suk Park; Ki Whang Kim; Jeong-Sik Yu; Myeong-Jin Kim; Sang-Wook Yoon; Ki-Woong Chung; Jong Tae Lee; Hyung Sik Yoo

Purpose The purpose of this work was to evaluate the radiologic findings of gastrointestinal (GI) tract involvement in hepatocellular carcinoma (HCC) and to discuss mechanisms of spread. Method Eighteen patients with histologically proven GI tract metastasis in HCC for 4.5 years underwent CT and five also underwent upper GI (UGI) series. The cases were classified according to the mode of spread, based on the radiologic findings. Results The involved portion of the GI tract was the stomach (n = 11), duodenum (n = 4), and colon (n = 4). The mode of spread was direct invasion from a contiguous primary tumor (n = 12), hematogenous metastasis (n = 3), peritoneal seeding (n = 1), and undetermined (n = 2). In cases of direct invasion from contiguous primary tumors, CT revealed GI tract invasion directly from bulky hepatic masses (n = 9) or daughter masses at the portion of the bowel wall contiguous to the hepatic masses (n = 3). In cases of hematogenous spread, CT revealed an intramural mass in the stomach and duodenum (n = 2) or a diffuse thickening of the wall of the stomach (n = 1). In the case of peritoneal seeding, CT revealed multiple small nodules in the right paracolic gutter, omentum, and mesentery with invasion to the colon. Conclusion GI tract involvement in HCC shows various radiologic findings according to the mode of spread, but the most common finding is direct invasion of the stomach, duodenum, or colon from contiguous primary tumor. Index Terms: Computed tomography—Gastrointestinal tract—Gastrointestinal tract, neoplasms—Liver, neoplasms.


CardioVascular and Interventional Radiology | 2003

Supplemental transcatheter arterial chemoembolization through a collateral omental artery: Treatment for hepatocellular carcinoma

Jong Yun Won; Do Yun Lee; Jong Tae Lee; Sung Il Park; Myeong-Jin Kim; Hyung Sik Yoo; Sang-Hyun Suh; Sang Joon Park

AbstractPurpose: To evaluate the therapeutic efficacy and safety of supplemental transcatheter arterial chemoembolization (TACE) through the extrahepatic collateral omental artery (OA) for the treatment of hepatocellular carcinoma (HCC). Methods: We studied 21 patients with extrahepatic collaterals of the OA, among 1,512 patients with HCC who had undergone angiography. HCCs supplied by collateral OAs were located at: segment IV in seven, segment V in five, segment III in three, segment VI in three and segment VIII in three patients (Couinaud classification of segments). On preoperative CT scans, every HCC was abutting the liver surface. Adjacent omental infiltration or engorgement was noted in 11 patients. Celiac and hepatic arteriograms showed hypertrophy of the feeding OA in all patients. TACE of the OA was performed in 19 patients with an emulsion of iodized oil and doxorubicin hydrochloride. Embolization with gelatin sponge particles was added in five patients. Results: Collaterals of the OA to the HCC were found on the first to seventeenth sessions of TACE. On follow-up CT scans, five patients showed complete uptake of iodized oil in the tumor. Partial uptake of iodized oil was noted in 13 patients and no uptake in one patient. There was no serious complication that related to the omental embolization, such as omental or bowel ischemia. The cumulative survival rates from the time of the TACE of the OA were 81% at 6 months and 68% at 12 months. Conclusion: TACE of the OA is safe and has a potential therapeutic effect in the treatment of HCC.

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