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Featured researches published by Ki Choon Sim.


Acta Radiologica | 2017

Correlation of CT imaging features and tumor size with Fuhrman grade of clear cell renal cell carcinoma

Saelin Oh; Deuk Jae Sung; Kyung Sook Yang; Ki Choon Sim; Na Yeon Han; Beom Jin Park; Min Ju Kim; Sung Bum Cho

Background Identification of clinical features to determine the aggressive potential of tumors is highly warranted to stratify patients for adequate treatment. Computed tomography (CT) imaging features of clear cell renal cell carcinoma (ccRCC) may contribute to personalized risk assessment. Purpose To assess the correlation between CT imaging features and Fuhrman grade of ccRCC, and to identify the predictors of high Fuhrman grade in conjunction with tumor size. Material and Methods CT scans of 169 patients with 173 pathologically proven ccRCCs were retrospectively reviewed in consensus by two radiologists for the presence of intratumoral necrosis and intratumoral cyst and tumor size. Histologic grade was classified as either low (Fuhrman grade I or II) or high (Fuhrman grade III or IV). Statistical significance was evaluated by using univariate, multivariate regression, receiver operating characteristic (ROC) curve, and Spearman correlation analyses. Results On CT, 20 of the 173 tumors had intratumoral cysts, 60 had intratumoral necrosis, and 93 showed entirely solid tumors. The odds of high grade were higher with intratumoral necrosis and entirely solid tumor than with intratumoral cyst (P < 0.03). Intratumoral necrosis showed a significantly high odds ratio of 25.73 for high Fuhrman grade. The ROC curve showed a threshold tumor size of 36 mm to predict high Fuhrman grade for overall tumors (area under the ROC curve, 0.70). In ccRCCs with intratumoral necrosis or cyst, tumor size did not significantly correlate with Fuhrman grade. Conclusion Intratumoral necrosis on CT was a strong and independent predictor of biologically aggressive ccRCCs, irrespective of tumor size.


Abdominal Radiology | 2017

Renal tumors with low signal intensities on T2-weighted MR image: radiologic-pathologic correlation

Youyeon Kim; Deuk Jae Sung; Ki Choon Sim; Na Yeon Han; Beom Jin Park; Min Ju Kim; Sung Bum Cho

Accurate characterization of renal masses is essential for ensuring appropriate management. Low T2 signal intensity is a common feature of papillary renal cell carcinoma and fat-poor angiomyolipoma. Nonetheless, other types of renal cell carcinoma, oncocytoma, hemangioma, lymphoma, leiomyoma, and urothelial cell carcinoma also can show low signal intensities on T2-weighted imaging (T2WI). Histopathologic features that can lead to low T2 signal intensities in renal tumors include smooth muscle component, papillary architecture, a high nucleus-to-cytoplasm ratio, and hemorrhage. To establish an appropriate differential diagnosis for renal tumors on MRI, it is necessary to understand the relationship between the MR signal intensities and the histopathologic and morphologic features, in addition to contrast enhancement patterns and diffusion characteristics of the tumors.


American Journal of Roentgenology | 2017

Hepatic Parenchymal Heterogeneity as a Marker for Oxaliplatin-Induced Sinusoidal Obstruction Syndrome: Correlation With Treatment Response of Colorectal Cancer Liver Metastases

Na Yeon Han; Beom Jin Park; Kyung Sook Yang; Min Ju Kim; Deuk Jae Sung; Ki Choon Sim; Sung Bum Cho

OBJECTIVE The objective of our study was to evaluate the influence of oxaliplatin-based chemotherapy (OBC)-induced hepatic parenchymal heterogeneity detected on contrast-enhanced CT scans on response of liver metastasis. We chose to study hepatic parenchymal heterogeneity on the basis of the assumption that hepatic parenchymal heterogeneity may indicate the presence of chemotherapy-induced sinusoidal obstruction syndrome (SOS). MATERIALS AND METHODS For this retrospective study, 104 patients with hepatic metastases from colorectal cancer (male-female ratio, 66:38; age range, 20-80 years) who had undergone OBC and serial CT studies were consecutively registered. Two blinded imagers independently scored CT images using a 5-point scale to determine the severity of newly developed hepatic parenchymal heterogeneity after OBC. Subsequently, two radiologists evaluated tumor response to OBC using a 4-point ordinal scale. We performed generalized estimating equation (GEE) analysis using cumulative logits to account for the effect of hepatic parenchymal heterogeneity severity on the cumulative tumor response probability. RESULTS The interobserver agreements for the severity of hepatic parenchymal heterogeneity were excellent (κ = 0.825). GEE analyses showed that the severity of post-OBC hepatic parenchymal heterogeneity, number of chemotherapy sessions, and presence of other organ metastases were significant predictors of tumor response; these three factors also showed significance in the final GEE model (p < 0.0001 for severity of hepatic parenchymal heterogeneity for both readers; p = 0.011 and 0.010 for the number of chemotherapy sessions for readers 1 and 2; p = 0.046 and 0.012 for the presence of other organ metastases for readers 1 and 2). CONCLUSION Hepatic parenchymal heterogeneity detected on contrast-enhanced CT of patients with hepatic metastases from colorectal cancer who have undergone OBC may indicate the presence of SOS, and the more severe the SOS, the worse the tumor response of hepatic metastasis to oxaliplatin is expected to be.


Journal of Obstetrics and Gynaecology | 2017

A rare case of vulvar angiomyofibroblastoma: MRI findings and literature review

Saelin Oh; Deuk Jae Sung; Ki Choon Sim; Na Yeon Han; Beom Jin Park; Min Ju Kim; Jae Yun Song; Joo Young Kim

Saelin Oh, Deuk Jae Sung, Ki Choon Sim, Na Yeon Han, Beom Jin Park, Min Ju Kim, Jae Yun Song and Joo Young Kim Department of Radiology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea; Department of Obstetrics and Gynecology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea; Department of Pathology, Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea


Journal of Computer Assisted Tomography | 2017

Magnetic Resonance Imaging-Based Prostate-Specific Antigen Density for Prediction of Gleason Score Upgrade in Patients with Low-Risk Prostate Cancer on Initial Biopsy

Ki Choon Sim; Deuk Jae Sung; Kun Woo Kang; Kyung Sook Yang; Na Yeon Han; Beom Jin Park; Min Ju Kim; Sung Bum Cho

Objective The aim of this study was to assess the utility of prostate-specific antigen density (PSAD) calculated using magnetic resonance imaging for predicting Gleason score (GS) upgrade in patients with low-risk prostate cancer on biopsy. Methods Seventy-three patients were divided into 2 groups according to the concordance between biopsy and prostatectomy GS: group 1 (6/6) and group 2 (6/≥7). Magnetic resonance imaging–based PSAD, prostate volume, prostate-specific antigen (PSA), and age were compared between the 2 groups. Logistic regression and receiver operating characteristic curve analysis were performed. Results Gleason score was upgraded in 40 patients. Patients in group 2 had significantly higher PSAD and PSA values and smaller prostate volume than did those in group 1. Prostate-specific antigen density of 0.26 ng/mL per cm3 or higher, PSA of 7.63 ng/mL or higher, and prostate volume of 25.1 cm3 or less were related to GS upgrade, with area-under-the-curve values of 0.765, 0.721, and 0.639, respectively. Conclusions Magnetic resonance imaging–based PSAD could help in predicting postoperative GS upgrade in patients with low-risk prostate cancer.


British Journal of Radiology | 2016

Perirenal fat stranding on CT: is there an association with bladder outlet obstruction?

Na Y Han; Deuk Jae Sung; Min J Kim; Beom Jin Park; Ki Choon Sim; Sung B Cho

OBJECTIVE To determine the association between perirenal fat stranding (PFS) on CT and bladder outlet obstruction (BOO). METHODS CT scans from 122 patients who had undergone urodynamic study for lower urinary tract symptoms (LUTS) were registered after exclusion of patients with renal or retroperitoneal disease. Images were independently reviewed by two radiologists and compared with those of 244 age- and sex-matched control patients without LUTS. The PFS severity was scored on a four-point scale, and the interobserver agreement was assessed with kappa statistics. The severity score and incidence was compared between the groups, and the association with baseline characteristics was analyzed. For the LUTS group, an association between PFS severity and urodynamic and laboratory data was evaluated. RESULTS PFS was more frequent and more severe in the LUTS group than in the control group (p-value < 0.001); its presence was significantly associated with male gender and older age (p-value < 0.001). PFS was predominantly bilateral in both groups (80.1-93.2%). In the LUTS group, PFS severity scores were significantly correlated with the maximum flow rate, maximum detrusor pressure and estimated glomerular filtration rate (p-value < 0.001). Interobserver agreements were excellent for PFS presence (κ = 0.883) and severity (κ = 0.816). CONCLUSION Severe PFS was observed in older, male patients with LUTS. PFS severity was associated with the degree of BOO and impaired renal function. ADVANCES IN KNOWLEDGE Recognition of PFS on the CT scan may warrant further evaluation of BOO and appropriate management to prevent renal impairment.


Korean Journal of Anesthesiology | 2014

Unusual venous route of pulmonary artery catheter in a liver transplant recipient: pericardiophrenic or highest intercostal vein?: a case report

Ji Hyun Park; Ki Choon Sim; Sooho Lee; Gyu-Sam Hwang

We report an extraordinary case in which the venous route for pulmonary artery catheterization was unusual. A 41 year-old woman with an end-stage liver disease underwent a living-donor liver transplantation. After induction of anesthesia, the pulmonary artery catheter was revealed to be advanced into the left brachiocephalic vein and then slipped into another vein that drains into the left brachiocephalic vein. In this case, we assumed that the catheter had most likely slipped into the left pericardiophrenic vein since the catheter follows the left heart border similarly to the route of this vein according to the chest X-ray. Patients with liver cirrhosis develop many collateral vessels and have enlarged veins due to portal hypertension, which makes this vascular route possible. We present this case for anesthesiologists to be aware of the possibilities of unusual venous route due to dilated collateral vessels especially in liver transplant patients.


Clinical Imaging | 2018

Computed tomography and magnetic resonance imaging findings of pancreatic hamartoma: A case report and literature review

Yeo Eun Han; Beom Jin Park; Deuk Jae Sung; Min Ju Kim; Na Yeon Han; Ki Choon Sim; Sung Bum Cho; Joo Young Kim

Pancreatic hamartoma is a rare benign malformation that resembles a neoplasm and may be mistaken for a malignancy. The imaging findings of pancreatic hamartoma are not well established, as only one radiological case report has been described since 1983. Herein, we discussed a case of pancreatic hamartoma in a 35-year-old woman and conducted a literature review focused on imaging findings and differential diagnosis of pancreatic hamartoma. Increased late enhancement on post-contrast dynamic study and absence of diffusion restriction may be characteristic MR imaging findings of pancreatic hamartoma that may narrow the differential diagnosis of hypervascular pancreatic lesions.


Abdominal Radiology | 2018

Preoperative CT findings of subclinical hernia can predict for postoperative inguinal hernia following robot-assisted laparoscopic radical prostatectomy

Ki Choon Sim; Deuk Jae Sung; Na Yeon Han; Beom Jin Park; Min Ju Kim; Sung Bum Cho; Kyung Sook Yang

PurposeTo evaluate preoperative CT features that predict the development of postoperative inguinal hernia after robot-assisted laparoscopic radical prostatectomy (RALRP).MethodsWe enrolled 160 men who underwent CT, subsequent RALRP, and at least three years of follow-up. CT was retrospectively reviewed in consensus by two radiologists for the presence of asymmetric spermatic cord fat and scrotal fluid collection. The diagnostic power of each CT feature for the development of postoperative inguinal hernia was calculated. Multiple logistic regression was performed to evaluate the association between CT features, clinical variables, and postoperative inguinal hernia.ResultsSurgically confirmed postoperative inguinal hernia developed in 17 patients. Asymmetric spermatic cord fat was demonstrated in 13 patients, and scrotal fluid collection was seen in 59 patients. The diagnostic values of asymmetric spermatic cord fat and scrotal fluid collection for postoperative inguinal hernia were 58.8% and 88.2% sensitivity, 97.9% and 69.2% specificity, 76.9% and 25.4% positive predictive value, 95.2% and 98.0% negative predictive value, and 93.8% and 71.3% accuracy, respectively. On multiple logistic regression analysis, asymmetric spermatic cord fat, scrotal fluid collection, and low BMI were significant predictive factors for the development of postoperative inguinal hernia (odds ratios: 135.8, 31.6, and 0.7, respectively).ConclusionThe presence of asymmetric spermatic cord fat or scrotal fluid collection was significantly associated with the development of postoperative inguinal hernia.


Abdominal Radiology | 2016

Non-invasive assessment of liver fibrosis using acoustic structure quantification: comparison with transient elastography in chronic viral hepatitis

Tae Hoon Nam; Beom Jin Park; Deuk Jae Sung; Min Ju Kim; Na Yeon Han; Ki Choon Sim; Jean H. Lee; Sung Bum Cho

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