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Jun Yong Jeong

Publications and source records attributed to Jun Yong Jeong.

14 recordsLinked to original sources
PubMed2006

Comparison of 5-fluorouracil/leucovorin and capecitabine in preoperative chemoradiotherapy for locally advanced rectal cancer.

PURPOSE: To describe our experience with a bolus injection of 5-fluorouracil and leucovorin (FL) vs. capecitabine in terms of radiologic and pathologic findings in preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer. METHODS: The study enrolled 278 patients scheduled for preoperative CRT using two protocols with different chemotherapeutic regimens. Pelvic radiotherapy (50.4 Gy) was delivered concurrently with FL (n = 145) or capecitabine (n = 133). Surgery was performed 6 weeks after CRT completion. Tumor responses to CRT were measured using both radiologic and pathologic examination. Magnetic resonance volumetry was performed at the initial workup and just before surgery after completion of preoperative CRT. Post-CRT pathology tests were used to determine tumor stage and regression. RESULTS: Radiologic examination showed that tumor volume decreased by 68.2% +/- 20.5% in the FL group and 68.3% +/- 22.3% in the capecitabine group (p = 0.970). Postoperative pathologic T stage determination showed that downstaging occurred in 44.3% of FL and 49.9% of capecitabine patients (p = 0.571). The tumor regression grades after CRT were Grade 1 (minimal response) in 22.6% and 21.0%, Grade 2 (moderate response) in 53.2% and 50.0%, Grade 3 (near-complete response) in 12.9% and 12.9%, and Grade 4 (complete response) in 11.3% and 16.1% of the FL and capecitabine groups, respectively (p = 0.758). CONCLUSION: In the present study, the radiologic and pathologic findings did not reveal significant differences in short-term tumor responses between preoperative FL and capecitabine CRT for locally advanced rectal cancer. Long-term results and a prospective randomized trial are needed.

Adult↗
PubMed2006

Comparison of the accuracy of magnetic resonance imaging and positron emission tomography/computed tomography in the presurgical detection of lymph node metastases in patients with uterine cervical carcinoma: a prospective study.

BACKGROUND: The objective of the current study was to determine the accuracy of magnetic resonance imaging (MRI) and positron emission tomography/computed tomography (PET/CT) for detecting lymph node metastases in patients with uterine cervical carcinoma compared with thin-section histopathologic results from systemic lymphadenectomy. METHODS: Twenty-two patients with International Federation of Obstetrics and Gynecology (FIGO) Stage IB-IVA cervical carcinoma who underwent both MRI and PET/CT before lymphadenectomy were included in this study. Lymphadenectomy involved removing all visible lymph nodes in the surgical fields. To enable region-specific comparisons, paraaortic and pelvic lymph nodes were divided into seven regions: the paraaortic area, both common iliac areas, both external iliac areas, and both internal iliac/obturator areas. Histopathologic evaluation of lymph nodes was the diagnostic standard. Chi-square analysis was used to compare the accuracy of MRI and PET/CT for the detection of metastatic lymph nodes. A P value < or = 0.05 was considered statistically significant. RESULTS: With MRI, the sensitivity, specificity, and accuracy rates for detecting metastatic lymph nodes in each lymph node group were 30.3% (10 of 33 lymph node groups), 92.6% (112 of 121 lymph node groups), and 72.7% (122 of 154 lymph node groups), respectively; with PET/CT, those rates were 57.6% (19 of 33 lymph node groups), 92.6% (112 of 121 lymph node groups), and 85.1% (131 of 154 lymph node groups), respectively. Statistical analysis showed that PET/CT was more sensitive than MRI (P = 0.026) but that there were no statistical differences noted with regard to specificity (P = 1.000) or accuracy (P = 0.180). Power analysis demonstrated that a sample size of 685 lymph node groups (98 patients) would be necessary to demonstrate that PET/CT was more accurate than MRI (alpha = 0.05; beta = 0.80). CONCLUSIONS: PET/CT was more sensitive than MRI for detecting lymph node metastases in patients with uterine cervical carcinoma.

Adult↗
PubMed2006

CT Differentiation of cholangiocarcinoma from periductal fibrosis in patients with hepatolithiasis.

OBJECTIVE: The objective of our study was to determine useful CT findings for differentiating cholangiocarcinoma from periductal fibrosis in patients with hepatolithiasis. MATERIALS AND METHODS: CT images of 30 patients with hepatolithiasis and pathologically proven cholangiocarcinoma (n = 14) or periductal fibrosis (n = 16) were retrospectively reviewed. Helical CT scans were obtained before, 30 seconds after, and 65 seconds after the start of contrast material injection. Analysis of CT findings included evaluation for the presence of periductal soft-tissue density, bile duct wall thickening at the stricture site, ascites, portal vein obliteration, lymph node enlargement, and a duct stone; assessment of the degree of ductal dilatation; and evaluation of the enhancement pattern of periductal lesions, thickened ductal wall, and hepatic parenchyma. The CT attenuation coefficients of the thickened ductal wall and adjacent normal-looking bile duct were measured on images obtained during each phase. Among these findings, statistically significant variables were determined using the Fisher's exact test and Student's t test. Sensitivity and specificity values of the CT criteria were also calculated. RESULTS: The presence of periductal soft-tissue density (p = 0.002), higher enhancement of the duct than adjacent bile duct on portal venous phase images (p = 0.008), ductal wall thickening (p = 0.026), portal vein obliteration (p = 0.031), and lymph node enlargement (p = 0.031) were found to be the significant findings for differentiating cholangiocarcinoma from fibrosis in patients with hepatolithiasis. When any two or more of these five criteria were used in combination, we could identify 100% of the patients with cholangiocarcinoma but only 12.5% of the patients with fibrosis. CONCLUSION: Cholangiocarcinoma in patients with hepatolithiasis can be diagnosed using specific CT criteria.

Aged↗
PubMed2005

Small-bowel obstruction in a phantom model of ex vivo porcine intestine: comparison of PACS stack and tile modes for CT interpretation.

PURPOSE: To compare computed tomographic (CT) image interpretation with picture archiving and communication systems (PACS) stack and tile modes for speed and accuracy of transition zone localization in small-bowel obstruction by using ex vivo porcine specimens. MATERIALS AND METHODS: Twenty-five small-bowel obstruction phantom models made of ex vivo porcine intestines from a slaughterhouse were imaged at CT. One was used for observer training, and 24 were used for experimentation. At 20-cm intervals throughout the intestines, metallic markers were placed in the mesenteries immediately adjacent to bowel. One obstruction was made in each intestine, midway between markers, by ligating intestine with a 3-0 silk suture to simulate mechanical small-bowel obstruction. The lumen proximal to the ligation site was distended with air and a soybean oil-iodized oil mixture until at least two-thirds of the proximal intestine exceeded 2.0 cm in transverse diameter. Dilated segments were 310-550 cm in length. Soybean oil and a mixture of soybean and iodized oil were used to simulate differences in attenuation among bowel wall, intraluminal fluid, and extraluminal abdominal fat. Four experienced abdominal radiologists independently determined the transition zone by using stack mode (cine viewing of stacked images) and, at least 2 weeks later, tile mode (side-by-side image display). Accuracy and degree of error in counting markers were evaluated, and speed of interpretation was recorded. Statistical analysis was performed with the McNemar and Wilcoxon signed rank tests. RESULTS: For all observers, accuracy of transition zone localization tended to be better with stack mode (63%-83% [15-20 phantoms]) than with tile mode (50%-63% [12-15 phantoms]), but the differences were not significant. For each observer, mean counting error was lower in stack mode (range, 0.96-2.48) than in tile mode (range, 1.74-3.22), with significance for three observers (P < .01, P < .01, and P = .04). Interpretation was significantly faster with stack mode by a factor of two to three for all observers (P < .01). CONCLUSION: Stack mode evaluation for identification of the transition zone in obstructed small bowel is faster than evaluation with tile mode. Accuracy is not significantly different between modes, although there is a tendency toward better results with stack mode.

Animals↗
PubMed2005

In vitro CT evaluation of intrahepatic stones: correlation with chemical composition.

OBJECTIVE: To describe in vitro CT features of intrahepatic stones and to correlate CT attenuation with chemical composition. MATERIALS AND METHODS: Of the patients who underwent choledochoscopic intrahepatic stone removal between 1998 and 2001, 54 patients with stones larger than 3 mm were enrolled in this study. In each case, a chemical compositional analysis was performed to determine calcium, cholesterol, total bilirubin, and inorganic phosphorus compositions. The three largest stones obtained from each patient were imaged by CT. CT attenuation numbers were measured in the center images of each stone by drawing free-hand region of interest (ROI). The measured CT attenuation numbers were correlated with their chemical composition. Also, CT attenuation numbers of stones were compared with that of the liver on non-contrast CT (50-70 HU). RESULTS: Stone size ranged from 3.1 to 10.5 mm (mean +/- S.D.: 6.0 +/- 1.4). The CT attenuation numbers (HU) of stones ranged from 36.4 to 410.19 (mean +/- S.D.: 94.6 +/- 49.9). CT numbers of stones were below 70 HU in 11 patients (20.4%), and below 90 HU in 33 patients (59.3%). The chemical analysis data of the stones were as follows: calcium (0.5-6.5 wt.%; mean +/- S.D., 2.6 +/- 1.4), total bilirubin (0.45-24.4 wt.%; 13.1 +/- 6.2), cholesterol (5.4-73.9 wt.%; 29.3 +/- 17.4), phosphorus (0.1-1.2 wt.%; 0.6 +/- 0.3), and non-soluble residue (17.6-85.4 wt.%; 57.0 +/- 22.6). There was a weak but significant correlation between calcium composition and CT attenuation (r = 0.38, P < 0.01) and no significant correlation between other chemical compositions and the CT attenuation (cholesterol, r = 0.01, P > 0.01; total bilirubin, r = 0.05, P > 0.01; phosphorus, r = 0.01, P > 0.01). CONCLUSION: On non-contrast CT, intrahepatic stones would not be hyperattenuating with respect to liver parenchyma in about one fifth of patients. The CT attenuation of stones correlates with calcium and does not correlate with any other chemical composition.

Adult↗
PubMed2005

Hepatic attenuation differences associated with obstruction of the portal or hepatic veins in patients with hepatic abscess.

OBJECTIVE: The purpose of our study was to determine the nature of the association between the attenuation difference of the hepatic parenchyma surrounding an abscess and obstruction of the regional portal vein or of the hepatic vein. MATERIALS AND METHODS: Helical CT scans of 60 patients with hepatic abscess were analyzed for the presence of complete or partial obstruction of the portal or hepatic veins and for attenuation differences in the surrounding parenchyma. Clinical (age, sex, underlying disease, and microorganism) and CT (obstruction of the portal or hepatic vein and number, location, and size of abscesses) findings were analyzed statistically for possible associations with each of regional parenchymal hyper- and hypoattenuation by using the chi-square test and multivariate logistic regression analysis. RESULTS: Regional parenchymal hyperattenuation was identified in 40 patients (67%). More patients with portal vein obstruction showed regional parenchymal hyperattenuation than patients without portal vein obstruction (22/27 patients vs 18/33, p = 0.028), and more patients with hepatic vein obstruction showed regional parenchymal hypoattenuation than those without hepatic vein obstruction (11/21 vs 3/39, p = 0.0003). Multivariate logistic regression analysis showed that portal venous obstruction was the only statistically significant predictor of regional parenchymal hyperattenuation (p = 0.032; odds ratio, 3.7) and that parenchymal hypoattenuation was associated with hepatic venous obstruction (p = 0.001; odds ratio, 44.9). CONCLUSION: Parenchymal hypo- and hyperattenuation are frequently observed in the hepatic region surrounding an abscess on dynamic CT. Moreover, these parenchymal attenuation differences are associated with regional portal or hepatic vein obstruction.

Adult↗
PubMed2004

Palliation of anastomotic obstructions in recurrent gastric carcinoma with the use of covered metallic stents: clinical results in 25 patients.

BACKGROUND: The purpose of this study was to investigate the technical feasibility and the clinical effectiveness of the placement of covered self-expandable metallic stents for the treatment of anastomotic obstructions in recurrent gastric carcinoma. METHODS: With fluoroscopic guidance, covered stents were placed in 25 patients with recurrent gastric carcinoma for the palliation of obstructions at anastomotic sites (14 gastrojejunostomy, 11 esophagojejunostomy). All patients had severe nausea and recurrent vomiting before the stent placement. RESULTS: Stent placement was technically successful in 24 patients (96%). After stent placement, symptoms improved in all 24 patients. During the follow-up of 2 to 65 weeks (mean, 13.7 weeks), stent migration occurred in 1 patient 16 days after the procedure. He needed percutaneous catheter drainage because of an abscess, which was followed by esophagojejunostomy site rupture during a second stent trial. Stricture recurred in 4 patients because of tumor overgrowth 10 to 55 weeks after the procedure; all patients underwent coaxial placement of a second stent and had good oral intake. CONCLUSIONS: The placement of covered expandable metallic stents seems to be both technically feasible and an effective means for the palliation of anastomotic obstructions in recurrent gastric carcinoma. This procedure can be considered to be the primary choice for the palliation in those patients.

Adult↗
PubMed2002

Fluoroscopically guided placement of a covered self-expandable metallic stent for malignant antroduodenal obstructions: preliminary results in 18 patients.

OBJECTIVE: The purpose of this study was to investigate the technical feasibility and the clinical effectiveness of fluoroscopically guided placement of covered self-expandable metallic stents in the treatment of malignant antroduodenal obstructions. SUBJECTS AND METHODS: With fluoroscopic guidance, covered self-expandable metallic stents were placed in 18 consecutive patients with inoperable malignant antroduodenal obstructions. All patients were treated for severe nausea and recurrent vomiting. RESULTS: Stent placement was technically successful in all patients with or without gastrostomy (n = 2) and balloon dilatation (n = 3). After stent placement, symptoms improved in all but one patient, who had another stenosis in the proximal jejunum. During the follow-up of 2-73 weeks (mean, 12 weeks), stent migration occurred in three patients (16.7%) from 1 to 41 days after the procedure. These patients were treated successfully by means of placing a second covered metallic stent. Two patients, who were followed up for longer than 30 weeks, showed a recurrence of strictures because of mechanical failure of the stents; one of the patients was treated with coaxial placement of a second covered metallic stent, which had a positive clinical outcome. CONCLUSION: Fluoroscopically guided placement of covered self-expandable metallic stents is technically feasible and effective for the palliative treatment of inoperable malignant antroduodenal obstructions. The rate of stent migration in our study was lower than those in previous reports.

Adult↗
PubMed2002

Three-dimensional ultrasonography using the minimum transparent mode in obstructive biliary diseases: early experience.

OBJECTIVE: To assess the feasibility of three-dimensional ultrasonography using the minimum transparent mode in patients with obstructive biliary disease. METHODS: Fourteen patients with obstructive jaundice underwent three-dimensional ultrasonography after conventional two-dimensional ultrasonography before interventional procedures. Three-dimensional images reconstructed by the minimum transparent mode were evaluated and compared with direct cholangiography. The minimum transparent mode images were compared with the two-dimensional ultrasonographic images to determine whether additional information was obtained. RESULTS: The level of obstruction was correctly depicted in all patients, and a dilated common bile duct, common hepatic duct, gallbladder, and main intrahepatic ducts were well visualized on minimum transparent mode images. The findings on minimum transparent mode images were well correlated with those on cholangiography; however, the perspective of the whole biliary tree on minimum transparent mode images was inferior to that on cholangiography in all cases. The overall image quality of minimum transparent mode images was poor in 6 patients, fair in 3, good in 4, and excellent in 1. The biliary anatomy was more objectively visualized on the minimum transparent mode images than conventional two-dimensional ultrasonographic images. CONCLUSIONS: Three-dimensional ultrasonography using the minimum transparent mode appears to be clinically feasible. The biliary anatomy was more objectively visualized on the minimum transparent mode images than conventional two-dimensional ultrasonographic images. Further technical development is needed to improve imaging resolution.

Aged↗
PubMedDate not supplied

MR findings of renal cortical necrosis.

PURPOSE: Evaluating the MR findings of renal cortical necrosis was the purpose of this study. METHOD: Eight series of T1-/T2-weighted (n = 8) and contrast-enhanced T1-weighted (n = 4) MR images in six patients with renal cortical necrosis diagnosed by renal biopsy (n = 4) or on clinical grounds (n = 2) were reviewed. In those who had follow-up MRI (n = 2) or comparable CT (n = 3), interval changes of MR findings and comparison with CT images were done. RESULTS: Swollen kidney with dark signal intensity rim involving the inner cortex and column of Bertin was noted on T2-and T1-weighted images. It was more conspicuous on T2-weighted images. The lesion did not enhance and was differentiated from uninvolved renal parenchyma. In the follow-up MRI, thickened dark signal intensity was more prominent and proved to be calcification or fibrosis. CONCLUSION: MRI, especially T2-weighted and contrast-enhanced T1-weighted imaging, was helpful in evaluating renal cortical necrosis.

Adult↗
PubMedDate not supplied

Atypical low-signal-intensity renal parenchyma: causes and patterns.

Certain renal diseases manifest as low signal intensity of the renal parenchyma on magnetic resonance images. Sometimes, the appearance is sufficiently characteristic to allow a specific radiologic diagnosis to be made. The causes of this finding can be classified into three main categories on the basis of the pathophysiology: hemolysis, infection, and vascular disease. The first category includes paroxysmal nocturnal hemoglobinuria (PNH), hemosiderin deposition in the renal cortex from mechanical hemolysis, and sickle cell disease. The second category includes hemorrhagic fever with renal syndrome (HFRS). The third category includes acute renal vein thrombosis, renal cortical necrosis, renal arterial infarction, rejection of a transplanted kidney, and acute nonmyoglobinuric renal failure with severe loin pain and patchy renal vasoconstriction. These disease processes have different patterns of low signal intensity. PNH, hemosiderin deposition from mechanical hemolysis, and sickle cell disease involve the entire cortex including the columns of Bertin. HFRS involves the medulla, especially the outer medulla, whereas cortical necrosis involves the inner cortex including the columns of Bertin. In renal vein thrombosis, low-signal-intensity lesions involve the outer medulla, an appearance resembling that of HFRS. Wedge-shaped low-signal-intensity regions involving both the cortex and the medulla are seen in arterial infarction.

Humans↗
PubMedDate not supplied

Ruptured corpus luteal cyst: CT findings.

OBJECTIVE: To evaluate the CT findings of ruptured corpus luteal cysts. MATERIALS AND METHODS: Six patients with a surgically proven ruptured corpus luteal cyst were included in this series. The prospective CT findings were retrospectively analyzed in terms of the size and shape of the cyst, the thickness and enhancement pattern of its wall, the attenuation of its contents, and peritoneal fluid. RESULTS: The mean diameter of the cysts was 2.8 (range, 1.5-4.8) cm; three were round and three were oval. The mean thickness of the cyst wall was 4.7 (range, 1-10) mm; in all six cases it showed strong enhancement, and in three was discontinuous. In five of six cases, the cystic contents showed high attenuation. Peritoneal fluid was present in all cases, and its attenuation was higher, especially around the uterus and adnexa, than that of urine present in the bladder. CONCLUSION: In a woman in whom CT reveals the presence of an ovarian cyst with an enhancing rim and highly attenuated contents, as well as highly attenuated peritoneal fluid, a ruptured corpus luteal cyst should be suspected. Other possible evidence of this is focal interruption of the cyst wall and the presence of peritoneal fluid around the adnexa.

Adult↗