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Hyo-Sung Kwak

Publications and source records attributed to Hyo-Sung Kwak.

17 recordsLinked to original sources
PubMed2005

Stents in common iliac vein obstruction with acute ipsilateral deep venous thrombosis: early and late results.

PURPOSE: To evaluate, by imaging and clinical follow-up, the effectiveness and long-term results of stent placement in cases of common iliac vein obstruction associated with ipsilateral deep vein thrombosis (DVT). MATERIALS AND METHODS: Retrospective analysis of 22 patients (13 women, nine men; median age, 58 years) with common iliac vein obstruction with ipsilateral DVT was performed for this study. All patients presented with leg edema or pain and were treated with catheter-directed thrombolysis (1,000-2,000 U urokinase per kg body weight per hour; n = 19), aspiration thrombectomy (n = 21), or angioplasty (n = 14) followed by stent placement (n = 22) via an ipsilateral popliteal vein approach (right, n = 2; left, n = 20) under ultrasonographic (US) guidance. Patients were then followed by duplex US, and patency rates were determined by Kaplan-Meier survival analysis. RESULTS: The mean procedure time was 15 hours (range, 1-23 hours) and the mean urokinase dose was 1,980,000 U (range, 600,000-3,600,000 U) before the implantation of 27 stents. Three patients did not receive urokinase. The technical success rate was 96% (26 of 27 stents) and the clinical success rate was 95% (21 of 22 patients). The causes of common iliac vein obstruction were May-Thurner syndrome (n = 16), pelvic mass (n = 2), and unknown (n = 4). The early complications included upward stent migration in one patient and a spinal epidural hematoma in another. The late complication was partial stent obstruction, which was successfully treated by thrombolysis and angioplasty in one patient. Follow-up lasted 1-41 months (mean, 21.4 months). Overall, the 1-year and 2-year primary patency rates were both 95% and the 1-year and 2-year secondary patency rates were both 100%. CONCLUSION: Directed catheter thrombolysis and aspiration of DVT are relatively safe, and the use of stents improves patency results in cases of common iliac vein obstruction.

Adult↗
PubMed2005

Comparison of renal damage by iodinated contrast or gadolinium in an acute renal failure rat model based on serum creatinine levels and apoptosis degree.

This study was undertaken to compare renal damage, as determined by serum creatinine and degree of apoptosis, caused by iodinated contrast or gadolinium in an acute renal failure (ARF) rat model. Rats were divided into three groups; controls (n=3), a CT contrast medium group (n=9), and an MR contrast medium group (n=9). The CT and MR groups were further subdivided into three groups, namely, low, standard, and high dose subgroups. Renal function was evaluated by determining serum creatinine levels; before ARF, and 48 hr after ARF and contrast administration. Apoptosis was assayed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). No significant creatinine level differences were observed between the CT and MR groups (p=0.116). Degrees of apoptosis in the renal cortex and medulla were more severe in the CT contrast medium group than in the control or MR contrast medium group (p<0.05). The study shows that CT contrast medium did not aggravate renal function more so than MR contrast medium in this ARF rat model. However, apoptosis examination in the renal cortex and medulla indicated that CT contrast medium induced more severe apoptosis than MR contrast medium (p<0.05). We conclude that CT contrast medium can be used for renal imaging studies when subjects are well hydrated and preventive medication is administered.

Acute Kidney Injury↗
PubMed2004

Detection of hepatocellular carcinoma: comparison of ferumoxides-enhanced and gadolinium-enhanced dynamic three-dimensional volume interpolated breath-hold MR imaging.

The purpose was to compare the diagnostic accuracy of ferumoxides-enhanced MR imaging and gadolinium-enhanced dynamic MR imaging using three-dimensional (3D) volume interpolated breath-hold examination (VIBE) for the detection of hepatocellular carcinoma (HCC). Forty-nine patients with 61 HCCs, who underwent ferumoxides-enhanced and gadolinium-enhanced dynamic MR imaging, were included prospectively in this study. Ferumoxides-enhanced MR imaging was performed 24 h after completion of the dynamic study using 3D-VIBE. Three radiologists independently interpreted the images. The diagnostic accuracy was evaluated using the receiver-operating characteristic method, and the sensitivity of each imaging technique was compared using McNemar's test. The mean diagnostic accuracy of dynamic MR imaging (Az=0.95) was higher than that of ferumoxides-enhanced MR imaging (Az=0.90), but failed to reach a statistical significance (P=0.057). The mean sensitivity of dynamic MR imaging (90.7%) was significantly superior to that of ferumoxides-enhanced MR imaging (80.9%, P=0.03). Furthermore, for lesions smaller than 15 mm, the mean sensitivity of dynamic MR imaging was significantly higher than that of ferumoxides-enhanced MR imaging (85.2% vs. 69.2%, P<0.05). Dynamic MR imaging showed a trend toward better diagnostic accuracy for than ferumoxides-enhanced MR imaging for the detection of HCCs.

Aged↗
PubMed2003

MR imaging of calcifying aponeurotic fibroma of the thigh.

Calcifying aponeurotic fibroma is a rare, benign soft-tissue proliferation that occurs in the distal extremities in children. Because this lesion has a tendency to recur after surgical resection, MR imaging to determine the extent of the tumor for surgical planning is optimal. We report the MR findings in a 4-year-old boy with a calcifying aponeurotic fibroma of the thigh.

Calcinosis↗
PubMed2003

Preoperative detection of hepatocellular carcinoma: comparison of combined contrast-enhanced MR imaging and combined CT during arterial portography and CT hepatic arteriography.

The aim of this study was to compare Gd-DTPA-enhanced dynamic MR images, superparamagnetic iron oxide (SPIO)-enhanced MR images, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images, vs combined CT arterial portography (CTAP) and CT hepatic arteriography (CTHA), in the detection of hepatocellular carcinoma (HCC) using receiver operating characteristic (ROC) analysis. Twenty-four patients with 38 nodular HCCs (5-60 mm, mean 23.0 mm) were retrospectively analyzed. Image reviews were conducted on a liver segment-by-segment basis. A total of 192 segments, including 36 segments with 38 HCC, were reviewed independently by three radiologists. Each radiologist read four sets of images (set 1, unenhanced and Gd-DTPA-enhanced dynamic MR images; set 2, unenhanced and SPIO-enhanced MR images; set 3, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images; set 4, combined CTAP and CTHA). To minimize any possible learning bias, the reviewing order was randomized and the reviewing procedure was performed in four sessions at 2-week intervals. The diagnostic accuracy (A(z) values) for HCCs of combined CTAP and CTHA, combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images, Gd-DTPA-enhanced dynamic MR images, and SPIO-enhanced MR images for all observers were 0.934, 0.963, 0.878, and 0.869, respectively. The diagnostic accuracy of combined CTAP and CTHA and combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images was significantly higher than Gd-DTPA-enhanced dynamic MR images or SPIO-enhanced MR images ( p<0.005). The mean specificity of combined CTAP and CTHA (93%) and combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images (95%) was significantly higher than Gd-DTPA-enhanced dynamic MR images (87%) or SPIO-enhanced MR images (88%; p<0.05). Combined Gd-DTPA-enhanced dynamic and SPIO-enhanced MR images may obviate the need for more invasive combined CTAP and CTHA for the preoperative evaluation of patients with HCC.

Adult↗
PubMed2003

Flared polyurethane-covered self-expandable nitinol stent for malignant biliary obstruction.

PURPOSE: To determine the technical efficacy and safety of a flared polyurethane-covered self-expandable nitinol stent in the management of malignant biliary obstruction and to evaluate its clinical efficacy by estimating stent patency and patient survival rates. MATERIALS AND METHODS: Thirteen patients with common bile duct strictures (nonhilar) caused by malignant disease were treated by placement of 13 nitinol stents. The stents used include a flared section in the proximal portion (12 mm in diameter and 10 mm in length) and a section in the remnant portion that is fully covered with high-elasticity polyurethane, with an unconstrained diameter of 10 mm and a total length of 50-80 mm. Patient survival and stent patency rates were calculated with use of Kaplan-Meier survival analysis. The follow-up bilirubin and serum amylase and lipase levels were calculated, and the differences in means were evaluated with use of a Wilcoxon signed-rank test. The average follow-up duration was 22.9 weeks (range, 8-56 weeks). RESULTS: Placement was successful in all cases. The 30-day mortality rate was 0%. The survival rates were 38% and 24% at 20 and 50 weeks, respectively. Seventy-seven percent of study patients had adequate palliative drainage during their the remainder of their lives. The stent patency rates were 71% and 48% at 20 and 50 weeks, respectively. Three patients (23%) presented with stent occlusion requiring repeat intervention. There were no procedure-related complications such as proximal or distal migration. No complications occurred other than stent occlusion. One patient's stent was removed under endoscopic guidance 15 weeks after its insertion. Bilirubin levels had significantly decreased 1 week after stent insertion (P <.001). CONCLUSION: Preliminary results suggest that placement of a flared polyurethane-covered self-expandable nitinol stent is feasible and effective in achieving biliary drainage. The stents do not migrate, but there is tumor ingrowth into the flared portion of the stent. Treatment of a larger group of patients will be mandatory to validate these long-term results.

Adult↗
PubMedDate not supplied

Fluoroscopically guided feeding tube insertion for relief of postoperative gastrointestinal anastomotic obstruction and leakage.

PURPOSE: To evaluate the feasibility and effectiveness of feeding tube insertion and enteral feeding for the treatment of postoperative gastrointestinal anastomotic obstruction and leakage. MATERIALS AND METHODS: From June 1999 to June 2002, thirty-four cases of postoperative gastrointestinal anastomotic obstruction and leakage after surgery for gastric carcinoma were treated by insertion of a feeding tube under fluoroscopic guidance. Twenty-one patients were male and 13 were female. The patients' ages ranged from 39 to 74 years (mean age: 61 years). All the patients experienced vomiting, and 15 patients had anastomotic site or duodenal stump leakage. We evaluated the feasibility of feeding tube insertion for enteral feeding to improve the obstruction and facilitate leakage site closure, and the patients' nutritional benefit was also evaluated by checking the serum albumin level between pre- and post-enteral feeding via the feeding tube. RESULTS: Thirty-two patients (94%) were successfully managed by feeding tube insertion, but the remaining two were not managed, and this was due to severe angulations at the anastomotic site. The procedure times for feeding tube insertion ranged from 15 to 60 minutes (mean time: 45 minutes). Twenty-eight patients experienced symptomatic relief of gastrointestinal obstruction, and they were able to resume a normal regular diet after feeding tube removal. Three patients underwent stent insertion due to recurrent symptoms, and one patient underwent jejunostomy feeding due to the presence of a persistent leakage site. Eleven patients achieved leakage site closure after enteral feeding via a feeding tube. The serum albumin level was significant, increased from pre-enteral feeding (2.65 +/- 0.37 g/dL) to the post-enteral feeding (3.64 +/- 0.58 g/dL) via the feeding tube (p < 0.001). The duration of follow-up ranged from one to 53 months (mean: 23 months). CONCLUSION: The insertion of a feeding tube for enteral feeding under fluoroscopic guidance is safe, and it provides effective relief from gastrointestinal anastomotic site obstruction and leakage after gastric surgery. Moreover, our findings indicate that feeding tube insertion for enteral feeding may be used as the primary procedure to treat postoperative anastomotic obstruction and leakage.

Adult↗
PubMedDate not supplied

Ruptures of the medial head of the gastrocnemius ("tennis leg"): clinical outcome and compression effect.

UNLABELLED: The purpose of this study is to describe the clinical outcome of conservative treatment in patients with rupture of the medial head of the gastrocnemius ("tennis leg") occurring during exercise and training and the effect of the compression treatment. MATERIALS AND METHODS: Thirty patients (conservative treatment=15; compression treatment=15), aged 30-45 years, with clinically suspected rupture of the medial head of the gastrocnemius occurring during exercise and training were referred for ultrasonography (US) examination. All patients underwent US of the affected and contralateral asymptomatic limb. Follow-up clinical evaluation and US imaging of all patients each were performed at 1-week intervals during the month after injury and at 2-week intervals during the following 6 months. US findings were analyzed with respect to the integrity of the musculotendinous junctions of the gastrocnemius, the presence of a fluid collection, and the union time of the medial head of the gastrocnemius with the soleus muscle. In addition, we analyzed the clinical outcome of the compression treatment. RESULTS: Of the 30 patients who had an initial US examination after their injury, partial rupture of the medial head of the gastrocnemius muscle was identified in 11 patients (36.7%); the remaining 19 patients were diagnosed with complete rupture. Fluid collection between the medial head of the gastrocnemius and the soleus muscle was identified in 25 patients (83.3%). First union of the medial head of the gastrocnemius with the soleus muscle in the compressive group was significantly rapid than that of the conservative group (4.25 vs. 3.25 weeks; P=.02). Fluid collection between the two muscles after 1 month in the compressive group was significantly smaller than that in the conservative group (8.9 vs. 4.5 mm; P=.01). CONCLUSIONS: Early compressive treatment in patients with rupture of the medial head of the gastrocnemius decreases the hemorrhage amount and can be possible for early ambulation.

Adult↗
PubMedDate not supplied

Focal eosinophilic infiltration of the liver mimicking hepatocellular carcinoma: case reports.

Focal eosinophilic infiltration is a rare disease entity that in patients with malignancies may mimic malignant hepatic nodules. We describe two cases in which focal eosinophilic infiltration of the liver, as well as primary liver cancer, occurred. In these patients, imaging findings similar to those observed in hepatocellular carcinoma (HCC) were noted: Enhancement at dynamic magnetic resonance (MR) imaging substantially increased perfusion at computed tomography during hepatic arteriography (CTHA) and a perfusion defect at computed tomography during arterial portography (CTAP).

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Detection of small hypervascular hepatocellular carcinomas in cirrhotic patients: comparison of superparamagnetic iron oxide-enhanced MR imaging with dual-phase spiral CT.

OBJECTIVE: To compare the performance of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) maging at 1.5T and dual-phase spiral computed tomography (CT) for the depiction of small hypervascular hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: Forty-three patients with 70 small nodular HCCs (5-20 mm; mean, 13.7 mm) were examined. Diagnosis was based on the results of surgical biopsy in 22 patients and by the combined assessment of MR imaging, lipiodol CT, alpha feto-protein levels, and angiographic findings in 21. MR imaging consisted of respiratory-triggered turbo spin-echo T2-weighted imaging, T1-weighted fast low-angle shot, and T2* -weighted fast imaging with steady-state precession imaging before and after SPIO enhancement. CT imaging was performed with 5-mm collimation and 1:1.4 pitch, and began 30 and 65 secs after the injection of 150 mL of contrast medium at a rate of 3 mL/sec. Two blinded observers reviewed all images independently on a segment-by-segment basis. Diagnostic accuracy was evaluated using receiver operating characteristics(ROC) analysis. RESULTS: The mean areas (Az) under the ROC curves were 0.85 for SPIOenhanced MR imaging and 0.79 for dual-phase spiral CT (p <.05). The mean sensitivity of SPIO-enhanced MR imaging was significantly higher than that of CT (p <.05), i.e. 70.6% for MR imaging and 58.1% for CT. MR imaging had higher false-positive rates than dual-phase spiral CT, but the difference was not statistically significant (3.7% vs 3.3%) (p >.05). CONCLUSION: SPIO-enhanced MR imaging is more sensitive than dual-phase spiral CT for the depiction of small hypervascular hepatocellular carcinomas.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Diagnosis and follow-up US evaluation of ruptures of the medial head of the gastrocnemius ("tennis leg").

OBJECTIVE: The purpose of this study was to demonstrate the ultrasonographic (US) findings of rupture and the healing process of the medial head of the gastrocnemius ("Tennis Leg"). MATERIALS AND METHODS: Twenty-two patients (age range: 30 to 45 years) with clinically suspected ruptures of the medial head of the gastrocnemius were referred to us for US examination. All the patients underwent US of the affected limb and the contralateral asymptomatic limb. Follow-up clinical evaluation and US imaging of all patients were performed at two-week intervals during the month after injury and at one-month intervals during the following six months. RESULTS: Of the 22 patients who had an initial US examination after their injury, partial rupture of the medial head of the gastrocnemius muscle was identified in seven patients (31.8%); the remaining 15 patients were diagnosed with complete rupture. Fluid collection between the medial head of the gastrocnemius and the soleus muscle was identified in 20 patients (90.9%). The thickness of the fluid collection, including the hematoma in the patients with complete rupture (mean: 9.7 mm), was significantly greater than that seen in the patients with partial tear (mean: 6.8 mm) (p < 0.01). The primary union of the medial head of the gastrocnemius with the soleus muscle in all the patients with muscle rupture and fluid collection was recognized via the hypoechoic tissue after four weeks. CONCLUSION: Ultrasonography is a useful imaging modality for the diagnosis and follow-up examination for the patients suffering with rupture of the medial head of the gastrocnemius.

Adult↗
PubMedDate not supplied

Treatment of gastrojejunal anastomotic leak with a covered metallic stent.

Although the incidence rates of anastomotic leaks after radical gastrectomy in a patient with gastric cancer are generally low, when the complication ensues, morbidity and mortality rates rise, varying between 18% and 30%. We used self-expandable, covered metallic stent to occlude the leakage site in a patient with recurrent postoperative anastomotic leaks. The deployment of the covered stent was successful, and immediate leak occlusion was obtained after the procedure. During follow-up, the patient had unrecognized passage of the stent per rectum and showed no anastomotic leak on upper gastrointestinal series. We suggest that implementation of covered metallic stent should be considered as a valuable, alternative therapeutic option for the treatment of intractable postoperative anastomotic leak after radical gastrectomy.

Aged↗