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Biomedical subjects

S W Choo

Publications and source records attributed to S W Choo.

At least 19 recordsLinked to original sources
PubMed2006

Hepatic intra-arterial injection of 3-bromopyruvate in rabbit VX2 tumor.

PURPOSE: To evaluate the antitumoral effects of an intra-arterial injection of 3-bromopyruvate (3-BrPA) on liver VX2 tumor in rabbits. MATERIAL AND METHODS: Twenty rabbits with surgically implanted liver VX2 tumors were used. The rabbits were divided into three groups: a control, a saline, and a 3-BrPA group. Four rabbits were not treated at all, and they served as the control group. The saline group (n = 6) received only intra-arterial saline injection. The 3-BrPA group (n = 10) received an intra-arterial injection of 3-bromopyruvate through the hepatic artery. The delivered amounts of 3-bromopyruvate were as follows: 25 ml of 0.5 mM in six rabbits, 25 ml of 1.0 mM in two rabbits, and 25 ml of 2.0 mM in two rabbits. Four days after intra-arterial injection, the rabbits were sacrificed and histopathologic analysis of the explanted livers was performed with comparison of the tumor necrosis ratio (a percentage of the necrotic area versus the entire tumorous area) in each group. RESULTS: The mean tumor necrosis ratio was 12.5+/-4.2%, 44.8+/-24.7%, and 49.4+/-14.3% in the control, saline, and 3-BrPA groups, respectively. Between the control and the saline group, and between the control and the 3-BrPA group the mean tumor necrosis ratio appeared to be significantly different (P<0.05). However, there was no statistical difference in the mean tumor necrosis ratio between the saline and the 3-BrPA group (P = 0.416). CONCLUSION: A single session of intra-arterial injection of 3-BrPA showed no better results in terms of tumor necrosis than that of saline injection in a rabbit VX2 tumor model.

Animals↗
PubMed2001

Mediastinal interfaces and lines in children: radiographic-CT correlation.

BACKGROUND: Various mediastinal interfaces and lines are well known in adults, but not fully understood in children. OBJECTIVE: To review the mediastinal interfaces and lines on plain radiographs in the paediatric age group with CT correlation. MATERIALS AND METHODS: Soft copies of 195 sets of CT examinations and concurrent chest radiographs in 180 paediatric patients (age 1 month to 15 years) were retrospectively reviewed. The frequency of visualisation and the anatomical basis of the mediastinal interfaces and lines were assessed. The evaluated mediastinal interfaces and lines were superior vena cava interface, descending aorta interface, left paraspinal interface, azygoesophageal recess interface, right paratracheal stripe, anterior junction line and posterior junction line. RESULTS: Chest radiographs showed the SVC interface in 161, the descending aorta interface in 155, the left paraspinal interface in 98, the azygoesophageal recess in 94, the right paratracheal stripe in 53, the anterior junction line in 15 and the posterior junction line in 10. Non-visualisation of mediastinal interfaces and lines on plain radiographs was explained by normal anatomical difference compared with the adult and underlying intrathoracic abnormalities when they were correlated with CT. The frequency of visualisation of the SVC interface, descending aortic interface, left paraspinal interface and azygoesophageal recess fluctuated with age, while the frequency of the right paratracheal stripe, anterior junction line and posterior junction line increased with age. CONCLUSIONS: Awareness of the frequency of visualisation and the anatomical basis of the mediastinal interfaces and lines in paediatric patients may be helpful for interpretation of chest radiographs.

Adolescent↗
PubMed2001

Malignant esophagogastric junction obstruction: palliative treatment with an antireflux valve stent.

The authors assessed the efficacy of an antireflux valve stent in the palliation of malignant esophagogastric junction (EGJ) obstruction after in vitro testing of the stent. Seventeen patients with inoperable malignant EGJ obstruction were treated. Antireflux valves, made of three polyurethane leaflets, were attached to the distal part of the stent to prevent reflux. When the flow rate of normal saline was 100 mL/sec in the forward direction, the valve fully opened at a pressure of 10 mm Hg. When the flow rate of normal saline was 0.35 mL/sec in the backward direction, the valve nearly completely closed at a pressure of 10 mm Hg. Stent placement was successful in all patients without complications. The median dysphagia score decreased significantly, from 3.0 (dysphagia to liquids) to 1.0 (dysphagia to normal solid food) (P < .0005). No patients experienced reflux symptoms. There was one case of stent migration. A valve stent that can prevent major reflux is an effective device for the palliation of malignant EGJ obstruction.

Aged↗
PubMed2001

Malignant obstruction of gastric outlet and duodenum: palliation with flexible covered metallic stents.

PURPOSE: To assess the usefulness of flexible covered metallic stents in the palliation of malignant obstruction of the gastric outlet and duodenum. MATERIALS AND METHODS: Twenty-four consecutive patients with malignant obstruction of the gastric outlet (n = 22) or duodenum (n = 2) underwent palliative treatment with self-expandable flexible covered metallic stents. Fourteen patients had advanced gastric carcinoma at the antrum and/or pylorus, and eight had obstruction at the anastomosis site of previous gastrojejunostomy. Complications and clinical status were investigated during the study period. RESULTS: The technical success rate was 75% (18 of 24 patients). Twenty-one stents were placed in 18 patients by using an introducer 6 (n = 7) or 8 mm (n = 14) in diameter. The mean follow-up period was 3.4 months (range, 1 week to 9 months). Symptoms improved in 12 (67%) patients after the procedure. There was no change in symptoms in five and a decrease in one. Twelve patients died during the follow-up period (mean survival, 4.3 months). The complication rate was 25% (six of 24 patients), including stent migration (n = 5) and fracture (n = 3). CONCLUSION: Flexible covered metallic stent placement can be useful for palliation in patients with malignant obstruction of the gastric outlet or duodenum.

Adult↗
PubMed2000

Semiinvasive pulmonary aspergillosis: CT and pathologic findings in six patients.

OBJECTIVE: We describe the chest CT and pathologic findings of semiinvasive pulmonary aspergillosis in six patients. CONCLUSION: Semiinvasive pulmonary aspergillosis should be considered in the mildly immunocompromised patient with CT findings that reveal persistent parenchymal abnormalities. Patterns include consolidation and mass.

Adult↗
PubMed1999

Intramuscular vascular malformations of an extremity: findings on MR imaging and pathologic correlation.

OBJECTIVE: To analyze the findings of intramuscular vascular malformations of an extremity on MR imaging and to correlate these findings with histopathologic examination. DESIGN AND PATIENTS: The findings on MR imaging and the medical records of 14 patients with an intramuscular vascular malformation of the extremity were retrospectively studied. All patients underwent surgical excision. Diagnoses were based on the results of pathologic examination. Findings on MR imaging were noted and correlated with the histopathologic findings. RESULTS: Intramuscular vascular malformations of an extremity showed multi-septate, honeycomb, or mixed appearance on MR imaging. Multi-septate areas correlated with dilated and communicating vascular spaces with flattened endothelium. Honeycomb areas corresponded to vascular spaces with inconspicuous small lumina and thickened vascular walls. Areas of increased signal intensity on T2-weighted images were found in all intramuscular vascular malformations. Infiltrative margins were more commonly seen in intramuscular lymphaticovenous malformations. Adherence to neurovascular structures and orientation of the lesion along the long axis of the affected muscle were more commonly seen in intramuscular venous malformations. CONCLUSIONS: Intramuscular vascular malformations showed either a multi-septate, honeycomb, or mixed appearance, reflecting the size of the vascular spaces and the thickness of the smooth muscles of the vessel walls. Prediction of the subtype of an intramuscular vascular malformation of an extremity on MR imaging seems to be difficult, although there are associated findings that may be helpful in the differential diagnosis of each subtype.

Adolescent↗
PubMed1999

Upper gastrointestinal tract malignant obstruction: initial results of palliation with a flexible covered stent.

The authors treated 21 patients with inoperable upper gastrointestinal tract malignant obstruction from the esophagus to the duodenum by means of intubation with a flexible covered stent with fluoroscopic guidance. Stent placement was successful and relief of dysphagia was immediate in 18 (86%) patients, without serious complication. The average dysphagia score decreased from 2.6 (dysphagia to liquids) to 1.0 (dysphagia to normal solid food). Placement of a flexible covered stent provides easy, safe, and effective palliation of upper gastrointestinal malignant obstruction.

Adult↗
PubMed1999

Splanchnic arterial stenosis or occlusion: diagnosis at Doppler US.

PURPOSE: To determine the diagnostic accuracy of Doppler ultrasonography (US) in the detection of high-grade stenosis or occlusion of the celiac artery (CA) and superior mesenteric artery (SMA) and validate the previously reported Doppler US criteria. MATERIALS AND METHODS: During a recent 36-month period, 82 patients were prospectively examined with Doppler US of the splanchnic arteries and with lateral abdominal aortography, regardless of their abdominal symptoms. The previously reported diagnostic criteria with the fasting peak systolic velocity measurement were prospectively used in all patients. The results of Doppler US were compared with those of lateral aortography. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of Doppler US for the detection of 70% or greater CA stenosis or occlusion were 100%, 87%, 57%, 100%, and 89%, respectively; for 70% or greater SMA stenosis or occlusion, these values were 100%, 98%, 93%, 100%, and 99%, respectively. CONCLUSION: Owing to its high accuracy in the diagnosis of high-grade splanchnic arterial stenosis or occlusion, Doppler US can be used as a screening method to help detect CA or SMA stenosis or occlusion and can reduce the use of unnecessary, invasive angiography.

Aged↗
PubMed1998

Malignant colorectal obstruction: treatment with a flexible covered stent.

PURPOSE: To evaluate the usefulness of flexible covered stents for treatment of acute colorectal obstruction secondary to malignant colorectal carcinoma. MATERIALS AND METHODS: Twenty patients with acute colorectal obstruction secondary to malignant colorectal carcinoma were treated by means of intubation of a flexible stent with fluoroscopic guidance with occasional endoscopic assistance. Two types of stents were placed (type 1, completely covered, type 2, two-thirds of proximal part uncovered). Of 15 patients with primary colorectal carcinoma, 12 underwent placement of a stent for presurgical decompression of colorectal obstruction; three, for palliative decompression. In three patients with rectosigmoid seeding from advanced gastric carcinoma and two patients with recurrent colonic carcinoma, stents were placed for palliative decompression. RESULTS: Stent placement was successful in 18 (90%) of 20 patients. Symptoms of obstruction resolved within 24 hours in 15 (75%) patients. Eight patients underwent elective single-stage surgery without complications 5-7 days after stent placement. Two patients underwent tumor resection and colostomy. In eight patients, stents provided palliative decompression of the colon. Type 1 stents migrated in four (50%) of eight patients; type 2 stents were used thereafter. CONCLUSION: Flexible stents effectively relieved acute colonic obstruction secondary to malignant rectosigmoid neoplasm. Stent placement allowed patients to undergo single-stage surgery in most cases and provided palliative decompression in cases of inoperable or disseminated disease.

Acute Disease↗
PubMed1997

MR imaging of segmental renal infarction: an experimental study.

An experimental study was performed in 12 rabbits to evaluate the magnetic resonance (MR) imaging findings of segmental renal infarction. Three or four MR examinations were performed at 6 h, 1 day, 3 days, 1 week, 2 weeks, and 4 weeks following the ligation of segmental artery of the left kidney. The signal intensities of the infarcted area on both T1- and T2-weighted (T1W and T2W, respectively) images were lower than those of the non-affected area in the 6 h group, and pathological examination showed mild interstitial oedema and haemorrhage. The signal intensities of the lesion became higher on T1W images and higher or mixed on T2W scans in the 1 day group, in which the pathological findings were intense interstitial haemorrhage, interstitial oedema, and early coagulative necrosis. The signal intensities of the lesion on both pulse sequences were also higher in the 3 day and 1 week groups in which pathological examination showed progressive coagulative necrosis. The signal intensities of the lesions in the 2 and 4 week groups were lower on both pulse sequences, and the pathological finding was organizing fibrosis. Post-contrast T1W images demonstrated well the extent of the infarction in all but two cases, in which the signal intensities of the lesions were higher on pre-contrast T1W scans.

Animals↗
PubMed1996

Neofissure after lobectomy of the right lung: radiographic and CT findings.

PURPOSE: To document the postlobectomy radiographic and computed tomographic (CT) appearance of neofissures of the right lung. MATERIALS AND METHODS: Chest radiographs and CT scans from 25 patients who had undergone right lobectomy were assessed by two chest radiologists, and decisions on the findings were reached by consensus. Analyses included orientation of the neofissure and lobar reorientation of the remaining lobes. RESULTS: Neofissure location after right upper lobectomy (n = 13) was superior and anterior compared with the location of the left major fissure on both lateral radiographs and CT scans. After right middle lobectomy (n = 4), the neofissure had less vertical orientation than the left major fissure (the highest posterior portion was lower and the lowest anterior portion was higher than the left major fissure) on both lateral radiographs and CT scans. After right lower lobectomy (n = 8), two types of lobar reorientation and, accordingly, two types of neofissure were observed in the right lower lung zone (posteriorly and anteriorly high, respectively, on lateral radiographs). CONCLUSION: Analyses of neofissures on lateral radiographs and CT scans enable differentiation among various kinds of lobectomy.

Adult↗
PubMed1996

Early graft dysfunction due to renal vein compression.

We here report on an unusual case of early renal transplant dysfunction due to renal vein compression. Graft function was initially good but oliguria and massive hematuria developed on the 3rd day after transplantation. Duplex sonography showed turbulent blood flow of the renal vein, and renal venography confirmed renal vein compression. Exploratory laparotomy was performed and diuresis was initiated just after nephropexy. In conclusion, renal vein compression is a rare complication but should be included in the possible causes of early renal transplant dysfunction since this can be simply diagnosed by duplex sonography and is easily remedied by nephropexy.

Adult↗
PubMed1995

Congenital fistula from ectopic accessory parotid gland: diagnosis with CT sialography and CT fistulography.

We report a case of congenital fistula from ectopic accessory parotid gland to the cheek demonstrated by CT sialography and CT fistulography. The right parotid gland was abnormally located lateral to masseter muscle. The fistula was arising from an ectopic accessory parotid gland with ectopic duct positioned anterior to masseter muscle. CT sialography and CT fistulography were very helpful in the diagnosis and surgical planning.

Cheek↗
PubMedDate not supplied

Colitis in Behçet's disease: characteristics on double-contrast barium enema examination in 20 patients.

We performed a retrospective review of double-contrast barium enema examinations of 20 patients with clinically proven Behçet's colitis. Main lesion was ovoid or geographic ulcers with a mean diameter of 2.7 cm. The number of ulcers was single in 15 cases and multiple in five. On six resected specimens, ulcers involved submucosa in three, muscle layer in one, and serosa in two cases with an undermining tendency and transmural inflammation. Aphthous ulcers were present in three cases. Neither perforation nor fistula was demonstrated. In all 20 patients, the ulcer was localized in the ileocecal area, with extension to the ascending colon in seven. Skip lesions were observed in the transverse colon and descending colon in three cases. Destruction of surrounding mucosa resulted in cecal contraction in 19 cases, widening of the ileocecal valve in 19, and fold thickening in the terminal ileum in 12. Six cases (30%) manifested as ileocecal mass accompanied by ulcer, fold thickening, and adjacent mucosal deformity. The appendix was visualized in only three (20%) of the 15 patients with no history of appendectomy. On follow-up study of 15 cases, the ulcers disappeared or decreased in size in 13 cases (86%) and the mucosal deformity was not improved in all cases. On the basis of our results, we believe that the characteristic findings of colitis in Behçet's disease in barium enema examination are ovoid or geographic, relatively large, and deep ulcerations with persistent surrounding deformity which tend to localize in the ileocecal area.

Adolescent↗
PubMedDate not supplied

Transjugular liver biopsy: modified Ross transseptal needle versus quick-core biopsy needle.

BACKGROUND: We evaluated the differences in sample adequacy and safety between a transseptal needle and Quick-core biopsy needle for transjugular liver biopsy. METHODS: Eighteen consecutive patients who had a bleeding diatheses and/or ascites underwent transjugular liver biopsy using a transseptal needle (11 patients) and Quick-core biopsy needle (seven patients). The length of the specimens was measured before fixation. A pathologist reviewed histologic slides for sample adequacy and pathologic diagnoses. Clinical records were reviewed for complication. RESULTS: In all patients, liver biopsy was successful. A total of 45 specimens were obtained, with an average of 2.5 passes per patient. The length of specimen was significantly longer with the Quick-core biopsy needle than with the transseptal needle (p<0.05). Biopsied tissue was fragmented in 17 of 25 specimens with the transseptal needle but not fragmented in any specimen with the Quick-core biopsy needle. All specimens were determined to be adequate except one with the transseptal needle. There was no early or delayed complication in any patient. CONCLUSION: Transjugular liver biopsy is a safe and effective procedure without any significant difference in complication and adequacy when using a transseptal needle or Quick-core biopsy needle. Larger specimens can be obtained without tissue fragmentation with the Quick-core biopsy needle.

Adolescent↗
PubMedDate not supplied

Iodized oil retention due to postbiopsy arterioportal shunt: a false positive lesion in the investigation of hepatocellular carcinoma.

BACKGROUND: Iodized-oil computed tomography (CT) is useful for the diagnosis of hepatocellular carcinoma, but there may be false-positive results in patients who have undergone some percutaneous transhepatic interventional procedures. The purpose of the present study was to verify the correlation between subsegmental hepatic parenchymal retention of iodized oil on CT and the arterioportal shunt caused by liver biopsy. METHODS: Iodized-oil CT scans were reviewed in 24 patients with hepatic tumors who had liver biopsy and subsequent iodized oil chemoembolization. Iodized oil chemoembolization was performed shortly after biopsy (1-10 days; mean = 2.6 days). The results were correlated with hepatic arteriography, with a special emphasis on the presence of hepatic arterioportal shunt. RESULTS: Wedge-shaped subsegmental retention of iodized oil along or adjacent to the biopsy needle path was observed in iodized-oil CT in 17 of the 24 patients. In three patients, there was subsegmental enhancement on prebiopsy helical dynamic liver CT at the same area of iodized oil retention, and therefore iodized oil retention was considered to be due to hepatocellular carcinoma. In the remaining 13 (54%) patients, the peripheral iodized oil retention was considered to be due to biopsy-induced arterioportal shunt. In all these patients, arterioportal shunt was confirmed by hepatic arteriography. CONCLUSION: Wedge-shaped hepatic parenchymal retention of iodized oil is commonly observed in iodized-oil CT due to biopsy-induced arterioportal shunt, and this appearance should not be confused with a hepatocellular carcinoma.

Arteriovenous Fistula↗