Biomedical subjects

Chung-Hwan Baek

Publications and source records attributed to Chung-Hwan Baek.

15 recordsLinked to original sources

PubMed2007

Use of integrated 18F-FDG PET/CT to improve the accuracy of initial cervical nodal evaluation in patients with head and neck squamous cell carcinoma.

BACKGROUND: We investigated the accuracy of performing cervical nodal evaluation with using integrated (18)F-fluoro deoxyglucose positron emission tomography (PET)/CT for squamous cell carcinoma (SCC) of the head and neck as compared with using PET and contrast-enhanced CT (CECT) alone. METHODS: The presence of metastatic lymphadenopathy in each cervical nodal group (level I-VI) and the nodal (N) classification of 47 patients with SCC of the head and neck were determined by using PET, CECT, and PET/CT, respectively, and the results were verified according to the histopathologic findings. RESULTS: Among the 91 foci that had abnormal uptake on PET, the combined PET/CT images provided additional information over PET for the anatomical localization and lesion characterization of 18 sites (19.8%) in 17 patients (36.2%). PET/CT also showed the best results among the three imaging modalities for the sensitivity, specificity, and accuracy (91.8, 98.9, and 97.1%, respectively) for predicting metastatic nodes on a level-by-level analysis, and PET/CT had a higher accuracy (85.1%) for the pathologic nodal classification over the clinical examinations (68.1%) or PET (70.2%). CONCLUSIONS: Combined PET/CT images are more accurate than the PET or CECT images alone for conducting cervical node evaluation in the patients suffering with head and neck SCC.

Aged↗

PubMed2006

New modification of the mandibulotomy approach without lip splitting.

BACKGROUND: A lower lip-splitting incision has traditionally been performed with different types of mandibulotomy approaches for obtaining wide access to oral and oropharyngeal cancers. However, lip splitting can be associated with unfavorable aesthetic results. We describe our new modification of a traditional mandibulotomy approach without lip splitting to avoid these morbidities. This is a case series in a tertiary referral center. METHODS: The primary tumor site was the oropharynx in four cases, the oral cavity in two cases, and the parapharynx in one case. Each case was assessed for TNM staging, perioperative complications, status of the resection margins, tumor recurrence, and the aesthetic and functional results of the lower lip. RESULTS: All the tumors were safely removed by means of our modified non-lip-splitting mandibulotomy approach through the combined intraoral and transcervical routes with adequate resection margins. There were no troublesome difficulties in reconstruction of the surgical defects with various major flaps. The cosmetic results were excellent with intact lip function. CONCLUSION: We believe this new modified non-lip-splitting mandibulotomy approach could replace the conventional mandibulotomy approach for some selected malignant lesions, with excellent cosmetic and functional results of the lower lip.

Adolescent↗

PubMed2006

Treatment for extracranial arteriovenous malformations of the head and neck.

CONCLUSIONS: For extracranial arteriovenous malformations of the head and neck (HNAVMs), in which the nidus was accessible via the percutaneous route, ethanol sclerotherapy was a feasible and safe first-line treatment, although successful outcomes were obtained for only about half of the subjects. For other HNAVMs, surgical excision with embolization may be the best choice of treatment. OBJECTIVE: To suggest a treatment protocol for patients with HNAVMs by comparing the treatment outcomes and complications of ethanol sclerotherapy with those of surgical excision combined with embolization. MATERIAL AND METHODS: Twenty patients who had been diagnosed with HNAVM and treated between 1995 and 2002 were retrospectively reviewed. Ethanol sclerotherapy, surgical excision and embolization were used as treatments, either alone or in various combinations. The treatment outcomes and complications with the different modalities were analyzed. RESULTS: Ethanol sclerotherapy was used for 12 cases, with a success rate of 50.0% and a permanent complication rate of 8.3%. Surgical excision combined with embolization was used for 13 patients. Although all patients achieved successful resolution of their HNAVM after surgical excision, 15.4% suffered from permanent complications. In total, 16/20 patients (80.0%) eventually achieved a > or = 75% reduction in the size of their lesions.

Adolescent↗

PubMed2006

Characteristics of tissue-engineered cartilage on macroporous biodegradable PLGA scaffold.

BACKGROUND: The purpose of this study was to establish in vivo culture of chondrocytes on biodegradable, poly-D,L-lactic-co-glycolic acid (PLGA) scaffolds and to analyze the characteristics of the reconstructed cartilage. METHODS: In vitro cultured chondrocytes that were grown on a polyhydroxyethyl methacrylate (poly-HEMA) coated dish were seeded onto the PLGA scaffolds to make a cell-polymer construct before implantation. One cell scaffold construct was carefully implanted in the subcutaneous pocket of a nude mouse and another cell-free scaffold was implanted in the opposite side of the same nude mouse as the control. Morphologic, biochemical, and immunohistochemical characteristics of cells cultured within the PLGA constructs were examined after 8 weeks and 16 weeks of harvesting in the nude mouse. RESULTS: New cartilage began to be generated in the period of 8 weeks and the neocartilage formation was accomplished in 4 months with the exact dimensions of the original scaffold in this in vivo study. All the explants showed the irregular shape of viable chondrocytes within normal lacunae and a mature cartilaginous matrix, and they positively immunostained for collagen type II. CONCLUSION: The new tissue-engineered cartilage in vivo on PLGA scaffolds displayed the biochemical characteristics of cartilage tissue, and it showed chondrocyte-specific phenotypes and morphology that were similar to the native cartilage.

Absorbable Implants↗

PubMed2006

Can [18F]-fluorodeoxyglucose standardized uptake values of PET imaging predict pathologic extrathyroid invasion of thyroid papillary microcarcinomas?

OBJECTIVE: To evaluate the hypothesis that the [F]-fluorodeoxyglucose (FDG) standardized uptake values (SUVs) of positron emission tomographic (PET) imaging can predict pathologic extrathyroid invasion of thyroid papillary microcarcinomas (TPMC) DESIGN: Prospective clinical study. METHOD: From 2004 to 2005, 44 consecutive patients with TPMC (< or =1 cm), confirmed by ultrasonography and aspiration cytology, had FDG PET scans performed. Among them, 66 tumor foci in 41 patients were confirmed to be of less than 1 cm in diameter by the final surgical pathology report. According to the microcarcinoma tumor focus, prediction of pathologic extrathyroid invasion, by clinical variables including sonographic findings and SUVs from PET imaging, was evaluated by the univariate and multivariate logistic regression analysis. RESULTS: : Univariate analysis showed that the tumor site attached to the thyroid capsule and the SUVs of PET imaging could predict pathologic extrathyroid invasion. However, the tumor site attached to thyroid capsule and an age older than 45 were significant predictors by multivariate analysis (P = .001 and P = .036). SUVs from PET imaging were only correlated with the size of tumor (P < 0.001). CONCLUSION: The SUVs from FDG PET imaging alone cannot predict the pathologic extrathyroid invasion in patients with TPMC. However, the ultrasonographic findings, such as tumor site, provide better information about the extrathyroid invasion of TPMC tumor foci.

Adult↗

PubMed2006

Integrated 18F-FDG PET/CT for the initial evaluation of cervical node level of patients with papillary thyroid carcinoma: comparison with ultrasound and contrast-enhanced CT.

OBJECTIVE: To compare the diagnostic accuracy of integrated 18F-fluorodeoxyglucose PET/CT with ultrasonography (US) and contrast enhanced CT (CECT) alone in the initial evaluation of cervical lymph node levels of patients with papillary thyroid carcinoma. PATIENTS AND MEASUREMENTS: From July 2004 to March 2005, 26 consecutive patients with papillary thyroid carcinoma, confirmed by aspiration cytology analysis, underwent US, CECT and PET/CT. The sensitivity, specificity and diagnostic accuracy of the US, CECT and PET/CT studies for the final status of 312 cervical node levels (levels I-V: 260, level VI: 52) were compared by employing a generalized estimating equation test. The final status of cervical node levels was determined by the surgical pathology and follow-up data. RESULTS: At all lymph node levels (levels I-VI), PET/CT showed a sensitivity of 30.4%, a specificity of 96.2% and a diagnostic accuracy of 86.9%. The corresponding values for US and CECT were 41.3%, 97.4%, 89.1% (US) and 34.8%, 96.2%, 87.2% (CECT). Considering only the lateral cervical node group (levels I-V), PET/CT showed a sensitivity of 50.0%, a specificity of 97.0% and a diagnostic accuracy of 92.3%. The corresponding values for US and CECT were 53.9%, 97.9%, 93.5% (US) and 42.3%, 96.6%, 91.2% (CECT). The diagnostic results for US, CECT and PET/CT upon initial evaluation of the cervical lymph nodes did not differ significantly on a level-by-level basis. CONCLUSION: Our preliminary results suggest that integrated PET/CT does not provide any additional benefit when compared to US and CECT for the initial evaluation of cervical node levels in patients with papillary thyroid carcinoma.

Adolescent↗

PubMed2006

Sentinel lymph node radiolocalization with 99mTc filtered tin colloid in clinically node-negative squamous cell carcinomas of the oral cavity.

The objective of this study was to evaluate the feasibility of sentinel lymph node biopsy by using a radiotracer lymphatic mapping technique in patients with squamous cell carcinoma of the oral cavity, and the diagnostic value of this technique. We studied twenty patients with previously untreated squamous cell carcinomas of the oral cavity and N0 necks. After the peritumoral injection of 99mTc filtered tin colloid preoperatively, lymphoscintigraphy and intraoperative mapping using a gamma detector were performed to localize sentinel nodes. An open biopsy of the sentinel node was followed by complete neck dissection. We identified the sentinel nodes in 19 of 20 patients (95.0%) by lymphoscintigraphy and in all (100%) by intraoperative gamma detector. In all cases, the status of the sentinel node accurately predicted the pathologic status of the neck with the false negative rate being 0%. The negative predictive value for the absence of cervical metastases was 100%. In conclusion, our radiolocalization technique of sentinel nodes using 99mTc filtered tin colloid in N0 squamous cell carcinomas of the oral cavity is technically feasible and appears to accurately predict the presence of the occult metastatic disease.

Adult↗

PubMed2006

Focal thyroid lesions incidentally identified by integrated 18F-FDG PET/CT: clinical significance and improved characterization.

UNLABELLED: In this retrospective study, we investigated whether the (18)F-FDG uptake pattern and CT findings improved the accuracy over the standardized uptake value (SUV) for differentiating benign from malignant focal thyroid lesions incidentally found on (18)F-FDG PET/CT. We also defined the prevalence of these lesions and their risk for cancer. METHODS: (18)F-FDG PET/CT was performed on 1,763 subjects without a previous history of thyroid cancer from May 2003 to June 2004. Two nuclear medicine physicians and 1 radiologist interpreted PET/CT images, concentrating on the presence of focal thyroid lesions, the maximum SUV of the thyroid lesion, the pattern of background thyroid (18)F-FDG uptake, and the CT attenuation pattern of the thyroid lesion. RESULTS: The prevalence of focal thyroid lesions on PET/CT was 4.0% (70/1,763). Diagnostic confirmation was done on 44 subjects by ultrasonography (US)-guided fine-needle aspiration (n = 29) or US with clinical follow-up (n = 15). Among 49 focal thyroid lesions in these 44 subjects, 18 focal thyroid lesions of 17 subjects were histologically proven to be malignant (papillary cancer in 16, metastasis from esophageal cancer in 1, non-Hodgkin's lymphoma in 1). Therefore, the cancer risk of focal thyroid lesions was 36.7% on a lesion-by-lesion basis or 38.6% on a subject-by-subject basis. The maximum SUV of malignant thyroid lesions was significantly higher than that of benign lesions (6.7 +/- 5.5 vs. 10.7 +/- 7.8; P < 0.05). When only the maximum SUV was applied to differentiate benign from malignant focal thyroid lesions for the receiver-operating-characteristic curve analysis, the area under the curve (AUC) of PET was 0.701. All 16 focal thyroid lesions with very low attenuation or nonlocalization on CT images, or with accompanying diffusely increased thyroid (18)F-FDG uptake, were benign. When those lesions were regarded as benign lesions, irrespective of the maximum SUV, the AUC of PET/CT was significantly improved to 0.878 (P < 0.01). CONCLUSION: Focal thyroid lesions incidentally found on (18)F-FDG PET/CT have a high risk of thyroid malignancy. Image interpretation that includes (18)F-FDG uptake and the CT attenuation pattern, along with the SUV, significantly improves the accuracy of PET/CT for differentiating benign from malignant focal thyroid lesions.

Adult↗

PubMed2005

Improved detection of second primary cancer using integrated [18F] fluorodeoxyglucose positron emission tomography and computed tomography for initial tumor staging.

PURPOSE: This study evaluated prospectively the value of integrated whole-body positron emission tomography and computed tomography (PET/CT) using [18F] fluorodeoxyglucose (FDG) in detecting a second primary cancer at the time of the initial staging in comparison with a conventional staging work-up (CSW). METHODS: The participants were 547 patients diagnosed with cancer who underwent FDG PET/CT imaging for the initial staging. An additional diagnostic evaluation was performed when there were abnormal findings indicative of a second primary cancer on either PET/CT or CSW considering the site and the biologic behavior of the alleged primary tumor. RESULTS: A total of 27 second primary malignant tumors were identified in 26 of the 547 patients (4.8%). FDG PET/CT found 45 lesions indicative of a second primary cancer, of which 24 lesions were proved to be a second primary cancer, seven were clinically unexpected metastases, and 14 lesions were benign. Therefore, sensitivity and positive predictive value of FDG PET/CT in detecting a second primary cancer or an unexpected metastasis were 91% (31 of 34) and 69% (31 of 45), respectively. In contrast, CSW could not identify 16 second primary cancers and one metastatic lesion. CONCLUSION: FDG PET/CT at the time of the initial staging is useful for screening a second primary cancer with a high sensitivity. An additional diagnostic work-up is essential when abnormal findings, which are indicative of a second primary cancer, are obtained on PET/CT images to rule out the presence of either a second primary cancer or an unexpected metastasis.

Aged↗

PubMed2005

Comparison of open dilatational tracheostomy with conventional pediatric tracheostomy in a growing animal model.

OBJECTIVES: To compare the tracheal changes after applying a new open dilatational tracheostomy (ODT) technique with those from a conventional open tracheostomy (COT) with vertical cartilage incision in a growing animal model. STUDY DESIGN: Prospective, experimental investigation in a rabbit model. MATERIALS AND METHODS: Thirteen New Zealand white rabbits as a pediatric model were divided into three groups: six rabbits had COT (n = 6), another six underwent an ODT (n = 6), and one rabbit acted as a control. Each rabbit underwent tracheostomy by assigned procedures on the first day. On day 8, they were decannulated. On day 15, their tracheas were harvested. We examined the gross findings and histologic changes of each tracheal segment at the stomal level. In addition, we analyzed three parameters: the quotient of the stomal and nonstomal segment in sagittal diameter, coronal diameter, and cross-sectional area. RESULTS: The framework of cartilages at the stomal level were more distorted in the COT group. Histologic examination also showed buckling of the anterior tracheal wall, loss of cartilage, infiltration by many polymorphonuclear neutrophils, and the marked ingrowth of fibrous tissue in the COT group. Sagittal and coronal diameters and cross-sectional areas were significantly affected more severely after a COT than after an ODT. CONCLUSION: Our new modification of percutaneous dilatational tracheostomy, named "open dilatational tracheostomy," was successfully applied to a small, growing animal model and showed more favorable and consistent healing of trachea compared with COT. Therefore, the authors' new tracheostomy procedure could be applied to children who require short-term tracheostomy at any age in clinical settings.

Animals↗

PubMed2002

Pharyngoesophageal reconstruction with lateral thigh free flap.

BACKGROUND: We evaluated the use of a lateral thigh free flap in pharyngoesophageal reconstruction, which is often overlooked and less widely used despite its distinct advantages. METHODS: This study reviewed the patient's medical records, including the patient's age, gender, histopathologic diagnosis, surgical defects, flap size, flap survival, donor and recipient site complications, and swallowing function and voice rehabilitation. RESULTS: Twelve lateral thigh free flaps were used to primarily reconstruct the pharyngoesophagus in 11 patients after tumor resection from July 1997 to May 1999. Eleven of the 12 flaps (91.7%) were transferred successfully. In one patient, the flap failure occurred as a result of venous thrombosis, and therefore another lateral thigh free flap from the opposite thigh was used 3 days later. The swallowing function was restored in all patients. Prosthetic voice rehabilitation was successfully achieved in all five patients, who primarily underwent tracheoesophageal punctures. No frank fistula or stricture developed. Significant donor site morbidity was not noted. CONCLUSIONS: The lateral thigh free flap is useful and reliable in selected cases of pharyngoesophageal reconstruction and versatile in flap design with favorable functional outcomes of swallowing and voice rehabilitation with minimal donor site morbidity.

Aged↗

PubMed2002

Tissue-engineered cartilage on biodegradable macroporous scaffolds: cell shape and phenotypic expression.

OBJECTIVE: The purpose of the study was to establish in vitro culture of chondrocytes on biodegradable, poly(D,L-lactic-co-glycolic acid) [PLGA] scaffolds. STUDY DESIGN: Laboratory experiment using cartilage of rat rib and biodegradable scaffolds. METHODS: Chondrocytes were cultured on a poly-hydroxyethyl methacrylate (poly-HEMA)-coated dish, proliferated, and transferred into the PLGA scaffolds. Phenotypic expression of cells was examined according to the condition of poly-HEMA coating. Morphological, biochemical, and immunohistochemical characteristics of cells cultured within PLGA scaffolds were also examined. RESULTS: Chondrocytes cultured on a poly-HEMA-coated dish aggregated into distinct nodules containing large clusters of spherical cells and showed cartilage-specific phenotype, collagen type II. The results of immunostaining andreverse transcriptase-polymerase chain reaction of cells cultured within PLGA scaffolds showed cartilage-specific morphological appearance and structural characteristics such as lacunae and expression of collagen type II. CONCLUSION: The chondrocytes cultured on a poly-HEMA-coated dish and PLGA scaffolds showed chondrocyte-specific phenotypes and morphological appearance.

Animals↗

PubMedDate not supplied

The pattern of lymphatic metastasis of malignant tumors in the periorbital area.

BACKGROUND AND OBJECTIVES: The rarity of malignant tumors in the periorbital area makes it difficult to assess the patterns of lymphatic spread and to determine the optimal extent of treatment. The objective of this study was to analyze the patterns of lymphatic metastasis in malignant tumors arising from the periorbital area according to the primary site and to assess the optimal extent of surgical treatment for these tumors. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 8 patients with malignant tumors in the periorbital area from January 1997 to June 2002. The mean duration of follow-up was 27.5 months. Five primary tumors were located in the medial half of the periorbital area, 2 tumors in both medial and lateral halves, and 1 tumor in the lateral half. The pathological diagnoses were 3 squamous cell carcinomas, 2 adenoid cystic carcinomas, 2 sebaceous carcinomas, and 1 basal cell carcinoma. RESULTS: The lymphatic metastasis was observed in 4 of 8 patients who had a relatively large (> or =4 cm) primary tumor or poorly differentiated tumor. Four of 7 tumors involving the medial half of the periorbital area exhibited lymphatic spread to the periparotid lymph node and level II cervical lymph node groups. CONCLUSION: The results of this study suggest that more aggressive management of the parotid area is necessary in malignant tumors arising from the periorbital area, even in the medial half of the periorbital area.

Adult↗

PubMedDate not supplied

Endoscope-assisted submandibular sialadenectomy: a new minimally invasive approach to the submandibular gland.

PURPOSE: Although submandibular sialadenectomy with a minimal incision improves overall cosmetic outcomes, visualization of the surgical field exposure is relatively limited as compared with that in the conventional procedure. To overcome this limitation, we applied the endoscope system to submandibular sialadenectomy. The aim of this study was to evaluate the technical feasibility and potential role of our endoscope-assisted submandibular sialadenectomy (EASS). MATERIALS AND METHODS: We performed EASS on 5 patients, 3 of whom had intraparenchymal sialolithiasis and 2 of whom had pleomorphic adenomas. The dissection was carried out by bipolar dissection with a 4-mm nasal endoscope system. RESULTS: The procedure achieved successful results for all 5 patients except for 1 who had severe adhesion to the adjacent tissues; this patient suffered from postoperative lingual nerve paresthesia. All the patients achieved good cosmetic outcomes. CONCLUSIONS: An EASS with bipolar dissection is technically feasible and secures a better surgical view through a minimal incision. However, for patients with severe adhesion to the adjacent tissues, conversion to the wide-open procedure would be safer.

Adenoma, Pleomorphic↗

PubMedDate not supplied

Basal cell adenoma of the parotid gland: characteristics of 2-phase helical computed tomography and magnetic resonance imaging.

OBJECTIVE: The goal of this study was to report the radiologic characteristics of basal cell adenoma of the parotid gland, which is a relatively rare neoplasm. METHODS: A radiology and otolaryngology specialist reviewed the 2-phase helical computed tomography (CT) (n = 6) and/or magnetic resonance (MR) imaging (n = 2) scans of 7 patients with basal cell adenoma. The authors evaluated the imaging characteristics, including tumor size, location, contour and margin, internal density or signal intensity, contrast enhancement pattern, and presence of calcification. The imaging features were then analyzed and correlated with the pathologic findings. RESULTS: All the tumors presented as small (less than 3 cm), well-encapsulated, round or oval masses on CT or MR imaging. On the 2-phase CT scan, the mostly solid-looking tumors (n = 4) showed marked contrast enhancement on the early phase, and there was a subsequent decrease in attenuation on the delayed phase. These tumors were classified as the solid subtype on histologic examination. Meanwhile, the tumors with large cystic areas (n = 2) showed gradual and additional enhancement on the delayed phase and were classified as the tubular or trabecular subtype on pathologic evaluation. There were small spots of low attenuation in the tumors of the solid subtype, which were proved to be intratumoral microcysts in the pathologic correlation. Calcification was found in a tumor. CONCLUSIONS: Basal cell adenomas of the parotid gland present as small well-marginated tumors and appear as masses with central large cysts or solid masses with microcysts on CT and MR imaging scans. Basal cell adenomas of the parotid gland had at least 2 different enhancement patterns on the 2-phase helical CT scans, and the enhancement patterns and imaging architecture were related to the histologic subtype of the tumors.

Adenoma↗