PURPOSE: To determine the incidence of and the systemic risk factors for postoperative vitreous hemor-rhage(PVH). METHOD: The records of 503 consecutive diabetic vitrectomy cases were reviewed. RESULT: Eighty-seven eyes(17.3%) had at least one episode of PVH. Sixty-five eyes(12.9%) had PVH within 3 months after vitrectomy, and the mean onset time of the first episode of PVH was about 13 weeks after vitrectomy. The mean follow-up period was 17.2 months in non-hemorrhage group, and 21.9 months in hemorrhage group. While 34 eyes(29.6%) had spontaneous absorption of blood, 42 eyes(36.5%) required air(or gas)-fluid exchange and 39 eyes(33.9%) vitreous cavity lavage. Using univariate analysis, the factors associated with increased incidence of PVH include type 1 diabetes mellitus(p=0.01), method of glycemia control(p=0.02), anemia(p=0.04), and hypercholesterolemia(p=0.005). Multivariate analysis revealed diabetic nephropathy(p=0.02) and hypercholesterolemia(p=0.01) were the risk factors. Five eyes(1.0%) lost light perception, 7 eyes(1.4%) had rhegmatogenous retinal detachment, and 11 eyes(2.2%) had neovascular glaucoma. CONCLUSION: Vitreous hemorrhage after diabetic vitrectomy occurred in the 17.3%, three quarters of them within 3 months. About one third had spontaneous clearing, and two-thirds required reoperation. Diabetic nephropathy and hypercholesterolemia were the systemic risk factors of vitreous hemorrhage after diabetic vitrectomy.
Absorption ; Diabetic Nephropathies ; Follow-Up Studies ; Glaucoma, Neovascular ; Hemorrhage ; Hypercholesterolemia ; Incidence ; Multivariate Analysis ; Reoperation ; Retinal Detachment ; Risk Factors* ; Therapeutic Irrigation ; Vitrectomy* ; Vitreous Hemorrhage*

PURPOSE: B1 field of birdcage RF (radiofrequency) coil that is used most for brain imaging in magnetic resonance imaging (MRI) decreases toward endring from the coil center. We investigated how much RF B1 homogeneity effect the endcap shield brings form the coil center as it towards to endcap region. MATERIALS AND METHODS: We compared RF B1 field distribution by each finite difference time domain (FDTD) simulations for lowpass, highpass and hybrid birdcage RF coils. We selected the highpass birdcage RF coil that was the highest RF B1 field condition as simulation result, and studied how much RF B1 homogeneity effect was occurred when endcap shield was applied to endring area. RESULTS: B1 field of the highpass birdcage RF coil was higher than other birdcage RF coil types as simulation result. However, the RF B1 homogeneity was lower than other coil types. RF B1 field of highpass birdcage RF coil with endcap shield is similar with RF B1 field of hybrid birdcage RF coil and the overall RF B1 homogeneity in sagittal direction was better. CONCLUSION: In this paper, proposed method can apply improving RF B1 homogeneity of RF coil in clinical examination.
Magnetic Resonance Imaging* ; Neuroimaging

PURPOSE: To investigate the patterns of care for patients with nasopharyngeal carcinoma (NPC) in South Korea. MATERIALS AND METHODS: A multi-institutional retrospective study was performed (Korean Radiation Oncology Group [KROG] 11-06) on a total of 1,445 patients from 15 institutions. RESULTS: Of the 1,445 patients, more than half were stages III (39.9%) and IV (35.8%). In addition to patterns of care, we also investigated trends over time with the periods 1988-1993, 1994-2002, and 2003-2011. The frequencies of magnetic resonance imaging and positron emission tomography-computed tomography were markedly increased in the third period compared to previous 2 periods. Concurrent chemoradiation (CCRT) was performed on 894 patients (61.9%), neoadjuvant chemotherapy on 468 patients (32.4%), and adjuvant chemotherapy on 366 patients (25.3%). Of stage II-IV patients, CCRT performed on 78.8% in 2003-2011 compared to 15.0% in 1988-1993. For patients treated with CCRT, cisplatin was the most commonly used agent in 81.3% of patients. Over the periods of time, commonly used radiotherapy (RT) techniques were changed from 2-dimensional RT (1988-1993, 92.5%) to 3-dimensional RT (2003-2011, 35.5%) or intensity-modulated RT (IMRT; 2003-2011, 56.5%). Median RT doses given to primary tumors, high-risk lymphatics, and low-risk lymphatics were 70.0 Gy, 58.1 Gy, and 48.0 Gy, respectively. Adoption of IMRT increased the dose per fraction and escalated total radiation dose. CONCLUSION: Assessment of the patterns of care for NPC patients in South Korea demonstrated that management for NPC including diagnostic imaging, treatment regimen, RT techniques and dose schedule, advanced in accordance with the international guidelines.
Appointments and Schedules ; Chemotherapy, Adjuvant ; Cisplatin ; Diagnostic Imaging ; Drug Therapy ; Electrons ; Humans ; Korea* ; Magnetic Resonance Imaging ; Nasopharyngeal Neoplasms ; Radiation Oncology ; Radiotherapy ; Retrospective Studies

PURPOSE: We compared the treatment results and toxicity in nasopharyngeal carcinoma (NPC) patients treated with concurrent chemotherapy (CCRT) alone (the CRT arm) or neoadjuvant chemotherapy followed by CCRT (the NCT arm). MATERIALS AND METHODS: A multi-institutional retrospective study was conducted to review NPC patterns of care and treatment outcome. Data of 568 NPC patients treated by CCRT alone or by neoadjuvant chemotherapy followed by CCRT were collected from 15 institutions. Patients in both treatment arms were matched using the propensity score matching method, and the clinical outcomes were analyzed. RESULTS: After matching, 300 patients (150 patients in each group) were selected for analysis. Higher 5-year locoregional failure-free survival was observed in the CRT arm (85% vs. 72%, p=0.014). No significant differences in distant failure-free survival (DFFS), disease-free survival (DFS), and overall survival were observed between groups. In subgroup analysis, the NCT arm showed superior DFFS and DFS in stage IV patients younger than 60 years. No significant difference in compliance and toxicity was observed between groups, except the radiation therapy duration was slightly shorter in the CRT arm (50.0 days vs. 53.9 days, p=0.018). CONCLUSION: This study did not show the superiority of NCT followed by CCRT over CCRT alone. Because NCT could increase the risk of locoregional recurrences, it can only be considered in selected young patients with advanced stage IV disease. The role of NCT remains to be defined and should not be viewed as the standard of care.
Arm ; Chemoradiotherapy ; Compliance ; Disease-Free Survival ; Drug Therapy* ; Humans ; Induction Chemotherapy ; Methods ; Nasopharyngeal Neoplasms ; Propensity Score* ; Radiotherapy ; Recurrence ; Republic of Korea ; Retrospective Studies* ; Standard of Care ; Treatment Outcome

PURPOSE: The purpose of this study was to investigate the effect of hospital case volume on clinical outcomes in patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Data on 1,073 patients with cT1-4N0-3M0 NPC were collected from a multi-institutional retrospective database (KROG 11-06). All patients received definitive radiotherapy (RT) either with three-dimensional-conformal RT (3D-CRT) (n=576) or intensity-modulated RT (IMRT) (n=497). The patients were divided into two groups treated at high volume institution (HVI) (n=750) and low volume institution (LVI) (n=323), defined as patient volume ≥ 10 (median, 13; range, 10 to 18) and < 10 patients per year (median, 3; range, 2 to 6), respectively. Endpoints were overall survival (OS) and loco-regional progression-free survival (LRPFS). RESULTS: At a median follow-up of 56.7 months, the outcomes were significantly better in those treated at HVI than at LVI. For the 614 patients of propensity score-matched cohort, 5-year OS and LRPFS were consistently higher in the HVI group than in the LVI group (OS: 78.4% vs. 62.7%, p < 0.001; LRPFS: 86.2% vs. 65.8%, p < 0.001, respectively). According to RT modality, significant difference in 5-year OS was observed in patients receiving 3D-CRT (78.7% for HVI vs. 58.9% for LVI, p < 0.001) and not in those receiving IMRT (77.3% for HVI vs. 75.5% for LVI, p=0.170). CONCLUSION: A significant relationship was observed between HVI and LVI for the clinical outcomes of patients with NPC. However, the difference in outcome becomes insignificant in the IMRT era, probably due to the standardization of practice by education.
Cohort Studies ; Disease-Free Survival ; Education ; Follow-Up Studies ; Humans ; Nasopharyngeal Neoplasms ; Radiotherapy ; Radiotherapy, Intensity-Modulated ; Retrospective Studies* ; Treatment Outcome

OBJECTIVE: Schizophrenia, a devastating mental disorder, displays a wide range of cognitive impairments including attentional impairment. Prepulse inhibition (PPI), in which a startle response to a loud acoustic noise is reduced by a preceding auditory stimulus of a lower intensity, is impaired in schizophrenic patients and rats injected with apomorphine (APO) or phencyclidine (PCP) mimicking attentional deficits in schizophrenics. Here we examined therapeutic efficacy of a newly developed atypical antipsychotic compound (YKP1447;YKP) on PPI impairment induced by various doses of APO and PCP. METHODS: This study was composed of 3 experiments. YKP (0.5-15 mg/kg) or vehicle (VEH) was administered 15 min before the injection of APO (0.5 mg/kg, Exp1) or PCP (2.0 mg/kg, Exp2:1.5 mg/kg, Exp3). They were then tested for PPI in which a mix of startle stimulus and prepulse was presented. RESULTS: APO or PCP treatment effectively impaired PPI in tested animals (VEH/APO or VEH/PCP). Impaired PPI in APO group was reversed in animals that were pretreated with YKP (5-10 mg/kg) (Exp1). However YKP treatment was not effective in PCP group (Exp2-3). CONCLUSION: High concentration of YKP pretreatment had antipsychotic effect on APO-induced impairment in attentional function suggesting that the compound could potentially be used to treat cognitive impairment due to increased dopaminergic receptorbinding.
Acoustics ; Animals ; Antipsychotic Agents ; Apomorphine ; Humans ; Mental Disorders ; Noise ; Phencyclidine ; Rats ; Schizophrenia

BACKGROUND/AIMS: This study examined the correlation between pneumothorax detected by immediate post-transthoracic needle aspiration-biopsy (TTNB) chest computed tomography (CT) and overt pneumothorax detected by chest PA, and investigated factors that might influence the correlation. METHODS: Adult patients who had undergone CT-guided TTNB for lung lesions from May 2003 to June 2007 at Seoul National University Bundang Hospital were included. Immediate post-TTNB CT and chest PA follow-up at 4 and 16 hours after CT-guided TTNB were performed in 934 patients. RESULTS: Pneumothorax detected by immediate chest CT (CT-pneumothorax) was found in 237 (25%) and overt pneumothorax was detected by chest PA follow-up in 92 (38.8%) of the 237 patients. However, overt pneumothorax was found in 18 (2.6%) of the 697 patients without CT-pneumothorax. The width and depth of CT-pneumothorax were predictive risk factors for overt pneumothorax. CONCLUSIONS: CT-pneumothorax is very sensitive for predicting overt pneumothorax, and the width and depth on CT-pneumothorax are reliable risk factors for predicting overt pneumothorax.
Adult ; Aged ; Aged, 80 and over ; Biopsy, Needle/*adverse effects ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Pneumothorax/epidemiology/*radiography ; Radiography, Thoracic/*methods ; Retrospective Studies ; Thorax/*pathology ; Tomography, X-Ray Computed/*methods

If ventricular fibrillation develops after acute myocardial infarction, it should be treated immediately with the external electrical cardioversion and antiarrhythmic agents, followed by the rapid correction of the reversible and underlying cause. Nevertheless, if ventricular fibrillation recurs, ICD(implantable cardioverter-defibrillator) therapy is necessary. ICD is an important nonpharmacological option in the treatment of malignant ventricular arrhythmias. A 53 year old man was admitted into our hospital with a severe chest pain of 9 days. On cardiac catheterization, a significant stenosis at the mid-left anterior descending coronary artery and a huge ventricular aneurysm were found. Then PTCA(percutaneous transluminal coronary angioplasty) with a stent was taken. Three days later, two episodes of ventricular fibrillation developed and it was treated with electrical cardioversion and antiarrhythmic agents. On the second look of cardiac catheterization, a subacute closure of the stented site was detected and then the culprit leision was recanalized with repeated PTCA and another stent was implanted. But ventricular fibrillation recurred although the stented lesion still patent on the third look of cardiac catheterization. After all, we implanted ICD on him. 46 Episodes of ventricular fibrillations developed at the same day and the next day of ICD implantation. All of the episodes of ventricular fibrillation were successfully converted to sinus rhythm with shocks from ICD. Since then, the frequency of ventricular fibrillation decreased with IABP(intraaortic balloon pump) therapy. We report the first case of malignant ventricular fibrillation after myocardial infarction which was uncontrolled with conventional therapy, but effectively treated with ICD.
Aneurysm ; Arrhythmias, Cardiac ; Cardiac Catheterization ; Cardiac Catheters ; Chest Pain ; Constriction, Pathologic ; Coronary Vessels ; Electric Countershock ; Humans ; Middle Aged ; Myocardial Infarction* ; Shock ; Stents ; Ventricular Fibrillation*

PURPOSE: In order to develop the national guide-lines for the standardization of radiotherapy we are planning to establish a web-based, on-line data-base system for laryngeal cancer. As a first step this study was performed to accumulate the basic clinical information of laryngeal cancer and to determine the items needed for the data-base system. MATERIALS AND METHODS: We analyzed the clinical data of patients who were treated under the diagnosis of laryngeal cancer from January 1998 through December 1999 in the South-west area of Korea. Eligibility criteria of the patients are as follows: 18 years or older, currently diagnosed with primary epithelial carcinoma of larynx, and no history of previous treatments for another cancers and the other laryngeal diseases. The items were developed and filled out by radiation oncologist who are members of Korean Southwest Radiation Oncology Group. SPSS v10.0 software was used for statistical analysis. RESULTS: Data of forty-five patients were collected. Age distribution of patients ranged from 28 to 88 years (median, 61). Laryngeal cancer occurred predominantly in males (10:1 sex ratio). Twenty-eight patients (62%) had primary cancers in the glottis and 17 (38%) in the supraglottis. Most of them were diagnosed pathologically as squamous cell carcinoma (44/45, 98%). Twenty-four of 28 glottic cancer patients (86%) had AJCC (American Joint Committee on Cancer) stage I/II, but 50% (8/16) had in supraglottic cancer patients (p=0.02). Most patients (89%) had the symptom of hoarseness. Indirect laryngoscopy was done in all patients and direct laryngoscopy was performed in 43 (98%) patients. Twenty-one of 28 (75%) glottic cancer cases and 6 of 17 (35%) supraglottic cancer cases were treated with radiation alone, respectively. The combined treatment of surgery and radiation was used in 5 (18%) glottic and 8 (47%) supraglottic patients. Chemotherapy and radiation was used in 2 (7%) glottic and 3 (18%) supraglottic patients. There was no statistically significant difference in the use of combined modality treatments between glottic and supraglottic cancers (p=0.20). In all patients, 6 MV X-ray was used with conventional fractionation. The fraction size was 2 Gy in 80% of glottic cancer patients compared with 1.8 Gy in 59% of the patients with supraglottic cancers. The mean total dose delivered to primary lesions were 65.98 Gy and 70.15 Gy in glottic and supraglottic patients treated, respectively, with radiation alone. Based on the collected data, 12 modules with 90 items were developed for the study of the patterns of care in laryngeal cancer. CONCLUSION: The study items for laryngeal cancer were developed. In the near future, a web system will be established based on the items investigated, and then a nation-wide analysis on laryngeal cancer will be processed for the standardization and optimization of radiotherapy.
Age Distribution ; Carcinoma, Squamous Cell ; Diagnosis ; Drug Therapy ; Glottis ; Hoarseness ; Humans ; Joints ; Korea ; Laryngeal Diseases ; Laryngeal Neoplasms* ; Laryngoscopy ; Larynx ; Male ; Radiation Oncology ; Radiotherapy*

PURPOSE: To investigate the care patterns for radiation therapy and to determine inter-hospital differences for patients with laryngeal carcinoma in Korea. MATERIALS AND METHODS: A total of 237 cases of laryngeal carcinoma (glottis, 144; supraglottis, 93) assembled from 23 hospitals, who underwent irradiation in the year of 1998 and 1999, were retrospectively analyzed to investigate inter-hospital differences with respect to radiotherapy treatment. We grouped the 23 hospitals based on the number of new patients annually irradiated in 1998; and designated them as group A (> or =900 patients), group B (> or =400 patients and <900 patients), and group C (<400 patients). RESULTS: The median age of the 237 patients was 62 years (range, 25 to 88 years), of which 216 were male and 21 were female. The clinical stages were distributed as follows: for glottis cancer, I; 61.8%, II; 21.5%, III; 4.2%, IVa; 11.1%, IVb; 1.4%, and in supraglottic cancer, I; 4.3%, II; 19.4%, III; 28.0%, IVa; 43.0%, IVb; 5.4%, respectively. Some differences were observed among the 3 groups with respect to the dose calculation method, radiation energy, field arrangement, and use of an immobilization device. No significant difference among 3 hospital groups was observed with respect to treatment modality, irradiation volume, and median total dose delivered to the primary site. CONCLUSION: This study revealed that radiotherapy process and patterns of care are relatively uniform in laryngeal cancer patients in Korean hospitals, and we hope this nationwide data can be used as a basis for the standardization of radiotherapy for the treatment of laryngeal cancer.
Female ; Glottis ; Humans ; Immobilization ; Korea ; Laryngeal Neoplasms ; Male ; Retrospective Studies