PURPOSE: To investigate the feasibility and accuracy of Proton Resonance Frequency (PRF) shift based magnetic resonance (MR) temperature mapping utilizing the selfdeveloped center array-sequencing phase unwrapping (PU) method for non-invasive temperature monitoring. MATERIALS AND METHODS: The computer simulation was done on the PU algorithm for performance evaluation before further application to MR thermometry. The MR experiments were conducted in two approaches namely PU experiment, and temperature mapping experiment based on the PU technique with all the image postprocessing implemented in MATLAB. A 1.5T MR scanner employing a knee coil with T2* GRE (Gradient Recalled Echo) pulse sequence were used throughout the experiments. Various subjects such as water phantom, orange, and agarose gel phantom were used for the assessment of the self-developed PU algorithm. The MR temperature mapping experiment was initially attempted on the agarose gel phantom only with the application of a custom-made thermoregulating water pump as the heating source. Heat was generated to the phantom via hot water circulation whilst temperature variation was observed with T-type thermocouple. The PU program was implemented on the reconstructed wrapped phase images prior to map the temperature distribution of subjects. As the temperature change is directly proportional to the phase difference map, the absolute temperature could be estimated from the summation of the computed temperature difference with the measured ambient temperature of subjects. RESULTS: The PU technique successfully recovered and removed the phase wrapping artifacts on MR phase images with various subjects by producing a smooth and continuous phase map thus producing a more reliable temperature map. CONCLUSION: This work presented a rapid, and robust self-developed center arraysequencing PU algorithm feasible for the application of MR temperature mapping according to the PRF phase shift property.
Artifacts ; Citrus sinensis ; Computer Simulation ; Heating ; Hot Temperature ; Knee ; Magnetic Resonance Spectroscopy ; Protons ; Sepharose ; Thermography ; Thermometry ; Water

PURPOSE: This study proposes the keyhole method in order to improve the time resolution of the proton resonance frequency(PRF) MR temperature monitoring technique. The values of Root Mean Square (RMS) error of measured temperature value and Signal-to-Noise Ratio(SNR) obtained from the keyhole and full phase encoded temperature images were compared. MATERIALS AND METHODS: The PRF method combined with GRE sequence was used to get MR temperature images using a clinical 1.5T MR scanner. It was conducted on the tissue-mimic 2% agarose gel phantom and swine's hock tissue. A MR compatible coaxial slot antenna driven by microwave power generator at 2.45GHz was used to heat the object in the magnetic bore for 5 minutes followed by a sequential acquisition of MR raw data during 10 minutes of cooling period. The acquired raw data were transferred to PC after then the keyhole images were reconstructed by taking the central part of K-space data with 128, 64, 32 and 16 phase encoding lines while the remaining peripheral parts were taken from the 1st reference raw data. The RMS errors were compared with the 256 full encoded self-reference temperature image while the SNR values were compared with the zero filling images. RESULTS: As phase encoding number at the center part on the keyhole temperature images decreased to 128, 64, 32 and 16, the RMS errors of the measured temperature increased to 0.538, 0.712, 0.768 and 0.845degrees C, meanwhile SNR values were maintained as the phase encoding number of keyhole part is reduced. CONCLUSION: This study shows that the keyhole technique is successfully applied to temperature monitoring procedure to increases the temporal resolution by standardizing the matrix size, thus maintained the SNR values. In future, it is expected to implement the MR real time thermal imaging using keyhole method which is able to reduce the scan time with minimal thermal variations.
Hot Temperature ; Magnetics ; Magnets ; Microwaves ; Protons ; Sepharose ; Tarsus, Animal ; Thermography

Cesarean hysterectomy is associated with high risks of severe blood loss, postoperative complication, and maternal morbidity. This study was undertaken to identify the risk factors of cesarean hysterectomy and to reduce the postoperative complications and maternal morbidity. There were 6,362 deliveries between January 1992 and December 1996 at department of obstetrics and gynecology, Inchon Christian Hospital. 1'he results of this study were as follows, 15 cases of cesarean hysterectomy were performed during this period. Cesarean hysterectomy was performed in 10 cases (0.32 %) among 3178 cesarean deliveries and in 5 cases (0.16 %) among 3184 vaginal deliveries. The incidence of cesarean hysterectomy was 0.24 % (15/6,362). The age of patients ranged from 24 to 38 years old. The maternal mortality and morbidity were 0 % (0/15) and 86.7% (13/15), respectively. Indications for cesarean hysterectomy were uterine atony (53.3 %), uterine myoma with pregnancy (20.0 %), placenta accreta and/or increta(20.0 %), and placenta previa (6.7 %) in orders. The associated risk factors of cesarean hysterectomy were prior cesarean delivery (46.7 %) and placenta previa (6.7 %). The postoperative complications were anemia (60.0%), febrile morbidity (13.3 %), paralytic ileus (6.7 %), and wound disruption (6.7 %). We concluded that risk factors of cesarean hysterectomy were cesarean delivery, prior cesarean delivery, uterine myoma with pregnancy, placenta accreta and/or increta, and placenta previa and that sufficient fresh blood and careful prenatal care were needed in risk group of postpartum bleeding.
Adult ; Anemia ; Gynecology ; Hemorrhage ; Humans ; Hysterectomy* ; Incheon ; Incidence ; Intestinal Pseudo-Obstruction ; Leiomyoma ; Maternal Mortality ; Obstetrics ; Placenta Accreta ; Placenta Previa ; Postoperative Complications ; Postoperative Hemorrhage ; Postpartum Period ; Pregnancy ; Prenatal Care ; Risk Factors ; Uterine Inertia ; Wounds and Injuries

BACKGROUND: Although a skin test is the primary option for detecting allergen-specific IgE in clinics, the serum IgE immunoassay is also important because it allows for the diagnosis of allergy without any accompanying adverse effect on the patient. However, the low detection limit of IgE levels by immunoassay may restrict the use of the method in some occasions, and improving its sensitivity would thus have a significant implication in allergy-immunology clinics. METHODS: In this study, we attempted to detect specific serum IgE by using immuno-polymerase chain reaction (IPCR) which combines the antigen-antibody specificity of enzyme-linked immunosorbent assays (ELISAs) with the amplification power of PCR. RESULTS: Our results demonstrated that Blo t5-specific serum IgE can be detected by IPCR with a 100-fold higher sensitivity than ELISA, and cross-reactivity of serum IgE to other mite allergens is able to be analyzed by using only 0.3 microliter of serum sample. Use of real-time IPCR seemed to permit more convenient determination of specific serum IgE as well. CONCLUSION: We believe that IPCR can serve as a valuable tool in determining specific serum IgE, especially when the amount of serum sample is limited.
Allergens ; Antigens, Dermatophagoides ; Arthropod Proteins ; Cysteine Endopeptidases ; Enzyme-Linked Immunosorbent Assay ; Humans ; Hypersensitivity ; Immunoassay ; Immunoglobulin E ; Limit of Detection ; Mites ; Polymerase Chain Reaction ; Real-Time Polymerase Chain Reaction ; Sensitivity and Specificity ; Skin Tests

Tendon and ligament (T/L) have been known to be obviously different from each other in tissue level. However, due to the overlapping gene markers, distinction in cellular level has not been clearly verified yet. Recently, the use of nuclear magnetic resonance (NMR) spectroscopy has shown the potential to detect biological markers in cellular level. Therefore, in this study we applied a non-invasive technique based on NMR spectroscopy to establish biomarkers to distinguish between T/L fibroblasts. In addition the cellular morphologies and gene expression patterns were also investigated for comparison through optical microscopy and real-time polymerase chain reaction (PCR). No difference was observed from morphology and real-time PCR results, either as expected. However, we found clear differences in their metabolomic spectra using ¹H NMR spectroscopy. The calculated integral values of fatty acids (with chemical shifts at ~0.9, 1.26, 1.59, 2.05, 2.25, and 2.81 ppm), lactate (~1.33 ppm), and leucine (~2.72 ppm) were significantly different between the two types of fibroblasts. To be specific tendon group exhibited higher level of the metabolite than ligament group. In conclusion, in-cell metabolomic evaluation by NMR technique used in this study is believed to provide a promising tool in distinguishing cell types, especially T/L cells, which cannot be classified by conventional biological assays.
Biological Assay ; Biomarkers ; Fatty Acids ; Fibroblasts* ; Gene Expression ; Genes, Overlapping ; Lactic Acid ; Leucine ; Ligaments* ; Magnetic Resonance Spectroscopy* ; Metabolomics ; Microscopy ; Real-Time Polymerase Chain Reaction ; Spectrum Analysis* ; Tendons*

PURPOSE: Gastrointestinal stromal tumors (GISTs) possess highly variable clinical behaviors and the study thereof is insufficient. There are no standard guidelines for diagnosis and treatment of GISTs, so it is difficult to predict recurrences and conduct appropriate treatments. Throughout the last 10 years of experiences with GIST patients, we have identified the variables predicting recurrences and classified the risk groups by NIH classification, Fletcher risk stratification and UICC TNM stage. METHODS: From January 1998 to December 2007, 88 patients with pathologic confirm and surgical resection were diagnosed with GISTs. GISTs were diagnosed when the tumor had characteristic histologic features and confirmed positive by KIT, CD34, or PDGFRA. RESULTS: The size, mitotic index, existence of symptoms, and origins of tumor correlate statistically with recurrence (0.002, <0.001, 0.027, 0.011). The NIH classification, Fletcher risk stratification and UICC TNM stage are correlated with recurrence (0.001, <0.001, <0.001) and 5 year disease free survival, statistically (0.009, <0.001, <0.001). Fifteen patients experienced recurrences. 14 patients were treated with imatinib, and 6 of them showed a response to the treatment. All 4 patients who had R1 resection did not survived due to the progression of the disease. CONCLUSION: The patients with large, high mitotic index, symptomatic, or extra-gastric tumor require strict surveillance. Also, patients with low risk must be under surveillance due to the possibility of recurrence. It is important to perform R0, en bloc resection. Although the imatinib is the treatment of choice with recurred or metastatic GISTs, the disease is likely to develop resistance, further studies on newly targeted therapy is in need.
Benzamides ; Disease-Free Survival ; Gastrointestinal Stromal Tumors ; Humans ; Imatinib Mesylate ; Mitotic Index ; Piperazines ; Pyrimidines ; Recurrence ; Survival Rate

BACKGROUND: Hepatocellular carcinoma (HCC) recurrence and development of de novo malignancy (DNM) after liver transplantation (LT) are the major causes of late recipient death.METHODS: We analyzed the incidence of extrahepatic DNM following living donor LT according to the status of pretransplant hepatic malignancy. We selected 2,076 adult patients who underwent primary LDLT during 7 years from January 2010 to December 2016.RESULTS: The pretransplant hepatic malignancy group (n = 1,012) showed 45 cases (4.4%) of the following extrahepatic DNMs: posttransplant lymphoproliferative disease (PTLD) in 10; lung cancer in 10; stomach cancer in 6; colorectal cancer in 5; urinary bladder cancer in 3; and other cancers in 11. The pretransplant no hepatic malignancy group (n = 1,064) showed 25 cases (2.3%) of the following extrahepatic DNMs: colorectal cancer in 3; stomach cancer in 3; leukemia in 3; lung cancer in 3; PTLD in 2; prostate cancer in 2; and other cancers in 9. Incidences of extrahepatic DNM in the pretransplant hepatic malignancy and no hepatic malignancy groups were as follows: 1.1% and 0.5% at 1 year, 3.2% and 2.0% at 3 years, 4.6% and 2.5% at 5 years, and 5.4% and 2.8% at 8 years, respectively (P = 0.006). Their overall patient survival rates were as follows: 97.3% and 97.2% at 1 year, 91.6% and 95.9% at 3 years, 89.8% and 95.4% at 5 years, and 89.2% and 95.4% at 8 years, respectively (P < 0.001). Pretransplant hepatic malignancy was the only significant risk factor for posttransplant extrahepatic DNM.CONCLUSION: Our results suggest that patients who had pretransplant hepatic malignancy be followed up more strictly because they have a potential risk of primary hepatic malignancy recurrence as well as a higher risk of extrahepatic DNM than patients without pretransplant hepatic malignancy.

PURPOSE: Hepatorenal syndrome (HRS) is a fatal complication in patients with end-stage liver disease awaiting liver transplantation (LT). HRS often develops in patients with high model for end-stage liver disease (MELD) score. This study investigated the outcomes of peritransplant management of HRS in a high-volume LT center in Korea for 2 years. METHODS: A total of 157 recipients that deceased donor liver transplantation (DDLT) from January 2017 to December 2018 were included. In-hospital mortality (IHM) was analyzed in relation to pre- and posttransplant application of renal replacement therapy (RRT). RESULTS: Primary diagnoses for DDLT were alcoholic liver disease (n = 61), HBV-associated liver cirrhosis (n = 48), retransplantation for chronic graft failure (n = 24), and others (n = 24). Mean MELD score was 34.6 ± 6.2 with 72 patients at Korean Network for Organ Sharing MELD status 2 (45.9%), 43 at status 3 (27.4%), 36 at status 4 (22.9%), and 6 at status 5 (3.8%). Pretransplant RRT was performed in 16 patients (10.2%) that did not show IHM. Posttransplant RRT was performed in 69 patients (44.0%), for whom IHM incidence was 15.9%. In 53 patients that had undergone de novo posttransplant RRT, IHM incidence increased to 20.8%. IHM in the 88 patients not requiring RRT was 2.3%. CONCLUSION The majority of adult DDLT recipients in Korean MELD score-based allocation system have very high MELD scores, which is often associated with HRS. Pretransplant RRT appears to improve posttransplant survival outcomes. We thereby recommend that, if indicated, pretransplant RRT be performed while awaiting DDLT.

Objective: This study aimed to investigate the perception of emergency medical service (EMS) providers and medical directors toward the field skill proficiency of EMS providers. We further examined differences in perception according to the certification and hospital career of individuals. Methods: This survey was conducted enrolling all active EMS providers in Busan, Ulsan, and Gyeongnam, as well as emergency physicians who participated in direct medical direction. Pre-developed questionnaires were sent as text messages to individual EMS providers and emergency physicians using an internet-based survey tool (Google Forms).Questionnaires were composed of 25 items in 7 categories: “airway management”, “ventilatory support”, “circulatory support”, “field assessment and management of trauma patients”, “field assessment and management of patients with chest pain”, “field assessment and management of patients with neurologic symptoms”, and “other items”. The response was based on a five-point Likert scale, where 0 score indicated no experience at all. Results: The questionnaire was distributed to 1,781 EMS providers and 52 medical directors; of these, 1,314 (73.7%) EMS providers and 34 (65.3%) medical directors completed the survey. EMS providers rated themselves as above average (3 points) for most of the questions. However, the majority responded that they had no experience or low proficiency in endotracheal intubation and prehospital delivery (median 2; interquartile range [IQR], 0-3). Conversely, medical directors assessed the EMS provider’s proficiency as above average in use of I-gel, recognition of hypoglycemia, field management of trauma patients, use of oropharyngeal and nasopharyngeal airway, use of laryngeal mask airway, and optimal oxygen supply (median, 4; IQR, 3-4), but responded with low scores for most other questions. Based on the EMS provider certification, nurses scored themselves more proficient than level-1 emergency medical technicians (EMTs) for intravenous access (P<0.001), whereas level-1 EMTs recognized themselves more proficient than nurses for endotracheal intubation (P<0.001), use of Magill forceps (P=0.004), and pediatric cardiopulmonary resuscitation (P<0.001). Conclusion This study recognized the discrepancies in the perception of EMS provider’s field skill proficiency, as perceived by EMS providers and medical directors, and between level-1 EMTs and nurses. We propose that regional EMS authorities need to make persistent efforts to narrow these perception gaps through effective educational programs for EMS providers and medical directors.

BACKGROUND: Prophylaxis for hepatitis B virus (HBV) recurrence is essential after liver transplantation (LT) in HBV-associated recipients. This study established an individualized HBV prophylaxis protocol, through optimization of hepatitis B immunoglobulin (HBIG) administration, with application of simulative half-life (SHL). METHODS: This study involved five parts: Part 1 developed the SHL estimation method with 20 patients; Parts 2 and 3 assessed the SHL variability and developed a simulation model to apply SHL in 100 patients; Part 4 validated the simulation model in 114 patients, and Part 5 was a cross-sectional study on the current status of HBIG infusion intervals in 660 patients. RESULTS: In Part 1, infusion of 10,000 IU HBIG induced add-on rise hepatitis B surface antibody (anti-HBs) titer of 5,252.5 ± 873.7 IU/L, which was 4.4% lower than actual measurement. Mean SHL of 20.0 ± 3.7 days was 2.2% longer than actual measurement. In Part 2, the medians of the intra- and inter-individual coefficient of variation in SHL were 13.5% and 18.5%, respectively. Pretransplant HBV DNA load and posttransplant antiviral therapy did not affect SHL. In Part 3, a simulation model was developed to determine the interval of HBIG infusion, by using SHL. In Part 4, all 114 patients were successfully managed with regular HBIG infusion intervals of ≥ 8 weeks, and the interval was prolonged to ≥ 12 weeks in 89.4%, with a target trough anti-HBs titer ≥ 200 IU/L. In Part 5, 47.4% of our patients received HBIG excessively, at a target trough titer of 500 IU/L. CONCLUSION: SHL estimation using only clinically available parameters seems to be reliably accurate when compared with actual measurements. We believe that SHL estimation is helpful to establish a personalized HBV prophylaxis protocol for optimizing HBIG administration.
Cross-Sectional Studies ; DNA ; Half-Life ; Hepatitis B virus ; Hepatitis B ; Hepatitis ; Humans ; Immunoglobulins ; Liver Transplantation ; Methods ; Recurrence