Purpose: To characterize the electromagnetic (EM) behavior of a monopole and dipole hybrid (MDH) antenna and evaluate its performance relative to monopole and dipole antennas for 10.5 tesla (T) magnetic resonance imaging (MRI) applications. Materials and Methods: Full-wave EM simulations were performed to model an inductor-shortened 20-cm dipole and an MDH antenna with asymmetric 9-cm and 12-cm poles. Single elements and 16-channel arrays were arranged on cylindrical formers (inner diameter 25 cm) around a tissue-mimicking phantom (εr = 49, σ = 0.6 S/m, diameter = 18 cm, height = 30 cm) with ~4 cm inter-element spacing and no additional decoupling circuitry. The eight-channel monopole antenna and MDH arrays were further modeled and analyzed with and without coaxial feed cables to assess cable-induced effects on magnetic (B) field distribution. Relative individual transmit field maps of the 8-channel monopole antenna and MDH arrays were acquired on a 10.5 T MRI system using a gradient echo (GRE) sequence (repetition time [TR] = 4000 ms, echo time [TE] = 3.0 ms, acquisition time [TA] = 7:48 ms, flip angle = 60°, field of view [FOV] = 354 × 354 mm3 , resolution = 3.0 × 1.5 × 3.0 mm3 ). Results: The MDH antenna demonstrated enhanced longitudinal B-field concentration and improved directivity compared with the dipole antenna element. Across the 8- and 16-channel arrays, the MDH structures consistently exhibited lower coupling, reducing S 21 by up to 10 dB relative to the monopole and dipole antenna arrays. Cable attachment significantly altered the MDH field patterns, reflecting dipole-like sensitivity to commonmode currents; however, appropriate cable management preserved field stability. Conclusion The MDH antenna provides intrinsic decoupling advantages and robust multichannel behavior without requiring additional decoupling circuitry. These characteristics make the MDH architecture a strong candidate for next-generation high-density arrays for ultra-high field MRI.

Purpose: To evaluate several hybrid multi-element configurations to enhance B1+ effi-ciency, defined as the transmit magnetic field generated by the radiofrequency (RF) coil normalized by the net input power, and spatial coverage for 10.5 tesla (T) human brain imaging. Materials and Methods: Finite-difference time-domain simulations were performed using an anatomically detailed human head model to assess circularly polarized B1+ fieldsgenerated by 8-channel loop, dipole antenna, and monopole and dipole hybrid antenna (MDH) arrays. These baseline designs were extended to 16-channel arrays combining loops with dipole antennas or MDHs and to interleaved MDH-based arrays incorporating axially displaced dipole or monopole antennas. Results: The 8-channel MDH array yielded the highest central B1+ efficiency, exceedingloop and dipole antenna arrays by 38.5% and 33.3%, respectively, but peripheral coverage remained limited. The 16-channel loop + dipole antenna and loop + MDH arrays improved overall B1+ efficiency by up to 28.9% relative to their 8-channel counterparts.Interleaved combined structure arrays further enhanced peripheral excitation and superior–inferior coverage, with the T-shaped monopole antenna + MDH configuration achieving a high central efficiency. Conclusion MDH-centered combined structure arrays effectively balance deep-field efficiency and peripheral coverage at 10.5 T. Interleaving monopole antenna-type elements beneath MDHs provides additional improvement and represents a promising design pathway for achieving more uniform excitation in 10.5 T brain imaging.

Purpose: To optimize B1+ (transmit magnetic field generated by radiofrequency coils) andspecific absorption ratio (SAR) efficiency for human head imaging at 10.5 tesla (T) with various 8-channel dipole antenna element arrays. Materials and Methods: Electromagnetic simulations were employed to model threedimensional arrays including 8-channel half-wave, fractionated, meander-ends, and inductor-shortened dipole antennas. The B1+ efficiency and SAR efficiency were evaluated using a cylindrical phantom and a human model for human head imaging. The B1+ efficiency, peak10 g SAR, and SAR efficiency values of different dipole antenna arrays, including inductorshortened dipole arrays with coaxial cables additionally, were summarized and compared for practical applications. Results: The inductor-shortened dipole antenna array demonstrated the highest SAR efficiency values among the arrays with cylindrical phantoms. In the human model, the fractionated dipole showed the highest B1+ efficiency values, whereas the inductor-shortened dipole antenna array exhibited superior SAR efficiency compared to the other dipole antenna arrays. Further, simulation data with and without coaxial cables indicated that the inductor-shortened dipole antenna array without cables exhibited a 9.2% higher B1+ efficiency and 14.6% lower peak 10 g SAR than the array with cables. Consequently,the SAR efficiency of the inductor-shortened dipole antenna array without coaxial cables was 14.9% higher than that with coaxial cables. Conclusion The inductor-shortened dipole antenna array demonstrated higher SAR efficiency with low SAR values for human brain imaging at 10.5 T. Consequently, the optimization of the coaxial cable setup further enhanced its suitability for ultra-high field applications.

Purpose: To explore the signal-to-noise ratio (SNR) of loops and sleeve antennas for human head imaging at 10.5 tesla. Materials and Methods: Simulated SNR maps were calculated using XFdtd with a resolution of 2 × 2 × 2 mm3 . The 3D CAD renderings of the loop and sleeve antennas with single- , three- , and five-channels were evaluated. Each loop coil had dimensions of 35 × 50 mm 2 , and the length of the individual sleeves was 180 mm, with an additional 70 mm for the required coaxial sleeve balun. All SNR maps were calculated using MATLAB. These base elements were evaluated in three-loop configurations aligned in the z-direction and compared with the same number of sleeve antenna arrays spaced 15 mm apart to achieve similar coverage. This comparison was further extended to the five-channel case for both loops and sleeve antennas in arrangements that could achieve similar overall imaging coverage. Results: The single-sleeve antenna demonstrated a 17% higher SNR in close proximity to the conductor compared to a loop. A boost in SNR performance was also observed with three- and five-channel sleeve antennas with a close gap (15 mm) between the elements, as indicated. Substantial SNR improvements were mostly associated with the peripheral gains achievable with closely coupled sleeve antennas in a high-density array arrangement. Conclusion The sleeve antenna concept supports high-density receiver antenna arrays.Due to the higher conductor density, it can result in a significant peripheral SNR gain.

Osteoporosis and osteoporotic fractures cause socioeconomic concerns, and medical system and policies appear insufficient to prepare for these issues in Korea, where the older adult population is rapidly increasing. Many countries around the world are already responding to osteoporosis and osteoporotic fractures by adopting fracture liaison service (FLS), and such an attempt has only begun in Korea. In this article, we introduce the operation methods for institutions implementing FLS and characteristics of services, and activities of the FLS Committee for FLS implementation in the Korean Society for Bone and Mineral Research. In addition, we hope that the current position statement will contribute to the implementation of FLS in Korea and impel policy changes to enable a multidisciplinary and integrated FLS operated under the medical system.

Extra-pulmonary neuroendocrine carcinoma is a rare and aggressive cancer. Although several biological and histological markers have been suggested as prognostic factors for this cancer, the prognostic importance of systemic inflammatory markers, including the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio, is unclear. This study aimed to evaluate the association between systemic inflammatory markers and the prognosis of extra-pulmonary neuroendocrine carcinoma. We retrospectively analyzed the clinical data of 85 patients with unresectable or metastatic extra-pulmonary neuroendocrine carcinoma who received platinum-based chemotherapy as first-line chemotherapy from August 2007 to November 2019. We used time-dependent receiver operating characteristic curve analysis to determine the cut-off values. The cut-off values for the neutrophil-lymphocyte ratio and platelet-lymphocyte ratio were 3.0 and 158.5, respectively. There was no significant difference in the Eastern Cooperative Oncology Group performance status score, Ki-67 index, or response to chemotherapy between groups. The high neutrophil-lymphocyte ratio group showed significantly worse overall survival (high vs. low, median 11.1 vs. 21.0 months, log-rank p=0.004) and shorter median progression-free survival, but the latter was not statistically significant. The high platelet-lymphocyte ratio group also showed significantly worse progression-free survival and overall survival than the low platelet-lymphocyte ratio group (high vs. low:median 5.6 vs. 9.8 months, log-rank p=0.047 and median 13.8 vs. 21.0 months, log-rank p=0.013, respectively). In multivariable analysis, a high neutrophil-lymphocyte ratio was an independent prognostic factor for overall survival. The neutrophil-lymphocyte ratio is a potent and readily available prognostic factor for extra-pulmonary neuroendocrine carcinoma.

Objectives: . We aimed to assess the genetic differences between cases of early-stage tongue cancer that were positive or negative for lymph node metastasis. Methods: . In total, 35 cases of tongue cancer with RNA sequencing data were enrolled in this study. The gene expression profile of the following two groups was compared: N0 group (T stage 1 or 2 with N0 stage) and N+ group (T stage 1 or 2 with N+ stage). Using the R and limma packages in the Bioconductor program, we extracted the differentially expressed genes (DEGs). Gene ontology and pathway enrichment analysis were performed using the Database for Annotation, Visualization and Integration Discovery (DAVID) online tool. Immune cell infiltration was analyzed using the CIBERSORT online program. Immunochemical staining of the cancer tissue was evaluated and The Cancer Genome Atlas (TCGA) data were analyzed to validate the identified DEGs. Results: . No significant differences were found in the infiltration of 22 types of immune cells. Among a total of 51 identified DEGs, 14 genes were significantly upregulated, while 37 genes were significantly downregulated (P<0.01; fold change >2). Pathway analysis revealed significant associations with the arachidonic acid metabolism-related pathway, calcium signaling, and the muscle contraction pathway. The following DEGs were the most significantly different between the two groups: DEFB4A, SPRR2B, DEFB103B, SPRR2G, DEFB4B, and FAM25A. TCGA data showed that DEFB4A and DEFB103B were more highly expressed in the N0 group than in the N+ group, although the difference did not achieve statistical significance. Immunochemical staining of cancer tissue revealed significantly higher expression of defensin in the N0 group. Conclusions . Defensin (DEFB4A, DEFB103B, DEFB4B) may be a novel biomarker for early regional metastasis in T1/2 tongue cancer.

Background/Aims: This study aimed to determine changes in endoscopist-driven sedation practices 5 years after the first nationwide survey in 2014 by the Korean Society of Gastrointestinal Endoscopy (KSGE). Methods: A 59-item survey covering current practices was electronically mailed to all members of the KSGE in 2019. Results: In total, 955 (12.8%) out of 7,486 questionnaires were returned. A total of 738 (77.7%) out of 955 respondents attended dedicated sedation education programs. The American Society of Anesthesiologists class was recorded by 464 (51.2%) out of 907 respondents. The recording rate was higher in respondents who completed sedation education (p=0.014) and worked in general or tertiary hospitals (p<0.001). Compared to that reported in the previous survey, the reported use of propofol was higher in 2019. The respondents had higher satisfaction scores for propofol-based sedation compared with midazolam monotherapy (p<0.001). The rates of oxygen supplementation (p<0.001) and oxygen saturation level monitoring (p<0.001) during sedative endoscopy were higher in 2019 than in the previous survey. A total of 876 (98.4%) out of 890 respondents reported a separate recovery bay, and 615 (70.5%) out of 872 respondents reported that personnel were assigned solely to the recovery bay. Conclusions Endoscopist-driven sedation and monitoring practices in 2019 were significantly different than those in 2014. The respondents favored propofol-based sedation and utilized oxygen supplementation and monitoring of O2 saturation more frequently in 2019 than in 2014.

In 2020, the novel coronavirus disease 2019 (COVID-19) began to spread worldwide and remains an ongoing medical challenge. This case series reports on the clinical features and characteristics of patients with inflammatory bowel disease (IBD) and confirmed COVID-19 infection. From February 2020 to March 2021, nine patients with IBD had confirmed COVID-19 across four hospitals in Korea. The median age at COVID-19 diagnosis was 42 years. Six patients were male, and seven patients had ulcerative colitis (UC). No patients required oxygen therapy, intensive care unit hospitalizations, or died. The most common symptom was fever, and gastrointestinal (GI) symptoms developed as diarrhea in five patients with UC. Oral steroids were used to combat UC aggravation in two patients. In this case series of nine IBD patients diagnosed with COVID-19 in Korea, the clinical presentation was predominately a mild respiratory tract infection. Most patients with UC developed new GI symptoms including diarrhea.

Neuroendocrine tumors (NETs) are a group of malignancies arising from neuroendocrine cells and frequently originate in the gastrointestinal tract and pancreas. Although curative resection is the main treatment for localized disease, systemic therapy is needed for relapsed or metastatic/unresectable gastroenteropancreatic NETs (GEP-NETs). Although there are several NET treatment guidelines from various countries, the geographical discrepancies between patient clinical characteristics, the regulatory approval status for therapeutic agents, and medical practices necessitate specific guidelines for Korean patients. We here provide a consensus review of the diagnosis, staging and systemic treatment of Korean GEP-NET patients. Systemic therapy options and the current Korean expert consensus on these treatments, including somatostatin analogs, targeted therapies such as everolimus and sunitinib, peptide receptor radionuclide treatments, and cytotoxic chemotherapies are addressed.