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result(s) for
"Kwon, Heeyeon"
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Multimodal Large Language Models in Medical Imaging: Current State and Future Directions
by
Kim, Namkug
,
Kyung, Sunggu
,
Seo, Jinyoung
in
Artificial Intelligence
,
Connectors
,
Diagnostic Imaging - methods
2025
Multimodal large language models (MLLMs) are emerging as powerful tools in medicine, particularly in radiology, with the potential to serve as trusted artificial intelligence (AI) partners for clinicians. In radiology, these models integrate large language models (LLMs) with diverse multimodal data sources by combining clinical information and text with radiologic images of various modalities, ranging from 2D chest X-rays to 3D CT/MRI. Methods for achieving this multimodal integration are rapidly evolving, and the high performance of freely available LLMs may further accelerate MLLM development. Current applications of MLLMs now span automatic generation of preliminary radiology report, visual question answering, and interactive diagnostic support. Despite these promising capabilities, several significant challenges hinder widespread clinical adoption. MLLMs require access to large-scale, high-quality multimodal datasets, which are scarce in the medical domain. Risks of hallucinated findings, lack of transparency in decision-making processes, and high computational demands further complicate implementation. This review summarizes the current capabilities and limitations of MLLMs in medicine-particularly in radiology-and outlines key directions for future research. Critical areas include incorporating region-grounded reasoning to link model outputs to specific image regions, developing robust foundation models pre-trained on large-scale medical datasets, and establishing strategies for the safe and effective integration of MLLMs into clinical practice.
Journal Article
Safe and effective thrombolysis in free flap salvage: Intra-arterial urokinase infusion
by
Yoon, Sungyeon
,
Kim, Jun Hyeok
,
Jun, Young-Joon
in
Anticoagulants
,
Biology and Life Sciences
,
Blood clots
2023
Despite the high success rate in reconstruction using free tissue transfer, flap failure is often caused by microvascular thrombosis. In a small percentage of cases with complete flap loss, a salvage procedure is performed. In the present study, the effectiveness of intra-arterial urokinase infusion through the free flap tissue was investigated to develop a protocol to prevent thrombotic failure. The retrospective study evaluated the medical records of patients who underwent salvage procedure with intra-arterial urokinase infusion after reconstruction with free flap transfer between January 2013 and July 2019. Thrombolysis with urokinase infusion was administered as salvage treatment for patients who experienced flap compromise more than 24 hours after free flap surgery. Because of an external venous drainage through the resected vein, 100,000 IU of urokinase was infused into the arterial pedicle only into the flap circulation. A total of 16 patients was included in the present study. The mean time to re-exploration was 45.4 hours (range: 24–88 hours), and the mean quantity of infused urokinase was 69,688 IU (range: 30,000–100,000 IU). 5 cases presented with both arterial and venous thrombosis, while 10 cases had only venous thrombosis and 1 case had only arterial thrombosis; in a study of 16 patients undergoing flap surgery, 11 flaps were found to have survived completely, while 2 flaps experienced transient partial necrosis and 3 were lost despite salvage efforts. In other word, 81.3% (13 of 16) of flaps survived. Systemic complications, including gastrointestinal bleeding, hematemesis, and hemorrhagic stroke, were not observed. The free flap can be effectively and safely salvaged without systemic hemorrhagic complications using high-dose intra-arterial urokinase infusion within a short period of time without systemic circulation, even in delayed salvage cases. Urokinase infusion results in successful salvage and low rate of fat necrosis.
Journal Article
The originating pattern of deep inferior epigastric artery: anatomical study and surgical considerations
2018
PurposeStudies focusing on the originating patterns of the deep inferior epigastric artery (DIEA) have not been conducted. Here, we analyzed the vascular anatomy of the DIEA with computed tomographic angiography (CTA) to provide assistance during proximal pedicle dissection of a DIEA-based flap.MethodsWe conducted a retrospective study on patients who had undergone breast reconstruction with the transverse rectus abdominis musculocutaneous flap and the deep inferior epigastric perforator flap from March 2006 to October 2016. Preoperative three-dimensional computed tomographic angiograms of the abdominal wall (hemi-abdominal walls) were employed in this study, and three independent surgeons reviewed all CTA images. The originating angles and the distance from the originating point to the DIEA turning point were analyzed. Moreover, we assessed the relationship between the measured values and patients’ characteristics, such as abdominal surgery history.ResultsCTA data of 184 patients and 368 hemiabdomens were reviewed and analyzed. Most of the DIEAs originated from the external iliac artery in the medial direction, proceeded caudally, and curved in a cephalic direction. The average descending length was 11.29 mm. As the DIEA origin angle decreased (toward the caudal direction), the distance of the initial descent increased (r = 0.382, p < 0.01). In addition, the descending length was significantly larger (p < 0.01) in the operation group (12.22 mm) than in the non-operation group (9.86 mm).ConclusionsSurgeons should consider DIEA-originating patterns to ensure safe pedicle dissection during flap elevation.
Journal Article
\Good Robot!\: Efficient Reinforcement Learning for Multi-Step Visual Tasks with Sim to Real Transfer
by
Hager, Gregory D
,
Greene, Nicholas
,
Hundt, Andrew
in
Algorithms
,
Computer simulation
,
Grasping (robotics)
2020
Current Reinforcement Learning (RL) algorithms struggle with long-horizon tasks where time can be wasted exploring dead ends and task progress may be easily reversed. We develop the SPOT framework, which explores within action safety zones, learns about unsafe regions without exploring them, and prioritizes experiences that reverse earlier progress to learn with remarkable efficiency. The SPOT framework successfully completes simulated trials of a variety of tasks, improving a baseline trial success rate from 13% to 100% when stacking 4 cubes, from 13% to 99% when creating rows of 4 cubes, and from 84% to 95% when clearing toys arranged in adversarial patterns. Efficiency with respect to actions per trial typically improves by 30% or more, while training takes just 1-20k actions, depending on the task. Furthermore, we demonstrate direct sim to real transfer. We are able to create real stacks in 100% of trials with 61% efficiency and real rows in 100% of trials with 59% efficiency by directly loading the simulation-trained model on the real robot with no additional real-world fine-tuning. To our knowledge, this is the first instance of reinforcement learning with successful sim to real transfer applied to long term multi-step tasks such as block-stacking and row-making with consideration of progress reversal. Code is available at https://github.com/jhu-lcsr/good_robot .
ExermiR‐129‐3p Enhances Muscle Function by Improving Mitochondrial Activity Through PARP1 Inhibition
2025
Background Physical exercise has beneficial effects on various organs, including skeletal muscle. However, not all patients are capable of engaging in exercise to maintain muscle function, which underscores the importance of identifying molecular mechanisms of physical training that could lead to the discovery of exercise‐mimicking molecules. Methods This study sought to identify molecular mediators of exercise that could improve muscle function. We focused on the exercise‐induced microRNA (miR)‐129‐3p, investigating its role and effects on mitochondrial activity both in vivo and in vitro. The expression of miR‐129‐3p was analysed in skeletal muscle following exercise, and its downstream effects on the poly (ADP‐ribose) polymerase‐1 (Parp1)‐SIRT1‐PGC1α signalling pathway were elucidated. Functional studies were conducted using muscle‐specific overexpression of miR‐129‐3p in adult mice and intramuscular injection of AAV9‐miR‐129‐3p in obese mice to assess exercise capacity and muscle strength. Results Exercise was found to upregulate miR‐129‐3p in skeletal muscle (p < 0.05), which directly inhibits Parp1, a major NAD+‐consuming enzyme. This inhibition leads to increased NAD+ levels (p < 0.05), activating SIRT1 and subsequently reducing the acetylation of PGC1α, thereby enhancing mitochondrial function. Muscle‐specific overexpression of miR‐129‐3p in adult mice significantly enhanced exercise capacity (> 130%, p < 0.0001), while AAV9‐miR‐129‐3p injections ameliorated muscle weakness (twitch force, > 140%, p < 0.05; tetanic force, > 160%, p < 0.01) in obese mice. In human skeletal muscle myoblasts, miR‐129‐3p improved mitochondrial function via the PARP1‐SIRT1‐PGC1α signalling pathway. Conclusion Our findings suggest that miR‐129‐3p, induced by exercise, can mimic the beneficial effects of physical exercise. This highlights miR‐129‐3p as a potential therapeutic target for improving muscle health, especially in individuals unable to exercise.
Journal Article
GS Hip Nail versus Affixus Hip Fracture Nail for the Intramedullary Nailing of Intertrochanteric Fractures
by
Lee, Heeyeon
,
Hwang, Jihyo
,
Kwon, Seungcheol
in
Anesthesia
,
Clinical medicine
,
Equipment and supplies
2023
Background: Intertrochanteric fractures are a global health concern, especially in aging populations like the Republic of Korea. Surgical treatments like intramedullary nailing are preferred for their benefit. Various hip nails are used worldwide, each with unique features and challenges. This study aims to compare the GS hip nail with the Affixus hip fracture nail for the treatment of intertrochanteric fractures. Material and Methods: This retrospective study, conducted at a single center, included 179 patients who underwent intramedullary nailing for intertrochanteric fractures using the GS hip nail or the Affixus hip fracture nail. Excluding specific cases, 43 patients in the GS group and 46 in the Affixus group met the minimum 6-month follow-up criteria. Result: The GS group exhibited a significantly shorter mean operation time (43.26 min) compared to the Affixus group (51.11 min). Radiographically, both groups showed no significant differences in their reduction quality, tip, and apex distance (TAD), or Cleveland index in the immediate postoperative window. However, the GS group achieved a greater valgus reduction based on the contralateral femoral neck shaft angle (NSA). At 6 months post-operation, there were no significant differences in TAD or advancement and sliding distances. Complication rates were similar between the two groups, with no implant breakages. Clinical outcomes, as measured via mHHS and EQ-5D-5L, showed no significant differences. Despite a slightly higher implant cost, the GS group had a lower total hospital cost than the Affixus group, but this was not statistically significant. Conclusions: This study highlights the efficiency of the GS hip nail in reducing the operation time compared to the Affixus hip fracture nail with comparable radiologic and clinical outcomes. Further research with long-term follow-up and larger patient studies are needed to fully assess its effectiveness in improving patient outcomes in hip fracture treatment.
Journal Article
Association of Plasma Carotenoid and Malondialdehyde Levels with Physical Performance in Korean Adolescents
2022
Increased oxidative stress has been shown to lead to muscle damage and reduced physical performance. The antioxidant mechanism is most likely to reduce these relationships, but in the context of the action of carotenoids, more research is needed. This study aimed to investigate whether carotenoids modify the association between plasma malondialdehyde (MDA) and physical performance in Korean adolescents. The study sample consisted of 381 adolescents (164 boys, 217 girls) aged 13–18, who participated in the 2018 National Fitness Award Project. We quantified α-carotene, β-carotene, β-cryptoxanthin, lutein, zeaxanthin, lycopene, and MDA levels in plasma using HPLC with photodiode array detection. Among boys but not girls, plasma MDA level was negatively associated (β = −0.279, p = 0.0030) with total plasma carotenoid levels and marginally negatively associated (β = −0.907, p = 0.0876) with absolute hand grip strength. After adjustment for covariates in boys, the MDA level was negatively associated with absolute hand grip strength and relative hand grip strength; this association was observed only in groups with individual carotenoid and total carotenoid values below the median. These findings support a significant association between plasma MDA level and hand grip strength, and this association has been potentially modified by plasma levels of carotenoids in Korean male adolescents.
Journal Article
Renal involvement and favorable outcome in a child with mastocytosis
2020
Mastocytosis is a rare myeloproliferative disease in which mast cells abnormally accumulate in the skin, bone marrow, intestine, liver, spleen, and lymph nodes. Characterized by uncontrolled proliferation of aberrant mast cells, the disease can present either cutaneously or systemically. Mast cells facilitate the immune response and inflammation, and mastocytosis with renal involvement has been rarely reported in adults. Here, we describe a pediatric case of renal involvement in a patient with mastocytosis. A 12-year-old female with mastocytosis was admitted for edema, foamy urine, and gross hematuria. Initial laboratory findings showed azotemia, proteinuria, and hematuria. Renal biopsy findings were compatible with diffuse proliferative glomerulonephritis (DPGN). Immunofluorescence analysis of CD117 (c-Kit) staining resulted positive for rare infiltrating cells. These findings are unusual for primary glomerulonephritis (GN), and secondary GN is typically associated with mastocytosis. According to the literature, steroid treatment can be attempted in cases with renal disease associated with systemic mastocytosis. Therefore, the patient was treated with oral prednisolone, and proteinuria and hematuria disappeared after 4 months of treatment. After 5 months, prednisolone treatment was stopped, and the skin lesion improved. The renal function 22 months after prednisolone treatment was normal. This is a unique report of mastocytosis with DPGN in a child. c-Kit staining can be helpful for diagnosis, and the response to steroid treatment is favorable. Further study about the pathological relevance between mastocytosis and GN is necessary.
Journal Article
Clinical manifestations of BK virus infection in pediatric kidney transplant patients
2019
Background Polyomavirus BK (BKV) infection is an important cause of graft loss in kidney transplant patients. Purpose The purpose of this study was to evaluate clinical findings and risk factors for BKV in pediatric patients after kidney transplantation. Methods This retrospective single-center study included 31 pediatric kidney transplant recipients from January 2002 to December 2017. Two patients received 2 transplantations during the study period, and each transplant was analyzed independently. Total number of cases is 33 cases with 31 patients. BKV infection was confirmed from blood samples via periodic quantitative polymerase chain reaction. Results The mean age at kidney transplantation was 11.0±4.7 years, and the male-to-female ratio was 2.7:1. Three patients had a past medical history of high-dose chemotherapy and autologous stem-cell transplantation for solid tumors. Nine patients (27.3%) developed BKV infection. The median period from kidney transplantation to BKV detection in blood was 5.6 months. There was no statistically significant difference in estimated glomerular filtration rate between patients with and those without BKV infection. Among 9 patients with BKV viremia, 7 were treated by reducing their immunosuppressant dose, and BKV was cleared in 6 of these 7 patients. In the other 2 BKV-positive patients, viremia improved without immunosuppressant reduction. Conclusion BKV infection is common in children with kidney transplantation and might not have affected short-term renal function in our patient sample due to early immunosuppressant reduction at the time of BKV detection.
Journal Article
Post-vaccination Monitoring to Assess Foot-and-Mouth Disease Immunity at Population Level in Korea
2021
In South Korea, domestic cattle, pigs, and goats were subjected to mandatory foot-and-mouth disease (FMD) vaccination and year-round serosurveillance since 2011. In 2020, approximately USD 95 million was spent solely for FMD vaccine purchase for 59 million livestock, and 1.25 million samples were tested to estimate the population immunity and demonstrate the absence of virus circulation. As the FMD vaccination program was revised in 2018, the post-vaccination monitoring (PVM) was designed to evaluate the effectiveness of the vaccine program of three vaccines approved for routine use. To this end, monitoring post-vaccination immunity has been conducted by collecting 35,626 serum samples at 28 days post-vaccination following regular national vaccinations, which were carried out in April and in October in 2020. The design of the serological test for PVM was specially targeted at particular livestock groups, including dairy cattle, goats, and beef cattle aged 6–12 months, which were generally estimated to have a low expected seroprevalence. The risk factors had also been identified, considering the increased likelihood of infection in a particular location, herd size, and husbandry system applied in a targeted sample collection. Serum sample collection and SP-O and NSP antibody tests were performed by local veterinary laboratories using commercially available ELISAs. The current FMD vaccination program, which was performed twice a year following the regimen of primary vaccination and boost, resulted in over 80% population immunity. The seroprevalence monitored after the vaccination in fall was higher than the one studied in spring except in pigs. It was demonstrated that the seroprevalence of risk-based targeted samples ranged from 93.8 to 100% in cattle, 63.2 to 100% in pigs, and 20.0 to 100% in goats. Of note is the area near the North Korean borders which showed a relatively low seroprevalence among the targeted regions, and no NSP sero-positive reactor was detected in this region. When subpopulation immunity at the individual level was assessed, the seroprevalence in young cattle stock was slightly lower (95.8%) than that of adults (98.4%). In conclusion, the FMD vaccination campaign has been successfully implemented in Korea, and the PVM can be a supplementary program for massive routine surveillance in terms of providing timely information needed both to estimate population immunity and to properly target “risk-based surveillance.”
Journal Article