The global increase in obesity highlights the need for accurate tools to assess body composition and monitor treatment efficacy.Traditional metrics, including body mass index and waist circumference, offer limited precision for fat quantification. Imagingbased techniques capable of visualizing internal structures are increasingly being recognized for their ability to provide comprehensive fat assessment. This review outlines the principles, strengths, and limitations of key modalities, including dualenergy X-ray absorptiometry (DXA), CT, MRI, and bioelectrical impedance analysis (BIA). DXA is cost-effective and accessible for population-level screening, whereas CT and MRI offer higher precision, particularly for visceral fat assessment. BIA is a practical, low-cost alternative, but it is limited by variability and lack of standardization. Regulatory agencies, including the US Food and Drug Administration and the Korean Ministry of Food and Drug Safety, are increasingly supporting imaging-based endpoints in clinical trials of anti-obesity drugs because these methods capture fat mass reduction beyond total weight loss. Recent phase III trials of semaglutide and tirzepatide have underscored the utility of DXA and CT in quantifying fat loss and preserving lean mass. Selecting appropriate imaging modalities based on technical capabilities and regulatory considerations can improve the evaluation of obesity treatments and strengthen the design of anti-obesity drug trials.

Objective: To evaluate the accuracy and reasoning capabilities of large multimodal language models compared with those of neuroradiology subspecialty-trained radiologists in neuroradiology case interpretation. Materials and Methods: This experimental study used custom-made 401 radiologic quizzes derived from articles published in RadioGraphics covering neuroradiology and head and neck topics (October 2020 to February 2024). We prompted the GPT-4 Turbo with Vision (GPT-4V), GPT-4 Omni, Gemini Flash, and Claude models to provide the top three differential diagnoses with a rationale and describe examination characteristics such as imaging modality, sequence, use of contrast, image plane, and body part. The temperature was adjusted to 0 and 1 (T1). Two neuroradiologists answered the same questions.The accuracies of the large language models (LLMs) and the neuroradiologists were compared using generalized estimating equations. Three neuroradiologists assessed the rationale provided by the LLMs for their differential diagnoses using four-point scales, separately for specific lesion locations and imaging findings, and evaluated the presence of hallucinations and the overall acceptability of the responses. Results: Top-3 accuracy (i.e., correct answers present among top-3 differential diagnoses) of LLMs ranged from 29.9% (120 of 401) to 49.4% (198 of 401, obtained with GPT-4V in the T1 setting), while radiologists achieved 80.3% (322 of 401) and 68.3% (274 of 401), respectively (P < 0.001). Regarding the rationale for differential diagnoses, GPT-4V (T1) accurately identified both the specific lesion location and imaging findings in 30.7% (123 of 401) and 12.9% (16 of 124) of cases without textual clinical history. Hallucinations occurred in 4.5% (18 of 401), and only 29.4% (118 of 401) of the LLM-generated analyses were deemed acceptable. GPT-4V (T1) demonstrated high accuracy in identifying the imaging modality (97.4% [800 of 821]) and scanned body parts (92.2% [756 of 820]). Conclusion LLMs remarkably underperformed compared with neuroradiologists and showed unsatisfactory reasoning for their differential diagnoses, with performance declining further in cases without textual input of clinical history. These findings highlight the limitations of current multimodal LLMs in neuroradiological interpretation and their reliance on text input.

In patients with differentiated thyroid cancer (DTC), initial recurrence risk stratification based on clinical, histopathological, and perioperative data remains the key determinant for guiding management strategies during the first 1-2 years post-treatment. However, the adoption of ongoing risk stratification (ORS), which dynamically reassesses risk by integrating longitudinal clinical data and treatment response, enables more precise long-term prognostic assessment and facilitates highly individualized management. Building upon recent guidelines, the 2026 KTA guideline has been further refined by incorporating robust evidence from large-scale national cohorts and comprehensive systematic reviews. These updated recommendations outline contemporary concepts of ORS, risk-adapted TSH suppression targets, optimized surveillance modalities for recurrence detection, and disease-specific long-term follow-up strategies. Reflecting the paradigm shift toward de-escalated treatment, this revision integrates evolved perspectives on TSH suppression intensity, the clinical interpretation of thyroglobulin levels, and tailored follow-up intervals. These evidence-based recommendations aim to minimize unnecessary treatment and excessive surveillance in the large proportion of patients with excellent prognosis after initial therapy, while ensuring that each patient receives appropriately tailored and effective long-term management.

Thyroid cancer, one of the most common endocrine tumors, generally has a favorable prognosis but remains a significant medical and societal concern due to its high incidence. Early diagnosis and treatment of differentiated thyroid cancer (DTC) significantly affect long-term outcomes, requiring the selection and application of appropriate initial treatments to improve prognosis and quality of life. Recent advances in technology and health information systems have enhanced our understanding of the molecular genetics of thyroid cancer, facilitating the identification of aggressive subgroups and enabling the accumulation of research on risk factors through big data. The Korean Thyroid Association (KTA) has revised the “KTA Guidelines on the Management of Differentiated Thyroid Cancers 2024” to incorporate these advances, which were developed by a multidisciplinary team and underwent extensive review and approval processes by various academic societies. This article summarizes the 2024 KTA guidelines for nuclear medicine imaging in patients with DTC, written by the Nuclear Medicine members of the KTA Guideline Committee, and covers 18 F-FDG PET/CT and radioiodine imaging with SPECT/CT in the management of DTC. 

Thyroid cancer, one of the most common endocrine tumors, generally has a favorable prognosis but remains a significant medical and societal concern due to its high incidence. Early diagnosis and treatment of differentiated thyroid cancer (DTC) significantly affect long-term outcomes, requiring the selection and application of appropriate initial treatments to improve prognosis and quality of life. Recent advances in technology and health information systems have enhanced our understanding of the molecular genetics of thyroid cancer, facilitating the identification of aggressive subgroups and enabling the accumulation of research on risk factors through big data. The Korean Thyroid Association (KTA) has revised the “KTA Guidelines on the Management of Differentiated Thyroid Cancers 2024” to incorporate these advances, which were developed by a multidisciplinary team and underwent extensive review and approval processes by various academic societies.This article summarizes the 2024 KTA guidelines for radioactive iodine (RAI) therapy in patients with DTC, written by the Nuclear Medicine members of the KTA Guideline Committee, and covers RAI therapy as initial management of DTC and RAI therapy in advanced thyroid cancer.

Purpose: The novel curability criteria for elderly (EL) patients have been proposed to stratify their risk of lymph node metastasis (LNM), following non-curative endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). Hence, this study aimed to evaluate the effectiveness of the EL criteria and compare them with those of the well-known eCura system. Materials and Methods: A retrospective analysis was performed on 143 patients who did not meet the curative ESD criteria at a tertiary hospital in Korea between 2011 and 2022. Of these, 102 underwent additional surgery, while 41 were followed up without further treatment. The LNM rates based on the EL and eCura systems were stratified and compared. Results: In the surgery group, 29.4% (30/102) patients were classified as EL-low (EL-L) and 70.2% (72/102) as EL-high (EL-H). The LNM rates (95% confidence interval) were 0.0% (0.0–11.6) and 9.7% (4.0–19.0) for EL-L and EL-H, respectively (P=0.102). EL-L was closely aligned with the eCura low-risk category, with a similar patient proportion (32.4%) and an LNM rate of 0.0% (0.0–10.6). The eCura system classified 94.1% (48/51) of the EL-L patients as lowrisk, with an 86% concordance rate (123/143). Discordant cases included patients with positive vertical margins, but without other risk factors, who were classified as EL-H without LNM. Conclusions Patients with EL-L showed no LNM, and the EL criteria demonstrated high concordance with the eCura system. The EL criteria may be as effective as the eCura system in identifying low-risk patients after non-curative ESD for EGC.

Background: Periprosthetic fracture (PPF) is a troublesome complication as it utilizes substantial healthcare resources. Recent studies about the epidemiology of PPF after total knee arthroplasty (TKA) are still lacking, and there is limited national-level analysis focusing on the comorbid chronic conditions as risk factors of PPF. This study used national registry data from South Korea and aimed to investigate the epidemiology of PPF following TKA between 2010 and 2020 and identify which comorbidities contributed to the risk of PPF. Methods: Using Health Insurance Review and Assessment (HIRA) service data in South Korea, the incidence of PPF after TKA between 2010 and 2020 was evaluated and stratified by age and sex. Medical comorbidities were evaluated as possible risk factors for PPF using Cox regression analysis. Results: PPF occurred in 14,429 patients, accounting for 2.37% of total TKA patients. The prevalence of PPF by sex was 2.50% in women and 1.64% in men. The PPF rate was 2.82% in under 60 years, 2.25% in 60 to 69 years, 2.42% in 70 to 79 years, 2.29% in 80 to 89 years, and 2.12% in over 90 years. Among 17 analyzed comorbidities, 11 were found to be associated with PPF after TKA. Severe liver disease (hazard ratio [HR], 1.303), hemiplegia (HR, 1.244), and dementia (HR, 1.206) were the top 3 risk factors.Although osteoporosis, pulmonary disease, peptic ulcer, and diabetes showed relatively low HRs than these top 3 factors, the incidence rates were higher. Conclusions PPF occurred in 2.37% of TKA patients in South Korea from 2010 to 2020. PPF rate was higher in women. To prevent PPF after TKA, proper patient management and education should be emphasized, particularly in patients with severe liver disease, hemiplegia, and dementia.

Background: Periprosthetic fracture (PPF) is a troublesome complication as it utilizes substantial healthcare resources. Recent studies about the epidemiology of PPF after total knee arthroplasty (TKA) are still lacking, and there is limited national-level analysis focusing on the comorbid chronic conditions as risk factors of PPF. This study used national registry data from South Korea and aimed to investigate the epidemiology of PPF following TKA between 2010 and 2020 and identify which comorbidities contributed to the risk of PPF. Methods: Using Health Insurance Review and Assessment (HIRA) service data in South Korea, the incidence of PPF after TKA between 2010 and 2020 was evaluated and stratified by age and sex. Medical comorbidities were evaluated as possible risk factors for PPF using Cox regression analysis. Results: PPF occurred in 14,429 patients, accounting for 2.37% of total TKA patients. The prevalence of PPF by sex was 2.50% in women and 1.64% in men. The PPF rate was 2.82% in under 60 years, 2.25% in 60 to 69 years, 2.42% in 70 to 79 years, 2.29% in 80 to 89 years, and 2.12% in over 90 years. Among 17 analyzed comorbidities, 11 were found to be associated with PPF after TKA. Severe liver disease (hazard ratio [HR], 1.303), hemiplegia (HR, 1.244), and dementia (HR, 1.206) were the top 3 risk factors.Although osteoporosis, pulmonary disease, peptic ulcer, and diabetes showed relatively low HRs than these top 3 factors, the incidence rates were higher. Conclusions PPF occurred in 2.37% of TKA patients in South Korea from 2010 to 2020. PPF rate was higher in women. To prevent PPF after TKA, proper patient management and education should be emphasized, particularly in patients with severe liver disease, hemiplegia, and dementia.

Thyroid cancer, one of the most common endocrine tumors, generally has a favorable prognosis but remains a significant medical and societal concern due to its high incidence. Early diagnosis and treatment of differentiated thyroid cancer (DTC) significantly affect long-term outcomes, requiring the selection and application of appropriate initial treatments to improve prognosis and quality of life. Recent advances in technology and health information systems have enhanced our understanding of the molecular genetics of thyroid cancer, facilitating the identification of aggressive subgroups and enabling the accumulation of research on risk factors through big data. The Korean Thyroid Association (KTA) has revised the “KTA Guidelines on the Management of Differentiated Thyroid Cancers 2024” to incorporate these advances, which were developed by a multidisciplinary team and underwent extensive review and approval processes by various academic societies. This article summarizes the 2024 KTA guidelines for nuclear medicine imaging in patients with DTC, written by the Nuclear Medicine members of the KTA Guideline Committee, and covers 18 F-FDG PET/CT and radioiodine imaging with SPECT/CT in the management of DTC.