Rectal cancer, which accounts for approximately 40% of colorectal cancers, remains a major clinical concern. Recent advances in diagnostic imaging, surgical techniques, radiotherapy, and systemic treatment have steadily improved rectal cancer outcomes. Considering this, the Korean Rectal Cancer Multidisciplinary (KRCM) Committee has aimed to provide clinicians and policymakers with up-to-date, evidence-based clinical practice guidelines to support optimal decision-making, reflecting current evidence, the Korean healthcare context, and patient values and preferences. The Clinical Practice Guidelines for Rectal Cancer version 2.0 were developed through multidisciplinary collaboration with related academic societies, building upon and updating the KRCM Clinical Practice Guidelines version 1.0 (titled “Multidisciplinary guidelines for the management of rectal cancer”). These consensus guidelines of the KRCM were established based on a comprehensive literature review, evidence synthesis, with recommendation development guided by the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology, and consideration of applicability in real-world clinical practice under the national health insurance system. Each recommendation has been presented with its strength and level of evidence.

Background and Objectives: Among various emerging catheter-based treatments for severe tricuspid regurgitation (TR), the spacer device can reduce the regurgitation orifice without manipulating the valve leaflet. However, its clinical application has been hampered by traumatic anchoring to the myocardium and the coaxial alignment of the balloon resulting in insufficient TR reduction. This study aimed to evaluate the early-stage safety, technical feasibility, and preliminary efficacy of the novel atraumatic vertical spacer in patients with isolated severe TR. Methods: All procedures were guided by fluoroscopy and transthoracic echocardiography.The maximum device placement time with an inflated balloon was 24 hours. Changes in the amount of TR, right ventricular function, and patient hemodynamics were measured during balloon deployment. Results: A total of 7 patients (median age 74), underwent successful device implantation without procedure-related complications. During balloon inflation (median 25 minutes), there were no symptoms or signs indicative of TR intolerance. TR was reduced by 1 grade or greater in all patients, with 2 patients exhibiting a reduction of 3 grades, from torrential TR to a moderate degree. Mild TR after balloon inflation was achieved in 3 patients with baseline severe TR. The TR reduction observed during initial balloon deployment was sustained during the subsequent balloon maintenance period. Conclusions The Pivot-balloon procedure was safe, technically feasible, and effective in reducing TR in patients with severe TR. No periprocedural complications or adverse cardiovascular events were reported during device placement with TR reduction observed in all patients. However, longer-term follow-up is needed to confirm safety and treatment effect.

Background and Objectives: The Fractional Flow Reserve and Intravascular UltrasoundGuided Intervention Strategy for Clinical Outcomes in Patients with Intermediate Stenosis (FLAVOUR) trial demonstrated non-inferiority of fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) compared with intravascular ultrasound (IVUS)-guided PCI. We sought to investigate the cost-effectiveness of FFR-guided PCI compared to IVUS-guided PCI in Korea. Methods: A 2-part cost-effectiveness model, composed of a short-term decision tree model and a long-term Markov model, was developed for patients who underwent PCI to treat intermediate stenosis (40% to 70% stenosis by visual estimation on coronary angiography).The lifetime healthcare costs and quality-adjusted life-years (QALYs) were estimated from the healthcare system perspective. Transition probabilities were mainly referred from the FLAVOUR trial, and healthcare costs were mainly obtained through analysis of Korean National Health Insurance claims data. Health utilities were mainly obtained from the Seattle Angina Questionnaire responses of FLAVOUR trial participants mapped to EQ-5D. Results: From the Korean healthcare system perspective, the base-case analysis showed that FFR-guided PCI was 2,451 U.S. dollar lower in lifetime healthcare costs and 0.178 higher in QALYs compared to IVUS-guided PCI. FFR-guided PCI remained more likely to be cost-effective over a wide range of willingness-to-pay thresholds in the probabilistic sensitivity analysis. Conclusions Based on the results from the FLAVOUR trial, FFR-guided PCI is projected to decrease lifetime healthcare costs and increase QALYs compared with IVUS-guided PCI in intermediate coronary lesion, and it is a dominant strategy in Korea.

Background: Active surveillance (AS) has emerged as a viable management strategy for low-risk papillary thyroid microcarcinoma (PTMC), following pioneering trials at Kuma Hospital and the Cancer Institute Hospital in Japan. Numerous prospective cohort studies have since validated AS as a management option for low-risk PTMC, leading to its inclusion in thyroid cancer guidelines across various countries. From 2016 to 2020, the Multicenter Prospective Cohort Study of Active Surveillance on Papillary Thyroid Microcarcinoma (MAeSTro) enrolled 1,177 patients, providing comprehensive data on PTMC progression, sonographic predictors of progression, quality of life, surgical outcomes, and cost-effectiveness when comparing AS to immediate surgery. The second phase of MAeSTro (MAeSTro-EXP) expands AS to low-risk papillary thyroid carcinoma (PTC) tumors larger than 1 cm, driven by the hypothesis that overall risk assessment outweighs absolute tumor size in surgical decision-making. Methods: This protocol aims to address whether limiting AS to tumors smaller than 1 cm may result in unnecessary surgeries for low-risk PTCs detected during their rapid initial growth phase. By expanding the AS criteria to include tumors up to 1.5 cm, while simultaneously refining and standardizing the criteria for risk assessment and disease progression, we aim to minimize overtreatment and maintain rigorous monitoring to improve patient outcomes. Conclusion This study will contribute to optimizing AS guidelines and enhance our understanding of the natural course and appropriate management of low-risk PTCs. Additionally, MAeSTro-EXP involves a multinational collaboration between South Korea and Australia. This cross-country study aims to identify cultural and racial differences in the management of low-risk PTC, thereby enriching the global understanding of AS practices and their applicability across diverse populations.

Objective: The quantitative assessment of spinal cord volume is still in the early stages of development. Recently, normative morphometric values of the cervical spinal cord have been reported. This study aimed to establish normative values for spinal cord morphometry, extending beyond the cervical region to include the thoracic and lumbar spinal cord, and to examine the influence of sex and ethnicity on these measurements. Materials and Methods: This prospective study included 28 young, healthy, East Asian volunteers (14 males and 14 females;mean age, 30.14 ± 4.07 years) who underwent spinal cord MRI using a 3T scanner. The cross-sectional areas (CSAs), anteroposterior (AP) and transverse diameters, and compression ratios of the entire spinal cord were calculated. Additionally, the effects of sex and ethnicity on spinal cord volumetry were evaluated, with the influence of ethnicity assessed by comparing the findings with a Caucasian dataset from the PAM50 study. Results: The CSAs demonstrated two enlargements at the cervical and lumbar levels. The cervical enlargement at C4–5 exhibited an elliptical shape, while the lumbar enlargement at T12 appeared more circular. The CSAs and AP and transverse diameters of the spinal cords in males were significantly larger than that of females (P < 0.001). The spinal cord compression ratios in East Asians were significantly lower than those in Caucasians (P < 0.001). Conclusion This study revealed that the two spinal cord enlargements exhibit different patterns and suggest significant differences in spinal cord morphometric values according to sex and ethnicity.

Objective: The quantitative assessment of spinal cord volume is still in the early stages of development. Recently, normative morphometric values of the cervical spinal cord have been reported. This study aimed to establish normative values for spinal cord morphometry, extending beyond the cervical region to include the thoracic and lumbar spinal cord, and to examine the influence of sex and ethnicity on these measurements. Materials and Methods: This prospective study included 28 young, healthy, East Asian volunteers (14 males and 14 females;mean age, 30.14 ± 4.07 years) who underwent spinal cord MRI using a 3T scanner. The cross-sectional areas (CSAs), anteroposterior (AP) and transverse diameters, and compression ratios of the entire spinal cord were calculated. Additionally, the effects of sex and ethnicity on spinal cord volumetry were evaluated, with the influence of ethnicity assessed by comparing the findings with a Caucasian dataset from the PAM50 study. Results: The CSAs demonstrated two enlargements at the cervical and lumbar levels. The cervical enlargement at C4–5 exhibited an elliptical shape, while the lumbar enlargement at T12 appeared more circular. The CSAs and AP and transverse diameters of the spinal cords in males were significantly larger than that of females (P < 0.001). The spinal cord compression ratios in East Asians were significantly lower than those in Caucasians (P < 0.001). Conclusion This study revealed that the two spinal cord enlargements exhibit different patterns and suggest significant differences in spinal cord morphometric values according to sex and ethnicity.

Objective: The quantitative assessment of spinal cord volume is still in the early stages of development. Recently, normative morphometric values of the cervical spinal cord have been reported. This study aimed to establish normative values for spinal cord morphometry, extending beyond the cervical region to include the thoracic and lumbar spinal cord, and to examine the influence of sex and ethnicity on these measurements. Materials and Methods: This prospective study included 28 young, healthy, East Asian volunteers (14 males and 14 females;mean age, 30.14 ± 4.07 years) who underwent spinal cord MRI using a 3T scanner. The cross-sectional areas (CSAs), anteroposterior (AP) and transverse diameters, and compression ratios of the entire spinal cord were calculated. Additionally, the effects of sex and ethnicity on spinal cord volumetry were evaluated, with the influence of ethnicity assessed by comparing the findings with a Caucasian dataset from the PAM50 study. Results: The CSAs demonstrated two enlargements at the cervical and lumbar levels. The cervical enlargement at C4–5 exhibited an elliptical shape, while the lumbar enlargement at T12 appeared more circular. The CSAs and AP and transverse diameters of the spinal cords in males were significantly larger than that of females (P < 0.001). The spinal cord compression ratios in East Asians were significantly lower than those in Caucasians (P < 0.001). Conclusion This study revealed that the two spinal cord enlargements exhibit different patterns and suggest significant differences in spinal cord morphometric values according to sex and ethnicity.

Background and Objectives: Among various emerging catheter-based treatments for severe tricuspid regurgitation (TR), the spacer device can reduce the regurgitation orifice without manipulating the valve leaflet. However, its clinical application has been hampered by traumatic anchoring to the myocardium and the coaxial alignment of the balloon resulting in insufficient TR reduction. This study aimed to evaluate the early-stage safety, technical feasibility, and preliminary efficacy of the novel atraumatic vertical spacer in patients with isolated severe TR. Methods: All procedures were guided by fluoroscopy and transthoracic echocardiography.The maximum device placement time with an inflated balloon was 24 hours. Changes in the amount of TR, right ventricular function, and patient hemodynamics were measured during balloon deployment. Results: A total of 7 patients (median age 74), underwent successful device implantation without procedure-related complications. During balloon inflation (median 25 minutes), there were no symptoms or signs indicative of TR intolerance. TR was reduced by 1 grade or greater in all patients, with 2 patients exhibiting a reduction of 3 grades, from torrential TR to a moderate degree. Mild TR after balloon inflation was achieved in 3 patients with baseline severe TR. The TR reduction observed during initial balloon deployment was sustained during the subsequent balloon maintenance period. Conclusions The Pivot-balloon procedure was safe, technically feasible, and effective in reducing TR in patients with severe TR. No periprocedural complications or adverse cardiovascular events were reported during device placement with TR reduction observed in all patients. However, longer-term follow-up is needed to confirm safety and treatment effect.

Background and Objectives: The Fractional Flow Reserve and Intravascular UltrasoundGuided Intervention Strategy for Clinical Outcomes in Patients with Intermediate Stenosis (FLAVOUR) trial demonstrated non-inferiority of fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) compared with intravascular ultrasound (IVUS)-guided PCI. We sought to investigate the cost-effectiveness of FFR-guided PCI compared to IVUS-guided PCI in Korea. Methods: A 2-part cost-effectiveness model, composed of a short-term decision tree model and a long-term Markov model, was developed for patients who underwent PCI to treat intermediate stenosis (40% to 70% stenosis by visual estimation on coronary angiography).The lifetime healthcare costs and quality-adjusted life-years (QALYs) were estimated from the healthcare system perspective. Transition probabilities were mainly referred from the FLAVOUR trial, and healthcare costs were mainly obtained through analysis of Korean National Health Insurance claims data. Health utilities were mainly obtained from the Seattle Angina Questionnaire responses of FLAVOUR trial participants mapped to EQ-5D. Results: From the Korean healthcare system perspective, the base-case analysis showed that FFR-guided PCI was 2,451 U.S. dollar lower in lifetime healthcare costs and 0.178 higher in QALYs compared to IVUS-guided PCI. FFR-guided PCI remained more likely to be cost-effective over a wide range of willingness-to-pay thresholds in the probabilistic sensitivity analysis. Conclusions Based on the results from the FLAVOUR trial, FFR-guided PCI is projected to decrease lifetime healthcare costs and increase QALYs compared with IVUS-guided PCI in intermediate coronary lesion, and it is a dominant strategy in Korea.

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder characterized by the presence of eosinophilic nuclear inclusions in neurons and somatic cells. It clinically manifests as cognitive decline, seizures, and autonomic dysfunction. A 44-year-old man presented with a transient visual field defect and hemiparesis. Based on characteristic imaging findings and pathological findings, NIID was suspected and diagnosed through genetic testing. This case emphasizes the importance of comprehensive clinical phenotype analysis and accurate genetic diagnosis.