Background: Fractional flow reserve (FFR) based on computed tomography (CT) has been shown to better identify ischemia-causing coronary stenosis. However, this current technology requires high computational power, which inhibits its widespread implementation in clinical practice. This prospective, multicenter study aimed at validating the diagnostic performance of a novel simple CT based fractional flow reserve (CT-FFR) calculation method in patients with coronary artery disease. Methods: Patients who underwent coronary CT angiography (CCTA) within 90 days and invasive coronary angiography (ICA) were prospectively enrolled. A hemodynamically significant lesion was defined as an FFR ≤ 0.80, and the area under the receiver operating characteristic curve (AUC) was the primary measure. After the planned analysis for the initial algorithm A, we performed another set of exploratory analyses for an improved algorithm B. Results: Of 184 patients who agreed to participate in the study, 151 were finally analyzed.Hemodynamically significant lesions were observed in 79 patients (52.3%). The AUC was 0.71 (95% confidence interval [CI], 0.63–0.80) for CCTA, 0.65 (95% CI, 0.56–0.74) for CT-FFR algorithm A (P = 0.866), and 0.78 (95% CI, 0.70–0.86) for algorithm B (P = 0.112). Diagnostic accuracy was 0.63 (0.55–0.71) for CCTA alone, 0.66 (0.58–0.74) for algorithm A, and 0.76 (0.68–0.82) for algorithm B. Conclusion This study suggests the feasibility of automated CT-FFR, which can be performed on-site within several hours. However, the diagnostic performance of the current algorithm does not meet the a priori criteria for superiority. Future research is required to improve the accuracy.

Purpose: To evaluate the reliability and validity of the Cataract-related Visual Function Questionnaire (CVFQ). Methods: A prospective cross-sectional study of 141 cataract patients was conducted from March 2022 to June 2022. The questionnaire was created based on a literature review and advice from an expert panel. This study determined its construct validity, criterion validity, internal consistency, and test-retest reliability. Results: The CVFQ consists of 15 items distributed among five categories: overall visual quality, overall visual function, distance vision, near vision, and glare. In the exploratory factor analysis of validity, the first three principal components explained 77.8% of the variance. The p-values in the Spearman correlation test comparing the pre- and postoperative total CVFQ score and best-corrected visual acuity (BCVA) were 0.006 and 0.004, respectively. In the reliability analysis, Cronbach’s alpha was > 0.9 for internal consistency and the p-values of each subcategory were all significant in the analysis of test-retest reliability. Conclusions Our results indicate that the CVFQ is useful for measuring the visual quality and visual function of cataract patients in Korea.

Background: To ensure valid results of big data research in the medical field, the input laboratory results need to be of high quality. We aimed to establish a strategy for evaluating the quality of laboratory results suitable for big data research. Methods: We used Korean Association of External Quality Assessment Service (KEQAS) data to retrospectively review multicenter data. Seven measurands were analyzed using commutable materials: HbA1c, creatinine (Cr), total cholesterol (TC), triglyceride (TG), alpha-fetoprotein (AFP), prostate-specific antigen (PSA), and cardiac troponin I (cTnI). These were classified into three groups based on their standardization or harmonization status. HbA1c, Cr, TC, TG, and AFP were analyzed with respect to peer group values. PSA and cTnI were analyzed in separate peer groups according to the calibrator type and manufacturer, respectively. The acceptance rate and absolute percentage bias at the medical decision level were calculated based on biological variation criteria. Results: The acceptance rate (22.5%–100%) varied greatly among the test items, and the mean percentage biases were 0.6%–5.6%, 1.0%–9.6%, and 1.6%–11.3% for all items that satisfied optimum, desirable, and minimum criteria, respectively. Conclusions The acceptance rate of participants and their external quality assessment (EQA) results exhibited statistically significant differences according to the quality grade for each criterion. Even when they passed the EQA standards, the test results did not guarantee the quality requirements for big data. We suggest that the KEQAS classification can serve as a guide for building big data.

Objective: To investigate the relationship between reduced glutathione (GSH), a key molecule of the antioxidant defense system in the blood, and glutathione reductase (GR), which reduces oxidized glutathione (glutathione disulfide [GSSG]) to GSH and maintains the redox balance, with the prevalence of Alzheimer’s dementia and cognitive decline. Methods: In all, 20 participants with Alzheimer’s dementia who completed the third follow-up clinical evaluation over 6 years were selected, and 20 participants with normal cognition were selected after age and sex matching. The GSH and GR concentrations were the independent variables. Clinical diagnosis and neurocognitive test scores were the dependent variables indicating cognitive status. Results: The higher the level of GR, the greater the possibility of having normal cognition than of developing Alzheimer’s dementia. Additionally, the higher the level of GR, the higher the neurocognitive test scores. However, this association was not significant for GSH. After 6 years, the conversion rate from normal cognition to cognitive impairment was significantly higher in the lower 50th percentile of the GR group than in the upper 50th percentile. Conclusion The higher the GR, the lower the prevalence of Alzheimer’s dementia and incidence of cognitive impairment and the higher the cognitive test scores. Therefore, GR is a potential protective biomarker against Alzheimer’s dementia and cognitive decline.

Background/Aims: Three-dimensional cultures of human pancreatic cancer tissue also known as “organoids” have largely been developed from surgical specimens. Given that most patients present with locally advanced and/or metastatic disease, such organoids are not representative of the majority of patients. Therefore, we used endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) to collect pancreatic cancer tissues from patients with advanced pancreatic cancer to create organoids, and evaluated their utility in pancreatic cancer research. Methods: Single-pass EUS-FNA samplings were employed to obtain the tissue for organoid generation. After establishment of the organoid, we compared the core biopsy tissues with organoids using hematoxylin and eosin staining, and performed whole exome sequencing (WES) to detect mutational variants. Furthermore, we compared patient outcome with the organoid drug response to determine the potential utility of the clinical application of such organoid-based assays. Results: Organoids were successfully generated in 14 of 20 tumors (70%) and were able to be passaged greater than 5 times in 12 of 20 tumors (60%). Among them, we selected eight pairs of organoid and core biopsy tissues for detailed analyses. They showed similar patterns in hematoxylin and eosin staining. WES revealed mutations in KRAS, TP53, CDKN2A, SMAD4, BRCA1, and BRCA2 which were 93% homologous, and the mean nonreference discordance rate was 5.47%. We observed moderate drug response correlations between the organoids and clinical outcomes in patients who underwent FOLFIRINOX chemotherapy. Conclusions The established organoids from EUS-FNA core biopsies can be used for a suitable model system for pancreatic cancer research

Purpose: Adjuvant radiotherapy (RT) has been performed to reduce locoregional failure (LRF) following radical cystectomy for locally advanced bladder cancer; however, its efficacy has not been well established. We analyzed the locoregional recurrence patterns of post-radical cystectomy to identify patients who could benefit from adjuvant RT and determine the optimal target volume. Materials and Methods: We retrospectively reviewed 160 patients with stage ≥ pT3 bladder cancer who were treated with radical cystectomy between January 2006 and December 2015. The impact of pathologic findings, including the stage, lympho-vascular invasion, perineural invasion, margin status, nodal involvement, and the number of nodes removed on failure patterns, was assessed. Results: Median follow-up period was 27.7 months. LRF was observed in 55 patients (34.3%), 12 of whom presented with synchronous local and regional failures as the first failure. The most common failure pattern was distant metastasis (40%). Among LRFs, the most common recurrence site was the cystectomy bed (15.6%). Patients with positive resection margins had a significantly higher recurrence rate compared to those without (28% vs. 10%, p=0.004). The pelvic nodal recurrence rate was < 5% in pN0 patients; the rate of recurrence in the external and common iliac nodes was 12.5% in pN+ patients. The rate of recurrence in the common iliac nodes was significantly higher in pN2–3 patients than in pN0–1 patients (15.2% vs. 4.4%, p=0.04). Conclusion Pelvic RT could be beneficial especially for those with positive resection margins or nodal involvement after radical cystectomy. Radiation fields should be optimized based on the patient-specific risk factors.

Purpose: Adjuvant radiotherapy (RT) has been performed to reduce locoregional failure (LRF) following radical cystectomy for locally advanced bladder cancer; however, its efficacy has not been well established. We analyzed the locoregional recurrence patterns of post-radical cystectomy to identify patients who could benefit from adjuvant RT and determine the optimal target volume. Materials and Methods: We retrospectively reviewed 160 patients with stage ≥ pT3 bladder cancer who were treated with radical cystectomy between January 2006 and December 2015. The impact of pathologic findings, including the stage, lympho-vascular invasion, perineural invasion, margin status, nodal involvement, and the number of nodes removed on failure patterns, was assessed. Results: Median follow-up period was 27.7 months. LRF was observed in 55 patients (34.3%), 12 of whom presented with synchronous local and regional failures as the first failure. The most common failure pattern was distant metastasis (40%). Among LRFs, the most common recurrence site was the cystectomy bed (15.6%). Patients with positive resection margins had a significantly higher recurrence rate compared to those without (28% vs. 10%, p=0.004). The pelvic nodal recurrence rate was < 5% in pN0 patients; the rate of recurrence in the external and common iliac nodes was 12.5% in pN+ patients. The rate of recurrence in the common iliac nodes was significantly higher in pN2–3 patients than in pN0–1 patients (15.2% vs. 4.4%, p=0.04). Conclusion Pelvic RT could be beneficial especially for those with positive resection margins or nodal involvement after radical cystectomy. Radiation fields should be optimized based on the patient-specific risk factors.

Purpose: The Advanced Prostate Cancer Consensus Conference (APCCC) 2015 was based on topics withcontroversy in the field of advanced prostate cancer. To understand the Korean urologists perspective regardingthe issues, we have conducted a questionnaire named Prostate Cancer Summit (PCAS) 2016, with 9 importantsubtopics. Materials and Methods: Total 9 subtopics have been decided and questions were developed regarding eachsubtopic. The questions were based on that of APCCC 2015 and translated into Korean for better understanding.Total 51 panelists have voted online on 85 different questions. Results: The survey concluded that testosterone should be measured as a diagnostic criterion for castrationresistance prostate cancer (CRPC) and that consensus was reached on issues such as the use of androgenreceptor pathway inhibitors in the treatment of predocetaxel and postdocetaxel in CRPC patients. In addition,76% of the participants agreed that imaging tests were needed before new treatment in CRPC patients, anda majority of participants agreed that periodic imaging tests are necessary regardless of symptoms during treatmentfor CRPC. However, some issues, such as the use of prostate-specific antigen-based triggers for remediationin CRPC patients, the endocrine manipulation in nonmetastatic CRPC patients, and the onset of treatment inasymptomatic metastatic CRPC patients, were not agreed. Conclusions The results from PCAS 2016 has addressed some of the issues with controversy. Although thevoting results are subjective, it will help guide treatment decisions in topics with less evidence.

Background: s/Aims: Rebleeding of gastric varices (GVs) after endoscopic variceal obturation (EVO) can be fatal. This study was performed to evaluate the usefulness of computed tomography (CT) for the prediction of rebleeding after EVO GV bleeding. Methods: Patients who were treated with EVO for GV bleeding and underwent CT before and after EVO were included. CT images of the portal phase showing pretreatment GVs and feeding vessels, and nonenhanced images showing posttreatment cyanoacrylate impaction were reviewed. Results: Fifty-three patients were included. Their mean age was 60.6±11.6 years, and 40 patients (75.5%) were men. Alcoholic liver disease was the most frequent underlying liver disease (45.3%). Complete impaction of cyanoacrylate in GVs and feeding vessels were achieved in 40 (75.5%) and 24 (45.3%) of patients, respectively. During the follow-up, GV rebleeding occurred in nine patients, and the cumulative incidences of GV rebleeding at 3, 6, and 12 months were 11.8%, 18.9%, and 18.9%, respectively. The GV rebleeding rate did not differ significantly according to the complete cyanoacrylate impaction in the GV, while it differed significantly according to complete cyanoacrylate impaction in the feeding vessels. The cumulative incidences of GV rebleeding at 3, 6, and 12 months were 22.3%, 35.2%, and 35.2%, respectively, in patients with incomplete impaction in feeding vessels, and there was no rebleeding during the follow-up period in patients with complete impaction in the feeding vessels (p=0.002). Conclusions Abdominal CT is useful in the evaluation of the treatment response after EVO for GV bleeding. Incomplete cyanoacrylate impaction in feeding vessels is a risk factor for GV rebleeding.