Ah Young Jung

Objectives: To evaluate the usefulness of transperineal ultrasonography (TPUS) for assessing the activity of perianal fistulas by exploring features associated with the magnetic resonance novel index for fistula imaging in Crohn's disease (MAGNIFI‐CD). Methods: This single‐center retrospective study included pediatric patients (age 1 week were excluded. Following US features were evaluated: location, longitudinal length of the fistula, extension, diameter perpendicular to longitudinal axis, branching, vascularity, abscess, dominant feature, and proctitis. Multivariable linear regression analysis was performed to identify US features associated with MAGNIFI‐CD score. Changes in TPUS features were compared between responder and non‐responder groups. Results: A total of 44 patients were included (median age [interquartile range], 14 [13–16] years, boys:girls, 36:8). Multivariable linear regression analysis showed that fistula length (regression coefficient [standard error], 1.48 [0.48]; p = .004) and vascularity (regression coefficient [standard error], 2.87 [1.00]; p = .007) on TPUS were associated with MAGNIFI‐CD score. In 25 patients with clinical follow‐up data, the extent of change in vascularity was significantly higher in the clinical responder group (change in vascularity treated as an ordinal variable, 0.94 ± 0.77 versus 0.11 ± 0.78; p = .02). Conclusion: TPUS, especially through measurement of fistula length and vascularity, is a feasible adjunct to pelvic MRI for evaluating the severity and monitoring the treatment response of perianal fistulas in pediatric patients with CD.

Purpose: This study evaluated the diagnostic performance of two-dimensional shear-wave elastography (2D SWE) for assessing allograft pathology in pediatric liver transplantation (LT) recipients, with subgroup analyses according to sonographic approach and age group. Additionally, the present study aimed to identify factors associated with SWE-derived parameters.Methods: This study retrospectively analyzed pediatric LT recipients who had received a left lobe or left lateral segment graft during childhood and underwent paired 2D SWE and liver biopsy. Associations between elasticity and dispersion slope measurements and clinicopathologic parameters were evaluated using univariable and multivariable regression analyses. Subgroup analyses were performed according to sonographic approach and age group. Diagnostic performance was assessed using receiver operating characteristic analysis.Results: A total of 108 patients (median age, 13.4 years; 47 males) were included. Elasticity measured using the intercostal approach in patients aged ≥13 years showed significant associations with METAVIR (Meta-analysis of Histological Data in Viral Hepatitis) fibrosis grade, necroinflammatory activity grade, liver allograft fibrosis score, and rejection activity index score. In multivariable analysis incorporating clinical parameters, METAVIR fibrosis grade remained the only independent predictor of intercostal elasticity in this age group (coefficient, 2.17; P<0.001). Intercostal elasticity demonstrated excellent diagnostic performance for distinguishing F0–F2 from F3–F4 fibrosis (area under the curve [AUC], 0.95; P<0.001; cut-off, 11.0 kPa) and good performance for distinguishing F0–F1 from F2–F4 fibrosis (AUC, 0.83; P<0.001; cut-off, 7.2 kPa). In contrast, subcostal measurements and dispersion slope showed no significant association with any pathologic parameter.Conclusion: Intercostal elasticity demonstrated diagnostic value for predicting graft fibrosis in pediatric LT recipients aged ≥13 years who received left lobe or left lateral segment grafts. Among the evaluated clinicopathologic parameters, METAVIR fibrosis grade was the only independent predictor of elasticity in this subgroup.

Song JM, et al. Korean J Radiol. 2026 Jun;27(6):568-577. https://doi.org/10.3348/kjr.2025.1221

A regression model that incorporated sex, height, and weight accurately predicted normative liver and spleen volumes in a pediatric population.

Gadolinium-based contrast agent–associated adverse reaction rates in children undergoing contrast-enhanced MRI were low for acute physiologic reactions, acute allergic-like reactions, and delayed reactions, with no nephrogenic systemic fibrosis reported.

Seong Y, et al. Korean J Radiol. 2025 Oct;26(10):986-997. https://doi.org/10.3348/kjr.2025.0263

Purpose: The aim of this study was to evaluate diagnostic accuracy and to establish computed tomography (CT) and Doppler ultrasonography (US) criteria for hepatic outflow obstruction after pediatric liver transplantation (LT) using left lobe (LL) or left lateral section (LLS) grafts.Methods: Pediatric patients who underwent LT using LL or LLS grafts between January 1999 and December 2021 were retrospectively included. The diagnostic performance of Doppler US and CT parameters for hepatic outflow obstruction was calculated using receiver operating characteristic (ROC) curve analysis. A diagnostic decision tree model combining the imaging parameters was developed.Results: In total, 288 patients (150 girls; median age at LT, 1.8 years [interquartile range, 0.9 to 3.6 years]) were included. Among the Doppler US parameters, venous pulsatility index (VPI) showed excellent diagnostic performance (area under the ROC curve [AUROC], 0.90; 95% confidence interval [CI], 0.86 to 0.93; Youden cut-off value, 0.40). Among the CT parameters, anastomotic site diameter (AUROC, 0.92; 95% CI, 0.88 to 0.95; Youden cut-off, 4.2 mm) and percentage of anastomotic site stenosis (AUROC, 0.88; 95% CI, 0.84 to 0.92; Youden cut-off, 35%) showed excellent and good diagnostic performance, respectively. A decision tree model combining the VPI, peak systolic velocity, and percentage of anastomotic site stenosis stratified patients according to the risk of hepatic outflow obstruction.Conclusion: VPI, anastomotic site diameter, and percentage of anastomotic site stenosis were reliable imaging parameters for diagnosing hepatic outflow obstruction after pediatric LT using LL or LLS grafts.

Han MW, et al. Korean J Radiol. 2024 Sep;25(9):824-832. https://doi.org/10.3348/kjr.2024.0248

Jung AY. Brain Tumor Res Treat. 2024 Jan;12(1):1-13. https://doi.org/10.14791/btrt.2023.0037

We aimed to report the incidence and severity of nonionic low-osmolar iodine contrast medium (ICM)-related adverse drug reactions (ADRs) in the Republic of Korea, by analyzing data from our single tertiary institution and published Korean reports, and to determine whether there is a difference in the incidence of ICM-related ADR by ICM generics. A total of 1,161,419 consecutive contrast-enhanced computed tomography (CT) examinations between January 2016 and December 2021 at Asan Medical Center were included. A systematic search of the literature investigating the incidence of ICM-related ADR in the Republic of Korea published up to December 31, 2021 was performed. We pooled these outcomes with those of our study using a binomial-normal model, and the pooled incidences of ADRs were compared among ICM generics using chi-square tests. Seven studies with a total of 2,570,986 contrast-enhanced CT examinations from 12 institutions were included. The pooled incidences of overall, mild, moderate, and severe ICM-related ADRs in the Republic of Korea were 0.82% (95% CI: 0.61%–1.10%), 0.72% (95% CI: 0.50%–1.04%), 0.11% (95% CI: 0.08%–0.15%), and 0.013% (95% CI: 0.010%–0.018%), respectively. In multiple pairwise comparisons, there were no significant differences in the overall incidence of ADRs between ICM generics, except iomeprol versus iobitridol and iomeprol versus iohexol. For moderate and severe ADRs, there were no significant differences in ADR incidence between ICM generics. The incidence of moderate and severe ICM-related ADRs did not differ among ICM generics. Our results suggest that no restriction is required for selection among nonionic low-osmolar ICMs.