1.Delayed Peripheral Facial Palsy after Acute Ischemic Stroke in the Territory of Anterior Inferior Cerebellar Artery
Sung Taek HWANG ; Jin Yong LEE ; Hyunbeom LEE ; Kyung Han KIM ; Hak Young RHEE
Journal of the Korean Neurological Association 2026;44(1):54-58
A 76-year-old male presented with dizziness and disequilibrium. Magnetic resonance imaging revealed an acute ischemic stroke in the left anterior inferior cerebellar artery (AICA) territory. Three days after admission the patient developed peripheral facial palsy with no radiological exacerbation of the infarction. He was managed with antiplatelet therapy and supportive care. Both the facial palsy and initial cerebellar symptoms resolved within 1 month. This case highlights delayed facial palsy as a rare presentation of AICA infarction.
2.Indirect comparison of perioperative outcomes between open, laparoscopic, and robotic pancreaticoduodenectomy: Systematic review and network meta-analysis
Janghun HAN ; Woohyung LEE ; Jung Bok LEE ; Taemin KIM ; Mirang LEE ; Minkyu SUNG ; Kwang Pyo HONG ; Seung Jae LEE ; Ki Byung SONG ; Jae Hoon LEE ; Dae Wook HWANG ; Song Cheol KIM
Annals of Hepato-Biliary-Pancreatic Surgery 2026;30(2):244-255
Background:
s/Aims: Pancreaticoduodenectomy (PD) is the standard treatment for periampullary tumors, but it is technically challenging. Evidence directly comparing open, laparoscopic, robotic, and hybrid approaches is limited. This study conducts a network meta-analysis (NMA) to compare the perioperative and oncologic outcomes of open PD (OPD), laparoscopic PD (LPD), robotic PD (RPD), and hybrid PD.
Methods:
We searched PubMed, EMBASE, and the Cochrane Library for studies published between January 1994 and August 2024.We included randomized controlled trials and comparative observational studies that evaluated at least two PD approaches. Perioperative outcomes were the primary endpoints, while oncologic safety served as a secondary endpoint. A random-effects NMA was performed, establishing treatment hierarchies through ranking probabilities (PROSPERO ID: CRD420250365864).
Results:
A total of 78 studies were included (5 randomized and 73 retrospective). RPD was associated with lower blood loss compared to OPD (mean difference [MD], –163.85 mL) and LPD (MD, –84.14 mL). Hospital stays were also shorter for RPD compared to OPD (MD, –2.50 days) and LPD (MD, –1.88 days). In contrast, OPD was the most time-efficient approach compared to LPD (MD, –77.61 minutes) and RPD (MD, –73.30 minutes). Mortality rates, severe complications, clinically relevant postoperative pancreatic fistula rates, and reoperation rates were comparable across all surgical approaches. In terms of oncologic safety, lymph node yield and R0 resection rates were similar for all modalities.
Conclusions
While OPD is the most time-efficient approach, RPD provides significant advantages in reducing intraoperative blood loss and shortening hospital stays compared to both LPD and OPD.
3.Key Measures for Evaluating Diagnostic Accuracy in Multi-Class Classification: An Overview and Simulation-Based Comparison
Leeha RYU ; Kyunghwa HAN ; Inkyung JUNG ; Yae Won PARK ; Sung Soo AHN ; Dosik HWANG
Korean Journal of Radiology 2026;27(4):344-355
Recent advancements in artificial intelligence have led to increased interest in predictive modeling across various domains, including medicine. Although numerous metrics have been established for binary classification, the growing adoption of multi-class systems necessitates robust evaluation measures. However, comprehensive simulation studies comparing the performance of existing multi-class metrics under diverse data conditions remain limited. In this study, we first provide a concise overview of commonly used accuracy metrics for multi-class classification. Then, we report a simulation study that systematically evaluates several diagnostic accuracy measures under a wide range of scenarios, including three- and five-class settings, balanced and imbalanced sample sizes, and different distributional assumptions for predictors. We assessed each metric’s performance in terms of bias and 95% confidence interval coverage. Under balanced conditions, most metrics demonstrated stable and unbiased performance, closely approximating the true values. However, under imbalanced conditions, greater bias was observed, with the M-index and polytomous discrimination index exhibiting comparatively more stable performance across various scenarios. The micro-averaged receiver operating characteristic curve area consistently showed higher bias under class imbalance. Finally, we applied these metrics to a glioma tumor grading task using external datasets. This study provides a systematic comparison of commonly used metrics and offers practical guidance for selecting appropriate measures in multi-class classification tasks.
4.Left Atrial Time-to-Peak From Time-Resolved MR Angiography as a Noninvasive Indicator of Left Atrial Pressure Before Catheter Ablation of Atrial Fibrillation
Jaemin SHIM ; Soojung PARK ; Yu-Whan OH ; Yun Gi KIM ; Jong-Il CHOI ; Sung Ho HWANG
Korean Journal of Radiology 2026;27(5):419-427
Objective:
To evaluate the performance of the left atrial time-to-peak (TTP) derived from time-resolved magnetic resonance angiography (TR-MRA) as a noninvasive indicator of left atrial pressure (LAP) in patients with atrial fibrillation (AF).
Materials and Methods:
This retrospective study included 92 patients who underwent cardiac TR-MRA and catheter-based LAP measurements prior to catheter ablation for AF between January 2021 and December 2022. TR-MRA–derived TTP was measured in the left atrium using contrast-enhanced time-signal intensity curves. Catheter-based LAP measured during sinus rhythm served as the reference standard, with high LAP defined as ≥15 mmHg. Univariable and multivariable linear regression analyses were performed, with LAP as the dependent variable and echocardiographic parameters as covariates. The diagnostic performance of TTP for high LAP was evaluated using receiver operating characteristic (ROC) curve analysis.
Results:
Among the 92 patients (mean age ± standard deviation, 60 ± 10 years; 70 male), 70 (76.0%) had low LAP, and 22 (23.9%) had high LAP. Mean TTP was significantly longer in patients with high LAP than in those with low LAP (25.1 ± 6.9 s vs.16.9 ± 5.7 s, P < 0.001). In multivariable linear regression analysis, TTP remained independently associated with LAP (β = 0.46, P < 0.001). ROC analysis demonstrated good discriminative performance of TTP for identifying high LAP, with an area under the curve of 0.834 (95% confidence interval, 0.742–0.904). Using a TTP cutoff of >19.6 seconds, the sensitivity and specificity for identifying elevated LAP levels were 81.8% (18/22) and 75.7% (53/70), respectively.
Conclusion
TR-MRA–derived TTP showed a significant independent association with invasively measured LAP. It may serve as a reliable noninvasive imaging marker for identifying high LAP in patients with AF undergoing catheter ablation.
5.Impact of Thyroid CT on Detecting Macroscopic Nodal Metastasis in Patients With Papillary Thyroid Microcarcinoma
Young Hun JEON ; Ji Ye LEE ; Taehyuk HAM ; Kyu Sung CHOI ; Inpyeong HWANG ; Roh-Eul YOO ; Koung Mi KANG ; Ji-hoon KIM
Korean Journal of Radiology 2026;27(5):484-494
Objective:
To evaluate the impact of adding CT to ultrasound (US) for nodal assessment in patients with papillary thyroid microcarcinoma (PTMC), particularly in those with US-node-negative disease.
Materials and Methods:
This single-center retrospective study included consecutive patients with PTMC (≤1 cm on US) who underwent both US and CT for PTMC staging between August 2016 and January 2020, and subsequently underwent surgery including neck dissection. The number of patients with clinical N1 and pathological N1 disease was assessed. The diagnostic performance of US, CT, and combined US + CT (positive if either was positive) for macroscopic lymph node metastasis (LNM) (i.e., metastatic tumor foci >2 mm) was evaluated. Cases with discordant nodal staging between US and CT were identified.The diagnostic utility of CT was also assessed in a subgroup of patients with node-negative findings on US.
Results:
Among 982 patients (mean age ± standard deviation, 47.3 ± 11.5 years; 774 female), pathological analysis confirmed cervical LNM in 377 patients, including macroscopic, microscopic, and size-unknown LNM in 187, 175, and 15 patients, respectively. The addition of CT to US improved sensitivity for detecting macroscopic LNM compared to US alone (68.4% [128/187] vs. 26.7% [50/187]; P < 0.001), while maintaining high specificity despite a significant decrease (90.9% [709/780] vs. 97.2% [758/780]; P < 0.001). Discordant nodal staging between US and CT regarding macroscopic LNM was observed in 149 cases (15.2% [149/982]), with 131 patients (87.9% [131/149]) being upstaged by CT. In patients with node-negative US findings, CT detected US-undetected macroscopic LNM in 78 patients (8.7% [78/895]) and exhibited a sensitivity of 56.9% (78/137) and specificity of 93.5% (709/758) for macroscopic LNM.
Conclusion
The integration of CT with US improved sensitivity for detecting macroscopic LNM in patients with PTMC, identifying those who would otherwise be inappropriately considered candidates for active surveillance based solely on US findings. This may assist in refining patient management.
6.Eligibility and causes of disqualification among living liver donor candidates: A single-center analysis of 991 candidates
Eun-Ju NAM ; Jong-Hyun KIM ; Hae-In SHIN ; Young-In YOON ; Deok-Bog MOON ; Ki-Hun KIM ; Tae-Yong HA ; Gi-Won SONG ; Dong-Hwan JUNG ; Gil-Chun PARK ; Shin HWANG ; Sung-Gyu LEE
Annals of Liver Transplantation 2026;6(1):17-24
Background:
A systematic evaluation of potential living liver donors is essential to ensure donor safety and optimize recipient outcomes in living donor liver transplantation (LDLT). This study aimed to assess donor acceptance rates and reasons for disqualification among individuals evaluated for LDLT at a high-volume transplant center over a one-year period.
Methods:
We retrospectively reviewed 1,087 potential living liver donors who presented for LDLT evaluation in 2023. Of these, 991 candidates advanced beyond the initial screening (Stage 1) and underwent comprehensive clinical, imaging, and pathological assessments (Stages 2 and 3). Candidates who discontinued after Stage 1 were excluded due to the absence of documented reasons for non-progression.
Results:
Among the 991 candidates who proceeded beyond initial screening, 473 (47.7%) completed the full donor evaluation, of whom 466 were judged to be suitable donors. Among suitable donors, 384 (82.4%) proceeded to donor hepatectomy, whereas 82 did not, primarily due to recipient-related factors such as clinical deterioration or withdrawal of consent. Donor ineligibility was determined in 422 candidates (42.6%), most commonly due to inadequate remnant liver volume (52.8%), hepatic steatosis (20.6%), and insufficient graft size (10.2%). Among candidates undergoing Stage 2 evaluation, 162 (16.3%) failed to meet steatosis criteria; 126 were excluded solely for steatosis and advised weight reduction, and 39 subsequently became eligible and successfully donated.
Conclusion
In this high-volume LDLT center, donor disqualification was primarily driven by remnant liver volume and hepatic steatosis. Targeted interventions such as weight reduction enabled successful donation in a subset of initially ineligible candidates, underscoring the importance of individualized donor evaluation and pre-donation optimization.
7.AFP-PIVKA-II score as a simplified quantifiable surrogate biomarker for hepatocellular carcinoma recurrence following living donor liver transplantation
Dae Hyeon WON ; Shin HWANG ; Chul-Soo AHN ; Deok-Bog MOON ; Tae-Yong HA ; Gi-Won SONG ; Dong-Hwan JUNG ; Gil-Chun PARK ; Woo-Hyoung KANG ; Young-In YOON ; Sung-Gyu LEE
Annals of Liver Transplantation 2026;6(1):25-32
Background:
We developed a simplified variant of the ADV score, the AFP-PIVKAII (AP) score for post-transplant hepatocellular carcinoma (HCC) prognosis, which considers only AFP and PIVKA-II levels excluding morphometric tumor size information from the ADV score. This study investigated the prognostic performance of the AP score in predicting HCC recurrence and overall survival (OS) after living donor liver transplantation (LDLT).
Methods:
We analyzed 843 patients with HCC who underwent LDLT between 2006 and 2015, assessing HCC recurrence and OS in relation to AP score.
Results:
The median pretransplant AFP and PIVKA-II levels were 12.8 ng/mL and 27 mAU/mL, respectively. The median and mean AP scores were 2.6 log (range: 0.6–9.2 log) and 2.9±1.1 log, respectively. The 5-year time-dependent area under the receiver operating characteristic curve for the AP score in predicting post-transplant HCC recurrence was 0.672 (p<0.001). HCC recurrence and OS curves along AP score intervals of 1.0 log showed statistical differences in accordance with the AP scores (both p<0.001). Using a Youden index J-derived AP score cutoff of 4.0 log, two-tiered groups (ADV <4.0 log vs. ADV ≥4.0 log) showed statistically significant differences in HCC recurrence and OS (both p<0.001). Harrell’s c-indices for AP score with cutoff of 4.0 log and ADV scores with cutoff of 5.0 log regarding HCC recurrence and OS were similar.
Conclusion
The AP score functions as an integrated surrogate marker for predicting post-transplant outcomes in patients with HCC undergoing LDLT. It may serve as a simplified alternative to the ADV score, particularly in patients with small HCCs.
8.A comparative analysis of surgical outcomes after robotic gastrectomy with conventional multiport, single-site, and single-port surgical system for gastric cancer
Ki-Yoon KIM ; Jawon HWANG ; Sung Hyun PARK ; Minah CHO ; Yoo Min KIM ; Woo Jin HYUNG ; Hyoung-Il KIM
Annals of Surgical Treatment and Research 2026;110(4):216-224
Purpose:
Technological advancements have enabled reduced-port robotic systems, enhancing the benefits of robotic surgery. This study compared the surgical outcomes of conventional multiport (5 ports), single-site (2 ports), and singleport (2 ports) robotic gastrectomy for gastric cancer.
Methods:
A prospectively collected database was retrospectively reviewed for patients who underwent robotic distal subtotal gastrectomy between January 2010 and August 2022 at Severance Hospital, Yonsei University Health System. The initial 20 cases from each group (multiport, single-site, and SP) were analyzed, focusing on demographics, surgical procedures, pathological results, and postoperative outcomes. The “textbook outcome” metric was employed to assess surgical quality.
Results:
The SP group showed lower visual analog pain scale compared to the multiport and single-site groups (3.5, 4.4, and 4.3, respectively, P = 0.017), faster time to first flatus (2.0, 2.7, and 2.8 days, respectively; P < 0.001), and shorter hospital stays (3.5, 6.2, and 5.5 days, respectively; P < 0.001). No significant differences were observed in major complications, unplanned intensive care unit care, readmission, or mortality between the groups. The rate of patients achieving textbook outcomes were 85.0% for the multiport group, 100% for the single-site group, and 95.0% for the SP group (P = 0.310).
Conclusion
Reduced-port robotic gastrectomy, including single-site and SP, has shown surgical safety with a high proportion of patients meeting textbook outcomes. The SP system demonstrated less pain and faster recovery, aligning with minimally invasive surgical goals. Therefore, the SP system could be a reliable and safe option for robotic gastrectomy, offering enhanced recovery without compromising surgical quality.
9.Development of an artificial intelligence-based prediction platform for early recurrence of resectable pancreatic cancer after curative surgery–toward future use as an indication for neoadjuvant treatment: a retrospective multicenter cohort study
So Jeong YOON ; Sung Hyun KIM ; Hongbeom KIM ; Sang Hyun SHIN ; Jin Seok HEO ; Seung Soo HONG ; Chang Moo KANG ; Kyung Sik KIM ; Ho Kyoung HWANG ; In Woong HAN
Annals of Surgical Treatment and Research 2026;110(2):76-83
Purpose:
Neoadjuvant treatment (NAT) is now the standard for borderline resectable pancreatic cancer (RPC) and is being considered for RPC. Early recurrence after curative surgery in RPC is often seen as a treatment failure, prompting considerations for NAT. Our goal was to develop an artificial intelligence (AI)-based predictive model utilizing preoperatively available factors to forecast early recurrences of resected RPC.
Methods:
This study included 469 patients who underwent surgery for RPC between 2011 and 2019. Clinicopathologic and oncologic data were retrospectively reviewed. Preoperative variables, including laboratory data and imaging findings, were collected. Early recurrence was defined as recurrence occurring within a year after surgery. Deep neural networks were then used to select variables by assessing their importance. A new model predicting early recurrence of RPC was subsequently developed.
Results:
Of the patients evaluated, 199 (42.4%) experienced early recurrence. The predictive model included 14 preoperative variables: CA 19-9, preoperative pancreatitis, serum albumin, platelet count, lymphocyte count, the American Society of Anesthesiologists physical status classification, tumor size, monocyte count, age, body mass index, CRP, hemoglobin, WBC count, and CEA. The area under the curve for the model was 0.786 in the training set and 0.734 in the test set.
Conclusion
We developed an AI-based model to predict the early recurrence of RPC using preoperative parameters. By identifying patients at risk of early recurrence, optimal individualized treatments such as NAT can be considered. Future prospective studies are crucial to establish clear indications for NAT in RPC.
10.Three-year outcomes of a prospective, multicenter study of rotational atherectomy with antirestenotic therapy for infrainguinal arterial disease
Sungsin CHO ; Hyung-Kee KIM ; Woo-Sung YUN ; Ui Jun PARK ; Sang Su LEE ; Jaehoon LEE ; Hong-Pil HWANG ; Jin Hyun JOH
Annals of Surgical Treatment and Research 2026;110(3):180-187
Purpose:
Atherosclerotic plaques in peripheral arterial disease (PAD) include fatty, mixed, and calcified types. Plaque burden is significantly associated with restenosis, reintervention, and amputation-free survival. Rotational and aspirational atherectomy (RAA) may effectively remove such plaques. This study aimed to evaluate long-term outcomes of RAA for infrainguinal PAD.
Methods:
Patients with infrainguinal lesions underwent revascularization using the Jetstream Atherectomy System (Boston Scientific). This 60-month extension assessed primary patency rate (PPR) and clinically driven target lesion revascularization (CD-TLR). Kaplan-Meier curves were used for survival analysis; P < 0.05 was considered statistically significant.
Results:
A total of 150 patients (mean age, 70.9 years; male, 86.0%; 65.4% with diabetes) were enrolled. The mean lesion length was 15.8 cm, with 74.0% occlusions and 47.3% severe calcification. Lesions were sclerotic (72.4%), thrombosclerotic (13.4%), thrombotic (9.4%), or in-stent (4.7%). A drug-coated balloon (DCB) was used in 85.5% of cases. PPR at 1, 3, and 5 years was 84.1%, 68.1%, and 58.5%, respectively. CD-TLR rates were 93.0%, 81.5%, and 67.4%, respectively. The benefit of DCB was sustained through 3 years but attenuated thereafter, highlighting the need for extended follow-up in infrainguinal interventions.
Conclusion
RAA demonstrated durable 5-year patency and safety outcomes. Device type, DCB use, lesion morphology, and calcium grade did not significantly influence long-term results. Lesion complexity remains the primary predictor of clinical outcome. Despite the complexity of infrainguinal lesions, the use of RAA demonstrated sustained patency through 3 years, with lesion complexity (particularly TASC classification) emerging as the most critical predictor of long-term success.

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