Background: Postoperative liver regeneration is essential for maintaining hepatic function. This study evaluated the rate, determinants, and volumetric patterns of early liver regeneration after hemihepatectomy. Methods: A retrospective review was conducted of 50 patients who underwent right or left hemihepatectomy between April 2019 and March 2025. Liver and spleen volumes (SV) were assessed preoperatively, at postoperative day (POD) 1 week, and at POD 3 months. Early liver regeneration rate (LRR) was defined as the percentage increase in remnant liver volume at POD 1 week relative to the preoperative future liver remnant (FLR), and patients were categorized into low (<50%) and high (≥50%) LRR groups. Clinical, biochemical, and volumetric variables were compared, and predictors of regeneration were identified using multivariable analyses. Regeneration patterns were also examined according to whether the FLR/standard liver volume (SLV) ratio was <50% or ≥50%. Results: FLR/SLV was the strongest independent predictor of rapid early liver regeneration (p<0.001). Remnants with FLR/SLV <50% exhibited rapid and sustained regeneration, whereas those with FLR/SLV ≥50% showed slower regrowth that plateaued after reaching approximately 90% of SLV. SV increased at POD 1 week in all patients; however, only the FLR/SLV ≥50% group showed a reduction by POD 3 months, whereas the <50% group maintained elevated volumes. Conclusions FLR/SLV reliably predicts early postoperative liver regeneration. Smaller remnants regenerate more rapidly, whereas persistent splenic enlargement suggests a sustained portal hemodynamic burden. Combined evaluation of FLR/SLV and SV may enhance perioperative risk assessment and surgical planning.

Purpose: Accurate identification of the bile duct bifurcation site is crucial in pure laparoscopic donor right hepatectomy (PLDRH) for living donor liver transplantation. This study aimed to develop and evaluate a deep learning model to predict the bile duct bifurcation site for surgical precision. Methods: We retrospectively analyzed 55 PLDRH procedures conducted between August 2021 and April 2022. A deep learning model combining UNet with a MiT-B3 encoder was trained on 150 manually annotated frames. We then incorporated expert-reviewed pseudo-labels from an additional 901 frames to refine the model. Performance was evaluated using 5-fold cross-validation and an independent test set. Results: Clinical evaluation showed a 97% accuracy in 5-fold cross-validation and 93.3% accuracy in the independent test set. From the initial to final model, dice similarity coefficient improved from 0.392 to 0.472, intersection over union from 0.279 to 0.339, and sensitivity from 0.487 to 0.643, while specificity remained consistent at 0.993. Conclusion The proposed artificial intelligence (AI) model demonstrated strong clinical performance in predicting the bile duct bifurcation site during PLDRH. Despite modest quantitative scores, the high clinical accuracy highlights the potential of integrating AI for precise donor hepatectomy.

Background: s/Aims: While large-for-size syndrome is uncommon in liver transplantation (LT), it can result in fatal outcome. To prevent such fatality, we manufactured 3D-printed intra-abdominal cavity replicas to provide intuitive understanding of the sizes of the graft and the patient’s abdomen in patients with small body size between July 2020 and February 2022. Methods: Clinical outcomes were compared between patients using our 3D model during LT, and patients who underwent LT without 3D model by using 1 : 5 ratio propensity score-matched analysis. Results: After matching, a total of 20 patients using 3D-printed abdominal cavity model and 100 patients of the control group were included in this study. There were no significant differences in 30-day postoperative complication (50.0% vs. 64.0%, p = 0.356) and the incidence of large-for-size syndrome (0% vs. 7%, p = 0.599). Overall survival of the 3D-printed group was similar to that of the control group (p = 0.665), but graft survival was significantly superior in the 3D-printed group, compared to the control group (p = 0.034). Conclusions Since it showed better graft survival, as well as low cost and short production time, our 3D-printing protocol can be a feasible option for patients with small abdominal cavity to prevent large-for-size syndrome after LT.

Background: s/Aims: While large-for-size syndrome is uncommon in liver transplantation (LT), it can result in fatal outcome. To prevent such fatality, we manufactured 3D-printed intra-abdominal cavity replicas to provide intuitive understanding of the sizes of the graft and the patient’s abdomen in patients with small body size between July 2020 and February 2022. Methods: Clinical outcomes were compared between patients using our 3D model during LT, and patients who underwent LT without 3D model by using 1 : 5 ratio propensity score-matched analysis. Results: After matching, a total of 20 patients using 3D-printed abdominal cavity model and 100 patients of the control group were included in this study. There were no significant differences in 30-day postoperative complication (50.0% vs. 64.0%, p = 0.356) and the incidence of large-for-size syndrome (0% vs. 7%, p = 0.599). Overall survival of the 3D-printed group was similar to that of the control group (p = 0.665), but graft survival was significantly superior in the 3D-printed group, compared to the control group (p = 0.034). Conclusions Since it showed better graft survival, as well as low cost and short production time, our 3D-printing protocol can be a feasible option for patients with small abdominal cavity to prevent large-for-size syndrome after LT.

Background: s/Aims: While large-for-size syndrome is uncommon in liver transplantation (LT), it can result in fatal outcome. To prevent such fatality, we manufactured 3D-printed intra-abdominal cavity replicas to provide intuitive understanding of the sizes of the graft and the patient’s abdomen in patients with small body size between July 2020 and February 2022. Methods: Clinical outcomes were compared between patients using our 3D model during LT, and patients who underwent LT without 3D model by using 1 : 5 ratio propensity score-matched analysis. Results: After matching, a total of 20 patients using 3D-printed abdominal cavity model and 100 patients of the control group were included in this study. There were no significant differences in 30-day postoperative complication (50.0% vs. 64.0%, p = 0.356) and the incidence of large-for-size syndrome (0% vs. 7%, p = 0.599). Overall survival of the 3D-printed group was similar to that of the control group (p = 0.665), but graft survival was significantly superior in the 3D-printed group, compared to the control group (p = 0.034). Conclusions Since it showed better graft survival, as well as low cost and short production time, our 3D-printing protocol can be a feasible option for patients with small abdominal cavity to prevent large-for-size syndrome after LT.

Background: Tacrolimus is a key immunosuppressant after liver transplantation.Although guideline-recommended trough levels are 4–10 ng/mL, concerns about nephrotoxicity, metabolic complications, and malignancies have led to interest in minimizing tacrolimus use. However, the effects of lower tacrolimus levels on graft rejection and hepatocellular carcinoma (HCC) recurrence remain unclear. Methods: We conducted a single-center, retrospective study of adult patients (≥19 years) who underwent living donor liver transplantation between January 2000 and December 2021. Patients were divided into low tacrolimus (FK) (<6 ng/mL) and high FK (≥6 ng/mL) groups based on tacrolimus levels measured 1–2 years post-transplantation. We analyzed overall survival, biopsy-proven rejection-free survival, and HCC recurrence-free survival in relevant subgroups. Cox proportional hazards regression identified predictors of mortality, rejection, and HCC recurrence. Results: Among 1,117 recipients, 941 were in the low FK group and 176 in the high FK group. Landmark analysis showed significantly better 10-year overall survival in the low FK group (82.8% vs. 68.8%, p=0.016), while rejection-free survival did not differ significantly beyond 2 years (p=0.098), despite early separation favoring the low FK group (p<0.001). Higher tacrolimus levels independently predicted increased mortality (hazard ratio [HR]=1.98, 95% confidence interval [CI] 1.35–2.89; p<0.001) and rejection (HR=2.20, 95% CI 1.48–3.27; p<0.001). Among 614 HCC patients, landmark analysis revealed no significant difference in recurrence-free survival (77.7% vs. 81.2%, p=0.288) or overall survival (77.3% vs. 65.8%, p=0.215), and FK levels were not independently associated with either outcome. Conclusion Maintaining tacrolimus levels below 6 ng/mL was associated with better survival and rejection outcomes without increasing HCC recurrence, suggesting dose minimization may be feasible in selected patients.

Purpose: This study aimed to determine whether micro-flow imaging (MFI) offers diagnostic performance comparable to that of contrast-enhanced ultrasonography (CEUS) in detecting segmental congestion among patients undergoing living donor liver transplantation (LDLT). Methods: Data from 63 patients who underwent LDLT between May and December 2022 were retrospectively analyzed. MFI and CEUS data collected on the first postoperative day were quantified. Segmental congestion was assessed based on imaging findings and laboratory data, including liver enzymes and total bilirubin levels. The reference standard was a postoperative contrast-enhanced computed tomography scan performed within 2 weeks of surgery. Additionally, a subgroup analysis examined patients who underwent reconstruction of the middle hepatic vein territory. Results: The sensitivity and specificity of MFI were 73.9% and 67.5%, respectively. In comparison, CEUS demonstrated a sensitivity of 78.3% and a specificity of 75.0%. These findings suggest comparable diagnostic performance, with no significant differences in sensitivity (P=0.655) or specificity (P=0.257) between the two modalities. Additionally, early postoperative laboratory values did not show significant differences between patients with and without congestion. The subgroup analysis also indicated similar diagnostic performance between MFI and CEUS. Conclusion MFI without contrast enhancement yielded results comparable to those of CEUS in detecting segmental congestion after LDLT. Therefore, MFI may be considered a viable alternative to CEUS.

Purpose: Right-sided tumors have been reported to have a poorer survival rate than left-sided tumors; however, there remains debate regarding whether sidedness is an independent prognostic factor in colorectal cancer liver metastasis (CRLM). This study aimed to assess the impact of sidedness on prognosis in resectable CRLM and to identify prognostic factors. Methods: Patients who underwent liver resection for CRLM at Samsung Medical Center from January 2008 to December 2021 were included in the investigation. Overall survival (OS) and progression-free survival (PFS) were analyzed, and prognostic factors were identified. Results: A total of 497 patients were included in the study, with 106 on the right side and 391 on the left side. The rightsided group had a higher percentage of synchronous tumors (90.6% vs. 80.3%, P = 0.020). In survival analysis, the right side showed lower 5-year OS (49.7% vs. 54.2, P = 0.305) and 5-year PFS (57.1% vs. 60.2%, P = 0.271), but the differences were not statistically significant. In the analysis of prognostic factors, synchronous tumor (odds ratio [OR], 5.01; P < 0.001), CEA (OR, 1.46; P = 0.016), and maximum tumor size of hepatic metastasis (OR, 1.09; P = 0.026) were associated with OS. Conclusion In resectable CRLM, there was no difference in prognosis based on sidedness. CEA level, synchronous tumor, and maximum tumor size of hepatic metastasis were identified as prognostic factors.

Purpose: This study aimed to determine whether micro-flow imaging (MFI) offers diagnostic performance comparable to that of contrast-enhanced ultrasonography (CEUS) in detecting segmental congestion among patients undergoing living donor liver transplantation (LDLT). Methods: Data from 63 patients who underwent LDLT between May and December 2022 were retrospectively analyzed. MFI and CEUS data collected on the first postoperative day were quantified. Segmental congestion was assessed based on imaging findings and laboratory data, including liver enzymes and total bilirubin levels. The reference standard was a postoperative contrast-enhanced computed tomography scan performed within 2 weeks of surgery. Additionally, a subgroup analysis examined patients who underwent reconstruction of the middle hepatic vein territory. Results: The sensitivity and specificity of MFI were 73.9% and 67.5%, respectively. In comparison, CEUS demonstrated a sensitivity of 78.3% and a specificity of 75.0%. These findings suggest comparable diagnostic performance, with no significant differences in sensitivity (P=0.655) or specificity (P=0.257) between the two modalities. Additionally, early postoperative laboratory values did not show significant differences between patients with and without congestion. The subgroup analysis also indicated similar diagnostic performance between MFI and CEUS. Conclusion MFI without contrast enhancement yielded results comparable to those of CEUS in detecting segmental congestion after LDLT. Therefore, MFI may be considered a viable alternative to CEUS.

Background: We aimed to identify the prognostic factors for late intrahepatic recurrence (IHR), defined as recurrence more than two years after curative treatment of newly diagnosed hepatocellular carcinoma (HCC). Methods: This retrospective cohort study included patients with newly diagnosed, previously untreated, very early, or early HCC treated with initial curative treatment and followed up without recurrence for more than two years, excluding early IHR defined as recurrence within two years in single center. Late IHR-free survival (IHRFS) was defined as the time interval from initial curative treatment to the first IHR or death without IHR, whichever occurred first. Results: Among all the enrolled 2,304 patients, 1,427 (61.9%) underwent curative intent hepatectomy and the remaining 877 (38.1%) underwent local ablative therapy (LAT). During the follow-up after curative treatment (median, 82.6 months; range, 24.1 to 195.7), late IHR was detected in 816 (35.4%) patients. In the multivariable analysis, age, male sex, cirrhotic liver at diagnosis, type of initial treatment, and modified albumin-bilirubin (mALBI) grade were significant prognostic baseline factors. Furthermore, mALBI grade at three (2a vs. 1, P = 0.02, hazard ratio [HR], 1.33; 95% confidence interval [CI], 1.04–1.70; 2b/3 vs. 1, P = 0.03; HR, 1.42; 95% CI, 1.03–1.94) and six months (2b/3 vs. 1; P = 0.006; HR, 1.61; 95% CI, 1.13–2.30) after initial curative treatment was also a significant prognostic factor for late IHR. Conclusion After curative treatment for newly diagnosed early HCC, the mALBI grade at three and six months after initial curative treatment, as well as at baseline, was one of the most crucial prognostic factors for late IHR.