Purpose: Radiotherapy (RT) remains a cornerstone of curative treatment for localized and locally advanced prostate cancer. However, dose escalation to improve tumor control is often constrained by the proximity of the rectum, which increases the risk of gastrointestinal (GI) and genitourinary toxicities. Biodegradable rectal spacers inserted between the prostate and rectum have emerged as an effective approach to reduce rectal radiation exposure. This guideline provides evidence-based recommendations on indications, contraindications, procedural standards, and clinical management for biodegradable rectal spacer insertion during prostate cancer RT. Materials and Methods: This guideline was developed by a multidisciplinary expert panel through a systematic review of the literature, analysis of international guidelines (National Comprehensive Cancer Network, European Association of Urology, American Society for Radiation Oncology), and expert consensus among radiation oncologists, radiologists, and urologists with clinical experience in spacer insertion. The strength of each recommendation and the level of evidence were classified according to the modified GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system. Results: Spacer insertion is conditionally recommended (Grade C, Level I) for patients receiving definitive external-beam RT without rectal invasion. It reduces the high-dose rectal irradiation volume (V70–75) by >50%, decreases acute GI toxicity, and helps maintain bowel-related quality of life. However, the benefit for late severe toxicity (grade 2 or higher) remains debated in recent meta-analyses. Contraindications include rectal invasion, anatomical inaccessibility, infection, and material hypersensitivity. Procedures should be performed under local anesthesia in a sterile environment by trained physicians. Short-course antibiotics and simulator-based training, including completion of multiple supervised cases, are advised. Conclusion Biodegradable rectal spacer insertion is clinically validated and effective in reducing acute rectal toxicity. Although pivotal trials demonstrated a favorable procedural safety profile, real-world postmarket data include reports of rare but severe procedural complications. This guideline provides standardized recommendations tailored to Korean clinical practice while remaining consistent with international standards, emphasizing the importance of operator training and careful patient selection.

Purpose: We assessed the proportion of patients with a focal intrahepatic stricture (FIHS) that was a precursor lesion or malignancy and visualized only as a duct dilatation. Materials and Methods: This retrospective study assessed patients who underwent surgery or biopsy for an FIHS on CT or MRI between January 2010 and March 2022. The number and proportion of non-precursor benign lesions, precursors, and malignancies were calculated.Clinical variables and imaging features were compared between non-premalignant benign and premalignant/malignant FIHSs. Results: Twenty-eight patients with confirmed histopathological diagnoses were identified, including 15 men (54.0%) and 13 women (46.0%). The median age of all patients at the first imaging diagnosis was 65 ± 9.54 (range, 43–78) years. Of the 28 patients with FIHSs, 9 (32%) were diagnosed with cholangiocarcinoma and 7 (25%) were diagnosed with precursor lesions, which included six intraductal papillary neoplasms of the bile duct and one biliary intraepithelial neoplasm. Accordingly, 16 (57%) patients had malignant or precursor lesions, and 12 (43%) were diagnosed with non-precursor benign lesions. None of the clinical variables and imaging features used for analysis showed a statistically significant difference between the non-premalignant benign and premalignant/malignant FIHS groups (p > 0.05). Conclusion FIHSs visualized only as duct dilatation can harbor malignant or precursor lesions.

Objective: This study investigated the feasibility and prognostic relevance of threshold-based quantification of myocardial delayed enhancement (MDE) on CT in patients with nonischemic dilated cardiomyopathy (NIDCM). Materials and Methods: Forty-three patients with NIDCM (59.3 ± 17.1 years; 21 male) were included in the study and underwent cardiac CT and MRI. MDE was quantified manually and with a threshold-based quantification method using cutoffs of 2, 3, and 4 standard deviations (SDs) on three sets of CT images (100 kVp, 120 kVp, and 70 keV). Interobserver agreement in MDE quantification was assessed using the intraclass correlation coefficient (ICC). Agreement between CT and MRI was evaluated using the Bland-Altman method and the concordance correlation coefficient (CCC). Patients were followed up for the subsequent occurrence of the primary composite outcome, including cardiac death, heart transplantation, heart failure hospitalization, or appropriate use of an implantable cardioverter-defibrillator. The Kaplan–Meier method was used to estimate event-free survival according to MDE levels. Results: Late gadolinium enhancement (LGE) was observed in 29 patients (67%, 29/43), and the mean LGE found with the 5-SD threshold was 4.1% ± 3.6%. The 4-SD threshold on 70-keV CT showed excellent interobserver agreement (ICC = 0.810) and the highest concordance with MRI (CCC = 0.803). This method also yielded the smallest bias with the narrowest range of 95% limits of agreement compared to MRI (bias, -0.119%; 95% limits of agreement, -4.216% to 3.978%). During a median follow-up of 1625 days (interquartile range, 712–1430 days), 10 patients (23%, 10/43) experienced the primary composite outcome. Event-free survival significantly differed between risk subgroups divided by the optimal MDE cutoff of 4.3% (log-rank P = 0.005). Conclusion The 4-SD threshold on 70-keV monochromatic CT yielded results comparable to those of MRI for quantifying MDE as a marker of myocardial fibrosis, which showed prognostic value in patients with NIDCM.

Purpose: We assessed the proportion of patients with a focal intrahepatic stricture (FIHS) that was a precursor lesion or malignancy and visualized only as a duct dilatation. Materials and Methods: This retrospective study assessed patients who underwent surgery or biopsy for an FIHS on CT or MRI between January 2010 and March 2022. The number and proportion of non-precursor benign lesions, precursors, and malignancies were calculated.Clinical variables and imaging features were compared between non-premalignant benign and premalignant/malignant FIHSs. Results: Twenty-eight patients with confirmed histopathological diagnoses were identified, including 15 men (54.0%) and 13 women (46.0%). The median age of all patients at the first imaging diagnosis was 65 ± 9.54 (range, 43–78) years. Of the 28 patients with FIHSs, 9 (32%) were diagnosed with cholangiocarcinoma and 7 (25%) were diagnosed with precursor lesions, which included six intraductal papillary neoplasms of the bile duct and one biliary intraepithelial neoplasm. Accordingly, 16 (57%) patients had malignant or precursor lesions, and 12 (43%) were diagnosed with non-precursor benign lesions. None of the clinical variables and imaging features used for analysis showed a statistically significant difference between the non-premalignant benign and premalignant/malignant FIHS groups (p > 0.05). Conclusion FIHSs visualized only as duct dilatation can harbor malignant or precursor lesions.

Purpose: We assessed the proportion of patients with a focal intrahepatic stricture (FIHS) that was a precursor lesion or malignancy and visualized only as a duct dilatation. Materials and Methods: This retrospective study assessed patients who underwent surgery or biopsy for an FIHS on CT or MRI between January 2010 and March 2022. The number and proportion of non-precursor benign lesions, precursors, and malignancies were calculated.Clinical variables and imaging features were compared between non-premalignant benign and premalignant/malignant FIHSs. Results: Twenty-eight patients with confirmed histopathological diagnoses were identified, including 15 men (54.0%) and 13 women (46.0%). The median age of all patients at the first imaging diagnosis was 65 ± 9.54 (range, 43–78) years. Of the 28 patients with FIHSs, 9 (32%) were diagnosed with cholangiocarcinoma and 7 (25%) were diagnosed with precursor lesions, which included six intraductal papillary neoplasms of the bile duct and one biliary intraepithelial neoplasm. Accordingly, 16 (57%) patients had malignant or precursor lesions, and 12 (43%) were diagnosed with non-precursor benign lesions. None of the clinical variables and imaging features used for analysis showed a statistically significant difference between the non-premalignant benign and premalignant/malignant FIHS groups (p > 0.05). Conclusion FIHSs visualized only as duct dilatation can harbor malignant or precursor lesions.

BACKGROUND: Twin-to-twin transfusion syndrome (TTTS) is a serious complication of monochorionic twin pregnancies. It results from disproportionate blood supply to each fetus caused by abnormal vascular anastomosis within the placenta. Amniotic fluid (AF) is an indicator reflecting the various conditions of the fetus, and an imbalance in AF volume is essential for the antenatal diagnosis of TTTS by ultrasound. In this study, two different mass spectrometry quantitative approaches were performed to identify differentially expressed proteins (DEPs) within matched pairs of AF samples.METHODS: We characterized the AF proteome in pooled AF samples collected from donor and recipient twin pairs (n = 5 each) with TTTS by a global proteomics profiling approach and then preformed the statistical analysis to determine the DEPs between the two groups. Next, we carried out a targeted proteomic approach (multiple reaction monitoring) with DEPs to achieve high-confident TTTS-associated AF proteins.RESULTS: A total of 103 AF proteins that were significantly altered in their abundances between donor and recipient fetuses. The majority of upregulated proteins identified in the recipient twins (including carbonic anhydrase 1, fibrinogen alpha chain, aminopeptidase N, alpha-fetoprotein, fibrinogen gamma chain, and basement membrane-specific heparan sulfate proteoglycan core protein) have been associated with cardiac or dermatologic disease, which is often seen in recipient twins as a result of volume overload. In contrast, proteins significantly upregulated in AF collected from donor twins (including IgGFc-binding protein, apolipoprotein C-I, complement C1q subcomponent subunit B, apolipoprotein C-III, apolipoprotein A-II, decorin, alpha-2-macroglobulin, apolipoprotein A-I, and fibronectin) were those previously shown to be associated with inflammation, ischemic cardiovascular complications or renal disease.CONCLUSION: In this study, we identified proteomic biomarkers in AF collected from donor and recipient twins in pregnancies complicated by TTTS that appear to reflect underlying functional and pathophysiological challenges faced by each of the fetuses.