1.Imaging-Detected Extranodal Extension in Head and Neck Cancer: Current Evidence, Standardized Grading, and Clinical Implications
Jeong Hyun LEE ; Dongjun LEE ; Young Jun CHOI
Korean Journal of Radiology 2026;27(4):356-362
Extranodal extension (ENE) of metastatic lymph nodes is a well-established adverse prognostic factor in head and neck cancer and has traditionally been confirmed pathologically. Imaging-detected ENE (iENE) enables pre-treatment assessment and provides prognostic information across different treatment settings. Recent studies and meta-analyses have demonstrated an independent association between iENE and adverse outcomes in both nasopharyngeal carcinoma (NPC) and human papillomavirus–positive oropharyngeal carcinoma, supporting its prognostic relevance, particularly in nonsurgical patient populations in whom pathological confirmation is unavailable. Growing evidence supporting the prognostic impact of iENE has influenced recent revisions to the American Joint Committee on Cancer 9th edition staging system, which now incorporates “advanced radiological ENE” as a criterion for the N3 category in NPC. However, the clinical interpretation of iENE remains constrained by substantial interobserver variability, heterogeneous imaging criteria, and an imperfect correlation with pathological ENE (pENE), underscoring the ongoing debate regarding its clinical validity. Recent international efforts have sought to standardize imaging definitions and grading systems for iENE, with the aim of reducing variability and facilitating more consistent application in clinical practice and research. This review summarizes the current evidence regarding the prognostic and diagnostic roles of iENE, outlines recent developments in its classification, and discusses future directions for its integration into risk-adapted treatment planning for head and neck cancer.
2.Magnetic resonance imaging and management of suspected bilateral C2 hypertrophic ganglioneuritis in a Yorkshire Terrier dog: a case report
Dongjun KIM ; Hojung CHOI ; Youngwon LEE
Korean Journal of Veterinary Research 2025;65(1):e6-
A 6-year-old intact male Yorkshire Terrier, weighing 5.8 kg, presented with progressive ataxia of the thoracic and pelvic limbs with a four-month duration. A physical examination revealed proprioceptive ataxia and neck pain, with neurological signs indicating a C1–5 lesion. The radiographs revealed mild narrowing of the disc spaces at C2–3, C4–5, and C5–6, suggesting cervical intervertebral disc disease (IVDD). Magnetic resonance imaging (MRI) revealed bilateral symmetrical enlargement of the C2 nerve roots, causing spinal cord compression and distortion. The post-contrast T1-weighted images showed pronounced contrast enhancement, suggestive of hypertrophic ganglioneuritis. Mild disc protrusions at C4–5, C5–6, and C6–7 were also observed with minimal spinal compression, suggesting a lesser role in the clinical presentation. Considering the MRI findings, high-dose immunosuppressive prednisolone was administered under the tentative diagnosis of hypertrophic ganglioneuritis, leading to significant improvement in mobility and postural reactions. Follow-up MRI performed three months post-treatment revealed a significant decrease in the hypertrophy of the C2 nerve roots and alleviated spinal cord compression. This case underscores the essential role of MRI in differentiating hypertrophic ganglioneuritis from other spinal cord pathologies such as IVDD or spinal nerve tumors.
3.Medial Ankle Impingement Syndrome due to Talar Osteochondroma and Gout Attack: A Case Report
Min Gyu KYUNG ; Dongjun JEON ; Dong Yeon LEE
Journal of Korean Foot and Ankle Society 2024;28(1):31-35
Osteochondromas are benign bone tumors typically found in the metaphyseal region of long bones. These tumors are often asymptomatic and detected incidentally. However, their occurrence in atypical sites such as the talus can pose significant diagnostic and treatment challenges. This report describes a rare case of osteochondroma of the medial tubercle of the talus, which is an unprecedented location based on a review of relevant literature. A 28-year-old male presented with worsening medial ankle pain and limping. Imaging revealed a lesion consistent with osteochondroma contributing to medial ankle impingement syndrome. Uniquely, this case also featured a coinciding gout attack in the ankle joint. Surgical removal of the lesion resulted in significant symptom relief and functional improvement. This case underscores the need to consider rare diagnoses, such as talar osteochondroma, when presented with persistent medial ankle pain and highlights the potential presence of concurrent conditions, such as gout.
4.Correlation between fat signal fraction of vertebral body and intervertebral disc degeneration in dogs using magnetic resonance imaging
Seokmin LEE ; Arim LEE ; Jeongin CHOI ; Yu-Jung LEE ; Dongjun KIM ; Youngwon LEE ; Hojung CHOI
Journal of Veterinary Science 2024;25(6):e87-
Objective:
This study evaluated the relationship between IVD degeneration and the vertebral body FSF in dogs and compared these factors between chondrodystrophic (CD) and nonchondrodystrophic (NCD) dogs.
Methods:
IVD degeneration in dogs was classified morphologically using the Pfirrmann grade, and the vertebral body FSF was evaluated quantitatively.
Results:
The vertebral body FSF showed a statistically significant difference among the age groups. The vertebral body FSF was significantly higher in Pfirrmann grades 3–5 than in grades 1 and 2. The mean Pfirrmann grade of CD dogs was higher than that of NCD dogs in the four-to-six-year-old group. The mean vertebral body FSF of CD dogs was higher than that of NCD dogs in the group of seven years and above.
Conclusions
and Relevance: In dogs, the vertebral body FSF increased significantly with age and Pfirrmann grade. The CD dogs showed a higher degree of IVD degeneration at a younger age than the NCD dogs. CD dogs appeared to experience more severe fat deposition of the vertebral body in old age than NCD dogs. MRI examinations are helpful for evaluating IVD degeneration and vertebral body fat deposition.
5.Correlation between fat signal fraction of vertebral body and intervertebral disc degeneration in dogs using magnetic resonance imaging
Seokmin LEE ; Arim LEE ; Jeongin CHOI ; Yu-Jung LEE ; Dongjun KIM ; Youngwon LEE ; Hojung CHOI
Journal of Veterinary Science 2024;25(6):e87-
Objective:
This study evaluated the relationship between IVD degeneration and the vertebral body FSF in dogs and compared these factors between chondrodystrophic (CD) and nonchondrodystrophic (NCD) dogs.
Methods:
IVD degeneration in dogs was classified morphologically using the Pfirrmann grade, and the vertebral body FSF was evaluated quantitatively.
Results:
The vertebral body FSF showed a statistically significant difference among the age groups. The vertebral body FSF was significantly higher in Pfirrmann grades 3–5 than in grades 1 and 2. The mean Pfirrmann grade of CD dogs was higher than that of NCD dogs in the four-to-six-year-old group. The mean vertebral body FSF of CD dogs was higher than that of NCD dogs in the group of seven years and above.
Conclusions
and Relevance: In dogs, the vertebral body FSF increased significantly with age and Pfirrmann grade. The CD dogs showed a higher degree of IVD degeneration at a younger age than the NCD dogs. CD dogs appeared to experience more severe fat deposition of the vertebral body in old age than NCD dogs. MRI examinations are helpful for evaluating IVD degeneration and vertebral body fat deposition.
6.Correlation between fat signal fraction of vertebral body and intervertebral disc degeneration in dogs using magnetic resonance imaging
Seokmin LEE ; Arim LEE ; Jeongin CHOI ; Yu-Jung LEE ; Dongjun KIM ; Youngwon LEE ; Hojung CHOI
Journal of Veterinary Science 2024;25(6):e87-
Objective:
This study evaluated the relationship between IVD degeneration and the vertebral body FSF in dogs and compared these factors between chondrodystrophic (CD) and nonchondrodystrophic (NCD) dogs.
Methods:
IVD degeneration in dogs was classified morphologically using the Pfirrmann grade, and the vertebral body FSF was evaluated quantitatively.
Results:
The vertebral body FSF showed a statistically significant difference among the age groups. The vertebral body FSF was significantly higher in Pfirrmann grades 3–5 than in grades 1 and 2. The mean Pfirrmann grade of CD dogs was higher than that of NCD dogs in the four-to-six-year-old group. The mean vertebral body FSF of CD dogs was higher than that of NCD dogs in the group of seven years and above.
Conclusions
and Relevance: In dogs, the vertebral body FSF increased significantly with age and Pfirrmann grade. The CD dogs showed a higher degree of IVD degeneration at a younger age than the NCD dogs. CD dogs appeared to experience more severe fat deposition of the vertebral body in old age than NCD dogs. MRI examinations are helpful for evaluating IVD degeneration and vertebral body fat deposition.
7.Correlation between fat signal fraction of vertebral body and intervertebral disc degeneration in dogs using magnetic resonance imaging
Seokmin LEE ; Arim LEE ; Jeongin CHOI ; Yu-Jung LEE ; Dongjun KIM ; Youngwon LEE ; Hojung CHOI
Journal of Veterinary Science 2024;25(6):e87-
Objective:
This study evaluated the relationship between IVD degeneration and the vertebral body FSF in dogs and compared these factors between chondrodystrophic (CD) and nonchondrodystrophic (NCD) dogs.
Methods:
IVD degeneration in dogs was classified morphologically using the Pfirrmann grade, and the vertebral body FSF was evaluated quantitatively.
Results:
The vertebral body FSF showed a statistically significant difference among the age groups. The vertebral body FSF was significantly higher in Pfirrmann grades 3–5 than in grades 1 and 2. The mean Pfirrmann grade of CD dogs was higher than that of NCD dogs in the four-to-six-year-old group. The mean vertebral body FSF of CD dogs was higher than that of NCD dogs in the group of seven years and above.
Conclusions
and Relevance: In dogs, the vertebral body FSF increased significantly with age and Pfirrmann grade. The CD dogs showed a higher degree of IVD degeneration at a younger age than the NCD dogs. CD dogs appeared to experience more severe fat deposition of the vertebral body in old age than NCD dogs. MRI examinations are helpful for evaluating IVD degeneration and vertebral body fat deposition.
8.Computed Tomographic Features of Gallbladder Agenesis in a Golden Retriever
Yujung LEE ; Dongjun KIM ; Jeongin CHOI ; Youngwon LEE ; Hojung CHOI
Journal of Veterinary Clinics 2024;41(1):43-48
A two-year-old, intact female Golden Retriever had previously been diagnosed with a portosystemic shunt (PSS) during an ultrasonographic examination at a local animal hospital. The serum biochemistry revealed elevated liver enzymes and bile acid levels. The abdominal radiographic examination revealed mild serosal detail loss and microhepatica, while abdominal ultrasonography revealed mild ascites and high-velocity flow to the caudal vena cava (CVC) suspected as a PSS. The gallbladder was not observed within the hepatic parenchyma during ultrasonography. Computed tomography (CT) revealed an absent gallbladder and dilation of the common bile duct (CBD). Dilations of the gastroduodenal, splenic, colic and renal veins were also observed. A dilated left phrenico-abdominal vein that entered the CVC was previously misinterpreted as a PSS on the ultrasound examination. Based on the imaging examinations, the dog was diagnosed with congenital gallbladder agenesis associated CBD dilation.
9.Differential microbiota network according to colorectal cancer lymph node metastasis stages
Yeuni YU ; Donghyun HAN ; Hyomin KIM ; Yun Hak KIM ; Dongjun LEE
Journal of Genetic Medicine 2023;20(2):52-59
Purpose:
Colorectal cancer (CRC) is a common malignancy worldwide and the second leading cause of cancer-related deaths. In addition, lymph node metastasis in CRC is considered an important prognostic factor for predicting disease recurrence and patient survival. Recent studies demonstrated that the microbiome makes substantial contributions to tumor progression, however, there is still unknown about the microbiome associated with lymph node metastasis of CRC. Here, we first reported the microbial and tumor-infiltrating immune cell differences in CRC according to the lymph node metastasis status.
Materials and Methods:
Using Next Generation Sequencing data acquired from 368 individuals diagnosed with CRC (N0, 266; N1, 102), we applied the LEfSe to elucidate microbial differences. Subsequent utilization of the Kaplan-Meier survival analysis enabled the identification of particular genera exerting significant influence on patient survival outcomes.
Results
We found 18 genera in the N1 group and 3 genera in the N0 group according to CRC lymph node metastasis stages. In addition, we found that the genera Crenobacter (P=0.046), Maricaulis (P=0.093), and Arsenicicoccus (P=0.035) in the N0 group and Cecembia (P=0.08) and Asanoa (P=0.088) in the N1 group were significantly associated with patient survival according to CRC lymph node metastasis stages. Further, Cecembia is highly correlated to tumor-infiltrating immune cells in lymph node metastasized CRC.Concolusion: Our study highlights that tumor-infiltrating immune cells and intratumoral microbe diversity are associated with CRC. Also, this potential microbiome-based oncology diagnostic tool warrants further exploration.
10.Development of a Frailty Detection Model Using Machine Learning with the Korean Frailty and Aging Cohort Study Data
Dongjun KOO ; Ah Ra LEE ; Eunjoo LEE ; Il Kon KIM
Healthcare Informatics Research 2022;28(3):231-239
Objectives:
This paper aimed to use machine learning to identify a new group of factors predicting frailty in the elderly population by utilizing the existing frailty criteria as a basis, as well as to validate the obtained results.
Methods:
This study was conducted using data from the Korean Frailty and Aging Cohort Study (KFACS). The KFACS participants were classified as robust or frail based on Fried’s frailty phenotype and excluded if they did not properly answer the questions, resulting in 1,066 robust and 165 frail participants. We then selected influential features through feature selection and trained the model using support vector machine, random forest, and gradient boosting algorithms with the prepared dataset. Due to the imbalanced distribution in the dataset with a low sample size, holdout was applied with stratified 10-fold and cross-validation for estimating the model performance. The reliability of the constructed model was validated using an unseen test set. The model was then trained with hyperparameter optimization.
Results:
During the feature selection process, 27 features were identified as meaningful factors for frailty. The model was trained based on the selected features, and the weighted average F1-score reached 95.30% with the random forest algorithm.
Conclusions
The results of the study demonstrated the possibility of adopting machine learning to strengthen existing frailty criteria. As the method analyzes questionnaire responses in a short time, it can support higher volumes of data on participants’ health conditions and alert them regarding potential risks in advance.

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