1.Dehazing Algorithm for Enhancing Fundus Photographs Using Dark Channel and Bright Channel Prior
Sehie PARK ; Hyungjin CHUNG ; Jong Chul YE ; Kayoung YI
Journal of the Korean Ophthalmological Society 2024;65(1):44-52
Purpose:
We present a dehazing algorithm using dark channel prior (DCP) and bright channel prior (BCP) to enhance the quality of retinal images obtained through conventional fundus photography.
Methods:
A retrospective analysis was conducted on retinal images from patients who visited Gangnam Sacred Heart Hospital between January 2000 and September 2022. These images were captured using a digital fundus camera (KOWA Nonmyd 8S Fundus Camera, KOWA Company, Nagoya, Japan) without pupil dilation. We used two mathematical algorithms: DCP only and DCP and BCP combined. The original, DCP-processed, and DCP & BCP-processed images were compared. Fisher's exact test was used to identify significant quality improvements.
Results:
The DCP and the newly proposed DCP plus BCP algorithm effectively eliminated haze and enhanced the contrast of cataract images. Notably, DCP demonstrated limited improvements in fundus photographs from patients with small pupils, whereas the proposed DCP plus BCP method effectively revealed previously obscured retinal details and vessels. However, these methods exhibited limited performance in severe cataracts compared to the clear images obtained after surgery. The quality enhancement with the proposed method was significant in photographs of patients with cataracts (p = 0.032) and small pupils (p < 0.01).
Conclusions
Our algorithm produced clearer images of blood vessels and optic disc structures, while significantly reducing artifacts in fundus images from patients with small pupils or cataracts. The proposed algorithm can provide visually enhanced images, potentially aiding physicians in the diagnosis of retinal diseases in patients with cataracts.
2.The Effect of High-Frequency Repetitive Transcranial Magnetic Stimulation on Occupational Stress among Health Care Workers: A Pilot Study.
Young In KIM ; Sun Mi KIM ; Hyungjin KIM ; Doug Hyun HAN
Psychiatry Investigation 2016;13(6):622-629
OBJECTIVE: Repetitive transcranial magnetic stimulation (rTMS) was approved by the Food and Drug Administration to alleviate symptoms of treatment-resistant depression. This study aimed to evaluate the effectiveness of rTMS treatment on alleviating occupational stress by evaluating clinical symptoms and quantitative electroencephalography (QEEG). METHODS: Twenty-four health care workers were randomized to receive 12 sessions of active or sham rTMS delivered to the left dorsolateral prefrontal cortex (DLPFC). Each session consisted of 32 trains of 10 Hz repetitive TMS delivered in 5-second trains at 110% of the estimated prefrontal cortex threshold. Before and after the intervention, the Korean version of the occupational stress inventory (K-OSI), Beck's depression inventory (BDI), and Beck's anxiety inventory (BAI) were administered and EEG was performed using a 21-channel digital EEG system. RESULTS: After TMS, the average scores for the affective responses to stressors on the personal strain questionnaire (PSQ) subscale of K-OSI and BDI decreased significantly for the active-TMS group compared to the sham-TMS group. Also, the active-TMS group showed a significantly greater decrease in relative alpha in the F3 electrode and a significantly greater increase in the F4 electrode. CONCLUSION: High-frequency rTMS on the left DLPFC had stress-relieving and mood-elevating effects in health care workers, likely by stimulating the left frontal lobe.
Anxiety
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Delivery of Health Care*
;
Depression
;
Electrodes
;
Electroencephalography
;
Frontal Lobe
;
Humans
;
Pilot Projects*
;
Prefrontal Cortex
;
Transcranial Magnetic Stimulation*
;
United States Food and Drug Administration
3.Genetic, Clinicopathological, and Radiological Features of Intrahepatic Cholangiocarcinoma with Ductal Plate Malformation Pattern
Taek CHUNG ; Hyungjin RHEE ; Hyo Sup SHIM ; Jeong Eun YOO ; Gi Hong CHOI ; Haeryoung KIM ; Young Nyun PARK
Gut and Liver 2022;16(4):613-624
Background/Aims:
Intrahepatic cholangiocarcinoma (iCCA) with a ductal plate malformation (DPM) pattern is a recently recognized rare variant. The genomic profile of iCCA with DPM pattern needs to be elucidated.
Methods:
Cases of iCCA with DPM pattern were retrospectively reviewed based on the medical records, pathology slides, and magnetic resonance imaging (MRI) reports collected between 2010 to 2019 at a single center. Massive parallel sequencing was performed for >500 cancerrelated genes.
Results:
From a total of 175 iCCAs, five (2.9%) cases of iCCA with DPM pattern were identified. All cases were of the small duct type, and background liver revealed chronic B viral or alcoholic hepatitis. Three iCCAs with DPM pattern harbored MRI features favoring the diagnosis of hepatocellular carcinoma, whereas nonspecific imaging features were observed in two cases. All patients were alive without recurrence during an average follow-up period of 57 months. Sequencing data revealed 64 mutated genes in the five cases, among which FGFR2 and PTPRT were most frequently mutated (three cases each) including an FGFR2-TNC fusion in one case. Mutations in ARID1A and CDKN2A were found in two cases, and mutations in TP53, BAP1, ATM, NF1, and STK11 were observed in one case each. No IDH1, KRAS, or PBRM1 mutations were found.
Conclusions
iCCAs with DPM pattern have different clinico-radio-pathologic and genetic characteristics compared to conventional iCCAs. Moreover, FGFR2 and FGFR2 variants were identified. Altogether, these findings further suggest that iCCA with DPM pattern represents a specific subtype of small duct type iCCA.
4.Increased Expression of the Matrix-Modifying Enzyme Lysyl Oxidase-Like 2 in Aggressive Hepatocellular Carcinoma with Poor Prognosis.
Jiwoon CHOI ; Taek CHUNG ; Hyungjin RHEE ; Young Joo KIM ; Youngsic JEON ; Jeong Eun YOO ; Songmi NOH ; Dai Hoon HAN ; Young Nyun PARK
Gut and Liver 2019;13(1):83-92
BACKGROUND/AIMS: Lysyl oxidase-like 2 (LOXL2), a collagen-modifying enzyme, has been implicated in cancer invasiveness and metastasis. METHODS: We evaluated the expression of LOXL2 protein, in addition to carbonic anhydrase IX (CAIX), keratin 19, epithelial cell adhesion molecule, and interleukin 6, in 105 resected hepatocellular carcinomas (HCCs) by immunohistochemistry. RESULTS: LOXL2 positivity was found in 14.3% (15/105) of HCCs, and it was significantly associated with high serum α-fetoprotein levels, poor differentiation, fibrous stroma, portal vein invasion, and advanced TNM stage (p < 0.05 for all). Additionally, LOXL2 positivity was significantly associated with CAIX (p=0.005) and stromal interleukin 6 expression (p=0.001). Survival analysis of 99 HCC patients revealed LOXL2 positivity to be a poor prognostic factor; its prognostic impact appeared in progressed HCCs. Furthermore, LOXL2 positivity was shown to be an independent predictor of overall survival and disease-specific survival (p < 0.05 for all). Interestingly, co-expression of LOXL2 and CAIX was also an independent predictor for overall survival, disease-specific survival, disease-free survival, and extrahepatic recurrence-free survival (p < 0.05 for all). CONCLUSIONS: LOXL2 expression represents a subgroup of HCCs with more aggressive behavior and is suggested to be a poor prognostic marker in HCC patients.
Carbonic Anhydrases
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Carcinoma, Hepatocellular*
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Disease-Free Survival
;
Epithelial Cells
;
Extracellular Matrix
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Humans
;
Immunohistochemistry
;
Interleukin-6
;
Keratin-19
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Neoplasm Metastasis
;
Portal Vein
;
Prognosis*
5.Romosozumab in Postmenopausal Korean Women with Osteoporosis: A Randomized, Double-Blind, Placebo-Controlled Efficacy and Safety Study
Ki-Hyun BAEK ; Yoon-Sok CHUNG ; Jung-Min KOH ; In Joo KIM ; Kyoung Min KIM ; Yong-Ki MIN ; Ki Deok PARK ; Rajani DINAVAHI ; Judy MADDOX ; Wenjing YANG ; Sooa KIM ; Sang Jin LEE ; Hyungjin CHO ; Sung-Kil LIM
Endocrinology and Metabolism 2021;36(1):60-69
Background:
This phase 3 study evaluated the efficacy and safety of 6-month treatment with romosozumab in Korean postmenopausal women with osteoporosis.
Methods:
Sixty-seven postmenopausal women with osteoporosis (bone mineral density [BMD] T-scores ≤–2.5 at the lumbar spine, total hip, or femoral neck) were randomized (1:1) to receive monthly subcutaneous injections of romosozumab (210 mg; n=34) or placebo (n=33) for 6 months.
Results:
At month 6, the difference in the least square (LS) mean percent change from baseline in lumbar spine BMD (primary efficacy endpoint) between the romosozumab (9.5%) and placebo (–0.1%) groups was significant (9.6%; 95% confidence interval, 7.6 to 11.5; P<0.001). The difference in the LS mean percent change from baseline was also significant for total hip and femoral neck BMD (secondary efficacy endpoints). After treatment with romosozumab, the percent change from baseline in procollagen type 1 N-terminal propeptide transiently increased at months 1 and 3, while that in C-terminal telopeptide of type 1 collagen showed a sustained decrease. No events of cancer, hypocalcemia, injection site reaction, positively adjudicated atypical femoral fracture or osteonecrosis of the jaw, or positively adjudicated serious cardiovascular adverse events were observed. At month 9, 17.6% and 2.9% of patients in the romosozumab group developed binding and neutralizing antibodies, respectively.
Conclusion
Treatment with romosozumab for 6 months was well tolerated and significantly increased lumbar spine, total hip, and femoral neck BMD compared with placebo in Korean postmenopausal women with osteoporosis (ClinicalTrials.gov identifier NCT02791516).