• Korean Journal of Radiology
• /
• v.23 no.12
• /
• pp.1269-1280
• /
• 2022

Objective: This study aimed to evaluate the usefulness of quantitative indices obtained from deep learning analysis of gadoxetic acid-enhanced hepatobiliary phase (HBP) MRI and their longitudinal changes in predicting decompensation and death in patients with advanced chronic liver disease (ACLD). Materials and Methods: We included patients who underwent baseline and 1-year follow-up MRI from a prospective cohort that underwent gadoxetic acid-enhanced MRI for hepatocellular carcinoma surveillance between November 2011 and August 2012 at a tertiary medical center. Baseline liver condition was categorized as non-ACLD, compensated ACLD, and decompensated ACLD. The liver-to-spleen signal intensity ratio (LS-SIR) and liver-to-spleen volume ratio (LS-VR) were automatically measured on the HBP images using a deep learning algorithm, and their percentage changes at the 1-year follow-up (ΔLS-SIR and ΔLS-VR) were calculated. The associations of the MRI indices with hepatic decompensation and a composite endpoint of liver-related death or transplantation were evaluated using a competing risk analysis with multivariable Fine and Gray regression models, including baseline parameters alone and both baseline and follow-up parameters. Results: Our study included 280 patients (153 male; mean age ± standard deviation, 57 ± 7.95 years) with non-ACLD, compensated ACLD, and decompensated ACLD in 32, 186, and 62 patients, respectively. Patients were followed for 11-117 months (median, 104 months). In patients with compensated ACLD, baseline LS-SIR (sub-distribution hazard ratio [sHR], 0.81; p = 0.034) and LS-VR (sHR, 0.71; p = 0.01) were independently associated with hepatic decompensation. The ΔLS-VR (sHR, 0.54; p = 0.002) was predictive of hepatic decompensation after adjusting for baseline variables. ΔLS-VR was an independent predictor of liver-related death or transplantation in patients with compensated ACLD (sHR, 0.46; p = 0.026) and decompensated ACLD (sHR, 0.61; p = 0.023). Conclusion: MRI indices automatically derived from the deep learning analysis of gadoxetic acid-enhanced HBP MRI can be used as prognostic markers in patients with ACLD.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.46 no.1
• /
• pp.46-55
• /
• 2017

In this study, extracts of gamma-irradiated Aralia continentalis for health and beauty food resources were examined on antioxidant activities and increasing extraction yield. In photostimulated luminescence analysis, non-irradiated (0 kGy) sample showed an intermediate result of 891.00 photon counts (PCs), whereas irradiated (5 and 10 kGy) samples showed positive results of 79,956.67 and 282,498.67 PCs, respectively. The thermoluminescence ratio of non-irradiated samples was 0.018, whereas the values of irradiated samples (5 and 10 kGy) were 0.395 and 0.464, respectively. Electron spin resonance (ESR) analysis as a physical technique for irradiation identification of Aralia continentalis showed a pair of peaks on a space of 6.0 mT in the symmetric ESR spectrums. For phenolics of gamma-irradiated Aralia continentalis, water extracts had the highest amounts of 7.61 mg/g at non-irradiated condition (0 kGy) while 50% ethanol extracts had the highest amounts of 6.86 mg/g at 10 kGy irradiation. 2,2-Diphenyl-1-picrylhydrazyl scavenging activity of water and 50% ethanol extracts from non-irradiated and irradiated Aralia continentalis were very high (94.99~100.00%). 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical cation inhibitory activity was over 95.00% at $200{\mu}g/mL$ phenolics. Antioxidant protection factor (PF) showed a very high level of activity (1.38~2.51 PF). Thiobarbituric acid reactive substance inhibitory activity was high (70% and 95%, respectively). Thus, treatment of gamma irradiation can be used as a method of storage for long-term preservation of Oriental medicine.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.1
• /
• pp.94-131
• /
• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.

• Journal of the Korean Orthopaedic Association
• /
• v.53 no.6
• /
• pp.540-546
• /
• 2018

Purpose: The purpose of this study was to suggest a multimodal diagnostic approach to determine the cause of the disease in patients diagnosed with synovitis of the wrist and who underwent synovectomy. Materials and Methods: Twenty-nine patients, who underwent contrast magnetic resonance imaging (MRI) preoperatively and synovectomy from January 2000 to December 2013, were reviewed retrospectively. Among them, 17 patients underwent a $Tc^{99m}$ white blood cell (WBC) scan preoperatively. In patients who met the diagnostic criteria of rheumatoid arthritis (RA), the diagnosis was confirmed as RA if the MRI finding or histology was compatible with RA. If the MRI finding and histology were disparate, the final diagnosis was made based on the histologic finding. Results: Of the nine patients who met the diagnostic criteria of RA, seven patients were finally diagnosed as RA and two patients as tuberculous arthritis. Of the 20 patients who did not meet the diagnostic criteria of RA, the MRI findings and histology were consistent with the same disease in 12 patients. In the remaining eight patients, five were diagnosed with nonspecific chronic synovitis, one with RA, and two with tuberculous arthritis based on the clinical findings, MRI, and histology findings. Conclusion: MRI and a WBC scan are very useful imaging modalities for diagnosing the causative condition of the wrist synovitis. A histology evaluation after synovectomy can also be useful in cases with a difficult diagnosis or are refractory to medications.

• Journal of the Korean Society of Radiology
• /
• v.83 no.1
• /
• pp.102-111
• /
• 2022

Purpose To evaluate the correlation between Lee's grades and surgical intervention for central lumbar spinal stenosis (CLSS) and to assess whether this grading system can be used as a decision-making tool for the surgical treatment of this condition. Materials and Methods This retrospective study included 290 patients (M:F = 156:134; mean age, 46 ± 16 years). Radiologists assessed the presence and grade of CLSS at the stenosis point according to Lee's grading system, in which CLSS is classified into four grades according to the shape of the cauda equina. Correlation coefficients (r_s) between Lee's grades and the operation were calculated with Spearman rank correlation. Results Among the operated patients, grade 2 was the most commonly assigned grade (50%-58%), grade 3 was less common (35%), and grade 0 was the least common (2%-3%). Among the non-operated patients, grade 1 was the most common (63%-65%), grade 0 was less common (15%-16%), and grade 3 was the least common (8%). The distribution of grades differed between the operated and non-operated groups (p < 0.001). Less than 25% of patients who underwent surgery were assigned grades 0 and 1, and more than 88% were assigned grades 2 and 3. A moderate correlation was found between the grade and surgical intervention (r_s = 0.632 and r_s = 0.583). Conclusion Lee's grade was moderately correlated with surgical intervention. Lee's grading system can be a decision-making tool for the surgical treatment of CLSS.