• Investigative Magnetic Resonance Imaging
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• v.25 no.2
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• pp.93-100
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• 2021

Purpose: (1) To evaluate the trabecular pattern at the femoral attachment of the posterior cruciate ligament (PCL) in patients with a PCL injury; (2) to analyze bone microarchitecture by applying gray level co-occurrence matrix (GLCM)-based texture analysis; and (3) to determine if there is a significant relationship between bone microarchitecture and posterior instability. Materials and Methods: The study included 96 patients with PCL tears. Trabecular patterns were evaluated on T2-weighted MRI qualitatively, and were evaluated by GLCM texture analysis quantitatively. The grades of posterior drawer test (PDT) and the degrees of posterior displacement on stress radiographs were recorded. The 96 patients were classified into two groups: acute and chronic injury. And 27 patients with no PCL injury were enrolled for control. Pearson's correlation coefficient and one-way ANOVA with Bonferroni test were conducted for statistical analyses. This protocol was approved by the Institutional Review Board. Results: A thick and anisotropic trabecular bone pattern was apparent in normal or acute injury (n = 57/61;93.4%), but was not prominent in chronic injury and posterior instability (n = 31/35;88.6%). Grades of PDT and degrees of posterior displacement on stress radiograph were not correlated with texture parameters. However, the texture analysis parameters of chronic injury were significantly different from those of acute injury and control groups (P < 0.05). Conclusion: The trabecular pattern and texture analysis parameters are useful in predicting posterior instability in patients with PCL injury. Evaluation of the bone microarchitecture resulting from altered biomechanics could advance the understanding of PCL function and improve the detection of PCL injury.

• Anxiety and mood
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• v.18 no.2
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• pp.39-47
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• 2022

Objective : This study investigated brain functional connectivity in male firefighters who showed subclinical post-traumatic stress disorder (PTSD) symptoms. Methods : We compared the data of 17 firefighters who were not diagnosed with PTSD and 18 healthy controls who had no trauma exposure. The following instruments were applied to assess psychiatric symptoms: Korean version of the Post-traumatic stress disorder Checklist for DSM-5 (PCL-5-K), Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory (BAI). For all subjects, functional magnetic resonance imaging was performed, and functional connectivity was compared between the two groups (family-wise error-corrected p<0.05). Additionally, correlations between psychiatric symptoms and functional connectivity were explored. Results : The following connectivity was higher than that of healthy controls: 1) the central opercular cortex-superior temporal gyrus, 2) planum polare-parahippocampal gyrus, 3) angular gyrus-amygdala, and 4) temporal fusiform cortex-parahippocampal gyrus. The functional connectivity of 1) the lateral occipital cortex-inferior temporal gyrus, 2) superior parietal lobule-caudate, and 3) middle temporal gyrus-thalamus were lower in firefighters. In firefighters, the connectivity of the planum polare-parahippocampal gyrus showed a negative correlation with the severity of arousal symptoms (rho=-0.586, p=0.013). The connectivity of the middle temporal gyrus-thalamus showed a positive correlation with the severity of intrusion (rho=0.552, p=0.022) and arousal symptoms (rho=0.619, p=0.008). The connectivity of the temporal fusiform cortex-parahippocampal gyrus was negatively correlated with intrusion (rho=-0.491, p=0.045) and arousal (rho=-0.579, p=0.015). Conclusion : Our results indicate that the brain functional connectivity is associated with occupational trauma exposure in firefighters without PTSD. Therefore, this study provides evidence that close monitoring and early intervention are important for firefighters with traumatic experience even at a subthreshold level.

• Agricultural and Biosystems Engineering
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• v.1 no.2
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• pp.88-94
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• 2000

Nitrogen (N) management is critical for corn production. On the other hand, N leaching into the groundwater creates serious environmental problems. There is a demand for sensors that can assess the plant N deficiency throughout the growing season to allow producers to reach their production goals, while maintaining environmental quality. This paper reports on the performance of a vision-based reflectance sensor for real-time assessment of N stress level of corn crops. Data were collected representing the changes in crop reflectance in various spectral ranges over several stages of development in the growing season. The performance of this non-contact sensor was validated under various field conditions with reference measurement from a Minolta SPAD meter and stepped nitrogen treatments.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.155-160
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• 1993

The identification of viable myocardium in patients with coronary artery disease and left ventricular dysfunction is an issue of increasing clinical relavance in the current era of myocardial revascularization. There are at least two forms of reversible myocardial dysfunction. Early reperfusion does not always lead to immediate functional improvement; rather, the return of contractility in tissue salvaged by reperfusion is delayed for hours, days or even weeks, a phenomenon that has been termed "stunned myocardium". Some patients with coronary artery disease show myocardial dysfunction at rest which are associated with reduced perfusion, and which disappear after revascularization; this phenomenon has been termed "hibernating myocardium". Recently, cardiac imaging techniques that evaluate myocardial viability on the basis of perfusion-contraction mismatch and inotropic reserve have gained substantial popularity and clinical success. This review focus on the application of $^{201}TI$ and $^{99m}Tc-MIBI$ to address myocardial viability in patients with hibernating and stunned myocardium. It is clear that 4-hour redistribution images of $^{201}TI$ underestimate ischemia and overestimate scar. Delayed imaging and reinjection imaging have been developed for the assessment of viability. Among many protocols suggested, stress-redistribution-reinjection imaging gained most popularity. Although $^{99m}Tc-MIBI$ could identify myocardial viability, $^{201}TI$ reinjection technique was regarded as superior to it. In conclusion, $^{201}TI$ stress, 4-hr rest redistribution, and reinjection imaging technique may be the most preferable method for evaluation of myocardial viability.

• Journal of the Korean Society of Radiology
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• v.5 no.4
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• pp.201-205
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• 2011

Subacute Ankle Sprain patients, 3 tests have been acknowledge for diagnostic precision and thus most commonly used to test their soft tissues, muscles, and ligaments: ankle stress-valgus test, anterior-draw test, and MRI scan. Although not much different from the rest two in its diagnostic value, MRI costs patients some money and time. Also, we have reached the conclusion through an experiment with a group of patients in a certain hospital that the rest two methods is as efficient and useful as MRI in diagnosing ankle joint patients.

• Journal of Korean Biological Nursing Science
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• v.23 no.3
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• pp.159-169
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• 2021

Purpose: The purpose of this study was to analyze research trends and find whether Post-Traumatic Stress Disorder (PTSD) of refugees could affect structural or functional changes of brains of those under MRI, focusing on volumes, functional connectivities, and metabolites. Methods: A literature search was done using PubMed, Embase, RISS, and KMBase to identify studies that matched our research purpose. A total of eight studies were identified using Prisma flow diagram by two reviewers independently. Results: Eight studies were identified. Three studies were on North Korean defectors as subjects. The number of studies that observed structural changes, functional changes, and metabolite changes in brains was 2, 5, and 2, respectively. Although each study observed various parts of the brain, anterior cingulate cortex (ACC) was observed commonly in three studies. The PTSD group showed reduction of ACC volume and N-acetyl-aspartate (NAA) metabolite in ACC compared to the non- PTSD group. When exposed to negative stimuli, the PTSD group showed higher neural activity than the non-PTSD group, but not vice versa. Conclusion: ACC showed significant difference in volume, neural activity, and NAA metabolite between the PTSD and the non-PTSD group, resulting in significant differences in structural changes, functional changes, metabolite changes, respectively. This study showed the need for conducting more research using various biomarkers to clarify the relationship between PTSD of refugees and their brain changes.

• Journal of Cardiovascular Imaging
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• v.30 no.3
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• pp.169-180
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• 2022

BACKGROUND: We analyzed whether C-11 acetate positron emission tomography (PET) can be used for the evaluation of non-infarct-related artery (NIRA) in patients with ST-elevation myocardial infarction (STEMI) and multivessel disease. METHODS: We prospectively enrolled 31 patients with STEMI and at least one NIRA stenosis (diameter stenosis [DS] ≥ 50%). C-11 acetate PET was performed after successful revascularization for the infarct-related artery (IRA). Myocardial blood flow (MBF) and oxidative metabolism (k_mono) were measured and compared between NIRA vs. IRA, stenotic (DS ≥ 50%) vs. non-stenotic (DS < 50%) NIRAs, and NIRAs with significant stenosis (DS ≥ 70% or fractional flow reserve [FFR] ≤ 0.80) vs. those without (neither DS ≥ 70% nor FFR ≤ 0.80). The correlations between PET and angiographic parameters were also analyzed. RESULTS: MBF and k_mono were significantly higher in NIRAs than those in IRAs. Stenotic NIRAs showed significantly reduced stress MBF, myocardial flow reserve (MFR), relative flow reserve (RFR) (0.72 ± 0.12 vs. 0.82 ± 0.14; p = 0.001), and stress k_mono, as compared to those in non-stenotic NIRAs. NIRAs with significant stenosis had significantly lower stress MBF, MFR, and RFR (0.70 ± 0.10 vs. 0.80 ± 0.14; p = 0.001). RFR showed the best, but modest linear correlation with DS of NIRA stenosis (r = -0.429, p = 0.001). RFR > 0.81 could effectively exclude the presence of significant NIRA stenosis. CONCLUSIONS: C-11 acetate PET could be a feasible alternative noninvasive modality in patients with STEMI and multivessel disease, by excluding the presence of significant NIRA stenosis.

• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.484-493
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• 2012

Since the 1980s, there have been many research activities devoted to quantitatively characterizing and imaging human tissues based on sound speed, attenuation coefficient, density, nonlinear B/A parameter, etc., but those efforts have not yet reached the stage of commercialization. However, a new imaging technology termed elastography, which was proposed in the early 1980s, has recently been implemented in commercial clinical ultrasound scanners, and is now being used to diagnose prostates, breasts, thyroids, livers, blood vessels, etc., more quantitatively as a complementary adjunct modality to the conventional B-mode imaging. The purpose of this article is to introduce and review various elastographic algorithms for use in quasistatic or static compression type elasticity imaging modes. Most of the algorithms are based on the crosscorrelation or autocorrelation function methods, and the fundamental difference is that the time shift is estimated by changing the lag variable in the former, while it is directly obtained from the phase shift at a fixed lag in the latter.

• Journal of Animal Science and Technology
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• v.66 no.1
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• pp.31-56
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• 2024

Pig farming, a vital industry, necessitates proactive measures for early disease detection and crush symptom monitoring to ensure optimum pig health and safety. This review explores advanced thermal sensing technologies and computer vision-based thermal imaging techniques employed for pig disease and piglet crush symptom monitoring on pig farms. Infrared thermography (IRT) is a non-invasive and efficient technology for measuring pig body temperature, providing advantages such as non-destructive, long-distance, and high-sensitivity measurements. Unlike traditional methods, IRT offers a quick and labor-saving approach to acquiring physiological data impacted by environmental temperature, crucial for understanding pig body physiology and metabolism. IRT aids in early disease detection, respiratory health monitoring, and evaluating vaccination effectiveness. Challenges include body surface emissivity variations affecting measurement accuracy. Thermal imaging and deep learning algorithms are used for pig behavior recognition, with the dorsal plane effective for stress detection. Remote health monitoring through thermal imaging, deep learning, and wearable devices facilitates non-invasive assessment of pig health, minimizing medication use. Integration of advanced sensors, thermal imaging, and deep learning shows potential for disease detection and improvement in pig farming, but challenges and ethical considerations must be addressed for successful implementation. This review summarizes the state-of-the-art technologies used in the pig farming industry, including computer vision algorithms such as object detection, image segmentation, and deep learning techniques. It also discusses the benefits and limitations of IRT technology, providing an overview of the current research field. This study provides valuable insights for researchers and farmers regarding IRT application in pig production, highlighting notable approaches and the latest research findings in this field.

• YAKHAK HOEJI
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• v.59 no.4
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• pp.158-163
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• 2015

Cardiac myocytes are subjected to fluid shear stress during each contraction and relaxation. Under pathological conditions, such as valve disease, heart failure or hypertension, shear stress in cardiac chamber increases due to high blood volume and pressure. The shear stress induces proarrhythmic longitudinal global $Ca^{2+}$ waves in atrial myocytes. In the present study, we further explored underlying cellular mechanism for the shear stress-induced longitudinal global $Ca^{2+}$ wave in isolated rat atrial myocytes. A shear stress of ${\sim}16dyn/cm^2$ was applied onto entire single myocyte using pressurized fluid puffing. Confocal $Ca^{2+}$ imaging was performed to measure local and global $Ca^{2+}$ signals. Shear stress elicited longitudinally propagating global $Ca^{2+}$ wave (${\sim}80{\mu}m/s$). The occurrence of shear stress-induced atrial $Ca^{2+}$ wave was eliminated by the inhibition of ryanodine receptors (RyRs) or inositol 1,4,5-trisphosphate receptors ($IP_3Rs$). In addition, pretreatment of phospholipase C (PLC) inhibitor U73122, but not its inactive analogue U73343, abolished the generation of longitudinal $Ca^{2+}$ wave under shear stress. Our data suggest that shear-induced longitudinal $Ca^{2+}$ wave may be induced by $Ca^{2+}$-induced $Ca^{2+}$ release through the RyRs which is triggered by $PLC-IP_3R$ signaling in atrial myocytes.