• Journal of radiological science and technology
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• v.34 no.1
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• pp.17-25
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• 2011

In this study, we examined the impact caused by chronic exposure to Mn by investigating the degree of brain activation based on the data of recognition activities using fMRI (functional magnetic resonance imaging). A questionnaire survey, blood tests, and fMRI tests were carried out with respect to two groups. Group 1 was an exposure group consisting of 15 male workers who are 34 years old or older, and who worked for longer than 10 years in a shipbuilding factory as a welder. Group 2 was a control group consisting of 15 workers in manufacturing industries with the same gender and age. The results showed that blood Mn concentration of Group 1($1.3\;{\mu}g/dl$) was significantly higher than that of Group 2($0.8\;{\mu}g/dl$)(p < 0.001), and Pallidal Index (PI) of Group 1 was also significantly higher than that of Group 2 (p < 0.001). PI value of the group whose blood Mn concentration was $0.93\;{\mu}g/dl$ or higher was significantly higher than that of the group whose blood Mn concentration was less than $0.93 \;{\mu}g/dl$ (p < 0.001). As for brain activity area within the control group, the right and the left areas of occipital cortex showed significant activity and the left area of middle temporal cortex, the right area of superior inferior frontal cortex and inferior parietal cortex showed significant activity. Unlike the control group, the exposure group showed significant activity on the right area of superior inferior temporal cortex, the left of insula area. In the comparison of brain activity areas between the two groups, the exposure group showed significantly higher activation than the control group in such areas as the right inferior temporal cortex, the left area of superior parietal cortex and occipital cortex, and cerebellum including middle temporal cortex. However, in nowhere the control group showed more activated area than the exposure group. As the final outcome, chronic exposure to Mn increased brain activity during implementation of arithmetic task. In an identical task, activation increased in superior inferior temporal cortex, and insula area. And it was discovered that brain activity increase in temporal area and occipital area was more pronounced in the exposure group than in the control group. This result suggests that chronic exposure to Mn in the work environment affects brain activation neuro-network.

• Clinical and Experimental Pediatrics
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• v.52 no.11
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• pp.1221-1227
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• 2009

Purpose:To identify the risk factors for poor neurodevelopmental outcomes in high-risk neonates. Methods:We studied 94 infants admitted to the neonatal intensive care unit at the Sanggye Paik Hospital between January 2002 and November 2005 and evaluated the follow-up data. The following events were considered as risk factors: ${\leq}32$ weeks of gestation, very low birth weight, Apgar scores of less than 5, neonatal resuscitation, neonatal seizure, congenital infection, and abnormalities in cranial ultrasound or magnetic resonance imaging (MRI). The infants who had any one of these risk factors were included. They were evaluated at their mean corrected age of 13.84${\pm}$8.03 months. Mental and Psychomotor Developmental Indices (MDI, PDI) were determined by a clinical psychologist using the Bayley Scales of Infant Development II. Results:The mean MDI and PDI of all the patients were 96.28${\pm}$26.70 and 94.00${\pm}$22.80, respectively. Abnormalities on cranial ultrasound or MRI were significant predictors of both low MDI (P<0.05) and low PDI (P<0.001). These abnormalities showed a stronger association with low PDI than with low MDI. The infants with periventricular leukomalacia had the lowest MDI and PDI ($70.10{\pm}28.68$ and $69.70{\pm}24.91$, respectively). Apgar score at 1 minute and very low birth weight were also significant predictors for low PDI (P<0.05, P<0.05, respectively). Conclusion:Image findings with cranial ultrasound or MRI were the strongest predictors of neurodevelopmental outcome. Periventricular leukomalacia was the best predictive factor for mental and psychomotor development.

• Journal of radiological science and technology
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• v.26 no.3
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• pp.25-31
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• 2003

This study was performed to evaluate the usefulness of Deconvolution perfusion CT in patients with acute cerebral infarction. Nine patients with acute cerebral infarction underwent conventional CT and cerebral perfusion CT within 23 hours of the onset of symptoms. The perfusion CT scan for each patient was obtained at the levels of basal ganglia and 1cm caudal to the basal ganglia. By special imaging software, perfusion images including cerebral blood volume(CBV), cerebral blood flow(CBF), and mean transit time(MTT) maps were created. The created lesions were evaluated on each perfusion maps by 3 radiolocical technician. MTT delay time was measured in the perfusion defect lesion and symmetric contralateral normal cerebral hemisphere. Lesion sire were measured on each perfusion map and compared with the value obtained by diffusion weighted MR imaging(DWMRI). All perfusion CT maps showed the perfusion defect lesion in all patients. There were remarkable CT delay in perfusion defect lesion. In comparison of lesion size between each perfusion map and DWMRI, the lesion on CBF map was the most closely correlated with the lesion on DWMRI(7/9). The size of perfusion defect lesion on MTT map was larger than that of lesion on DWMRI, suggesting that m map can evaluate the ischemic penumbra. Deconvolution Perfusion CT maps make it possible to evaluate not only ischemic core and ischemic penumbra but also hemodynamic status in perfusion defect area. These results demonstrate that perfusion CT can be useful to the diagnosis and treatment in the patients with acute cerebral ischemic infarction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.373-382
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• 2000

Temporomandibular disorders arised from joint itself was caused by inflammation or mechanical irritation of the retrodiskal tissues. Histologic changes of the retrodiskal tissues of temporomandibular joint(TMJ) internal derangement, such as inflammatory cell infiltration, hyalinization, myxoid change, fatty change, arterial obliteration, and so on, were reported, but relationships between magnetic resonance imaging(MRI) findings and histologic findings of the retrodiskal tissue were few reported. The purpose of this study was to find histologic changes of the retrodiskal tissues for status of joint and joint effusion in MRI of the temporomandibular joint which had surgical treatment. Materials were surgically treated 52 temporomandibular joints with internal derangement or osteoarthritis in TMJ clinic, Yongdong Severance Hospital. All joints were confirmed by magnetic resonance T1- and T2-weighted imagings bofere surgery. Status of joint was categorized by normal position, disc displacement with reduction, disc displacement without reduction, disc displacement without reduction associated with osteoarthrosis using preoperative MR T1-weighted images. Magnetic resonance evidence of joint effusion was observed in T2-weighted images and classified by its amount; degree 0(not observed), degree 1(small amount), degree 2(moderate amount), degree 3(large amount). Histologic features were observed whether the retrodiskal tissue has inflammatory cell infiltration, myxoid change, hyalinization, chondroid metaplasia and arterial obliteration. The distribution of elastic fibers were also observed. The results were as follows; 1. Inflammatory cell infiltration was not observed in any retrodiskal tissues. 2. MRI findings such as status of joint and evidence of joint effusion did not have significant relationship with myxoid change, hyalinization, chondroid metaplasia, arterial obliteration of the retrodiskal tissues. 3. Hyalinization and chondroid metaplasia were found in 8 joints(15.4%) and 5 joints(9.6%). All of them were found in disc displacement without reduction and disc displacement without reduction associated with osteoarthrosis. 4. Arterial obliteration was observed more frequently in disc displacement without reduction(55.6%) than disc displacement without reduction associated with osteoarthrosis(28.6%). Further studies with proper controls and more materials will be necessary.

• The Journal of the Korean bone and joint tumor society
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• v.13 no.2
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• pp.195-200
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• 2007

Dedifferentiated parosteal osteosarcoma is an uncommon variant of osteosarcoma. Dedifferentiation is known to be associated with a greater metastatic potential and a more rapid lethal clinical course. Thus recognition of dedifferentiation is important to establish the treatment strategy. But there may be few significant clinical clues to distinguish between dedifferentiated parosteal osteosarcoma and conventional one. A 29-year-old woman presented with 2-year history of discomfort and swelling in her proximal thigh. Examination showed a large, hard, non-mobile mass. Radiographs revealed a large ossified mass attached to the proximal femur. Diagnosis of parosteal osteosarcoma was established by MRI and needle biopsy. But she had a history of abrupt severe thigh pain and increased swelling before surgery. Follow up MRI showed enlargement of mass with invasion to muscle around tumor. The patient underwent an en-bloc resection of tumor and reconstruction. Histological examination showed parosteal sarcoma with dedifferentiation. The patient expired due to local recurrence of tumor and distant lung metastasis 2 months after the surgery. In case with rapid growth of a lesion or unusual severe pain, one must have a high index of suspicion with regard to dedifferentiation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.38 no.1
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• pp.1-9
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• 2024

Cognitive reserve (CR) is a concept that can explain the discrepancies between the pathologic burden of the disease and clinical manifestations. It refers to the individual susceptibility to age-related brain changes and pathologies related to Alzheimer's disease, thus recognized as a factor affecting the trajectories of the disease. The purpose of this study was to explore the current states of clinical studies on neural substrates of CR in Alzheimer's disease using functional magnetic resonance imaging. We searched for clinical studies on CR using fMRI in the Pubmed, Cochrane library, RISS, KISS and ScienceON on August 14, 2023. Once the online search was finished, studies were selected manually by the inclusion criteria. Finally, we analyzed the characteristics of selected articles and reviewed the neural substrates of CR. Total thirty-four studies were included in this study. As surrogate markers of CR, not only education and occupational complexity, but also composite score and questionnaire-based method, which cover various areas of life, were mainly used. The most utilized methods in resting-state fMRI were independent component analysis, seed-based analysis, and graph theory analysis. Through the analysis, we demonstrated that neuroimaging techniques could capture the neural substrates associated with cognitive reserve. Moreover, functional connectivity of brain regions centered on prefrontal and parietal cortex and network areas such as default mode network showed a significant correlation with CR, which indicated a significant association with cognitive performance. CR may induce differential effects according to the disease status. We hope that this perspective on cognitive reserve would be helpful when conducting clinical researches on the mechanisms of traditional Korean medicine for Alzheimer's disease in the future.

• Journal of the Korean Society of Radiology
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• v.15 no.4
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• pp.555-564
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• 2021

Thalamus is known to play an important role in the regulation of nerve function. Thalamus, located in the center of the brain, is involved in sleep, arousal, and emotional regulation, and has been reported to be associated with multiple sclerosis, essential tremors, and neurodegenerative diseases such as Parkinson's disease. In addition, it has been reported that iron deposits in the thalamus can cause depressive symptoms with age. Although there are discrepancies between studies, it can be deduced that the thalamus region has a clear effect on neurological disorders due to a strong relationship between the thalamus and neurological functions such as emotional control and processing. Through tractography analysis, the connectivity between the detailed areas of each subcortical region was investigated in the form of a matrix, showing strong connectivity and weak interhemispheric connectivity. In the 59> group, the WM connectivity of thalamus was found to be weaker than those of the two groups. Comparisons between the two groups showed that the young groups (10-39 and 40-59) had higher connection intensity than the 59> group and that statistically significant differences in 3 connection pathways were found in each hemisphere. A decrease in thalamus-related connection strength in aging has shown that it can affect emotional and neurological disorders such as anxiety and depression, and network measurements can help assess cognitive impairment across clinical conditions.

• Journal of Radiation Industry
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• v.17 no.4
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• pp.397-403
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• 2023

The purpose of this study is to obtain brain MRI images through Heavenly T₂ FLAIR and DWI techniques to find out strengths and weaknesses of each image. Data were analyzed on 13 normal people and 17 brain tumor patients. Philips Ingenia 3.0TCX was used as the equipment used for the inspection, and 32 Channel Head Coil was used to acquire data. Using Image J and Infinity PACS Data, 3mm² of gray matter, white matter, cerebellum, basal ganglia, and tumor areas were set and measured. Quantitative analysis measured SNR and CNR as an analysis method, and qualitative analysis evaluated overall image quality, lesion conspicuity, image distortion, susceptibility artifact and ghost artifact on a 5-point scale. The statistical significance of data analysis was that Wilcox-on Signed Rank Test and Paired t-test were executed, and the statistical program used was SPSS ver.22.0 and the p value was less than 0.05. In quantitative analysis, the SNR of gray matter, white matter, cerebellum, basal ganglia, and tumor of Heavily T₂ FLAIR is 41.45±0.13, 40.52±0.45, 41.44±0.51, 40.96±0.09, 35.28±0.46 and the CNR is 15.24±0.13, 16.75±0.23, 16.28±0.41, 15.83±0.17, 16.63±0.51. In DWI, SNR is 32.58±0.22, 36.75±0.17, 30.21±0.19, 35.83±0.11, 43.29±0.08, and CNR is 13.14±0.63, 14.21±0.31, 12.95±0.32, 11.73±0.09, 17.56±0.52. In normal tissues, Heavenly T₂ FLAIR obtained high results, but in disease evaluation, high results were obtained at DWI, b=1000 (p<0.05). In addition, in the qualitative analysis, overall image quality, lesion conspicuity, image distortion, susceptibility artifact and ghost artifact aspects of the Heavily T₂ FLAIR were evaluated, and 3.75±0.28, 2.29±0.24, 3.86±0.23, 4.08±0.21, 3.79±0.22 values were found, respectively, and 2.53±0.39, 4.13±0.29, 1.90±0.20, 1.81±0.21, 1.52±0.45 in DWI. As a result of qualitative analysis, overall image quality, image distortion, susceptibility artifact and ghost artifact were rated higher than DWI. However, DWI was evaluated higher in lesion conspicuity (p<0.05). In normal tissues, the level of Heavenly T₂ FLAIR was higher, but the DWI technique was higher in the evaluation of the disease (tumor). The two results were necessary techniques depending on the normal site and the location of the disease. In conclusion, statistically significant results were obtained from the two techniques. In quantitative and qualitative analysis, the two techniques had advantages and disadvantages, and in normal and disease evaluation, the two techniques produced useful results. These results are believed to be educational data for clinical basic evaluation and MRI in the future.

• Korean Journal of Cognitive Science
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• v.18 no.2
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• pp.159-178
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• 2007

Lee & Kang (2002) showed that simultaneous phonological rehearsal significantly delayed the performance of multiplication but not subtraction, whereas holding an image in the memory delayed subtraction but not multiplication. This result indicated that arithmetic function is related to working memory in a subsystem-specific manner. The aim of the current study was to examine the neural correlates of previous finding using fMRI. For this goal, dual task conditions that required suppression or no suppression were manipulated. In general, several areas were more activated in the interference conditions than in the less interference conditions, although both conditions were dual condition. More important finding is that the specific areas activated in the phonological suppression rendition were right inferior frontal gyrus, left angular, and inferior parietal lobule, while the areas activated in the other condition were mainly in the right superior temporal gyrus and anterior cingulate gyrus. Furthermore, the areas activated in the phonological or visual less suppression condition were right medial frontal gyrus, left middle frontal gyrus, and bilateral medial frontal gyri, anterior cingulate cortices, and parahippocampal gyri, respectively. These results revealed that sharing the processing code invokes interference, and its neural basis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.178-184
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• 2017

This study was performed on 16 patients diagnosed with tsutsugamushi disease and cerebral infarction from January 2007 to December 2015. An acute cerebral infarction was diagnosed by brain MRI and MRA. Tsutsugamushi disease was diagnosed using a polymerase chain reaction. To distinguish the difference between the generalized cerebral infarction and infarction with tsutsugamushi disease, the blood pressure and body temperature were measured uponadmission. In general, the blood pressure increases during an acute cerebral infarction. Interestingly, in this study, 12 patients showed a systolic blood pressure less than 130 mmHg uponadmission. The location of the cerebral infarction and whether single or multiple cerebral infarction were examined. Thirteen patients had a cerebral infarction in anterior circulation and 3 patients developed in posterior circulation. To evaluate the coagulation disorders, prothrombin time (PT), activated partial thromboplastin time (aPTT), D-dimer, fibrinogen, fibrin degradation product (FDP). D-dimer, which is generally known to increase in an acute cerebral infarction, showed a significant increase in the 13 patients. Fibrin degradation products (FDP) showed a significant increase in 15 patients. The pathophysiological mechanism of tsutsugamushi disease is known as vasculitis, which may result in an endothelial cell injury and proliferation of the endothelial wall, which may lead to a cerebral infarction accompanied by coagulopathy. Without endothelial cell damage and proliferation, a vasospasm caused by vasculitis may cause vasoconstriction and cerebral infarction.