• Journal of the Institute of Convergence Signal Processing
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• v.12 no.4
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• pp.267-273
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• 2011

In this paper, we proposed the method to detect brain tumor region in MR images. Our method is composed of 3 parts, detection of tumor slice, detection of tumor region and tumor boundary detection. In the tumor slice detection step, a slice which contains tumor regions is distinguished using symmetric analysis in 3D brain volume. The tumor region detection step is the process to segment the tumor region in the slice distinguished as a tumor slice. And tumor region is finally detected, using spatial feature and symmetric analysis based on the cluster information. The process for detecting tumor slice and tumor region have advantages which are robust for noise and requires less computational time, using the knowledge of the brain tumor and cluster-based on symmetric analysis. And we use the level set method with fast marching algorithm to detect the tumor boundary. It is performed to find the tumor boundary for all other slices using the initial seeds derived from the previous or later slice until the tumor region is vanished. It requires less computational time because every procedure is not performed for all slices.

• Journal of Korean Orthopaedic Sports Medicine
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• v.9 no.1
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• pp.16-21
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• 2010

The prevalence of overuse syndrome in the lower extremity including chronic compartment syndrome and stress fracture is increasing with popularity of sports activities. Chronic compartment syndrome is defined as elevation of the interstitial pressure during exertional activities in a closed osseofascial compartment that results in microvascular compromise and operative procedures can be necessary if conservative treatments fail. Stress fracture can be classified as fatigue and insufficiency fracture; stress fracture occurs by repeated strain under abnormal conditions from the patient's activity whereas insufficiency fracture does by those from a process intrinsic to the bone. Most stress fractures occur in the lower extremity, most commonly in the tibial region. Fatigue fractures begin in athletes with the change in their training programs. The radiographic findings are usually diagnostic or at least strongly suggestive and MRI has proven to be a beneficial diagnostic tool for difficult diagnostic cases. Fatigue fractures are treated with a decrease in activity, but surgical procedure may be necessary in those in anterior cortex of the tibial diaphysis.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.44-52
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• 2024

PSM(process safety management), introduced for the purpose of managing complex chemical processes, has contributed to the prevention of chemical accidents, but has recently revealed its limitations. Recently, major industrial accidents have increased, and in particular, Serious Industrial Accidents have increased rapidly in non-routine works since 2020. It is time for an effective PSM operation plan. This study examined that FRAM can be effectively used in the PSM operation process by using FRAM (Functional Resonance Analysis Method), a useful technique for understanding and predicting human error and accident occurrence processes by modeling nonlinear and complex interactions, to analyze accident cases that occurred in non-routine works, and to further analyze the process of performing general PSM non-routine works.

• Investigative Magnetic Resonance Imaging
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• v.6 no.1
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• pp.47-54
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• 2002

Purpose : Hippocampal atrophy is one of the characteristic pathologic findings of hippocampal sclerosis, for which MR imaging of the hippocampus is essential in the evaluation of hippocampal sclerosis. The purpose of this study is to present the normal MR volumetric data of the hippocampus in normal adult Korean and to compare those with MR volumetric data of hippocampus in patients with hippocampal s-clerosis, providing the diagnostic volume criteria of the hippocampal atrophy. Materials and methods : MR volumetry was performed in 30 normal adults and 28 patients with temporal lobe epilepsy whose final diagnosis was hippocampal sclerosis. The volumetric data were compared between sexes, right and left sides, and normal and abnormal hippocampus, and the volume criteria for the diagnosis of hippocampal atrophy was determined. Results : The mean $volumes({\pm}standard$ deviation) of normal Korean adult were $2.20{\pm}0.73\textrm{cm}^3$ (right) and $2.17{\pm}0.72\textrm{cm}^3$ (left) in male and $2.27{\pm}0.47{\;}\textrm{cm}^3$ (right) and $2.23{\pm}0.48\textrm{cm}^3$ (left) in female. The mean right-left differences were $0.14{\pm}0.11\textrm{cm}^3$ and $0.19{\pm}0.13\textrm{cm}^3$ in male and female, respectively. The MR volumetry showed no significant statistical differences between sexes and between right and left. The mean volume and standard deviation of the hippocampus in hippocampal sclerosis patients was $1.46{\pm}0.60{\;}\textrm{cm}^3$, and the right-left difference was $0.51{\pm}0.41\textrm{cm}^3$, In comparison of two volume distributions between normal adult group and hippocampal sclerosis patients group, the reasonable diagnostic volume criteria was $0.4{\;}\textrm{cm}^3$ as right-left volume difference, in which the sensitivity and specificity are 0.61 and 0.90. In all patients with right-left volume difference more than $0.4{\;}\textrm{cm}^3$, visual determination of unilateral hippocampal atrophy was possible. Conclusion : The MR-based hippocampal volumetry is a useful add-on of visual MR diagnosis, only when visual diagnosis of hippocampal sclerosis is difficult.

• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.16-24
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• 2012

Purpose : The purpose of this study was to determine whether there is a significant correlation between vertebral marrow fat fraction measured using Dixon quantitative chemical shift MRI (QCSI) and BMD on dual-energy X-ray absorptiometry (DXA). Materials and Methods: This retrospective study included 68 healthy individuals [mean age, 50.7 years; range, 25-76; male/female (M/F) = 36/32] who underwent DXA of the L-spine and whole body MRI including QCSI of the L-spine and chemical shift MRI of the liver. The enrolled individuals were divided into subgroups according to sex and T-score [i.e., normal bone density (M/F=27/23) and osteopenia (M/F=9/9)]. Vertebral marrow (Dixon QCSI, TR/TE 10.2/4.8 ms) and hepatic fat fractions (chemical shift technique, TR/TE 110/4.9 and 2.2 ms) were calculated on MRI. We evaluated whether there were significant differences in age, body mass index (BMI), vertebral marrow fat fraction, or hepatic fat fraction among the subgroups. Whether or not the participant had reached menopause was also evaluated in females. The correlations among variables (i.e., age, BMI, vertebral marrow and hepatic fat fractions, BMD) were evaluated using Spearman's correlation method. Results: There were no significant differences in age, BMI, or vertebral marrow and hepatic fat fractions between the two male subgroups (normal bone density vs. osteopenia). In female subjects, mean age in the osteopenic subgroup was greater than that in the normal subgroup (p=0.01). Presence of menopause was more common in the osteopenic subgroup [77.8% (7/9)] than the normal subgroup [26.1% (6/23), p<0.05]. The other variables showed no significant difference between female subgroups. The only significant correlation with marrow fat fraction after partial correlation analysis was that with age in the female subjects (r=0.43, p<0.05). Conclusion: The vertebral marrow fat fraction calculated using the Dixon QCSI does not precisely reflect the mild decrease in BMD for either sex.

• Investigative Magnetic Resonance Imaging
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• v.9 no.1
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• pp.43-49
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• 2005

A few studies have shown that the function of fusiform face area is selectively involved in the perception of faces including a race difference. We investigated the neural substrates of the face-selective region called fusiform face area in the ventral occipital-temporal cortex and same-race memory superiority in the fusiform face area by the event-related fMRI. In our fMRI study, subjects (Oriental-Korean) performed the implicit distinction of the race while they consciously made familiar-judgments, regardless of whether they considered a face as Oriental-Korean or European-American. For race distinction as an implicit task, the fusiform face areas (FFA) and the right parahippocampal gyrus had a greater response to the presentation of Oriental-Korean faces than for the European-American faces, but in the conscious race distinction between Oriental-Korean and European-American faces, there was no significant difference observed in the FFA. These results suggest that different activation in the fusiform regions and right parahippocampal gyrus resulting from superiority of same-race memory could have implicitly taken place by the physiological processes of face recognition.

• Investigative Magnetic Resonance Imaging
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• v.7 no.2
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• pp.132-136
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• 2003

Purpose : To evaluate the usefulness of breath-hold T2-weighted MR imaging in patients with myocardial infarction. Materials and Methods : We investigated 11 patients with myocardial infarction who shown delayed enhancement on MR imaging. Infarcted myocardium on T2-weighted MR imaging was classified as high, iso, and low signal area comparing with normal myocardium. The intensity and transmural extent of infracted myocardium was also analyzed. On the basis of clinical information, the stage of infracted myocardium on T2-weighted MR imaging was assessed. Results : It was observed high signal area in 12 segments of 5 patients, low in 12 segments of 6 patients on T2-weighted MR imaging. The high signal intensity of infarcted myocardium was shown as $175{\pm}9\%$ comparing with that of the normal myocardium, low signal intensity as $73{\pm}5\%\;(p\;<\;0.05)$. In the evaluation of transmural extent, the high signal areas on T2-weighted MR imaging were larger than infarct area on delayed enhancement imaging $(100\%\;vs.49\%{\pm}17\%)$, whereas low signal areas on T2-weighted MR imaging correlated. High signal area was visualized on T2-weighted MR imaging within 11 days, whereas low-signal area was seen after 7 months. Conclusion : Breath-hold T2-weighted MR imaging is useful in the evaluation of stage as well as edema and fibrous scar in patients with myocardial infarction.

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.63-69
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• 2006

Purpose : Marrow edema and fatty degeneration of the hip joint bones could be initial and late signs in hip joint and its bone diseases respectively, which might be differentiated from age-related marrow conversion pattern. So authors have investigated normal marrow conversion pattern of the femur and acetabulum around the hip joints. Materials and methods : Three coronal MR images of 288 hip joint bones in 144 subjects, aged 2 days to 76 years divided to 8 groups every 10 years, were retrospectively analysed for the location and appearance of the converted yellow marrow. The converted yellow marrow were divided to head, neck, and trochanter in the proximal femur and below and above 50% in acetabulum of the hip. Results : The most common type of marrow conversion is the converted yellow marrow in the entire proximal femur and below 50% of acetabulum of the hip. We observed the start of marrow conversion in just before and after 2 years old and stopped at just before and after 20 years old. Conclusion : The understanding of age-related marrow conversion pattern of the hip joint bones would provide some information for differentiation from pathologic condition of them such as edema, fatty degeneration, metastasis, or leukemia.

• The korean journal of orthodontics
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• v.35 no.5 s.112
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• pp.398-407
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• 2005

The present study was conducted to examine the morphometrics and function of the disk on both sides among patients with facial asymmetry (FA) and to elucidate plausible correlations between internal derangement (ID) and FA. The sample was composed of 10 males and 27 females with FA. The disk status of all subjects was evaluated by bilateral high resolution magnetic resonance scans in the sagittal (closed and open) and coronal (closed) planes. Five types of disk displacement were identified accordingly. The disk function was diagnosed as normal disk function, disk displacement with reduction, and disk displacement without reduction. The disk shape on sagittal MRI in closed position was classified as bi-concave, biplanar, funnel/hemiconvex, and deformed. The disk position, translation and rotation were also measured. The difference between the shifted side and non-shifted side was analyzed by statistical analysis. Approximately $70\%$ of the patients in the present study showed unilateral or bilateral ID. It was found that anterior disk displacements (ADD), especially rotational ADD, occurred more frequently in the shifted side, while normal disk position was observed mainly in the non-shifted side (p<0.01). The disk of the shifted side showed significantly deformed configuration and inferior-anterior disk position. However, the disk of the non-deviated side showed hyper-mobility during jaw opening movement. These results demonstrate that in FA patients, the disks status of the shifted side is different from that of the non-shifted side, a phenomenon that could be correlated to facial asymmetry.

• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.184-196
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• 2024

Purpose We investigated potentially promising imaging findings and their combinations in the evaluation of cognitive decline. Materials and Methods This retrospective study included 138 patients with subjective cognitive impairments, who underwent brain MRI. We classified the same group of patients into Alzheimer's disease (AD) and non-AD groups, based on the neuropsychiatric evaluation. We analyzed imaging findings, including white matter hyperintensity (WMH) and cerebral microbleeds (CMBs), using the Kruskal-Wallis test for group comparison, and receiver operating characteristic (ROC) curve analysis for assessing the diagnostic performance of imaging findings. Results CMBs in the lobar or deep locations demonstrated higher prevalence in the patients with AD compared to those in the non-AD group. The presence of lobar CMBs combined with periventricular WMH (area under the ROC curve [AUC] = 0.702 [95% confidence interval: 0.599-0.806], p < 0.001) showed the highest performance in differentiation of AD from non-AD group. Conclusion Combinations of imaging findings can serve as useful additive diagnostic tools in the assessment of cognitive decline.