• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.676-687
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• 2020

Purpose To analyze the altered brain regions and intrinsic brain activity patterns in trauma-exposed firefighters without posttraumatic stress disorder (PTSD). Materials and Methods Resting-state functional MRI (rsfMRI) was performed for all subjects. Thirty-one firefighters over 40 years of age without PTSD (31 men; mean age, 49.8 ± 4.7 years) were included. Twenty-six non-traumatized healthy controls (HCs) (26 men; mean age, 65.3 ± 7.84 years) were also included. Voxel-based morphometry was performed to investigate focal differences in the brain anatomy. Seed-based functional connectivity analysis was performed to investigate differences in spontaneous brain characteristics. Results The mean z-scores of the Seoul Verbal Learning Test for immediate and delayed recall, Controlled Oral Word Association Test (COWAT) score for animals, and COWAT phonemic fluency were significantly lower in the firefighter group than in the HCs, indicating decreased neurocognitive function. Compared to HCs, firefighters showed reduced gray matter volume in the left superior parietal gyrus and left inferior temporal gyrus. Further, in contrast to HCs, firefighters showed alterations in rsfMRI values in multiple regions, including the fusiform gyrus and cerebellum. Conclusion Structural and resting-state functional abnormalities in the brain may be useful imaging biomarkers for identifying alterations in trauma-exposed firefighters without PTSD.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.395-405
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• 2014

Objective: The aim of this study is to investigate 1) somatotopic arrangement of the second and third fingers in SI area 2) difference of neural activation in the SI area produced by stimulation with different frequencies 3) correlation between the intensity of tactile perception by different stimulus intensity and the level of brain activation measurable by means of fMRI. Background: Somatosensory cortex can obtain the information of environmental stimuli about "where" (e.g., on the left palm), "what" (e.g., a book or a dog), and "how" (e.g., scrub gently or scrub roughly) to organism. However, compared to visual sense, the neural mechanism underlying the processing of specific electrotactile stimulus is still unknown. Method: 10 right-handed subjects participated in this study. Non-painful electrotactile stimuli were delivered to two different finger tips of right hand. Functional brain images were collected from 3.0T MRI using the single-shot EPI method. The scanning parameters were as follows: TR and TE were 3000, 35ms, respectively, flip angle 60, FOV $24{\times}24cm$, matrix size $64{\times}64$, slice thickness 4mm (no gap). SPM5 was used to analyze the fMRI data. Results: Significant activations produced by the stimulation were found in the SI, SII, the subcentral gyrus, the precentral gyrus, and the insula. In all participants, statistically significant activation was observed in the contralateral SI area and the bilateral SII areas by the stimulation on the fingers but ipsilaterally dominant. The SI area representing the second finger generally located in the more lateral and inferior side than that of the third finger across all the subjects. But no difference in brain area was found for the stimulation of the fingers by different frequencies. And two typical patterns were observed on the relationship between the perceived psychological intensity and the amount of voxels in the primary sensory cortex during the stimulation. Conclusion: It was possible to discriminate the representation sites in the SI by electrotactile stimulation of digit2 and digit3. But we could not find the differences of the brain areas according to different stimulation frequencies from 3 to 300Hz. Application: The results of the study can provide a deeper understanding of somatosensory cortex and offer the information for tactile display for blinds.

• Clinical and Experimental Pediatrics
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• v.61 no.2
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• pp.64-67
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• 2018

We report the case of a 12-year-old girl who had mild encephalopathy with a reversible splenial lesion (MERS) associated with acutepyelonephritis caused by Escherichia coli. The patient was admitted with a high fever, and she was diagnosed with acute pyelonephritis based on pyuria and the results of urine culture, which detected cefotaxime-sensitive E. coli. Although intravenous cefotaxime and tobramycin were administered, her fever persisted and her C-reactive protein level increased to 307 mg/L. On day 3 of admission, she demonstrated abnormal neuropsychiatric symptoms, such as delirium, ataxia, and word salad. Magnetic resonance imaging (MRI) of the brain performed on day 4 showed marked hyperintensities in the bilateral corpus callosum and deep white matter on diffusion-weighted images, with corresponding diffusion restriction on apparent diffusion coefficient mapping. No abnormalities or pathogens were detected in the cerebrospinal fluid; however, lipopolysaccharides (LPS, endotoxin) were detected in plasma (41.6 pg/mL), associated with acute neurological deterioration. Her clinical condition gradually improved, and no neurological abnormalities were observed on day 6. Follow-up brain MRI performed 2 weeks later showed near-disappearance of the previously noted hyperintense lesions. In this patient, we first proved endotoxemia in a setting of MERS. The release of LPS following antibiotic administration might be related to the development of MERS in this patient. The possibility of MERS should be considered in patients who present with acute pyelonephritis and demonstrate delirious behavior.

• The Korean Journal of Pain
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• v.11 no.2
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• pp.338-342
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• 1998

Postural headache due to spontaneous intracranial hypotension occurs without any diagnostic lumbar puncture, myelography, cranial or spinal injury, or spinal anesthesia. The clinical characteristics of the syndrome are disappearance of the headache or a notable decrease in its severity with recumbency, the finding of meningeal enhancement and subdural fluid collection on brain MRI, the pleocytosis and the increased CSF protein concentration. We report a case of a 40-year-old woman who exhibited the signs and symptoms of postural headache due to low CSF pressure. Her headache started suddenly at the occiput and radiated to frontal head. Magnetic resonance imaging (MRI) of her brain showed enhancement of the meninges and subdural fluid collection. Intrathecal radionuclide cisternography showed the delayed appearance of the isotope in the cranium and the minimal CSF leak at the left upper thoracic region. Her headache was relieved completely after a lumbar (L2-L3) epidural injection of 12 ml of autologous blood and remained asymptomatic.

• Korean Journal of Cognitive Science
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• v.21 no.1
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• pp.77-93
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• 2010

The aim of this study was to identify neural correlates underlying the detection of faux pas, a test of theory of mind (ToM), in Korean healthy adults. Using functional magnetic resonance imaging, we compared the brain activities associated with faux pas stories and the activities associated with control stories. Faux pas stories compared with the control stories produced activations bilaterally in the superior frontal gyrus (BA 9) and in the precuneus (BA 7). The left medial frontal gyrus (BA 9), the left superior temporal gyrus (BA 38), the left inferior temporal gyrus (BA 20) and the right inferior parietal lobule (BA 40), the right postcentral gyrus (BA 1), the right lingual gyrus (BA 18), the right transverse temporal gyrus (BA 41) were also activated. The orbitofrontal cortex and the amygdala were not found to be involved in the detection of faux pas. This result suggests that brain activations associated with ToM are dependent on the type of mental state drawn by the task.

• Journal of Korean Neurosurgical Society
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• v.53 no.5
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• pp.312-315
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• 2013

Aspergillosis in the central nervous system (CNS) is a very rare disease in immune-competent patients. There was a case of a healthy man without a history of immune-compromised disease who had invasive aspergillosis with unusual radiologic findings. A 48-year-old healthy man with diabetes mellitus, presented with complaints of blurred vision that persisted for one month. Brain magnetic resonance imaging (MRI) showed multiple nodular enhancing lesions on the right cerebral hemisphere. The diffusion image appeared in a high-signal intensity in these areas. Cerebrospinal fluid examination did not show any infection signs. An open biopsy was done and intraoperative findings showed grayish inflammatory and necrotic tissue without a definitive mass lesion. The pathologic result was a brain abscess caused by fungal infection, morphologically aspergillus. Antifungal agents (Amphotericin B, Ambisome and Voriconazole) were used for treatment for 3 months. The visual symptoms improved. There was no recurrence or abscess pocket, but the remaining focal enhanced lesions were visible in the right temporal and occipital area at a one year follow-up MRI. This immune-competent patient showed multiple enhancing CNS aspergillosis in the cerebral hemisphere, which had a good outcome with antifungal agents.

• Anxiety and mood
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• v.14 no.2
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• pp.63-70
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• 2018

It has been suggested that aberrant self-referential processing (SRP) is one of the important components of the explanatory models of social anxiety disorder (SAD). The default mode network (DMN), which reflects intrinsic brain functions, is known to play a critical role in SRP. Recently, resting state functional magnetic resonance imaging (fMRI) research on the functional connectivity in the brain network has gained greater attention as a tool to elucidate the neurobiological basis of various psychiatric disorders. We reviewed resting state fMRI studies that investigated the resting state functional connectivity (RSFC) of the DMN in SAD. Despite of the heterogeneity of the analytic methods and occasional negative findings, most studies consistently reported abnormalities of RSFC within the DMN, suggesting that the DMN may be significant neural correlates of aberrant SRP in SAD. Also, changes in RSFC of the DMN are associated with clinical improvements of therapeutic interventions. Moreover, emerging findings provide the basis for potential use of RSFC as a complementary method in diagnosis of SAD. Ongoing and future research to investigate RSFC of the DMN could broaden our understanding regarding the neurobiological basis of SAD, and contribute to the development of novel treatments for SAD.

• Journal of the Korean Society of Radiology
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• v.83 no.3
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• pp.486-507
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• 2022

Cerebral small vessel disease (CSVD) includes vascular lesions detected on brain MRI, such as white matter hyperintensities, lacunar infarctions, microbleeds, or enlarged perivascular spaces. There is accumulating evidence that vascular changes may play an important role in development of Alzheimer's disease (AD), and CSVD lesions detected on brain MRI were reported to be associated with β-amyloid and tau proteins accumulation. As the vascular contribution has therapeutic potential, it is important to understand the association of CSVD with AD and AD biomarkers. This review begins with a brief introduction of AD and AD biomarkers, explains the association between AD and vascular changes, and then details the pathogenesis and MR imaging findings of CSVD. Afterwards, we discuss the association of CSVD with AD and AD biomarkers.

• Journal of the Korean Society of Radiology
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• v.84 no.5
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• pp.1140-1145
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• 2023

Cerebral amyloid angiopathy-related inflammation (CAA-RI) is an encephalopathy caused by inflammation of β-amyloid peptide deposition in cerebrovascular vessels. It is a rare disease that mainly occurs in the elderly and is characterized by rapidly progressive dementia, headache, seizures, and focal neurologic deficits. CAA-RI can demonstrate characteristic brain MRI findings and can be reversed by steroids or other immunosuppressive therapies. Here, we report a case of CAA-RI, which was initially misdiagnosed as a subacute infarction but was diagnosed while reviewing follow-up brain MRI images, and spontaneous remission was achieved.

• Investigative Magnetic Resonance Imaging
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• v.6 no.1
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• pp.21-27
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• 2002

Purpose : To evaluate diffusion-weighted imaging findings of intracerebral hematoma according to the time sequence. Materials and methods : Seventeen patients with intracerebral hematoma were studied. Diffusion weighted images using 1.5 tesla MRI machine were obtained with b-value of $1000{\;}sec/\textrm{mm}^2$. The patients were grouped as hyperacute stage(within 12 hours, 5 patients), acute stage(within 3 days, 4 patients), subacute stage(within 3 weeks, 4 patients), and chronic stage(after 3 weeks,4 patients). The signal intensities were analysed as bright, high, iso, low and dark at the central and peripheral portions of the hematoma in each stage, and compared with those of T2 and T1 weighted images. Results : The signal intensities of the central and peripheral portion of the intracerebral hematoma on diffusion-weighted images were high and dark in hyperacute stage, dark and high-bright in acute stage, and high-bright and dark in subacute and chronic stages. The patterns of signal change of hematoma on diffusion-weighted image according to the time sequence were similar to those on T2-weighted image, but changed early and prominently. Conclusion : The intracerebral hematoma on diffusion-weighted image showed unique central and peripheral signal intensity according to the time sequence. Central portions show high to bright signals in hyperacute, subacute and chronic stage, and dark signal in acute stage, and peripheral portions show dark signals in hyperacute, subacute and chronic stage, and high to bright signal in acute stage.