• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.441-445
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• 2000

This study is to segment white matter, gray matter, and cerebrospinal fluid(CSF) on a brain MR image of coronal section and to calculate the volume of each. First, we segmented the whole region of a brain from a black colored background, a skull and a fat layer. Then, we calculated the partial volume of each component, which was present in scanning finite thickness, with the arithmetical analysis of gray value from the internal region of a brain showing the blurring effects on the basis of the MR image forming principle. Calculated partial volumes of white matter, gray matter and CSF were used to determine the threshold for the segmentation of each component on a brain MR image showing the blurring effects. Finally, the volumes of segmented white matter, gray matter, and CSF were calculated. The result of this study can be used as the objective diagnostic method to determine the degree of brain atrophy of patients who have neurodegenertive diseases such as Alzheimer’s disease and cerebral palsy.

• Investigative Magnetic Resonance Imaging
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• v.22 no.2
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• pp.131-134
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• 2018

Susceptibility-weighted imaging (SWI) is well known for detecting the presence of hemorrhagic transformation, microbleeds and the susceptibility of vessel signs in acute ischemic stroke. But in some cases, it can provide the tissue perfusion state as well. We describe a case of a patient with hyperacute ischemic infarction that had a slightly hypodense, patchy lesion at the left thalamus on the initial SWI, with a left proximal posterior cerebral artery occlusion on a magnetic resonance (MR) angiography and delayed time-to-peak on an MR perfusion performed two hours after symptom onset. No obvious abnormal signals at any intensity were found on the initial diffusion-weighted imaging (DWI). On a follow-up MR image (MRI), an acute ischemic infarction was seen on DWI, which is the same location as the lesion on SWI. The hypointensity on the initial SWI reflects the susceptibility artifact caused by an increased deoxyhemoglobin in the affected tissue and vessels, which reflects the hypoperfusion state due to decreasing arterial flow. It precedes the signal change on DWI that reflects a cytotoxic edema. This case highlights that, in some hyperacute stages of ischemic stroke, hypointensity on an SWI may be a finding before the hyperintensity is seen on a DWI.

• Journal of the Korean Society of Radiology
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• v.83 no.5
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• pp.1147-1152
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• 2022

Presumed idiopathic intracranial hypertension (IIH) is a disorder of elevated intracranial pressure with unknown etiology, and 10% of cases occur secondarily to cerebral venous sinus thrombosis (CVST). CVST may be underestimated when findings of IIH are missed in a normal-weight patient without risk factors of coagulopathy. Here, we present a case of CVST that mimics a neurogenic tumor in the hypoglossal canal in a normal-weight patient without risk factors of coagulopathy.

• Clinical and Experimental Pediatrics
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• v.48 no.11
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• pp.1232-1238
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• 2005

Purpose : Though more than 15 years have passed after introduction of Lorenzo's oil therapy in X-linked adrenoleukodystrophy(ALD), its efficacy is still fully not known. In patients who already have neurologic symptoms, most reports indicate that the neurologic disability continues to increase. We evaluated its efficacy in X-linked ALD patients. Methods : Four patients who were treated with Lorenzo's oil for at least 12 months were enrolled from 1996 to 2003. During treatment, changes of neurologic symptoms, brain magnetic resonance imaging(MRI) findings, and serum saturated very long-chain fatty acid(C26:0) were assessed. Results : Two patients with childhood cerebral ALD had progression of neurologic symptoms and MRI lesions during treatment. One asymptomatic patient developed childhood cerebral ALD after six year treatment of Lorenzo's oil. One "Addison only" patient remained neurologically intact after three years. During Lorenzo's oil therapy, serum C26:0 levels which had increased at diagnosis decreased in all four patients. Conclusion : Treatment with Lorenzo's oil did not prevent disease progression in childhood cerebral ALD patients who were already symptomatic. Long term follow up will be needed in asymptomatic ALD including "Addison only" to reveal the efficacy of Lorenzo's oil.

• Investigative Magnetic Resonance Imaging
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• v.12 no.1
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• pp.20-26
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• 2008

Purpose : To present the T1 and T2 relaxation times of the major cerebral metabolites at 1.5T and 3.0T and compare those between 1.5T and 3.0T. Materials and Methods : Using the phantom containing N-acetyl aspartate (NAA), Choline (Cho), and Creatine (Cr) at both 1.5T and 3.0T MRI, the T1 relaxation times were calculated from the spectral data obtained with 5000 ms repetition time (TR), 20 ms echo time (TE), and 11 different mixing time (TM)s using STEAM (STimulated Echo-Acquisition Mode) method. The T2 relaxation times were obtained from the spectral data obtained with 3000 ms TR and 5 different TEs using PRESS (Point-RESolved Spectroscopy) method. The T1 and T2 relaxation times obtained at 1.5T were compared with those of 3.0T. Results : The T1 relaxation times of NAA were $2293\;{\pm}\;48\;ms$ at 1.5T and $2559\;{\pm}\;124\;ms$ at 3.0T (11.6% increase at 3.0T). The T1 relaxation times of Cho were $2540\;{\pm}\;57\;ms$ at 1.5T and $2644\;{\pm}\;76\;ms$ at 3.0T (4.1% increase at 3.0T). The T1 relaxation times of Cr were $2543\;{\pm}\;75\;ms$ at 1.5T and $2665\;{\pm}\;94\;ms$ at 3.0T (4.8% increase). The T2 relaxation times of NAA were $526\;{\pm}\;81\;ms$ at 1.5T and $468\;{\pm}\;74\;ms$ at 3.0T (11.0% decrease at 3.0T). The T2 relaxation times of Cho were $220\;{\pm}\;44ms$ at 1.5T and $182\;{\pm}\;35\;ms$ at 3.0T (17.3% decrease at 3.0T). The T2 relaxation times of Cr were $289\;{\pm}\;47\;ms$ at 1.5T and $275\;{\pm}\;57\;ms$ at 3.0T (4.8% decrease at 3.0T). Conclusion : The T1 relaxation times of the major cerebral metabolites (NAA, Cr, Cho), which were measured at the phantom, were 4.1%-11.6% longer at 3.0T than at 1.5T. The T2 relaxation times of them were 4.8%-17.3% shorter at 3.0T than at 1.5T. To optimize MR spectroscopy at 3.0T, TR should be lengthened and TE should be shortened.

• Korean Journal of Radiology
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• v.23 no.2
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• pp.226-236
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• 2022

Objective: This study aimed to explore the myelin volume change in patients with mild traumatic brain injury (mTBI) with post-concussion syndrome (PCS) using a multidynamic multiecho (MDME) sequence and automatic whole-brain segmentation. Materials and Methods: Forty-one consecutive mTBI patients with PCS and 29 controls, who had undergone MRI including the MDME sequence between October 2016 and April 2018, were included. Myelin volume fraction (MVF) maps were derived from the MDME sequence. After three dimensional T1-based brain segmentation, the average MVF was analyzed at the bilateral cerebral white matter (WM), bilateral cerebral gray matter (GM), corpus callosum, and brainstem. The Mann-Whitney U-test was performed to compare MVF and myelin volume between patients with mTBI and controls. Myelin volume was correlated with neuropsychological test scores using the Spearman rank correlation test. Results: The average MVF at the bilateral cerebral WM was lower in mTBI patients with PCS (median [interquartile range], 25.2% [22.6%-26.4%]) than that in controls (26.8% [25.6%-27.8%]) (p = 0.004). The region-of-interest myelin volume was lower in mTBI patients with PCS than that in controls at the corpus callosum (1.87 cm³ [1.70-2.05 cm³] vs. 2.21 cm³ [1.86-3.46 cm³]; p = 0.003) and brainstem (9.98 cm³ [9.45-11.00 cm³] vs. 11.05 cm³ [10.10-11.53 cm³]; p = 0.015). The total myelin volume was lower in mTBI patients with PCS than that in controls at the corpus callosum (0.45 cm³ [0.39-0.48 cm³] vs. 0.48 cm³ [0.45-0.54 cm³]; p = 0.004) and brainstem (1.45 cm³ [1.28-1.59 cm³] vs. 1.54 cm³ [1.42-1.67 cm³]; p = 0.042). No significant correlation was observed between myelin volume parameters and neuropsychological test scores, except for the total myelin volume at the bilateral cerebral WM and verbal learning test (delayed recall) (r = 0.425; p = 0.048). Conclusion: MVF quantified from the MDME sequence was decreased at the bilateral cerebral WM in mTBI patients with PCS. The total myelin volumes at the corpus callosum and brainstem were decreased in mTBI patients with PCS due to atrophic changes.

• Clinical and Experimental Pediatrics
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• v.50 no.9
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• pp.891-895
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• 2007

Purpose : Acute disseminated encephalomyelitis (ADEM) is a demyelinating disease of the central nervous system and mostly develops after viral illness or vaccinations. We investigated the clinical differences and neurologic outcomes according to the distribution of the lesions on brain MRI. Methods : The study group was composed of 21 patients from January 1995 to August 2003 in Kyunghee University hospital. We grouped the patients according to the MRI findings as follows. Group I (14 cases): Multi- or unifocal lesions only in the cerebral white matter. Group II (7 cases): lesions in the gray matter with or without white matter involvement. Results : 1. Preceding events were as follows: no defined prodrome (38.1%), upper respiratory tract infection (28.6%), nonspecific febrile illness (19.0%), gastointestinal disturbance and vaccination. 2. Presenting symptoms were as follows: seizures (76.2%), headache/vomiting (47.6%), altered consciousness (38.1%), hemiparesis, cerebellar ataxia, visual disturbance and facial nerve palsy. 3. Laboratory findings were as follows: CSF pleocytosis (76.2%), leucocytosis (38.1%) and elevated CSF protein (28.6%). 4. Fifteen patients were recovered completely without neurological sequelae. Three patients in group I and 1 patient in group II had intractable seizures. Two patients in group I and 2 patients in group II had motor disturbance. Conclusion : There were no statistically significant differences in preceding events, presenting symptoms, and neurological outcomes according to the distribution of the lesions on brain MRI. However, the ADEM have quite diverse clinical manifestations and neuroimage findings. MRI plays an important role in making diagnosis of the patients who are suspected of ADEM.

• Clinical and Experimental Pediatrics
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• v.50 no.6
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• pp.588-591
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• 2007

Left ventricular thrombus is mainly caused by anterior myocardial infarction or severe cardiac wall dysfunction of the apex, and is rarely caused by a complication of acute myocarditis. A 12-year-old female who developed symptoms of motor dysphasia and incomplete hemiparesis of the right side was admitted to the hospital. The brain MRI taken on the day of her admission showed acute cerebral infarction in the left basal ganglia and the frontoparietal lobe. The echocardiogram showed a movable thrombus, which was $19{\times}28mm$ sized and located in the apex of the left ventricle. So in order to prevent further thromboembolic event we performed open cardiac surgery via the atrium and removed the thrombus of the left ventricle. After the removal of the thrombus her symptoms improved and she was discharged from the hospital. Thrombus formation in acute viral myocarditis are considered to be related with endocardial injury and blood flow stasis. Treatment with anticoagulants in left ventricular thrombosis may not be effective and may even cause a major thromboembolism. When the thrombus is laminar and fixed, one should consider anticoagulant therapy. But if the thrombus is pedunculated and movable, which means that there are higher possibilities of major embolism or there may be already one, one should consider surgical removal. We report a 12-year-old girl who required surgical removal of a left ventricular thrombus caused by acute viral myocarditis.

• Progress in Medical Physics
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• v.5 no.1
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• pp.55-66
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• 1994

After proving home-made imaging pulse sequences including tailored RF pulse by phantom, susceptibility-contrast-enhanced MR venograms of cat brain were obtained using tailored RF gradient-echo(TRGE) method. Sagittal MR imaging of the cat brain obtained by TRGE technique shows several veins, for example, dorsal sagittal sinus, straight sinus, vein of corpus callosum and internal cerebral vein, etc., compared with cats anatomical figure. Tailored RF waveform was generated by PASCAL language in ASPECT 3000 computer(Switzland, Bruker). Rectangular-shaped slice profile with bi-linear ramp function as phase distribution in the slice, at which maximum value was 2$\pi$, was fourier transformed to make tailored RF pulse. Experimental MR imaging parameters were TR/TE=205/10 msec, slice thickness TH=7mm, maxtrix size=256$\times$256, in-plane resolution=0.62$\times$0.31mm$^2$, and field of view(FOV)=8cm for both conventional gradient-echo(GE) imaging and TRGE imaging techniques.

• Journal of Korean Neurosurgical Society
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• v.43 no.6
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• pp.265-269
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• 2008

Objective : Outcome of gamma knife radiosurgery (GKS) in the consecutive 100 cases with cerebral arteriovenous malformations (AVMs) was analyzed. Methods : Data from initial 100 patients treated with GKS in the authors' institute were reviewed retrospectively. Spetzler-Martin grade at diagnosis were I in 18 patients, II in 27, III in 36, IV in 11, and V in 8. Thirty-five patients had experienced previous bleeding, 27 patients presented with seizure, and 31 patients presented with headache. The mean volume of the lesion was $4.3\;cm^3\;(0.1-29.3\;cm^3)$. The median radiation dose delivered to the margin was 20.0Gy (13-32Gy). Mean follow-up period was 37.5 months (5-63 months). Results : Angiographic follow-up was performed in 48 patients at least 2 years after GKS. Sixteen patients were lost in follow up following 2 years from GKS. Twenty-eight of 48 patients (58%) showed complete obliteration and 20 patients (42%) showed partial obliteration. Seven patients presented with post-GKS hemorrhage. Adverse radiation effect (ARE) was observed at follow-up MRI in 25 of 76 patients, and it was symptomatic in 5 patients. Complete obliteration was confirmed in 24 of 31 (77%) patients with volume less than $4\;cm^3$, meanwhile only 4 of 17 (24%) patients with volume of $4\;cm^3$ or more showed complete obliteration. Complete obliteration rate was 67% with 20Gy or higher marginal dose, 63% with 15-20 Gy, and 17% with less than 15Gy. Conclusion : GKS can provide high rates of obliteration with acceptable risk of morbidity in a subgroup of small AVMs. However, overall outcome in whole spectrum of AVMs, in which large proportion of cases have unfavorable characteristics for radiosurgery, is much worse. More effective therapeutic strategy needs to be developed for large AVMs that are difficult to be managed with current available treatment modalities.