• Investigative Magnetic Resonance Imaging
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• v.23 no.1
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• pp.65-69
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• 2019

Ramsay Hunt syndrome with the complication of encephalitis or meningoencephalitis is rarely reported and uncommon in immunocompetent patients. The radiological manifestations of such cases usually involve the cerebellum and brainstem or exhibit the absence of any abnormality. We report a case of a 78-year-old immunocompetent man hospitalized with Ramsay Hunt syndrome, who later developed meningoencephalitis. The cerebrospinal fluid-study excluded other causes of meningoencephalitis, and the clinical diagnosis indicated varicella zoster virus meningoencephalitis. Magnetic resonance imaging revealed increased signal intensities in the bilateral temporal lobe, midbrain, and pons on T2-weighted imaging, and T2 fluid attenuated inversion recovery and contralateral asymmetric pachymeningeal enhancement. Contrast-enhanced T1-weighted imaging revealed ipsilateral facial nerve enhancement.

• Investigative Magnetic Resonance Imaging
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• v.22 no.1
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• pp.56-60
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• 2018

Therapeutic hypothermia in cardiac arrest patients is associated with favorable outcomes mediated via neuroprotective mechanisms. We report a rare case of a 32-year-old male who demonstrated complete recovery of signal changes on perfusion-weighted imaging after therapeutic hypothermia due to cardiac arrest. Brain MRI with perfusion-weighted imaging, performed three days after ending the hypothermia therapy, showed a marked decrease in relative cerebral blood flow (rCBF) and delay in mean transit time (MTT) in the bilateral basal ganglia, thalami, brain stem, cerebellum, occipitoparietal cortex, and frontotemporal cortex. However, no cerebral ischemia was not noted on diffusion-weighted imaging (DWI) or fluid-attenuated inversion recovery (FLAIR) sequences. A follow-up brain MRI after one week showed complete resolution of the perfusion deficit and the patient was discharged without any neurologic sequelae. The mechanism and interpretation of the perfusion changes in cardiac arrest patients treated with therapeutic hypothermia are discussed.

• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.302-308
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• 2013

Objective : MR perfusion and single photon emission computerized tomography (SPECT) are well known imaging studies to evaluate hemodynamic change between prior to and following superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease. But their side effects and invasiveness make discomfort to patients. We evaluated the ivy sign on MR fluid attenuated inversion recovery (FLAIR) images in adult patients with moyamoya disease and compared it with result of SPECT and MR perfusion images. Methods : We enrolled twelve patients (thirteen cases) who were diagnosed with moyamoya disease and underwent STA-MCA anastomosis at our medical institution during a period ranging from September of 2010 to December of 2012. The presence of the ivy sign on MR FLAIR images was classified as Negative (0), Minimal (1), and Positive (2). Regions were classified into four territories: the anterior cerebral artery (ACA), the anterior MCA, the posterior MCA and the posterior cerebral artery. Results : Ivy signs on preoperative and postoperative MR FLAIR were improved (8 and 4 in the ACA regions, 13 and 4 in the anterior MCA regions and 19 and 9 in the posterior MCA regions). Like this result, the cerebrovascular reserve (CVR) on SPECT was significantly increased in the sum of CVR in same regions after STA-MCA anastomosis. Conclusion : After STA-MCA anastomosis, ivy signs were decreased in the cerebral hemisphere. As compared with conventional diagnostic modalities such as SPECT and MR perfusion images, the ivy sign on MR FLAIR is considered as a useful indicator in detecting brain hemodynamic changes between preoperatively and postoperatively in adult moyamoya patients.

• Journal of Korean Neurosurgical Society
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• v.30 no.10
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• pp.1182-1186
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• 2001

Objectives : MR fluid-attenuated inversion recovery(FLAIR) image uses paired long inversion time and relaxation time that nulls the signal from CSF. With nulling of the CSF long echo time readout could be used to increase T2-weighting, hence improving the conspicuousness of most tissue lesions without the deleterious effects of CSF artifact seen on T2 weighted sequence. We examed the usefulness of FALIR image in the diagnosis of mild head injury. Methods : A total of 38 patients with mild head injury were examined by FLAIR image. We compared those images with CT scan and T1, T2-weighted images. Careful observation of MR images were done by two well-trained neuroradiologists. Each image was compared for conspicuousness and detectability of traumatic lesions might have shown abnormal signal intensities. The Wilcoxon signed ranks test was used for statistical evaluation. Results : The FLAIR image was significantly more sensitive than those of other images(p<0.001). T2 FFE(Fast Field Echo) image was more useful for detection of small petechial hemorrhages. Conclusion : FLAIR image is considered to be more sensitive than those of conventional MR images in the evaluation of mild head injuries.

• Clinical and Experimental Pediatrics
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• v.55 no.9
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• pp.354-357
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• 2012

Behçet disease (BD) is rare in childhood. We report a 9-year-old boy with neuro-Behçet disease who presented diplopia and weakness on the left side after a cerebral concussion. Brain magnetic resonance imaging (MRI) revealed hyperintensity of the right mesodiencephalic junction on T2-weighted and fluid attenuated inversion recovery images. Prednisolone administration resulted in complete remission and normalization of abnormal MRI finding. Brain MRI is a useful diagnostic tool when the neurological sign is the first symptom of subclinical BD.

• Investigative Magnetic Resonance Imaging
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• v.21 no.4
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• pp.264-268
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• 2017

South Korea has the highest reported suicide rate among all countries belonging to the Organization for Economic Cooperation and Development. Nitrogen is a colorless, odorless and nontoxic gas. Nitrogen gas has, however, been recently used as a method of attempted suicide, its nontoxity notwithstanding. We herein report on an unusual case involving a 30-year-old male who presented with symptoms after a suicide attempt by nitrogen inhalation. Diffusion-weighted imaging of his brain was showed curvilinear high signal intensity in the bilateral frontal and right occipital cortices, with subtle low apparent diffusion coefficient value. In addition, T2-weighted images and fluid attenuated inversion recovery images revealed subtle high signal intensity in the bilateral frontal cortices, basal ganglia and occipital cortices with contrast enhancement.

• Journal of Korean Neurosurgical Society
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• v.54 no.2
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• pp.139-141
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• 2013

Presented here is a 36-year-old male with arterial hypertension who developed brainstem edema and intracranial hemorrhage. Magnetic resonance scan revealed diffuse brainstem hyperintensity in T2-weighted and fluid-attenuated inversion-recovery images, with an increase in apparent diffusion coefficient values. After a reduction in blood pressure, rapid resolution of the brainstem edema was observed on follow-up. The patient's condition was thus interpreted as hypertensive brainstem encephalopathy. While many consider this a vasogenic phenomenon, induced by sudden, severe hypertension, the precise mechanism remains unclear. Prompt recognition and aggressive antihypertensive treatment in such patients are essential to prevent permanent or life-threatening neurologic injury.

• Investigative Magnetic Resonance Imaging
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• v.25 no.4
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• pp.281-292
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• 2021

Cranial-nerve disorders can be caused by a wide spectrum of diseases, including congenital, inflammatory, and tumorous diseases, and are often encountered in practice. However, the imaging of cranial-nerve disorders is challenging, and understanding the anatomical differences of each region is essential for conducting the best protocols and for detecting subtle changes in cranial nerves during magnetic resonance imaging (MRI) examinations. In this review we discuss which MRI techniques are best for observing normal and pathologic appearance, according to the different regions of the cranial nerves.

• Investigative Magnetic Resonance Imaging
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• v.23 no.3
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• pp.210-219
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• 2019

Purpose: The purpose of this study was to investigate if double inversion recovery (DIR) imaging can have a role in the evaluation of brain ischemia, compared with diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) imaging. Materials and Methods: Sixty-seven patients within 48 hours of onset, underwent MRI scans with FLAIR, DWI with b-value of 0 (B0) and $1000s/mm^2$, and DIR sequences. Patients were categorized into four groups: within three hours, three to six hours, six to 24 hours, and 24 to 48 hours after onset. Lesion-to-normal ratio (LNR) value was calculated and compared among all sequences within each group, by the Friedman test and conducted among all groups, for each sequence by the Kruskal-Wallis test. In qualitative assessment, signal intensity changes of DIR, B0, and FLAIR based on similarity with DWI and image quality of each sequence, were graded on a 3-point scale, respectively. Scores for detectability of lesions were compared by the McNemar's test. Results: LNR values from DWI were higher than DIR, but not statistically significant in all groups (P > 0.05). LNR values of DIR were significantly higher than FLAIR within 24 hours of onset (P < 0.05). LNR values were significantly different between, before, and after six hours onset time for DIR (P = 0.016), B0 (P = 0.008), and FLAIR (P = 0.018) but not for DWI (P = 0.051). Qualitative analysis demonstrated that detectability of DIR was higher, compared to that of FLAIR within 4.5 hours and six hours of onset (P < 0.05). Also, the DWI quality score was lower than that of DIR, particularly relative to infratentorial lesions. Conclusion: DIR provides higher detectability of hyperacute brain ischemia than B0 and FLAIR, and does not suffer from susceptibility artifact, unlike DWI. So, DIR can be used to replace evaluation of the FLAIR-DWI mismatch.

• Clinical and Experimental Pediatrics
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• v.54 no.10
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• pp.422-424
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• 2011

Acute disseminated encephalomyelitis (ADEM) is an inflammatory demyelinating disease of the central nervous system that typically follows an infection or vaccination and has a favorable long-term prognosis. We describe the first reported case of ADEM after vaccination against novel influenza A (H1N1). A previously healthy 34-month-old boy who developed ADEM presented with a seizure and left-sided weakness 5 days after vaccination against novel influenza A (H1N1). Cerebrospinal fluid examination revealed elevated cell counts. T2-weighted images and fluid-attenuated inversion recovery images revealed multiple patchy hyperintense lesions in the frontal and parietal subcortical white matter and the left thalamus. After the administration of intravenous corticosteroid, the patient's clinical symptoms improved and he recovered completely without neurologic sequelae.