Biomedical subjects

Si Yeon Kim

Publications and source records attributed to Si Yeon Kim.

5 recordsLinked to original sources

PubMed2004

Diffusion tensor MR imaging visualizes the altered hemispheric fiber connection in callosal dysgenesis.

We report three cases of callosal dysgenesis that were evaluated by diffusion tensor imaging and fiber tractography. In partial agenesis of corpus callosum, fiber tracts from all regions of brain converged to a partially developed small genu portion and connected to the contralateral side. In complete callosal agenesis, fibers from the hemispheres failed to cross the midline and formed thick bundles running anteroposteriorly (eg, Probst bundle). The thickness of the anterior commissure was enlarged or smaller than normal brain, and other white matter tracts were not markedly different from normal brain tissue.

Abnormalities, Multiple↗

PubMed2004

Reperfusion cellular injury in an animal model of transient ischemia.

BACKGROUND AND PURPOSE: Early thrombolytic therapy is encouraged in hyperacute stroke, although this might result in delayed reperfusion injury. Our purpose was to investigate the serial changes in cerebral perfusion following transient ischemia by means of MR imaging and to correlate them with the histologic findings obtained by using the TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay. METHODS: One-hour transient occlusion of the middle cerebral artery was produced in 10 cats. Serial perfusion-weighted MR imaging was performed for 3 days after reperfusion. The reperfusion characteristics in each region of the brain were classified into four groups according to the serial perfusion MR imaging status: normal perfusion (N), continuous hyperperfusion (I), early hyperperfusion and gradual decrease (II), and persistent hypoperfusion (III). After the last imaging session, a specimen was obtained, and TUNEL staining was performed. TUNEL-positive cells were counted under a high-power-field (HPF) light microscope (x200). The degree of TUNEL positivity was compared among the four reperfusion groups classified on the basis of serial perfusion-weighted imaging findings. RESULTS: Group N had 16.8 +/- 5.1 TUNEL-positive cells per HPF. Groups I and II had a statistically significant increase in TUNEL positivity (39.5 +/- 13.4 and 43.6 +/- 16.7 cells per HPF; P < .01, one-way analysis of variance), whereas group III had a statistically insignificant increase in TUNEL positivity (23.3 +/- 6.9 cells per HPF). CONCLUSION: Reperfusion followed by hyperperfusion induced cellular damage, although the initial MR imaging findings were normal. The inclusion of anti-reperfusion injury therapy should be considered in thrombolytic treatment.

Animals↗

PubMed2003

Homonymous hemianopia after embolization of an aneurysm-associated AVM supplied by the anterior choroidal artery.

The primary objective for the treatment of arteriovenous malformations (AVM) of the brain is to reduce the risk of hemorrhage. The risk of hemorrhage is known to increase with the presence of an aneurysm associated with AVM. The purpose of this report is to describe the development of visual complications after the embolization of a hemorrhagic anterior choroidal artery feeding AVM with an associated aneurysm and to describe the possible causes.

Adult↗

PubMed2003

Diffusion tensor MRI and fiber tractography of cerebellar atrophy in phenytoin users.

PURPOSE: The usefulness of diffusion tensor magnetic resonance imaging (DT-MRI) is still in debate, and the development of clinically feasible scan protocol is encouraged. The purpose of this study was to investigate the afferent fiber system to the cerebellum in patients with phenytoin (PHT)-induced cerebellar atrophy in comparison with cerebellar atrophy of other etiologies by using DT-MRI. METHODS: Thirteen patients (M/F ratio, 7:6; mean age, 42.5 years) and age-matched normal controls (n = 8) participated in this study. The patient group consisted of epilepsy patients who had received PHT therapy (n = 9) and clinically diagnosed as having olivopontocerebellar atrophy (OPCA; n = 4). DT-MRI was performed by using diffusion weighting of b = 600 s/mm2, and fractional anisotropy (FA) and color-coded vector maps were generated. FA of the middle cerebellar peduncle (MCP), the cerebellum, and transverse pontine fibers (TPF) was measured and compared between PHT and OPCA patients. RESULTS: Normal subjects showed FA values of 0.81 +/- 0.07 in MCP, 0.69 +/- 0.04 in TPF, and PHT users showed FA values of 0.84 +/- 0.09 in MCP, 0.72 +/- 0.08 in TPF, and 0.21 +/- 0.04 in cerebellum. OPCA patients showed FA values of 0.39 +/- 0.11 in MCP, 0.46 +/- 0.12 in TPF, and 0.22 +/- 0.07 in cerebellum. PHT users showed a statistically significant reduction of FA only in cerebellum, whereas OPCA demonstrated significant decrease of FA in MCP, TPF, and cerebellum (one-way analysis of variance, p < 0.01). Three-dimensional reconstruction of fiber tracts demonstrated decreased volume and altered fiber integrity within the peduncles and transverse pontine fibers in the OPCA group, whereas fiber course patterns in PHT users were similar to those in controls. CONCLUSIONS: PHT users showed normal orientation and anisotropy of MCP and TPF, whereas OPCA demonstrated impaired values, suggesting that PHT directly affects the cerebellum. DT-MRI can demonstrate detailed fiber configurations in degenerative diseases of brainstem and cerebellum and provides insight into the pathomechanisms of cerebellar atrophy.

Adult↗

PubMedDate not supplied

Unruptured aneurysms with cranial nerve symptoms: efficacy of endosaccular Guglielmi detachable coil treatment.

OBJECTIVE: To evaluate the efficacy of endosaccular Guglielmi detachable coil (GDC) treatment of unruptured aneurysms causing cranial nerve (CN) symptoms. MATERIALS AND METHODS: Among a database of 218 patients whose aneurysms were treated using GDC, seven patients met the criteria for unruptured aneurysms presenting with symptoms and signs of CN palsy. Changes in CN symptoms before and after GDC treatment were reviewed. RESULTS: Aneurysms were located in the internal carotid-posterior communicating artery (n=3), the basilar bifurcation (n=1) and the cavernous internal carotid artery (n=3). CN symptoms included ptosis (n=6), mydriasis (n=2), and extraocular muscle (EOM) disorder (CN III: n=4; CN VI: n=3). Overall, improvement or resolution of CN symptoms after treatment was noted in five patients. CN symptoms in cases involving small (</= =10 mm) and intradural aneurysms tended to respond better to GDC treatment. Ptosis was the initial symptom to show improvement, while EOM dysfunction responded least favourably. CONCLUSION: GDC coil packing appears to be an appropriate treatment method for the relief of CN symptoms associated with intracranial aneurysms.

Cranial Nerve Diseases↗