• Investigative Magnetic Resonance Imaging
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• v.8 no.1
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• pp.17-23
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• 2004

Purpose : To evaluate changes in total cerebral blood flow (tCBF) with aging, parenchymal volume changes and vascular abnormalities, using 2 dimensional (D) phase-contrast magnetic resonance imaging (PC MRI). Materials and Methods : Routine brain MRI including T2 weighted image, time-of-flight (TOF) MR Angiography (MRA) and 2D PC MRI were performed in 73 individuals, including 12 volunteers. Normal subjects (12 volunteers, and 21 individuals with normal MRI and normal MRA) were classified into groups according to age (18-29, 30-49 and 50-66 years). For the group with abnormalities in brain MRIs, cerebral parenchymal volume changes were scored according to the T2 weighted images, and atherosclerotic changes were scored according to the MRA findings. Abnormal groups were classified into 4 groups: (i) mild reduction in volume, (ii) marked reduction in volume by parenchymal volume and atherosclerotic changes, and (iii) increased volume and (iv) Moya-moya disease. Volumetric flow was measured at the internal carotid artery (ICA) and vertebral artery bilaterally using the velocity-flow diagrams from PC MRI, and combined 4 vessel flows and tCBF were compared among all the groups. Results : The age-specific distribution of tCBFs in normal subjects were as follows: $12.0{\pm}2.1ml/sec$ in 18-29 years group, $11.8{\pm}1.9ml/sec$ in 30-49 years group, $10.9{\pm}2.2ml/sec$ in 50-66 years group. The distribution of tCBFs in the different subsets of the abnormal population were as follows: $9.5{\pm}2.5ml/sec$ in the group with mild reduction in volume, $7.6{\pm}2.0ml/sec$ in the group with marked reduction in volume, and $7.3{\pm}1.2ml/sec$ and $7.0{\pm}1.1ml/sec$ in the increased parenchymal volume and Moya-moya disease groups respectively. Conclusion : Total cerebral blood flow decreases with increasing age with a concomitant reduction in parenchymal volumes and increasing atherosclerotic changes. It is also reduced in the presence of increased parenchymal volume and Moya-moya disease.2D PC MRI can be used as a tool to evaluate tCBF with aging and in the presence of various conditions that can affect parenchymal volume and cerebral vasculature.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.441-446
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• 2009

Background: Side clamping of ascending aorta during proximal graft anastomosis in coronary bypassing surgery in-creases the risk of direct aortic injury as well as embolization of intimal atheroma. Heartstring proximal sealing system (Guidant Corporation, Santa Clara, Calif), developed to avoid aortic side clamping, may minimize risks of such complications. The aim of the current study is to compare the surgical outcomes of the two proximal anastomosis techniquesi.e., Heartstring system versus aortic side clamping in off pump coronary bypassing' surgery (OPCAB). Material and Method: From January 2003 to August 2008, 499 patients underwent OPCAB. Of them, proximal graft anastomosis was performed using Heartstring system in 182 patients (Group I) and conventional manual anastomosis in 317 patients (Group II). The two groups were compared for postoperative major complications and mortality. Result: Two groups showed similar characteristics in terms of preoperative demographic data, left ventricular ejection fraction, renal function and history of diabetes, hypertension and smoking. Although there was no inter-group difference in the history of cerebral ischemia (p=0.48), preoperative brain magnetic resonance angiography revealed greater incidence of severe carotid artery stenosis (>75% of lumen) in the Group I than in the. Group II (44.5% in the Group I and 30.0% in the Group II, p=0.003). There were no inter-group differences in postoperative mortality (p=0.40) and complications (p=0.47) including neurologic events (3 in the Group land 2 in the Group II, p=0.258). Whereas neurologic events all comprised transient ischemic attacks in the Group I, they comprised multiple embolic strokes in the Group II. One patient in the Group II experienced aortic dissection during proximal anastomosis which resulted in ascending aortic replacement. Conclusion: Although proximal anastomosis using Heartstring system did not show statistically significant benefit over aortic side clamping, the. absence of embolic stroke maybe a definite benefit which may be better defined through further studies over a larger cohort.

• Radiation Oncology Journal
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• v.15 no.3
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• pp.215-224
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• 1997

Purpose : Stereotactic radiosurgery with external beam irradiation successfully obliterates carefully selected intracranial arteriovenous malformation (AVM) . We Present clinical and radiological long term results after treatment with a single high dose irradiation using a linear accelerator. Materials and Methods : Rrom January 1991 to June 1994, fifteen patients with intracranial AVM were treated in our hospital with the stereotactic radiosurgery using a linear accelerator. The radiation was delivered using a 6 MV linear accelerator. The prescribed doses at the isocenter varied from 1800 to 2500cGy (median : 2000cGy) and were given as a sin91e fraction. The radiation doses at the periphery of the lesion typically corresponded to the 80-90% isodose line. In 14 patients, complete clinical and/or radiological follow-up examination were available. Results : Angiography was available in 13 patients with a follow-up Period from 18 months to 27 months. Of 13 patients, the overall complete obliteration rate was 92.3% (12 patients). This incidence did not correlate with lesion size. Seizure, headache and progressive neurologic deficit were complete recovered. One Patient experienced hemorrhage at 2 months after treatment. One patient developed radiation induced brain edema in the white matter surrounding nidus at 16 months after treatment and showed complete resolution of the edema in MR image obtained at 27 months after treatment. After a follow-up period of up to 6 years, no radiation induced severe late complications occurred. Conclusion : We conclude that stereotactic radiosurgery using a linear accelerator is an effective and safe therapy for symptomatic and surgically inaccessible intracranial AVMs and the results compare favorably to the more expensive and elaborate systems that are currently available for stereotactic radiosurgery.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.17-24
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• 2014

Purpose : To determine whether high-resolution contrast-enhanced three dimensional imaging with spoiled gradient-recalled sequence (HR-CE 3D-SPGR) plays a meaningful role in the assessment of intracranial vertebral artery (ICVA) and posterior inferior cerebellar artery (PICA) in lateral medullary infarction (LMI). Materials and Methods: Twenty-five patients confirmed with LMI were retrospectively enrolled with approval by the IRB of our institute, and 3T MRI with HR-CE 3D-SPGR and contrast-enhanced magnetic resonance angiography (CE-MRA) were performed. Two radiologists who were blinded to clinical information and other brain MR images including diffusion weighted image independently evaluated arterial lesions in ICVA and PICA. The demographic characteristics, the area of LMI and cerebellar involvement were analyzed and compared between patients with arterial lesion in ICVA only and patients with arterial lesions in both ICVA and PICA on HR-CE 3D-SPGR. Results: Twenty-two of twenty-five LMI patients had arterial lesions in ICVA or PICA on HR-CE 3D SPGR. However twelve arterial lesions in PICA were not shown on CE-MRA. Concurrent cerebellar involvement appeared more in LMI patients with arterial lesion in ICVA and PICA than those with arterial lesion in ICVA alone (p = 0.069). Conclusion: HR-CE 3D-SPGR can help evaluate arterial lesions in ICVA and PICA for LMI patients.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.223-230
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• 2010

The purpose of this study was to utilize Magnetic Resonance Imaging (MRI) and Magnetic Resonance Angiography (MRA) to analyze intracerebral regional distributions (hot spot) of ischemic cerebrovascular diseases which were characterized by stenosis and occlusion cerebral vasculature, except for cerebrovascular diseases induced by rupture of cerebral vasculature in terms of Korean people's cerebrovascular diseases, so that it could apply the findings of analysis to clinical practices. This study focused only on analyzing intracerebral regional distributions of ischemic cerebrovascular diseases that are characterized by stenosis and occlusion cerebral vasculature, because there are different etiologic mechanisms of ischemic cerebrovascular diseases like hemorrhagic cerebrovascular diseases (caused by rupture of cerebral vasculature) and cerebral infarction (induced by atheromatous arteriosclerosis). As a result, this study could come to the following findings of analysis: 1. According to sex ratio analysis, it was found that male group comprised larger portion of total 626 subjects in this study than female one (55.0% > 45.0%). 2. According to analysis on actual intracerebral regional distributions of ischemic cerebrovascular diseases, it was found that most subjects (37.5 %) were attacked by such diseases on the right side of cerebral vasculature, which was followed by left side of cerebral vasculature (35.1%) and bilateral cerebral vasculature (27.3%) respectively. 3. According to analysis on actual intracerebral regional distributions of ischemic cerebrovascular diseases, it was found that internal carotid artery (ICA) comprised the largest portion (38.9%) of those distributions, which was followed by middle cerebral artery (MCA, 35.7%), posterior cerebral artery (PCA, 13.4%), anterior cerebral artery (ACA, 6.0%) and vertebral artery (VA, 3.3%) respectively. 4. It was found that there was no subject attacked by any disease on A-com region, and there was only one male subject attacked by cerebrovascular diseases on P-com region. 5. It was found that female group was more susceptible to the attack of cerebrovascular diseases on MCA region than male one (54.6% > 42.2%), which means significant differences depending upon sex on statistical basis ($x^2$ = 9.64, p < .01). 6. It was found that male group was more susceptible to the attack of cerebrovascular diseases on ICA region (56.4% > 46.8%), which means significant differences depending upon sex on statistical basis ($x^2$ = 5.71, p < .05). 7. Moreover, it was also found that male group was more susceptible to the attack of cerebrovascular diseases on BA region (2.3% > 0.4%), which means significant differences depending upon sex on statistical basis ($x^2$ = 4.25, p < .05). 8. However, it was found that there was not any significant difference in intracerebral vasculature-specific distributions of cerebrovascular diseases depending on age of subjects, and stenosis comprised larger portion of cerebrovascular diseases than occlusion.