• Journal of Chest Surgery
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• v.13 no.3
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• pp.274-279
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• 1980

A 21 years old male student was admitted because of mediastinal mass that was noticed in routine physical examination. He complained progressive hoarseness, mild dysphagia, and anterior chest pain on deep respiration. This mediastinal mass was diagnosed as aortic aneurysm involving ascending, transverse, and descending thoracic aorta with aid of aortogram. Total prosthetic replacement of aneurysm was performed successfully using extracorporeal circulation and hypothermia. For myocardial protection during aortic cross clamping, cardioplegic solution was used and topical myocardial cooling was also adapted For simplicity of cardiopulmonary bypass, Y-shaped connectors took cerebral perfusion catheters to the main perfusion line beyond the arterial pump. Total bypass time was 219 minutes, and aortic cross clamp time was 104 minutes. Recovery was uneventful except respiratory insufficiency for first 4 days. Isotope aortogram checked on post operative 30th day showed normal aortic configuration. He was discharged on post operative 35th day. A follow-up chest X-ray study 5 months later showed nearly normal anatomy.

• Journal of Chest Surgery
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• v.33 no.8
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• pp.676-680
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• 2000

To minimize the period of brain ischemia and the potential for neurologic damage during aortic arch replacement, we used the arch-first technique. First case was a 28-year-old female with extensive aneurysm involving ascending, arch and descending thoracic aorta. Exposure was obtained via a bilateral via a bilateral thoracotomy (clamshell incision) in the anterior 4th right and 3rd left intercostal space with oblique sternotomy. To prepare for arch perfusion, the side-arm graft(10mm) was anastomosed to the aortic graft, opposite the site of the planned anastomosis to the arch vessels. After completing the arch anastomosis under total circulatory arrest(37min) and retrograde cerebral perfusion(12min), aortic graft was clamped on either side and the arch was perfused via side-arm graft for 36min. When distal aortic anastomosis was finished, distal clamp of aortic graft was released and arch vessels were perfused via common femoral artery, and the proximal aortic anastomosis was accomplished. The patient was discharged with no event. Second case was a 48-year-old male with extensive aneurysm involving ascending, arch, and aortic regurgitaiton(grade III/IV). This case was also done using the clamshell incision. Aortic valve replacement was done by valved-conduit(Vascutek 30mm), both coronary artery anastomosis using Cabrol's procedure. Last operation procedure was the same as the 1st case.

• 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 Chest Surgery
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• v.30 no.7
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• pp.686-692
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• 1997

This study represents an attempt to present an analysis of early surgical results in 15 cases of aortic surgery conducted at Chonnam University Hospital between February 1994 to August 1995. The subject, 9 males and 6 females, ranged in age from 32 to 73 years with a mean age of 55.07$\pm$ 1176 years. The patients were treated for dissecting aortic aneurysm in nine, atherosclerotic aneurysm in 4, and traumatic aortic aneurysm in two. There were 9 cases of median stemotomy, 4 cases of posterolateral thoracotomy, and 2 cases of thoracoabdominal incision. Graft replacement of ascending aorta andfor partial or total aortic arch were performed in 9 patients, descending aorta andfor t oracoabdominal aorta in 3 and total aorta in 1, Two traumatic aortic aneurysms were closed directly. Associate procedures were resuspension of aortic valve in three patients and elephant trunk procedure, coronary reimplantation and aortic valve replacement in one patient. Nine patients underwent operation for ascending aorta andfor aortic arch with retrograde cerebral perfusion during deep hypothermia and circulatory arrest. Perfusion pressure was maintained below 25 mmHg and the mean duration of circulatory arrest was 56.67 $\pm$ 29.25 minutes. Three patients underwent graft replacement of desending thoracic and thoracoabdominal aorta during deep hypothermia and circulatory arrest. Three patients died of traumatic bile peritonitis, multioragn failure, and rupture of residual dissecting aortic aneurysm by malignant hypertension. Postoperative complications included reoperation for bleeding in 4 patients, temporary confusion in 3, pulmonary complication in 3, and pericardial effusion in .

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.626-637
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• 2021

Purpose To explore cerebrovascular reservoir (CVR) and arterial transit time (ATT) changes using acetazolamide-challenged multi-phase arterial spin labeling (MP-ASL) perfusion-weighted MRI in chronic cerebrovascular steno-occlusive disease. Materials and Methods This retrospective study enrolled patients with chronic steno-occlusion who underwent acetazolamide-challenged MP-ASL between June 2019 and October 2020. Cerebral blood flow, CVR, basal ATT, and ATT changes associated with severe stenosis, total occlusion, and chronic infarction lesions were compared. Results There were 32 patients (5 with bilateral steno-occlusion) in our study sample. The CVR was significantly reduced during total occlusion compared with severe stenosis (26.2% ± 28.8% vs. 41.4% ± 34.1%, respectively, p = 0.004). The ATT changes were not significantly different (p = 0.717). The CVR was marginally lower in patients with chronic infarction (29.6% ± 39.1% vs. 38.9% ± 28.7%, respectively, p = 0.076). However, the ATT was less shortened in patients with chronic infarction (-54 ± 135 vs. -117 ± 128 ms, respectively, p = 0.013). Conclusion Acetazolamide-challenged MP-ASL provides an MRI-based CVR evaluation tool for chronic steno-occlusive disease.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.276-286
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• 2013

SVD-based deconvolution algorithm has been known as the most effective technique for CT perfusion image analysis. In this algorithm, in order to reduce noise effects, SVD coefficients smaller than a certain threshold are removed. As the truncation threshold, either a fixed value or a variable threshold yielding a predetermined OI (oscillation index) is frequently employed. Each of these two thresholding methods has an advantage to the other either in accuracy or efficiency. In this paper, we propose a Monte Carlo simulation method to evaluate the accuracy of the two methods. An extension of the proposed method is presented as well to measure the effects of image smoothing on the accuracy of the thresholding methods. In this paper, after the simulation method is described, experimental results are presented using both simulated data and real CT images.

• Journal of Korean Neurosurgical Society
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• v.47 no.3
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• pp.203-209
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• 2010

Objective : The purpose of study was to evaluate the feasibility of brain magnetic resonance (MR) images of the rat obtained using a 1.5T MR machine in several blood-brain barrier (BBB) experiments. Methods : Male Sprague-Dawley rats were used. MR images were obtained using a clinical 1.5T MR machine. A microcatheter was introduced via the femoral artery to the carotid artery. Normal saline (group 1, n = 4), clotted autologous blood (group 2, n = 4), triolein emulsion (group 3, n = 4), and oleic acid emulsion (group 4, n = 4) were infused into the carotid artery through a microcatheter. Conventional and diffusion-weighted images, the apparent coefficient map, perfusion-weighted images, and contrast-enhanced MR images were obtained. Brain tissue was obtained and triphenyltetrazolium chloride (TTC) staining was performed in group 2. Fluorescein isothiocyanate (FITC)-labeled dextran images and endothelial barrier antigen (EBA) studies were performed in group 4. Results : The MR images in group 1 were of good quality. The MR images in group 2 revealed typical findings of acute cerebral infarction. Perfusion defects were noted on the perfusion-weighted images. The MR images in group 3 showed vasogenic edema and contrast enhancement, representing vascular damage. The rats in group 4 had vasogenic edema on the MR images and leakage of dextran on the FITC-labeled dextran image, representing increased vascular permeability. The immune reaction was decreased on the EBA study. Conclusion : Clinical 1.5T MR images using a rat depicted many informative results in the present study. These results can be used in further researches of the BBB using combined clinical MR machines and immunohistochemical examinations.

• Progress in Medical Physics
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• v.18 no.1
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• pp.35-41
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• 2007

In this work practical considerations of a pulsed arterial spin labeling MRI are presented to reliable multi-slice perfusion measurements In the human brain. Three parameters were considered in this study. First, In order to improve slice profile and Inversion efficiency of a labeling pulse a high power Inversion pulse of adiabatic hyperbolic secant was designed. A $900^{\circ}$ rotation of the flip angle was provided to make a good slice profile and excellent Inversion efficiency. Second, to minimize contributions of a residual magnetization be4ween Interleaved scans of control and labeling we tested three different conditions which were applied 1) only saturation pulses, 2) only spotter gradients, and 3) combinations of saturation pulses and spotter gradients Applications of bo4h saturation pulses and spoiler gradients minimized the residual magnetization. Finally, to find a minimum gap between a tagged plane and an imaging plane we tested signal changes of the subtracted image between control and labeled Images with varying the gap. The optimum gap was about 20mm. In conclusion, In order to obtain high quality of perfusion Images In human brain It Is Important to use optimum parameters. Before routinely using In clinical studios, we recommend to make optimizations of sequence parameters.

• Investigative Magnetic Resonance Imaging
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• v.21 no.1
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• pp.9-19
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• 2017

Background: Normalized cerebral blood volume (nCBV) can be measured using manual or semiautomatic segmentation method. However, the difference in diagnostic performance on brain tumor differentiation between differently measured nCBV has not been evaluated. Purpose: To compare the diagnostic performance of manually obtained nCBV to that of semiautomatically obtained nCBV on glioblastoma (GBM) and primary central nervous system lymphoma (PCNSL) differentiation. Materials and Methods: Histopathologically confirmed forty GBM and eleven PCNSL patients underwent 3T MR imaging with dynamic susceptibility contrast-enhanced perfusion MR imaging before any treatment or biopsy. Based on the contrast-enhanced T1-weighted imaging, the mean nCBV (mCBV) was measured using the manual method (manual mCBV), random regions of interest (ROIs) placement by the observer, or the semiautomatic segmentation method (semiautomatic mCBV). The volume of enhancing portion of the tumor was also measured during semiautomatic segmentation process. T-test, ROC curve analysis, Fisher's exact test and multivariate regression analysis were performed to compare the value and evaluate the diagnostic performance of each parameter. Results: GBM showed a higher enhancing volume (P = 0.0307), a higher manual mCBV (P = 0.018) and a higher semiautomatic mCBV (P = 0.0111) than that of the PCNSL. Semiautomatic mCBV had the highest value (0.815) for the area under the curve (AUC), however, the AUCs of the three parameters were not significantly different from each other. The semiautomatic mCBV was the best independent predictor for the GBM and PCNSL differential diagnosis according to the stepwise multiple regression analysis. Conclusion: We found that the semiautomatic mCBV could be a better predictor than the manual mCBV for the GBM and PCNSL differentiation. We believe that the semiautomatic segmentation method can contribute to the advancement of perfusion based brain tumor evaluation.

• Journal of Chest Surgery
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• v.40 no.1 s.270
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• pp.25-31
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• 2007

Background: Cerebral protection is one of the most important procedures during aortic arch surgery. We can minimize neurological complications through short period of total circulatory arrest and resuming of brain perfusion. We evaluated 11 patients who underwent arch replacement using antegrade brain perfusion via right axillary artery. Material and Method: Between July 2004 and July 2006, 11 patients (male 9, female 2) underwent aortic arch replacement with antegrade brain perfusion via right axillary artery. Preoperative diagnosis was listed; 5 type A aortic dissections (5/11, 45.5%), 5 aortic aneurysms (5/11, 45,5%) and 1 type A IMH (intramural hematoma, 1/11, 9%). The mean age at the time of operation was $60.3{\pm}12.8$ years. For antegrade brain perfusion, we performed right axillary artery cannulation in all patients. Retrograde brain perfusion was used briefly during total circulatory arrest. Result: The mean total circulatory arrest time was $31.1{\pm}16.9$ minutes and the mean retrograde brain perfusion time was $21{\pm}17.8$ minutes. Mean antegrade brain perfusion time was $77.9{\pm}17.5\;(43{\sim}101)$ minutes. We had neither operative mortality nor permanent neurological complications. Conclusion: By means of antegrade brain perfusion via right axillary artery, that could lead to decrease circulatory arrest time and minimize damages to severely atheromatous arch vessels, we can expect to reduce neurological complications after aortic arch replacement. Further investigation with iarge patient populations will be required.