• The Korean Journal of Nuclear Medicine
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• v.37 no.5
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• pp.288-300
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• 2003

Purpose: To obtain regional blood flow and tissue-blood partition coefficient with time-activity curves from ${H_2}^{15}O$ PET, fitting of some parameters in the Kety model is conventionally accomplished by nonlinear least squares (NLS) analysis. However, NLS requires considerable compuation time then is impractical for pixel-by-pixel analysis to generate parametric images of these parameters. In this study, we investigated several fast parameter estimation methods for the parametric image generation and compared their statistical reliability and computational efficiency. Materials and Methods: These methods included linear least squres (LLS), linear weighted least squares (LWLS), linear generalized least squares (GLS), linear generalized weighted least squares (GWLS), weighted Integration (WI), and model-based clustering method (CAKS). ${H_2}^{15}O$ dynamic brain PET with Poisson noise component was simulated using numerical Zubal brain phantom. Error and bias in the estimation of rCBF and partition coefficient, and computation time in various noise environments was estimated and compared. In audition, parametric images from ${H_2}^{15}O$ dynamic brain PET data peformed on 16 healthy volunteers under various physiological conditions was compared to examine the utility of these methods for real human data. Results: These fast algorithms produced parametric images with similar image qualify and statistical reliability. When CAKS and LLS methods were used combinedly, computation time was significantly reduced and less than 30 seconds for $128{\times}128{\times}46$ images on Pentium III processor. Conclusion: Parametric images of rCBF and partition coefficient with good statistical properties can be generated with short computation time which is acceptable in clinical situation.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.67-71
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• 2011

Purpose : To compare T2 relaxation times (T2) in the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex between 1.5T and 3.0T MR imagers. Materials and Methods : Twelve healthy volunteers underwent FLAIR and CPMG imaging perpendicular to the hippocampal body at both 3.0T and 1.5T. T2 was measured in the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex. The T2 relaxation time ratios of the cingulate cortex, insular cortex, and amygdaloid body to the hippocampal body were compared between 1.5T and 3.0T. Results : The mean T2 of the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex at 1.5T were $109.5{\pm}3.1$, $117.0{\pm}7.1$, $114.7{\pm}2.4$, and $111.3{\pm}2.4$, respectively; $99.7{\pm}3.8$, $100.7{\pm}4.3$, $97.9{\pm}3.4$, and $96.2{\pm}2.0$, respectively, at 3.0T. Percentage changes of T2 in the cingulate cortex, insular cortex, amygdaloid body, and hippocampal body at 3.0T with respect to those at 1.5T were -8.9%, -13.5%, -14.6%, and -13.5%, respectively. The mean T2 ratios of the cingulate gyrus, insular cortex, and amygdaloid body to the hippocampal body at 1.5T and 3.0T were 0.96 and 1.02 (p = 0.003); 1.02 and 1.03 (p>0.05); 0.97 and 0.98 (p>0.05), respectively. Conclusion : T2 decrease in the cingulate cortex was less than the amygdaloid body, insular cortex, and hippocampal body at 3.0T. The mean T2 ratio of the cingulate gyrus to the hippocampal body was significantly different between 1.5T and 3.0T.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.103-107
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• 1997

Purpose: To investigate the localization and functional lateralization of the supplementary motor area (SMA) in motor activation tests in comparison to that of the primary motor area. Materials and Methods: Seven healthy volunteers obtained echoplanar imaging blood oxygen level dependent technique. This study was carried on 1.5T Siemens Magnetom Vision system with the standard head coil. Parameters of EPI were followed as; TR/TE : 1.0/66.0msec, flip angle: $90^{\circ}$, field of view: $22cm{\times}22cm,{\;}matrix:{\;}128{\times}128$, slice number/slice thickness/gap: 1O/4mm/0.8mm with fat suppression technique. Motor task as finger opposition in each hand consisted of 3 sets of alternative rest and activation periods. Postprocessing were done on Stimulate 5.0 by using cross-correlation statistics. To compare the functional lateralization of the SMA in the right and left hand tests, each examination was evaluated for the percent change of signal intensity and the number of activated voxels both in the SMA and in the pri¬mary motor area. Hemispheric asymmetry was defined as difference of summation of the activted voxels between each hemisphere. Results: Percent change of signal intensity in the SMA (2.49 -3.06%) is lower than that of primary motor area(4.4 -7.23%). Percent change of signal intensity including activated voxels were observed almost equally in the right and left SMA. As for summation of activated voxels, primary motor area had significant difference between each hemisphere but not did the SMA. Conclusion: Preferred contralateral dominant hemisphere and hemispheric asymmetry were detected in the primary motor area but not in the SMA.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.109-113
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• 1997

Purpose: To evaluate the differences of functional imaging patterns between conventional spoiled gradient echo (SPGR) and echo planar imaging (EPI) methods in cerebral motor cortex activation. Materials and Methods: Functional MR imaging of cerebral motor cortex activation was examined on a 1.5T MR unit with SPGR (TRfrE/flip angle=50ms/4Oms/$30^{\circ}$, FOV=300mm, matrix $size=256{\times}256$, slice thickness=5mm) and an interleaved single shot gradient echo EPI (TRfrE/flip angle = 3000ms/40ms/$90^{\circ}$, FOV=300mm, matrix $size=128{\times}128$, slice thickness=5mm) techniques in five male healthy volunteers. A total of 160 images in one slice and 960 images in 6 slices were obtained with SPGR and EPI, respectively. A right finger movement was accomplished with a paradigm of an 8 activation/ 8 rest periods. The cross-correlation was used for a statistical mapping algorithm. We evaluated any differences of the time series and the signal intensity changes between the rest and activation periods obtained with two techniques. Also, the locations and areas of the activation sites were compared between two techniques. Results: The activation sites in the motor cortex were accurately localized with both methods. In the signal intensity changes between the rest and activation periods at the activation regions, no significant differences were found between EPI and SPGR. Signal to noise ratio (SNR) of the time series data was higher in EPI than in SPGR by two folds. Also, larger pixels were distributed over small p-values at the activation sites in EPI. Conclusions: Good quality functional MR imaging of the cerebral motor cortex activation could be obtained with both SPGR and EPI. However, EPI is preferable because it provides more precise information on hemodynamics related to neural activities than SPGR due to high sensitivity.

• Investigative Magnetic Resonance Imaging
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• v.8 no.1
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• pp.9-16
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• 2004

Purpose : The purpose of this study was to assess supplementary motor area (SMA) activation during motor, sensory, word generation, listening comprehension, and working memory tasks using functional magnetic resonance imaging (fMRI). Materials and Methods : Sixteen healthy right-handed subjects (9M, 7F) were imaged on a Siemens 1.5T scanner. Whole brain functional maps were acquired using BOLD EPI sequences in the axial plane. Each paradigm consisted of five epochs of activation vs. the control condition. The activation tasks consisted of left finger complex movement, hot sensory stimulation of the left hand, word generation, listening comprehension, and working memory. The reference function was a boxcar waveform. Activation maps were thresholded at an uncorrected p=0.0001. The thresholded activation maps were placed into MNI space and the anatomic localization of activation within the SMA was compared across tasks. Results : SMA activation was observed in 16 volunteers for the motor task, 11 for the sensory task, 15 for the word generation task, 5 for the listening comprehension task, and 15 for the working memory task. The rostral aspects of the SMA showed activity during the word generation and working memory tasks, and the caudal aspects of the SMA showed activity during the motor and sensory tasks. Right (contralateral) SMA activation was observed during the motor and sensory tasks, and left SMA activation during the word generation and memory tasks. Conclusion : Our results suggest that SMA is involved in a variety of functional tasks including motor, sensory, word generation, and working memory. The results obtained also support the notion that functionally specific subregions exist within the region classically defined as the SMA.

• Clinics in Shoulder and Elbow
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• v.10 no.1
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• pp.99-105
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• 2007

Purpose: The morphological study and dynamic stability of the ulnar nerve around the elbow joint was investigated in asymptomatic normal population using ultrasonography. The purpose of this study is to provide fundamental data for ultrasonographic diagnosis of ulnar neuropathy in cubital tunnel syndrome. Materials and Methods: Fifty cases of 25 healthy male volunteers, aged between 20 to 30 years, included in this study. High resolution 7.5 MHz linear probe was used to examine the ulnar nerve in axial and longitudinal views. In a longitudinal view, the course, position and the thickness of nerve were monitored, the diameter of ulnar nerve and dynamic stability at elbow flexion and extension were measured in an axial view at four different points; 1cm proximal to medial epicondyle, behind the medial epicondyle, entrance to Osborne ligament, and 1cm distal to Osborne ligament. Results: The short diameters of ulnar nerve at elbow extension at four anatomic points were 2.66 mm, 2.97 mm, 2.64 mm, and 2.69 mm and the long diameters were 4.61 mm, 4.56 mm, 4.36 mm, and 4.37 mm, which showed no significant change at each point. However, at elbow flexion, the short diameters were changed to 2.72 mm, 2.34 mm, 2.65 mm, and 2.41 mm and the long diameters into 4.49 mm, 5.40 mm, 4.16 mm, and 4.66 mm. At elbow flexion, significant morphologic change was observed in the medial epicondyle area, and the diameter of the ulnar nerve was shortest at the entrance of Osborne ligament both at flexion and extension. In terms of dynamic stability, nine subluxations and seven dislocations were observed. Conclusion: This study shows dynamic instability and a morphological change of long and short diameters of ulnar nerve at flexion and extension in a normal person, which should be considered in the ultrasonographic diagnosis of ulnar neuropathy.

• Clinical and Experimental Pediatrics
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• v.52 no.9
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• pp.1015-1020
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• 2009

Purpose:The aim of this study is to explore the effect of the Toll-like receptor 9 (TLR9) expressed in plasmacytoid dendritic cells (pDCs) that respond to antigen to Th2 immune deviation in allergic patients. Methods:Subjects consisted of 19 allergic patients and 17 healthy volunteers. Skin prick tests and nasal provocation tests were performed for the two groups. Peripheral blood mononuclear cells (PBMCs) were collected from subjects and analyzed for the Lineage Cocktail (CD3, CD14, CD16, CD19, CD20, CD56) (-), HLA-DR (+), and CD123 (+) using flow cytometry. In addition, we analyzed TLR9 mRNA by reverse transcriptase-polymerase chain reaction. The level of $interferon-{\alpha}$ ($IFN-{\alpha}$) of the PBMCs following stimulation with the TLR9 ligand CpG-ODN 2216 was also evaluated. Results:Analyses of CD123 (+) revealed a nearly similar distribution for the classical pDC markers in the allergic group ($0.1%{\pm}0.04%$) and in the controls ($0.25%{\pm}0.23%$). The mRNA levels of TLR9 on PBMCs were not different between the allergic group and the controls ($1.29{\pm}0.41$ vs. $1.25{\pm}0.23$, respectively). Additionally, the level of $IFN-{\alpha}$ in PBMCs exposed to stimuli of the TLR9 ligand CpG-ODN 2216 was not significantly different between the two groups ($911{\pm}829$ vs. $1,095{\pm}888pg/mL$, respectively). Conclusion:We found no evidence that TLR9-dependent immune responses in human pDCs are associated with allergic status.

• The Journal of Korean Society for Radiation Therapy
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• v.19 no.2
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• pp.83-90
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• 2007

Purpose: In this study, it was investigated whether commercially produced beer is able to prevent a lymphocyte from radiation induced apoptosis. Materials and Methods: Whole blood samples were acquired from 5 healthy volunteers (male, 26$\sim$38 years old) and the lymphocyte were isolated by density gradient centrifugation. Radiation induced apoptosis of the lymphocyte were investigated by 0.5 Gy, 1.0 Gy, 2.0 Gy, 3.0 Gy to 5.0 Gy irradiation. In some experiments, the donor drunk beer and then blood samples were collected. In other experiments, melatonin or glycine betain was added to lymphocyte culture medium. Treated or untreated lymphocytes were cultured for 60 hours and radiation induced apoptosis of the lymphocyte was analyzed by annexin-V staining through flow cytometery. Results: Relative radiation induced apoptosis ratio of the untreated lymphocytes is 1.22$\pm$1.1, 1.22$\pm$1.1, 1.38$\pm$1.0, 1.47$\pm$1.1, 1.50$\pm$1.2 by radiation dose of 0.5 Gy, 1.0 Gy, 2.0 Gy, 3.0 Gy and 5.0 Gy respectively. Relative radiation induced apoptosis ratio of lymphocytes is isolated from beer drunken donors is 0.97$\pm$1.0, 0.99$\pm$1.0, 1.11$\pm$0.9, 1.29$\pm$1.1, 1.15$\pm$1.1 by radiation doses respectively which are reduced 21.5% compared with untreated lymphocyte. Relative radiation induced apoptosis ratio of the lymphocytes is isolated from non-alcohol beer drunken donors is 1.22$\pm$1.1, 1.17$\pm$1.1, 1.13$\pm$1.3, 1.38$\pm$1.2, 1.32$\pm$1.1 by radiation dose of 0.5 Gy, 1.0 Gy, 2.0 Gy, 3.0 Gy and 5.0 Gy respectively which are reduced 10.8% compared with the untreated lymphocyte. Conclusion: As a result, it is suggested that beer may protect the lymphocyte from radiation damage and inhibit apoptosis.

• Journal of Nutrition and Health
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• v.42 no.6
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• pp.516-522
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• 2009

In this study, the effects of a mixture consisting of vitamin E, vitamin C, pycnogenol and evening primrose oil (mixture LGNC-5) on ultraviolet light (UV) induced pigmentation and wrinkle reductions of normal healthy volunteers were studied. In a double-blind placebo-controlled study, each of 54 subjects took daily either 4 capsules of the mixture LGNC-5 (Group ABC; 282.5 mg/capsule) or placebo (Group Ganada). We irradiated 2.5 MED UV on the upper arms and measured the whitening effect by colorimeter-based L value. The level of wrinkle reduction was determined by image analysis using skin replica around the crow' feet, and the level of serum vitamin E was determined at baseline and 12 weeks. After 12-week oral administration, the treated group showed a significant reduction in skin pigmentation and wrinkles compared with the placebo group (p = 0.011 and p = 0.000005, respectively). Also, the level of serum vitamin E was significantly increased in the treated group after 12-week oral adminstration of the mixture compared with that in the placebo group (p = 0.0001). In conclusion, 12-week oral administration of LGNC-5 as a dietary supplement could be effective to reduce both UV induced pigmentation and skin wrinkle without side effects.

• Radiation Oncology Journal
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• v.21 no.1
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• pp.75-81
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• 2003

Purpose : This study quantitatively evaluated the apoptosis In human peripheral blood lymphocytes using flow cytometry, and investigated the possibility of using this method, with a small amount of blood, and the time and dose dependence of radiation-induced apoptosls. Materials and Methods : Peripheral blood lymphocyes were isolated from the heparinized venous blood of 11 healthy volunteers, 8 men and 3 women, with each 10 ml of blood being divided Into IS samples. The blood lymphocytes were Irradiated using a linear accelerator at a dose rate of 2.4 Gy/min, to deliver doses of 0.5, 1, 2 and S Gy. The control samples, and Irradiated cells, were maintained in culture medium for 24, 48 and 72 hours fellowing the Irradiation. The number of apoptotic cells after the in vitro X-irradiation was measured by flow cytometry after Incubation periods of 24, 48 and 72 hours. We also observed the apoptotic cells using a DNA fragmentation assay and electron microscopy. Results : The rate oi spontaneous apoptosis increased in relation to the time interval following irradiation (1.761 ${\pm}$0.161, 3.563${\pm}$0.554, 11.098${\pm}$2.849, at 24, 48, and 72 hours). The apoptotli cells also increased In the samples irradiated with 0.5, 1, 2 and 5 Gy, In a radiation dose and time interval after Irradiation manner, with the apoptosls being too great at 72 hours after Irradiation. The dose-response curves were characterized by an Initial steep Increase In the number of apoptotic cells for Irradiation doses below 2 Gy, with a flattening of the curves as the dose approached towards 5 Gy. Conclusion :The flow cytometric assay technique yielded adequate data, and required less than 1 mL of blood. The time and dose dependence of the radiation-induced apoptosis, was also shown. It is suggested that the adequate time Interval required for the evaluation of apoptosis would be 24 to 48 hours after blood sampling.