Manganese-Enhanced Magnetic Resonance Imaging of the Spinal Cord in Rats

Manganese-enhanced magnetic resonance imaging (MEMRI) offers a novel neuroimaging method in visualizing the activity patterns of neural circuits. MEMRI is using the divalent manganese ion, which has been used as a cellular contrast agent. The present study was conducted to determine the contrast-enhancing effects of manganese ion administered into the spinal cord of rats. Manganese ion was administered into the spinal cord by lumbar puncture. Ex vivo magnetic resonance images were obtained at 6, 12, 24, and 48 hours after manganese ion injection. Although the highly contrasted images were not observed 6 or 12 hr after manganese injection, the distinctive manganese-enhanced images began to appear at 24 hours after manganese ion injection. These results suggest that the gray matter is the foci of intense paramagnetic signals and MEMRI may provide an effective technique to visualize the activity-dependent patterns in the spinal cord.

Observations of Oxygen Administration Effects on Visuospatial Cognitive Performance using Time Course Data Analysis of fMRI

PURPOSE: This study attempted to investigate the effects of supply of highly concentrated (30%) oxygen on human ability of visuospatial cognition using time course data analysis of functional Magnetic Resonance Imaging (fMRI). MATERIALS AND METHODS: To select an item set in the visuospatial performance test, two questionnaires with similar difficulty were developed through group testing. A group test was administered to 263 college students. Two types of questionnaire containing 20 questions were developed to measure the ability of visuospatial cognition. Eight college students (right-handed male, average age of 23.5 yrs) were examined for fMRI study. The experiment consisted of two runs of the visuospatial cognition testing, one with 21% level of oxygen and the other with 30% oxygen level. Each run consisted of 4 blocks, each containing control and visuospatial items. Functional brain images were taken from 3T MRI using the single-shot EPI method. Using the subtraction procedure, activated areas in the brain during visuospatial tasks were col-orcoded by t-score. To investigate the time course data in each activated area from brain images, 4 typical regions (cerebellum, occipital lobe, parietal lobe, and frontal lobe) were selected. RESULTS: The average accuracy was 50.63 +/-8.63 and 62.50 +/-9.64 for 21% and 30% oxygen respectively, and a statistically significant difference was found in the accuracy between the two types of oxygen (p<0.05). There were more activation areas observed at the cerebellum, occipital lobe, parietal lobe and frontal lobe with 30% oxygen administration. The rate of increase in the cerebellum, occipital lobe and parietal lobe was 17% and that of the frontal lobe, 50%. Especially, there were increase of intensity of BOLD signal at the parietal lobe with 30% oxygen administration. The increase rate of the left parietal lobe was 1.4% and that of the right parietal lobe, 1.7%. CONCLUSION: It is concluded that while performing visuospatial tasks, high concentrations of oxygen administration make oxygen administration sufficient, thus making neural network activate more, and the ability to perform visuospatial tasks increase.

Observations of Oxygen Administration Effects on Visuospatial Cognitive Performance using Time Course Data Analysis of fMRI

PURPOSE: This study attempted to investigate the effects of supply of highly concentrated (30%) oxygen on human ability of visuospatial cognition using time course data analysis of functional Magnetic Resonance Imaging (fMRI). MATERIALS AND METHODS: To select an item set in the visuospatial performance test, two questionnaires with similar difficulty were developed through group testing. A group test was administered to 263 college students. Two types of questionnaire containing 20 questions were developed to measure the ability of visuospatial cognition. Eight college students (right-handed male, average age of 23.5 yrs) were examined for fMRI study. The experiment consisted of two runs of the visuospatial cognition testing, one with 21% level of oxygen and the other with 30% oxygen level. Each run consisted of 4 blocks, each containing control and visuospatial items. Functional brain images were taken from 3T MRI using the single-shot EPI method. Using the subtraction procedure, activated areas in the brain during visuospatial tasks were col-orcoded by t-score. To investigate the time course data in each activated area from brain images, 4 typical regions (cerebellum, occipital lobe, parietal lobe, and frontal lobe) were selected. RESULTS: The average accuracy was 50.63 +/-8.63 and 62.50 +/-9.64 for 21% and 30% oxygen respectively, and a statistically significant difference was found in the accuracy between the two types of oxygen (p<0.05). There were more activation areas observed at the cerebellum, occipital lobe, parietal lobe and frontal lobe with 30% oxygen administration. The rate of increase in the cerebellum, occipital lobe and parietal lobe was 17% and that of the frontal lobe, 50%. Especially, there were increase of intensity of BOLD signal at the parietal lobe with 30% oxygen administration. The increase rate of the left parietal lobe was 1.4% and that of the right parietal lobe, 1.7%. CONCLUSION: It is concluded that while performing visuospatial tasks, high concentrations of oxygen administration make oxygen administration sufficient, thus making neural network activate more, and the ability to perform visuospatial tasks increase.

The Volumetric Study of the Ventricle in Korean according to Age and Gender / 대한해부학회지

The purpose of this study is to measure the standard volume of the ventricle of normal Koreans in their 20s and 40s and find out difference in the volume of the ventricle according to age and gender. We collected MR brain images from 118 people in their 20s (male 58, female 60)and 100 people in their 40s (male 41, female 59), so a total of 218 people.For each of sagittal, coronal and axial sections, the ventricular part was segmented using automatic and manual methods, and the volume was measured. In order to observe difference according to age and gender and to observe the interactive effect between age and gender, two-way ANOVA was carried out using age (2 levels)and gender (2 levels)as independent variables. The average volume of the ventricle of Koreans in their 20 s was 16.2 [cm3]and that of Koreans in their 40s was 23.1 [cm3].The average volume of the ventricle of male Koreans in their 20s and 40s was 21.9 [cm3]and that of female Koreans was 17.5 [cm3].The volume of the ventricle was significantly larger in Koreans in their 40s than those in their 20s, and in male Koreans than n female ones. Moreover, the increase of the volume of the ventricle with age was significantly larger in male Koreans than in female ones. According to the results of measuring the volume of the ventricle of normal Koreans in their 20s and 40s, the volume was significantly different according to age and gender, and the increase of the volume of the ventricle with age was significantly larger in men than in women.

Measuring of the Cerebellar Volume of Normal Koreans in Their 20s and 40s Using Magnetic Resonance Imaging

PURPOSE: This study purposed to measure the standard volume of the cerebellum of normal Koreans who were in their 20s and 40s, and we also wished to find out the difference in the volume of the cerebellum according to gender and age. MATERIALS AND METHODS: This study collected MR brain images from 118 people in their 20s (males: 58, females: 60) and 100 people in their 40s (males: 41, females: 59), for a total of 218 people. For each of sagittal, coronal and axial sections, the cerebellar part of the images was segmented using automatic and manual methods, and the volume was then measured. In order to observe differences according to gender and age and also to observe the interactive effect between gender and age, a two-way ANOVA test was performed using gender (2 levels) and age (2 levels) as independent variables. RESULTS:The average volume of the cerebellum of Koreans in their 20s was 133.74 (cm3) and that of Koreans in their 40s was 121.83 (cm3). The average volume of the cerebellum of male Koreans in their 20s and 40s was 134.55 (cm3) and that of female Koreans was 123.06 (cm3). The volume of the cerebellum was significantly larger in Koreans in their 20s than those volumes of the cerebellum of Koreans in their 40s, and the cerebellum volumes in male Koreans were larger than those of the Korean females. Moreover, the reduction of the volume of the cerebellum with age was significantly larger in male Koreans than in the Korean females. CONCLUSION: According to the results of measuring the volume of the cerebellum for normal Koreans in their 20s and 40s, the volume was significantly different according to gender and age, and the reduction of the volume of the cerebellum with age was significantly larger in men than in women.

Development of Korean Standard Brain Templates According to Gender and Age / 대한해부학회지

Researches on brain functions using MRI or PET generally involve the process that normalizes spatially the results of functional images into a standard brain template in order to find out a common activation area of multiple subjects. So far MNI305, which is Western people's standard brain template, has been commonly used. However, the brain may be different morphologically and structurally among human races, so the use of MNI305 may produce inaccurate results. Furthermore, because the size and shape of the brain vary according to gender and age, if brain temperatures are developed considering these factors, brain activation areas may be identified more precisely. This study collected MR brain images from 121 men and women in their 20s (23.0 +/-2.6 years on the average) and 99 men and women in their 40s (47.5 +/-3.7 years on the average). After eight reference points were defined using the method proposed by Nowinski, the image that had the least error from the mean distances among the reference points was selected as the representative brain image. All images were affine-transformed into the representative brain image, and average brain templates were created by age and gender through averaging the brightness of images. The results of this study may be utilized in Korean brain probability maps to be developed in the future for more precise research on the functions of Koreans' brain.

The Effects of TENS in a New Rat Model of Neuropathic Pain

OBJECTIVE: To evaluate the effects of high and low frequency transcutaneous electrical stimulation (TENS) on the neuropathic pain and to determine opioid-system involve to analgesia. METHOD: Under pentobarbital anesthesia (55 mg/kg i.p.), twenty male Sprague-Dawley (250~300 g) rats were operated that tibial and sural nerves were ligated and cut unilaterally. Pain sensitivity was assessed using the von Frey filament (8 mN) and acetone through behavioral test. After neuropathic pain developed, the various modes of TENS were applied to the rat with neuropathic pain and pain sensitivity was assessed to evaluate the analgesic effects. Naloxone was injected intraperitoneally to observe reversal of pain sensitivity. RESULTS: 1) Neuropathic pain was obtained successfully through selective cut of sciatic nerve branches in the rat. 2) Neuropathic pain were reduced by more than 10 minutes stimulation of TENS. 3) The analgesic effects of TENS on mechanical and cold stimulation were sustained for 60 minutes and 30 minutes, respectively. 4) Both high and low frequency TENS showed analgesic effects. 5) Analgesic effects of TENS were reversed by the intraperitoneal administration of naloxone. CONCLUSION: The results suggest that low and high frequency TENS have an analgesic effects to neuropathic pain and opioid-system was involved to reduce of neuropathic pain.