Comparative Functional Connectivity of Core Brain Regions between Implicit and Explicit Memory Tasks Underlying Negative Emotion in General Anxiety Disorder

Objective@#To investigate not only differential patterns of functional connectivity of core brain regions between implicit and explicit verbal memory tasks underlying negatively evoked emotional condition, but also correlations of functional connectivity (FC) strength with clinical symptom severity in patients with generalized anxiety disorder (GAD). @*Methods@#Thirteen patients with GAD and 13 healthy controls underwent functional magnetic resonance imaging for memory tasks with negative emotion words. @*Results@#Clinical symptom and its severities of GAD were potentially associated with abnormalities of task-based FC with core brain regions and distinct FC patterns between implicit vs. explicit memory processing in GAD were potentially well discriminated. Outstanding FC in implicit memory task includes positive connections of precentral gyus (PrG) to inferior frontal gyrus and inferior parietal gyrus (IPG), respectively, in encoding period; a positive connection of amygdala (Amg) to globus pallidus as well as a negative connection of Amg to cerebellum in retrieval period. Meanwhile, distinct FC in explicit memory included a positive connection of PrG to inferior temporal gyrus (ITG) in encoding period; a positive connection of the anterior cingulate gyrus to superior frontal gyrus in retrieval period. Especially, there were positive correlation between GAD-7 scores and FC of PrG-IPG (r2 = 0.324, p = 0.042) in implicit memory encoding, and FC of PrG-ITG (r2 = 0.378, p = 0.025) in explicit memory encoding. @*Conclusion@#This study clarified differential patterns of brain activation and relevant FC between implicit and explicit verbal memory tasks underlying negative emotional feelings in GAD. These findings will be helpful for an understanding of distinct brain functional mechanisms associated with clinical symptom severities in GAD.

MRI-Based Multimodal Approach to the Assessment of Clinical Symptom Severity of Obsessive-Compulsive Disorder

Objective@#This study assessed the associations of the abnormal brain activation and functional connectivity (FC) during memory processing and brain volume alteration in conjunction with psychiatric symptom severity in patients with obsessive-compulsive disorder (OCD). @*Methods@#Twenty-OCD patients and 20-healthy controls (HC) underwent T1-weighted and functional imaging underlying explicit memory task. @*Results@#In memory encoding, OCD patients showed higher activities in right/left (Rt./Lt.) inferior temporal gyrus (ITG), medial prefrontal cortex (MPFC), dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), compared with HC. In task-based FC, caudate (Cd) was positively connected with DLPFC and ITG in OCD, while HC showed different connectivities of Cd-ACC and Rt.-Lt. ITG. In memory retrieval, only Cd was activated in OCD patients. Cd was positively connected with DLPFC and vmPFC in OCD, but negatively connected between same brain areas in HC. OCD patients showed increased gray matter (GM) volumes of cerebellum, DLPFC, orbitofrontal cortex (OFC), hippocampus, Cd and ITG, and concurrently, increased white matter volumes of DLPFC. In OCD patients, GM volumes of Cd and OFC were positively correlated with HAMA and Y-BOCS. Functional activity changes of Cd in OCD were positively correlated with Y-BOCS. @*Conclusion@#Our findings support to accessing clinical symptom and its severity linked by brain structural deformation and functional abnormality in OCD patients.

Neural Mechanism of Second Language Processing in Korean-English Bilingual Children

PURPOSE@#To evaluate the neural mechanism of second language processing in Korean-English bilingual children using functional MRI (fMRI).@*MATERIALS AND METHODS@#The study was conducted on 20 Korean elementary school children who were learning English as a foreign language. fMRI was performed during short-passage comprehension tasks in Korean and English languages. We analyzed which brain areas were activated according to the language, English proficiency, and task difficulty.@*RESULTS@#Higher activities were observed in the dorsolateral prefrontal cortex, supplementary motor area, precentral gyrus, left basal ganglia, and left temporoparietal and occipital lobes during English comprehension than during Korean comprehension. The low English proficiency group showed higher activities than the high English proficiency group in the frontotemporal cortex, including the prefrontal cortex. Higher activities were observed in the right inferior frontal gyrus and right temporoparietal lobe during the English comprehension task of intermediate difficulty compared to that of low difficulty. However, the brain activities significantly decreased while performing a high-difficulty English task.@*CONCLUSION@#Brain activities significantly increased during English comprehension in the lower English proficiency group while performing an intermediate-difficulty task. However, brain activation decreased when the task difficulty exceeded the moderate comprehension level. These results suggest that a proper level of education is important to learn a second language.

Brain Activation Patterns Associated with the Effects of Emotional Distracters during Working Memory Maintenance in Patients with Generalized Anxiety Disorder

Few studies have assessed the neural mechanisms of the effects of emotion on cognition in generalized anxiety disorder (GAD) patients. In this functional MRI (fMRI), we investigated the effects of emotional interference on working memory (WM) maintenance in GAD patients. Fifteen patients with GAD participated in this study. Event-related fMRI data were obtained while the participants performed a WM task (face recognition) with neutral and anxiety-provoking distracters. The GAD patients showed impaired performance in WM task during emotional distracters and showed greater activation on brain regions such as DLPFC, VLPFC, amygdala, hippocampus which are responsible for the active maintenance of goal relevant information in WM and emotional processing. Although our results are not conclusive, our finding cautiously suggests the cognitive-affective interaction in GAD patients which shown interfering effect of emotional distracters on WM maintenance.

Single Photon Emission Computerized Tomography and Neuropsychological Tests That Predict a Good Response to Donepezil Therapy for Alzheimer's Disease

BACKGROUND AND PURPOSE: Cholinesterase inhibitors (ChEIs) are effective in Alzheimer's disease (AD) treatment. The aim of this study is 1) to find neuropsychological factors that affect the functional response to ChEI therapy and 2) to determine whether regional cerebral blood flow (rCBF) pretreatment predicts a cognitive change in response to ChEI. METHODS: We prospectively recruited 32 patients diagnosed with probable AD and treated them with donepezil, a ChEI, over one year. The patients were divided into stable (s-AD) and declined (d-AD) AD groups, based on changes in Korean version of Mini-Mental State Examination (K-MMSE) scores. Patients were assessed using the Alzheimer's Disease Co-operative Study-Activities of Daily Living (ADCS-ADL) and Seoul Neuropsychologic Screening Battery, as well as brain single photon emission computerized tomography (SPECT) at baseline and last medical evaluations. The predictors of therapeutic responses were analyzed using general linear models. RESULTS: Based on their cognitive function changes, AD patients were classified into two groups: s-AD (n=14, annual change in K-MMSE score or =0.9). The s-AD at baseline showed significantly better ADCS-ADL function (p=0.04) and had a tendency to preserve frontal function compared to the d-AD group. Global Statistical Parametric Mapping analysis revealed no significant decrease of rCBF between baseline and follow-up SPECT, in either the s-AD or the d-AD groups. However, on regional perfusion analysis of baseline SPECT, the d-AD group demonstrated perfusion deficits in the supramarginal gyrus, inferior occipital gyrus, and rolandic operculum compared with the s-AD group. CONCLUSIONS: Highly preserved ADCS-ADLs predicted a better improvement in MMSE scores in response to ChEI therapy and a more positive functional response in the group with preserved frontal function. rCBF provided hints to the variable response to donepezil therapy with ChEI treatment.

Brain Activation in Response to Visually Evoked Sexual Arousal in Male-to-Female Transsexuals: 3.0 Tesla Functional Magnetic Resonance Imaging

OBJECTIVE: This study used functional magnetic resonance imaging (fMRI) to contrast the differential brain activation patterns in response to visual stimulation with both male and female erotic nude pictures in male-to-female (MTF) transsexuals who underwent a sex reassignment surgery. MATERIALS AND METHODS: A total of nine healthy MTF transsexuals after a sex reassignment surgery underwent fMRI on a 3.0 Tesla MR Scanner. The brain activation patterns were induced by visual stimulation with both male and female erotic nude pictures. RESULTS: The sex hormone levels of the postoperative MTF transsexuals were in the normal range of healthy heterosexual females. The brain areas, which were activated by viewing male nude pictures when compared with viewing female nude pictures, included predominantly the cerebellum, hippocampus, putamen, anterior cingulate gyrus, head of caudate nucleus, amygdala, midbrain, thalamus, insula, and body of caudate nucleus. On the other hand, brain activation induced by viewing female nude pictures was predominantly observed in the hypothalamus and the septal area. CONCLUSION: Our findings suggest that distinct brain activation patterns associated with visual sexual arousal in postoperative MTF transsexuals reflect their sexual orientation to males.

Effects of Antidepressant Treatment on Sexual Arousal in Depressed Women: A Preliminary fMRI Study

OBJECTIVE: There was a recent study to explore the cerebral regions associated with sexual arousal in depressed women using functional magnetic resonance imaging (fMRI). The purpose of this neuroimaging study was to investigate the effects of antidepressant treatment on sexual arousal in depressed women. METHODS: Seven depressed women with sexual arousal dysfunction (mean age: 41.7+/-13.8, mean scores of the Beck Depression Inventory (BDI) and the 17-item Hamilton Rating Scale for Depression (HAMD-17): 35.6+/-7.1 and 34.9+/-3.1, respectively) and nine healthy women (mean age: 40.3+/-11.6) underwent fMRI before and after antidepressant treatment. The fMRI paradigm contrasted a 1 minute rest period viewing non-erotic film with 4 minutes of sexual stimulation viewing an erotic video film. Data were analyzed by SPM 2. The relative number of pixels activated in each period was used as an index of activation. All depressed women were treated with mirtazapine (mean dosage: 37.5 mg/day) for 8 to 10 weeks. RESULTS: Levels of brain activity during sexual arousal in depressed women significantly increased with antidepressant treatment (p<0.05) in the regions of the hypothalamus (3.0% to 11.2%), septal area (8.6% to 27.8%) and parahippocampal gyrus (5.8% to 14.6%). Self-reported sexual arousal during visual sexual stimulation also significantly increased post-treatment, and severity of depressive symptoms improved, as measured by the BDI and HAMD-17 (p<0.05). CONCLUSION: These results show that sexual arousal dysfunction of depressed women may improve after treatment of depression, and that this improvement is associated with increased activation of the hypothalamus, septal area, and parahippocampal gyrus during sexual arousal.

Neuro-Anatomical Evaluation of Human Suitability for Rural and Urban Environment by Using fMRI / 의학물리

The purpose of this study was to identify different cerebral areas of the human brain associated with rural and urban picture stimulation using a 3.0 Tesla functional magnetic resonance imaging (fMRI) and further to investigate the human suitability for rural and urban environments. A total of 27 right-handed participants (mean age: 27.3+/-3.7) underwent fMRI study on a 3.0T MR scanner. The brain activation patterns were induced by visual stimulation with each rural and urban sceneries. The participants were divided into two groups as 26 subjects favorable to rural scenery and 14 subjects unfavorable to urban scenery based on their filled-in questionnaire. The differences of the brain activation in response to two extreme types of pictures by the two sample t-test were characterized as follows: the activation areas observed in rural scenery over urban were the insula, middle frontal gyrus, precuneus, caudate nucleus, superior parietal gyrus, superior occipital gyrus, fusiform gyrus, and globus pallidus. In urban scenery over rural, the inferior frontal gyrus, parahippocampal gyrus, postcentral gyrus, superior temporal gyrus, amygdala, and posterior cingulate gyrus were activated. The fMRI patterns also clearly show that rural scenery elevated positive emotion such as happiness and comfort. On the contrary, urban scenery elevated negative emotion, resulting in activation of the amygdala which is the key region for the feelings of fear, anxiety and unpleasantness. This study evaluated differential cerebral areas of the human brain associated with rural and urban picture stimulation using a 3.0 Tesla fMRI. These findings will be useful as an objective evaluation guide to human suitability for ecological environments that are related to brain activation with joy, anger, sorrow and pleasure.

Functional Neuroanatomy Associated with Natural and Urban Scenic Views in the Human Brain: 3.0T Functional MR Imaging

OBJECTIVE: By using a functional magnetic resonance imaging (fMRI) technique we assessed brain activation patterns while subjects were viewing the living environments representing natural and urban scenery. MATERIALS AND METHODS: A total of 28 healthy right-handed subjects underwent an fMRI on a 3.0 Tesla MRI scanner. The stimulation paradigm consisted of three times the rest condition and two times the activation condition, each of which lasted for 30 and 120 seconds, respectively. During the activation period, each subject viewed natural and urban scenery, respectively. RESULTS: The predominant brain activation areas observed following exposure to natural scenic views in contrast with urban views included the superior and middle frontal gyri, superior parietal gyrus, precuneus, basal ganglia, superior occipital gyrus, anterior cingulate gyrus, superior temporal gyrus, and insula. On the other hand, the predominant brain activation areas following exposure to urban scenic views in contrast with natural scenes included the middle and inferior occipital gyri, parahippocampal gyrus, hippocampus, amygdala, anterior temporal pole, and inferior frontal gyrus. CONCLUSION: Our findings support the idea that the differential functional neuroanatomies for each scenic view are presumably related with subjects' emotional responses to the natural and urban environment, and thus the differential functional neuroanatomy can be utilized as a neural index for the evaluation of friendliness in ecological housing.

Time-Course Analysis of the Neuroanatomical Correlates of Sexual Arousal Evoked by Erotic Video Stimuli in Healthy Males

OBJECTIVE: To assess the dynamic activations of the key brain areas associated with the time-course of the sexual arousal evoked by visual sexual stimuli in healthy male subjects. MATERIALS AND METHODS: Fourteen right-handed heterosexual male volunteers participated in this study. Alternatively combined rest period and erotic video visual stimulation were used according to the standard block design. In order to illustrate and quantify the spatiotemporal activation patterns of the key brain regions, the activation period was divided into three different stages as the EARLY, MID and LATE stages. RESULTS: For the group result (p < 0.05), when comparing the MID stage with the EARLY stage, a significant increase of the brain activation was observed in the areas that included the inferior frontal gyrus, the supplementary motor area, the hippocampus, the head of the caudate nucleus, the midbrain, the superior occipital gyrus and the fusiform gyrus. At the same time, when comparing the EARLY stage with the MID stage, the putamen, the globus pallidus, the pons, the thalamus, the hypothalamus, the lingual gyrus and the cuneus yielded significantly increased activations. When comparing the LATE stage with the MID stage, all the above mentioned brain regions showed elevated activations except the hippocampus. CONCLUSION: Our results illustrate the spatiotemporal activation patterns of the key brain regions across the three stages of visual sexual arousal.

Parietal Intraparenchymal Schwannoma: Case Report

We report a case of an intraparenchymal schwannoma of the left parietal lobe. A 51-year-old woman was admitted to our hospital with complaints of intermittent headaches. Computed tomography and magnetic resonance images revealed a 1.3 cm sized intra-axial homogeneous enhancing mass in the left parietal lobe. The lesion was pathologically confirmed to be a schwannoma.

The Usefulness of In Vitro Proton Magnetic Resonance Spectroscopy for Differentiating Between Abdominal Body Fluids

PURPOSE: The purpose of this study was to determine whether in vitro proton (1H) magnetic resonance spectroscopy (MRS) is useful for distinguishing between abdominal types of fluids. MATERIALS AND METHODS: Thirty fluid samples that were obtained from patients who were undergoing diagnostic or therapeutic percutaneous drainage of abdominal fluids were examined in this study. According to their gross appearance and smell, each sample was classified as either purulent fluid (n=12) or non-purulent fluid (n=18). The non-purulent fluids were subdivided into hemorrhagic fluid (n=2), serosanguinous fluid with debris (n=2), and serosanguinous fluid without debris (n=14). In addition, according to the cytologic analysis, each sample was classified as either benign fluid (n=23) or malignant fluid (n=7). A set of humoral pathological examinations that included biochemical analysis and culture of the fluid were performed for all the fluid samples. In vitro 1H MRS was performed by using a 1.5T MR system and a birdcage head coil. MR spectra were obtained by using point-resolved spectroscopy (PRESS) (TR/TE=2000/30 msec) with water suppression. The MR spectra were analyzed on the basis of agreement between a radiologist and a physicist who worked in consensus. RESULTS: The MR spectra obtained from 30 samples could be classified into 8 different patterns, according to the presence of lipid (0.9/1.3 ppm), lactate (1.3 ppm), acetate (1.9 ppm), and succinate (2.4 ppm) peaks. The MR spectral patterns of the purulent fluids (n=12) were classified as follows: pattern-1 (n=7, 58%), pattern-2 (n=2, 17%), pattern-3 (n=1, 8%), pattern-6 (n=1, 8%) and pattern-8 (n=1, 8%). The MR spectral patterns of the non-purulent fluids (n=18) were classified as follows: pattern-4 (n=1, 6%), pattern-5 (n=5, 28%), pattern-6 (n=1, 6%), pattern-7 (n=3, 17%) and pattern-8 (n=8, 44%). The MR spectral patterns of the purulent fluids were significantly different from those of the non-purulent fluids (p < .05). The MR spectral patterns of benign fluids (n=23) were classified as follows: pattern-1 (n=7, 30%), pattern-2 (n=2, 9%), pattern-3 (n=1, 4%), pattern-4 (n=1, 4%), pattern-5 (n=3, 13%), pattern-6 (n=2, 9%), pattern-7 (n=1, 4%) and pattern-8 (n=6, 26%). The MR spectral patterns of malignant fluids (n=7) were classified as follows: pattern-5 (n=2, 29%), pattern-7 (n=2, 29%) and pattern-8 (n=3, 43%). No significant difference was found between the spectral patterns of the benign and malignant fluids (p= .300). CONCLUSION: In vitro 1H MRS could be useful for differentiating between purulent fluid and non-purulent fluid.

Malignant Solitary Pulmonary Nodule: Enhancement Patterns on Contrast-enhanced Dynamic CT with the Histopathologic Evaluation

PURPOSE: We wanted to evaluate the potential role of dynamic incremental computed tomography (CT) for making the diagnosis of malignant solitary pulmonary nodule (SPN) by investigating the dynamic enhancement patterns. MATERIALS AND METHODS: Forty patients with presumed malignant SPN (diameter 0.05). CONCLUSION: Dynamic incremental chest CT was useful for making the diagnosis of malignant SPN that showed an established dynamic contrast enhancement pattern regardless of the histopatholgic subtypes.

The Usefulness of Diffusion Tensor MRI for the Prediction of Clinical Outcome in Patients with Acute Subcortical Infarction

BACKGROUND: Diffusion tensor MRI (DTI) is a new imaging technique and enables us to analyze the structural damage of fiber pathways and to monitor the time course of Wallerian degeneration of the pyramidal tract in stroke patients. We used DTI to investigate structural changes of the infarct area and the associated descending corticospinal tract in patients with subcortical infarct. METHODS: We examined 24 consecutive patients who presented with acute single cerebral infarct in the subcortical area and who also had undergone an MRI study within 7 days after symptom onset. Clinical outcome was assessed using the National Institutes of Health Stroke Scale (NIHSS) at admission, 7 days, 14 days and 30 days and modified Rankin Scale (mRS) at admission and 30 days. Each of the indices was achieved by post processing the acquired DTI data and correlated with the NIHSS. RESULTS: In infarct region, fractional anisotropy (FA) was significantly decreased compared with matched-contralateral regions (0.39 vs. 0.53, p<0.001). In the distal to the infarct, FA was significantly decreased at internal capsule (0.62 vs. 0.64, p=0.019), not at pons (0.51 vs. 0.53, p=0.103). The decrease of anisotropy at infarct region correlated positively with the NIHSS at 7, 14 and 30 days and mRS at 30 days after stroke, but the decrease of anisotropy at internal capsule did not correlate with the NIHSS. CONCLUSIONS: This study shows the potential of DTI to detect and monitor the structural degeneration of fiber pathways and to establish the prognosis in patients with acute subcortical cerebral infarct.

Diffusion-Weighted MR Imaging of Neuro-Behcet's Disease: Initial and Follow-up Studies

PURPOSE: To assess the usefulness of diffusion-weighted MR imaging (DWI) and apparent diffusion coefficient (ADC) in the initial and follow-up studies of patients with neuro-Behcet's disease. MATERIALS AND METHODS: Six patients diagnosed with neuro-Behcet's disease were the subjects of this study. Initial and follow-up MR imaging were obtained in all six patients. Initial and follow-up DWI were also obtained in four of the six patients, with only an initial DWI in the other two. The DWI were obtained using multi-shot echo planar imaging, on a 1.5T MR unit, with two gradient steps (b values of 0, 1000 sec/mm2). The ADC value and ADC maps were obtained using commercial software. The locations and signal intensities of the lesions were analyzed on conventional MRI and DWI, respectively. The ADC values of the lesions were calculated on the initial and follow-up DWI, and compared those of lesions in the normal contralateral regions. RESULTS:The initial DWI showed iso-signal intensities in four of the six patients, with high signal intensities in the other two. In five of the six patients, including three of the four that showed isosignal intensities and the two that showed high signal intensities on the initial DWI, the ADC values of the involved lesions were higher than those of the normal contralateral regions. In three of four that showed isosignal intensities, the ADC values of the lesions were decreased and normalized on the follow-up DWI. CONCLUSION: Obtaining DWI and ADC values in patients with neuro-Behcet's disease may be helpful in the understanding of pathophysiology and differential diagnosis of this disease.

Functional MR Imaging of Psychogenic Amnesia: A Case Report

We present here a case in which functional MR imaging (fMRI) was done for a patient who developed retrograde psychogenic amnesia for a four year period of her life history after a severe stressful event. We performed the fMRI study for a face recognition task using stimulation with three kinds of face photographs: recognizable familiar faces, unrecognizable friends' faces due to the psychogenic amnesia, and unfamiliar control faces. Different activation patterns between the recognizable faces and unrecognizable faces were found in the limbic area, and especially in the amygdala and hippocampus.

Usefulness of Apparent Diffusion Coefficient in Ovarian Cystic Tumors Using Diffusion-Weighted Magnetic Resonance Imaging

PURPOSE: To evaluate the usefulness of apparent diffusion coefficient (ADC) values using diffusion-weighted magnetic resonance imaging (DWI) in patients with ovarian cystic tumors. MATERIALS AND METHODS: During past 12 months, we studied 30 patients who were clinically suspected of having ovarian cystic tumors and who underwent DWI using a 1.5 T MR unit. Eight patients with small cystic ovarian lesions of less than 3 cm in diameter and insufficient DWI were excluded from the calculation of the ADC values. The remaining twenty-six cystic ovarian lesions in 22 patients were classified into four groups; ovarian cysts, cystadenomas, other benign tumors, and malignant tumors. DWI was obtained using single-shot spin echo planar imaging and two gradient steps (b values of 0, 800 sec/mm2). The ADC values were measured using regions-of-interest (ROI) in the cystic components of the DWI located in the same section as the T2-weighted image and away from the septation and solid components. RESULTS: The mean ADC values were 0.196+/-0.105x10(-3) mm2/sec in the ovarian cysts, 1.312+/-1.064x10(-3) mm2/sec in the cystadenomas, 0.274+/-0.124x10(-3) mm2/sec in the other benign tumors, and 1.011+/-0.080x10(-3) mm2/sec in the malignant tumors. The differences in the ADC values between the ovarian cysts and cystadenomas, the ovarian cysts and malignant tumors, the cystadenomas and other benign tumors, and the other benign tumors and malignant tumors were statistically significant (p 0.05). CONCLUSION: The calculated ADC values using DWI should be helpful in the differential diagnosis of cystic ovarian tumors.

Diagnostic Usefulness of Perilesional Edema around Intracerebral Hemorrhage in Predicting Underlying Causes

PURPOSE: We attempted to evaluate the diagnostic usefulness of the degree of perilesional edema around intracerebral hematoma in predicting the underlying cause. MATERIALS AND METHODS: This study included 54 patients with intracerebral hematoma for whom the underlying cause was confirmed by biopsy, radiological or clinical methods. Cases of subarachnoid hemorrhage, hemorrhagic transformation of cerebral infarction and intraventricular hemorrhage were excluded. The lesion size was defined as the average value of the longest axis and the axis perpendicular to this. The size of the perilesional edema was defined as the longest width of the edema. In all cases, the sizes of the lesion and edema were measured on the T2 weighted image. We defined the edema ratio as the edema size divided by the lesion size. RESULTS:23 cases were diagnosed as intracerebral hemorrhage due to neoplastic conditions, such as metastasis (n=17), glioblastoma (n=5), hemangioblastoma(n=1). 31 cases were caused by non-neoplastic conditions, such as spontaneous hypertensive hemorrhage (n=23), arteriovenous malformation (n=4), cavernous angioma (n=3), and moya-moya disease (n=1). In fourteen cases, which were confirmed as malignant intracerebral hemorrhage, the edema ratio was more than 100%. Of the other cases, only 8 were confirmed as malignant intracerebral hemorrhage. It was found that the larger the edema ratio, the more malignant the intracerebral hemorrhage, and this result was statistically significant (p<0.001). CONCLUSION: Measurement of perilesional edema and the intracerebral hematoma ratio may be useful in predicting the underlying causes.

Cerebral Activation Associated with Visually Evoked Sexual Arousal in the Limbic System: Functional MR Imaging

PURPOSE: To identify the brain centers associated with visually evoked sexual arousal in the human brain, and to investigate the neural mechanism for sexual arousal using functional MRI (fMRI). MATERIALS AND METHODS: A total of 20 sexually potent volunteers consisting of 10 males (mean age: 24) and 10 females (mean age: 23) underwent fMRI on a 1.5 T MR scanner (GE Signa Horizon). The fMRI data were obtained from 7 slices (10 mm slice thickness) parallel to the AC-PC (anterior commissure and posterior commissure) line, giving a total of 511 MR images. The sexual stimulation consisted of a 1-minute rest with black screen, followed by a 4-minute stimulation by an erotic video film, and concluded with a 2-minute rest. The brain activation maps and their quantification were analyzed by the statistical parametric mapping (SPM 99) program. RESULTS: The brain activation regions associated with visual sexual arousal in the limbic system are the posterior cingulate gyrus, parahippocampal gyrus, hypothalamus, medial cingulate gyrus, thalamus, amygdala, anterior cingulate gyrus, insula, hippocampus, caudate nucleus, globus pallidus and putamen. Especially, the parahippocampal gyrus, cingulate gyrus, thalamus and hypothalamus were highly activated in comparison with other areas. The overall activities of the limbic lobe, diencephalon, and basal ganglia were 11.8%, 10.5%, and 3.4%, respectively. In the correlation test between brain activity and sexual arousal, the hypothalamus and thalamus showed positive correlation, but the other brain areas showed no correlation. CONCLUSION: The fMRI is useful to quantitatively evaluate the cerebral activation associated with visually evoked, sexual arousal in the human brain. This result may be helpful by providing clinically valuable information on sexual disorder in humans as well as by increasing the understanding of the neuroanatomical correlates of sexual arousal.

Qualitative and Quantitative Measurement of Human Brain Activity Using Pixel Subtraction Algorithm

PURPOSE: To develop an automated quantification program, which is called FALBA (Functional & Anatomical Labeling of Brain Activation), and to provide information on the brain centers, brain activity (%) and hemispheric lateralization index on the basis of a brain activation map obtained from functional MR imaging. MATERIALS AND METHODS: The 3-dimensional activation MR images were processed by a statistical parametric mapping program (SPM99, The Wellcome Department of Cognitive Neurology, University College London, UK) and MRIcro software (www.mricro.com). The 3-dimensional images were first converted into 2-dimensional sectional images, and then overlapped with the corresponding T1-weighted images. Then, the image dataset was extended to -59 mm to 83 mm with a 2 mm slice-gap, giving 73 axial images. By using a pixel subtraction method, the differences in the R, G, B values between the T1-weighted images and the activation images were extracted, in order to produce black & white (B/W) differentiation images, in which each pixel is represented by 24-bit R, G, B true colors. Subsequently, another pixel differentiation method was applied to two template images, namely one functional and one anatomical index image, in order to generate functional and anatomical differentiation images containing regional brain activation information based on the Brodmann's and anatomical areas, respectively. In addition, the regional brain lateralization indices were automatically determined, in order to evaluate the hemispheric predominance, with the positive (+) and negative (-) indices showing left and right predominance, respectively. RESULTS: The manual counting method currently used is time consuming and has limited accuracy and reliability in the case of the activated cerebrocortical regions. The FALBA program we developed was 240 times faster than the manual counting method: -10 hours for manual accounting and -2.5 minutes for the FALBA program using a Pentium IV processor. Compared with the FALBA program, the manual quantification method showed an average error of 0.334+/-0.007 (%). Thus, the manual counting method gave less accurate quantitative information on brain activation than the FALBA program. CONCLUSION: The FALBA program is capable of providing accurate quantitative results, including the identification of the brain activation region and lateralization index with respect to the functional and anatomical areas. Also, the processing time was dramatically shortened in comparison with the manual counting method.