Rahyeong Juh

Cerebral glucose metabolism in corticobasal degeneration comparison with progressive supranuclear palsy using statistical mapping analysis

This study measured the cerebral glucose metabolism in patients suffering from corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). The aim was to determine if there is a different metabolic pattern using (18)F-labeled 2-deoxyglucose ((18)F-FDG) positron emission tomography (PET). The regional cerebral glucose metabolism was examined in 8 patients diagnosed clinically with CBD (mean age 69.6 +/- 7.8 years; male/female: 5/3), 8 patients with probable PSP (mean age 67.8 +/- 4.5 years; male/female: 4/4) and 22 healthy controls. The regional cerebral glucose metabolism between the three groups was compared using statistical parametric mapping (SPM) with a voxel-by-voxel approach (p < 0.001, 200-voxel level). Compared with the normal controls, asymmetry in the regional glucose metabolism was observed in the parietal, frontal and cingulate in the CBD patients. In the PSP patients, the glucose metabolism was lower in the orbitofrontal, middle frontal, cingulate, thalamus and mid-brain than their age matched normal controls. A comparison of the two patient groups demonstrated relative hypometabolism in the thalamus, the mid-brain in the PSP patients and the parietal lobe in CBD patients. These results suggest that when making a differential diagnosis of CBD and PSP, voxel-based analysis of the (18)F-FDG PET images using a SPM might be a useful tool in clinical examinations.

Voxel based comparison of glucose metabolism in the differential diagnosis of the multiple system atrophy using statistical parametric mapping

OBJECTIVE A differential diagnosis of idiopathic parkinsonian disease (IPD) and multiple system atrophy (MSA) is difficult due to their common signs and symptoms. The aim of this 18F-2-fluoro-2 deoxyglucose (18F-FDG) positron emission tomography (PET) study was to compare the regional cerebral glucose metabolism in MSA with that in IPD by statistical parametric mapping (SPM) and image registration. METHODS The 18F-FDG PET images of MSA and IPD patients were assessed by SPM and image registration to determine metabolic patterns that may be useful in differentiating between the two groups. Eleven patients with MSA, eight patients with IPD and 22 healthy controls participated in the study. RESULTS The IPD patients were found to have a significant glucose hypometabolism in comparison with the healthy controls in the prefrontal, lateral frontal, and parietotemporal cortices, and the cingulate and caudate areas (p< or =0.01, 100 voxel-level). In patients with MSA, hypometabolism was observed in the putamen, pons, and cerebellum in comparison with the healthy controls and IPD patients. CONCLUSION The voxel-based analysis of 18F-FDG PET images showed detailed differences between IPD and MSA, which may be useful in differentiating the two disease entities, as evidenced by the correlation of glucose metabolism with disease severity and dopamine agonist medication. The mapping analysis of 18F-FDG PET images might be a useful adjunctive method of a differential diagnosis for parkinsonism in a clinical setting.

WORKING MEMORY PROCESSING OF FACIAL IMAGES IN SCHIZOPHRENIA: fMRI INVESTIGATION

Impaired processing of facial information is one of the broad ranges of cognitive deficits seen in patients with schizophrenia. This study aimed to elucidate the differences in brain activities involved in the process of facial working memory (images of neutral faces as mnemonic content) between schizophrenic patients and healthy comparison subjects using functional magnetic resonance imaging (fMRI). Group comparison analysis revealed aberrant activities from the patient group in several cortical areas, including the left fusiform gyrus, right superior frontal gyrus, bilateral middle frontal gyri/insula, and left middle temporal gyrus. A decreased level of activity in the left fusiform gyrus, along with performance reduction, implicates abnormal processing of facial information in schizophrenia.

Head motion analysis during cognitive fMRI examination: Application in patients with schizophrenia

OBJECTIVES Functional MRI (fMRI) has become an important imaging modality for analyzing the neural mechanisms underlying schizophrenia. Earlier studies indicate that patients with schizophrenia tend to generate involuntary and unnecessary head motion during visual tasks. Since head motion can deteriorate the quality of fMRI data, an investigation was needed to examine the type and extent of head motion from patients with schizophrenia undergoing fMRI. METHODS Patients with schizophrenia and demographically-matched healthy comparison subjects underwent fMRI examination involving visual working memory tasks. We obtained head movement parameters (three translational and three rotational) through mathematical realignment of the volumetric image data, and transformed these parameters into head displacement indices to quantify the subjects head motion in space. RESULTS We found no group difference in displacement indices between the two groups. Group comparison of movement parameters indicated that the patient group showed reduced head motion along the superior-inferior direction when compared to healthy individuals. CONCLUSION These results suggest that cognitive fMRI examination in patients with schizophrenia can be successfully conducted without the deteriorative effects of head motion.

Verbal Working Memory Dysfunction in Schizophrenia: An fMRI Investigation

Impaired processing of working memory information is one of the cognitive deficits seen in patients with schizophrenia. This study aims at corroborating the differences in the brain activities involved in the process of working memory between patients with schizophrenia and the controls. Twelve patients with schizophrenia and 11 controls participated in the study. Functional magnetic resonance imaging (fMRI) was used to assess cortical activities during the performance of a two-back verbal working memory paradigm using the Korean alphabet as mnemonic content. Group analysis revealed that inferior fontal, middle frontal, and superior temporal region showed decreased cortical activities in the patient group compared to those of the controls. This study showed a decreased activation in inferior fontal (BA 47), middle frontal (BA 6), and superior temporal (BA 22/38) neural networks from the patient group and confirmed the earlier findings on the impaired working memory of schizophrenic patients in the fMRI investigation.

Target-specific rCBF changes induced by 0.3-T static magnetic field exposure on the brain.

The magnetic field has been regarded as both harmful and beneficial for its applications on human brains including transcranial magnetic stimulation (TMS), but its effects still remain in question. Here, we determined using single photon emission computed tomography (SPECT) if 0.3-T static magnetic field could alter regional cerebral blood flow (rCBF) in target and other brain regions in healthy subjects. The permanent static magnet (0.3 T, unipolar, disk shaped, 4 cm diameter and 1 cm thick) was placed on the right frontotemporal region of the brain for each of 14 healthy subjects. Tc-99m ECD perfusion SPECT was taken to compare the CBF patterns in the subjects exposed to the static magnet field with those of the resting and sham conditions. We found that the rCBF was significantly increased in the right frontal and parietal regions and the right insula. On the other hand, rCBF was rather decreased in the left frontal and left parietal regions (P<0.05). These results of this basic study suggest that 0.3-T static magnetic field induces an increase in rCBF in the targeted brain areas non-invasively, which may result from a decrease in rCBF in contralateral regions.

Quantification analysis of 123I‐IPT single photon emission computed tomography uptake in the striatum of parkinsonism with the standard magnetic resonance template

Abstract  This study evaluated the striatal specific binding ratio (SBR), the anterior to posterior ratio of the striatum (APR) and its reproducibility by employing a template‐based registration (TBR) method using the coregistered to the standard T1 magnetic resonance (MR) template (SMRT) as a replacement for the MR image of each patient. The 123I‐IPT single photon emission computed tomography (SPECT) images of 30 patients with Idiopathic Parkinsons disease (IPD) and 11 normal controls were analyzed. The region of interest (ROI) was positioned manually in the same slice showing the highest striatal activity using the manual ROI method, while the ROI were positioned automatically in the mid striatal slice of the SPECT image coregistered to the SMRT. The SBR obtained using the TBR method showed a strong correlation with those using the manual method in all groups: normal controls (r = 0.851, P = 0.001), early IPD (r = 0.841, P < 0.001), and severe IPD (r = 0.702, P = 0.007). The APR obtained by the TBR correlated with those using the manual method in only the early IPD (r = 0.72, P = 0.001), while those obtained using the manual method showed no correlation in the three groups (P > 0.05). The reproducibility (rmsCV) of the TBR method was 7.2% (normal controls, 5.2%; mild IPD, 4.2%; severe IPD, 10.8%), while the reproducibility of the manual method was 31% (normal controls, 19.7%; mild IPD, 21.7%; severe IPD, 46.2%). This shows that the use of 123I‐IPT SPECT for assessing IPD is affected by the method used to position the striatal ROI. This study showed that the TBR method using the SMRT is useful in diagnosing the IPD and assessing the disease severity with a high reproducibility, indicating a possibility of using the TBR method as a good replacement for the manual method.

SU‐E‐I‐73: Gray Matter Atrophy and White Matter Tract Abnormalities by Voxel Wise Correlation Analysis in Patients with Alzheimer's Disease

PURPOSE We evaluated the relationship between white matter (WM) tract disintegration and gray matter (GM) atrophy in patients with Alzheimers disease (AD), mild cognitive impairment (MCI) and controls, using diffusion tensor imaging (DTI) and an optimized voxel-based analysis. METHODS Two hundred thirty one individuals (61 controls, 116 MCI and 54 AD) were included. Voxel-based WM tract statistics was used to obtain whole-brain maps of WM bundles for FA. Voxel-based morphometry (VBM) was conducted to detect regions of gray matter (GM) atrophy in the AD, MCI group relative to the control group. FA maps were processed to make voxel-wise comparison of tract based analysis in whole brain between each the two groups. The relationship between locations of abnormalities in the WM and GM were examined. RESULTS Patients with AD showed significant GM atrophy in posterior cingulate gyrus (BA31, 32) to the precuneus, the middle temporal lobe (BA19), the superior frontal (BA9) to the anterior cingulate (BA 32), the medial frontal lobe (BA 11, BA25), the hippocampus, the parahippocampal gyrus (BA30/34) and the insula, and WM tract disintegrity of the uncinate fasciculus, posterior cingulate fasciculus and fornix compared with the control and MCI groups. These abnormalities in the AD group were caused by either structural changes in GM atrophy or neural dysfunction due to functional disconnections in the WM tract. CONCLUSIONS The GM atrophy resulting from WM tract disintegration or GM atrophy itself may be the first step in the AD process, resulting in anatomically congruent correlations between WM disintegration and regional GM atrophy. Using tract based spatial statistics and voxel based analysis, both of which are useful in investigating GM and WM changes in individuals with neurodegenerative disorders.

SU‐E‐I‐74: White Matter Tract Disintegrate of Frontal and Limbic Regions in Mild Cognitive Impairment with Depression

PURPOSE Mild cognitive impairment with depression (MCID) is common and associated with disability and cognitive impairment, with high probability of relapse. Hypothesize that 1) a sign of WM disintegration would be observed in MCID than MCI nondepression (MCIND), especially in frontal and limbic regions and patients with depression would show reduced GM density in the hippocampus, amygdala, anterior gyrus cingulate, and dorsolateral prefrontal cortex (DLPFC) and dorsomedial prefrontal cortex (DMPFC) 2) the abnormalities of long association fiber tracts integrity are correlated with geriatric depression. METHODS Forty-two subjects (20 nondepressed, 22 depressed) underwent DTI and cognitive assessment. Depression was initially assessed by means of the Korean version of the 30-item Geriatric Depression Scale (K-GDS). All patients scoring 19 or higher on the K-GDS were screened as depressed. An automated tract-based statistical analysis method was used to derive estimates of fractional anisotropy (FA) for each subject. Group effects and correlations with clinical features on DTI parameters were examined. RESULTS We found cross-sectional differences in WM tract disintegration on posterior cingulum, splenium of corpus callosum, uncinate fasciculus, genu, thalamus, internal and external capsule of limbic in MCID. These results support changes in the structural integrity of neuronal cells in these specific important brain regions constituting a fronto-limbic-cerebellar network during depressive and in particular during the course of depression. The different parts of the frontal lobes have afferent and efferent connections with other neocortical, limbic, and subcortical regions and participate in the limbic-cortico-striatal-pallidal-thalamic circuits. CONCLUSIONS Findings are suggestive of loss of integrity in WM fiber within frontal, temporal and limbic regions, increasing the evidence that implicates disruptions to the limbic-orbitofrontal networks in the pathogenesis of MCID. These neuroanatomical circuits play an important role in the regulation and modulation of affect and emotion, and contribute to the pathogenesis of late-life depression.

SU‐E‐J‐77: Tract Based White Matter Abnormalities in Alzheimer Disease with Diffusion Image

Purpose: White matter (WM) damage has been reported in Alzheimers Disease (AD) and Mild Cognitive Impairment (MCI) in diffusiontensorimaging (DTI) studies. DTI provides microstructural information about WM integrity and coherence by measuring fractional anisotropy (FA) values. The aim of this study was to investigate WM abnormalities in AD based on voxel‐wise comparison with controls and to explore their relationship with cortical atrophy and WM integrity detected by voxel based analysis. Methods: Sixty individuals (20 controls, 20 MCI and 20 AD) with age‐matched underwent DTI and volumetric MRI. Voxel‐based tract based spatial‐statistics was used to obtain whole‐brain maps of WM bundles for FA and mean diffusivity(MD). Voxel‐based morphometry was conducted to detect regions of gray matter (GM) atrophy in the AD, MCI group relative to the control group. FA maps were processed to make voxel‐wise comparison of anisotropy in whole brain between each the two groups. The relationship between locations of abnormalities in the WM and GM were examined Results: Significant reductions in FA were found in the WM of both medial temporal lobes, bilateral superior longitudinal fasciculus, bilateral internal capsules, as well as the WM of left middle temporal gyrus and right superior parietal lobule, the body and genu of the corpus callosum, cingulum, and the uncinate, superior longitudical fasciculus in patients with AD. Although the decrease in FA was consistent with cortical volumetric reduction in both temporal lobes, the widespread involvement of superior longitudinal fasciculus and uncinate fasciculus was dominant in these WM findings. Conclusions: Voxel‐wise comparison of whole‐brain anisotropy revealed widely distributed disintegration of WM in AD. The WM shows a different pattern of degeneration from GM and may be an independent factor in the progress of AD. These results suggest that DTI analysis of WM structural integrity can serve as potential biomarkers of AD progression.