- Email: [email protected]
Diffusion tensor tractography of white matter tracts within the temporal stem in Alzhiemer disease on 3 tesla MRI
Poster Presentations P3 P3-084
BRAIN ATROPHY PATTERNS IN LATE-ONSET DEPRESSION AND MILD COGNITIVE IMPAIRMENT
Na Zhang1,2, Mei-Yan Zhang1,2, Kevin Head3, Daniel Chang3, Huishu Yuan4, Min-Ying Su3, Xin Yu1,2, Huali Wang1,2, 1Peking University Institute of Mental Health, Beijing, China; 2Key Laboratory for Mental Health, Ministry of Health, Beijing, China; 3University of California, Irvine, CA, USA; 4Department of Radiology, Peking University Third Hospital, Beijing, China. Contact e-mail: [email protected] Background: Cognitive impairment and late-life depression are associated with increased risk for subsequent dementia. Depressive symptomatology independently predicts cognitive decline and incident cognitive impairment in older persons. This study aimed to investigate the cerebral atrophy pattern in cognitive impairment associated with late-onset depression and to preliminary examine whether there are common or distinct mechanisms involved in the associations between depression and mild cognitive impairment. Methods: Nine patients with late-onset depression (ICD-10 criteria, LOD group, age¼64.969.2, male¼4, female¼5, MMSE¼22.765.5), fourteen subjects meeting aMCI criteria proposed by Petersen (aMCI group, age¼72.664.9, male¼8, female¼6, MMSE¼26.061.9), and 16 healthy elderly controls (NC group, age¼69.962.8, male¼6, female¼10, MMSE¼28.662.6) with normal-appearing white matter were enrolled in this prospective study. All subjects underwent a comprehensive neuropsychological test and MRI scanning when recruited into DCRC case registry. High-resolution 3D T1 structural images were acquired with 3D-MPRAGE sequence (TR¼2530ms,TE¼3.44ms,TI¼1100ms,slice thickness¼1 mm with no gap,FOV¼2563256,voxel size¼1 mm31 mm31 mm). All 3D T1 images were analyzed with SPM5 by following the procedures of optimized voxel-based morphometry (VBM). Age and gender were used as nuisance variables in the analysis. Results: Compared with control group, there was significant gray matter atrophy in bilateral superior frontal gyri, left precuneus and inferior parietal lobule, and right inferior occipital gyri, middle occipital gyri, uncus and rectal gyri in LOD group (Puncorrected<0.005, Figure 1). When relative to aMCI group, LOD group showed significant atrophy in bilateral superior, medial and middle frontal gyri, left postcentral gyri, paracentral gyri, inferior parietal lobule, inferior occipital gyri, precuneus, and right uncus, cingulate gyri, inferior frontal gysi, and parahippocampal gyrus (Puncorrected<0.005, Figure 1). No suprathreshold clusters in LOD group were identified greater than either aMCI or NC group. Conclusions: Cognitive impairment associated with late-onset depression presents more severe and pervasive brain atrophy, especially in frontal lobe than aMCI. It is suggested that during the progression from depression to cognitive impairment, frontal-occipital circuit may play an important role. Further longitudinal investigations integrating multi-modality imaging techniques are warranted.
Fig. 1. Statistical maps of brain atrophy in cognitive impairment associated with late-onset depression (LOD) relative to normal control (NC, left) and amnestic mild cognitive impairment (aMCI, right) at significance level of Puncorrected<0.005. P3-085
ANALYSIS OF MEMORY IN AN AGING POPULATION: INTERACTION OF HIPPOCAMPAL STRUCTURE AND FUNCTION
Christiane Reitz1, Adam Brickman1, Truman Brown1, Jennifer Manly1, Charles DeCarli2, Scott Small1, Richard Mayeux1, 1Columbia University,
P367
New York, NY, USA; 2University of California, Sacramento, CA, USA. Contact e-mail: [email protected] Background: Magnetic resonance imaging (MRI) can assess both structure and function of the hippocampal formation. We tested the hypothesis that in Alzheimer’s disease cellular dysfunction measured by blood flow precedes cell death measured by atrophy. Methods: Regression analyses were used to relate main effects and interactions of entorhinal cortex (EC) cerebral blood volume (EC-CBV), EC volume, hippocampus volume and hippocampus-CBV with measures of memory performance in 231 elderly persons. Results: There was no association between EC-volume or hippocampus-CBV and memory. Increased hippocampus volume was strongly associated with better long-term recall and delayed recognition. Higher EC-CBV was significantly associated with better delayed recall, and a significant interaction was found between hippocampus volume and EC-CBV on long-term recall and delayed recall. Excluding demented persons, all associations of EC-CBV with memory measures remained significant while the associations between hippocampus volume and memory became non-significant as did the interactions of hippocampus volume and EC-CBV on delayed recall. Conclusions: Tissue loss characterized by hippocampal atrophy and cell dysfunction typified by changes in EC-CBV interact in their effect on memory. Metabolic rather than structural changes contribute to memory dysfunction early, while in later stages of disease both structural and functional effects play a role.
P3-086
DIFFUSION TENSOR TRACTOGRAPHY OF WHITE MATTER TRACTS WITHIN THE TEMPORAL STEM IN ALZHIEMER DISEASE ON 3 TESLA MRI
Rima Kumari, Suman Khushwaha, Rohit Gupta, D. C. Jain, IHBAS, DELHI, India. Contact e-mail: [email protected] Background: The temporal stem which is a white matter region bridging the frontal and temporal lobes contains several white matter tracts, including the anterior commissure, uncinate fasciculus, inferior occipitofrontal fasciculus, and Meyer’s loop of the optic tract. Alzhiemer disease (AD) is associated with microstructural changes in the white matter of temporal stem causing increased diffusivity and decreased diffusion anisotropy. Our purpose was to delineate individual tracts within the temporal stem and measure fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the tracts. To the best of our knowledge, no study has so far reported these findings using high field diffusion tensor tractoraphy. Methods: Twelve patients with AD and twelve age-matched control subjects were scanned on a 3 Tesla MR scanner. Diffusion tensor images were acquired using a single shot echo planar imaging sequence with diffusion encoding in 32 directions and a voxel size of 2x2x2 mm3. We obtained tractographies of the anterior commissure, inferior occipitofrontal fasciculus, uncinate fasciculus and Meyer’s loop using the diffusion tensor analysis software (Functool). The diffusion indices (ADC, FA values) were measured and student t test was used for comparison of the results between patients with AD and control subjects. Results: The ADC values of bilateral Meyer’s loop, inferior occipitofrontal and uncinate fasciculi were significantly higher for patients with AD than for controls. The FA values of these tracts were significantly lower for AD patients than for controls. There was no significant difference in ADC and FA values of anterior commissure between the two groups. Tractography images rotated in different planes were able to depict thinning with reduced fiber density of the uncinate and inferior occipitofrontal fasciculi in AD patients as compared with controls. Conclusions: Diffusion tensor tractography on high field MRI can depict individual white matter tracts within the temporal stem. This method can provide tract - specific information on anisotropy and diffusivity and is a promising technique for early diagnosis of neurodegenerative diseases such as AD.
BRAIN ATROPHY PATTERNS IN LATE-ONSET DEPRESSION AND MILD COGNITIVE IMPAIRMENT
Na Zhang1,2, Mei-Yan Zhang1,2, Kevin Head3, Daniel Chang3, Huishu Yuan4, Min-Ying Su3, Xin Yu1,2, Huali Wang1,2, 1Peking University Institute of Mental Health, Beijing, China; 2Key Laboratory for Mental Health, Ministry of Health, Beijing, China; 3University of California, Irvine, CA, USA; 4Department of Radiology, Peking University Third Hospital, Beijing, China. Contact e-mail: [email protected] Background: Cognitive impairment and late-life depression are associated with increased risk for subsequent dementia. Depressive symptomatology independently predicts cognitive decline and incident cognitive impairment in older persons. This study aimed to investigate the cerebral atrophy pattern in cognitive impairment associated with late-onset depression and to preliminary examine whether there are common or distinct mechanisms involved in the associations between depression and mild cognitive impairment. Methods: Nine patients with late-onset depression (ICD-10 criteria, LOD group, age¼64.969.2, male¼4, female¼5, MMSE¼22.765.5), fourteen subjects meeting aMCI criteria proposed by Petersen (aMCI group, age¼72.664.9, male¼8, female¼6, MMSE¼26.061.9), and 16 healthy elderly controls (NC group, age¼69.962.8, male¼6, female¼10, MMSE¼28.662.6) with normal-appearing white matter were enrolled in this prospective study. All subjects underwent a comprehensive neuropsychological test and MRI scanning when recruited into DCRC case registry. High-resolution 3D T1 structural images were acquired with 3D-MPRAGE sequence (TR¼2530ms,TE¼3.44ms,TI¼1100ms,slice thickness¼1 mm with no gap,FOV¼2563256,voxel size¼1 mm31 mm31 mm). All 3D T1 images were analyzed with SPM5 by following the procedures of optimized voxel-based morphometry (VBM). Age and gender were used as nuisance variables in the analysis. Results: Compared with control group, there was significant gray matter atrophy in bilateral superior frontal gyri, left precuneus and inferior parietal lobule, and right inferior occipital gyri, middle occipital gyri, uncus and rectal gyri in LOD group (Puncorrected<0.005, Figure 1). When relative to aMCI group, LOD group showed significant atrophy in bilateral superior, medial and middle frontal gyri, left postcentral gyri, paracentral gyri, inferior parietal lobule, inferior occipital gyri, precuneus, and right uncus, cingulate gyri, inferior frontal gysi, and parahippocampal gyrus (Puncorrected<0.005, Figure 1). No suprathreshold clusters in LOD group were identified greater than either aMCI or NC group. Conclusions: Cognitive impairment associated with late-onset depression presents more severe and pervasive brain atrophy, especially in frontal lobe than aMCI. It is suggested that during the progression from depression to cognitive impairment, frontal-occipital circuit may play an important role. Further longitudinal investigations integrating multi-modality imaging techniques are warranted.
Fig. 1. Statistical maps of brain atrophy in cognitive impairment associated with late-onset depression (LOD) relative to normal control (NC, left) and amnestic mild cognitive impairment (aMCI, right) at significance level of Puncorrected<0.005. P3-085
ANALYSIS OF MEMORY IN AN AGING POPULATION: INTERACTION OF HIPPOCAMPAL STRUCTURE AND FUNCTION
Christiane Reitz1, Adam Brickman1, Truman Brown1, Jennifer Manly1, Charles DeCarli2, Scott Small1, Richard Mayeux1, 1Columbia University,
P367
New York, NY, USA; 2University of California, Sacramento, CA, USA. Contact e-mail: [email protected] Background: Magnetic resonance imaging (MRI) can assess both structure and function of the hippocampal formation. We tested the hypothesis that in Alzheimer’s disease cellular dysfunction measured by blood flow precedes cell death measured by atrophy. Methods: Regression analyses were used to relate main effects and interactions of entorhinal cortex (EC) cerebral blood volume (EC-CBV), EC volume, hippocampus volume and hippocampus-CBV with measures of memory performance in 231 elderly persons. Results: There was no association between EC-volume or hippocampus-CBV and memory. Increased hippocampus volume was strongly associated with better long-term recall and delayed recognition. Higher EC-CBV was significantly associated with better delayed recall, and a significant interaction was found between hippocampus volume and EC-CBV on long-term recall and delayed recall. Excluding demented persons, all associations of EC-CBV with memory measures remained significant while the associations between hippocampus volume and memory became non-significant as did the interactions of hippocampus volume and EC-CBV on delayed recall. Conclusions: Tissue loss characterized by hippocampal atrophy and cell dysfunction typified by changes in EC-CBV interact in their effect on memory. Metabolic rather than structural changes contribute to memory dysfunction early, while in later stages of disease both structural and functional effects play a role.
P3-086
DIFFUSION TENSOR TRACTOGRAPHY OF WHITE MATTER TRACTS WITHIN THE TEMPORAL STEM IN ALZHIEMER DISEASE ON 3 TESLA MRI
Rima Kumari, Suman Khushwaha, Rohit Gupta, D. C. Jain, IHBAS, DELHI, India. Contact e-mail: [email protected] Background: The temporal stem which is a white matter region bridging the frontal and temporal lobes contains several white matter tracts, including the anterior commissure, uncinate fasciculus, inferior occipitofrontal fasciculus, and Meyer’s loop of the optic tract. Alzhiemer disease (AD) is associated with microstructural changes in the white matter of temporal stem causing increased diffusivity and decreased diffusion anisotropy. Our purpose was to delineate individual tracts within the temporal stem and measure fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the tracts. To the best of our knowledge, no study has so far reported these findings using high field diffusion tensor tractoraphy. Methods: Twelve patients with AD and twelve age-matched control subjects were scanned on a 3 Tesla MR scanner. Diffusion tensor images were acquired using a single shot echo planar imaging sequence with diffusion encoding in 32 directions and a voxel size of 2x2x2 mm3. We obtained tractographies of the anterior commissure, inferior occipitofrontal fasciculus, uncinate fasciculus and Meyer’s loop using the diffusion tensor analysis software (Functool). The diffusion indices (ADC, FA values) were measured and student t test was used for comparison of the results between patients with AD and control subjects. Results: The ADC values of bilateral Meyer’s loop, inferior occipitofrontal and uncinate fasciculi were significantly higher for patients with AD than for controls. The FA values of these tracts were significantly lower for AD patients than for controls. There was no significant difference in ADC and FA values of anterior commissure between the two groups. Tractography images rotated in different planes were able to depict thinning with reduced fiber density of the uncinate and inferior occipitofrontal fasciculi in AD patients as compared with controls. Conclusions: Diffusion tensor tractography on high field MRI can depict individual white matter tracts within the temporal stem. This method can provide tract - specific information on anisotropy and diffusivity and is a promising technique for early diagnosis of neurodegenerative diseases such as AD.