- Email: [email protected]
Distinctive resting state network disruptions among Alzheimer’s disease, subcortical vascular dementia, and mixed dementia patients
P412
Poster Presentations: P1
patients and care plan altered in 22 patients). A positive PET scan resulted in change of management plans (either medication, care, or both) nine times more often than a negative PET scan (n¼61 vs. n¼7; p<0.001). For 43 (22%) patients, additional ancillary investigations were planned after PET results were disclosed, predominantly when PET results were negative (n¼33; p<0.001). In patients with a pre-PET AD diagnosis and a positive PET scan, additional ancillary investigations were less often requested compared to patients with a negative PET scan (p<0.001). Conclusions: [18F]Flutemetamol PET increased physician’s overall confidence in clinical diagnosis. In addition, it altered diagnostic work-up and healthcare management plan of young onset dementia patients visiting a tertiary memory clinic.
P1-175
DIFFUSION TENSOR METRICS AS BIOMARKERS IN IDIOPATHIC NORMAL-PRESSURE HYDROCEPHALUS
Kyunghun Kang1, Dongho Choi1, Pan-Woo Ko1, Ho-Won Lee1, Uicheul Yoon2, 1School of Medicine, Kyungpook National University, Daegu, South Korea; 2College of Health and Medical Science, Catholic University of Daegu, Gyeongsan-si, South Korea. Contact e-mail: [email protected] Background: Diffusion tensor imaging (DTI) is sensitive to microstructural changes in white matter not always detectable with ordinary magnetic resonance imaging. We evaluated relationships between DTI parameters and clinical profiles in idiopathic normal-pressure hydrocephalus (INPH) patients, along with differences in these DTI measures between CSF tap test (CSFTT) responders and non-responders. Methods: Fifty-four INPH patients (26 CSFTT responders and 28 CSFTT non-responders) constituted the final group for analysis. Fractional anisotropy (FA) and mean diffusivity (MD) were assessed using atlas-based tract-mapping methods on 12 different fiber tracts. Results: CSFTT non-responders, when compared to responders, showed lower FA values in the left anterior thalamic radiation (ATR), left cingulum–hippocampus (CgH), and forceps major and higher MD values in the left CgH. DTI parameters in the ATR and corticospinal tract (CST) largely correlated with motor function, whereas DTI parameters in the CgH mainly correlated with global cognitive performance. Lower FA in the right and left ATR and right CST correlated with motor dysfunction. Higher MD in the right and left CST correlated with motor dysfunction. Lower FA in the right CgH correlated with poorer cognitive performance. Higher MD values for the right and left CgH correlated poorer cognitive performance. Conclusions: Our findings may suggest a possibility for considering microstructural changes of white matter in patients with ventriculomegaly as potential imaging markers for the prediction of CSFTT responders. Despite some overlap, unique patterns of white matter microstructural changes, as measured using DTI, might underlie impairments in distinct symptom domains in patients with INPH.
P1-176
DISTINCTIVE RESTING STATE NETWORK DISRUPTIONS AMONG ALZHEIMER’S DISEASE, SUBCORTICAL VASCULAR DEMENTIA, AND MIXED DEMENTIA PATIENTS
Hee Jin Kim1, Jungho Cha2, Jong Min Lee2, Ji Soo Shin1, Na Yeon Jung1, Yeo Jin Kim1, Yearn Seong Cheo1, Kyung Han Lee1, Sung Tae Kim1, Jae Seoung Kim1, Jae-Hong Lee3, Duk L. Na1, Sang Won Seo4, 1Samsung
Medical Center, Seoul, South Korea; 2Hanyang University, Seoul, South Korea; 3Asan Medical Center, Seoul, South Korea; 4University of California San Francisco, San Francisco, CA, USA. Contact e-mail: [email protected] Background: Recent advances in resting state functional MRI have revealed altered functional networks in Alzheimer’s disease (AD), especially that of the default mode network (DMN) and central executive network (CEN). However, few studies have evaluated whether small vessel disease (SVD) or combined amyloid and SVD burdens affect the DMN or CEN. Methods: We investigated the resting state DMN and CEN connectivities in 39 Pittsburg compound-B (PiB)+AD (pure AD), 33 PiB- subcortical vascular dementia (pure SVaD), 17 PiB+SVaD (mixed dementia) patients, and 64 normal controls. Results: Compared to pure SVaD, pure AD patients showed decreased DMN connectivity in the left inferior parietal lobule and increased connectivity in the right medial frontal and left syperior frontal gyri. Compared to pure SVaD or pure AD, mixed dementia patients showed decreased DMN connectivity in the right posterior cingulate gyrus, and in the left posterior cingulate and left superior frontal gyri, respectively. Compared to pure AD, pure SVaD patients showed decreased CEN connectivity in the left insula regions. Compared to pure SVaD or pure AD, mixed dementia patients showed decreased CEN connectivity in the left inferior frontal gyrus. Conclusions: Our findings suggest that in pure AD and pure SVaD, there is divergent disruptions in resting state DMN and CEN connectivity. Furthermore, patients with combined amyloid and SVD burdens had more disrupted resting state DMN and CEN connectivity than patients with only amyloid or SVD burden.
P1-177
EXTENSIVE WHITE MATTER BURDEN REPRESENTS A NEW RADIOLOGICAL PHENOTYPE IN A DISTINCT POPULATION OF AD PATIENTS
Paolo Vitali1,2, Serge Gauthier3, Tom Beaudry2, Jean-Paul Soucy1,4,5, Simona M. Brambati1,6, Pedro Rosa-Neto7, 1Universite de Montreal, Montreal, QC, Canada; 2McGill Centre for Studies in Aging, Montreal, QC, Canada; 3McGill Centre for Studies in Aging, Montreal, QC, Canada; 4 McGill University, Montreal, QC, Canada; 5McConnell Brain Imaging Centre, Montreal, QC, Canada; 6Centre de Recherche de l’Institut Universitaire de Geriatrie de Montreal, Montreal, QC, Canada; 7Centre for Studies on Prevention of Alzheimer’s Disease (StoP-AD Centre), Douglas Mental Health Institute, Montreal, QC, Canada. Contact e-mail: pedro. [email protected] Background: Previous neuropathological observations and neuroi-
maging studies in pathologically-proven non-AD dementias showed that tauopathies have characteristic tau inclusions throughout white matter (WM) brain regions, with relative sparing of grey matter (GM). However, the association between surrogate CSF markers of tau-induced neurodegeneration and WM structural changes in patients with Alzheimer’s disease (AD) remains overlooked. In this study, we compared clinically-defined AD patients with and without CSF evidence of tau neurodegeneration, in order to radiologically characterize tau-dependent neurodegenerative processes in AD. Methods: Data were obtained from the ADNI (Alzheimer’s Disease Neuroimaging Initiative) database (adni.loni.usc. edu) on all individuals with a baseline diagnosis of AD or normal control (CN), baseline T1-weighted brain MRI and CSF biomarkers. For the AD group, only patients with CSF amyloid-b142levels below the 192 pg/mL threshold (suggestive of significant cerebral amyloidopathy) were retained for further analyses. Selected AD patients were dichotomized using previously
Poster Presentations: P1
patients and care plan altered in 22 patients). A positive PET scan resulted in change of management plans (either medication, care, or both) nine times more often than a negative PET scan (n¼61 vs. n¼7; p<0.001). For 43 (22%) patients, additional ancillary investigations were planned after PET results were disclosed, predominantly when PET results were negative (n¼33; p<0.001). In patients with a pre-PET AD diagnosis and a positive PET scan, additional ancillary investigations were less often requested compared to patients with a negative PET scan (p<0.001). Conclusions: [18F]Flutemetamol PET increased physician’s overall confidence in clinical diagnosis. In addition, it altered diagnostic work-up and healthcare management plan of young onset dementia patients visiting a tertiary memory clinic.
P1-175
DIFFUSION TENSOR METRICS AS BIOMARKERS IN IDIOPATHIC NORMAL-PRESSURE HYDROCEPHALUS
Kyunghun Kang1, Dongho Choi1, Pan-Woo Ko1, Ho-Won Lee1, Uicheul Yoon2, 1School of Medicine, Kyungpook National University, Daegu, South Korea; 2College of Health and Medical Science, Catholic University of Daegu, Gyeongsan-si, South Korea. Contact e-mail: [email protected] Background: Diffusion tensor imaging (DTI) is sensitive to microstructural changes in white matter not always detectable with ordinary magnetic resonance imaging. We evaluated relationships between DTI parameters and clinical profiles in idiopathic normal-pressure hydrocephalus (INPH) patients, along with differences in these DTI measures between CSF tap test (CSFTT) responders and non-responders. Methods: Fifty-four INPH patients (26 CSFTT responders and 28 CSFTT non-responders) constituted the final group for analysis. Fractional anisotropy (FA) and mean diffusivity (MD) were assessed using atlas-based tract-mapping methods on 12 different fiber tracts. Results: CSFTT non-responders, when compared to responders, showed lower FA values in the left anterior thalamic radiation (ATR), left cingulum–hippocampus (CgH), and forceps major and higher MD values in the left CgH. DTI parameters in the ATR and corticospinal tract (CST) largely correlated with motor function, whereas DTI parameters in the CgH mainly correlated with global cognitive performance. Lower FA in the right and left ATR and right CST correlated with motor dysfunction. Higher MD in the right and left CST correlated with motor dysfunction. Lower FA in the right CgH correlated with poorer cognitive performance. Higher MD values for the right and left CgH correlated poorer cognitive performance. Conclusions: Our findings may suggest a possibility for considering microstructural changes of white matter in patients with ventriculomegaly as potential imaging markers for the prediction of CSFTT responders. Despite some overlap, unique patterns of white matter microstructural changes, as measured using DTI, might underlie impairments in distinct symptom domains in patients with INPH.
P1-176
DISTINCTIVE RESTING STATE NETWORK DISRUPTIONS AMONG ALZHEIMER’S DISEASE, SUBCORTICAL VASCULAR DEMENTIA, AND MIXED DEMENTIA PATIENTS
Hee Jin Kim1, Jungho Cha2, Jong Min Lee2, Ji Soo Shin1, Na Yeon Jung1, Yeo Jin Kim1, Yearn Seong Cheo1, Kyung Han Lee1, Sung Tae Kim1, Jae Seoung Kim1, Jae-Hong Lee3, Duk L. Na1, Sang Won Seo4, 1Samsung
Medical Center, Seoul, South Korea; 2Hanyang University, Seoul, South Korea; 3Asan Medical Center, Seoul, South Korea; 4University of California San Francisco, San Francisco, CA, USA. Contact e-mail: [email protected] Background: Recent advances in resting state functional MRI have revealed altered functional networks in Alzheimer’s disease (AD), especially that of the default mode network (DMN) and central executive network (CEN). However, few studies have evaluated whether small vessel disease (SVD) or combined amyloid and SVD burdens affect the DMN or CEN. Methods: We investigated the resting state DMN and CEN connectivities in 39 Pittsburg compound-B (PiB)+AD (pure AD), 33 PiB- subcortical vascular dementia (pure SVaD), 17 PiB+SVaD (mixed dementia) patients, and 64 normal controls. Results: Compared to pure SVaD, pure AD patients showed decreased DMN connectivity in the left inferior parietal lobule and increased connectivity in the right medial frontal and left syperior frontal gyri. Compared to pure SVaD or pure AD, mixed dementia patients showed decreased DMN connectivity in the right posterior cingulate gyrus, and in the left posterior cingulate and left superior frontal gyri, respectively. Compared to pure AD, pure SVaD patients showed decreased CEN connectivity in the left insula regions. Compared to pure SVaD or pure AD, mixed dementia patients showed decreased CEN connectivity in the left inferior frontal gyrus. Conclusions: Our findings suggest that in pure AD and pure SVaD, there is divergent disruptions in resting state DMN and CEN connectivity. Furthermore, patients with combined amyloid and SVD burdens had more disrupted resting state DMN and CEN connectivity than patients with only amyloid or SVD burden.
P1-177
EXTENSIVE WHITE MATTER BURDEN REPRESENTS A NEW RADIOLOGICAL PHENOTYPE IN A DISTINCT POPULATION OF AD PATIENTS
Paolo Vitali1,2, Serge Gauthier3, Tom Beaudry2, Jean-Paul Soucy1,4,5, Simona M. Brambati1,6, Pedro Rosa-Neto7, 1Universite de Montreal, Montreal, QC, Canada; 2McGill Centre for Studies in Aging, Montreal, QC, Canada; 3McGill Centre for Studies in Aging, Montreal, QC, Canada; 4 McGill University, Montreal, QC, Canada; 5McConnell Brain Imaging Centre, Montreal, QC, Canada; 6Centre de Recherche de l’Institut Universitaire de Geriatrie de Montreal, Montreal, QC, Canada; 7Centre for Studies on Prevention of Alzheimer’s Disease (StoP-AD Centre), Douglas Mental Health Institute, Montreal, QC, Canada. Contact e-mail: pedro. [email protected] Background: Previous neuropathological observations and neuroi-
maging studies in pathologically-proven non-AD dementias showed that tauopathies have characteristic tau inclusions throughout white matter (WM) brain regions, with relative sparing of grey matter (GM). However, the association between surrogate CSF markers of tau-induced neurodegeneration and WM structural changes in patients with Alzheimer’s disease (AD) remains overlooked. In this study, we compared clinically-defined AD patients with and without CSF evidence of tau neurodegeneration, in order to radiologically characterize tau-dependent neurodegenerative processes in AD. Methods: Data were obtained from the ADNI (Alzheimer’s Disease Neuroimaging Initiative) database (adni.loni.usc. edu) on all individuals with a baseline diagnosis of AD or normal control (CN), baseline T1-weighted brain MRI and CSF biomarkers. For the AD group, only patients with CSF amyloid-b142levels below the 192 pg/mL threshold (suggestive of significant cerebral amyloidopathy) were retained for further analyses. Selected AD patients were dichotomized using previously