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Hippocampal microstructure and memory performance in Alzheimer's disease: A 7-Tesla MRI study
Poster Presentations P4
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of the hippocampus, the hippocampal strata are visible, including the stratum pyramidale (SP) and stratum radiatum / lacunosum-moleculare (SRLM). In prior work (Kerchner et al., 2010, Neurology 75:13811387), atrophy of the SRLM was evident in patients with mild Alzheimer’s disease (AD) relative to age-matched normal controls. In that study, manual measurements were made of stratal width. We endeavored to create a semi-automated method for measuring stratal width, and to test the resulting method on the prior data set. Methods: On raw oblique coronal 7-Tesla images oriented perpendicular to the hippocampal body, a line was drawn by the user along the center of the SRLM, and another line was drawn along the center of the SP. We wrote a MATLAB script that examined each user-specified line as follows: Normal vectors were drawn at multiple points along each line, and intensity values along those vectors were plotted against the relative distance from the user-specified line. These plots were averaged to yield a curve with a negative peak (for SRLM) or positive peak (for SP). The distance between the positive and negative peaks of the first derivative of that curve was used as the measure of stratal width. This procedure was applied to the T2*weighted 7-Tesla GRE images in the prior publication. Four subjects were excluded, because of incompatibilities of their original data with the new procedure. Results: The semi-automated measurements of SRLM and SP thickness worked robustly, correlating significantly with the manual measurements (SP: r ¼ 0.71, p < 0.001; SRLM: r ¼ 0.45, p ¼ 0.001). As in the prior study, the SRLM was significantly thinner among patients with AD (590 6 80 micro-m, using the new method; n ¼ 13) versus normal controls (670 6 110 micro-m; n ¼ 13; p < 0.05). Additionally, SP was significantly thinner among AD patients (1.2 6 0.4 mm) versus normal controls (1.5 6 0.2 mm; p < 0.05). Conclusions: In sum, we present a semi-automated method for extracting SP and SRLM thicknesses from 7-Tesla hippocampal cross-sectional images and demonstrate its use in revealing microanatomical features of AD.
P4-059
HIPPOCAMPAL MICROSTRUCTURE AND MEMORY PERFORMANCE IN ALZHEIMER’S DISEASE: A 7-TESLA MRI STUDY
Geoffrey Kerchner1, Gayle Deutsch1, Michael Zeineh1, Brian Rutt1, 1 Stanford University, Stanford, California, United States. Background: The hippocampus is one of the earliest brain structures affected by pathological change in Alzheimer’s disease (AD). A prior study revealed the ability of ultra-high field 7-Tesla MRI to detect microstructural changes in hippocampal cross-sectional anatomy in patients with AD (Kerchner et al., 2010, Neurology 75:1381-1387). Here, we used this imaging modality to study whether microstructural features of the hippocampus correlate with memory performance. Methods: We recruited 5 patients with probable AD (aged 66 6 7 years; MMSE 23 6 2; CDR 0.5-1)from the Stanford Center for Memory Disorders for this cross-sectional study. Each subject underwent a neuropsychological assessment that included, among other tests, the Hopkins Verbal Learning Test-Revised (HVLT), the Brief Visuospatial Memory Test-Revised (BVMT), and the Logical Memory component of the Wechsler Memory Scale-III (LM). Each subject also underwent 7-Tesla MRI, which included a two-dimensional fast spin echo (FSE) sequence with a resolution of 0.22x0.22x1.5 mm, acquired in an oblique coronal plane oriented longitudinally to the body of the hippocampus. The thicknesses of the CA1 stratum pyramidale (SP) and stratum radiatum / lacunosum-moleculare (SRLM) were measured using a semi-automated technique (see Kerchner and Dougherty, ICAD 2011), and the cross-sectional area of the dentate gyrus / CA3 (DG) was measured manually on each slice (Figure). Results: On the HVLT and BVMT, performance on a discrimination index (hits minus false positives on the cued recognition task performed after the long-delay recall trial) correlated closely with SP thickness (HVLT: r ¼ 0.97, p < 0.01; BVMT: r ¼ 0.94, p < 0.05) but not DG area (Figure). By contrast, immediate recall on the LM test correlated closely with DG area (r ¼ 0.95, p < 0.05) but not SP or SRLM thicknesses
(Figure). None of these hippocampal microstructural metrics correlated with age or with performance on a working memory test (digit span), full-scale IQ, or other tests of visuospatial, language, or executive function. Conclusions: Among these patients with mild AD, microstructural features of the hippocampus, as assessed by a 7-Tesla FSE MRI sequence, were specifically predictive of memory performance. These data highlight a role for 7-Tesla MRI in the study of hippocampal microstructure and its functional correlations.
P4-060
18F-SNUBH-NM-333 AS A POTENTIAL PROBE FOR PET IMAGING OF AMYLOID PLAQUES
Sang Eun Kim1, Byung Chul Lee1, Ji Sun Kim1, Jae Ho Jung1, Byung Seok Moon1, IL Han Choo2, Jae Sung Lee2, Hyun Soo Park1, Ji Yeon Son1, In Soon Jung1, Yu Kyeong Kim1, Dong Young Lee2, Jong Inn Woo2, 1Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea; 2Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea.
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of the hippocampus, the hippocampal strata are visible, including the stratum pyramidale (SP) and stratum radiatum / lacunosum-moleculare (SRLM). In prior work (Kerchner et al., 2010, Neurology 75:13811387), atrophy of the SRLM was evident in patients with mild Alzheimer’s disease (AD) relative to age-matched normal controls. In that study, manual measurements were made of stratal width. We endeavored to create a semi-automated method for measuring stratal width, and to test the resulting method on the prior data set. Methods: On raw oblique coronal 7-Tesla images oriented perpendicular to the hippocampal body, a line was drawn by the user along the center of the SRLM, and another line was drawn along the center of the SP. We wrote a MATLAB script that examined each user-specified line as follows: Normal vectors were drawn at multiple points along each line, and intensity values along those vectors were plotted against the relative distance from the user-specified line. These plots were averaged to yield a curve with a negative peak (for SRLM) or positive peak (for SP). The distance between the positive and negative peaks of the first derivative of that curve was used as the measure of stratal width. This procedure was applied to the T2*weighted 7-Tesla GRE images in the prior publication. Four subjects were excluded, because of incompatibilities of their original data with the new procedure. Results: The semi-automated measurements of SRLM and SP thickness worked robustly, correlating significantly with the manual measurements (SP: r ¼ 0.71, p < 0.001; SRLM: r ¼ 0.45, p ¼ 0.001). As in the prior study, the SRLM was significantly thinner among patients with AD (590 6 80 micro-m, using the new method; n ¼ 13) versus normal controls (670 6 110 micro-m; n ¼ 13; p < 0.05). Additionally, SP was significantly thinner among AD patients (1.2 6 0.4 mm) versus normal controls (1.5 6 0.2 mm; p < 0.05). Conclusions: In sum, we present a semi-automated method for extracting SP and SRLM thicknesses from 7-Tesla hippocampal cross-sectional images and demonstrate its use in revealing microanatomical features of AD.
P4-059
HIPPOCAMPAL MICROSTRUCTURE AND MEMORY PERFORMANCE IN ALZHEIMER’S DISEASE: A 7-TESLA MRI STUDY
Geoffrey Kerchner1, Gayle Deutsch1, Michael Zeineh1, Brian Rutt1, 1 Stanford University, Stanford, California, United States. Background: The hippocampus is one of the earliest brain structures affected by pathological change in Alzheimer’s disease (AD). A prior study revealed the ability of ultra-high field 7-Tesla MRI to detect microstructural changes in hippocampal cross-sectional anatomy in patients with AD (Kerchner et al., 2010, Neurology 75:1381-1387). Here, we used this imaging modality to study whether microstructural features of the hippocampus correlate with memory performance. Methods: We recruited 5 patients with probable AD (aged 66 6 7 years; MMSE 23 6 2; CDR 0.5-1)from the Stanford Center for Memory Disorders for this cross-sectional study. Each subject underwent a neuropsychological assessment that included, among other tests, the Hopkins Verbal Learning Test-Revised (HVLT), the Brief Visuospatial Memory Test-Revised (BVMT), and the Logical Memory component of the Wechsler Memory Scale-III (LM). Each subject also underwent 7-Tesla MRI, which included a two-dimensional fast spin echo (FSE) sequence with a resolution of 0.22x0.22x1.5 mm, acquired in an oblique coronal plane oriented longitudinally to the body of the hippocampus. The thicknesses of the CA1 stratum pyramidale (SP) and stratum radiatum / lacunosum-moleculare (SRLM) were measured using a semi-automated technique (see Kerchner and Dougherty, ICAD 2011), and the cross-sectional area of the dentate gyrus / CA3 (DG) was measured manually on each slice (Figure). Results: On the HVLT and BVMT, performance on a discrimination index (hits minus false positives on the cued recognition task performed after the long-delay recall trial) correlated closely with SP thickness (HVLT: r ¼ 0.97, p < 0.01; BVMT: r ¼ 0.94, p < 0.05) but not DG area (Figure). By contrast, immediate recall on the LM test correlated closely with DG area (r ¼ 0.95, p < 0.05) but not SP or SRLM thicknesses
(Figure). None of these hippocampal microstructural metrics correlated with age or with performance on a working memory test (digit span), full-scale IQ, or other tests of visuospatial, language, or executive function. Conclusions: Among these patients with mild AD, microstructural features of the hippocampus, as assessed by a 7-Tesla FSE MRI sequence, were specifically predictive of memory performance. These data highlight a role for 7-Tesla MRI in the study of hippocampal microstructure and its functional correlations.
P4-060
18F-SNUBH-NM-333 AS A POTENTIAL PROBE FOR PET IMAGING OF AMYLOID PLAQUES
Sang Eun Kim1, Byung Chul Lee1, Ji Sun Kim1, Jae Ho Jung1, Byung Seok Moon1, IL Han Choo2, Jae Sung Lee2, Hyun Soo Park1, Ji Yeon Son1, In Soon Jung1, Yu Kyeong Kim1, Dong Young Lee2, Jong Inn Woo2, 1Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea; 2Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea.