Abstract
PURPOSE
Hippocampal volumetry is the most widely used structural MRI biomarker of Alzheimer’s disease (AD), and state-of-the-art, automatic hippocampal segmentation can be obtained using longitudinal FreeSurfer. In this study, we compare the diagnostic AD performance of a single time point, multi-atlas method using the Harmonized Hippocampal Protocol (HHP) to FreeSurfer (FS).
METHOD AND MATERIALS
Baseline and month 12 MRI scans from the “complete annual year 2 visits” 1.5-T standardized ADNI dataset were used [169 normal controls (NC), 234 mild cognitive impaired (MCI), 101 AD]. A multi-atlas, affine registration, patch-based segmentation method (MRP) using 40 HHP segmentations in the atlas (12 NC, 11 MCI, 17 AD) was applied to segment the hippocampi. Static- and longitudinal FS (v5.1.0, default parameters) were also applied to segment the hippocampi. Atrophy rate calculated as percent volume change from baseline to month 12 was estimated for the three methods, and diagnostic performance was evaluated using the area under the receiver operating characteristic curve (AUC) of pairwise diagnostic group comparisons.
RESULTS
Mean (SD) atrophy rates were as follows (MRP / static FS / longitudinal FS): NC -0.86 (2.46) / -1.39 (5.41) / -1.63 (2.54), MCI -2.38 (3.28) / -3.69 (5.48) / -3.25 (3.53), AD -4.23 (3.07) / -4.29 (5.32) / -4.83 (3.74). Diagnostic performances were as follows (AUC; MRP / static FS / longitudinal FS): NC vs. MCI 0.65 / 0.67 / 0.64, NC vs. AD 0.80 / 0.69 / 0.76, MCI vs. AD 0.66 / 0.53 / 0.62. The MRP AUC was significantly larger (DeLong) than the static FS AUC for NC vs. AD and MCI vs. AD. In the remaining pairwise group comparisons, MRP AUCs did not differ significantly from FS AUCs.
CONCLUSION
The MRP method discriminated AD from either NC or MCI significantly better than static FS, and it was as good as longitudinal FS, which exploits information from both time points simultaneously. Moreover, the standard deviation of the atrophy rate was comparable to that of longitudinal FS, emphasizing longitudinal robustness of segmentations of the proposed method. The combination of MRP and HHP is a robust and fast alternative to FreeSurfer, especially in a setting with many time points.
Hippocampal volumetry is the most widely used structural MRI biomarker of Alzheimer’s disease (AD), and state-of-the-art, automatic hippocampal segmentation can be obtained using longitudinal FreeSurfer. In this study, we compare the diagnostic AD performance of a single time point, multi-atlas method using the Harmonized Hippocampal Protocol (HHP) to FreeSurfer (FS).
METHOD AND MATERIALS
Baseline and month 12 MRI scans from the “complete annual year 2 visits” 1.5-T standardized ADNI dataset were used [169 normal controls (NC), 234 mild cognitive impaired (MCI), 101 AD]. A multi-atlas, affine registration, patch-based segmentation method (MRP) using 40 HHP segmentations in the atlas (12 NC, 11 MCI, 17 AD) was applied to segment the hippocampi. Static- and longitudinal FS (v5.1.0, default parameters) were also applied to segment the hippocampi. Atrophy rate calculated as percent volume change from baseline to month 12 was estimated for the three methods, and diagnostic performance was evaluated using the area under the receiver operating characteristic curve (AUC) of pairwise diagnostic group comparisons.
RESULTS
Mean (SD) atrophy rates were as follows (MRP / static FS / longitudinal FS): NC -0.86 (2.46) / -1.39 (5.41) / -1.63 (2.54), MCI -2.38 (3.28) / -3.69 (5.48) / -3.25 (3.53), AD -4.23 (3.07) / -4.29 (5.32) / -4.83 (3.74). Diagnostic performances were as follows (AUC; MRP / static FS / longitudinal FS): NC vs. MCI 0.65 / 0.67 / 0.64, NC vs. AD 0.80 / 0.69 / 0.76, MCI vs. AD 0.66 / 0.53 / 0.62. The MRP AUC was significantly larger (DeLong) than the static FS AUC for NC vs. AD and MCI vs. AD. In the remaining pairwise group comparisons, MRP AUCs did not differ significantly from FS AUCs.
CONCLUSION
The MRP method discriminated AD from either NC or MCI significantly better than static FS, and it was as good as longitudinal FS, which exploits information from both time points simultaneously. Moreover, the standard deviation of the atrophy rate was comparable to that of longitudinal FS, emphasizing longitudinal robustness of segmentations of the proposed method. The combination of MRP and HHP is a robust and fast alternative to FreeSurfer, especially in a setting with many time points.
Original language | English |
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Publication date | 2014 |
Publication status | Published - 2014 |
Event | 100th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA 2014) - Chicago, United States Duration: 30 Nov 2014 → 5 Dec 2014 Conference number: 100 http://rsna2014.rsna.org/ |
Conference
Conference | 100th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA 2014) |
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Number | 100 |
Country/Territory | United States |
City | Chicago |
Period | 30/11/2014 → 05/12/2014 |
Internet address |