Alzheimer's Imaging Consortium.

Area of Science:

• Neuroimaging
• Biomedical Engineering

Background:

• Alzheimer's disease (AD) diagnosis relies on costly PET and MRI scans.
• Current MRI methods for detecting beta-amyloid (Aβ) plaques require high fields and long scan times, unsuitable for clinical use.
• A novel MRI technique, multiple-echo frequency-domain image contrast (MEFIC), was explored to improve signal-noise ratio and T2* contrast for high-resolution imaging.

Purpose of the Study:

• To investigate the feasibility of using MEFIC MRI at 3T to image Aβ plaques in living human brains.
• To assess the potential of MEFIC MRI as a more accessible diagnostic tool for AD.

Main Methods:

• Eighteen mild cognitive impairment (MCI) and twelve normal (CN) subjects participated.
• MEFIC MRI scans were acquired at 3T with a resolution of 0.4 x 0.4 x 0.7 mm³ and a scan time of 12:49.
• Aβ-PET scans using Florbetapir were performed, and images were co-registered using SPM12.

Main Results:

• MEFIC MRI maps showed clear correspondence with Aβ-PET (SUVr) maps.
• Aβ plaque load in gray matter diminished the contrast between gray and white matter in MEFIC images.
• MEFIC imaging provided a 10x greater T2* contrast-to-noise ratio than conventional T2* imaging.
• A significant negative correlation was found between Aβ-PET SUVr values and MEFIC signal in cortical gray matter.

Conclusions:

• Aβ plaques can be detected in the human brain at 3T using MEFIC T2* MRI.
• MEFIC MRI T2* signal in gray matter negatively correlates with Aβ-PET SUVr, validating its potential for AD diagnosis.