Authors:
Hayriye Aktaş Dinçer
and
Didem Gökçay
Affiliation:
Middle East Technical University, Turkey
Keyword(s):
Brain Aging, Spin Lattice Relaxation Time (T1), T1 Mapping, Signal-to-Noise Ratio (SNR), Contrast to Noise Ratio (CNR), Gray-White Ratio (GWR), Segmentation.
Abstract:
During healthy aging, the brain undergoes several structural changes such as atrophy and volumetric changes.
Although less evident, changes in tissue concentration also occur. Such differences in brain tissues introduce
prominent low contrast effects to the MRI images of the aging population, causing segmentation problems in
the data processing pipeline. Measures of tissue characteristics such as T1 provide unique and complementary
information to widely used measures of brain signal characteristics. In this study, multiple Fast Low Angle
Shot (FLASH) images are collected for T1 mapping of whole brains from young and old adults. Tissue signal
characteristics are evaluated on predefined regions and compared across Magnetization Prepared Rapid
Gradient Echo (MPRAGE) and T1 maps. Additionally, segmentation performance is analyzed. As a result,
we found that T1 maps are superior to MPRAGE protocol in terms of contrast, especially within sub-cortical
areas. Furthermore, degradatio
n of grey-white-ratio (GWR) due to aging processes is observed to be less
pronounced in T1 estimated whole brain images. Moreover, sensitivity of T1 maps (54.6%) are higher than
MPRAGE images (34.4%) in detection of sub-cortical gray matter. In sum we concur that T1 maps provide
better avenues to investigate age related morphological changes in the brain.
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