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IC‐P‐146: Amyloid burden measured by T1‐rho–weighted MRI in Down syndrome
Author(s) -
Koran Mary Ellen,
Hohman Timothy,
Meda Shashwath,
Cobb Jared,
Gore John,
Welch Brian,
ThorntonWells Tricia
Publication year - 2013
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2013.05.143
Subject(s) - parahippocampal gyrus , magnetic resonance imaging , medicine , biomarker , down syndrome , positron emission tomography , gyrus , nuclear medicine , neuroimaging , pathology , temporal lobe , radiology , biology , psychiatry , genetics , epilepsy
Background: Individuals with Down syndrome (DS; trisomy 21) are at increased risk for Alzheimer’s disease (AD) and they develop amyloid beta plaques (Ab) by 30 years because they have 3 copies of the gene encoding amyloid precursor protein (APP). Therefore, they are an ideal population in which to validate Ab biomarkers. Currently, brain levels of Ab are measured invasively via lumbar puncture or radioactive ligand-based positron emission tomography. Non-invasive biomarkers are necessary for early screening and repeatability. Non-invasive T1-rho-weighted magnetic resonance imaging (T1r MRI) detects Ab in transgenic mouse models of AD and shows decreases at plaque deposition; we are investigating its use as an early biomarker of Ab in DS subjects. Methods: The current sample includes 9 DS subjects (ages 36-54) compared to 9 subjects (ages 54-89) with normal cognition (NC). T1r dispersion curves were quantified in AD-related regions of interest (ROIs) delineated using FreeSurfer. The dispersion curves include quantified T1, T2, and two T1r values (at FSL1⁄4275 and 550 Hz). Curve features between DS and NC were compared and APOE status and family history of AD will be incorporated into analyses. Results: DS subjects showed a lower slope between the two T1rho data points compared to NC subjects in a priori ROIs, including the left amygdala (p1⁄4.005), left temporal pole (p1⁄4.013), right isthmus of the cingulate gyrus (p1⁄4.029), and right parahippocampal gyrus (p1⁄4.012). The contralateral temporal pole and isthmus of the cingulate trended in the same direction but did not reach significance. Preliminary analysis suggests APOE status and family history modulate the relationship between diagnostic category and T1r. Conclusions: Quantitative T1r and its dispersion curve followed the expected between-group trend for detecting Ab (DS < NC). Recruitment is ongoing to obtain 20 subjects per group. If further validated in larger samples and in ex vivo studies, T1r could be used as a non-invasive alternative to PET imaging of Ab for early identification of patients at highest risk for AD, allowing for earlier disease treatment and monitoring of progression.