Early Marker for Alzheimer's Disease: Hippocampus T1rho (T _1ρ) Estimation

Purpose: To evaluate the T1rho (T _1ρ) MRI relaxation time in hippocampus in the brain of Alzheimer's disease (AD), mild cognitive impairment (MCI), and control, and to determine whether the T _1ρ shows any significant difference between these cohorts. Materials and Methods: With informed consent, AD (n 49), MCI (n = 48), and age-matched control (n = 31) un- derwent T _1ρ MRI on a Siemens 1.5T Scanner. T _1ρ values were automatically calculated from the left and right hip- pocampus region using in-house developed software. Bon- ferroni post-hoc multiple comparisons was performed to compare the T _1ρ value among the different cohorts. Results: Significantly higher T _1ρ values were observed both in AD (P = 0.000) and MCI (P = 0.037) cohorts compared to control; also, the T _1ρ in AD was significantly high over (P = 0.032) MCI. Hippocampus T _1ρ was 13% greater in the AD patients than control, while in MCI it was 7% greater than control. Hippocampus T _1ρ in AD patients was 6% greater than MCI. Conclusion: Higher hippocampus T _1ρ values in the AD pa- tients might be associated with the increased plaques bur- den. A follow-up study would help to determine the efficacy of T _1ρ values as a predictor of developing AD in the control and MCI individuals.