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) underwent T 1ρ MRI on a Siemens 1.5T Scanner. T 1ρ values were automatically calculated from the left and right hippocampus region using in‐house developed software. Bonferroni 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 patients might be associated with the increased plaques burden. 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. J. Magn. Reson. Imaging 2009;29:1008–1012. © 2009 Wiley‐Liss, Inc.