The Correlation of Hippocampal T2-Mapping with Neuropsychology Test in Patients with Alzheimer's Disease

Objectives: 1) To deduce T-2, the inverse of the transverse relaxation rate (R-2), in the hippocampus of healthy adults; 2) to investigate the brain iron deposition in Alzheimer's disease (AD) patients and age-matched healthy controls using T-2-values. Methods: T-2-weighted data from the bilateral-hippocampi of ten AD patients and sixty healthy controls were collected at six echo time points using multi-slice multi-echo turbo spin echo (MSME-TSE) imaging on a 3.0 T MR-scanner, followed by the neuropsychological testing. The correlations between T-2-values and Mini-Mental State Examination (MMSE) scores were investigated on group-wise basis (covariates in the group-wise analyses: gender, age, side and healthy/AD). Results: There were no significant differences in hippocampal T-2-values on intra-gender and inter-gender basis (P > 0.05). Hippocampal T-2-values of both sides were similar (right: 85.2 +/- 2.4 milliseconds; left: 85.3 +/- 2.5 milliseconds). The bilateral hippocampal T-2 values correlated moderately with age (right: r = -0.59; left: -0.58; P < 0.001). The AD-group had significantly lower T-2-values in the hippocampus when compared to normal controls (P < 0.001) and such low T-2-values had a strong positive correlation with the MMSE score (R2 = 0.97; P < 0.05). Conclusion: Patients with AD showed significantly lower T-2 values, which can be attributed to the increased iron depositions in the hippocampus. A positive correlation between T-2-values and cognition scores suggests that quantitative T-2 can be used in the early diagnosis of AD and in the monitoring of the treatment response.