Journal of Magnetic Resonance Imaging · Feb 2, 2017
Relationship between aging and T₁ relaxation time in deep gray matter: A voxel-based analysis
By Okubo G, Okada T, Yamamoto A et al.
PURPOSE: To investigate age-related changes in T₁ relaxation time in deep gray matter structures in healthy volunteers using magnetization-prepared 2 rapid acquisition gradient echoes (MP2RAGE). MATERIALS AND METHODS: In all, 70 healthy volunteers (aged 20-76, mean age 42.6 years) were scanned at 3T magnetic resonance imaging (MRI). A MP2RAGE sequence was employed to quantify T₁ relaxation times. After the spatial normalization of T₁ maps with the diffeomorphic anatomical registration using the exponentiated Lie algebra algorithm, voxel-based regression analysis was conducted. In addition, linear and quadratic regression analyses of regions of interest (ROIs) were also performed. RESULTS: With aging, voxel-based analysis (VBA) revealed significant T₁ value decreases in the ventral-inferior putamen, nucleus accumbens, and amygdala, whereas T₁ values significantly increased in the thalamus and white matter as well (P < 0.05 at cluster level, false discovery rate). ROI analysis revealed that T₁ values in the nucleus accumbens linearly decreased with aging (P = 0.0016), supporting the VBA result. T₁ values in the thalamus (P < 0.0001), substantia nigra (P = 0.0003), and globus pallidus (P < 0.0001) had a best fit to quadratic curves, with the minimum T₁ values observed between 30 and 50 years of age. CONCLUSION: Age-related changes in T₁ relaxation time vary by location in deep gray matter. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. MAGN. RESON. IMAGING 2017;46:724-731.