Age-dependent normal values of T2* and T2′ in brain parenchyma

Abstract

BACKGROUND AND PURPOSE: Physiologic age-related T2* and T2′ values are required as reference for comparison with disease-related deviations. In our study, T2* and T2′ values (T2 values as control) were determined with MR imaging in healthy subjects to determine standard values and investigate age-related changes. MATERIALS AND METHODS: Data of 50 patients without intraparenchymal pathology and 10 acute stroke patients who underwent MR imaging including a T2 and T2* sequence with 3 echotimes were included. After calculation of T2*, T2′, and T2 maps, the values of gray matter (GM) and white matter (WM) for each hemisphere were measured in 6 distinct regions of interest (ROIs). RESULTS: There was a negative correlation between age and T2* values in the caudate nucleus (r = -0.34 Pearson correlation; P = .001) and lentiform nucleus (r = -0.67; P = .001) and a positive correlation in the occipital (r = 0.41; P = .001) and subcortical (r = 0.45; P = .001) WM. An age dependency for T2′ values was only found for the caudate (r = -0.35; P = .001) and lentiform nucleus (r = -0.69; P = .001). T2′ values in acute stroke were lower than normal in all patients with stroke. CONCLUSION: Decrease in T2′ and T2* values in GM and increase of T2* values in WM correlate with the progress of brain aging. Explanations for decreasing T2′ and T2* values include iron deposition in the caudate and lentiform nucleus. In contrast to T2* values, there is no association of T2′ values with the degree of leukoaraiosis. These age-dependent values can be used as a reference in neurovascular diseases and for the discussion of functional MR imaging data.