MR elastography study of the brain in healthy volunteers / 中华放射学杂志

ABSTRACT

Objective To evaluate the shear stiffness of brain by MR elastography (MRE) in healthy Chinese volunteers and to assess the association between the cerebral shear stiffness and age. Methods Brain MRE studies were performed on 105 healthy volunteers. The shear stiffness of brain parencham was measured by local frequency estimation (LFE) algorithm. The differences of the shear stiffness between white matter(WM) and grey matter(GM) were analyzed by independent sample t test; the differences of brain parenchyma shear stiffness between male and female were estimated by independent sample t test. Spearman test was used to analyze the correlation between age and the shear stiffness of parenchyma; the volunteers were divided into two groups (age ≤ 40 and age > 40) and the correlation between age and shear stiffness of parencbyma in each group were analyzed separately. Results The shear stiffness of whiter matter [(23.1±5.7) kPa] was higher than that of grey matter[(11.3±2.6) kPa], and the difference was significant (t = 19.34, P < 0.01). In male, the shear stiffness of WM and GM was (23.4±5.8) kPa and (11.4±2.8) kPa respectively; while in female, it was (22.8±5.6) kPa and (11.1±2.5) kPa respectively. No sex differences were found in the stiffness of white matter or gray matter (t = - 0.534, - 0.606, P > 0.05). An age-dependent trend was observed in the stiffness of grey matter(r =0.315, P < 0.01),while not in whiter matter (r = 0.183, P > 0.05). When the shear stiffness of subjects no more than 40 years old was analysed, the age-dependent trend of shear stiffness was found both in white matter and gray matter(r = 0.251,0.235, P < 0.05); While in subjects over 40 years old, the age-dependent rend of shear stiffness was not found in white matter or gray matter(r = 0.181, - 0.001, P > 0.05). Conclusions The shear stiffness of WM is significantly higher than that of GM. No obvious sex difference was found in the stiffness of brain parenchyma. The shear stiffness of GM increases with age; the age-related increase of shear stiffness of WM was only found in subjects under 40 years old.