Measurement of phase value of the deep gray nuclei in underage brain

Objective To measure the phase values of the deep gray nuclei by using susceptibility weighted imaging(SWI) in underage brains,and to investigate the correlation between the phase value and age.Methods A total of 105 healthy juveniles were examined in this study by using MRI conventional sequence and SWI.Their ages ranged from 0 to 18 years(0-＜ 1 year,60 cases; 1-＜3 years,10 cases; 3-7 years,10 cases; 7-12 years,10 cases; 12-18 years,15 cases).Phase values of deep gray nuclei were measured.The correlation between phase value and age was analyzed by Spearman correlation method.Results During 0-3 years,the phase value of caudate nucleus was the lowest within the same age group (0-＜ 1 year:left-0.0433 ± 0.0291,right-0.0369 ± 0.0215 ; 1-＜ 3 years:left-0.0369 ± 0.0215,right-0.0384 ± 0.0259),whereas the phase value of red nucleus was the highest (0-＜ 1 year:left 0.0286-0.0380,right 0.0254 ±0.0361 ; 1-＜3 years:left 0.0325 ±0.0237,right 0.0395 ±0.0270).After 3 years old,the phase value of globus pallidus was the lowest within the same age group (3-＜7 years:left-0.0967 ± 0.0656,right-0.0953 ± 0.0617; 7-＜ 12 years:left-0.1870 ± 0.0531,right-0.1724 ±0.0547; 12-＜ 18 years:left-0.2037 ±0.0492,right-0.1849-±0.0324),whereas the phase value of thalamus was the highest (3-＜ 7 years:left-0.0019 ± 0.0225,right -0.0007 ± 0.0167 ; 7-＜ 12 years:left-0.0067 ± 0.0104,right-0.0064 ± 0.0118 ; 12-＜ 18 years:left-0.0204 ± 0.0181,right-0.0172 ± 0.0133).During 0-18 years,a moderate negative correlation between phase values of bilateral caudate nucleus,globus pallidus,red nucleus,substantia nigra and age were observed (rs =-0.483,-0.497,-0.67,-0.621,-0.489,-0.43,-0.552,-0.58 respectively) A low negative correlation between phase values of bilateral putamen,thalamus and age were observed (rs =-0.272,-0.213,-0.382,-0.366 respectively).Conclusions There is a negative correlation between phase value and age in the deep gray nuclei of underage brains.And the phase value may be a useful index in the diagnosis of iron deposition related diseases. Key words: Magnetic resonance imaging;  Brain;  Age factors