Normal Age-related ADC Value Distribution Of Normal Cranium Bone Marrow: 3.0T MRI-DWI Study

ObjectiveTo evaluate the values of ADC using 3.0T MRI-DWI in the normal cranium bone marrow and to study their relationship with aging.MethodsTwo hundred and twenty normal patients were studied by 3.0T MRI-DWI and divided into 11 groups(younger than 1 year,1～2,3～5,6～10,11～15,16～20,21～30,31～40,41～50,51～60,older than 60).The values of ADC were calculated(b=0, 750s/mm2),and then analyzed the differences among the four bones.The differences of ADC among groups were analyzed by using analysis of variance(ANOVA),and their relationship with age was accessed by using Spearman Correlation.Results(1)Frontal and temporal bone:There were no significant differences of ADCs among different groups in the both bones(P＞0.05).(2)Parietal and occipital bone:The ADCs decreased with aging(r=-0.823 and r=-0.847,P＜0.0001).The ADCs decrease for the groups of 0-1,1-2 and 3-5 was the most obvious;(3)Before 15 years old,the ADCs of frontal and temporal bone were significantly lower than that of parietal and occipital bone(P＜0.001).However after 15 years old,the ADCs of frontal and temporal bone were significantly higher than that of parietal and occipital bone (P＜0.001). Conclusions3.0T MRI-DWI ADC changes with ages in different cranium bones,are of characteristics for cranium bone marrow conversion,which could reflect that the freedom motion of the water molecules decreased rapidly with growing age.