R2 ~ * Application In Normal Brain Tissue Iron Content Detection

Part Ⅰ:The application of ESWAN in evaluating the iron concentration in vitro experimentObjective Discussion the application value of Enhanced T2Star Weighted Angiography (ESWAN) sequence in measuring iron concentration in vitro model.Methods use4mg/ml ultrasmall superparamagnetic iron oxide (USPIO),Times diluted as0.4mg/ml,0.02mg/ml,0.01mg/ml,0.005mg/ml,0.0025mg/ml,0.00125mg/ml,0.000625mg/ml, Omg/ml mixed with distilled water and agarose; put in24hole boards. Each level is provided for10holes. The MR is GE HDX3.0T,ESWAN protocal parameters as Echo number=8, Flip Angle=20°, bandwidth=31.25, FOV240mm×240mm, thickness=2.0mm, Freq416, phase356, phase Fov1.0mm, frep A/P.TR is68.0ms, the TE time of every echo is7.0ms,15.0ms,23.0ms,31.0ms,39.0ms,47.0ms,54.9ms,62.9ms.Result The kind of0.04mg/ml concentration, due to iron concentration is too high, the quality of image is too poor to be evaluated, the other holes, R2*increasing with iron concentration increasing, linear correlation is obviously, coefficient of correlation is0.989, and P<0.001.Conclusion ESWAN sequence which can reflect the iron concentration of the model in vitro. Part II:The value of R2*in the estimate of normal brain iron depositionObjective To determine the values of R.2in estimating the iron accumulation in the brain gray matter nucleus of healthy volunteers from different ages, and provide standard R2*of healthy brain in different ages to early diagnose many degenerative diseases.Methods Select73healthy volunteers ages from7month to79-years-old, the average of ages is36.95±19.86. The MR scanner is GE HDX3.0T, head ax T1WI, T2WI, DWI was performed to observe the general situation of brain, the R2value was measured by ESWAN. the median3slices of Caudate nucleus, globus pallidus(GP), putamen, thalamus,and the middle2slices of red nucleus and substantia nigra(SN) were selected to measure the R2*value, the final results is the average value of the media slices. SAS9.2is used to data analysis.Results The R2value of globus pallidus is the highest, and then red nucleus,substantia nigra, putamen, Caudate nucleus, thalamus are the second to the sixth. The increasing rates of R2*value were different, GP is the quickest, the Caudate nucleus is the slowest. The R2value of GP, SN and thalamus reach a plateau in early adulthood, but the age-related R2*curve in Caudate nucleus, putamen, red nucleus increasing slowly, and reach the95%of the max value in39.09、58.30、53.85separately, the R2*values of every grey nucleus versus age shows an exponential increase with increasing age. Good correlation coefficients were found for thalamus(R2=0.58), Caudate nucleus (R2=0.80),GP (R2=0.78), putamen (R2=0.76), and SN (R2=0.70), red nucleus (R2=0.80)when compared with findings in the postmortem study.Conclusion R2measurements can be used to quantify brain iron accumulation and can be used to better evaluate neurodegenerative diseases associated with iron deposition.