Research Of MR T2* Parameter Imaging Based On DANTE Black Blood Prepared Sequence

Mediterranean anemia,hereditary hemochromatosis,sickle cell disease are closely related to human iron content.In magnetic resonance imaging(MRI),the iron content of the human body cause the magnetic field inhomogeneity,which leads to the transverse magnetization vector decay faster(T2*decay).Therefore,the quantitative analysis of T2*value can reflect the iron content of human tissue effectively.At present,several methods can be used to measure the T2*value of human tissue quantitatively.However,the accuracy of T2*parameters should be improved better,and deeper research is still needed to suppress the blood flow signal and reduce the scan time.The main purpose of this study is to improve the T2*image accuracy by reducing blood flow signal interference and improving image quality.In the present study,phantom experiments and human experiments are designed to analysis blood effect and image quality of Gradient Recalled Echo(GRE)sequence,Motion-Sensitized Driven Equilibrium(MSDE)sequence and Delay Alternating with Nutation for Tailored Excitation(DANTE)sequence.Second,the joint image reconstruction algorithm is proposed based on the Joint Image Reconstruction and Sensitivity Estimation in SENSE(JSENSE)algorithm.Image quality reconstructed by SENSE,JSENSE and joint image reconstruction algorithm should be analyzed.The final task is to scan phantom by DANTE sequence and reconstruct images of ten echoes by JSENSE and joint reconstruction algorithm separately,then map the T2*images and analysis T2*image quality.Main research results are given as follows:(1)DANTE black blood sequence inhibit blood flow signal without affecting the T2*values.(2)the image joint reconstruction algorithm can reconstruct two sets of different contrast images simultaneously,and improve the image quality effectively,T2*fitting image is more accurate.The results shows that the DANTE sequence can reduce the blood flow signal interference in T2*imaging,the joint image reconstruction algorithm can reduce the scanning time,improve the image quality,and make the T2*image more accurate.