Ringing cancellation in Carr-Purcell-Meiboom-Gill-type sequences  

作　　者：Shin Utsuzawa Marcus Donaldson Yi-Qiao Song 

机构地区：[1]Schlumberger-Doll Research,Cambridge,MA,02139,USA [2]John A.Paulson School of Engineering and Applied Sciences,Harvard University,Cambridge,MA,02138,USA [3]Athinoula A.Martinos Center for Biomedical Imaging,Department of Radiology,Massachusetts General Hospital,Charlestown,MA,02129,USA

出　　处：《Magnetic Resonance Letters》2022年第4期233-242,共10页磁共振快报（英文）

基　　金：We appreciate many helpful discussions with Martin Hürlimann at Schlumberger-Doll Research.We thank Dr.Isik Kizilyalli,program director of the Advanced Research Projects Agency-Energy(ARPA-E),for the partial support of this research under contract DE-AR0001063.

摘　　要：We propose a four-step phase cycling scheme that can cancel ringings from both the excitation and the refocusing pulses in Carr-Purcell-Meiboom-Gill(CPMG)measurements.It allows accurate measurements of the first echo with short echo spacing tE,yielding improved precision of porosity,permeability,and fluid type identification in porous media study,at a cost of~25%signal reduction.In our example,we achieved tE=100 ms on a 6.8 MHz unilateral NMR sensor without using a Q-switch.These methods can be integrated in all nuclear magnetic resonance(NMR)protocols using CPMG,such as relaxation(T1,T2)and diffusion measurements,and do not require additional hardware(e.g.,Qswitches)to cancel ringing(although it can be used with a Q-switch to further reduce residual ringing).

关 键 词：CPMG Ringing cancellation Phase cycling 

分 类 号：O482.532[理学—固体物理]