Ultimate intrinsic signal-to-noise ratio in MRI

被引:175
作者
Ocali, O [1 ]
Atalar, E [1 ]
机构
[1] Johns Hopkins Univ, Sch Med, Dept Radiol, Baltimore, MD 21287 USA
关键词
SNR optimization; RF coil design; skin effect; focusing;
D O I
10.1002/mrm.1910390317
中图分类号
R8 [特种医学]; R445 [影像诊断学];
学科分类号
1002 ; 100207 ; 1009 ;
摘要
A method to calculate the ultimate intrinsic signal-to-noise ratio (SNR) in a magnetic resonance experiment for a point inside an arbitrarily shaped object is presented. The ultimate intrinsic SNR is determined by body noise. A solution is obtained by optimizing the electromagnetic field to minimize total power deposition while maintaining a constant righthand circularly polarized component of the magnetic field at the point of interest. A numerical approximation for the optimal field is found by assuming a superposition of a large number of plane waves. This simulation allowed estimation of the ultimate intrinsic SNR attainable in a human torso model. The performance of six coil configurations was evaluated by comparing the SNR of images obtained by the coils with the ultimate values. In addition, the behavior of ultimate intrinsic SNR was investigated as a function of main field strength. II: was found that the ultimate intrinsic SNR increases better than linearly with the main magnetic field up to 10 T for our model. It was observed that for field strengths of 4 T or higher, focusing is required to reach the ultimate intrinsic SNR.
引用
收藏
页码:462 / 473
页数:12
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