Harpen M D
University of South Alabama, Department of Radiology, Mobile 36617.
Med Phys. 1990 Jul-Aug;17(4):686-90. doi: 10.1118/1.596467.
Presented is a derivation of an exact closed-form expression for the spectra of resonant frequencies for magnetic resonance imaging birdcage coils in the limit of long coils with many elements. Results of the analysis are compared with observation in a variety of birdcage coils where it is shown that for even relatively short coils the progression of resonant frequencies are of the form omega m = omega 1m +/- 1/2 + low pass; -high pass, with m integer and omega 1 the primary resonance.
给出了在具有许多元件的长线圈极限情况下，磁共振成像鸟笼线圈共振频率谱的精确闭式表达式的推导。将分析结果与各种鸟笼线圈中的观测结果进行了比较，结果表明，即使对于相对较短的线圈，共振频率的进展形式为ωm = ω1m ± 1/2 + 低通；-高通，其中m为整数，ω1为初级共振。
