LARGE-ANGLE SPIN-ECHO IMAGING

被引：12

作者：

DIIORIO, G ^{[1
]}

BROWN, JJ ^{[1
]}

BORRELLO, JA ^{[1
]}

PERMAN, WH ^{[1
]}

SHU, HH ^{[1
]}

机构：

[1] WASHINGTON UNIV,SCH MED,EDWARD MALLINCKRODT INST RADIOL,ST LOUIS,MO 63110

来源：

MAGNETIC RESONANCE IMAGING | 1995年 / 13卷 / 01期

关键词：

LIVER; MR; MAGNETIC RESONANCE (MR); PULSE SEQUENCES; RAPID IMAGING;

D O I：

10.1016/0730-725X(94)00082-E

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 study was undertaken to assess the use of excitation flip angles greater than 90 degrees for T-1 weighted spin-echo (SE) imaging with a single 180 degrees refocusing pulse and short TR values, Theoretical predictions of signal intensity for SE images with excitation pulse angles of 90-180 degrees were calculated based on the Bloch equations and then measured experimentally from MR images of MnCl2 phantoms of various concentrations, Liver signal-to-noise ratios (SNR) and liver-spleen contrast-to-noise ratios (CNR) were measured from breathhold MR images of the upper abdomen in 16 patients using 90 and 110 degrees excitation flip angles. The theoretical predictions showed significant improvements in SNR with excitation flip angles >90 degrees, which were more pronounced at small TR values. The phantom studies showed reasonably good agreement with the theoretical predictions in correlating the excitation pulse angle with signal intensity, In the human imaging studies, the 110 degrees excitation pulse angle resulted in a 7.4% (p < .01) increase in liver SNR and an 8.2% (p = .2) increase in liver-spleen CNR compared to the 90 degrees pulse angle at TR = 275 ms. Increased signal intensity resulting from the use of large flip angle excitation pulses with a single echo SE pulse sequence was predicted and confirmed experimentally in phantoms and humans,

引用

页码：39 / 44

页数：6

共 17 条

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