MULTIPLE SPIN-ECHO MR IMAGING OF THE BODY - IMAGE-CONTRAST AND MOTION-INDUCED ARTIFACT
MULTIPLE SPIN-ECHO MR IMAGING OF THE BODY - IMAGE-CONTRAST AND MOTION-INDUCED ARTIFACT
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DOI：
10.1016/0730-725x(88)90128-2
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发表时间：
1988-09-01
影响因子：
2.5
通讯作者：
RIFKIN, MD
中科院分区：
文献类型：
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作者：
MITCHELL, DG;VINITSKI, S;RIFKIN, MD
对于给定的TR和TE，图像质量随获得的自旋回波数的变化而变化。为了研究这在临床成像中的重要性，共有4名患者和9名志愿者对腹部（n=7）和/或骨盆（n=8）进行了MRI检查，其中包括至少2个序列，具有相同的TR(2000或2500 ms), TE （80 ms）和其他参数，但具有不同的再聚焦脉冲序列。序列包括单回波(S)，非对称和对称双回波（AD和SD）和四回波(Q)技术。通过3名独立MRI放射科医师的盲检，计算运动“鬼影”的信差、信差噪比和强度，测量图像对比度和运动伪影的严重程度。信号差异减小的顺序为S、SD、AD、Q， 3种肝脏病变，S技术均比SD技术更清晰。这些观测结果与多个180度累积误差造成的信号损失一致。射频脉冲。鬼影伪影的增强顺序为Q、SD、AD、S，与均匀回波重相位的有益运动伪影减弱效果一致。了解多回波成像的这些影响，可以使人们对成像方案做出明智的决定，而不是简单地获得“因为它们是免费的”的多回波。
For a given TR and TE, image quality changes when the number of spin echoes obtained is varied. To investigate the importance of this in clinical imaging, a total of 4 patients and 9 volunteers had MRI examinations of the abdomen (n=7) and/or pelvis (n=8) which included at least 2 sequences with identical TR (2000 or 2500 ms), TE (80 ms) and other parameters, but with a different series of refocusing pulses. Sequences included single-echo (S), asymmetric and symmetric double-echo (AD and SD) and quadruple-echo (Q) techniques. Image contrast and severity of motion-induced artifact was measured via blind examination by 3 independent MRI radiologists and calculation of signal-difference, signal-difference-to-noise ratios and intensity of motion-induced "ghost artifact". The order of decreasing signal differences was S, SD, AD and Q, and all of three liver lesions were better seen with S than with SD techniques. These observations are consistent with signal loss from cumulative inaccuracies from multiple 180.degree. RF pulses. The order of increasing intensity of ghost artifact was Q, SD, AD and S, consistent with the beneficial motion artifact-reducing effects of even-echo rephasing. Knowledge of these effects of multi-echo imaging allows one to make informed decisions about imaging protocols rather than to simply obtain multiple echoes "because they are free.".