CAUSE OF SIGNAL LOSS IN MR IMAGES OF OLD HEMORRHAGIC LESIONS
CAUSE OF SIGNAL LOSS IN MR IMAGES OF OLD HEMORRHAGIC LESIONS
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DOI：
10.1148/radiology.174.2.2296664
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发表时间：
1990-02-01
期刊：
影响因子：
19.7
通讯作者：
HENKELMAN, RM
中科院分区：
文献类型：
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作者：
HARDY, PA;KUCHARCZYK, W;HENKELMAN, RM
脑部陈旧性出血性病变周围有一条含含铁血黄素的组织带。这一区域在长回声时间(TE)射频(RF)自旋回波磁共振(MR)图像和梯度回波MR图像上通常具有低信号强度。为了确定该波段信号丢失的原因，作者使用180度的射频自旋回波技术测量了对这样一个区域进行成像所产生的信号。脉冲从TE/2逐渐移位。信号的增量损失很小。使用含有铁颗粒的琼脂模型，作者还表明，信号损失主要是由于磁梯度中的扩散造成的。他们的结论是，晚期出血周围暗带的大部分信号损失是由于磁性不均匀区域的扩散造成的。
Old hemorrhagic lesions in the brain are characteristically surrounded by a band of hemosiderin-containing tissue. This region is typically of low signal intensity on long-echo-time (TE) radio-frequency (RF) spin-echo magnetic resonance (MR) images and on gradient-echo MR images. To determine the cause of signal loss in this band, the authors measured the signal that arises from imaging such a region with use of an RF spin-echo technique with a 180.degree. pulse incrementally displaced from TE/2. The incremental loss of signal was small. Using an agar phantom containing iron particles, the authors also showed that signal loss results primarily from diffusion in magnetic gradients. They conclude that most signal loss in the dark band surrounding areas of late-stage hemorrhage arises from diffusion in areas of magnetic inhomogeneity.