3-DIMENSIONAL ECHO-PLANAR MR SPECTROSCOPIC IMAGING AT SHORT ECHO TIMES IN THE HUMAN BRAIN
3-DIMENSIONAL ECHO-PLANAR MR SPECTROSCOPIC IMAGING AT SHORT ECHO TIMES IN THE HUMAN BRAIN
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DOI：
10.1148/radiology.192.3.8058941
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发表时间：
1994-09-01
期刊：
影响因子：
19.7
通讯作者：
LEBIHAN, D
中科院分区：
文献类型：
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作者：
POSSE, S;DECARLI, C;LEBIHAN, D
目的：证明在人脑中使用传统临床成像仪在短回波时间（13 毫秒）下进行三维回波平面光谱成像 (EPSI) 的可行性。 材料和方法：在数据采集过程中使用读出梯度的周期性反转，以在一次激励中同时编码化学位移和一个空间维度。通过基于过采样的改进采集和处理方法避免了混叠伪影。采用适应卵圆形脑形状的双重外体积抑制技术，可强烈减少颅外脂质共振。 结果：在 34 分钟内对八个切片（每个切片具有 32 x 32 体素（0.75 cm(3)））进行体内三维空间编码，并获得四个信号平均值。肌醇、胆碱、肌酸、谷氨酸和谷氨酰胺以及N-乙酰天冬氨酸共振的光谱分辨率和信噪比（S/N）与之前用传统相位编码记录的光谱分辨率和信噪比（S/N）一致。结论：EPSI大大减少了三维空间编码的采集时间，并产生与传统技术相似的光谱质量，而不影响单位时间和单位体积的S/N。
PURPOSE: To demonstrate the feasibility of three-dimensional echo-planar spectroscopic imaging (EPSI) at short echo time (13 msec) with a conventional clinical imager in the human brain.MATERIALS AND METHODS: Periodic inversions of a readout gradient were used during data acquisition to simultaneously encode chemical shift and one spatial dimension in one excitation. Aliasing artifacts were avoided with a modified acquisition-and-processing method based on oversampling. A double outer-volume suppression technique that adapts to the ovoid brain shape was used to strongly reduce extracranial lipid resonances.RESULTS: Three-dimensional spatial encoding in vivo of eight sections with 32 x 32 voxels each (0.75 cm(3)) was performed in 34 minutes with four signal averages. The spectral resolution and signal-to-noise ratio (S/N) of resonances of inositol, choline, creatine, glutamate and glutamine, and N-acetyl aspartate were consistent with those previously recorded with conventional phase encoding.CONCLUSION: EPSI substantially reduces acquisition time for three-dimensional spatial encoding and yields a spectral quality similar to that obtained with conventional techniques without affecting the S/N per unit time and unit volume.