一种改良的亚秒级快速自旋回波平面成像（fast-STEAM）序列，该序列结合双极梯度用于体内扩散成像。

A modified sub-second fast-STEAM sequence incorporating bipolar gradients for in vivo diffusion imaging.

作者信息

Yongbi M N, Ding S, Dunn J F

机构信息

Nathan S. Kline Institute, Division of Medical Physics, Orangeburg, NY 10962, USA.

出版信息

Magn Reson Med. 1996 Jun;35(6):911-6. doi: 10.1002/mrm.1910350620.

DOI:10.1002/mrm.1910350620

PMID:8744020

Abstract

A modified high-speed stimulated-echo acquisition mode (STEAM) diffusion sequence (90 degrees-TE/2-90 degrees-TM-[alpha-TE/2-STE]n) incorporating bipolar diffusion gradients that are less sensitive to macroscopic motion-induced artifacts is presented. Diffusion encoding was performed only during the first echo interval (TE1) with bipolar gradients that were implemented on all three mutually orthogonal axes. Calibration measurements on phantoms filled with water, isopropanol, and dimethyl sulfoxide yielded apparent diffusion coefficients (ADC) consistent with published values. Non-ECG-triggered in vivo images acquired on rat brain with relatively high b values (approximately 450 s/mm2) indicated minimal motion artifacts. Evaluated ADCs averaged over the cortex, left mid-brain, right mid-brain, regions yielded (0.91 +/- 0.02), (1.06 +/- 0.02), (1.01 +/- 0.03) x 10(-3) mm2s-1, respectively.

摘要

本文提出了一种改进的高速刺激回波采集模式（STEAM）扩散序列（90度-TE/2-90度-TM-[α-TE/2-STE]n），该序列结合了对宏观运动诱导伪影不太敏感的双极扩散梯度。仅在第一个回波间隔（TE1）期间使用在所有三个相互正交轴上实施的双极梯度进行扩散编码。对填充水、异丙醇和二甲基亚砜的体模进行的校准测量得出的表观扩散系数（ADC）与已发表的值一致。在大鼠大脑上采集的具有相对较高b值（约450 s/mm2）的非心电图触发体内图像显示运动伪影最小。在皮质、左中脑、右中脑区域平均评估的ADC分别为（0.91±0.02）、（1.06±0.02）、（1.01±0.03）×10-3 mm2s-1。