Gai Neville D, Butman John A
Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA.
J Magn Reson Imaging. 2015 May;41(5):1440-6. doi: 10.1002/jmri.24679. Epub 2014 Jun 30.
The purpose of this study is to design and evaluate a new reduced scan time three-dimensional (3D) FLuid Attenuated Inversion Recovery (FLAIR) sequence.
The 3D FLAIR sequence was modified so that the repetition time was modulated in a predetermined smooth manner (3D mFLAIR). Inversion times were adjusted accordingly to maintain cerebrospinal fluid (CSF) suppression. Simulations were performed to determine SNR for gray matter (GM), white matter (WM), and CSF. Fourteen volunteers were imaged using the modified and product sequence. SNR measurements were performed in GM, WM, and CSF. Mean value and the 95% confidence interval ([CI]) were assessed. Scan time for the 3D FLAIR and 3D mFLAIR sequences was measured.
There was no statistically significant difference in the SNR measured in GM (P value = 0.5; mean SNR = 42.8 [CI]: 38.2-45.5 versus 42.2 [CI]: 38.3-46.1 for 3D FLAIR and 3D mFLAIR, respectively) and WM (P value = 0.25; mean SNR = 32.1 [CI]: 30.3-33.8 versus 32.9 [CI]: 31.1-34.7). Scan time reduction greater than 30% was achieved for the given parameter set with the 3D mFLAIR sequence.
Scan time for 3D FLAIR can be effectively reduced by modulating repetition and inversion time in a predetermined manner while maintaining the SNR and CNR of a constant TR sequence.
本研究的目的是设计并评估一种新的扫描时间缩短的三维（3D）液体衰减反转恢复（FLAIR）序列。
对3D FLAIR序列进行修改，使重复时间以预定的平滑方式进行调制（3D mFLAIR）。相应地调整反转时间以维持脑脊液（CSF）抑制。进行模拟以确定灰质（GM）、白质（WM）和CSF的信噪比。使用修改后的序列和产品序列对14名志愿者进行成像。在GM、WM和CSF中进行信噪比测量。评估平均值和95%置信区间（[CI]）。测量3D FLAIR和3D mFLAIR序列的扫描时间。
GM中测量的信噪比无统计学显著差异（P值 = 0.5；3D FLAIR和3D mFLAIR的平均信噪比分别为42.8 [CI]：38.2 - 45.5和42.2 [CI]：38.3 - 46.1），WM中也无统计学显著差异（P值 = 0.25；平均信噪比分别为32.1 [CI]：30.3 - 33.8和32.9 [CI]：31.1 - 34.7）。对于给定参数集，3D mFLAIR序列实现了大于30%的扫描时间缩短。
通过以预定方式调制重复时间和反转时间，在保持恒定TR序列的信噪比和对比噪声比的同时，可有效缩短3D FLAIR的扫描时间。
