Parallel and nonparallel simultaneous multislice black-blood double inversion recovery techniques for vessel wall imaging
Parallel and nonparallel simultaneous multislice black-blood double inversion recovery techniques for vessel wall imaging
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DOI：
10.1002/jmri.20022
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发表时间：
2004-04-01
影响因子：
4.4
通讯作者：
Fayad, ZA
中科院分区：
文献类型：
--
作者：
Itskovich, VV;Mani, V;Fayad, ZA
目的：采用并行采集技术，同时采集多片黑血管壁成像，减少长时间的检查时间。材料和方法：开发了带弛豫增强（RARE）的dir快速采集技术，每次采集可同时成像多达10个切片，使用单个和多个180度反转脉冲。采用广义自校准部分平行采集（GRAPPA）成像，实现了板选择性反演多层DIR-RARE序列。建立四通道和八通道颈动脉线圈来测试这些序列。共研究了11名受试者。通过测量3例健康受试者主动脉图像的噪比（CNR）和信噪比（SNR）效率因子（SEF， SNR/单位时间/切片），确定最佳MR参数。在其余5名健康受试者和3名动脉粥样硬化患者的主动脉和颈动脉上运行DIR-RARE-GRAPPA序列，获得最佳参数（获取时间12-21秒）。结果：板选择性协议的sef显著高于切片选择性协议，DIR-RARE-GRAPPA协议的sef显著高于相应的非grappa协议（P < 0.05）。不同成像方案的CNR无显著差异。与单层DIR-2RARE序列相比，DIR-RARE-GRAPPA多层序列的时间改善了8.35倍。结论：使用这些方法，未来的MRI动脉粥样硬化斑块研究可以在更短的时间内完成。
Purpose: To reduce long examination times of black-blood vessel wall imaging by acquiring multiple slices simultaneously and by using parallel acquisition techniques.Materials and Methods: DIR-rapid acquisition with relaxation enhancement (RARE) techniques imaging up to 10 simultaneous slices per acquisition with single and multiple 180degrees-reinversion pulses were developed. A slab-selective reinversion multislice DIR-RARE sequence incorporating generalized autocalibrating partially parallel acquisitions (GRAPPA) imaging was implemented. Four-channel and eight-channel carotid coils were built to test these sequences. A total of 11 subjects were studied. Contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) efficiency factor (SEF, SNR/unit time/slice) were measured from aortic images of three healthy subjects to determine optimal MR parameters. The DIR-RARE-GRAPPA sequence was run on aortas and carotid arteries of the five remaining healthy subjects and three atherosclerotic patients with optimal parameters (acquisition times 12-21 seconds).Results: SEFs of slab-selective protocols were significantly higher than those of slice-selective protocols, and SEFs of DIR-RARE-GRAPPA protocols were significantly higher than corresponding non-GRAPPA protocols (P < 0.05). CNR was not significantly different for all imaging protocols. The DIR-RARE-GRAPPA multislice sequence showed 8.35-fold time improvement vs. single-slice DIR-2RARE sequence.Conclusion: Future MRI atherosclerotic plaque studies can be performed in substantially shorter times using these methods.