摘要: Purpose: Time-of-flight (TOF) MR angiography has an advantage of contrast and resolution in ultra-high field (7 T) MRI systems. However, increased specific absorption rate (SAR) prohibits the application of spatial saturation band, leading to venous contamination in maximum intensity projection (MIP) images. Methods: A segmented k-space filling scheme with sparse venous saturation pulses was developed for 7 T TOF-MRA. The effectiveness of the segmented TOF sequence was verified by Bloch equation simulation and experiments on 3 T. The protocol on 7 T was optimized and applied for healthy volunteers and patients with vascular diseases. Results: Segmented TOF achieved equivalent contrast and venous suppression effect as conventional methods, while SAR values had a remarkable reduction and obeyed the limit of a 7 T MRI system. The decreased number of saturation pulses allowed shorter acquisition time than existing solutions. The comparison of segmented TOF and conventional TOF revealed flow direction in vascular diseases. Conclusion: Segmented TOF is proved to be a time-efficient way to achieve high-resolution angiograms without venous contamination at ultra-high field. The sequence holds strong promise for non-contrast clinical diagnosis on cerebrovascular diseases. (C) 2015 Elsevier Inc. All rights reserved.
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期刊:
MAGNETIC RESONANCE IMAGING
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分类:
生物学
>>
生物物理学
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引用:
ChinaXiv:201605.01416
(或此版本
ChinaXiv:201605.01416V1)
DOI:10.12074/201605.01416V1
CSTR:32003.36.ChinaXiv.201605.01416.V1
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Zhang, Zihao,Zuo, Zhentao,Wang, Bo,Wei, Ning,Xue, Rong,Zhang, Zihao,Wei, Ning,Deng, Xiaofeng,Zhao, Jizong,Weng, Dehe,An, Jing,Xue, Rong.(2016).Segmented TOF at 7 T MRI: Technique and clinical applications.中国科学院科技论文预发布平台.[ChinaXiv:201605.01416]
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