期刊
MAGNETIC RESONANCE IMAGING
卷 33, 期 9, 页码 1043-1050出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.mri.2015.07.002
关键词
Segmented TOF; 7T; Venous suppression; SAR; MR angiography
资金
- Ministry of Science and Technology of China Grants [2012CB825505, 2015CB351701]
- National Nature Science Foundation of China Grant [91132302]
- Chinese Academy of Sciences Strategic Priority Research Program B Grants [XDB02010100, XDB02050001]
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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