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K-t GRAPPA-accelerated 4D flow MRI of liver hemodynamics: influence of different acceleration factors on qualitative and quantitative assessment of blood flow.
- Source :
- MAGMA: Magnetic Resonance Materials in Physics, Biology & Medicine; Apr2015, Vol. 28 Issue 2, p149-159, 11p
- Publication Year :
- 2015
-
Abstract
- Objective: We sought to evaluate the feasibility of k-t parallel imaging for accelerated 4D flow MRI in the hepatic vascular system by investigating the impact of different acceleration factors. Materials and methods: k-t GRAPPA accelerated 4D flow MRI of the liver vasculature was evaluated in 16 healthy volunteers at 3T with acceleration factors R = 3, R = 5, and R = 8 (2.0 × 2.5 × 2.4 mm, TR = 82 ms), and R = 5 (TR = 41 ms); GRAPPA R = 2 was used as the reference standard. Qualitative flow analysis included grading of 3D streamlines and time-resolved particle traces. Quantitative evaluation assessed velocities, net flow, and wall shear stress (WSS). Results: Significant scan time savings were realized for all acceleration factors compared to standard GRAPPA R = 2 (21-71 %) ( p < 0.001). Quantification of velocities and net flow offered similar results between k-t GRAPPA R = 3 and R = 5 compared to standard GRAPPA R = 2. Significantly increased leakage artifacts and noise were seen between standard GRAPPA R = 2 and k-t GRAPPA R = 8 ( p < 0.001) with significant underestimation of peak velocities and WSS of up to 31 % in the hepatic arterial system ( p <0.05). WSS was significantly underestimated up to 13 % in all vessels of the portal venous system for k-t GRAPPA R = 5, while significantly higher values were observed for the same acceleration with higher temporal resolution in two veins ( p < 0.05). Conclusion: k-t acceleration of 4D flow MRI is feasible for liver hemodynamic assessment with acceleration factors R = 3 and R = 5 resulting in a scan time reduction of at least 40 % with similar quantitation of liver hemodynamics compared with GRAPPA R = 2. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09685243
- Volume :
- 28
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- MAGMA: Magnetic Resonance Materials in Physics, Biology & Medicine
- Publication Type :
- Academic Journal
- Accession number :
- 101894777
- Full Text :
- https://doi.org/10.1007/s10334-014-0456-1