Non-contrast-enhanced abdominal MRA at 3 T using velocity-selective pulse trains

Area of Science:

• Magnetic Resonance Imaging
• Vascular Imaging
• Medical Physics

Background:

• Noncontrast-enhanced abdominal MR arteriography (MRA) traditionally uses spatially selective inversion (SSI) pulses, which are limited in spatial coverage due to sensitivity to slow arterial flow.
• Velocity-selective techniques, such as velocity-selective inversion (VSI) and velocity-selective saturation (VSS), have shown promise in preserving arterial signal and suppressing static tissue, respectively.

Purpose of the Study:

• To develop and evaluate an abdominal MRA protocol with large spatial coverage at 3 Tesla using advanced velocity-selective pulse trains.
• To compare the performance of different velocity-selective preparations (VSS, SSI+VSS, VSI+VSS) for abdominal MRA.

Main Methods:

• Multiple velocity-selective MRA protocols employing different sequence modules and 3D acquisition methods were evaluated.
• Sequences including VSS only, SSI+VSS, and VSI+VSS preparations were compared in healthy volunteers.
• Quantitative analysis of relative signal and contrast ratios of vascular segments was performed against MRA without preparations.

Main Results:

• Both SSI+VSS and VSI+VSS preparations achieved high artery-to-tissue and artery-to-vein contrast ratios superior to the aortic bifurcation.
• The VSI+VSS sequence demonstrated superior signal in the bilateral iliac arteries compared to SSI+VSS, highlighting its benefit for distal branch imaging.

Conclusions:

• The feasibility of noncontrast 3D MR abdominal arteriography with large spatial coverage was successfully demonstrated in healthy volunteers.
• Combining velocity-selective saturation (VSS) pulse trains with either spatially selective inversion (SSI) or velocity-selective inversion (VSI) pulses provides effective abdominal MRA at 3 T.