Multislice perfusion of the kidneys using parallel imaging: image acquisition and analysis strategies

Area of Science:

• Medical Imaging
• Nephrology
• Physiology

Background:

• Arterial spin labeling (ASL) is a non-invasive MRI technique for measuring tissue perfusion.
• Respiratory motion presents a significant challenge for ASL, particularly in abdominal organs like the kidneys, due to sequential subtraction methods.
• Optimizing ASL acquisition strategies is crucial for accurate kidney perfusion assessment.

Purpose of the Study:

• To evaluate the impact of different breathing strategies on kidney perfusion mapping using ASL.
• To assess the effectiveness of post-acquisition image registration for motion correction in ASL.
• To investigate the role of background suppression in kidney ASL.

Main Methods:

• Flow-sensitive alternating inversion recovery (FAIR) ASL with parallel imaging was employed for kidney perfusion mapping.
• Breathing strategies including free breathing, respiratory-triggered, and breath-hold were compared.
• Image registration algorithms were applied for post-acquisition motion correction.
• Perfusion rates were quantified before and after motion correction.

Main Results:

• Post-acquisition image realignment significantly improved visual quality and perfusion quantification.
• Free-breathing acquisitions with movement correction are feasible, reducing overall acquisition time and improving patient comfort.
• Background suppression in ASL reduced the perfusion signal-to-noise ratio and led to underestimation of perfusion.

Conclusions:

• Post-acquisition motion correction is essential for reliable kidney perfusion quantification with ASL.
• Free-breathing ASL with movement correction offers a practical and efficient approach for clinical applications.
• Background suppression should be used cautiously in kidney ASL due to its potential negative impact on signal and quantification.