Spectrally selective and interleaved water imaging and fat imaging (siWIFI)

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Medical Imaging
• Biomedical Engineering

Background:

• Accurate fat quantification is crucial for diagnosing and monitoring various medical conditions.
• Traditional MRI sequences can be susceptible to motion artifacts, compromising image quality and quantification accuracy.
• Developing motion-insensitive imaging techniques is essential for reliable in vivo measurements.

Purpose of the Study:

• To develop a novel MRI sequence, spectrally selective and interleaved water imaging and fat imaging (siWIFI), for independent water and fat image acquisition.
• To ensure the developed sequence is inherently insensitive to motion artifacts.
• To enable accurate in vivo fat fraction quantification.

Main Methods:

• The siWIFI sequence utilizes spectrally selective RF pulses for separate water and fat excitation.
• Interleaved acquisition ensures inherent coregistration of water and fat images.
• A radial sampling strategy and optional magnetization transfer (MT) preparation module were employed for artifact reduction and simultaneous fat fraction and MT ratio measurement.

Main Results:

• siWIFI demonstrated excellent correlation between phantom fat fraction measurements and known lipid concentrations (R² = 0.9995).
• In vivo fat fraction measurements using siWIFI were comparable to the vendor-provided IDEAL method.
• siWIFI exhibited reduced motion artifacts in knee and liver imaging compared to IDEAL, even without breath-holding.

Conclusions:

• The siWIFI sequence provides accurate and reliable water-fat imaging and quantification.
• Its inherent motion insensitivity makes it a valuable tool for clinical applications.
• The siWIFI framework supports simultaneous fat fraction and MT ratio mapping, enhancing its utility.