Magnetization transfer in fatty and low-fat livers

Area of Science:

• Biomedical Imaging
• Magnetic Resonance Imaging
• Biophysics

Background:

• Proton relaxation parameters in liver tissue are crucial for understanding tissue composition.
• Magnetization transfer (MT) is a technique sensitive to macromolecular content.
• Low-field MRI presents challenges in accurately quantifying these parameters due to potential confounding factors like fat.

Purpose of the Study:

• To investigate the relationship between protein concentration and proton relaxation parameters in liver tissue using magnetization transfer at 0.1 T.
• To evaluate the influence of fat content on these measured parameters.
• To assess the efficacy of fat/water separation techniques for improving accuracy in low-field liver imaging.

Main Methods:

• Magnetization transfer (MT) imaging was performed on liver tissue at 0.1 Tesla.
• Pig liver (low-fat) and burbot liver (fatty) were used as tissue models.
• A specialized fat/water separation method was employed to isolate water signal contributions.

Main Results:

• In low-fat liver tissue, the magnetization transfer rate (Rwm) showed a significant linear correlation with total protein concentration (p = 0.0086).
• In fatty liver tissue, relaxation parameters did not correlate well with protein concentration prior to fat/water separation.
• Following fat/water separation, water-based relaxation times (T1, T1w), Rwm, and magnetization transfer contrast (MTC) significantly increased.

Conclusions:

• Protein concentration significantly influences magnetization transfer parameters in low-fat liver tissue.
• The presence of fat in liver tissue substantially affects the measured magnetization transfer parameters.
• Fat/water separation is essential for accurate assessment of magnetization transfer in fatty liver tissue at low field strengths.