Concurrent water T₂ and fat fraction mapping of the breast using the radial gradient and spin echo (RADGRASE) pulse...

Area of Science:

• Magnetic Resonance Imaging
• Biomedical Engineering
• Radiology

Background:

• Accurate assessment of breast tissue composition, including fat fraction (FF) and water T2 (T2w), is crucial for understanding tissue changes.
• Existing MRI techniques may face challenges in simultaneously quantifying both FF and T2w, especially in fatty breast tissues.

Purpose of the Study:

• To develop and evaluate an efficient radial gradient- and spin-echo (RADGRASE) pulse sequence and reconstruction algorithm.
• To enable concurrent measurement of proton-density weighted fat fraction (FF) and water component T2 (T2w) in breast tissues.
• To assess the utility of RADGRASE for detecting physiological and clinical changes in breast tissue.

Main Methods:

• Implementation of a novel RADGRASE pulse sequence and reconstruction algorithm.
• Validation using oil/gel phantoms with varying FF values (0.1-0.7).
• In vivo assessment in healthy volunteers and a cohort of patients taking tamoxifen.

Main Results:

• Successful estimation of T2w in breast tissues across a wide range of FF values.
• In vivo T2w mapping correlated well with fat-suppressed T2 values.
• RADGRASE detected significant T2w changes during the menstrual cycle (18-29 ms higher in luteal phase).
• A positive correlation between FF parameter Frac50 and T2w was observed in premenopausal patients on tamoxifen (p=0.035).

Conclusions:

• The RADGRASE technique efficiently and simultaneously maps FF and T2w in breast tissues.
• RADGRASE demonstrates sensitivity to physiological changes in breast tissue.
• The technique holds potential for clinical applications in studying breast tissue alterations.