Acoustic radiation force imaging using a single-shot spiral readout.

Area of Science:

• Biomedical Imaging
• Ultrasound Technology
• Magnetic Resonance Imaging

Background:

• Focused ultrasound (FUS) enables precise thermal ablation.
• Monitoring tissue changes during ablation is crucial for treatment success.
• Current MR-ARFI methods are too slow for real-time guidance.

Purpose of the Study:

• Develop and validate a rapid MR-ARFI technique.
• Utilize a single-shot spiral readout for faster imaging.
• Enable real-time tissue displacement measurement for FUS guidance.

Main Methods:

• Employed a magnetic resonance guided FUS system.
• Used a 7 T MRI with a modified single-shot spiral readout and motion encoding gradients.
• Analyzed phase images to quantify local tissue displacement and assess thermal ablation effects.

Main Results:

• Achieved MR-ARFI imaging in one second, significantly faster than conventional methods.
• Detected and localized ARFI displacement in phantoms with <5% geometric distortion.
• Measured a 78% reduction in tissue displacement post-ablation in ex vivo chicken breast.

Conclusions:

• Rapid MR-ARFI with spiral readout is suitable for FUS guidance without causing thermal elevation.
• This technique allows rapid, accurate local tissue displacement measurements during thermal ablation.
• The method can potentially assess the efficacy of thermal ablation treatments.