MRI-temperature mapping during ultrasound prostate ablation using fat for phase estimation.

Area of Science:

• Medical Imaging
• Biophysics
• Therapeutic Ultrasound

Background:

• Referenceless proton resonance frequency (PRF) shift thermometry offers motion-robust temperature monitoring during thermotherapy.
• Existing methods face challenges with background phase variations and applicator-induced distortions.

Purpose of the Study:

• To enhance referenceless PRF shift thermometry for improved accuracy in minimally invasive thermal therapies.
• To enable background phase estimation from surrounding fatty tissue.
• To develop a correction scheme for ultrasound applicator artifacts.

Main Methods:

• The study expanded referenceless PRF shift thermometry by incorporating background phase estimation from fatty tissue.
• A novel correction scheme was developed to mitigate temperature map distortions caused by the ultrasound applicator.
• The enhanced method was validated during transurethral ultrasound-guided thermal ablation of canine prostate.

Main Results:

• The enhanced referenceless PRF shift thermometry demonstrated robust temperature mapping.
• Successful background phase estimation from fatty tissue was achieved.
• The applicator correction scheme effectively reduced temperature map distortions.

Conclusions:

• Referenceless PRF shift thermometry, enhanced with fatty tissue background estimation and applicator correction, is a viable technique for accurate temperature monitoring during thermal ablation.
• This improved method holds promise for precise thermal therapy guidance.