A fast referenceless PRFS-based MR thermometry by phase finite difference.

Area of Science:

• Medical Physics
• Biomedical Engineering
• Radiology

Background:

• Proton resonance frequency shift-based MR thermometry is crucial for thermotherapy but sensitive to motion.
• Existing referenceless methods often require time-consuming phase unwrapping.
• Phase artifacts can compromise the accuracy of MR thermometry.

Purpose of the Study:

• To develop a novel referenceless MR thermometry method that bypasses phase unwrapping.
• To enhance temperature monitoring accuracy in thermotherapy.
• To provide a computationally efficient solution for real-time temperature monitoring.

Main Methods:

• A referenceless MR thermometry technique utilizing phase finite difference was developed.
• The method incorporates perimeter data for accurate baseline phase extrapolation.
• It avoids phase unwrapping, unlike previous approaches.

Main Results:

• The proposed method achieved lower root-mean-square temperature errors (0.35°C, 1.02°C, 1.73°C) compared to the phase gradient method (0.83°C, 2.81°C, 3.76°C) in simulations, in vivo, and ex vivo experiments.
• It demonstrated slightly improved accuracy over the original referenceless MR thermometry.
• The method is computationally efficient, processing images in approximately 0.1 seconds.

Conclusions:

• The phase finite difference-based referenceless MR thermometry method offers improved accuracy and efficiency.
• It effectively mitigates artifacts and eliminates the need for phase unwrapping.
• This technique is well-suited for real-time temperature monitoring during thermotherapy.