Detecting High Intensity Focused Ultrasound Thermal Lesions Using T2-Weighted Fast Spin Echo Magnetic Resonance Imaging: An Ex Vivo Tissue Study

HIFU is a non-invasive thermal therapy treatment that uses heat to destroy cells and is used in conjunction with imaging guidance, e.g., MRI, for accurate targeting and treatment monitoring. T2W-FSE is the most commonly used MRI pulse sequence to detect thermal lesions as it provides good contrast. A drawback is the manifestation of artifacts and loss of spatial resolution due to the T2 decay. The IFT multiplication scheme aims to smooth out the signal modulation caused by the T2 decay by multiplying an IFT multiplication filter to the phase-encoding direction of k-space. Corrected MR images of HIFU thermal lesions using the narrow filter yielded the largest improvement of 13.83±2.49%, 17.04±2.25%, and 14.44±1.12% for lateral and axial spatial resolution, and lesion SNR, respectively, compared to the original image. The results indicate the potential of the IFT multiplication scheme as a method to improve HIFU thermal lesion detectability in MR images.