The impact of technical parameters on ablation volume during MR-guided focused ultrasound of desmoid tumors

Summary

The purpose of this study was to retrospectively review the magnetic resonance-guided focused ultrasound (MRgFUS) treatments of desmoid tumors at our institution to determine which technical treatment parameters contributed most significantly to the accumulation of thermal dose. We retrospectively reviewed data from MRgFUS treatments performed in histologically-confirmed desmoid tumors, over a period of 18 months. Nine-hundred thirty-six sonications were reviewed in 13 treatments. Accumulated dose per sonication was greatest for elongated sonications (0.96 cc ± 0.90) compared to short (0.88 ± 0.93 cc) and nominal (0.55 ± 0.70 cc) sonications, p < .001. 65.2% of short sonications resulted in high percentage ablations, compared to 46.0% of nominal and 35.1% of elongated sonications. Regarding dose efficacy, dose area contributed the greatest to this variability - 50.7% (45.5-54.8%), followed by distance - 16.6% (12.9-20.0%). A variety of sonication parameters significantly contributed to thermal ablation volume following MRgFUS of desmoid tumors, in reproducible patterns. This work can serve as the basis for future models working toward improved planning for MRgFUS treatments.