Perfusion volume correlates, percentage of involution, and clinical efficacy at diverse follow-up survey times after MR-guided focused ultrasound surgery in uterine fibroids: first report in a Mexican mestizo population.

Objectives: To evaluate the clinical efficacy of magnetic resonance-guided focused ultrasound surgery in a Mexican mestizo population.

Methods: This retrospective study included 159 women (mean age 37 ± 6.4 years, range 22-53 years) from 2008 to 2010. Two hundred sixty-eight symptomatic uterine fibroids were treated using MR-guided focused ultrasound surgery. Parameters included initial perfused volume, final perfused volume, non-perfused volume (NPV), and treated volume ratio (TVR). Follow-up up to 15 months assessed treatment efficacy and symptomatic relief. Non-parametric statistics and the Kaplan-Meier method were performed.

Results: T2-weighted hypointense fibroids showed a frequency of 93.6%; isointense and hyperintense fibroids had frequencies of 5.60 and 1.1%. There was a negative correlation between NPV and age (r = -0.083, p = 0.307) and treatment time (r = -0.253, p = 0.001). Median TVR was 96.0% in small fibroids and 76.5% in large fibroids. Involution of 50% and 80% was achieved at months 6-7 and month 11, respectively. Relief of symptoms was significant (p < 0.05).

Conclusions: Our data show that higher TVR attained immediately post-treatment of MRgFUS favours higher involution percentages at follow-up; however, careful patient selection and use of pretreatment imaging are important components for predicting success using MR-guided focused ultrasound surgery.

Key Points: • Type 1 fibroids were the most common (93.2%). • Age and treated volume were not correlated (r s   = -0.215, p = 0.165). • Small fibroids achieved a higher treated volume than large (96.0% vs. 76.5%). • A 50% involution was achieved at 6-month follow-up for type-1 fibroid. • A decrease of 80% was reached at 11 months for type-1 fibroids.