RATIONALE AND OBJECTIVES: To investigate the response after magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) treatment of uterine fibroids (UF) using a three-dimensional (3D) quantification of total and enhancing lesion volume (TLV and ELV, respectively) on contrast-enhanced MRI (ceMRI) scans.METHODS AND MATERIALS: In a total of 24 patients, ceMRI scans were obtained at baseline and 24 hours, and 6, 12, and 24 months after MRgHIFU treatment. The dominant lesion was assessed using a semiautomatic quantitative 3D segmentation technique. Agreement between software-assisted and manual measurements was then analyzed using a linear regression model. Patients were classified as responders (R) or nonresponders (NR) on the basis of their symptom report after 6 months. Statistical analysis included the paired t-test and Mann-Whitney test.RESULTS: Preprocedurally, the median TLV and ELV were 263.74 cm(3) (30.45-689.56 cm(3)) and 210.13 cm(3) (14.43-689.53 cm(3)), respectively. The 6-month follow-up demonstrated a reduction of TLV in 21 patients (87.5%) with a median TLV of 171.7 cm(3) (8.5-791.2 cm(3); P < .0001). TLV remained stable with significant differences compared to baseline (P < .001 and P = .047 after 12 and 24 months). A reduction of ELV was apparent in 16 patients (66.6%) with a median ELV of 158.91 cm(3) (8.55-779.61 cm(3)) after 6 months (P = .065). Three-dimensional quantification and manual measurements showed strong intermethod agreement for fibroid volumes (R(2) = .889 and .917) but greater discrepancy for enhancement calculations (R(2) = .659 and .419) at baseline and 6 months. No significant differences in TLV or ELV were observed between clinical R (n = 15) and NR (n = 3).CONCLUSIONS: The 3D assessment has proven feasible and accurate in the quantification of fibroid response to MRgHIFU. Contrary to ELV, changes in TLV may be representative of the clinical outcome.
Adult Cohort Studies