Extracorporeal ablation of uterine fibroids with high-intensity focused ultrasound: imaging and histopathologic evaluation.

Objective: The purpose of this study was to evaluate the therapeutic efficacy of high-intensity focused ultrasound (HIFU) in the treatment of uterine fibroids by using imaging and histopathologic examination.

Methods: From May 2004 to June 2005, 119 consecutive patients with 187 uterine fibroids were treated with HIFU. Sixty-two fibroids received ultrasonographically guided needle puncture biopsy 1 week before and after HIFU treatment, respectively, to confirm the diagnosis and to assess the early therapeutic efficacy. Hematoxylin-eosin staining and electron microscopy were performed to characterize more subtle phenotypic changes to determine treatment success. Immediate therapeutic effects were assessed at follow-up with Doppler ultrasonography and computed tomography or magnetic resonance imaging. All patients were followed for 6 to 12 months to observe long-term therapeutic effects. Fibroid mean diameters, volumes, and reduction rates 1, 3, 6, and 12 months after HIFU treatment were calculated and compared with 1-way analysis of variance and Student-Newman-Keuls tests.

Results: No severe complications were observed after HIFU ablation. Fifty-one (82.3%) of 62 biopsy specimens revealed obvious signs of necrosis under light microscopy, and more subtle changes in cellular structure that indicated nonviability could be found in 60 specimens (96.8%) under electron microscopy. However, viable cells still could be found in 16 specimens (25.8%). Follow-up images showed absence or reduction of blood supply in the lesions after HIFU ablation. Median reductions in tumor size as a percentage of initial tumor volume at 1, 3, 6, and 12 months after HIFU treatment were 21.2%, 29.6%, 44.8%, and 48.7%, respectively.

Conclusions: Imaging and histopathologic evidence directly validate HIFU ablation as an effective treatment of uterine fibroids.