Magnetic resonance guided focused ultrasound surgery. Ablation of soft tissue at bone-muscle interface in a porcine model.

BACKGROUND: Pain management treatments of patients with bone metastases have either efficacy problems or significant side effects. Percutaneous radiofrequency ablation has recently proved to be of palliative value. Magnetic resonance guided focused ultrasound surgery (MRgFUS) uses focused ultrasonic energy to non-invasively create a heat-coagulated lesion deep within the body in a controlled, accurate manner. The surgeon can monitor and control energy deposition in real time. This technology represents a potential treatment modality in oncological surgery. We investigated the ability of two MRgFUS methods to accurately and safely target and ablate soft tissue at its interface with bone. MATERIALS AND METHODS: Heat-ablated lesions were created by MRgFUS at the bone-muscle interface of 15 pigs. Two different methods of energy delivery were used. Temperature rise at the target adjacent to bone was monitored by real time MR thermal images. Results were evaluated by MRI (magnetic resonance imaging), nuclear scanning and by histopathological evaluation. RESULTS: Soft tissue lesion sizes by both methods were in the range of 1-2 cm in diameter. Targeting the focus 'behind' the bone, achieved the same result with a single sonication only. Follow up MRI and histopathological examination of all lesions showed focal damage at its interface with bone and localized damage to the outer cortex on the side closer to the targeted tissue. There was no damage to non-targeted tissue. CONCLUSION: MRgFUS by both energy deposition methods can be used to produce controlled well-localized damage to soft tissue in close proximity to bone, with minimal collateral damage.

Pregnancy and live birth after focused ultrasound surgery for symptomatic focal adenomyosis: a case report.

Adenomyosis is a benign disease whose symptoms mimic those of uterine leiomyoma. Hysterectomy is the treatment of choice; conservative surgery is difficult to perform and can damage the uterine structural integrity. We report the case of a 36-year-old woman who had difficulty conceiving because of profuse menometrorrhagia. An 84 cm3 uterine tumour was diagnosed on ultrasonography as leiomyoma, and conservative myomectomy was planned. Magnetic resonance imaging (MRI) corrected the diagnosis to focal adenomyosis. Magnetic resonance-guided focused ultrasound surgery (MRgFUS) destroyed a significant part of the tumour. Following an uncomplicated MRgFUS treatment, a non-perfused volume of 33 cm3 was measured. At 6 weeks, the patient experienced a significant reduction in menometrorrhagia and a marked decrease in tumour size (about 50%). She conceived spontaneously and, after an uneventful pregnancy, gave birth at term to a healthy infant via normal vaginal delivery. No structural uterine abnormality was detected after her delivery. This report highlights the difficult diagnosis and new therapeutic considerations of adenomyosis. MRgFUS seems to have the potential to precisely and effectively treat focal adenomyosis without damage to surrounding healthy myometrium, allowing for normal reproduction. Further studies are needed to assess the overall safety and long-term effectiveness of MRgFUS for the non-invasive treatment of adenomyosis.