Magnetic Resonance Imaging-guided High-intensity Focused Ultrasound Applications in Pediatrics: Early Experience at Children's National Medical Center.

Magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) is a novel technology that integrates magnetic resonance imaging with therapeutic ultrasound. This unique approach provides a completely noninvasive method for precise thermal ablation of targeted tissues with real-time imaging feedback. Over the past 2 decades, MR-HIFU has shown clinical success in several adult applications ranging from treatment of painful bone metastases to uterine fibroids to prostate cancer and essential tremor. Although clinical experience in pediatrics is relatively small, the advantages of a completely noninvasive and radiation-free therapy are especially attractive to growing children. Unlike elderly patients, young children must deal with an entire lifetime of negative effects related to collateral tissue damage associated with invasive surgery, side effects of chemotherapy, and risk of secondary malignancy due to radiation exposure. These reasons provide a clear rationale and strong motivation to further advance clinical utility of MR-HIFU in pediatrics. We begin with an introduction to MR-HIFU technology and the clinical experience in adults. We then describe our early institutional experience in using MR-HIFU ablation to treat symptomatic benign, locally aggressive, and metastatic tumors in children and young adults. We also review some limitations and challenges encountered in treating pediatric patients and highlight additional pediatric applications which may be feasible in the near future.