Feasibility of magnetic resonance-guided high-intensity focused ultrasound treatment targeting distinct nodular lesions in neurofibromatosis type 1

Caitlin Tydings; Pavel Yarmolenko; Miriam Bornhorst; Eva Dombi; John Myseros; Robert Keating; James Bost; Karun Sharma; AeRang Kim

doi:10.1093/noajnl/vdab116

Feasibility of magnetic resonance-guided high-intensity focused ultrasound treatment targeting distinct nodular lesions in neurofibromatosis type 1

Neurooncol Adv. 2021 Aug 18;3(1):vdab116. doi: 10.1093/noajnl/vdab116. eCollection 2021 Jan-Dec.

Authors

Caitlin Tydings^{1

2}, Pavel Yarmolenko², Miriam Bornhorst^{1

3}, Eva Dombi⁴, John Myseros⁵, Robert Keating⁵, James Bost⁶, Karun Sharma^{2

7}, AeRang Kim^{1

2}

Affiliations

¹ Center for Cancer and Blood Disorders, Children's National Hospital, Washington, District of Columbia, USA.
² Sheikh Zayed Institute for Pediatric Surgical Innovation, Children's National Hospital, Washington, District of Columbia, USA.
³ Gilbert Neurofibromatosis Institute, Children's National Hospital, Washington, District of Columbia, USA.
⁴ National Cancer Institute, Pediatric Oncology Branch, National Institutes of Health, Bethesda, Maryland, USA.
⁵ Department of Neurosurgery, Children's National Hospital, Washington, District of Columbia, USA.
⁶ Department of Biostatistics and Study Methodology, Children's Research Institute, Washington, District of Columbia, USA.
⁷ Department of Radiology, Children's National Hospital, Washington, District of Columbia, USA.

Abstract

Background: Patients with Neurofibromatosis Type 1 (NF1) and plexiform neurofibromas (PN) often have radiographically diagnosed distinct nodular lesions (DNL) which can cause pain and weakness. Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) can precisely and accurately deliver heat to thermally ablate target tissue. The aim of this study is to evaluate whole-body MRIs from patients with NF1 and DNL, applying volumetrics and a consistent treatment planning approach to determine the feasibility of MR-HIFU ablation of DNL.

Methods: A retrospective review of whole-body MRI scans from patients with NF1 and PN from CNH and NCI was performed. DNL are defined as lesions >3 cm, distinct from PN and lacking the "central dot" feature. Criteria for MR-HIFU thermal ablation include target location 1-8 cm from skin surface; >1 cm from visible plexus, spinal canal, bladder, bowel, physis; and ability to ablate ≥50% of lesion volume. Lesions in skull and vertebral body were excluded.

Results: In 26 patients, 120 DNL were identified. The majority of DNL were located in an extremity (52.5%). Other sites included head/neck (7%), chest (13%), and abdomen/pelvis (28%). The predefined HIFU ablation criteria was not met for 47.5% of lesions (n = 57). The main limitation was proximity to a vital structure or organ (79%). Complete and partial HIFU ablation was feasible for 25% and 27.5% of lesions, respectively.

Conclusion: Based on imaging review of lesion location, technical considerations and ability to target lesions, thermal ablation with MR-HIFU may be a feasible noninvasive alternative for symptom management in patients with NF1 and symptomatic DNL.

Keywords: distinct nodular lesions; magnetic resonance-guided high-intensity focused ultrasound; neurofibromatosis type 1; targeted therapy.