%0 Systematic Review %T Transcranial MR-Guided Focused Ultrasound and Hyperostosis Calvariae Diffusa: Case Report and Systematic Review of the Literature. %A Bernstock JD %A Torio EF %A Raghu ALB %A Chua M %A Chen JA %A Segar D %A Gupta S %A White PJ %A McDannold N %A Golby AJ %A Cosgrove GR %J Stereotact Funct Neurosurg %V 100 %N 5 %D 2022 %M 36521432 %F 1.643 %R 10.1159/000527232 %X We describe a 74-year-old male with intractable essential tremor (ET) and hyperostosis calvariae diffusa who was unsuccessfully treated with magnetic resonance-guided focused ultrasound (MRgFUS). A computed tomography performed prior to the procedure demonstrated a skull density ratio (SDR) of 0.37 and tricortical hyperostosis calvariae diffusa. No lesion was evident on post-MRgFUS MRI, and no improvement in the patient's hand tremor was noted clinically. We systematically reviewed the literature to understand outcomes for those patients with hyperostosis who have undergone MRgFUS. A comprehensive literature search using the PubMed, Cochrane, and Google Scholar databases identified 3 ET patients with hyperostosis who failed treatment with MRgFUS. Clinical findings, skull characteristics, treatment parameters, and outcomes were summarized, demonstrating different patterns/degrees of bicortical hyperostosis and variable SDRs (i.e., from 0.38 to ≥0.45). Although we have successfully treated patients with bicortical hyperostosis frontalis interna (n = 50), tricortical hyperostosis calvariae diffusa appears to be a contraindication for MRgFUS despite acceptable SDRs.