The Efficacy of Bisphosphonate to Increase the Skull Density Ratio of MRI-guided Focused Ultrasound Candidates with Brain Disorders

Background: Skull density ratio (SDR) is one of the key factors for the success of MRI-guided focused ultrasound (MRgFUS) treatment for brain diseases. We examined the efficacy of alendronate (Aln) to improve a SDR value. Materials and Methods: The subjects were 6 Parkinson’s disease patients (2 men, 4 women, 70.7 ± 7.7 years old) and 1 essential tremor patient (1 man, 81 years old). Despite of desire to MRgFUS treatment, we could not schedule their treatments because their SDR values were too low. As they coexisted with untreated osteoporosis, we administered 35 mg of Aln weekly and followed their SDR values every 3 months. Results: The SDR value elevated in 4 patients following the administration of Aln and we could perform MRgFUS treatment successfully. No adverse reactions related with Aln were observed. Conclusion: Although it will take several months, Aln may be a useful option for MRgFUS candidates with a low SDR value.