Stepwise Dual-Target Magnetic Resonance–Guided Focused Ultrasound in Tremor-Dominant Parkinson Disease: A Feasibility Study

Abstract

Magnetic resonance-guided focused ultrasound (MRgFUS) has been applied successfully in treating refractory tremors in Parkinson disease (PD). It generates a precise thermal ablation in a specific nucleus or tract, such as ventral intermediate nucleus (VIM) or pallidothalamic tract (PTT). Despite a single lesion improving parts of the PD symptoms, the feasibility and efficacy of a stepwise dual-lesion in VIM and PTT are yet to be explored. Three patients with tremor-dominant PD (aged 60.7 ± 6.0 years) received dual-target MRgFUS treatment with a series of primary and secondary outcome measures. The VIM and PTT were navigated based on individual magnetic resonance imaging planning of the brain. The primary outcome measures were the off-status Clinical Rating Scale for Tremor and Unified Parkinson's Disease Rating Scale part III (UPDRS-III). The secondary outcome measures included UPDRS I, II, IV, Hohen and Yahr score, Neuropsychiatry Inventory, Quality of life in PD Rating Scale, Non-Motor Symptoms Scale, and Clinical Global Impression. The baseline data were compared with those acquired 1 day and 1 month following the treatment. The severity of tremor and motor deficits represented by Clinical Rating Scale for Tremor-part B and UPDRS III were significantly improved (P < 0.05 by nonparametric Mann-Whitney U tests) after dual-target ablations. The nonmotor symptoms investigated by UPDRS II and Non-Motor Symptoms Scale also showed significant improvement at the 1-day and 1-month follow-up. There was no adverse effect except temporary procedure-related headache and dizziness during the treatment. Stepwise dual-lesion targeting VIM and PTT is a safe and effective MRgFUS therapeutic strategy for patients with PD.