Ker Tang (United Kingdom)
Author Of 1 Presentation
DETERMINISTIC TRACTOGRAPHY-BASED VERSUS INDIRECT-TARGETING MAGNETIC RESONANCE-GUIDED FOCUSSED ULTRASOUND TREATMENT OF MEDICATION-REFRACTORY ESSENTIAL TREMOR: 3-YEAR RESULTS OF A PROSPECTIVE COHORT STUDY
- Fan Cheng (United Kingdom)
Abstract
Background and Aims:
Successful magnetic resonance-guided focussed-ultrasound thalamotomy (MRgFUS) for medication-refractory essential tremor (ET) requires precise targeting of the thalamic ventrointermediate (VIM) nucleus. Diffusion-tensor imaging (DTI)-tractography localises VIM more accurately than standard indirect-targeting, although outcome-comparisons are limited. We prospectively evaluated deterministic tractography-based targeting and indirect-targeting MRgFUS outcomes in medication-refractory ET over 3-years.
Methods:
136 ET patients refractory to ≥3 medications with significant dominant-hand tremor were included (2 centres). 58 received tractography-based MRgFUS. 78 received indirect-targeting MRgFUS. All tractography-based patients underwent pre-treatment 3T-MRI, 3-tract deterministic DTI-tractography (targeting dentatorubrothalamic, pyramidal and somatosensory tracts) for contralateral VIM localisation (Brainlab iPlan), and indirect-targeting for VIM location comparison, before tractography-based direct-targeting MRgFUS. Indirect-targeting patient outcomes were correlated with overlap between MRgFUS-lesion and tractographic region-of-interest retrospectively-derived from pre-treatment DTI (Spearman’s rank). Total and hand tremor (Clinical Rating Scale for Tremor [CRST] total and A+B subscores), quality-of-life (QUEST score) and adverse events (AEs) were independently-compared 3-monthly for 3-years.
Results:
Mean CRST total, A+B, and QUEST scores improved post-MRgFUS from similar baselines in both groups (3-year: tractography -38.9,-12.8,-31.8; indirect-targeting -30.6,-10.0,-23.9,p<0.0001). Tractography-group had significantly-greater improvements at all timepoints (3-year mean change from baseline intergroup difference: CRST -6.2,p<0.0001; CRST-A+B -1.4,p=0.0015; QUEST -5.2,p=0.0046) (Table1–3). Anteroposterior coordinate in tractography-group differed significantly from indirect targeting-generated coordinate (7.7±0.8 vs 6.3±0.2mm,p<0.001). In indirect-targeting group, region-of-interest and lesion overlap correlated with greater CRST percentage-reduction (r=-0.732,-0.768,-0.814 at 1, 2, 3-years,p<0.03). Tractography-group had non-significantly reduced AE rate.
Conclusions:
In the largest prospective study with longest follow-up to-date, tractography-based MRgFUS demonstrates superior long-term efficacy, VIM-targeting accuracy and quality-of-life improvement over indirect-targeting MRgFUS for medication-refractory ET.