Essential tremor (ET) is the most common movement disorder globally, affecting over a million individuals in the UK alone. It may present as an isolated condition or alongside other neurological diagnoses, such as Parkinson’s disease. ET is typically characterised by involuntary, rhythmic tremors that manifest during action – most commonly affecting the hands – and can significantly impair a patient’s ability to carry out everyday tasks, such as eating, writing or using electronic devices.
Conventional management pathway
First-line management remains pharmacological, with beta-blockers (e.g. propranolol) and anticonvulsants (e.g. primidone) being the most commonly prescribed. However, these agents have limited efficacy, with only 50% of patients achieving meaningful symptom relief. Side effects, such as drowsiness, dizziness, fatigue, bradycardia and balance issues, may limit long-term use.
Patients’ refractory to or intolerant of medical therapy may be considered for surgical interventions, including deep brain stimulation (DBS) or radiofrequency ablation (RFA). While effective, both options require invasive procedures, with DBS involving permanent intracranial hardware.
MR-guided Focused Ultrasound (MRgFUS)
MRgFUS offers a non-invasive alternative that is increasingly recognised as a transformative option for suitable ET patients. The technique, which is approved by NICE and commissioned by the NHS in two centres in England, uses high-intensity ultrasound beams, guided by MRI, to ablate a precise target within the ventral intermediate nucleus (VIM) of the thalamus. This results in a small, permanent lesion that disrupts tremorgenic neural pathways – without the need for anaesthesia, incisions or implanted devices.
Outcomes from clinical studies report an average 76.5% reduction in tremor severity. Improvements are often immediate and can be sustained for at least five years post-procedure as demonstrated in a study of patients at 4 and 5-year posttreatment. While not curative, MRgFUS can significantly enhance functional independence and quality of life.
Research undertaken by the team of world-leading neurosurgeons from Queen Square Imaging Centre has unveiled a breakthrough imaging technique that significantly enhances the precision and outcomes of MRgFUS. The study published in The BMJ Neurology Open marks the first clinical use of FAT1 imaging to guide focused ultrasound treatment for essential tremor. Traditionally, clinicians have relied on generalised brain maps to estimate the location of the target area deep within the brain – the Ventral Intermediate Nucleus (Vim) – which is extremely small and hard to visualise on standard MRI scans. FAT1 imaging overcomes this by giving surgeons a clear, direct view of the individual patient’s Vim, enabling treatment to be far more precise.
Eligibility criteria
MRgFUS should be considered in patients who meet the following criteria:
- Diagnosed with essential tremor refractory to medication
- Unable to tolerate side effects of first-line pharmacological treatments
- Experiencing functional impairment in daily living due to tremor e.g. eating, writing or social interaction
Contraindications to MRgFUS may include:
- Presence of non-MRI-compatible metal implants, fragments or medical devices. However, our imaging expertise allows us to consider and assess all patients, so it isn’t always necessarily the case that patients with implants or devices will be unsuitable.
- Significant speech or gait impairment, or evidence of cognitive decline
- Extensive scalp scarring (which may interfere with ultrasound transmission)
- Inability to discontinue anticoagulant therapy peri-procedurally
- Severe claustrophobia or inability to tolerate MRI scanning
Referral and assessment
All prospective candidates undergo a thorough multidisciplinary evaluation at Queen Square Imaging Centre to confirm diagnosis and determine suitability. Where appropriate, patients will be referred for neuroimaging for pre-treatment planning using advanced tractography-based targeting techniques (FAT1) to optimise outcomes and safety.
Raising awareness
Despite growing evidence of its effectiveness, MRgFUS remains underutilised and there are long waiting periods for the treatment on the NHS. With over 25,000+ patients already treated worldwide, including high-profile individuals such as Lord Julian Fellowes, there is a clear opportunity to expand access to this life-enhancing technology.
For referrals or to discuss a patient case, please contact Queen Square Imaging Centre.
