First experience with MR-guided focused ultrasound in the treatment of Parkinson's disease

Abstract

BackgroundRadiofrequency (RF) subthalamotomies have been proposed since the 1960s to treat patients suffering from Parkinson's disease (PD). Recently, the magnetic resonance (MR)-guided focused ultrasound technology (MRgFUS) offers the possibility to perform subthalamic thermocoagulations with reduced risks and optimized accuracy. We describe here the initial results of the MRgFUS pallidothalamic tractotomy (PTT), an anatomical and physiological update of the earlier subthalamotomies.MethodsThirteen consecutive patients suffering from chronic (mean disease duration 9.7 years) and therapy-resistant PD were treated unilaterally with an MRgFUS PTT. Primary relief assessment indicators were the score reduction of the Unified Parkinson Disease Rating Scale (UPDRS) and the patient estimation of global symptom relief (GSR) taken at 3 months follow-up. Final temperatures at target were between 52°C and 59°C. The MR examinations were performed before the treatment, 2 days and 3 months after it. The accuracy of the targeting was calculated on 2 days post-treatment MR pictures for each PTT lesion.ResultsThe first four patients received a PTT using the lesional parameters applied for thalamotomies. They experienced clear-cut recurrences at 3 months (mean UPDRS relief 7.6%, mean GSR 22.5%), and their MR showed no sign of thermal lesion in T2-weighted (T2w) images. As a consequence, the treatment protocol was adapted for the following nine patients by applying repetition of the final temperatures 4 to 5 times. That produced thermocoagulations of larger volumes (172 mm3 against 83 mm3 for the first four patients), which remained visible at 3 months on T2w images. These nine patients enjoyed a mean UPDRS reduction of 60.9% and a GSR of 56.7%, very close to the results obtained with radiofrequency lesioning. The targeting accuracy for the whole patient group was 0.5, 0.5, and 0.6 mm for the anteroposterior (AP), mediolateral (ML), and dorsoventral (DV) dimensions, respectively.ConclusionsThis study demonstrated the feasibility, safety, and accuracy of the MRgFUS PTT. To obtain similar results as the ones of RF PTT, it was necessary to integrate the fact that white matter, in this case, the pallidothalamic tract, requires repeated thermal exposition to achieve full lesioning and thus full therapeutic effect.

The Use of Magnetic Resonance Imaging-guided Focused Ultrasound in Movement Disorders—A Review

“…This study demonstrated that repeated application of energy allowed for more sustained effects with a 60.9% mean total Unified Parkinson's Disease Rating Scale (UPDRS) score reduction noted in the second group, versus 7.6% reduction in the first group at 3 months. 23 There were no procedure-related side effects reported in either group. Based on the Mini Mental Status Test and the Hospital Anxiety and Depression Scores, there was no change in mood or cognition pre and post procedure for either group.…”

The use of transcranial focused ultrasound in CNS diseases

“…Magara и соавт. [32] представили результаты лече-ния 13 пациентов с болезнью Паркинсона при помощи односторонней ультразвуковой паллидоталамической трактотомии. У первых 4 пациентов (1-я группа) целевая температура была достигнута однократно и на этом про-цедура была завершена.…”

“…Объем, локализация и МР-харак-теристики очагов, получаемых при ультразвуковой де-струкции, совпадают с таковыми при радиочастотной термоабляции [22,36,37]. При этом эффективность уль-тразвуковой деструкции представляется сопоставимой с эффективностью радиочастотной термоабляции, а также стимуляции глубинных структур [18,19,22,32,35,[38][39][40][41][42][43][44]. Из всех деструктивных методик ФУЗ представляется наи-более оптимальной, так как эта процедура, в отличие от прямой стереотаксической радиочастотной абляции, ис-ключает риски внутримозговых кровоизлияний, инфици-рования и др., и по сравнению с радиохирургическим ле-чением характеризуется возможностью физиологической верификации, предсказуемостью результата и быстрым развитием эффекта [19,[45][46][47].…”

Focused ultrasound in neurosurgery: a historical perspective

“…34 After some modifications to the treatment parameters, patients experienced an improvement of 60.9% in the UPDRS, comparable to published outcomes from radiofrequency ablation of this area. 44 Currently MRgFUS is approved for the treatment of parkinsonian tremor and dyskinesia in Europe and Israel, 68 and is currently undergoing several Phase 1 and 2 clinical trials in North America and Korea looking at a range of targets (clinical trial registration nos. NCT02252380, NCT0200324, and NCT02246374).…”