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Changes In The Cerebello-thalamo-cortical Network After MR-guided Focused Ultrasound Thalamotomy. Brain connectivity Thaler, C., Tian, Q., WIntermark, M., Ghanouni, P., Halpern, C., Henderson, J., Airan, R., Zeineh, M., Goubran, M., Leuze, C., Fiehler, J., Butts Pauly, K., McNab, J. A. 2022

Abstract

Object In recent years, transcranial MR-guided focused ultrasound (tcMRgFUS) has been established as a potential treatment option for movement disorders, including essential tremor. So far, however, little is known about the impact of tcMRgFUS on structural connectivity. The objective of this study was to detect microstructural changes in tremor- and motor-related white matter tracts in essential tremor patients treated with tcMRgFUS thalamotomy. Methods Eleven patients diagnosed with essential tremor were enrolled in this tcMRgFUS thalamotomy study. For each patient, 3T MRI including structural and diffusion MRI were acquired and the Clinical Rating Scale for Tremor was assessed prior to the procedure as well as one year after the treatment. Diffusion MRI tractography was performed to identify the cerebello-thalamo-cortical tract (CTCT), the medial lemniscus (ML) and the corticospinal tract (CST) in both hemispheres on pre-treatment data. Pre-treatment tractography results were co-registered to post-treatment diffusion data. Diffusion tensor imaging (DTI) metrics, including fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD), were averaged across the tracts in the pre- and post-treatment data. Results The mean value of tract-specific DTI metrics changed significantly within the thalamic lesion and in the CTCT on the treated side (p<0.05). Changes of DTI-derived indices within the CTCT correlated well with lesion overlap (FA: r=-0.54, p=0.04; MD: r=0.57, p=0.04); RD: r=0.67, p=0.036). Furthermore, a trend was seen for the correlation between changes of DTI-derived indices within the CTCT and clinical improvement (FA: r=0.58; p=0.062; MD: r=-0.52, p=0.64; RD: r=-0.61 p=0.090). Conclusions Microstructural changes were detected within the CTCT after tcMRgFUS and these changes correlated well with lesion-tract overlap. Our results show that diffusion MRI is able to detect the microstructural effects of tcMRgFUS, thereby further elucidating the treatment mechanism and ultimately to improve targeting prospectively.

View details for DOI 10.1089/brain.2021.0157

View details for PubMedID 35678063