The Value of Tractography

Towards More Accurate Targeting in Deep Brain Stimulation?

Master thesis (2023)

Authors

A.J.M. Zwinkels Mechanical Engineering

Contributors

N.A. van der Gaag Leiden University Medical Center (supervisor 1)
F.M. Vos ImPhys/Computational Imaging - AS (supervisor 1)
Maria Fiorella Contarino Leiden University Medical Center (supervisor 2)
J. Harlaar Biomechatronics & Human-Machine Control - Mechanical, Maritime and Materials Engineering (supervisor 2)
Faculty
Mechanical Engineering
Copyright: © 2023 Anouk Zwinkels
Diffusion MRI Tractography Target localization Essential tremor Deep Brain Stimulation (DBS) Parkinson's Disease (PD)
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Published Date

26-09-2023

Language

English

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Faculty

Mechanical Engineering

Abstract

Introduction: Deep brain stimulation (DBS) is an important therapeutic option for various neurological diseases. For certain indications the optimal target cannot be identified on structural magnetic resonance imaging (MRI), but can be visualized with tractography. A recent improvement for clinical practice is the probabilistic tractography algorithm, providing superior results to the deterministic counterpart. However, it is suggested that clinical users are unfamiliar with the complex technology of this new approach, which might lead to missed potential of tractography in DBS-care. The overall aims of this thesis were threefold: to create an overview of the national landscape on the application of tractography, to narrow the gap between medicine and advanced technology in the application of tractography in DBS surgery planning, and to report potentialities and pitfalls of the implementation of tractography in a general hospital.

Methods: In the first part, a survey was conducted among Dutch DBS clinicians on the deployment of tractography. The survey consisted of 25 questions about the provision of DBS care, the use of tractography, the expert’s opinion and the respondent’s demographic characteristics. A comprehensive literature study is conducted in the second part. In the third part, an economic evaluation is performed by analyzing the costs and benefits of tractography. Guidelines are suggested based on literature and expert experience.

Results: Tractography is considered valuable for essential tremor (p<0.001) and not valuable for epilepsy (p=0.002) and chronic cluster headache (p=0.016). The majority uses deterministic approaches like DTI. Probabilistic users consider tractography more valuable than deterministic users (p=0.036). There is a heterogeneity in used image acquisition parameters and a lack of knowledge exist on technical background of tractography. The key elements of the technical principles of tractography are summarized, including diffusion weighted MRI, the concept of estimating the diffusion tensors, image acquisition parameters and tract reconstruction with the deterministic and probabilistic approach and quantitative measures.

Conclusion: Tractography is used by DBS clinicians with limited knowledge on the technical aspects. Generally the inferior deterministic approach is used without an (inter)nationally standardized protocol for image acquisition and tract reconstruction. A comprehensive explanation of the technical concepts and suggested practical guidelines should contribute to better application of this promising technology in DBS-care.