Faserbahndarstellung im adulten menschlichen Gehirn mit der Diffusions-Tensor-Bildgebung am 3.0-Tesla-Tomographen : Methodenentwicklung, Anwendungsleitfaden, Atlas und vergleichende Studie

摘要

OBJECTIVE: Diffusion tensor imaging (DTI) is a promising technique and offers a unique insight into white matter anatomy in vivo. Nevertheless, this technique is subject to several restrictions and the image qualitiy is often not sufficient for the routine use in preoperative planning and intraoperative neuronavigation. Neurosurgeons who want to apply DTI fiber tract information to the planning of neurosurgical procedures need precise anatomical information concerning the location and course of fiber tracts in a 3-D space. Here, it is essential to visualize the entire extension, the “3-D envelope” of a specific fiber tract. The aim of our present study was to develop simple and reproducible strategies for 12 major white fiber tracts which enable especially clinicians to track a variety of fibers with low effort in a short time but with high anatomical precision. Furthermore, we acquired DTI-MR data of two patients with brain tumors to demonstrate the relevance of the improved results for the corticospinal tract. METHODS: We performed single-shot diffusion weighted spin-echo EPI sequences on 10 healthy subjects using a 3.0 Tesla clinical MR-scanner. 32 gradient axes were measured and additional T1-weighted magnetization prepared 3-D turbo fast-field gradient echo (TFE) sequences were acquired for anatomical reference. After distortion correction, fiber tracking was performed with Stealth DTI® (V1.1 fiber tracking module, developed by Mercury Computer Systems for Medtronic Neuronavigation, Louisville, Colorado, USA). We delineated start regions for tracking within the subcortical white matter in about 10 consecutive slices and obtained a complex “volume of interest” (VOI). After post-processing of the acquired fiber tracts, interindividual and interhemispherical variances in volume and sex could be analyzed.RESULTS AND CONCLUSIONS: We were able to present a considerable benefit concerning anatomical accuracy by optimizing tracking procedures and by enhancing and simplifying working steps. For the first time the corticospinal tract is displayed in its entire extension, including lateral aspects. This fiber tract, as well as the arcuate fascicle, show a significant interhemispherical asymmetry. Furthermore, this study can provide a guideline both for neuroanatomical basic research and for clinical applications. The findings for the correct and complete corticospinal tract are a crucial prerequisite for a valuable neurosurgical implementation of the DTI technique as clearly demonstrated by the results of our clinical cases.