Shift of the Pyramidal Tract During Resection of the Intraaxial Brain Tumors Estimated by Intraoperative Diffusion-Weighted Imaging

Norihiko OZAWA; Yoshihiro MURAGAKI; Ryoichi NAKAMURA; Tomokatsu HORI; Hiroshi ISEKI

doi:10.2176/nmc.49.51

Original Articles

Shift of the Pyramidal Tract During Resection of the Intraaxial Brain Tumors Estimated by Intraoperative Diffusion-Weighted Imaging

Norihiko OZAWA, Yoshihiro MURAGAKI, Ryoichi NAKAMURA, Tomokatsu HORI, Hiroshi ISEKI

Author information

Norihiko OZAWA
Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University
MRI System Division, Hitachi Medical Corporation
Yoshihiro MURAGAKI
Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University
Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University
Ryoichi NAKAMURA
Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University
International Research and Educational Institute for Integrated Medical Sciences, Tokyo Women's Medical University
Department of Artificial Systems Science, Graduate School of Engineering, Chiba University
Tomokatsu HORI
Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University
Hiroshi ISEKI
Faculty of Advanced Techno-Surgery, Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University
Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University
International Research and Educational Institute for Integrated Medical Sciences, Tokyo Women's Medical University

Keywords: brain shift, pyramidal tract, functional mapping, diffusion-weighted magnetic resonance imaging, intraoperative magnetic resonance imaging, neuronavigation

JOURNAL OPEN ACCESS

2009 Volume 49 Issue 2 Pages 51-56

DOI https://doi.org/10.2176/nmc.49.51

Details

Abstract

The present study evaluated the shift of the pyramidal tract during resection of 17 proximal intraaxial brain tumors. In each case intraoperative diffusion-weighted (iDW) magnetic resonance imaging with a motion-probing gradient applied in the anteroposterior direction was performed using a scanner with a 0.3 T vertical magnetic field. The position of the white matter bundles containing the pyramidal tract was estimated on the coronal images before and after resection of the neoplasm, and both quantitative and directional evaluation of its displacement was done. In all cases iDW imaging provided visualization of the structure of interest. The magnitude of the pyramidal tract displacement due to removal of the neoplasm varied from 0.5 to 8.7 mm (mean 4.4 ± 2.5 mm) on the lesion side and from 0 to 3.6 mm (mean 1.3 ± 1.1 mm) on the normal side (p < 0.001). Tumor location in regards to the pyramidal tract was significantly associated with the direction of the pyramidal tract displacement (p < 0.05). Outward shift occurred in 10 out of 13 cases of the lateral neoplasms, whereas in all 4 superomedial tumors inward shift was marked. In conclusion, the direction of the pyramidal tract displacement during resection of the proximal intraaxial brain tumors is mainly determined by position of the neoplasm, but can be unpredictable in some cases, which necessitates use of subcortical brain mapping and intraoperative imaging, particularly iDW imaging with updated neuronavigation.

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