Comparison of diffusion tensor imaging tractography of language tracts and intraoperative subcortical stimulations.

Delphine Leclercq, Hugues Duffau, Christine Delmaire, Laurent Capelle, Peggy Gatignol, Mathieu Ducros, Jacques Chiras, Stéphane Lehéricy
Journal of Neurosurgery. 2010-03-01; 112(3): 503-511
DOI: 10.3171/2009.8.jns09558

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1. J Neurosurg. 2010 Mar;112(3):503-11. doi: 10.3171/2009.8.JNS09558.

Comparison of diffusion tensor imaging tractography of language tracts and
intraoperative subcortical stimulations.

Leclercq D(1), Duffau H, Delmaire C, Capelle L, Gatignol P, Ducros M, Chiras J,
Lehéricy S.

Author information:
(1)Department of Neuroradiology, Groupe Hospitalier Pitié-Salpêtrière, Université
Pierre et Marie Curie, Paris, France.

OBJECT: Diffusion tensor (DT) imaging tractography is increasingly used to map
fiber tracts in patients with surgical brain lesions to reduce the risk of
postoperative functional deficit. There are few validation studies of DT imaging
tractography in these patients. The aim of this study was to compare DT imaging
tractography of language fiber tracts by using intraoperative subcortical
electrical stimulations.
METHODS: The authors included 10 patients with low-grade gliomas or dysplasia
located in language areas. The MR imaging examination included 3D T1-weighted
images for anatomical coregistration, FLAIR, and DT images. Diffusion tensors and
fiber tracts were calculated using in-house software. Four tracts were
reconstructed in each patient including the arcuate fasciculus, the inferior
occipitofrontal fasciculus, and 2 premotor fasciculi (the subcallosal medialis
fiber tract and cortical fibers originating from the medial and lateral premotor
areas). The authors compared fiber tracts reconstructed using DT imaging with
those evidenced using intraoperative subcortical language mapping.
RESULTS: Seventeen (81%) of 21 positive stimulations were concordant with DT
imaging fiber bundles (located within 6 mm of a fiber tract). Four positive
stimulations were not located in the vicinity of a DT imaging fiber tract.
Stimulations of the arcuate fasciculus mostly induced articulatory and
phonemic/syntactic disorders and less frequently semantic paraphasias.
Stimulations of the inferior occipitofrontal fasciculus induced semantic
paraphasias. Stimulations of the premotor-related fasciculi induced dysarthria
and articulatory planning deficit.
CONCLUSIONS: There was a good correspondence between positive stimulation sites
and fiber tracts, suggesting that DT imaging fiber tracking is a reliable
technique but not yet optimal to map language tracts in patients with brain
lesions. Negative tractography does not rule out the persistence of a fiber
tract, especially when invaded by the tumor. Stimulations of the different tracts
induced variable language disorders that were specific to each fiber tract.

DOI: 10.3171/2009.8.JNS09558
PMID: 19747052 [Indexed for MEDLINE]

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