Temporal lobe association fiber tractography as compared to histology and dissection

To compare the temporal lobe white matter fiber bundles obtained by diffusion tensor imaging-based tractography to that by histology and dissection, and to study the interindividual variability of the obtained tracts.

DTI (diffusion tensor imaging) acquisitions (30 directions) were obtained from nine healthy volunteers. Imaging post-processing was performed with FSL (FMRIB Software Library) software. Uncinate fasciculus, longitudinal inferior fasciculus and optic radiations were tracked after positioning of the region of interest (ROI) in predetermined anatomical landmarks. Histological data were obtained by cutting 15 µm coronal sections in one left brain hemisphere and staining with modified Heidenhain-Woelcke myelin stain. Dissection was performed on the left brain hemisphere prepared in accordance with the Klingler method. Tractography of each bundle was compared to histology and dissection data. To highlight the interindividual variability of the considered fiber tracts, all the images were affinely registered on an arbitrarily chosen reference image by considering the B0 images. Fiber tracts were then warped according to the corresponding estimated transformation and an average fiber tract image was then computed.

Our results demonstrated a good concordance between tractography of the temporal lobe white matter bundles and dissection and histological data. The interindividual reproducibility of each tract seemed to be good, particularly in the middle part. The variability was more important at both ends, probably in relation to the dispersion of fiber bundles.

Diffusion tensor imaging-based tractography of temporal lobe white matter tracts seemed to be in accordance with histological and dissection data. Taking into account some limitations, it could be of particular interest for the presurgical planning of temporal lobectomy.