Andreas Kaneider MD, Presenter: Nothing to Disclose

Gregor Kasprian MD, Abstract Co-Author: Nothing to Disclose

Christian Mitter, Abstract Co-Author: Nothing to Disclose

Thomas Czech, Abstract Co-Author: Nothing to Disclose

Michael Weber PhD, Abstract Co-Author: Nothing to Disclose

Daniela Prayer, Abstract Co-Author: Nothing to Disclose

Diffusion tensor imaging (DTI) based tractography requires an operator dependent and time consuming postprocessing procedure, which is difficult to accomplish during daily clinical workflow. The goal of this study was to investigate the detectability of specific temporal lobe (TL) white matter (WM) tract involvement by comparing 3D tractography results to the qualitative radiological assessment of FA color coded maps alone in patients who underwent different types of unilateral temporal lobe resections.

Postoperative 3 Tesla MR imaging was performed in 32 therapy resistant TL epilepsy patients after temporal lobectomy (21/32), amygdalohippocampectomy (10/32) and lesionectomy (1/32). An axial single shot echo planar DT sequence (b values 0 s/mm2 and 700 s/mm2, 32 gradient encoding directions, TR/TE 6770/60 ms, FOV 224 mm, voxel size 2/2/2 mm) was aquired. The postoperative involvement of main TL trajectories (uncinate, inferior longitudinal and inferior fronto-occipital fasciculus) was rated on FA color coded maps by 2 readers in the axial plane alone followed by the assessment of an additional coronal plane. This data was compared to the results of a 3D deterministic tractography analysis, performed by a third reader.  

Compared with tractography, assessment of axial color coded FA maps alone revealed for both raters a sensitivity ranging from 66.7% to 94.1% respectively 60% to 100% and a specificity of 100%. Estimation of WM changes in the axial and coronal plane showed for both raters a sensitivity ranging from 58.3% to 100% respectively 75% to 100% and a specificity ranging from 94.7% to 100%. The lowest accuracy was found for WM changes affecting the uncinate fasciculus in the region of the temporal stem as well as the inferior fasciculus in the region of the temporal pole.

The rater dependent visual assessment of axial FA color coded maps alone allows a fast and effective detection of specific WM abnormalities after TL epilepsy surgery. The readers accuracy can be substantially increased by including coronal FA map reconstructions. Due to the complex spatial course of some important TL fiber pathways, tractography will still be necessary for a detailed evaluation of postoperative WM changes.

The radiological assessment of multiplanar FA color coded DTI maps is time-efficient and sensitive in the detailed evaluation of postoperative WM changes.

Kaneider, A, Kasprian, G, Mitter, C, Czech, T, Weber, M, Prayer, D, Clinical Radiological Value of FA Maps vs Tractography in the Assessment of White Matter Pathway Involvement after Temporal Lobe Epilepsy Surgery.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9014857.html