Optimized distortion correction of epi-based statistical parametrical maps for stereotactic neurosurgery.
A new approach is presented for unwarping geometrical distortions in echo planar imaging (EPI)-based statistical parametrical maps (SPM). With the developed method, a substantial reduction of geometrical distortions in the order of 5-15 mm down to a residue of approximately 1-2 mm was possible, thus allowing reliable activation localization and, hence, interpretation after fusion with undistorted conventional anatomic images. The unwarping procedure is an optimized combination of two distortion correction methods, the "inhomogeneity mapping" and the coregistration approach. Local and global distortions, the first one object-dependent, the second one caused by imperfect gradient waveforms, are reduced. With several examples of patients and volunteers, the applicability for stereotactic neurosurgery is demonstrated.
Department for Stereotactic and Functional Neurosurgery, University of Cologne, Cologne, Germany. Stefan.hunsche@uk-koeln.de
Stefan
S
Hunsche
Dieter
D
Sauner
Harald
H
Treuer
Moritz
M
Hoevels
Volker
V
Hesselmann
Oliver
O
Schulte
Klaus
K
Lackner
Sturm
S
Volker
D000328:Adult; D001921:Brain / Q000033:anatomy & histology / Q000601:surgery*; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000473:pathology / Q000503:physiopathology; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D013238:Stereotaxic Techniques