Comparison of diffusion anisotropy measurements in combination with the flair-technique

Fluid-attenuated inversion recovery (FLAIR) technique offers an effective t ool to diminish partial-volume averaging effects from cerebrospinal (CSF) s ignal with in vivo magnetic resonance imaging. CSF-suppressed and unsuppres sed direction-dependent diffusion-weighted (DW) images are obtained with a DW spin-echo EPI sequence in a single acquisition scheme. Comparison of uns uppressed and CSF-suppressed apparent diffusion coefficient (ADC) maps yiel ds consistent values for brain tissue in volunteers when no partial-volume effects are expected, but differs considerably at borders of parenchyma to ventricles and sulci. From theory and phantom studies, a corrected anisotro py index is introduced considering differences of statistical fit errors. A nisotropy of white matter is observed in normal brain of volunteers. Anisot ropy index maps reveal destruction of fiber tracts in pathologic areas, Res ults of a preliminary study on 12 patients with intra-axial tumors indicate an improved delineation of tumor boundaries of FLAIR ADC maps against unsu ppressed acquisition. (C) 1999 Elsevier Science Inc.