DSI1 is often considered the state-of-the-art technique to analyze q-space measurements sampled from a Cartesian grid. The 3D fastFourier transform is used to directly obtain a discrete version of the EAP (Ensemble Average Propagator). DSI was one of the first techniques used toinfer complex fiber configurations as it allows resolving crossings. In principle, DSI also captures some radial information which, in theory, can be used toextract diffusion features of the EAP. However, a discrete propagator representation suffers from a limited frequency band, which makes infiniteintegration impossible. Hence, EAP derived indices2,3 are problematic and quantitatively questionable, as one needs to artificially normalize andapproximate the infinite integrals. Combined with the recent popularity of DSI in the Human Connectome Project4, it is important to investigate thedifferent angular and EAP indices that can be computed from these DSI datasets. In this work, we investigate alternatives to the discrete model-freeapproach of DSI and investigate the Simple Harmonic Oscillator based Reconstruction and Estimation3 (SHORE) models based on the evaluation of (i)the orientation distribution function (ODF) ; (ii) the return to the origin probability2,3 (RTOP) and (iii) the mean square displacement3 (MSD).
Comparison between discrete and continuous propagator indices from Cartesian q-space DSI sampling
Zucchelli, Mauro;MENEGAZ, Gloria
2014-01-01
Abstract
DSI1 is often considered the state-of-the-art technique to analyze q-space measurements sampled from a Cartesian grid. The 3D fastFourier transform is used to directly obtain a discrete version of the EAP (Ensemble Average Propagator). DSI was one of the first techniques used toinfer complex fiber configurations as it allows resolving crossings. In principle, DSI also captures some radial information which, in theory, can be used toextract diffusion features of the EAP. However, a discrete propagator representation suffers from a limited frequency band, which makes infiniteintegration impossible. Hence, EAP derived indices2,3 are problematic and quantitatively questionable, as one needs to artificially normalize andapproximate the infinite integrals. Combined with the recent popularity of DSI in the Human Connectome Project4, it is important to investigate thedifferent angular and EAP indices that can be computed from these DSI datasets. In this work, we investigate alternatives to the discrete model-freeapproach of DSI and investigate the Simple Harmonic Oscillator based Reconstruction and Estimation3 (SHORE) models based on the evaluation of (i)the orientation distribution function (ODF) ; (ii) the return to the origin probability2,3 (RTOP) and (iii) the mean square displacement3 (MSD).
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