Error bounds in diffusion tensor estimation using multiple-coil acquisition systems.
We extend the diffusion tensor (DT) signal model for multiple-coil acquisition systems. Considering the sum-of-squares reconstruction method, we compute the Cramér-Rao bound (CRB) assuming the widely accepted noncentral chi distribution. Within this framework, we assess the effect of noise in DT estimation and other measures derived from it, as a function of the number of acquisition coils, as well as other system parameters. We show the applications of CRB in many actual problems related to DT estimation: we compare different gradient field setup schemes proposed in the literature and show how the CRB can be used to choose a convenient one; we show that for fiber-type anisotropy tensors the ellipsoidal area ratio (EAR) can be estimated with less error than other scalar factors such as the fractional anisotropy (FA) or the relative anisotropy (RA), and that for this type of anisotropy tensors, increasing the number of coils is equivalent to increasing the signal-to-noise ratio, i.e., the information of the different coils can be regarded as independent. Also, we present results showing the CRB of several parameters for actual DT-MRI data. We conclude that the CRB is a valuable tool to optimal experiment design in DT-related studies.
['Beltrachini|Leandro|L|', 'von Ellenrieder|Nicolás|N|', 'Muravchik|Carlos Horacio|CH|']
D000465:Algorithms D056324:Diffusion Tensor Imaging D004867:Equipment Design D019544:Equipment Failure Analysis D007089:Image Enhancement D007090:Image Interpretation, Computer-Assisted D010363:Pattern Recognition, Automated D015203:Reproducibility of Results D012680:Sensitivity and Specificity D059629:Signal-To-Noise Ratio
Noncentral chi distribution Cramér–Rao bound Measurement noise