RT Journal Article T1 Method for bias field correction of brain T1-weighted magnetic resonance images minimizing segmentation error A1 Gispert, Juan D. A1 Reig, Santiago A1 Pascau González-Garzón, Javier A1 Vaquero López, Juan José A1 García Barreno, Pedro A1 Desco Menéndez, Manuel AB This work presents a new algorithm (nonuniform intensity correction; NIC) for correction of intensity inhomogeneities in T1-weighted magnetic resonance (MR) images. The bias field and a bias-free image are obtained through an iterative process that uses brain tissue segmentation. The algorithm was validated by means of realistic phantom images and a set of 24 real images. The first evaluation phase was based on a public domain phantom dataset, used previously to assess bias field correction algorithms. NIC performed similar to previously described methods in removing the bias field from phantom images, without introduction of degradation in the absence of intensity inhomogeneity. The real image dataset was used to compare the performance of this new algorithm to that of other widely used methods (N3, SPM'99, and SPM2). This dataset included both low and high bias field images from two different MR scanners of low (0.5 T) and medium (1.5 T) static fields. Using standard quality criteria for determining the goodness of the different methods, NIC achieved the best results, correcting the images of the real MR dataset, enabling its systematic use in images from both low and medium static field MR scanners. A limitation of our method is that it might fail if the bias field is so high that the initial histogram does not show bimodal distribution for white and gray matter PB Wiley SN 1097-0193 YR 2004 FD 2004-03 LK https://hdl.handle.net/10016/9373 UL https://hdl.handle.net/10016/9373 LA eng DS e-Archivo RD 29 jun. 2024