IMAGE FEATURE-BASED AUTOMATIC CORRECTION OF LOW-FREQUENCY SPATIAL INTENSITY VARIATIONS IN MR-IMAGES

An automatic method of compensating for low-frequency variations in ma gnetic resonance images is presented. Small variations within a tissue type are modelled and a correction function is generated. The method is based completely on image features and does not need a phantom or u ser interaction to generate the compensation function. This image corr ection simplifies digital image analysis and may enhance clinical eval uation. As a result, the correction technique reduces inhomogeneity an d improves contrast. Our results show that the radiofrequency response variation of coils can be reduced. The segmentation process, even wit h a simple threshold method, produces more reliable results when corre cted images are used. The presented method is most useful for images a cquired in the sagital and coronal planes with circular local coils, o r using surface coils, e.g., spine coils. (C) 1997 Elsevier Science In c.