01715nas a2200157   4500008004100000020001400041245005000055210004700105260001200152300001600164490000700180520123000187100002801417700002201445856009001467       1999                        eng d  a0740-319400aOn standardizing the MR image intensity scale0 astandardizing the MR image intensity scale  c1999///  a1072 - 10810 v423 aThe lack of a standard image intensity scale in MRI causes manydifficulties in image display and analysis. A two-step 
postprocessing method is proposed for standardizing the 
intensity scale in such a way that for the same MR protocol and 
body region, similar intensities will have similar tissue 
meaning. In the first step, the parameters of the standardizing 
transformation are "learned" from a set of images. In the second 
step, for each MR study these parameters are used to map their 
histogram into the standardized histogram. The method was tested 
quantitatively on 90 whole-brain studies of multiple sclerosis 
patients for several protocols and qualitatively for several 
other protocols and body regions. Measurements using mean 
squared difference showed that the standardized image 
intensities have statistically significantly (P < 0.01) more 
consistent range and meaning than the originals. Fixed gray 
level windows can be established for the standardized images and 
used for display without the need of per case adjustment. 
Preliminary results also indicate that the method facilitates 
improving the degree of automation of image segmentation. Magn 
Reson Med 42:1072-1081, 1999.
1 aNyúl, László, Gábor1 aUdupa, Jayaram, K  uhttps://www.inf.u-szeged.hu/publication/on-standardizing-the-mr-image-intensity-scale