2021 年 39 巻 1 号 p. 34-44
In the diagnosis of white matter lesions by MRI, lesions are recognized depending on whether the signal intensity is higher or lower than that of normal white matter. The images used for diagnosis are displayed in gray scale using window processing. The gray level of each tissue is affected by the window processing. Therefore, it is difficult to quantitatively recognize and evaluate white matter lesions on gray scale image. In order to deal with this problem, an image display method and a quantitative evaluation method based on some reference value which is not affected by window processing are required. Therefore, we introduced a mean signal value of the normal white matter as a reference value by which the white matter signal value is normalized. Next, the normalized signal value of the image was obtained by normalizing the signal value with the reference value. Using the normalized signal value, an image display method for quantitative display and quantitative evaluation of the signal value distribution of the white matter high signal region of FLAIR images were investigated. As a result, it was possible to quantitatively display and evaluate the high signal region of the white matter.
