Abstract

Yuka Kayaoka B. S., Akio Ogura PhD*, Tomokazu Takeuchi MS and Daisuke Koyama MS

ABSTRACT

Purpose: The diffusion kurtosis image (DKI) is used for the benign of tumor and malignant differentiation of benign and malignant in tumor, and diagnosis precision improvement of the neurodegenerative disease in a clinic. However, it is pointed out that a mean kurtosis (MK) value depends on the combination of b values to use for calculation. In this study, we examined the dependence of the b values to use for DKI calculation. Methods: The normal brains of six people were imaged in DWI of 16 multi-b value from 0 to 4,500s/mm2. The MK value was calculated by the MR signal of each b value. We changed the number of b values and the maximal b value to use for calculation and compared each MK value and the variation index. Results: The MK value converged to a constant value as the number of the b value to use for analysis was six or more, and the variation index became small. According to the increase of the maximal b value, the MK value decreased and the variation index became small. Conclusion: The number of the b values to use for calculation of DKI was recommended six or more. Moreover, the MK value depends on the maximal b value, but 2,400s/mm2 or more are necessary for the maximal b value in consideration of a variation index.