Histogram analyses of apparent diffusion coefficients with different diffusion gradients in diffusion-weighted imaging of normal pancreas / 中华胰腺病杂志

ABSTRACT

Objective To investigate the characteristics of histogram analysis and differences of apparent diffusion coefficient ( ADC) for normal pancreas with different diffusion gradients of diffusion weighted imaging (DWI) at 3. 0T. Methods Three unidirectional diffusion gradients (X, Y or Z direction) and three orthogonal diffusion gradient DWI data of 21 volunteers with normal pancreas were retrospectively analyzed. The histogram parameters of mean ADC, percentile, skewness, peak and the like were measured based on home-made DWI post-processing software, and the differences on histogram parameters obtained from 4 different diffusion gradients were compared by using Kruskal Wallis test. Results There was no significant difference on the mean ADC, skewness, percentile and the like for normal pancreas among 3 unidirectional diffusion gradients and tri-orthogonal diffusion gradient DWIs, but there was significant difference on the mean kurtosis value ( X3. 16 ± 1. 44, Y4. 72 ± 2. 26, Z4. 47 ± 2. 1, tri-orthogonal3. 69 ± 1. 82; χ2 = -9. 84, P=0. 02). Further analyses results showed that the ADC kurtosis of normal pancreas obtained from X-directional diffusion gradient DWI was significantly smaller than that of the direction of Y or Z, and the difference was statistically significant (P<0.05). Conclusions The ADC kurtosis of normal pancreas is related to the direction of diffusion gradient in DWI, and the ADC kurtosis of normal pancreas obtained by X-direction diffusion gradient is the smallest.