Naoki Ohno PhD, Presenter: Nothing to Disclose

Tosiaki Miyati PhD, Abstract Co-Author: Nothing to Disclose

Satoshi Kobayashi MD, Abstract Co-Author: Nothing to Disclose

Toshifumi Gabata MD, Abstract Co-Author: Nothing to Disclose

Osamu Matsui MD, Abstract Co-Author: Research Consultant, Kowa Company, Ltd Research Consultant, Otsuka Holdings Co, Ltd Research Consultant, Eisai Co, Ltd Speakers Bureau, Bayer AG Speakers Bureau, Eisai Co, Ltd

Intravoxel incoherent motion analysis with diffusion weighted-images can provide both diffusion and perfusion information, but these overlap with each other, and theoretically there are three diffusion components, ie., perfusion-related diffusion, fast-free diffusion, and slow-restricted diffusion. To obtain more detailed and precise information noninvasively on perfusion and diffusion in the brain, we analyzed these three diffusion components using triexponential function.

On a 3.0-T MRI, single-shot diffusion echo planar imaging of the brain with multiple b-values of 0 to 3000 s/mm2 (16 points) was performed in healthy volunteers (n=12). The signal intensity at each b value in the caudate nucleus and frontal white matter was obtained. We then derived perfusion-related diffusion, fast-free diffusion, and slow-restricted diffusion coefficients (D  p  , D f , Ds) an d fractions (Fp, Ff, Fs) calculated from triexponential function with a two-step approach. Moreover, biexponential analysis was performed to compare with triexponential analysis. We also determined the regional cerebral blood flow (rCBF) using pseudo-continuou s arterial spin labeling, and assessed the relationship between each diffusion parameter and rCBF.

A positive correlation was found in the caudate nucleus between Dp with triexponential analysis and rCBF, whereas none of the diffusion parameters with biexponential analysis was significantly correlated with rCBF. These results indicate that triexponential analysis could well extract perfusion-related information more than biexponential analysis. Moreover, the mean Fp (3.6%) of the caudate nucleus was generally consistent with the literature values (3.0 to 5.5%) of blood volume fraction in gray matter. On the other hand, there was no significant correlation in the frontal white matter between Dp and rCBF, suggesting that signal intensity of diffusion-weighted image in white matter was less affected by blood perfusion because of the extremely small volume fraction of blood.

Diffusion analysis with triexponential function makes it possible to noninvasively obtain more detailed and precise information on perfusion and diffusion in brain.

Triexponential diffusion analysis may render it possible to noninvasively obtain more detailed and precise information on perfusion and diffusion in brain.

Ohno, N, Miyati, T, Kobayashi, S, Gabata, T, Matsui, O, Novel Triexponential Analysis of Intravoxel Incoherent Motion for Brain Perfusion and Diffusion.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14003679.html