Surface-to-volume ratio mapping of tumor microstructure using oscillating gradient diffusion weighted imaging

Autor: Kerryanne V. Winters, Olivier Reynaud, Youssef Zaim Wadghiri, Dung Minh Hoang, Sungheon Kim, Dmitry S. Novikov
Rok vydání: 2015
Předmět:
Zdroj: Magnetic Resonance in Medicine. 76:237-247
ISSN: 0740-3194
DOI: 10.1002/mrm.25865
Popis: Purpose To disentangle the free diffusivity (D0) and cellular membrane restrictions, by means of their surface-to-volume ratio (S/V), using the frequency-dependence of the diffusion coefficient D(ω), measured in brain tumors in the short diffusion-time regime using oscillating gradients (OGSE). Methods In vivo and ex vivo OGSE experiments were performed on mice bearing the GL261 murine glioma model (n = 10) to identify the relevant time/frequency (t/ω) domain where D(ω) linearly decreases with ω−1/2. Parametric maps (S/V, D0) are compared with conventional DWI metrics. The impact of frequency range and temperature (20°C versus 37°C) on S/V and D0 is investigated ex vivo. Results The validity of the short diffusion-time regime is demonstrated in vivo and ex vivo. Ex vivo measurements confirm that the purely geometric restrictions embodied in S/V are independent from temperature and frequency range, while the temperature dependence of the free diffusivity D0 is similar to that of pure water. Conclusion Our results suggest that D(ω) in the short diffusion-time regime can be used to uncouple the purely geometric restriction effect, such as S/V, from the intrinsic medium diffusivity properties, and provides a nonempirical and objective way to interpret frequency/time-dependent diffusion changes in tumors in terms of objective biophysical tissue parameters. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc.
Databáze: OpenAIRE
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