Alexander L. Sukstanskii1
1Radiology, Washington University, St. Louis, MO, United States
Apparent diffusion coefficient (ADC) is analyzed for the case of oscillating diffusion sensitizing gradients. The exact analytical expressions are obtained for the high-frequency expansion of ADC for an arbitrary number of oscillations. The validity conditions of the high-frequency expansion of ADC are analyzed. It is shown that these conditions are substantially different for cos- and sin-type gradients. For the cos-type gradients, the high-frequency regime is reached when T<<tD (T is the period of oscillations, tD is the characteristic diffusion time), whereas for the sin-type gradients, this regime is achieved when the total diffusion time t is smaller tD.