Measuring cellular-interstitial water exchange time in patients with head and neck cancer using time-dependent diffusion experiments

Cellular-interstitial water exchange time has been suggested to be associated with a number of important cellular properties such as membrane permeability, tumor aggressiveness and treatment response. In this study we investigated the reliability of measuring water exchange times based on diffusivity and diffusional kurtosis at long diffusion times. We used two well-established diffusion phantoms and found that diffusion and kurtosis show stable values over a wide range of diffusion times. In head and neck cancer patients, we found that the Kärger model is a valid model for measuring water exchange time in metastatic lymph node voxels.