MRI velocimetry in microchannel networks

Magnetic Resonance Imaging (MRI) velocimetry was used for the first time to quantify the interstitial 2-D velocity field of water through an engineered microchannel network constructed from poly-dimethylsiloxane (PDMS). We describe the fabrication of the multilayered PDMS network, which consists of two identical non-communicating capillary networks, each featuring 2 mm deep and 0.9 mm wide staggered channels forming a 10×8 periodic array. The logistics of perfusing the network through multiple interconnects and the velocity extraction are delineated. The effect of a priori or a posteriori methods to estimate the interstitial volume on the accuracy of the pore velocity is shown to be significant.