Spijkerman JM, et al. - A cross-sectional study was conducted to investigate the confounding influence of the respiratory cycle on net cerebrospinal fluid (CSF) flow and stroke volume measurements. Participants were 12 young, healthy subjects (seven male, age range 19–39 years, average age 28.3 years). The present data indicated that measured net CSF flow was confounded by respiration effects. Results of this study suggested that net CSF flow measurements with phase contrast MRI (PC-MRI) cannot in isolation be directly linked to CSF production.