A MRI bolus tagging method for observing helical flow in the descending aorta.

We present a MRI bolus tagging method for exploring the helical nature of blood flow in the aorta. Two image series are collected, the first to quantify longitudinal flow (coronal/sagittal imaging plane-transverse saturation plane), the second to measure rotational flow (transverse imaging plane-coronal/sagittal saturation plane). The experimental protocol has been established in healthy adult volunteers and children with normal vasculature. Our results permit immediate visualization of the unique nature of helical flow in each volunteer. We demonstrate evidence of rapid helical twist, no helical twist, and reversal of twist.