[Poststenotic flow in MRT: phantom measurements using spin-echo and gradient-echo sequences].

Abstract

A flow model was used to study the appearance of poststenotic flow on spin-echo (SE) and fast-field-echo (FFE) images. On SE-images, extensive signal void distal to the stenosis was observed even with low flow velocities. FFE-sequences with short echo time and flow-compensated gradients demonstrated poststenotic loss of signal intensity only with high flow velocities. On FFE-images, the poststenotic signal loss increased with the severity of the stenosis, if total flow across the stenosis was maintained. The lower limit of the mean flow velocity within the stenosis, for which signal void was observed, appeared essentially independent of the degree of the stenosis. The results demonstrate the capability of flow-compensated FFE-sequences to assess poststenotic turbulent flow.