Real-time color flow MRI

A rear-time interactive color flow MRI system capable of rapidly visualizin g cardiac and vascular flow is described. Interleaved spiral phase contrast datasets are acquired continuously, while real-time gridding and phase dif ferencing is used to compute density and velocity maps. These maps are then displayed using a color overlay similar to what is used by ultrasound. For cardiac applications, 6 independent images/sec are acquired with in-plane resolution of 2.4 mm over a 20 cm field of view (FOV). Sliding window recon struction achieves display rates up to 18 images/sec. Appropriate tradeoffs are made for other applications. Flow phantom studies indicate this techni que accurately measures velocities up to 2 m/sec, and accurately captures r eal-time velocity waveforms (comparable to continuous wave ultrasound). In vivo studies indicate this technique is useful for imaging cardiac and vasc ular flow, particularly valvular regurgitation. Arbitrary scan planes can b e quickly localized, and flow measured in any direction. (C) 2000 Wiley-Lis s, Inc.