Dynamic imaging of contrast-enhanced coronary vessels with a magnetization prepared rotated stripe keyhole acquisition.

Purpose: To evaluate dynamic coronary imaging based on a magnetization prepared contrast-enhanced (CE) rotated stripe keyhole acquisition scheme. Materials and Methods: Background suppression of long T, tissue was used so that the k-space would be selectively dominated by the contribution of the CE vessel. The phase-encoding axis was then adjusted parallel to the long axis of the vessel to sample the significant power spectrum of the vessel. The performance of this approach was evaluated by means of computer simulations and experimental studies on phantoms and a pig model instrumented with an intra-coronary catheter for infusion of contrast media. Results: Computer simulations and phantom studies demonstrated that by rotating the gradient axes to match the k-space pattern of the frequency spectrum, one can reduce the keyhole band to 20% of the full k-space while preserving the structure's lumen width and sharpness. In vivo studies validated those findings, and dynamic angiograms of the CE coronary arteries were obtained as rapidly as 140 msec per image, with an in-plane spatial resolution of 1.5 mm. Conclusion: With efficient background suppression, a rotated stripes keyhole acquisition can efficiently acquire the significant k-space of a CE vessel, and provide improved vessel defirrition with a reduced acquisition matrices scheme.