Dawei Gui1, Nikolaos V Tsekos. 1. Cardiovascular Imaging Laboratory, Mallinckrodt Institute of Radiology, Washington University Medical School, St. Louis, Missouri 63110, USA.
Abstract
PURPOSE: To implement a short-duration magnetization preparation sequence, which consists of a saturation followed by multiple inversion pulses, for imaging of short-T1 species and suppression of long-T1 species. MATERIALS AND METHODS: Computer optimizations were performed to derive preparation schemes that 1) suppress long-T1 background species with T1>or=250 msec, 2) maximize the MZ of contrast-enhanced (CE) structures with T1<or=50 msec, and 3) have a preparation duration in the range of 200 msec. The optimized sequences were tested on a phantom and a pig model instrumented with an intracoronary catheter for infusion of contrast media. RESULTS: Computer simulations generated preparation schemes with durations of 165-225 msec depending on the number of preparation pulses used, which generated saturation of over 98% for T1>250 msec, and about a 30% reduction for 20 msec<T1<50 msec. The phantom studies validated the performance of the optimized sequences. Coronary artery angiograms (380 msec for preparation and image acquisition) demonstrated signal-to-noise ratios (SNRs) in the range of 13-15.5 and contrast-to-noise ratios (CNRs) in the range of 6.3-7.1 in the CE coronary vessels. CONCLUSION: This work demonstrates that fast magnetization-driven preparation schemes can be implemented for fast imaging of CE coronary vessels with efficient saturation of background species. Copyright (c) 2006 Wiley-Liss, Inc.
PURPOSE: To implement a short-duration magnetization preparation sequence, which consists of a saturation followed by multiple inversion pulses, for imaging of short-T1 species and suppression of long-T1 species. MATERIALS AND METHODS: Computer optimizations were performed to derive preparation schemes that 1) suppress long-T1 background species with T1>or=250 msec, 2) maximize the MZ of contrast-enhanced (CE) structures with T1<or=50 msec, and 3) have a preparation duration in the range of 200 msec. The optimized sequences were tested on a phantom and a pig model instrumented with an intracoronary catheter for infusion of contrast media. RESULTS: Computer simulations generated preparation schemes with durations of 165-225 msec depending on the number of preparation pulses used, which generated saturation of over 98% for T1>250 msec, and about a 30% reduction for 20 msec<T1<50 msec. The phantom studies validated the performance of the optimized sequences. Coronary artery angiograms (380 msec for preparation and image acquisition) demonstrated signal-to-noise ratios (SNRs) in the range of 13-15.5 and contrast-to-noise ratios (CNRs) in the range of 6.3-7.1 in the CE coronary vessels. CONCLUSION: This work demonstrates that fast magnetization-driven preparation schemes can be implemented for fast imaging of CE coronary vessels with efficient saturation of background species. Copyright (c) 2006 Wiley-Liss, Inc.