Abstract
Purpose
To evaluate the effect of including the first‐pass of a blood pool agent (BPA) on the image quality of three‐dimensional navigator coronary MRA.
Materials and Methods
A pig model was used to perform: 1) T1 simulation of the BPA, based on actual blood samples, and 2) BPA‐enhanced three‐dimensional navigator coronary MRA, with or without inclusion of the first‐pass of the BPA. The acquisitions with inclusion of the first‐pass were timed with the use of a test bolus. The acquisitions without first‐pass were started one minute after bolus injection (steady‐state). A gradient echo acquisition technique with centric k‐space sampling was applied. Comparison of both acquisitions was based on determination of contrast‐to‐noise ratio (CNR), signal‐to‐noise ratio (SNR), and vessel length.
Results
T1 simulation shows a distinct T1 reduction during first‐pass (to a level below 50 msec), increasing to 190 msec during steady‐state. Images obtained with first‐pass inclusion showed improved CNR (8.6 ± 1.7 vs. 4.5 ± 1.8), SNR (11.9 ± 1.6 vs. 7.4 ± 2.0), and vessel length (99.2 ± 10.9 mm vs. 60.5 ± 21.8 mm) as compared to the acquisitions during steady‐state only (all: P< 0.05).
Conclusion
The image quality of three‐dimensional navigator coronary MRA combined with a gadolinium BPA in pigs is improved when starting the image acquisition during first‐pass of the bolus. J. Magn. Reson. Imaging 2003;18:502–506. © 2003 Wiley‐Liss, Inc.