Three-dimensional navigator coronary MRA with the aid of a blood pool agent in pigs: improved image quality with inclusion of the contrast agent first-pass.
OBJECTIVE
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.


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).


CONCLUSIONS
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.
D000818:Animals; D003287:Contrast Media; D003331:Coronary Vessels / Q000033:anatomy & histology*; D005260:Female; D005682:Gadolinium; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D013552:Swine
D003287:Contrast Media; D005682:Gadolinium